Investments [Abstract] Investments in Marketable Equity Securities Marketable Securities [Table Text Block] Loss on marketable equity securities Gain (Loss) on Securities [Table Text Block] Property, Plant and Equipment [Abstract] Land Land Buildings Buildings and Improvements, Gross Machinery, equipment and fixtures Machinery and Equipment, Gross Leasehold improvements Leasehold Improvements, Gross Construction in progress Construction in Progress, Gross Property, plant and equipment, gross Property, Plant and Equipment, Gross Less accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property, plant and equipment, net Property, Plant and Equipment, Net Income Tax Disclosure [Abstract] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table] SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain] SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain] Deferred Tax Valuation Allowance [Member] SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member] Valuation Allowance [Line Items] Valuation Allowance [Line Items] SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] Balance at Beginning of Period SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount Tax Expense and Revaluation Valuation Allowances And Reserves, Charged To Cost And Expense And Other Charges Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs, charged to costs and expenses and other charges. Deductions SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction Balance at End of Period Acquisitions And Dispositions [Abstract] Acquisitions and Dispositions Acquisitions and Dispositions of Businesses Mergers, Acquisitions and Dispositions Disclosures [Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Schedule of Goodwill [Table] Schedule of Goodwill [Table] Subsegments [Axis] Subsegments [Axis] Subsegments [Domain] Subsegments [Domain] Higher Education [Member] Higher Education [Member] Higher Education [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Forney [Member] Forney [Member] Forney [Member] Segments [Axis] Segments [Axis] Segment [Domain] Segments [Domain] Education [Member] Education [Member] Education [Member] Other Businesses [Member] Other Segments [Member] Goodwill [Line Items] Goodwill [Line Items] Asset Impairment Charges Asset Impairment Charges Number of businesses recorded impairment of goodwill Number Of Businesses Recorded Impairment Of Goodwill The number of businesses that recorded impairment of goodwill. Goodwill, Impairment Loss Goodwill, Impairment Loss Goodwill and Intangible Asset Impairment Goodwill and Intangible Asset Impairment Statement of Financial Position [Abstract] Statement [Table] Statement [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Class A Common Stock [Member] Common Class A [Member] Class B Common Stock [Member] Common Class B [Member] Statement [Line Items] Statement [Line Items] Assets Assets [Abstract] Current Assets Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Restricted cash Restricted Cash and Cash Equivalents Investments in marketable equity securities and other investments Investments In Marketable Equity Securities And Other Investments Total debt and equity financial instruments including: (1) securities held-to-maturity, (2) trading securities, and (3) securities available-for-sale which are intended to be held for less than one year or the normal operating cycle, whichever is longer. Also includes other current investments such as mutual funds. Accounts receivable, net Accounts and Other Receivables, Net, Current Income taxes receivable Income Taxes Receivable, Current Inventories and contracts in progress Inventory, Net of Allowances, Customer Advances and Progress Billings Other current assets Other Assets, Current Total Current Assets Assets, Current Property, Plant and Equipment, Net Investments in Affiliates Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Goodwill, Net Goodwill Indefinite-Lived Intangible Assets Indefinite-lived Intangible Assets (Excluding Goodwill) Amortized Intangible Assets, Net Finite-Lived Intangible Assets, Net Prepaid Pension Cost Assets for Plan Benefits, Defined Benefit Plan Deferred Income Taxes Deferred Tax Assets, Net Deferred Charges and Other Assets Other Assets, Noncurrent Total Assets Assets Liabilities and Equity Liabilities and Equity [Abstract] Current Liabilities Liabilities, Current [Abstract] Accounts payable and accrued liabilities Accounts Payable and Accrued Liabilities, Current Deferred revenue Deferred Revenue, Current Income taxes payable Accrued Income Taxes, Current Current portion of long-term debt Debt, Current Total Current Liabilities Liabilities, Current Accrued Compensation and Related Benefits Deferred Compensation Liability, Classified, Noncurrent Other Liabilities Other Liabilities, Noncurrent Deferred Income Taxes Deferred Tax Liabilities, Net Mandatorily Redeemable Noncontrolling Interest Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Share Value, Amount, Noncurrent Long-Term Debt Long-term Debt, Excluding Current Maturities Total Liabilities Liabilities Commitments and Contingencies (Notes 17 and 18) Commitments and Contingencies Redeemable Noncontrolling Interests Redeemable Noncontrolling Interest, Equity, Carrying Amount Preferred Stock, $1 par value; 977,000 shares authorized, none issued Preferred Stock, Value, Issued Common Stockholders’ Equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Common stock Common Stock, Value, Issued Capital in excess of par value Additional Paid in Capital Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive income, net of taxes Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Cumulative foreign currency translation adjustment Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax Unrealized gain on available-for-sale securities Accumulated Other Comprehensive Income (Loss), Debt Securities, Available-for-sale, Adjustment, after Tax Unrealized gain on pensions and other postretirement plans Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax Cash flow hedge Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax Cost of 14,699,041 and 14,495,506 shares of Class B common stock held in treasury Treasury Stock, Value Total Equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total Liabilities and Equity Liabilities and Equity Other Nonoperating Income (Expense) [Abstract] Other Non-Operating Income (Expense) Other Income and Other Expense Disclosure [Text Block] Statement of Cash Flows [Abstract] Cash Flows from Operating Activities Net Cash Provided by (Used in) Operating Activities [Abstract] Net Income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation, amortization and goodwill and other long-lived asset impairment Depreciation, Depletion, Amortization And Impairment The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets, including write-downs for impairments. Net pension benefit Net Periodic Benefit For Defined Benefit Pension Plans Excluding Early Retirement Program, Special Separation Benefit Expense, Curtailment And Settlement The net periodic benefit or expense for defined benefit pension plans excluding the early retirement program and special separation benefit expense, curtailment, settlement and other programs separately disclosed in the financial statements. Net pension benefit Net Periodic Benefit For Defined Benefit Pension Plans Excluding Early Retirement Program and Special Separation Benefit Expense The net periodic benefit or expense for defined benefit pension plans excluding the early retirement program and special separation benefit expense. Early retirement and special separation benefit program expense Defined Benefit Plan, Cost of Providing Special and Contractual Termination Benefits Loss on marketable equity securities and cost method investments, net Unrealized Gain (Loss) on Investments Stock-based compensation expense, net Share-based Compensation Debt extinguishment costs Gain (Loss) on Extinguishment of Debt, before Write off of Debt Issuance Cost Foreign exchange loss (gain) Foreign Currency Transaction Gain (Loss), before Tax Net (gain) loss on sales and disposition of businesses Net Gain Loss On Sales And Disposition of Businesses Gain (loss) from sale or disposal of an organization or integrated set of activities (for example, but not limited to, a partnership or corporation) engaged in providing a product or service in a commercial, industrial, or professional environment. Net (gain) loss on dispositions, sales or write-downs of marketable equity securities and cost method investments Gain (Loss) on Disposition of Assets Net (gain) loss on dispositions, sales or write-downs of marketable equity securities and cost method investments Marketable Securities And Cost Method Investments Realized Gain Loss This item represents the net total realized gain (loss) included in earnings for the period as a result of selling marketable securities categorized as trading, available-for-sale, or held-to-maturity. Additionally, this item would include any gains (losses) realized during the period from the sale of investments accounted for under the cost method of accounting. This item also includes losses recognized for other than temporary impairments (OTTI) of the marketable securities and cost method investments. Gain on sale of an equity affiliate Equity Method Investment, Realized Gain (Loss) on Disposal Equity in (earnings) losses of affiliates, net of distributions Income (Loss) from Equity Method Investments, Net of Dividends or Distributions Equity in (earnings) losses of affiliates, net of distributions Income Loss From Equity Method Investments Net Of Dividends Or Distributions Including Impairment This element represents the undistributed income (or loss) of equity method investments, net of dividends or other distributions received from unconsolidated subsidiaries, certain corporate joint ventures, and certain noncontrolled corporations; such investments are accounted for under the equity method of accounting. This element excludes distributions that constitute a return of investment, which are classified as investing activities. This element also includes impairment charges recorded. (Benefit from) provision for deferred income taxes Deferred Income Tax Expense (Benefit) Net (gain) loss on sales or write-downs of property, plant and equipment GainLossOnSaleOrWritedownOfPropertyPlantEquipment Amount of gain (loss) on sale, disposal or write-down of property, plant and equipment assets. Change in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable, net Increase (Decrease) in Accounts Receivable Inventories Increase (Decrease) in Inventories Accounts payable and accrued liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Deferred revenue Increase (Decrease) in Deferred Revenue Income taxes receivable/payable Increase (Decrease) in Income Taxes Other assets and other liabilities, net Increase (Decrease) in Other Operating Assets and Liabilities, Net Other Other Operating Activities, Cash Flow Statement Net Cash Provided by Operating Activities Net Cash Provided by (Used in) Operating Activities Cash Flows from Investing Activities Net Cash Provided by (Used in) Investing Activities [Abstract] Investments in certain businesses, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Purchases of property, plant and equipment Payments to Acquire Property, Plant, and Equipment Proceeds from sales of marketable equity securities Proceeds from Sale of Available-for-sale Securities, Equity Purchases of marketable equity securities Payments to Acquire Available-for-sale Securities, Equity Advance related to Kaplan University transaction and loan to affiliate AdvanceRelatedToKaplanUniversityTransactionAndLoanToAffiliate Payments made for advance related to Kaplan University transaction and loan to affiliate. Investments in equity affiliates, cost method and other investments Payments To Acquire Equity Method Cost Method Investments And Other Investments The cash outflow associated with the purchase of equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence, cost method investments or other investments, not including marketable equity securities. Advance related to Kaplan University transaction and loan to affiliate Payments to Fund Long-term Loans to Related Parties Net (payments) proceeds from sales of businesses, property, plant and equipment and other assets Net Proceeds From Sale Of Businesses Property Plant And Equipment And Other Assets The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period. Also included is the cash inflow from the sale of long-lived, physical assets and other assets. Return of investment in equity affiliates Proceeds from Equity Method Investment, Distribution, Return of Capital Investments in equity affiliates and cost method investments Payments To Acquire Equity Method And Cost Method Investments The cash outflow associated with the purchase of equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence or cost method investments. Other Payments for (Proceeds from) Other Investing Activities Net Cash Used in Investing Activities Net Cash Provided by (Used in) Investing Activities Cash Flows from Financing Activities Net Cash Provided by (Used in) Financing Activities [Abstract] Repayments of borrowings and early redemption premium RepaymentsOfLongTermDebtAndDebtExtinguishmentCosts The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer and for cost from early extinguishment of debt, which includes only the premium paid. Issuance of borrowings Proceeds from Issuance of Long-term Debt Common shares repurchased Payments for Repurchase of Common Stock Dividends paid Payments of Ordinary Dividends Purchase of noncontrolling interest and deferred payment of acquisition Deferred Payments Of Acquisition And Noncontrolling Interest Deferred payments made related to acquisitions and noncontrolling interest. Purchase of noncontrolling interest and deferred payment of acquisition Purchase of Noncontrolling Interest and Deferred Payment of Acquisition Cash outflow for purchase of noncontrolling interest and deferred payment of an acquisition. Payments of financing costs Payments of Financing Costs Deferred payments of acquisition and noncontrolling interest Payments for Repurchase of Redeemable Noncontrolling Interest (Repayments of) proceeds from bank overdrafts Proceeds from (Repayments of) Bank Overdrafts Other Proceeds from Stock Options Exercised Other Proceeds from (Payments for) Other Financing Activities Payment Of Distribution To Affiliate Payment Of Distribution To Affiliate Cash distribution from the Company to an affiliate. Net Cash Used in Financing Activities Net Cash Provided by (Used in) Financing Activities Effect of Currency Exchange Rate Change Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Net Decrease in Cash and Cash Equivalents and Restricted Cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Cash and Cash Equivalents and Restricted Cash at Beginning of Year Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash and Cash Equivalents and Restricted Cash at End of Year Supplemental Cash Flow Information Supplemental Cash Flow Information [Abstract] Cash paid during the year for: Cash Paid During The Year For: [Abstract] -- None. No documentation exists for this element. -- Income taxes Income Taxes Paid, Net Interest Interest Paid, Excluding Capitalized Interest, Operating Activities Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Axis] CarryforwardsPeriod [Axis] -- None. No documentation exists for this element. -- Operating Loss Carryforward Period [Domain] Carryforward Period [Domain] Carryforward Period Domain 2019 [Member] Loss Carry Forwards Expirations Year One [Member] Loss Carry Forwards Expirations Year One Member 2020 [Member] Loss Carry Forwards Expirations Year Two [Member] Loss Carry Forwards Expirations Year Two [Member] 2021 [Member] Loss Carry Forwards Expirations Year Three [Member] Loss Carry Forwards Expirations Year Three Member 2022 [Member] Loss Carry Forwards Expirations