Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Accumulated Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Other Comprehensive Income (Loss) [Table] Other Comprehensive Income (Loss) [Table] Other Comprehensive Income (Loss) [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Foreign Currency Translation Adjustment [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 Prior Service Cost [Member] Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member] Net Actuarial (Gain) Loss [Member] Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member] Curtailment Gains 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. Curtailment And Settlement Included In Distribution [Member] AccumulatedDefinedBenefitPlansAdjustmentCurtailmentAndSettlementIncludedInDistribution [Member] Accumulated other comprehensive (income) loss related to the curtailment and settlement included in distribution to affiliate component of defined benefit plans attributable to the parent. Cash Flow Hedge [Member] Accumulated Net Gain (Loss) from Cash Flow Hedges 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 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 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 Organization, Consolidation and Presentation of Financial Statements [Abstract] Prospective Adoption of New Accounting Pronouncements [Table] Prospective Adoption of New Accounting Pronouncements [Table] Prospective Adoption of New Accounting Pronouncements [Axis] Prospective Adoption of New Accounting Pronouncements [Axis] Accounting Guidance [Domain] Accounting Guidance [Domain] As reported [Member] Previous Accounting Guidance [Member] Adjustment [Member] Adjustments for New Accounting Pronouncement [Member] Upon Adoption [Member] ASU 2017-07 Adoption [Member] [Member] ASU 2017-07 Adoption [Member] [Member] Item Effected [Line Items] Item Effected [Line Items] Income from Operations Operating Income (Loss) Non-operating pension and postretirement benefit income Non-operating pension and postretirement income Non-operating pension and postretirement income as explained in ASU 2017-08. Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest 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] Retirement Benefits, Description [Abstract] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] 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] Geographic Concentration [Member] Geographic Concentration Risk [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. -- Defined Benefit Plan, Asset Categories [Axis] Defined Benefit Plan, Asset Categories [Axis] Plan Asset Categories [Domain] Plan Asset Categories [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] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Berkshire Hathaway Common Stock [Member] Berkshire Hathaway Common Stock [Member] Berkshire Hathaway Common Stock [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] Supplemental Executive Retirement Plan (SERP) [Member] Supplemental Employee Retirement Plan [Member] Other Postretirement Plans [Member] Other Postretirement Benefits Plan [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. -- Voluntary Retirement Incentive Program [Member] Voluntary Retirement Incentive Program [Member] -- None. No documentation exists for this element. -- Separation Incentive Program [Member] Separation Incentive Program [Member] Separation Incentive Program [Member] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Education [Member] Education [Member] Education [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Maximum [Member] Maximum [Member] Minimum [Member] Minimum [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Forney [Member] Forney [Member] Forney [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. Net Periodic Cost (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. 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 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 Defined Benefit Plan, Actual Plan Asset Allocations Number of foreign countries for which the companys pension plan holds investments that exceed 10% of total plan assets Number Of Foreign Countries For Which Companys Pension Plan Holds Investments That Exceed 10 Percent Of Total Plan Assets Number of foreign countries for which the companys pension plan holds investments that exceed 10% of total plan assets Goodwill and Intangible Assets Disclosure [Abstract] Schedule of Goodwill [Table] Schedule of Goodwill [Table] Television Broadcasting [Member] Television Broadcasting [Member] Television Broadcasting [Member] Other Businesses [Member] Other Businesses [Member] Other Businesses [Member] Subsegments [Axis] Subsegments [Axis] Subsegments [Domain] Subsegments [Domain] Higher Education [Member] Higher Education [Member] Higher Education [Member] Test Preparation [Member] Test Preparation [Member] Test Preparation [Member] Kaplan International [Member] Kaplan International [Member] Kaplan International [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 Measurement period adjustments Goodwill, Purchase Accounting Adjustments Acquisitions Goodwill, Acquired During Period Impairment Goodwill, Impairment Loss Dispositions Goodwill, Written off Related to Sale of Business Unit Reclassification to assets held for sale Goodwill Reclassified To Assets Held For Sale Reclassification of the carrying amount of goodwill