Statement of Cash Flows [Abstract] Cash Flows from Operating Activities Net Cash Provided by (Used in) Operating Activities [Abstract] Net (Loss) 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 intangible 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. Depreciation and amortization Depreciation, Depletion and Amortization Amortization of lease right-of-use asset Operating Lease Right Of Use Asset Amortization Amount of amortization expense attributable to right-of-use asset from operating lease. Net pension benefit Defined Benefit Plan, Net Periodic Benefit Cost (Credit) 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. Loss (gain) on marketable equity securities and cost method investments, net Unrealized Gain (Loss) on Investments Loss (gain) on disposition of businesses, property, plant and equipment and investments, net Gain (Loss) on Disposition of Assets Provision for doubtful trade receivables Accounts Receivable, Credit Loss Expense (Reversal) Provision for doubtful trade receivables Provision For Doubtful Trade And Other Receivables The amounts of provision for doubtful trade and other receivables. Stock-based compensation expense, net Share-based Payment Arrangement, Noncash Expense Foreign exchange gain Foreign Currency Transaction Gain (Loss), before Tax Write-down of cost method investments Equity Securities without Readily Determinable Fair Value, Impairment Loss, Annual Amount Equity in earnings of affiliates, net of distributions Income (Loss) from Equity Method Investments, Net of Dividends or Distributions (Benefit from) provision for deferred income taxes Deferred Income Tax Expense (Benefit) 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 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 (Used in) 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 Net proceeds from disposition of businesses, property, plant and equipment and investments 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. 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. Proceeds from sales of marketable equity securities Proceeds from Sale and Maturity of Marketable Securities Purchases of marketable equity securities Payments to Acquire Marketable Securities Loan to related party Payments for Advance to Affiliate 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. Net Cash Provided by (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] Common shares repurchased Payments for Repurchase of Common Stock Issuance of borrowings Proceeds from Issuance of Debt Issuance of borrowings Proceeds from Issuance of Long-term Debt Net borrowing under revolving credit facility Proceeds from (Repayments of) Lines of Credit Net proceeds from vehicle floor plan payable Proceeds From (Payments Of) Vehicle Floor Plan Payable Net The net cash inflow or cash outflow from proceeds or repayment of the vehicle floor plan payable. Dividends paid Payments of Ordinary Dividends Issuance of noncontrolling interest Proceeds from Noncontrolling Interests Purchase of noncontrolling interest Payments for Repurchase of Redeemable Noncontrolling Interest Repayments of borrowings Repayments of Long-term Debt Proceeds from exercise of stock options Proceeds from Stock Options Exercised Deferred payments of acquisition Payment for Contingent Consideration Liability, Financing Activities Other Proceeds from (Payments for) Other Financing Activities Net Cash (Used in) Provided by 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 Beginning Cash and Cash Equivalents and Restricted Cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Ending Cash and Cash Equivalents and Restricted Cash Goodwill and Intangible Assets Disclosure [Abstract] Schedule of Goodwill [Table] Schedule of Goodwill [Table] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Education [Member] Education [Member] Education [Member] Television Broadcasting [Member] Television Broadcasting [Member] Television Broadcasting [Member] Manufacturing [Member] Manufacturing [Member] Manufacturing business Healthcare [Member] Graham Healthcare Group [Member] Graham Healthcare Group [Member] SocialCode [Member] SocialCode [Member] SocialCode [Member] Other Businesses [Member] Other Segments [Member] Subsegments [Axis] Subsegments [Axis] Subsegments [Domain] Subsegments [Domain] Kaplan International [Member] Kaplan International [Member] Kaplan International [Member] Higher Education [Member] Higher Education [Member] Higher Education [Member] Test Preparation [Member] Test Preparation [Member] Test Preparation [Member] Professional (U.S.) [Member] Kaplan Professional [Member] Kaplan Professional [Member] Goodwill [Line Items] Goodwill [Line Items] 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 Goodwill Reallocation Goodwill, Transfers Goodwill, Purchase Accounting Adjustments Goodwill, Purchase Accounting Adjustments Acquisitions Goodwill, Acquired During Period Impairment Goodwill, Impairment Loss 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 Statement of Comprehensive Income [Abstract] Other Comprehensive (Loss) Income, Before Tax Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [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 period Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax Pension and other postretirement plans: Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax [Abstract] Amortization of net prior service cost (credit) included in net income Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax Amortization of net actuarial loss (gain) included in net income Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax Total pension and other postretirement plans, before tax Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax Cash flow hedges