Year Four [Member] Loss Carry Forwards Expirations Year Four Member 2023 [Member] Loss Carry Forwards Expirations Year Five [Member] Loss Carry Forwards Expirations Year Five Member 2024 and after [Member] Loss Carry Forwards Expirations After Year Five [Member] Loss Carry Forwards Expirations After Year Five Member Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] State [Member] State and Local Jurisdiction [Member] U.S. Federal [Member] Domestic Tax Authority [Member] non-U.S. [Member] Foreign Tax Authority [Member] Operating Loss Carryforwards [Line Items] Operating Loss Carryforwards [Line Items] Income tax loss carryforwards to expire Income Tax Loss Carryforwards Subject to Expiration Income tax loss carryforwards subject to expiration. Income tax loss carryforwards to be fully utilized Tax Loss Carryforward Prior Stock Acquisition Utilized Income tax loss carryforwards obtained as a result of prior stock acqusitions to be fully utilized. Accounts Receivable Accounts Payable And Accrued Liabilities [Abstract] -- None. No documentation exists for this element. -- Cash overdrafts Bank Overdrafts Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization and Nature of Operations Nature of Operations [Text Block] Capital Stock, Stock Awards, and Stock Options [Abstract] -- None. No documentation exists for this element. -- Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Corporate office [Member] Corporate, Non-Segment [Member] Exercise Price Range [Axis] Exercise Price Range [Axis] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Domain] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Domain] Exercise Price Above Fair Market Value Of Common Stock [Member] Exercise Price Above Fair Market Value Of Common Stock [Member] -- None. No documentation exists for this element. -- Transaction [Axis] Transaction [Axis] Transaction [Axis] Transaction Type [Domain] Transaction Type [Domain] Transaction Type [Domain] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Kaplan Restricted Stock [Member] Kaplan Restricted Stock [Member] -- None. No documentation exists for this element. -- Kaplan Stock Option [Member] Kaplan Stock Option [Member] -- None. No documentation exists for this element. -- Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] 2003 Employee Stock Option Plan [Member] 2003 Employee Stock Option Plan [Member] 2003 Employee Stock Option Plan reserves shares of the Company's Class B common stock for options to be granted under the plan. [Member] 2012 Incentive Compensation Plan [Member] 2012 Incentive Compensation Plan [Member] 2012 Incentive Compensation Plan which authorizes the awarding of Class B common stock to key employees in the form of stock awards, stock options and other awards involving the actual transfer of shares. [Member] Segments [Axis] Dividends [Axis] Dividends [Axis] Dividends [Domain] Dividends [Domain] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Maximum [Member] Maximum [Member] Minimum [Member] Minimum [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits, by Title of Individual [Axis] Title of Individual [Axis] Title of Individual with Relationship to Entity [Domain] Relationship to Entity [Domain] Senior Manager [Member] Senior Manager [Member] Senior Manager Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Restricted Stock [Member] Restricted Stock [Member] Kaplan Stock Option and Restricted Stock [Member] Kaplan Stock Option and Restricted Stock [Member] Kaplan Stock Option and Restricted Stock [Member] Stock Compensation Plan [Member] Stock Compensation Plan [Member] Employee Stock Option [Member] Employee Stock Option [Member] 2017 Options Granted [Member] 2017 Options Granted [Member] 2017 Options Granted [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Right to elect Board of Directors percentage Right To Elect Board Of Directors Percentage Right To Elect Board Of Directors Percentage Shares repurchased by company Treasury Stock, Shares, Acquired Cost of shares repurchased by company Number of shares authorized to be repurchased Stock Repurchase Program, Number of Shares Authorized to be Repurchased Number of shares authorized to be repurchased remaining under previous authorization StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchasedUnderPreviousAuthorization Number of shares authorized to be repurchased remaining under previous authorization. Authorized shares remaining for repurchase Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased Shares reserved for stock awards granted under the plan Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Shares reserved for issuance Common Stock, Capital Shares Reserved for Future Issuance Shares subject to award outstanding Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Shares available for future awards Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Number of shares forfeited due to modification Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Incremental stock compensation expense, net of forfeitures, due to modification Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Incremental Compensation Cost Share awards outstanding, restriction will lapse in 2019 Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number Year One Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number Year One Share awards outstanding, restriction will lapse in 2020 Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number Year Two Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number Year Two Share awards outstanding, restriction will lapse in 2021 Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number Year Three Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number Year Three Number of shares awarded in 2019 Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Stock-based compensation expense Allocated Share-based Compensation Expense Total unrecognized compensation expense Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Years over which cost expected to be recognized Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Number of stock options forfeited due to modification Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Options outstanding exercisable now Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number Exercisable Now Options outstanding exercisable now. Options outstanding exercisable in 2019 Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number Exercisable Year One Options outstanding exercisable in year one. Options outstanding exercisable in 2020 Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number Exercisable Year Two Options outstanding exercisable in year two. Options outstanding exercisable in 2021 Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number Exercisable Year Three Options outstanding exercisable in year three. Options outstanding exercisable in 2022 Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number Exercisable Year Four Options outstanding exercisable in year four. Options outstanding exercisable in 2023 Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number Exercisable Year Five Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number Exercisable Year Five Intrinsic value of options outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Intrinsic value of options exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Intrinsic value of options unvested Share Based Compensation Arrangement By Share Based Payment Award Options Unvested Intrinsic Value Share Based Compensation Arrangement By Share Based Payment Award Options Unvested Intrinsic Value Market value of company's stock Common Stock Stated Market Value Per Share Common Stock Stated Market Value Per Share Options unvested, shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares Options unvested, average exercise price Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Nonvested Weighted Average Exercise Price The weighted average price as of the end of the year at which grantees can acquire the shares reserved for issuance under the stock option plan which are not vested. Options unvested, weighted average remaining contractual term, years Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Nonvested Weighted Average Remaining Contractual Term The weighted average period between the balance sheet date and expiration for all awards outstanding but not vested under the plan, which may be expressed in a decimal value for number of years. Exercised, Number of Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Intrinsic value of options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Tax benefit from stock option exercises Employee Service Share-based Compensation, Tax Benefit from Exercise of Stock Options Number of shares granted Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Weighted average fair value, granted options Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Fair value of company common stock Fair Value Of Company Common Stock Fair value of company common stock Stock options outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Accrual balance related to stock based compensation Deferred Compensation Share-based Arrangements, Liability, Current and Noncurrent Stock compensation payouts Deferred Compensation Arrangement with Individual, Distribution Paid Shares excluded from earnings per share Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Dividends declared per common share Common Stock, Dividends, Per Share, Declared Conversion of Class A shares to Class B Conversion of Stock, Shares Converted Retirement Benefits, Description [Abstract] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Pension Plans [Member] Pension Plan [Member] Supplemental Executive Retirement Plan (SERP) [Member] Supplemental Employee Retirement Plan [Member] Other Postretirement Plans [Member] Other Postretirement Benefits Plan [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Noncurrent asset Current liability Liability, Defined Benefit Plan, Current Noncurrent liability Liability, Defined Benefit Plan, Noncurrent Recognized asset (liability) Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position Other Income and Expenses (Narrative) [Abstract] Other Income and Expenses (Narrative) [Abstract] Schedule of Non-Operating Income (Expense) [Table] Schedule of Non-Operating Income (Expense) [Table] Schedule of Non-Operating Income (Expense) [Table] Sale Of KHE Campuses Business [Member] Sale Of KHE Campuses Business [Member] Sale of KHE Campuses business [Member] Kaplan Corporate and Other [Member] Kaplan Corporate and Other [Member] Kaplan Corporate And Other [Member] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Vocational School Company [Member] Vocational School Company [Member] Vocational School Company [Member] Residential Healthcare Group Inc [Member] Residential Healthcare Group Inc [Member] Residential Healthcare Group Inc [Member] Colloquy [Member] Colloquy [Member] Colloquy [Member] Kaplan University Transaction [Member] Kaplan University Transaction [Member] Kaplan University Transaction [Member] Residential And Michigan Hospital Joint Venture [Member] Residential And Michigan Hospital Joint Venture [Member] Residential and a Michigan hospital joint venture [Member] Schedule of Non-Operating (Expense) Income [Line Items] Schedule of Non-Operating Income (Expense) [Line Items] [Line Items] for Schedule of Non-Operating Income (Expense) [Table] Loss on Guarantor Lease Obligations Loss on Guarantor Lease Obligations The amount of loss recognized on guarantor lease obligations. Gains on cost method investments Equity Securities without Readily Determinable Fair Value, Upward Price Adjustment, Annual Amount Net gain (loss) on sales of businesses Gain (Loss) on Disposition of Business Number Of Businesses Disposed Number Of Businesses Disposed The number of businesses disposed of by the entity during the period. Gain Related to Contingent Consideration Gain Related to Contingent Consideration Contingent consideration gain related to the sale of a business. Impairment of cost method investment Cost-method Investments, Other than Temporary Impairment Net gain on sale of property, plant and equipment Gain (Loss) on Disposition of Property Plant Equipment Ownership percentage of investment in affiliate Equity Method Investment, Ownership Percentage Gain on formation of a joint venture Deconsolidation, Gain (Loss), Amount Fair Value Disclosures [Abstract] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy and NAV [Domain] Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Money market investments Money Market Funds, at Carrying Value Marketable equity securities Equity Securities, FV-NI Marketable equity securities Available-for-sale Securities, Equity Securities Other current investments Other Short-term Investments Interest rate swap Interest Rate Cash Flow Hedge Asset at Fair Value Total Financial Assets Investments, Fair Value Disclosure Liabilities Liabilities [Abstract] Deferred compensation plan liabilities Deferred Compensation Liability, Current and Noncurrent Interest rate swap Interest Rate Cash Flow Hedge Liability at Fair Value Mandatorily Redeemable Noncontrolling Interest Mandatorily Redeemable Noncontrolling Interest Fair Value Disclosure Fair value of the Noncontrolling interest that an entity is required to redeem for cash or other assets at a fixed or determinable date or upon the occurrence of an event. Total Financial Liabilities Financial Liabilities Fair Value Disclosure Quarterly Financial Information Disclosure [Abstract] Operating Revenues Revenues Operating Costs and Expenses Operating Costs and Expenses [Abstract] Operating Operating Expense Generally recurring costs associated with normal operations including the portion of these expenses which can be clearly related to production and included in cost of sales or services. Excludes selling, general and administrative expenses. Selling, general and administrative Selling, General and Administrative Expenses The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc. Also includes expenses such as bad debt expense, and gain (loss) on disposition of assets. Depreciation of property, plant and equipment Depreciation Amortization of intangible assets Amortization of Intangible Assets Impairment of goodwill and other long-lived assets Total Operating Costs and Expenses Costs and Expenses Income from Operations Operating Income (Loss) Equity in earnings (losses) of affiliates, net Income (Loss) from Equity Method Investments Interest income Investment Income, Interest Interest expense Interest Expense Debt extinguishment costs Gain (Loss) on Extinguishment of Debt Non-operating pension and postretirement benefit income, net Net Periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component (Loss) gain on marketable equity securities, net Equity Securities, FV-NI, Gain (Loss) Other income (expense), net Other Nonoperating Income (Expense) Income Before Income Taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Provision for Income Taxes Income Tax Expense (Benefit) Net Income Attributable to Noncontrolling Interests Income (Loss) Attributable to Redeemable Noncontrolling Interest and Nonredeemable Noncontrolling Interest Amount of Net Income (Loss) attributable to redeemable noncontrolling interest and nonredeemable noncontrolling interest. Net Income (Loss) Attributable to Parent Net Income (Loss) Attributable to Parent Comprehensive Income (Loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Per Share Information Attributable to Graham Holdings Company Common Stockholders Earnings Per Share [Abstract] Basic net income per common share (in usd per share) Earnings Per Share, Basic Basic average number of common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Diluted net income per common share (in usd per share) Earnings Per Share, Diluted Diluted average number of common shares outstanding (in shares) Weighted Average Number Of Potentially Dilutive Shares Outstanding The weighted average number of shares outstanding