associated with a reporting unit that is classified as held for sale in the period, not yet disposed. Foreign currency exchange rate changes Goodwill, Foreign Currency Translation Gain (Loss) Goodwill, ending balance Accumulated impairment losses, ending balance Goodwill, net, ending balance New Accounting Pronouncement, Early Adoption [Table] New Accounting Pronouncement, Early Adoption [Table] Adjustments for Change in Accounting Principle [Axis] Adjustments for Change in Accounting Principle [Axis] Adjustments for Change in Accounting Principle [Domain] Adjustments for Change in Accounting Principle [Domain] As previously reported [Member] Adjustment [Member] As Adopted [Member] New Accounting Pronouncement, Early Adoption, Effect [Member] New Accounting Pronouncement, Early Adoption [Axis] New Accounting Pronouncement, Early Adoption [Axis] New Accounting Principles, Early Adoption [Domain] New Accounting Principles, Early Adoption [Domain] New Accounting Pronouncement, Early Adoption [Line Items] New Accounting Pronouncement, Early Adoption [Line Items] Increase in Restricted Cash Increase (Decrease) in Restricted Cash Net Cash Provided by Operating Activities Net Cash Provided by (Used in) Operating Activities 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 Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] 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] Amortized Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] 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 Finite-Lived Intangible Assets, Net 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] 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] Indefinite-Lived Intangible Assets, Net Indefinite-Lived Intangible Assets (Excluding Goodwill) Investments [Abstract] Investments Investment [Text Block] Statement [Table] Statement [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. -- Q3 2015 [Member] Q3 2015 [Member] Q3 2015 [Member] Statement [Line Items] Statement [Line Items] Number of television broadcast stations Number Of Television Broadcast Stations Owned Number of television broadcast stations owned by the Company. Percentage of ownership indicating control for consolidation purposes Percentage Of Ownership Indicating Control For Consolidation Purposes Defines percentage of ownership required in the Company's domestic and foreign subsidiaries for consolidation of assets, liabilities, results of operations and cash flows of the Company. Immaterial Error Correction Amount Immaterial Error Correction Amount Amount of effect on financial statements related to corrections of prior period errors in the current period financial statements when the effect of the prior period error was immaterial to the prior period financial statements and the current period correction is immaterial to the current period financial statements. Impairment of goodwill Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] 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, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [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] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Assets Assets [Abstract] Money market investments Money Market Funds, at Carrying Value Commercial paper Commercial Paper Total Unsecured short-term debt instrument issued by corporations which are highly liquid investments that are readily convertible to know amounts of cash. 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 Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Vocational School Company [Member] Vocational School Company [Member] Vocational School Company [Member] 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] Goodwill and other long-lived asset impairment charge Asset Impairment Charges Loss on write-downs of cost method investments Cost-method Investments, Other than Temporary Impairment Impairment of long-lived assets Impairment of Long-Lived Assets to be Disposed of Impairment of intangible assets Impairment of Intangible Assets, Finite-lived Debt Disclosure [Abstract] 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] 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] Interest Rate Swap [Member] Interest Rate Swap [Member] Other Indebtedness [Member] Other Indebtedness [Member] Other Indebtedness [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] 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, 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] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Debt Instrument [Line Items] Debt Instrument [Line Items] Unamortized debt issuance costs Debt Issuance Costs, Net Interest rate Debt Instrument, Interest Rate, Stated Percentage Maturity year Debt Instrument, Maturity Date Credit facility current borrowing capacity Line of Credit Facility, Current Borrowing Capacity Applicable interest rate margin Debt Instrument, Basis Spread on Variable Rate Percentage of loan to be repaid Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed Debt covenant leverage ratio, maximum Debt Instrument, Covenant, Leverage Ratio, Maximum Maximum 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. Borrowings outstanding Long-term Line of Credit Notional amount of derivative Derivative, Notional Amount Fixed interest rate of derivative Derivative, Fixed Interest Rate Total fixed interest rate Long-term Debt, Percentage Bearing