loss Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax Other Comprehensive (Loss) Income, Before Tax Other Comprehensive Income (Loss), before Tax Income tax benefit related to items of other comprehensive (loss) income Other Comprehensive Income (Loss), Tax Other Comprehensive (Loss) Income, Net of Tax Other Comprehensive Income (Loss), Net of Tax Comprehensive (Loss) Income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive loss attributable to noncontrolling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Total Comprehensive (Loss) Income Attributable to Graham Holdings Company Comprehensive Income (Loss), Net of Tax, Attributable to Parent Income Tax Disclosure [Abstract] Income Taxes [Table] Income Taxes [Table] -- None. No documentation exists for this element. -- Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] CableONE [Member] Cable One [Member] Cable One [Member] Income Taxes [Line Items] Income Taxes [Line Items] Income Taxes [Line Items] Income taxes receivable Income Taxes Receivable, Current Accounts payable and accrued liabilities Accounts Payable and Accrued Liabilities, Current Effective Income Tax Rate Effective Income Tax Rate Reconciliation, Percent Fair Value Measurements [Abstract] Fair Value Measurements [Abstract] Goodwill and Intangible Asset Impairment Goodwill and Intangible Asset Impairment Equity Method Investment Impairment Equity Method Investment, Other than Temporary Impairment Impairment of a cost method investment Gain on cost method investments Equity Securities without Readily Determinable Fair Value, Upward Price Adjustment, Annual Amount Inventory, Net of Allowances, Customer Advances and Progress Billings [Abstract] Schedule of Inventories and Contracts in Progress Schedule of Inventory, Current [Table Text Block] Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] AOCI Including Portion Attributable to Noncontrolling Interest [Member] AOCI Including Portion Attributable to Noncontrolling Interest [Member] Cumulative Foreign Currency Translation Adjustment [Member] Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Unrealized Gain on Pensions and Other Postretirement Plans [Member] Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Cash Flow Hedges [Member] Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [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] As of Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Other comprehensive loss before reclassifications Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Net amount reclassified from accumulated other comprehensive income (loss) Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax As of 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 Inventory, Net of Allowances, Customer Advances and Progress Billings Statement of Financial Position [Abstract] 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 Inventories and contracts in progress Prepaid expenses Prepaid Expense, Current Other current assets Other Assets, Current Total Current Assets Assets, Current Property, Plant and Equipment, Net Property, Plant and Equipment, Net Lease Right-of-Use Assets Operating Lease, Right-of-Use Asset Investments in Affiliates Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Goodwill, Net 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 Income 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] Deferred revenue Deferred Revenue, Current Income taxes payable Accrued Income Taxes, Current Current portion of lease liabilities Operating Lease, Liability, Current Current portion of long-term debt Long-term Debt, Current Maturities Dividends declared Dividends Payable, 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 Income Tax Liabilities, Net Mandatorily Redeemable Noncontrolling Interest Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Share Value, Amount, Noncurrent Lease Liabilities Operating Lease, Liability, Noncurrent Long-Term Debt Long-term Debt, Excluding Current Maturities Total Liabilities Liabilities Redeemable Noncontrolling Interest Redeemable Noncontrolling Interest, Equity, Carrying Amount Preferred Stock 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 tax Cumulative foreign currency translation adjustment Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax Unrealized gain on pensions and other postretirement plans Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax Cash flow hedges Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax Cost of Class B common stock held in treasury Treasury Stock, Value Total Common Stockholders' Equity Stockholders' Equity Attributable to Parent Noncontrolling Interest Stockholders' Equity Attributable to Noncontrolling Interest Total Equity Total Liabilities and Equity Liabilities and Equity Acquisitions And Dispositions [Abstract] Acquisitions and Dispositions Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Capital Contributor [Axis] Capital Contributor [Axis] Capital Contributor [Axis] Capital Contributor [Domain] Capital Contributor [Domain] [Domain] for Capital Contributor [Axis] Graham Holdings Company [Member] Graham Holdings Company [Member] Graham Holdings Company [Member] Group of Senior Managers of GHG [Member] Group of Senior Managers of GHG [Member] Group of Senior Managers of GHG [Member] Ownership [Axis] Ownership [Axis] Ownership [Domain] Ownership [Domain] 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] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Graham Healthcare Group [Member] Professional (U.S.) [Member] Professional (U.S.) [Member] Professional (U.S.) [Member] Transaction [Axis] Transaction [Axis] Transaction [Axis] Transaction Type [Domain] Transaction Type [Domain] Transaction Type [Domain] Kaplan University