that could potentially dilute basic EPS. Property, Plant and Equipment Property, Plant and Equipment Disclosure [Text Block] Loss on marketable equity securities, net Plus: Net losses in earnings from marketable equity securities sold Equity Securities, FV-NI, Realized Gain (Loss) Net unrealized losses in earnings from marketable equity securities still held at the end of the year Equity Securities, FV-NI, Unrealized Gain (Loss) Leases And Other Commitments [Abstract] -- None. No documentation exists for this element. -- Schedule of Operating Leased Assets [Table] Schedule of Operating Leased Assets [Table] Television Broadcasting [Member] Television Broadcasting [Member] Television Broadcasting [Member] Operating Leased Assets [Line Items] Operating Leased Assets [Line Items] Future minimum sublease payments due Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals Rent expense for operating leases Operating Leases, Rent Expense Sublease rental income Operating Leases, Income Statement, Sublease Revenue Long-term programming purchase commitment Long-term Purchase Commitment, Amount Commitments and Contingencies Disclosure [Abstract] Loss Contingencies [Table] Loss Contingencies [Table] Kaplan International [Member] Kaplan International [Member] Kaplan International [Member] UK Pathways [Member] UK Pathways [Member] UK Pathways [Member] Litigation Case [Axis] Litigation Case [Axis] Litigation Case [Domain] Litigation Case [Domain] Diaz Case [Member] Diaz Case [Member] United States of America ex rel. Carlos Urquilla-Diaz et al. v. Kaplan University et al., included three separate complaints: Diaz, Wilcox and Gillespie. Diaz Claims [Member] Diaz Claims [Member] Diaz claims included in the United States of America ex rel. Carlos Urquilla-Diaz et al. v. Kaplan University et al. complaint. [Member] Celtic Healthcare Allegheny Health Network Joint Venture [Member] CelticHealthcareAlleghenyHealthNetworkJointVenture [Member] A joint venture formed between Celtic Healthcare and Allegheny Health Network Income Tax Authority, Name [Axis] Income Tax Authority, Name [Axis] Income Tax Authority, Name [Domain] Income Tax Authority, Name [Domain] Her Majesty's Revenue and Customs (HMRC) [Member] Her Majesty's Revenue and Customs (HMRC) [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Number of existing legal claims or proceedings that are likely to have a material effect on the Company's business Loss Contingency, Pending Claims, Number Loss contingency, estimate of possible loss Loss Contingency, Estimate of Possible Loss The number of separate complaints included in the Diaz case that received rulings Separate Complaints Included In A Series Of Rulings On Number of separate complaints included in the Diaz case that the U.S. District Court for the Southern District of Florida issued a series of rulings on. Remaining employment claim in the Diaz complaint Remaining Employment Claim In The Diaz Complaint Number of remaining employment claim in the Diaz complaint with the U.S. District Court for the Southern District of Florida. Number of claims affirmed for dismissal by US Court of Appeals Number Of Claims Affirmed For Dismissal by US Court of Appeals Number of claims affirmed for dismissal by the U.S. Court of Appeals for the Eleventh Judicial Court. Number of claims appealed Number of Claims Appealed Number of claims appealed to and heard by the U.S. Court of Appeals for the Eleventh Judicial Court. Loss on Guarantor Lease Obligations Number of conditions out of compliance Number Of Conditions Out Of Compliance The number of conditions out of compliance. Number of days of noncompliance Number Of Days Of Noncompliance The number of days of noncompliance. Amount of penalties per day or per instance of noncompliance Amount Of Penalties Per Day Or Per Instance Of Noncompliance The amount of penalties per day or per instance of noncompliance. Number of pending ED program reviews Number of pending program reviews Number of pending program reviews. Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Foreign Currency Translation Adjustments [Member] Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Unrealized Gains (Losses) on Available- for- Sale Securities [Member] Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] Pension and Other Postretirement Plans [Member] Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Net Actuarial Loss [Member] Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member] Net Prior Service Cost [Member] Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member] Curtailment (Gains) Losses Included in Net Income [Member] AccumulatedDefinedBenefitPlansAdjustmentCurtailmentGainsIncludedInNetIncome [Member] Accumulated other comprehensive (income) loss related to the curtailment gains included in net income component of defined benefit plans attributable to the parent. Cash Flow Hedge Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Member] Reclassification out of Accumulated Other Comprehensive Income [Member] Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Other (expense) income, net Interest expense Provision for (Benefit from) Income Taxes Net of Tax Reclassifications, before tax Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax Provision for income taxes Reclassification from AOCI, Current Period, Tax Reclassifications, net of tax Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Schedule of assets acquired and liabilities assumed Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Acqusition Pro Forma Financial Information Business Acquisition, Pro Forma Information [Table Text Block] Information related to a Disposal Group Schedule Of Disposal Groups Excluding Discontinued Operations Income Statement Balance Sheet And Additional Disclosures [Table Text Block] Tabular disclosure of information related to a disposal group. Excludes a discontinued operation, disposal classified as held-for-sale or disposed of by means other than sale or disposal of an individually significant component. Document and Entity Information [Abstract] Document and Entity Information [Abstract] Entities [Table] Entities [Table] Entity Information [Line Items] Entity Information [Line Items] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Shell Company Entity Shell Company Entity Current Reporting Status Entity Current Reporting Status Entity Voluntary Filers Entity Voluntary Filers Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Public Float Entity Public Float Entity Common Stock, Shares Outstanding (in shares) Entity Common Stock, Shares Outstanding Accounts Receivable Accounts Payable And Accrued Liabilities Accounts Receivable Accounts Payable And Accrued Liabilities [Text Block] The entire disclosure of Accounts Receivable Accounts Payable And Accrued Liabilities Revenue from Contract with Customer [Abstract] Contract Costs Capitalized During the Period Contract Costs Capitalized During the Period Capitalized contract costs associated with new contracts entered into during the period. Costs amortized during the period Capitalized Contract Cost, Amortization Change in Capitalized Contract Cost, Other Change in Capitalized Contract Cost, Other Change in capitalized contract cost, other Balance of costs to obtain a contract Capitalized Contract Cost, Net Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Early Retirment Program Expense [Axis] Early Retirment Program Expense [Axis] -- None. No documentation exists for this element. -- Early Retirement Program Expense [Domain] Early Retirement Program Expense [Domain] -- None. No documentation exists for this element. -- Special Incentive Program [Member] Special Incentive Program [Member] Special Incentive Program [Member] Separation Incentive Program [Member] Separation Incentive Program [Member] Separation Incentive Program [Member] Voluntary Retirement Incentive Program [Member] Voluntary Retirement Incentive Program [Member] -- None. No documentation exists for this element. -- Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Defined Benefit Plan Assets Total [Member] Defined Benefit Plan Assets Total [Member] -- None. No documentation exists for this element. -- Concentration Risk by Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Concentration In Single Entity, Type Of Industry, Foreign Country Or Individual Fund [Member] Concentration In Single Entity, Type Of Industry, Foreign Country Or Individual Fund [Member] Concentration In Single Entity, Type Of Industry, Foreign Country Or Individual Fund [Member] Geographic Concentration [Member] Geographic Concentration Risk [Member] Single Equity Concentration [Member] Single Equity Concentration [Member] Information about an entity's defined benefit plan's significant investment concentrations in either a single entity, type of industry, foreign country and/or individual fund. Defined Benefit Plan by Plan Asset Categories [Axis] Defined Benefit Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Domain] Defined Benefit Plan, Plan Assets, Category [Domain] Foreign Investments [Member] Foreign Investments [Member] Information about the entity's defined pension plan foreign investments. Fixed income securities [Member] Fixed Income Securities [Member] Equity securities [Member] Equity Securities [Member] Equity funds [Member] Equity Funds [Member] Schedule Of Marketable Securities Equity Securities Investee Name [Axis] Schedule Of Marketable Securities Equity Securities Investee Name [Axis] -- None. No documentation exists for this element. -- Marketable Securities Equity Securities Investee, Name [Domain] Marketable Securities Equity Securities Investee, Name [Domain] -- None. No documentation exists for this element. -- Berkshire Hathaway Common Stock [Member] Berkshire Hathaway Common Stock [Member] Berkshire Hathaway Common Stock [Member] Defined Benefit Plan Health Care Cost Trend Groups [Axis] Defined Benefit Plan Health Care Cost Trend Groups [Axis] Defined Benefit Plan Health Care Cost Trend Groups [Axis] Defined Benefit Plan Health Care Cost Trend Groups [Domain] Defined Benefit Plan Health Care Cost Trend Groups [Domain] Defined Benefit Plan Health Care Cost Trend Groups [Domain] Pre-Age 65 [Member] Pre-Age 65 [Member] Pre-Age 65 [Member] Post-Age 65 [Member] Post Age 65 [Member] Post Age 65 [Member] Medicare Advantage [Member] Medicare Advantage [Member] Medicare Advantage [Member] Multiemployer Plan Type [Axis] Multiemployer Plan Type [Axis] Multiemployer Plans Type [Domain] Multiemployer Plans Type [Domain] Multiemployer Pension Plans [Member] Multiemployer Plans, Pension [Member] Retirement Benefits Disclosure [Line Items] Retirement Benefits Disclosure [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Settlement Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement Accumulated benefit obligation Defined Benefit Plan, Accumulated Benefit Obligation Company contributions Defined Benefit Plan, Plan Assets, Contributions by Employer Estimated employer contributions in next fiscal year Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year Net Periodic Cost (Benefit) for the Year Curtailment Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment Percent of Plan Assets Managed Internally by Company Percent of Plan Assets Managed Internally by Company The percentage of plan assets managed internally by the Company. Percent Of Plan Assets Managed By Investment Companies Percent Of Plan Assets Managed By Investment Companies The percentage of plan assets managed by investment companies. Number of investment companies actively managing plan assets Number Of Investment Companies Managing Plan Assets The number of investment companies actively managing plan assets. Defined benefit plan, target allocation maximum percentage of assets, singular equity security, without prior approval by plan administrator Defined Benefit Plan Target Allocation Percentage Of Assets Singular Equity Security Limit Without Approval Of Plan Administrator Target allocation maximum percentage of investment in a single equity security to total plan assets without prior approval of plan administrator. Defined benefit plan, target allocation percentage of assets Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Minimum percentage of plan assets considered as significant concentrations in pension plans Concentration Risk, Percentage Number of investments the company's pension plan held which individually exceed 10% of total plan assets Number Of Investments Companys Pension Plan Held Which Individually Exceed 10 Percent Of Total Plan Assets Number Of Investments The Companys Pension Plan Held Which Individually Exceed 10 Percent Of Total Plan Assets Value of investments Investments Percentage of total plan assets Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage Discount rate to determine benefit obligation Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Assumed health care cost trend rate Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year Direction of change for assumed health care cost trend rate Defined Benefit Plan, Assumed Health Care Cost Trend Rate, Description Ultimate health care cost trend rate Defined Benefit Plan, Ultimate Health Care Cost Trend Rate Year that rate reaches ultimate trend rate Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate Discount rate to determine periodic cost Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Number of multiemployer plans contributed to Number Of Multiemployer Plans Contributed To Number of multiemployer pension plans to which the Company contributed. Contributions to multiemployer pension plans Multiemployer Plan, Contributions by Employer Expense associated with the retirement benefits provided under incentive savings plans Defined Contribution Plan, Cost Inventories and Contracts in Progress [Abstract] Inventories and Contracts in Progress [Abstract] Inventories and Contracts in Progress Inventory Disclosure [Text Block] Debt Disclosure [Abstract] Debt Debt Disclosure [Text Block] Graham Healthcare Group [Member] Graham Healthcare Group [Member] Graham Healthcare Group [Member] Test Preparation [Member] Test Preparation [Member] Test Preparation [Member] Professional (U.S.) [Member] Kaplan Professional [Member] Kaplan Professional [Member] Goodwill [Roll Forward] Goodwill [Roll Forward] Goodwill, beginning balance Goodwill, Gross Accumulated impairment losses, beginning balance Goodwill, Impaired, Accumulated Impairment Loss Goodwill, net, beginning balance Measurement period adjustment Goodwill, Purchase Accounting Adjustments Acquisitions Goodwill, Acquired During Period Impairment Dispositions Goodwill, Written off Related to Sale of Business Unit Foreign currency exchange rate changes Goodwill, Foreign Currency Translation Gain (Loss) Goodwill, ending balance Accumulated impairment losses, ending balance Goodwill, net, ending balance Other Comprehensive Income (Loss) [Table] Other Comprehensive Income (Loss) [Table] Other Comprehensive Income (Loss) [Table] Equity Components [Axis] Foreign Currency Translation Adjustment [Member] Curtailments and settlements Included in Net Income [Member] Other Comprehensive Income (Loss) [Line Items] Other Comprehensive Income (Loss) [Line Items] [Line Items] for Other Comprehensive Income (Loss) [Table] Other Comprehensive Income (Loss), before Reclassifications, before Tax Other Comprehensive Income (Loss), before Reclassifications, before Tax Other Comprehensive Income (Loss) before Reclassifications, Tax Other Comprehensive Income (Loss) before Reclassifications, Tax Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax Reclassification from AOCI, Current Period, Tax Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Other Comprehensive Income (Loss), Before Tax Other Comprehensive Income (Loss), before Tax Other Comprehensive Income (Loss), Income Tax Other Comprehensive Income (Loss), Tax Other Comprehensive Income (Loss), Net of Tax Other Comprehensive Income (Loss), Net of Tax Revenue from Contracts with Customers Revenue from Contract with