Fixed Interest, Percentage 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 Net interest expense incurred Interest Expense, Debt Fair value of debt instrument Debt Instrument, Fair Value Disclosure Carrying value of debt instrument Unsecured Debt Debt Instrument, Face Amount Debt Instrument, Face Amount Term of debt instrument Debt Instrument, Term Debt Instrument, Maturity year, start Debt Instrument, Maturity Date Range, Start Income Statement [Abstract] Operating Revenues [Abstract] Revenues [Abstract] Education Education revenue Revenues from a range of education and related services worldwide for students, professionals and other organizations. Advertising Advertising Revenue Other Other Revenue, Net Total 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 Expense 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 Equity in (losses) earnings of affiliates, net Income (Loss) from Equity Method Investments Interest income Investment Income, Interest Interest expense Interest Expense Other income (expense), net Other Nonoperating Income (Expense) Income Before Income Taxes Provision for Income Taxes Income Tax Expense (Benefit) Income (loss) Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Income from Discontinued Operations, Net of Tax Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Net Income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net Income Attributable to Noncontrolling Interests Net Income (Loss) Attributable to Noncontrolling Interest Net Income Attributable to Graham Holdings Company Common Stockholders Net Income (Loss) Attributable to Parent Redeemable Preferred Stock Dividends Redeemable Preferred Stock Dividends Net Income Attributable to Graham Holdings Company Common Stockholders Net Income (Loss) Available to Common Stockholders, Basic Income (loss) from continuing operations Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Income from discontinued operations, net of tax Per Share Information Attributable to Graham Holdings Company Common Stockholders Earnings Per Share [Abstract] Basic income per common share in dollars per share Income (Loss) from Continuing Operations, Per Basic Share Basic income per common share from discontinued operations in dollars per share Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share Basic net 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 income per common share in dollars per share Income (Loss) from Continuing Operations, Per Diluted Share Diluted income per common share from discontinued operations in dollars per share Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share Diluted net 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. Segment Reporting [Abstract] Business Segments [Table] Business Segments [Table] Business Segments [Table] Periods from 2011 to Q2 2015 [Member] Periods from 2011 to Q2 2015 [Member] Periods from 2011 to Q2 2015 [Member] 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] Other Businesses [Member] Other Segments [Member] Corporate Office [Member] Corporate, Non-Segment [Member] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Operating Segments [Member] Operating Segments [Member] Business Segments [Line Items] Business Segments [Line Items] [Line Items] for Business Segments [Table] Number of reportable segments Number of Reportable Segments Commitments and Contingencies Disclosure [Abstract] Loss Contingencies [Table] Loss Contingencies [Table] 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] Urquilla-Diaz And Jajdelski Case [Member] Urquilla-Diaz And Jajdelski Cases [Member] United States of America ex rel. Carlos Urquilla-Diaz et al. v. Kaplan University et al. (unsealed March 25, 2008) and United States of America ex rel. Charles Jajdelski v. Kaplan Higher Education Corp. et al. (unsealed January 6, 2009). [Member] Jajdelski Case [Member] Jajdelski Case [Member] -- None. No documentation exists for this element. -- Title IV Participating Institutions Including Broomall PA and Pittsburgh PA and Kaplan University [Member] Title IV Participating Institutions Including Broomall PA and Pittsburgh PA and Kaplan University [Member] Title IV participating institutions including KHE's Broomall, PA and Pittsburgh, PA locations, and Kaplan University [Member] Title IV participating institutions including Broomall PA and Pittsburgh PA [Member] Title I V Participating Institutions Including Broomall P A And Pittsburgh P A [Member] Title IV participating institutions including Broomall, PA and Pittsburgh, PA [Member] Kaplan University [Member] Kaplan University [Member] -- None. No documentation exists for this element. -- Transaction [Axis] Transaction [Axis] Transaction [Axis] Transaction Type [Domain] Transaction Type [Domain] Transaction Type [Domain] Sale of KHE Campuses business [Member] Sale Of KHE Campuses Business [Member] Sale of KHE Campuses business [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [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 Number of unsealed cases filed by former employees under the U.S. Federal False Claims Act Number Of Unsealed Cases Filed By Former Employees Under U S Federal False Claims Act Number of unsealed cases filed by former employees under the U.S. Federal False Claims Act Separate complaints included In Diaz Case 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 allegations not dismissed Number Of Dismissed Allegations Reversed By The US Circuit Court For The Ninth Judicial Circuit Number of dismissed allegations reversed by the U.S. Circuit Court for the Ninth Judicial Circuit. Number of pending program reviews Number of pending program reviews Number of pending program reviews. Number of claims affirmed for dismissal by US Court of Appeal 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. Number of claims revered and remanded by US Court of Appeal Number of Claims Revered And Remanded by US Court of Appeals Number of claims reversed and remanded by the U.S. Court of Appeals for the Eleventh Judicial Court. 