Transaction [Member] Kaplan University Transaction [Member] Kaplan University Transaction [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] 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) 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) 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, 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, 2027 [Member] After June 30, 2027 [Member] Period of time after June 30, 2027 for which the TOSA term applies 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 Recipient of Consideration [Axis] Recipient of Consideration [Axis] Recipient of Consideration Recipient of Consideration [Domain] Recipient of Consideration [Domain] [Domain] for Recipient of Consideration Purdue University Global [Member] Purdue University Global [Member] Purdue University Global Kaplan [Member] Kaplan [Member] Kaplan [Member] Statistical Measurement [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Minimum [Member] Minimum [Member] GHC One [Member] GHC One [Member] GHC One [Member] Residential Healthcare [Member] Residential Healthcare Group Inc [Member] Residential Healthcare Group Inc [Member] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Celtic Healthcare Allegheny Health Network Joint Venture [Member] CelticHealthcareAlleghenyHealthNetworkJointVenture [Member] A joint venture formed between Celtic Healthcare and Allegheny Health Network 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] Percentage of Contributed Capital Percentage of Contributed Capital Percentage of Contributed Capital Guaranteed Return Guaranteed Return Preferred annual return on portfolio investments guaranteed to the Company 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 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 Renewal Periods Transition and Operations Support Agreement Renewal Periods Transition and Operations Support Agreement Renewal Periods after initial 30 year 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 Percentage of Revenue After Kaplan Efficiency Payment 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 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 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 Gain on sales of businesses Gain (Loss) on Disposition of Business Gain Related to Contingent Consideration Gain Related to Contingent Consideration Contingent consideration gain related to the sale of a business. Number of businesses disposed Number Of Businesses Disposed The number of businesses disposed of by the entity during the period. Percentage of joint venture sold Percentage Of Joint Venture Sold The percentage of a joint venture sold. Ownership percentage of joint venture Equity Method Investment, Ownership Percentage Noncontrolling interest purchased Noncontrolling Interest Purchased Percent of noncontrolling interest purchased during the period. Change in redemption value of manditorily redeemable noncontrolling interest Noncontrolling Interest, Change in Redemption Value Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Percentage of Distributions Available to Common Unit Holders Percentage of Distributions Available to Common Unit Holders Percentage of distributions available to common unit holders Ownership percentage by parent Noncontrolling Interest, Ownership Percentage by Parent Income Taxes Income Tax Disclosure [Text Block] Accounts and Financing Receivable, after Allowance for Credit Loss [Abstract] Accounts Receivable Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Other Nonoperating Income (Expense) [Abstract] Other Non-Operating Income Other Income and Other Expense Disclosure [Text Block] Schedule of assets acquired and liabilities assumed Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Acquisition Pro Forma Financial Information Business Acquisition, Pro Forma Information [Table Text Block] Information related to 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. Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Common Class B [Member] Common Class B [Member] Common Stock [Member] Common Stock [Member] Additional Paid-in Capital [Member] Additional Paid-in Capital [Member] Retained Earnings [Member] Retained Earnings [Member] AOCI Attributable to Parent [Member] AOCI Attributable to Parent [Member] Treasury Stock [Member] Treasury Stock [Member] Noncontrolling Interest [Member] Noncontrolling Interest [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Net (loss) income for the period Issuance of noncontrolling interest Noncontrolling Interest, Increase from Subsidiary Equity Issuance Net loss attributable to noncontrolling interest Noncontrolling Interest in Net Income (Loss) Other Noncontrolling Interests, Nonredeemable Acquisition of noncontrolling interest Noncontrolling Interest, Increase from Business Combination Net income attributable to redeemable noncontrolling interests Net Income (Loss) Attributable to Redeemable Noncontrolling Interest Change in redemption value of redeemable noncontrolling interest Dividends 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 awards and forfeitures Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Amortization of unearned stock compensation and stock option expense APIC, Share-based Payment Arrangement, Increase for Cost Recognition Other comprehensive (loss) income, net of income taxes Purchase of redeemable noncontrolling interest Equity effect of redemption of redeemable noncontrolling interest Equity effect of redemption of redeemable noncontrolling interest Cumulative effect of accounting change Cumulative Effect of New Accounting Principle in Period of Adoption Other Stockholders' Equity, Other Increase (Decrease) in Temporary Equity [Roll Forward] Increase (Decrease) in