Customer [Text Block] Investments Investment [Text Block] Defined Benefit Plans Disclosures Defined Benefit Plans Assumption [Axis] Defined Benefit Plans Disclosures Defined Benefit Plans Assumption [Axis] Reflects the description and required disclosures pertaining to the entity's defined benefits pension, by plan or groupings of similar plans. Defined Benefit Plans Disclosures Defined Benefit Plans Assumption [Domain] Defined Benefit Plans Disclosures Defined Benefit Plans Assumption [Domain] Defined Benefit Plans Disclosures Defined Benefit Plans Assumption [Domain] Periodic Cost [Member] Periodic Cost [Member] Periodic cost assumptions. Discount rate (percent) Expected return on plan assets (percent) Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets Rate of compensation increase (percent) Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase Cash balance interest crediting rate Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Weighted-Average Interest Crediting Rate Weighted-average interest crediting rate used to determine net periodic benefit cost of defined benefit plan. Plan includes, but is not limited to, cash balance and other defined benefit plans with promised interest crediting rate. Ultimate cash balance interest crediting rate Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Ultimate Weighted-Average Interest Crediting Rate Ultimate weighted-average interest crediting rate used to determine net periodic benefit cost of defined benefit plan. Plan includes, but is not limited to, cash balance and other defined benefit plans with promised interest crediting rate. Year that reaches ultimate cash balance interest crediting rate Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Year that Weighted-Average Interest Crediting Rate Reaches Ultimate Rate Year ultimate weighted-average interest crediting rate is expected to be reached, in CCYY format. Schedule of Inventories and Contracts in Progress Schedule of Inventory, Current [Table Text Block] Segment Reporting [Abstract] Schedule of Restructuring and Related Costs [Table] Schedule of Restructuring and Related Costs [Table] Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] Accelerated depreciation Restructuring and Related Cost, Accelerated Depreciation Lease obligation losses Restructuring Reserve Lease Obligation Losses Amount of lease obligations charged against earnings associated with exit from or disposal of business activities or restructuring plan. Severance Severance Costs Other Other Restructuring Costs Total restructuring costs Restructuring Charges Deferred Income Tax Liabilities [Table] Deferred Income Tax Liabilities [Table] Deferred Income Tax Liabilities [Table] Pension Plan [Member] Deferred Income Tax Liabilities [Line Items] Deferred Income Tax Liabilities [Line Items] [Line Items] for Deferred Income Tax Liabilities [Table] Employee benefit obligations Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits Accounts receivable Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts State income tax loss carryforwards Deferred Tax Assets, Operating Loss Carryforwards, State and Local Capital loss carryforwards Deferred Tax Assets, Capital Loss Carryforwards U.S. Federal income tax loss carryforwards Deferred Tax Assets, Operating Loss Carryforwards, Domestic U.S Federal foreign income tax credit carryforwards Deferred Tax Assets, Tax Credit Carryforwards, Foreign Non-U.S. income tax loss carryforwards Deferred Tax Assets, Operating Loss Carryforwards, Foreign Other Deferred Tax Assets, Tax Deferred Expense, Other Deferred tax assets Deferred Tax Assets, Gross Valuation allowance Deferred Tax Assets, Valuation Allowance Deferred tax assets, net Deferred Tax Assets, Net of Valuation Allowance Prepaid pension cost Deferred Tax Liabilities, Prepaid Expenses Unrealized gain on available-for-sale securities Deferred Tax Liabilities, Unrealized Gains on Available-for-sale Securities Amount of deferred tax liability attributable to taxable temporary differences from unrealized gains on available-for-sale securities. Goodwill and other intangible assets Deferred Tax Liabilities, Goodwill and Intangible Assets Property, plant and equipment Deferred Tax Liabilities, Property, Plant and Equipment Non-U.S. withholding tax Deferred Tax Liabilities, Undistributed Foreign Earnings Deferred tax liabilities Deferred Tax Liabilities, Gross Deferred Income Tax Liabilities, Net Deferred Income Tax Liabilities, Net Contingencies Commitments and Contingencies Disclosure [Text Block] Accounting Policies [Abstract] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Domain] Initial Application Period Cumulative Effect Transition [Domain] Difference between Revenue Guidance in Effect before and after Topic 606 [Member] Difference between Revenue Guidance in Effect before and after Topic 606 [Member] Calculated under Revenue Guidance in Effect before Topic 606 [Member] Calculated under Revenue Guidance in Effect before Topic 606 [Member] Retained Earnings [Member] Retained Earnings [Member] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2016-01 [Member] Accounting Standards Update 2016-01 [Member] Accounting Standards Update 2014-09 [Member] Accounting Standards Update 2014-09 [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Revenues Costs and Expenses Cumulative Effect of New Accounting Principle in Period of Adoption Cumulative Effect of New Accounting Principle in Period of Adoption Fair Value Measurements Fair Value Disclosures [Text Block] Components of Debt Schedule of Long-term Debt Instruments [Table Text Block] Income Statement [Abstract] Total Operating Costs and Expenses Income from Operations Debt extinguishment costs Loss on marketable equity securities, net Income Before Income Taxes Net Income Net Income Attributable to Noncontrolling Interests Net Income (Loss) Attributable to Parent Debt [Table] Debt [Table] Schedule of all debt, including both short term and long term. Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] 5.75% Unsecured Notes due June 1, 2026 [Member] Five Point Seven Five Percent Unsecured Notes due June 1, 2026 [Member] Five Point Seven Five Percent Unsecured Notes due June 1, 2026 [Member] 7.25% Unsecured Notes due February 1, 2019 [Member] Seven Point Two Five Percent Unsecured Notes Due February One Two Thousand And Nineteen [Member] Seven Point Two Five Percent Unsecured Notes due February One, Two Thousand and Nineteen [Member] Kaplan Four Year Credit Agreement Dated July 14, 2016 [Member] Kaplan Four Year Credit Agreement Dated July 14, 2016 [Member] Kaplan Four Year Credit Agreement Dated July 14, 2016 [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Unsecured notes Unsecured Debt Line of Credit Long-term Line of Credit Other indebtedness Other Long-term Debt Total Debt Debt, Long-term and Short-term, Combined Amount Less: current portion Total Long-Term Debt Unamortized debt issuance costs Debt Issuance Costs, Net Activity Related to Stock Awards Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block] Activity Related to Stock Options Share-based Compensation, Stock Options, Activity [Table Text Block] Information related to Stock Options Outstanding and Exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding and Exercisable [Table Text Block] Fair Value of Options Assumptions Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Summary of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Antidilutive Weighted Average Restricted Stock and Options [Table Text Block] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Income Taxes [Table] Income Taxes [Table] -- None. No documentation exists for this element. -- Income Taxes [Line Items] Income Taxes [Line Items] Income Taxes [Line Items] U.S. Federal taxes at statutory rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount State and local taxes, net of U.S. Federal tax Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Valuation allowance against tax benefits Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount Stock based compensation Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Benefit, Amount Goodwill impairments and dispositions Effective Income Tax Rate Reconciliation, Impairment Losses and Disposition of Business Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to nondeductible impairment loss and the disposition of a business not qualifying as a discontinued operation. U.S. Federal Manufacturing Deducation tax benefits Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Amount Write-off of deferred taxes related to intercompany loans Income Tax Reconciliation Deferred Tax Assets Write-off Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to a deferred tax asset or liability write-off. Deferred tax impact of U.S. Federal tax rate reduction to 21%, net of state tax impact Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Deferred tax benefit on unremitted non-U.S. subsidiary earnings Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount Other, net Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Total provision for income tax Schedule of Earnings Per Share, Basic and Diluted, Including Two Class Method [Table] Schedule of Earnings Per Share, Basic and Diluted, Including Two Class Method [Table] Disclosures pertaining to an entity's basic and diluted earnings per share. Employee Stock Option [Member] Schedule of Earnings Per Share, Basic and Diluted, Including Two Class Method [Line Items] Schedule of Earnings Per Share, Basic and Diluted, Including Two Class Method [Line Items] [Line Items] for Disclosures pertaining to an entity's basic and diluted earnings per share. Net income attributable to Graham Holdings Company common stockholders Less: Dividends paid–common stock outstanding and unvested restricted shares Dividends Paid Common Stock And Share-based Compensation-Cash Amount of paid and unpaid common stock dividends declared with the form of settlement in cash and amount of paid and unpaid cash dividends declared and applicable to holders of share-based compensation, for example, but not limited to, non-vested shares, stock options, or restricted stock units. Undistributed earnings Undistributed Earnings, Basic Percent allocated to common stockholders Percentage Of Undistributed Earnings Allocated To Common Stockholders Represents the percentage allocation of undistributed earnings to common stockholders. Undistributed earnings allocated to common stockholders Undistributed Earnings Allocated To Common Stockholders The earnings that is allocated to common stock to the extend that each stockholder may share in the earnings as if all the earnings for the period has been distributed. Add: Dividends paid–common stock outstanding Dividends, Common Stock, Cash Numerator for basic earnings per share Net Income (Loss) Available to Common Stockholders, Basic Add: Additional undistributed earnings due to dilutive stock options Additional Undistributed Earnings Due To Dilutive Stock Options The earnings that is allocated to common stock due to the dilutive effect of stock options in diluted earnings per share. Numerator for diluted earnings per share Net Income (Loss) Available to Common Stockholders, Diluted Add: Effect of dilutive stock options (shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Denominator for diluted earnings per share (shares) Weighted Average Number of Shares Outstanding, Diluted Income Per Share From Continuing Operations To Common Stockholders [Abstract] Income Per Share From Continuing Operations To Common Stockholders [Abstract] Income Per Share From Continuing Operations To Common Shareholders. Earnings Per Share, Diluted (in usd per share) Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Indefinite-lived Intangible Assets [Axis] Indefinite-lived Intangible Assets [Axis] Indefinite-lived Intangible Assets, Major Class Name [Domain] Indefinite-lived Intangible Assets, Major Class Name [Domain] Trade name [Member] Trade Names [Member] Other [Member] Other Intangible Assets [Member] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Student and Customer Relationships [Member] Customer Relationships [Member] Trade Names and Trademarks [Member] Trademarks and Trade Names [Member] Databases and Technology [Member] Database Rights [Member] Non-compete Agreements [Member] Noncompete Agreements [Member] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Hoover Treated Wood Products [Member] Hoover Treated Wood Products [Member] Hoover Treated Wood Products [Member] Red Marker [Member] Red Marker [Member] Red Marker [Member] Series of Individually Immaterial Business Acquisitions [Member] Series of Individually Immaterial Business Acquisitions [Member] Genesis [Member] Genesis [Member] Genesis [Member] Hometown Home Health and Hospice [Member] Hometown Home Health and Hospice [Member] Hometown Home Health and Hospice Auto dealerships [Member] Auto dealerships [Member] Auto dealerships Business Acquisition [Line Items] Business Acquisition [Line Items] Debt Instrument, Term Debt Instrument, Term Document Fiscal Year Focus Document Fiscal Year Focus Accounts receivable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables Inventory Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory Property, plant and equipment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Goodwill Indefinite-lived intangible assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Indefinite-Lived Intangible Assets Amortized intangible assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles Other assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Assets Amount of other assets acquired at the acquisition date. Pension and other post retirement benefits liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Pension and Other Post Retirement Benefits Liabilities Amount of pension and postretirement liabilities assumed at the acquisition date. Other liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Deferred income tax liability Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Redeemable noncontrolling interest Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value Aggregate purchase price, net of cash received Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest, Net Of Cash Received Amount recognized as of the acquisition date for the assets, including goodwill, in excess of (less than) the aggregate liabilities assumed, less the noncontrolling interest in the acquiree, net of cash received. Income (Loss) from Continuing Operations before Income Taxes [Abstract] Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest [Abstract] U.S. Income (Loss) from Continuing Operations before Income Taxes, Domestic Non-U.S. Income (Loss) from Continuing Operations before Income Taxes, Foreign Statement of Stockholders' Equity [Abstract] Common Stock [Member] Common Stock [Member] Capital in Excess of Par Value [Member] Additional Paid-in Capital [Member] AOCI Attributable to Parent [Member] AOCI Attributable to Parent [Member] Treasury Stock [Member] Treasury Stock [Member] Noncontrolling Interest [Member] Noncontrolling Interest [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] As of Net income for the year Acquisition of redeemable noncontrolling interest Equity Effect of Acquisition of Redeemable Noncontrolling Interest Equity Effect of Acquisition of Redeemable Noncontrolling Interest Net income attributable to noncontrolling interest Net Income (Loss) Attributable to Noncontrolling Interest Net income attributable to redeemable noncontrolling interests Net Income (Loss) Attributable to Redeemable Noncontrolling Interest Change in redemption value of redeemable noncontrolling interests Noncontrolling Interest, Change in Redemption Value Dividends paid on common stock Dividends, Common Stock Repurchase of Class B common stock Treasury Stock, Value, Acquired, Cost Method Issuance of Class B common stock, net of restricted stock award forfeitures Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Amortization of unearned stock compensation and stock option expense Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Reclassification From Accumulated Other Comprehensive Income To Retained Earnings Tax Cuts and Jobs Act 2017, Reclassification From Accumulated Other Comprehensive Income To Retained Earnings Amount of reclassification adjustments of stranded tax effects from accumulated other comprehensive income to retained earnings as a result of tax reform. Cumulative effect of accounting change Other Stockholders' Equity, Other Other comprehensive income (loss), net of tax Other Comprehensive Income (Loss), Net of Tax, Non-spinoff related Amount after tax and reclassification adjustments of other comprehensive income (loss) not related to a spin-off.. Taxes arising from employee stock plans Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation Purchase of redeemable noncontrolling interest Equity effect of purchase of redeemable noncontrolling interest The equity effect of the purchase of redeemable noncontrolling interest Exchange of redeemable noncontrolling interest Exchange of Redeemable Noncontrolling Interest Effect of exchanging a redeemable noncontrolling interest for a mandatorily redeemable noncontrolling interest with entities under common control. As of Increase (Decrease) in Temporary Equity [Roll Forward] Increase (Decrease) in Temporary Equity [Roll Forward] As of Acquisition of redeemable noncontrolling interest Acquisition of Redeemable Noncontrolling Interest The fair value of the creation of a redeemable noncontrolling interest due to the acquisition of less than 100% of an entity. Net income attributable to redeemable noncontrolling interests Temporary Equity, Net Income Change in redemption value of redeemable noncontrolling interests Temporary Equity, Change in Redemption Value Change in temporary equity during the period as a result of a change in the redemption value of redeemable noncontrolling interest. Other Temporary Equity, Other Changes Purchase of redeemable noncontrolling interest Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests Exchange of redeemable noncontrolling interest Conversion of Redeemable Noncontrolling Interest The effect on the conversion of redeemable noncontrolling interest to mandatorily redeemable noncontrolling interest. As of Prospective Adoption of New Accounting Pronouncements [Table] Prospective Adoption of New Accounting Pronouncements [Table] Accounting Standards Update 2017-07 [Member] Accounting Standards Update 2017-07 [Member] Restatement [Axis] Restatement [Axis] Restatement [Domain] Restatement [Domain] Previously Reported [Member] Previously Reported [Member] Restatement Adjustment [Member] Restatement Adjustment [Member] Item Effected [Line Items] Item Effected [Line Items] Operating expenses Selling, general and administrative expenses Changes in Carrying Amount of Goodwill Schedule of Goodwill [Table Text Block] Other Intangible Assets Schedule of Finite and Indefinite Lived Intangible Assets [Table Text Block] Schedule of Finite and Indefinite Lived Intangible Assets [Table Text Block] Income Taxes Income Tax Disclosure [Text Block] Allowance for doubtful accounts[Member] SEC Schedule, 12-09, Allowance, Credit Loss [Member] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] Additions - Charged to Costs and Expenses SEC Schedule, 12-09, Valuation Allowances and Reserves, Additions, Charge to Cost and Expense Accounts Receivable, Net [Abstract] Accounts Receivable, Net [Abstract] Receivables from contracts with customers, less doubtful accounts Accounts Receivable, Net, Current Other receivables Other Receivables Accounts receivable, net Allowance for Doubtful Accounts Receivable Allowance for Doubtful Accounts Receivable Accounts Payable, Current [Abstract] Accounts Payable, Current [Abstract] Accounts payable and accrued liabilities Accounts Payable and Other Accrued Liabilities, Current Accrued compensation and related benefits Employee-related Liabilities, Current Total accounts payable and accrued liabilities Deferred Revenue Deferred Revenue Deferred Revenue, Period Decrease Percentage Deferred Revenue, Period Increase (Decrease) Percentage Deferred Revenue, Period Increase (Decrease) Percentage Property, Plant and Equipment Property, Plant and Equipment [Table Text Block] Goodwill and Other Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] 10-Year Borrowing to Finance Acquisition [Member] 10-Year Borrowing to Finance Acquisition [Member] 10-Year Borrowing to Finance Acquisition [Member] Schedule of Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Axis] Schedule of Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Axis] Financial Instruments Subject to Mandatory Redemption, Financial Instrument [Domain] Financial Instruments Subject to Mandatory Redemption, Financial Instrument [Domain] Securities Subject to Mandatory Redemption [Member] Securities Subject to Mandatory Redemption [Member] Other Businesses [Member] Group Dekko [Member] Group Dekko [Member] Group Dekko [Member] SocialCode [Member] SocialCode [Member] SocialCode [Member] Professional (U.S.) [Member] Professional (U.S.) [Member] Professional (U.S.) [Member] Period of Transition Operations and Support Agreement [Axis] Period of Transition Operations and Support Agreement [Axis] Period of Transition Operations and Support Agreement [Axis] Period of Transition Operations and Support Agreement [Domain] Period of Transition Operations and Support Agreement [Domain] [Domain] for Period of Transition Operations and Support Agreement [Axis] After June 30, 2048 [Member] After June 30, 2048 [Member] Period of time after June 30, 2048 (thirtieth year) for which the TOSA term applies After June 30, 2024 [Member] After June 30, 2024 [Member] Period of time after June 30, 2024 (7th year and beyond) for which the TOSA term applies After June 30, 2023 [Member] After June 30, 2023 [Member] Period of time after June 30, 2023 (6th year and beyond) for which the TOSA term applies After June 30, 2027 [Member] After June 30, 2027 [Member] Period of time after June 30, 2027 for which the TOSA term applies July 1, 2022 through June 30, 2027 [Member] July 1, 2022 through June 30, 2027 [Member] Period of time July 1, 2022 through June 30, 2027 for which the TOSA term applies (Years 5-9) March 22, 2018 through June 30, 2022 [Member] March 22, 2018 through June 30, 2022 [Member] Period of time March 22, 2018 through June 30, 2022 for which the TOSA term applies (first 4 years) March 22, 2018 through June 30, 2023 [Member] March 22, 2018 through June 30, 2023 [Member] Period of time March 22, 2018 through June 30, 2023 for which the TOSA term applies (first 5 years) Recipient of Consideration [Axis] Recipient of Consideration [Axis] Recipient of Consideration Recipient of Consideration [Domain] Recipient of Consideration [Domain] [Domain] for Recipient of Consideration Kaplan [Member] Kaplan [Member] Kaplan [Member] Purdue University Global [Member] Purdue University Global [Member] Purdue University Global Kaplan Australia [Member] Kaplan Australia [Member] Kaplan Australia [Member] Celtic Healthcare Inc [Member] Celtic Healthcare Inc [Member] -- None. No documentation exists for this element. -- Marketplace Strategy [Member] Marketplace Strategy [Member] Marketplace Strategy [Member] Mander Portman Woodward [Member] Mander Portman Woodward [Member] Mander Portman Woodward [Member] Osborne Books [Member] Osborne Books [Member] Osborne Books [Member] Electri-Cable Assemblies [Member] Electri-Cable Assemblies [Member] Electri-Cable Assemblies [Member] Furnlite Inc [Member] Furnlite Inc [Member] Furnlite Inc [Member] College for Financial Planning [Member] College for Financial Planning [Member] College for Financial Planning Professional Publications, Inc. [Member] Professional Publications, Inc. [Member] Professional Publications, Inc. Percentage Of Joint Venture Sold Percentage Of Joint Venture Sold The percentage of a joint venture sold. Cost of acquisition Business Combination, Consideration Transferred Derivative, Fixed Interest Rate Derivative, Fixed Interest Rate Pension and other post retirement benefits liabilities Number of businesses acquired Number of Businesses Acquired Amount Borrowed to Finance Business Acquisition Amount Borrowed to Finance Business Acquisition Amount Borrowed to Finance Business Acquisition Percentage of interest acquired Business Acquisition, Percentage of Voting Interests Acquired Payments to Acquire Businesses, Net of Cash Acquired Acquisition-related costs Business Acquisition, Transaction Costs Goodwill expected to be deductible for income tax purposes Business Acquisition, Goodwill, Expected Tax Deductible Amount Revenues of acquired companies since acquisition date Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual Operating loss of acquired companies since acquisition date Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual Noncontrolling interest purchased Noncontrolling Interest Purchased Percent of noncontrolling interest purchased during the period. Noncontrolling Interest, Ownership Percentage by Parent Noncontrolling Interest, Ownership Percentage by Parent Redeemable Noncontrolling Interest, Equity, Common, Redemption Value Redeemable Noncontrolling Interest, Equity, Common, Redemption Value Noncontrolling interest exchanged Noncontrolling Interest Exchanged The percentage of redeemable noncontrolling interest exchanged. Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Payments to acquire businesses per agreement Payments To Acquire Businesses Per Agreement The payments to be paid to acquire businesses per agreement. Number of business lines Number of Business Lines The number of business lines. Transition and Operations Support Agreement Initial Term Transition and Operations Support Agreement Initial Term Transition and Operations Support Agreement Initial Term Transition and Operations Support Agreement Buy-Out Option Eligible Year Transition and Operations Support Agreement Buy-Out Option Eligible Year Transition and Operations Support Agreement Buy-Out Option Eligible Year Transition and Operations Support Agreement Renewal Periods Transition and Operations Support Agreement Renewal Periods Transition and Operations Support Agreement Renewal Periods after initial 30 year term Gain (Loss) on Disposition of Business Percentage of Cost Efficiencies Percentage of Cost Efficiencies Percentage of Cost Efficiencies to be used to Calculate Additional Efficiency Payment First Five Years of Transition and Operations Support Agreement First Five Years of Transition and Operations Support Agreement First five years of TOSA Amount of Priority Payment Per Year Beyond Costs Amount of Priority Payment Per Year Beyond Costs Amount of priority payment made to Purdue University Global beyond costs before any payment to Kaplan Advance Related To Kaplan University Transaction Advance Related To Kaplan University Transaction Advance related to Kaplan University Transaction. Kaplan Share of Purdue University Global Revenue Kaplan Share of Purdue University Global Revenue Percentage representing Kaplan's fee based on Purdue University Global Revenue Percentage of Revenue Remaining To Be Paid Percentage of Revenue Remaining To Be Paid Percentage of Purdue University Global Revenue remaining after Kaplan Efficiency Payment and other adjustments paid to Purdue University Global Kaplan University Transaction Termination Fee Kaplan University Transaction Termination Fee Percent of Purdue Global University revenue for preceding 12 month period to be paid to terminate the Transition and Operations Support Agreement Purdue University Global Final Payment Note Duration Purdue University Global Final Payment Note Duration Duration of note for final payment made by Purdue University Global to Kaplan upon termination of TOSA Annual Purdue University Global Cash Operating Losses Annual Purdue University Global Cash Operating Losses Annual Purdue University Global cash operating losses threshold for option to terminate Transition and Operations Support Agreement Aggregate Purdue University Global Cash Operating Losses Aggregate Purdue University Global Cash Operating Losses Aggregate Purdue University Global cash operating losses threshold for option to terminate Transition and Operations Support Agreement Number of Consecutive Years of Purdue University Global Cash Operating Losses Number of Consecutive Years of Purdue University Global Cash Operating Losses Number of consecutive years of Purdue University Global cash operating losses for option to terminate Transition and Operations Support Agreement Fair value of redeemable noncontrolling interest acquired Business Combination Acquisition Of Less than 100 Percent Redeemable Noncontrolling Interest Fair Value This element represents the fair value of the redeemable noncontrolling interest in the acquiree at the acquisition date. Term of loan entered into to finance business combination Term of Loan Entered into to Finance Business Combination the term of a loan entered into to finance a business combination. Summary of Other Comprehensive Income (Loss) Comprehensive Income (Loss) [Table Text Block] Summary of Changes in Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Summary of Amounts and Line Items of Reclassifications out of Accumulated Other Comprehensive Income (Loss) Disclosure of Reclassification Amount [Text Block] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Beginning of year, unvested, Number of Shares Awarded, Number of Shares Vested, Number of Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Forfeited, Number of Shares End of year, unvested, Number of Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Beginning of year, Average Grant-Date Fair Value (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Awarded, Average Grant-Date Fair Value (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Vested, Average Grant-Date Fair Value (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Forfeited, Average Grant-Date Fair Value (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value End of year, Average Grant-Date Fair Value (in dollars per share) 2019 Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months 2020 Defined Benefit Plan, Expected Future Benefit Payment, Year Two 2021 Defined Benefit Plan, Expected Future Benefit Payment, Year Three 2022 Defined Benefit Plan, Expected Future Benefit Payment, Year Four 2023 Defined Benefit Plan, Expected Future Benefit Payment, Year Five 2024-2028 Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter Raw materials Inventory, Raw Materials, Net of Reserves Work-in-process Inventory, Work in Process, Net of Reserves Finished goods Inventory, Finished Goods, Net of Reserves Contracts in Progress Inventory for Long-term Contracts or Programs, Gross Inventories and contracts in progress Total cost Equity Securities, FV-NI, Cost Total cost Available-for-sale Equity Securities, Amortized Cost Basis Gross unrealized gains Equity Securities FV-NI, Accumulated Gross Unrealized Gain Amount of unrealized gain on investment on equity security measured at fair value with change in fair value recognized in net income (FV-NI). Gross unrealized gains Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax Gross unrealized losses EquitySecuritiesFVNIAccumulatedGrossUnrealizedLoss Amount of unrealized loss on investment on equity security measured at fair value with change in fair value recognized in net income (FV-NI). Gross unrealized losses Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax Total Fair Value Total Fair Value Schedule of Income Before Income Taxes, Domestic and Foreign Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block] Schedule of Provision for Income Taxes on Income Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of Effective Income Tax Rate Reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule of Deferred Tax Assets and Liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Schedule of Income Tax Loss Carryforwards Summary of