Temporary Equity [Roll Forward] As of 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. Purchase of redeemable noncontrolling interest Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests Other Temporary Equity, Other Changes As of Segment Reporting [Abstract] 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] Summary of Segment Reporting Information, by Operating Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Revenue from Contract with Customer [Abstract] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] U.S. [Member] UNITED STATES Non-US [Member] Non-US [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] 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] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] 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 Contract with Customer, Asset, Net, Noncurrent Contract with Customer, Asset, Net, Noncurrent Minimum Term of Contract Minimum Term of Contract Minimum Term of Contract 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 Maximum Term of Contract Maximum Term of Contract Maximum Term of Contract Deferred revenue recognized in period related to beginning balance Deferred Revenue, Revenue Recognized Inventories, Contracts in Progress and Vehicle Floor Plan Payable Inventory Disclosure [Text Block] Schedule of Accounts Receivable Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] 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] Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Amortized Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Intangible asset impairment charge Impairment of Intangible Assets, Finite-lived Goodwill and intangible asset impairment charge Asset Impairment Charges Amortization of Intangible Assets Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Amortization of intangible assets Amortization of Intangible Assets Estimated amortization of intangible assets, remainder of 2020 Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year Estimated amortization of intangible assets, 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Two Estimated amortization of intangible assets, 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Three Estimated amortization of intangible assets, 2023 Finite-Lived Intangible Assets, Amortization Expense, Year Four Estimated amortization of intangible assets, 2024 Finite-Lived Intangible Assets, Amortization Expense, Year Five Estimated amortization of intangible assets, after 2024 Finite-Lived Intangible Assets, Amortization Expense, after Year Five Acqusitions and Dispositions [Abstract] Acqusitions and Dispositions [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Maximum [Member] Maximum [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Pinnacle Bank Term Loan [Member] Pinnacle Bank Term Loan [Member] Term loan with Pinnacle Bank Healthcare [Member] Health Care [Member] Clyde's Restaurant Group [Member] Clyde's Restaurant Group [Member] Clyde's Restaurant Group Auto dealerships [Member] Auto dealerships [Member] Auto dealerships Heverald [Member] Heverald [Member] Heverald [Member] CSI Pharmacy Holding Company, LLC [Member] [Member] CSI Pharmacy Holding Company, LLC [Member] [Member] CSI Pharmacy Holding Company, LLC [Member] [Member] Hometown Home Health and Hospice [Member] Hometown Home Health and Hospice [Member] Hometown Home Health and Hospice Genesis [Member] Genesis [Member] Genesis [Member] Red Marker [Member] Red Marker [Member] Red Marker [Member] Joyce/Dayton Corp. [Member] Joyce/Dayton Corp. [Member] Joyce/Dayton Corp. [Member] CSI Pharmarcy [Member] CSI Pharmarcy [Member] CSI Pharmarcy [Member] Automotive [Member] Automotive [Member] Automotive [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Number of Restaurants Number of Restaurants Redeemable Noncontrolling Interest, Equity, Common, Redemption Value Redeemable Noncontrolling Interest, Equity, Common, Redemption Value Percentage Ownership After Change in Noncontrolling Interest Percentage of interest acquired Business Acquisition, Percentage of Voting Interests Acquired Management Fee Management Fee Management fee payable by the Company in connection with management services provided under the management services agreement Advances to Affiliate Advance to Minority Shareholder Advance to Minority Shareholder Interest Rate on Advance to Minority Shareholder Interest Rate on Advance to Minority Shareholder Interest Rate on Advance to Minority Shareholder Percentage of Shares Eligible to be Redeemed Percentage of Shares Eligible to be Redeemed Percentage of share minority shareholders may put to the Company through redeemable noncontrolling interest 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 Derivative, Fixed Interest Rate Derivative, Fixed Interest Rate Acquisition purchase price Business Combination, Consideration Transferred Floor plan payables Vehicle Floor Plan Facility Payable The amount borrowed to finance the purchase of specific vehicle inventories. Number of Stores Number of Stores 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. Purchase Price Net of Cash Business Acquisition, Transaction 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 Loans Payable to Bank Loans Payable to Bank Redeemable noncontrolling interest Redeemable Noncontrolling Interest, Equity, Other, Fair Value Earnings Per Share [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Award Type [Domain] Award Type [Domain] Stock Option Plan [Member] Share-based Payment Arrangement, Option [Member] Restricted Stock Awards [Member] Restricted Stock [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Antidilutive securities, shares Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Dividends declared per common share Common Stock, Dividends, Per Share, Declared Business Segments [Table] Business Segments [Table] Business Segments [Table] Kaplan Corporate and Other [Member] Kaplan Corporate and Other [Member] Kaplan Corporate And Other [Member] Reportable Subsegments [Member] Reportable Subsegments [Member] Subsegments Consolidation Items [Axis] Subsegments Consolidation Items [Axis] Subsegments Consolidation Items [Domain] Subsegments Consolidation Items [Domain] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Operating Segments [Member] Operating Segments [Member] Corporate Office [Member] Corporate, Non-Segment [Member] Business Segments [Line Items] Number of reportable segments Number of Reportable Segments Revenue from Contracts with Customers Revenue from Contract with Customer [Text Block] Debt Disclosure [Abstract] Components of Debt Schedule of Debt [Table Text Block] Acquisitions and Dispositions of Businesses Mergers, Acquisitions and Dispositions Disclosures [Text Block] Other Comprehensive Income (Loss) [Table] Other Comprehensive Income (Loss) [Table] Other Comprehensive Income (Loss) [Table] Foreign Currency Translation Adjustment [Member] Pension and Other Postretirement Plans [Member] Net Prior Service (Credit) Cost [Member] Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member] Net Actuarial Gain [Member] Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [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 Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax Reclassification from AOCI, Current Period, 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), income tax Other Comprehensive Income (Loss), Net of Tax Foreign currency gain, net Impairment of cost method investments Gain on sale of a cost method investment Cost-method Investments, Realized Gain (Loss) Gain on sales of businesses (Loss) gain on sale of an equity affiliate Equity Method Investment, Realized Gain (Loss) on Disposal (Loss) gain on sale of property, plant and equipment Gain (Loss) on Disposition of Property Plant Equipment Other gain (loss), net Other Nonoperating Gains (Losses) Total Other Non-Operating Income Other Nonoperating Income (Expense) Summary of non-operating income Schedule of Other Nonoperating Income (Expense) [Table Text Block] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Amount Revenue, Remaining Performance Obligation, Amount Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Fair Value Disclosures [Abstract] Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2016-02 [Member] Accounting Standards Update 2016-02 [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Total lease liabilities Operating Lease, Liability Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill) Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill) Impairment of goodwill and intangible assets Income Statement [Abstract] Operating Revenues Revenues 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 Total Operating Costs and Expenses Costs and Expenses Income from Operations Operating Income (Loss) Equity in (losses) earnings of affiliates, net Income (Loss) from Equity Method Investments Interest income Investment Income, Interest Interest expense Interest Expense 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, net (Loss) Income Before Income Taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest (Benefit from) Provision for Income Taxes Income Tax Expense (Benefit) Net (Loss) Income Net Loss Attributable to Noncontrolling Interests Net Income (Loss) Attributable to Noncontrolling Interest Net (Loss) Income Attributable to Graham Holdings Company Common Stockholders Net Income (Loss) Attributable to Parent Per Share Information Attributable to Graham Holdings Company Common Stockholders Basic net (loss) income per common share in dollars per share Earnings Per Share, Basic Basic average number of common shares outstanding in shares Weighted Average Number of Shares Outstanding, Basic Diluted net (loss) income per common share in dollars 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. Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Measurement Frequency [Domain] Measurement Frequency [Domain] Fair Value, Recurring [Member] Fair Value, Recurring [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [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] Fair Value, Inputs, Level 3 [Member] Fair Value, Inputs, Level 3 [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 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 Foreign Currency Contracts, Liability, Fair Value Disclosure Foreign Currency Contracts, Liability, Fair Value Disclosure Mandatorily Redeemable Noncontrolling Interest Fair Value Disclosure 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 Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Document Fiscal Year Focus Document Fiscal Year Focus Pro Forma Operating Revenues Business Acquisition, Pro Forma Revenue Pro Forma Net (Loss) Income Business Acquisition, Pro Forma Net Income (Loss) Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] 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] Reclassifications, before tax (Benefit from) Provision for Income Tax Reclassifications, net of tax Interest expense Net of Tax Investments [Abstract] Total Cost Equity Securities, FV-NI, Cost 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 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). Total Fair Value Cover [Abstract] Class A Common Stock [Member] Common Class A [Member] Class B Common Stock [Member] Document Type Document Quarterly Report Document Quarterly Report Document Period End Date Document Transition Report Document Transition Report Entity File Number Entity File Number Entity