Operating Loss Carryforwards [Table Text Block] Schedule of Changes in Deferred Tax Valuation Allowance Summary of Valuation Allowance [Table Text Block] Schedule of Unrecognized Tax Benefits Roll Forward Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block] Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Disposal Group, Not Discontinued Operation, Revenue Disposal Group, Not Discontinued Operation, Revenue Amount of revenue attributable to disposal group. Excludes discontinued operations. Disposal Group, Not Discontinued Operation, Operating Income Disposal Group, Not Discontinued Operation, Operating Income (Loss) Amount of operating income (loss) attributable to disposal group. Excludes discontinued operations. Schedule of Accounts Receivable Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Schedule of Changes in Allowance for Doubtful Accounts Schedule Of Changes In Allowance For Doubtful Accounts And Returns Allowance For Advertising Rate Adjustments And Discounts [Table Text Block] Tabular disclosure of Changes in Allowance for Doubtful Accounts and Returns Allowance for Advertising Rate Adjustments and Discounts Schedule of Accounts Payable and Accrued Liabilities Schedule of Accounts Payable and Accrued Liabilities [Table Text Block] Schedule of Prospective Adoption of New Accounting Pronouncements Schedule of Prospective Adoption of New Accounting Pronouncements [Table Text Block] Schedule of New Accounting Pronouncements and Changes in Accounting Principles Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block] Accumulated Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward] Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward] Fair value of assets at beginning of year Defined Benefit Plan, Plan Assets, Amount Purchases, sales and settlements, net Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Purchase, Sale, and Settlement Gains relating to assets sold Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Actual Return (Loss) on Plan Assets Sold (Losses) gains relating to assets still held at year-end Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Actual Return (Loss) on Plan Assets Still Held Fair value of assets at end of year Expected life (in years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Interest rate, minimum Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum Interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Interest rate, maximum Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Maximum Volatility, minimum (percentage) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum Volatility (percentage) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Volatility, maximum (percentage) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum Dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table] Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table] Common Class B [Member] Exercise Price Range of $244-$276 [Member] Price Range One [Member] Exercise Price Range of $244-276 Exercise Price $325 [Member] Price Range Two [Member] Exercise Price of $325 Exercise Price $719 [Member] Price Range Three [Member] Exercise Price of $719 Exercise Price Range of $805-$872 [Member] Price Range Four [Member] Exercise Price of $805-872 Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] Low Exercise Price Range Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit High Exercise Price Range Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit Options Outstanding, Shares Outstanding Options Outstanding, Weighted Average Remaining Contractual Life (in years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Options Outstanding, Weighted Average Exercise Price (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Options Exercisable, Shares Exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Options Exercisable, Weighted Average Remaining Contractual Life (in years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Options Exercisable, Weighted Average Exercise Price (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Expected return on assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Amortization of prior service cost (credit) Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Recognized actuarial loss (gain) Defined Benefit Plan, Amortization of Gain (Loss) Net Periodic Cost (Benefit) for the Year Curtailment Settlement Early retirement programs and special separation benefit expense Total Cost (Benefit) for the Year Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract] Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract] Current year actuarial gain (loss) Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax Current year prior service cost Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), before Tax Amortization of prior service credit (cost) Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax Recognized net actuarial gain (loss) Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax Curtailments and settlements Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax Total Recognized in Other Comprehensive Income (Before Tax Effects) Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax Total Recognized in Total (Benefit) Cost and Other Comprehensive Income (Before Tax Effects) Defined Benefit Plan, Amount Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Income) Loss, before Tax Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Network affiliation agreements [Member] Contract-Based Intangible Assets [Member] Amortized Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Useful Life (in years) Finite-Lived Intangible Asset, Useful Life Gross Carrying Amount Finite-Lived Intangible Assets, Gross Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Net Carrying Amount Schedule of Indefinite-Lived Intangible Assets [Table] Schedule of Indefinite-Lived Intangible Assets [Table] FCC licenses [Member] Operating and Broadcast Rights [Member] Licensure and Accreditation [Member] Licensure and Accreditation [Member] Licensure And Accreditation [Member] Indefinite-lived Intangible Assets [Line Items] Indefinite-lived Intangible Assets [Line Items] Net Carrying Amount Defined Benefit Plans [Member] Defined Benefit Plans [Member] Defined benefit plans consisting of various pension plans and a Supplemental Executive Retirement Plan (SERP). Benefit Obligation [Member] Benefit Obligation [Member] Benefit obligation assumptions. Schedule of Obligation, Asset and Funding Information Schedule of Net Funded Status [Table Text Block] Schedule of Amounts Recognized in Balance Sheet Schedule of Amounts Recognized in Balance Sheet [Table Text Block] Schedule of Assumptions Used Schedule of Assumptions Used [Table Text Block] Schedule of Estimated Benefit Payments Schedule of Expected Benefit Payments [Table Text Block] Schedule of Net (Benefit) Costs Schedule of Net Benefit Costs [Table Text Block] Schedule of Amounts Recognized in Accumulated Other Comprehensive Income (Loss) Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block] Allocation of the Assets of the Company's Pension Plans Schedule of Allocation of Plan Assets [Table Text Block] Fair Value, Assets Measured on Recurring Basis Fair Value, Assets Measured on Recurring Basis [Table Text Block] Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets [Table Text Block] Tax Credit Carryforward [Axis] Tax Credit Carryforward [Axis] Tax Credit Carryforward, Name [Domain] Tax Credit Carryforward, Name [Domain] Capital loss carryforwards to 2013 tax year [Member] Capital Loss Carryforwards To 2013 Tax Year [Member] Capital loss carryforwards to the 2013 tax year [Member] Capital loss carryforward [Member] Capital Loss Carryforward [Member] U.S. Federal and State [Member] Domestic And State [Member] -- None. No documentation exists for this element. -- Australian Taxation Office [Member] Australian Taxation Office [Member] Carryforwards Period [Axis] Carryforward Period [Domain] Through 2023 [Member] Loss Carryforwards Expirations Range One [Member] -- None. No documentation exists for this element. -- After 2023 [Member] Loss Carryforwards Expirations Range Two [Member] -- None. No documentation exists for this element. -- Adjustment [Member] Scenario, Adjustment [Member] Internal Revenue Service (IRS) [Member] Internal Revenue Service (IRS) [Member] Tax Act [Axis] Tax Act [Axis] Tax Act [Axis] Tax Act [Domain] Tax Act [Domain] [Domain] for Tax Act [Axis] Reduction In Federal Tax Rate [Member] Reduction In Federal Tax Rate [Member] Reduction In Federal Tax Rate [Member] Change in Tax on non-US Subsidiary Earnings [Member] Change in Tax On Non-US Subsidiary Earnings [Member] Change in Non-US Subsidiary Earnings [Member] Income Tax Expense (Benefit), Adjustment of Deferred Tax (Asset) Liability Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability Deferred income tax expense (benefit) Deferred state income tax asset Income tax loss carryforwards obtained as a result of prior stock acqusitions Deferred tax assets with respect to U.S. Federal income tax loss carryforwards Foreign tax credit carryforwards Foreign Tax Credit Carryforwards Foreign tax credits available to be credited against future U.S. Federal income tax liabilities. Deferred tax assets with respect to U.S. Federal foreign tax credit carryforwards Tax loss carryforwards as a result of operating losses and prior stock acquisitions Operating Losses And Prior Stock Acqusitions Carryforward Tax loss carryforwards as a result of operating losses and prior stock acquisitions Deferred tax assets with respect to non U.S. income tax loss carryforwards Valuation allowance against the deferred tax assets recorded for the tax losses carryforward Deferred Tax Asset Operating Losses And Prior Stock Acquisitions Carryforward Valuation Allowance Valuation allowance against the deferred tax assets recorded for the tax losses carryforward. Tax loss carryforwards from operating losses and prior stock acquisitions that can be carried forward indefinitely Operating Losses And Prior Stock Acqusitions Carryforward Indefinitely Tax loss carryforwards from operating losses and prior stock acquisitions that can be carried forward indefinitely. Tax loss carryforwards subject to expiration Operating Losses And Prior Stock Acqusitions Carryforward Subject To Expiration Tax loss carryforward resulting from operating losses and prior stock acquisitions subject to expiration. Carryforward amount Tax Credit Carryforward, Amount Non-U.S.deferred tax asset related to capital loss carryforwards Valuation Allowance, Amount Valuation allowance related to operating loss carryforwards Operating Loss Carryforwards, Valuation Allowance Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount Deferred income tax liabilities related to undistributed earnings of investments in non-U.S. subsidiaries Excess of book value over tax basis of investment Excess Of Book Value Over Tax Basis Of Investment Excess of book value over tax basis of investment in non-U.S. subsidiaries. Valuation allowance released Refund from Settlement with Taxing Authority Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority Unrecognized tax benefit that would impact the effective tax rate Unrecognized Tax Benefits that Would Impact Effective Tax Rate Federal tax impact of unrecognized tax benefits that would impact the effective tax rate Federal Tax Impact Of Unrecognized Tax Benefits that Would Impact Effective Tax Rate The federal tax impact of the total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate. Interest accrued related to unrecognized tax benefits Unrecognized Tax Benefits, Interest on Income Taxes Accrued Penalties accrued related to unrecognized tax benefits Unrecognized Tax Benefits, Income Tax Penalties Accrued Schedule of Future Minimum Rental Payments for Operating Leases Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Discount rate (percent) Rate of compensation increase (percent) Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase Cash balance interest crediting rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Weighted-Average Interest Crediting Rate Weighted-average interest crediting rate used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, cash balance and other defined benefit plans with promised interest crediting rate. Ultimate cash balance interest crediting rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Ultimate Weighted-Average Interest Crediting Rate Ultimate weighted-average interest crediting rate used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, cash balance and other defined benefit plans with promised interest crediting rate. Year that reaches ultimate cash balance interest crediting rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Year Weighted-Average Interest Crediting Rate Reaches Ultimate Rate Year ultimate weighted-average interest crediting rate is expected to be reached, in CCYY format. Pro Forma Operating revenues Business Acquisition, Pro Forma Revenue Pro Forma Net income Business Acquisition, Pro Forma Net Income (Loss) Impairment of intangible assets Impairment of Intangible Assets, Finite-lived Number of businesses that recorded impairment of intangible and other long-lived assets Number of Businesses Recorded Impairment of Intangible And Other Long-Lived Assets Number of businesses that recorded impairment of intangible and other long-lived assets. Impairment of intangible and other long-lived assets Impairment Of Intangible And Other Long-Lived Assets The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of intangible and other long-lived assets. Amortization of Intangible Assets Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Estimated amortization of intangible assets, 2019 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months Estimated amortization of intangible assets, 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Two Estimated amortization of intangible assets, 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Three Estimated amortization of intangible assets, 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Four Estimated amortization of intangible assets, 2023 Finite-Lived Intangible Assets, Amortization Expense, Year Five Estimated amortization of intangible assets, after 2023 Finite-Lived Intangible Assets, Amortization Expense, after Year Five Business Segments Segment Reporting Disclosure [Text Block] Loss on guarantor obligations Net gain on cost method investments Foreign currency (loss) gain, net Gain on sale of cost method investments Cost-method Investments, Realized Gain (Loss) Impairment of cost method investments Equity Securities without Readily Determinable Fair Value, Impairment Loss, Annual Amount Impairment of cost method investment Net losses on sales or write-down of marketable equity securities Marketable Securities, Realized Gain (Loss) Other, net Other Nonoperating Gains (Losses) Other income (expense), net Preferred Stock, par value per share Preferred Stock, Par or Stated Value Per Share Preferred Stock, shares authorized Preferred Stock, Shares Authorized Preferred Stock, shares issued Preferred Stock, Shares Issued Common Stock, par value per share Common Stock, Par or Stated Value Per Share Common Stock, shares authorized Common Stock, Shares Authorized Common Stock, shares issued Common Stock, Shares, Issued Common Stock, shares outstanding Common Stock, Shares, Outstanding Treasury Stock Treasury Stock, Shares Schedule of Investments [Table] Schedule of Investments [Table] KIHL [Member] KIHL [Member] KIHL [Member] Markel Corporation [Member] MarkelCorporation [Member] Markel Corporation [Member] Intersection [Member] Intersection [Member] Intersection Holdings,LLC [Member] Residential Home Health Illinois [Member] Residential Home Health Illinois [Member] Residential Home Health Illinois [Member] Residential Hospice Illinois [Member] Residential Hospice Illinois [Member] Residential Hospice Illinois [Member] Two investments [Member] Two investments [Member] Two investments [Member] York Joint Venture [Member] York Joint Venture [Member] York Joint Venture [Member] HomeHero [Member] HomeHero [Member] HomeHero [Member] One Investment [Member] One Investment [Member] One Investment [Member] Schedule of Investments [Line Items] Schedule of Investments [Line Items] Number of shares held in investment Number Of Shares Held In Investment The number of shares held in an investment. Cash paid for new marketable equity securities Payments to Acquire Marketable Securities Marketable equity securities purchased Available For Sale Securities Equity Acquired Equity securities classified as available-for-sale securities acquired. Cumulative realized gain (loss) on marketable securities Proceeds from sales of marketable equity securities Proceeds from Sale and Maturity of Marketable Securities Loss on sales of marketable equity securities Marketable Securities, Realized Loss, Excluding Other than Temporary Impairments This item represents the total realized loss included in earnings for the period as a result of selling marketable securities categorized as trading, available-for-sale, or held-to-maturity. Gain on sales of marketable equity securities Marketable Securities, Realized Gain (Loss), Excluding Other-than-temporary Impairment Loss Revenue from Related Parties Revenue from Related Parties Loan commitment to affiliate Other Commitment Advances to Affiliate Advances to Affiliate Payments to Fund Long-term Loans to Related Parties Loan Receivable, Payment Term Loan Receivable, Payment Terms Description of the payment terms of the debt instrument (for example whether periodic payments include principal and frequency of payments) and discussion about any contingencies associated with the payment. Loan Receivable Fixed Interest Rate Related Party Transaction, Rate Equity Method Investment, Other than Temporary Impairment Equity Method Investment, Other than Temporary Impairment Equity Securities without Readily Determinable Fair Value, Amount Equity Securities without Readily Determinable Fair Value, Amount Impairment loss on cost method investments Quarterly Impact of Certain Items [Table] Quarterly Impact of Certain Items [Table] Quarterly Impact of Certain Items [Table] Other Businesses [Member] Other Businesses [Member] Other Businesses [Member] Quarterly Impact of Certain Items [Line Items] Quarterly Impact of Certain Items [Line Items] Quarterly Impact of Certain Items [Line Items] Impairment of Intangible Assets, After Tax Impairment of Intangible Assets, Net of Tax Impairment of intangible assets, After tax Earnings per Share, Diluted, Impairment Of Intangible Assets Earnings per Share, Diluted, Impairment Of Intangible Assets Earnings per Share, Diluted, Impairment of Intangible Assets Reduction to operating expenses in association with spectrum repack agreement Reduction to Operating Expenses In Association With Spectrum Repack Mandate, Net of Tax Reduction to operating expenses in association with spectrum repack mandate, after tax Earnings Per Share, Diluted, Reduction to operating expenses in association with spectrum repack agreement Earnings Per Share, Diluted, Reduction to Operating Expenses in Association with Spectrum Repack Agreement Earnings Per Share, Reduction to operating expenses in association with spectrum repack agreement Interest Expense, after tax Interest Expense, Net of Tax The amount of interest expense, after tax Earnings per share, diluted, interest expense Earnings Per Share, Diluted, Interest Expense Earnings per share, diluted, interest expense Debt extinguishment costs, after tax Debt Extinguishment Costs, Net of Tax Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity, after tax. Earnings per share, diluted, debt extinguishment costs Earnings Per Share, Diluted, Debt Extinguishment Costs Earnings per share, diluted, debt extinguishment costs Gain on Lump Sum Pension Settlement and curtailment of postretirement benefit plans, after tax Gain On Lump Sum Pension Settlement And Curtailment Of Postretirement Benefit Plans, Net of Tax Amount of gain (loss) recognized in net periodic benefit (cost) credit from irrevocable action relieving primary responsibility for benefit obligation and eliminating risk related to obligation and assets used to effect settlement, after tax. Earnings per share, diluted, settlement gain related to bulk lump sum pension offering and curtailment gain Earnings Per Share, Diluted, Settlement Gain Related To Bulk Lump Sum Pension Offering And Curtailment Gain Earnings per share, diluted, settlement gain related to bulk lump sum pension offering and curtailment gain (Loss) Gain on Marketable Equity Securities, after tax Gain (Loss) On Marketable Equity Securities, Net of Tax Amount of unrealized and realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income, after tax Earnings per share, diluted, (loss) gain on marketable equity securities Earnings Per Share, Diluted, Losses On Marketable Equity Securities Earnings per share, diluted, losses on marketable equity securities Non-operating gain from sales, write-ups and impairments of investments, and related to sales of land and businesses, including losses on guarantor obligations Non-Operating Gain From Sales, Write-ups And Impairments Of Investments, And Related To Sales Of Land And Businesses, Including Losses On Guarantor Obligations, Net of Tax Non-operating gain from sales, write-ups and impairments of investments, and related to sales of land and businesses, including losses on guarantor obligations, after tax Earnings per share, Diluted, non-operating gain from sales, write-ups and impairments of investments, and related to sales of businesses, including loss on guarantor obligations Earnings Per Share, Diluted, Non-operating Gain From Sales, Write-ups And Impairments Of Investments, And Related To Sales Of Businesses, Including Loss On Guarantor Obligations Earnings per share, Diluted, non-operating gain from sales, write-ups and impairments of investments, and related to sales of businesses, including loss on guarantor obligations Gain on Kaplan University transaction, after tax Gain (Loss) on Disposition of Business, Net of Tax Amount of gain (loss) from sale of disposal of integrated set of activities and assets capable of being conducted and managed for purpose of providing return in form of dividend, lower cost, or other economic benefit to investor, owner, member and participant. Earnings per share, diluted, gain from Kaplan University transaction Earnings Per Share, Diluted, Gain (Loss) on Disposition of Business Earnings per share, diluted, gain from Kaplan University transaction Non-operating unrealized foreign currency gains (losses), after tax Foreign Currency Transaction Gain (Loss), Unrealized, Net of Tax Foreign Currency Transaction Gain (Loss), After Tax Earnings Per Share, Diluted, Foreign Currency Transaction Gain (Loss), Unrealized Earnings Per Share, Diluted, Foreign Currency Transaction Gain (Loss), Unrealized Earnings Per Share, Diluted, Foreign Currency Transaction Gain (Loss), Unrealized Discrete Deferred Tax Benefit Discrete Deferred Tax Benefit A nonrecurring deferred tax benefit related to valuation allowances Earnings per share, Diluted, nonrecurring discrete deferred state tax benefit related to the release of valuation allowances Earnings Per Share, Diluted, Nonrecurring Discrete Deferred State Tax Benefit Related To The Release Of Valuation Allowances Earnings per share, Diluted, nonrecurring discrete deferred state tax benefit related to the release of valuation allowances Effective Income Tax Rate Reconciliation, Share-Based Compensation, Excess Tax Benefit Earnings Per Share, Diluted, Effective Income Tax Rate Reconciliation, Share-based Compensation Excess Tax Benefit Earnings Per Share, Diluted, Effective Income Tax Rate Reconciliation, Share-based Compensation Excess Tax Benefit Earnings Per Share, Diluted, Effective Income Tax Rate Reconciliation, share-based compensation, excess tax benefit amount Restructuring And Related Charges, Net of Tax Restructuring And Related Charges, Net of Tax Restructuring costs and related charges, including early retirement program expenses, after tax. Earnings Per Share, Diluted, Restructuring And Related Charges Earnings Per Share, Diluted, Restructuring And Related Charges Earnings Per Share, Diluted, Restructuring and Related Charges Goodwill and Other Long-Lived Asset Impairment, Net of Tax Impairment Of Goodwill And Other Long-Lived Assets, Net of Tax Goodwill and other long-lived asset impairment, after tax Earnings Per Share, Diluted, Goodwill And Other Long-Lived Assets Impairment, Net of Tax Earnings Per Share, Diluted, Impairment Of Goodwill And Other Long-Lived Assets Earnings Per Share, Diluted, Impairment Of Goodwill And Other Long-Lived Assets Net nonrecurring deferred tax benefit adjustment Net Deferred Tax Benefit Net nonrecurring deferred tax benefit adjustment. Earnings Per Share, Diluted, Net Deferred Tax Benefit Earnings Per Share, Diluted, Net Deferred Tax Benefit Net nonrecurring deferred tax benefit adjustment, per share. Prior Period Reclassification Adjustment Prior Period Reclassification Adjustment Schedule of Quantifying Prior Year Misstatement Corrected in Current Year Financial Statements [Table] Schedule of Quantifying Prior Year Misstatement Corrected in Current Year Financial Statements [Table] Prior Period Adjustments [Axis] Prior Period Adjustments [Axis] -- None. No documentation exists for this element. -- Prior Period Adjustments [Domain] Prior Period Adjustments [Domain] -- None. No documentation exists for this element. -- Periods from Q3 2016 to Q3 2017 [Member] Periods from Q3 2016 to Q3 2017 [Member] Periods from Q3 2016 to Q3 2017 [Member] [Member] Quantifying Misstatement in Current Year Financial Statements [Line Items] Quantifying Misstatement in Current Year Financial Statements [Line Items] Statement of Comprehensive Income [Abstract] Other Comprehensive (Loss) Income, Before Tax Other Comprehensive Income (Loss), before Tax [Abstract] Foreign currency translation adjustments: Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax, Portion Attributable to Parent [Abstract] Translation adjustments arising during the year Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax Adjustment for sales of businesses with foreign operations Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax Total foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax Unrealized gains on available-for-sale securities: Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax [Abstract] Unrealized gains for the year Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, before Tax Reclassification adjustment for realization of loss on sale of available-for-sale securities included in net income Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Total unrealized gains on available-for-sale securities Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax Pension and other postretirement plans: Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax [Abstract] Actuarial (loss) gain Prior service credit (cost) Amortization of net actuarial (gain) loss included in net income Amortization of net prior service (credit) cost included in net income Curtailments and settlements included in net income Total pension and other postretirement plans Cash flow hedge gain (loss) Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax Other Comprehensive (Loss) Income, Before Tax Income tax benefit (expense) related to items of other comprehensive (loss) income Other Comprehensive (Loss) Income, Net of Tax Comprehensive Income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive income attributable to noncontrolling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Total Comprehensive Income Attributable to Graham Holdings Company Summary of Other Non-Operating Income (Expense) Schedule of Other Nonoperating Income (Expense) [Table Text Block] Basis of Presentation and Principles of Consolidation Consolidation, Subsidiaries or Other Investments, Consolidated Entities, Policy [Policy Text Block] Reclassifications Reclassification, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Business Combinations Business Combinations and Other Purchase of Business Transactions, Policy [Policy Text Block] Cash and Cash Equivalents Cash and Cash Equivalents, Unrestricted Cash and Cash Equivalents, Policy [Policy Text Block] Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Concentration of Credit Risk Concentration Risk, Credit Risk, Policy [Policy Text Block] Allowance for Doubtful Accounts Trade and Other Accounts Receivable, Policy [Policy Text Block] Investments in Equity Securities Investment, Policy [Policy Text Block] Fair Value Measurements Fair Value Measurement, Policy [Policy Text Block] Fair Value of Financial Instruments Fair Value of Financial Instruments, Policy [Policy Text Block] Inventories and Contracts in Progress Inventory, Policy [Policy Text Block] Property, Plant and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Evaluation of Long-Lived Assets Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Goodwill and Other Intangible Assets Goodwill and Intangible Assets, Policy [Policy Text Block] Investments in Affiliates Equity Method Investments [Policy Text Block] Revenue Recognition Revenue from Contract with Customer [Policy Text Block] Leases Lessee, Leases [Policy Text Block] Pensions and Other Postretirement Benefits Pension and Other Postretirement Plans, Pensions, Policy [Policy Text Block] Self-Insurance Self Insurance Reserve [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Foreign Currency Translation Foreign Currency Transactions and Translations Policy [Policy Text Block] Equity-Based Compensation Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Earnings Per Share Earnings Per Share, Policy [Policy Text Block] Mandatorily Redeemable Noncontrolling Interest Mandatorily Redeemable Noncontrolling Interest [Policy Text Block] Mandatorily Redeemable Noncontrolling Interest [Policy Text Block] Redeemable Noncontrolling Interest Redeemable Noncontrolling Interest [Table Text Block] Comprehensive Income Comprehensive Income, Policy [Policy Text Block] Recently Adopted and Issued Accounting Pronouncemets New Accounting Pronouncements, Policy [Policy Text Block] Unrecognized actuarial (gain) loss Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax Unrecognized prior service cost Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax Gross amount Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax Deferred tax liability (asset) Defined Benefit Plan Accumulated Other Comprehensive Income Tax Tax recorded on the defined benefit plan accumulated other comprehensive income. Net amount Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Contract with Customer, Liability Contract with Customer, Asset and Liability [Table Text Block] Capitalized Contract Cost Capitalized Contract Cost [Table Text Block] Impairment of intangible assets Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill) Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Schedule of Product Information [Table] Schedule of Product Information [Table] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] JacksonvilleFL [Member] JacksonvilleFL [Member] JacksonvilleFL [Member] Product Information [Line Items] Product Information [Line Items] Number of education business categories Number Of Education Business Categories Number of categories that comprise Kaplan's businesses Number of television broadcast stations owned Number Of Television Broadcast Stations Owned Number of television broadcast stations owned by the Company. Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Domain] Debt Instrument, Redemption, Period [Domain] Debt Instrument, Redemption, First Anniversary [Member] Debt Instrument, Redemption, Period One [Member] Debt Instrument, Redemption, Second Anniversary [Member] Debt Instrument, Redemption, Period Two [Member] Debt Instrument, Redemption, Third Anniversary [Member] Debt Instrument, Redemption, Period Three [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] London Interbank Offered Rate (LIBOR) [Member] London Interbank Offered Rate (LIBOR) [Member] Eurodollar [Member] Eurodollar [Member] Federal Funds Effective Swap Rate [Member] Federal Funds Effective Swap Rate [Member] Interest Rate Swap [Member] Interest Rate Swap [Member] Other Indebtedness [Member] Other Indebtedness [Member] Other Indebtedness [Member] Five-Year Revolving Credit Agreement Dated June 29, 2015 [Member] Five Year Revolving Credit Agreement Dated June Twenty-nine Two Thousand Fifteen [Member] Five-year Revolving Credit Agreement dated June 29, 2015 [Member] Five-Year Credit Agreement dated May 30, 2018 [Member] Five-Year Credit Agreement dated May 30, 2018 [Member] Five-Year Credit Agreement dated May 30, 2018 [Member] Multicurrency $100 million portion of revolver [Member] Multicurrency $100 million portion of revolver [Member] Multicurrency $100 million portion of revolver [Member] USD $200 million portion of revolver [Member] USD $200 million portion of revolver [Member] USD $200 million portion of revolver [Member] Interest rate Debt Instrument, Interest Rate, Stated Percentage Maturity year Debt Instrument, Maturity Date Debt instrument, face amount Debt Instrument, Face Amount Redemption of notes outstanding Extinguishment of Debt, Amount Credit facility current borrowing capacity Line of Credit Facility, Current Borrowing Capacity Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Applicable interest rate margin Debt Instrument, Basis Spread on Variable Rate Debt Instrument Price Percentage Of Outstanding Balance Redeemed Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed Debt covenant net leverage ratio, maximum Debt Instrument, Covenant, Net Leverage Ratio, Maximum Maximum net leverage ratio required to be maintained under Credit Agreement. Debt covenant interest coverage ratio, minimum Debt Instrument, Covenant, Interest Coverage Ratio, Minimum Minimum consolidated interest coverage ratio based upon the ratio of consolidated adjusted EBITDA to consolidated interest expense as determined pursuant to the Credit Agreement. Derivative, Notional Amount Derivative, Notional Amount Interest rate swap percentage rate Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate Basis Spread on Variable Rate Derivative, Basis Spread on Variable Rate Average borrowings outstanding Average Outstanding Debt Amount Average borrowings outstanding during the period, both short and long term. Weighted average interest rate of borrowings Debt Instrument, Interest Rate During Period Interest expense Interest Income (Expense), Net Fair value of debt instrument Debt Instrument, Fair Value Disclosure Carrying value of debt instrument Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] AOCI Including Portion Attributable to Noncontrolling Interest [Member] AOCI Including Portion Attributable to Noncontrolling Interest [Member] Unrealized Gain (Loss) on Pensions and Other Postretirement Plans [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward] AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward] Reclassification from accumulated other comprehensive income to retained earnings as a result of adoption of new guidance Reclassification From Accumulated Other Comprehensive Income To Retained Earnings Reclassification from accumulated other comprehensive income to retained earnings Other comprehensive (loss) income before reclassifications Net amount reclassified from accumulated other comprehensive income Reclassification of stranded tax effects to retained earnings as a result of tax reform Antidilutive Restricted Stock Antidilutive Restricted Stock Additional shares excluded in the calculation of diluted EPS as a result of the antidilutive effect of restricted stock using the treasury stock method. Deferred income taxes Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Machinery and Equipment [Member] Machinery and Equipment [Member] Building [Member] Building [Member] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Manufacturing [Member] Manufacturing [Member] Manufacturing business Health Care [Member] Health Care [Member] Revenue Source [Axis] Revenue Source [Axis] Revenue Source [Axis} Revenue Source [Domain] Revenue Source [Domain] [Domain] for Revenue Source [Axis} Advertising Revenue [Member] Advertising Revenue [Member] Advertising Revenue [Member] Retransmission Revenue [Member] Retransmission Revenue [Member] Retransmission Revenue [Member] Other Healthcare Services [Member] Other Healthcare Services [Member] Other Healthcare Services [Member] Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Domain] Timing of Transfer of Good or Service [Domain] Transferred over Time [Member] Transferred over Time [Member] Ownership [Axis] Ownership [Axis] Ownership [Domain] Ownership [Domain] Graham Holdings Company [Member] Graham Holdings Company [Member] Graham Holdings Company [Member] Summary of Significant Accounting Policies [Line Items] Summary of Significant Accounting Policies [Line Items] -- None. No documentation exists for this element. -- Investment maturity length Investment Maturity Length For Classification As Cash And Cash Equivalents Investment maturity length for classification as cash and cash equivalents. Property, Plant and Equipment, Useful Life (in years) Property, Plant and Equipment, Useful Life Amortized Intangible Assets, Useful Life (in years) Number of Performance Obligations Number of Performance Obligations Number of Performance Obligations in standard contract Number of Performance Obligations In Contract With Tuition Cap Number of Performance Obligations In Contract With Tuition Cap Number of Performance Obligations In Contract With Tuition Cap Revenue Recognition, Maximum Period between Recognition of Revenue and Receipt of Payment Revenue Recognition, Maximum Period between Recognition of Revenue and Receipt of Payment Revenue Recognition, Maximum Period between Recognition of Revenue and Receipt of Payment Percentage of Revenue Percentage of Revenue from Contract with Customer, Excluding Assessed Tax Percentage of Revenue Recognized During Period from Contract with Customer, Excluding Assessed Tax Maximum Term of Contract Maximum Term of Contract Maximum Term of Contract Schedule of Quarterly Results of Operations and Comprehensive Income (Loss) Quarterly Financial Information [Table Text Block] Schedule Of Quarterly Impact From Certain Items Schedule Of Quarterly Impact From Certain Items [Table Text Block] Tabular disclosure Quarterly Impact From Certain Items. Cash equivalents and other short-term investments [Member] Cash Equivalents And Other Short Term Investments [Member] -- None. No documentation exists for this element. -- U.S. equities Defined Benefit Plan, Equity Securities, US [Member] International equities Defined Benefit Plan, Equity Securities, Non-US [Member] U.S. stock index fund [Member] Equity Funds, US [Member] An investment that pools funds from many investors to invest in a combination of underlying investments, primarily equity investments, domiciled in United States of America (US). Corporate debt securities [Member] Corporate Debt Securities [Member] Other fixed income securities [Member] Total investments [Member] Total Investments [Member] -- None. No documentation exists for this element. -- Receivables (Payables) for settlement of investments purchased, net [Member] Receivables (Payables) [Member] -- None. No documentation exists for this element. -- Pension plan assets at fair value Summary of Fair Value, Assets and Liabilities Measured on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Benefit obligation at begining of year Defined Benefit Plan, Benefit Obligation Amendments Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment Actuarial (gain) loss Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) Acquisitions Defined Benefit Plan, Benefit Obligation, Business Combination Benefits paid Defined Benefit Plan, Benefit Obligation, Benefits Paid Special termination benefits Defined Benefit Plan, Benefit Obligation, Special and Contractual Termination Benefits Curtailment Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment Benefits paid, net of Medicare subsidy Defined Benefit Plan Benefits Paid Net The amount of payments made for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. Also includes payments made under a postretirement benefit plan, including prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. This item represents a periodic decrease to the plan obligations and a decrease to plan assets. This amount is net of Medicary subsidies. Settlement Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement Benefit obligation at end of year Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Actual return on plan assets Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss) Employer contributions Benefits paid Defined Benefit Plan, Plan Assets, Benefits Paid Benefits paid, net of Medicare subsidy Settlement Defined Benefit Plan, Plan Assets, Payment for Settlement Funded status Defined Benefit Plan, Funded (Unfunded) Status of Plan Income Tax Expense (Benefit), Continuing Operations [Abstract] Income Tax Expense (Benefit), Continuing Operations [Abstract] U.S. Federal, Current Current Federal Tax Expense (Benefit) State and Local, Current Current State and Local Tax Expense (Benefit) Non-U.S., Current Current Foreign Tax Expense (Benefit) Total income tax, Current Current Income Tax Expense (Benefit) U.S. Federal, Deferred Deferred Federal Income Tax Expense (Benefit) State and Local, Deferred Deferred State and Local Income Tax Expense (Benefit) Non-U.S., Deferred Deferred Foreign Income Tax Expense (Benefit) Total income tax, Deferred U.S. Federal, Total Federal Income Tax Expense (Benefit), Continuing Operations State and Local, Total State and Local Income Tax Expense (Benefit), Continuing Operations Non-U.S., Total Foreign Income Tax Expense (Benefit), Continuing Operations Future minimum lease payments for 2019 Operating Leases, Future Minimum Payments Due, Next Twelve Months Future minimum lease payments for 2020 Operating Leases, Future Minimum Payments, Due in Two Years Future minimum lease payments for 2021 Operating Leases, Future Minimum Payments, Due in Three Years Future minimum lease payments for 2022 Operating Leases, Future Minimum Payments, Due in Four Years Future minimum lease payments for 2023 Operating Leases, Future Minimum Payments, Due in Five Years Future minimum lease payments after 2023 Operating Leases, Future Minimum Payments, Due Thereafter Operating leases, future minimum payments due, total Operating Leases, Future Minimum Payments Due Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Education Intersegment Eliminations [Member] Education Intersegment Eliminations [Member] Education Intersegment Eliminations Intersegment Elimination [Member] Intersegment Eliminations [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Revenue Revenue from Contract with Customer, Excluding Assessed Tax U.S. fixed income [Member] Fixed Income Securities, US [Member] Investment that provides a return in the form of fixed periodic payments and eventual return of principal at maturity, domiciled in United States of America (US). Defined Benefit Plan Assets Allocation (Percent) U.S. [Member] UNITED STATES Non U.S. [Member] Non-US [Member] Transferred at Point in Time [Member] Transferred at Point in Time [Member] Contract with Customer, Duration [Axis] Contract with Customer, Duration [Axis] Contract with Customer, Duration [Domain] Contract with Customer, Duration [Domain] Long-term Contract with Customer [Member] Long-term Contract with Customer [Member] Deferred Revenue, Revenue Recognized Deferred Revenue, Revenue Recognized Revenue, Remaining Performance Obligation, Amount Revenue, Remaining Performance Obligation, Amount Revenue Remaining Performance Obligation Percentage of Revenue Expected to be Recognized Over Next 12 Months Revenue Remaining Performance Obligation Percentage of Revenue Expected to be Recognized Over Next 12 Months Revenue Remaining Performance Obligation Percentage of Revenue Expected to be Recognized Over Next 12 Months Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Schedule of Restructuring Costs Restructuring and Related Costs [Table Text Block] Summary of Segment Reporting Information, by Operating Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Summary of Quarterly Operating Results and Comprehensive Income (Loss) (Unaudited) Quarterly Financial Information [Text Block] UNITED KINGDOM UNITED KINGDOM Number of reportable segments Number of Reportable Segments Restructuring costs Accrued restructuring costs Restructuring Reserve Foreign assets Entity Wide Disclosure On Geographic Areas Long-Lived Assets Excluding Goodwill And Other Intangible Assets In Foreign Countries Amount of long-lived assets other than financial instruments, long-term customer relationships of a financial institution, mortgage and other servicing rights, deferred policy acquisition costs, and deferred tax assets, goodwill, and other intangible assets located in foreign countries in total in which the entity holds assets. Pension and Postretirement Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Beginning unrecognized tax benefits Unrecognized Tax Benefits Increases related to current year tax positions Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Increases related to prior year tax positions Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Decrease related to prior year tax positions Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Decreases related to settlement with tax authorities Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities Decreases due to lapse of applicable statute of limitations Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Ending unrecognized tax benefits Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Interest Costs Capitalized Interest Costs Capitalized Property plant and equipment impairment charges Tangible Asset Impairment Charges Leases and Other Commitments Commitments Disclosure [Text Block] Operating Segments [Member] Operating Segments [Member] Subsegments Consolidation Items [Axis] Subsegments Consolidation Items [Axis] Subsegments Consolidation Items [Domain] Subsegments Consolidation Items [Domain] Reportable Subsegments [Member] Reportable Subsegments [Member] Intersubsegment Eliminations [Member] Intersubsegment Eliminations [Member] Income (loss) from operations Interest expense, net Amortization of intangible assets and impairment of goodwill and other long-lived assets Amortization Of Intangible Assets And Impairment Of Goodwill And Other Long-Lived Assets Amortization of intangible assets and impairment of goodwill and other long-lived assets during the period. Pension service cost Capital Expenditures Property, Plant and Equipment, Additions Identifiable Assets Identifiable Assets Identifiable assets by segment are those assets used in the Company's operations in each business segment. Total Assets Capital Stock, Stock Awards And Stock Options Capital Stock, Stock Awards And Stock Options [Text Block] -- None. No documentation exists for this element. -- Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Beginning, Number of Shares Granted, Number of Shares Exercised, Number of Shares Expired or forfeited, Number of Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period End, Number of Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Beginning, Average Option Price (in dollars per share) Granted, Average Option Price (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Exercised, Average Option Price (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Expired or forfeited, Average Option Price (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price End, Average Option Price (in dollars per share) Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Impairment of cost method investment