Registrant Name Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address, Address Line One Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province Entity Address, Postal Zip Code Entity Address, Postal Zip Code City Area Code City Area Code Local Phone Number Local Phone Number Title of 12(b) Security Title of 12(b) Security Trading Symbol Security Exchange Name Security Exchange Name Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Shell Company Entity Shell Company Entity Common Stock, Shares Outstanding Entity Central Index Key Current Fiscal Year End Date Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag (Loss) gain on marketable equity securities, net Less: Net losses (gains) in earnings from marketable equity securities sold and donated Equity Securities, FV-NI, Realized Gain (Loss) Net unrealized (losses) gains in earnings from marketable equity securities still held at the end of the period Equity Securities, FV-NI, Unrealized Gain (Loss) (Loss) Earnings Per Share Earnings Per Share [Text Block] Series of Individually Immaterial Business Acquisitions [Member] Series of Individually Immaterial Business Acquisitions [Member] 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 Lease Right-of-Use Assets Business Combination, Recognized Identifiable Asset Acquired and Liability Assumed, Lease Right-of-Use Asset Amount of lease right of use assets assumed in business combination 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. Floor plan payables 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 Current and noncurrent lease liabilities Business Combination, Recognized Identifiable Asset Acquired and Liabiity Assumed, Current and Noncurrent Lease Liabilities Amount of current and noncurrent lease liabilities assumed in business combination Redeemable noncontrolling interest Noncontrolling interest Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value Aggregate purchase price, net of cash acquired 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. Total Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest Current liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities Other noncurrent assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Cash and cash equivalents Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Other current assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other Redeemable noncontrolling interest 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. Investments in Marketable Equity Securities Marketable Securities [Table Text Block] (Loss) Gain on Marketable Equity Securities Gain (Loss) on Securities [Table Text Block] Business Segments Segment Reporting Disclosure [Text Block] Debt [Table] Debt [Table] Schedule of all debt, including both short term and long term. 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] 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] Commercial note [Member] Commercial note with SunTrust [Member] Commercial Note With SunTrust [Member] Pinnacle Bank Line Of Credit [Member] Pinnacle Bank Line Of Credit [Member] Pinnacle Bank line of credit [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Unsecured notes Unsecured Debt Credit facility Long-term Line of Credit Commercial note Notes Payable to Bank 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 Bad debt expense Schedule of Non-Operating Income (Expense) [Table] Schedule of Non-Operating Income (Expense) [Table] Schedule of Non-Operating Income (Expense) [Table] Gimlet Media [Member] Gimlet Media [Member] Gimlet Media [Member] Schedule of Non-Operating Income (Expense) [Line Items] Schedule of Non-Operating Income (Expense) [Line Items] [Line Items] for Schedule of Non-Operating Income (Expense) [Table] Summary of (Loss) Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Antidilutive Weighted Average Restricted Stock and Options Antidilutive Weighted Average Restricted Stock [Table Text Block] [Table Text Block] for Additional shares excluded in the calculation of diluted EPS as a result of the antidilutive effect of restricted stock using the treasury stock method. Schedule of (Loss) 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. Schedule of (Loss) 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 (loss) 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 (loss) 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 (Loss) 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 (loss) earnings per share Net Income (Loss) Available to Common Stockholders, Diluted Weighted average shares outstanding (shares) Add: Effect of dilutive stock options (shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Denominator for diluted (loss) earnings per share (shares) Weighted Average Number of Shares Outstanding, Diluted Graham Holdings Company Common Stockholders: Income Per Share From Continuing Operations To Common Stockholders [Abstract] Income Per Share From Continuing Operations To Common Shareholders. Basic (loss) income per common share in dollars per share Diluted (loss) income per common share in dollars per share Debt Debt Disclosure [Text Block] Fair Value Measurements Fair Value Disclosures [Text Block] 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] Network Affiliation Agreements [Member] Contract-Based Intangible Assets [Member] Databases and Technology [Member] Database Rights [Member] Non-compete Agreements [Member] Noncompete Agreements [Member] Other [Member] Other Intangible Assets [Member] Useful Life 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] 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] Franchise Agreements [Member] Franchise Rights [Member] 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] Commitments and Contingencies Disclosure [Abstract] Loss Contingencies [Table] Loss Contingencies [Table] 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] UK Pathways [Member] UK Pathways [Member] UK Pathways [Member] Kaplan University [Member] Kaplan University [Member] -- None. No documentation exists for this element. -- Sale of KHE Campuses business [Member] Sale Of KHE Campuses Business [Member] Sale of KHE Campuses business [Member] Applicable Years [Axis] Applicable Years [Axis] Applicable Years [Axis] Applicable Years [Domain] Applicable Years [Domain] [Domain] for Applicable Years [Axis] 2014 to 2018 [Member] 2014 to 2018 [Member] 2014 to 2018 [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 Loss on Guarantor Lease Obligations Loss on Guarantor Lease Obligations The amount of loss recognized on guarantor lease obligations. Amount Paid Entitled To Recover Amount Paid Entitled To Recover The amount paid the Company believes it is entitled to recover. Loss Contingency, Loss in Period Loss Contingency, Loss in Period Number of pending program reviews Number of pending program reviews Number of pending program reviews. Number of finalized program reviews Number Of Finalized Program Reviews Number of finalized program reviews. Number Of Preliminary Program Review Reports received Number Of Preliminary Program Review Reports Received The number of Preliminary Program Review Reports received. Length of program review Length Of Full Review Of Student Files The length of a full review of student files. Length of accreditation term reaffirmed Accreditation Term Reaffirmed The length of the accreditation reaffirmed by the HLC. Organization, Basis of Presentation and Recent Accounting Pronouncements Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Deferred Revenue Deferred Revenue Deferred Revenue, Period Decrease Percentage Deferred Revenue, Period Increase (Decrease) Percentage Deferred Revenue, Period Increase (Decrease) Percentage Goodwill and Other Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Schedule of Investments [Table] Schedule of Investments [Table] Intersection Holdings [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] Residential Healthcare Michigan hospital joint venture [Member] Residential And Michigan Hospital Joint Venture [Member] Residential and a Michigan hospital joint venture [Member] Earnings of two investments [Member] Two investments [Member] Two investments [Member] Framebridge [Member] Framebridge [Member] Framebridge [Member] York Joint Venture [Member] York Joint Venture [Member] York Joint Venture [Member] KIHL [Member] KIHL [Member] KIHL [Member] Schedule of Investments [Line Items] Schedule of Investments [Line Items] Payments to Acquire Marketable Securities Cumulative realized gain (loss) on marketable securities Marketable Securities, Realized Gain (Loss) Gain on marketable equity securities, net Marketable Securities, Realized Gain (Loss), Excluding Other-than-temporary Impairment Loss Equity Method Investment, Ownership Percentage Revenue from Related Parties Revenue from Related Parties Cumulative undistributed income in investments in affiliates Retained Earnings, Undistributed Earnings from Equity Method Investees Income from Equity Method Investments Proceeds from Sale of Equity Method Investments Proceeds from Sale of Equity Method Investments Advances to Affiliate Advances to Affiliate Loan Receivable, Payment Terms 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 Cost method investments Equity Securities without Readily Determinable Fair Value, Amount Retirement Benefits, Description [Abstract] Pension and Postretirement Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Contingencies and Regulatory Matters Commitments and Contingencies Disclosure [Text Block] Accumulated Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Weighted average 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. Weighted average stock options Antidilutive Options Additional shares excluded in the calculation of diluted EPS as a result of the antidilutive effect of options using the treasury stock method. Intersegment Elimination [Member] Intersegment Eliminations [Member] Intersubsegment Eliminations [Member] Intersubsegment Eliminations [Member] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Defined Benefit Pension Plan [Member] Pension Plan [Member] Income (Loss) from Operations Interest Expense, Net Interest Income (Expense), Net Other income, net (Loss) Income Before Income Taxes Amortization of Intangible Assets and Impairment of Goodwill and Intangible Assets Amortization Of Intangible Assets And Impairment Of Goodwill and Intangible Assets Amortization of intangible assets and impairment of goodwill and intangible assets during the period. Amortization Of Intangible Assets and Impairment of Goodwill and Intangible Assets Amortization Of Intangible Assets and Impairment of Long-Lived Assets Amortization of intangible assets and impairment of long-lived assets during the period. Amortization of Intangible Assets Pension Service Cost Defined Benefit Plan, Service Cost Identifiable Assets Identifiable Assets Identifiable assets by segment are those assets used in the Company's operations in each business segment. Summary of Other Comprehensive (Loss) Income 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) Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] 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] Supplemental Executive Retirement Plan (SERP) [Member] Supplemental Employee Retirement Plan [Member] Other Postretirement Benefit Plan, Defined Benefit [Member] Other Postretirement Benefits Plan [Member] Schedule of Net Benefit Costs Schedule of Net Benefit Costs [Table Text Block] Schedule of Allocation of Plan Assets Schedule of Allocation of Plan Assets [Table Text Block] Receivable from contracts with customers, less estimated credit losses Accounts Receivable, after Allowance for Credit Loss, Current Other receivables Other Receivables Accounts receivable, net Estimated credit losses Accounts Receivable, Allowance for Credit Loss Basis of Presentation Consolidation, Subsidiaries or Other Investments, Consolidated Entities, Policy [Policy Text Block] Use of Estimates in the Preparation of the Condensed Consolidated Financial Statements Use of Estimates, Policy [Policy Text Block] Recently Adopted and Issued Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Defined Benefit Pension Plans [Member] Defined Benefit Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Domain] Defined Benefit Plan, Plan Assets, Category [Domain] U.S. equities [Member] Defined Benefit Plan, Equity Securities, US [Member] Private investment fund [Member] Private Equity Funds [Member] 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). 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). International equities [Member] Defined Benefit Plan, Equity Securities, Non-US [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Assets Allocation (Percent) Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage Inventory, Current [Table] Inventory, Current [Table] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] London Interbank Offered Rate (LIBOR) [Member] London Interbank Offered Rate (LIBOR) [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Vehicle Floor Plan Facility [Member] Vehicle Floor Plan Facility [Member] Vehicle Floor Plan Facility [Member] Inventory [Line Items] Inventory [Line Items] Applicable interest rate margin Debt Instrument, Basis Spread on Variable Rate Weighted average interest rate Debt Instrument, Interest Rate During Period Borrowing capacity Vehicle Floor Plan Facility Borrowing Capacity The aggregate borrowing capacity under the vehicle floor plan facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facilities. Vehicle floor plan payable Floor plan assistance Vehicle Floor Plan Facility Assistance The amount of assistance received from the manufacturers recognized as a reduction of operating expenses. 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] Other Postretirement Plans [Member] 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) Curtailment gain Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment Special separation benefit expense Defined Benefit Plan, Cost of Providing Special and Contractual Termination Benefits Net Periodic Cost (Benefit) Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] 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. 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] 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. -- 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] Berkshire Hathaway Common Stock [Member] Berkshire Hathaway Common Stock [Member] Berkshire Hathaway Common Stock [Member] Alphabet and Berkshire Hathaway Common Stock [Member] Alphabet And Berkshire Hathaway Common Stock [Member] Alphabet and Berkshire Hathaway Common Stock [Member] 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. -- Separation Incentive Program [Member] Separation Incentive Program [Member] Separation Incentive Program [Member] Investment Managers [Axis] Investment Managers [Axis] Investment Managers [Axis] Investment Managers [Domain] Investment Managers [Domain] [Domain] for Investment Managers [Axis] Investment Manager 1 [Member] Investment Manager 1 [Member] Investment Manager 1 [Member] Investment Manager 2 [Member] Investment Manager 2 [Member] Investment Manager 2 [Member] Percent of plan assets managed internally by the 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 Other Indebtedness [Member] Other Indebtedness [Member] Other Indebtedness [Member] Interest Rate Swap [Member] Interest Rate Swap [Member] Pinnacle Bank Loan & Security Agreement [Member] Pinnacle Bank Loan & Security Agreement [Member] Pinnacle Bank Loan & Security Agreement [Member] Debt Issuance Costs, Net Line of credit facility outstanding Line of Credit Facility, Interest Rate at Period End Line of Credit Facility, Interest Rate at Period End Interest rate Debt Instrument, Interest Rate, Stated Percentage Commercial note payable Debt Instrument, Term Debt Instrument, Term Monthly installment payments Debt Instrument, Periodic Payment, Principal Derivative, Notional Amount Derivative, Notional Amount Fixed interest rate of derivative Total fixed interest rate of derivative Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate Debt Instrument, Face Amount Debt Instrument, Face 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 Average borrowings outstanding Average Outstanding Debt Amount Average borrowings outstanding during the period, both short and long term. Interest Income (Expense), Net Fair value of debt instrument Debt Instrument, Fair Value Disclosure Carrying value of debt instrument Derivative, Basis Spread on Variable Rate Derivative, Basis Spread on Variable Rate Investments Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Selling, General and Administrative Expenses [Member] Selling, General and Administrative Expenses [Member] Operating Expense [Member] Operating Expense [Member] Accounting Standards Update 2016-01 [Member] Accounting Standards Update 2016-01 [Member] Number of television broadcast stations Number Of Television Broadcast Stations Owned Number of television broadcast stations owned by the Company. Number of Operating Segments Number of Operating Segments Prior Period Reclassification Adjustment Prior Period Reclassification Adjustment