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. Document and Entity Information [Abstract] Document and Entity Information [Abstract] Class A Common Stock [Member] Common Class A [Member] Class B Common Stock [Member] Common Class B [Member] Document Type Amendment Flag Document Period End Date Document Fiscal Year Focus Document Fiscal Period Focus Trading Symbol Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Entity Filer Category Entity Common Stock, Shares Outstanding Unsecured notes UK Credit Facility Other indebtedness Other Long-term Debt Total Debt Debt, Long-term and Short-term, Combined Amount Less: current portion Debt, Current Total Long-Term Debt Long-term Debt, Excluding Current Maturities Other Nonoperating Income (Expense) [Abstract] Foreign currency gain (loss), net Foreign Currency Transaction Gain (Loss), before Tax (Loss) gain on sales of businesses Gain (Loss) on Disposition of Business Loss on write-downs of cost method investments Gain on sale of land Gain (Loss) on Disposition of Property Plant Equipment Gain on sales of marketable equity securities (see Note 2) Marketable Securities, Realized Gain (Loss) Gain on the formation of a joint venture Deconsolidation, Gain (Loss), Amount Other, net Other Nonoperating Gains (Losses) Total Other Non-Operating Income (Expense) Impairment write-down of a marketable equity security Marketable Securities, Realized Loss, Other than Temporary Impairments, Amount Loss on cost method investments Cost-method Investments, Realized Gain (Loss) Additional gain on sale of Classified Ventures Equity Method Investment, Realized Gain (Loss) on Disposal Statement of Comprehensive Income [Abstract] Net Income Other Comprehensive Loss, 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 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, before tax Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax Unrealized gains on available-for-sale securities: Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, [Abstract] Unrealized gains for the period, net Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax Reclassification of realized gain 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 Reclassification adjustment for write-down on available-for-sale security included in net income Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI for Write-down of Securities, before Tax Total unrealized gains on available-for-sale securities, before tax Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before 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 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 (gain) loss included in net income Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax Curtaliment gains included in net income Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax Total pension and other postretirement plans, before tax Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax Cash flow hedge (loss) gain Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax Other Comprehensive Income, Before Tax Income tax expense related to items of other comprehensive income Other Comprehensive Income (Loss), 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 Comprehensive Income (Loss), Net of Tax, Attributable to Parent Total cost Available-for-sale Equity Securities, Amortized Cost Basis Gross unrealized gains Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax Gross unrealized losses Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax Total Fair Value Summary of Other Comprehensive (Loss) Income Comprehensive Income (Loss) [Table Text Block] Summary of Changes in Accumulated Other Comprehensive (Loss) Income 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] Business Segments Segment Reporting Disclosure [Text Block] Geographical [Axis] Geographical [Axis] Plan Asset Location [Domain] Geographical [Domain] U.S. [Member] UNITED STATES International [Member] Non-US [Member] Defined Benefit Pension Plans [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Assets Allocation (Percent) New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Deferred Charges and Other Assets [Member] Deferred Charges and Other Assets [Member] Deferred Charges and Other Assets [Member] Long-term Debt [Member] Long-term Debt [Member] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2015-03 [Member] Accounting Standards Update 2015-03 [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Excess tax benefit recognized Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Benefit, Amount Amount of excess tax benefit booked as a discrete item related to the vesting of stock-based compensation under the adoption of ASU 2016-09. Acquisitions And Dispositions [Abstract] Acquisitions and Dispositions Pro Forma Operating Revenues Business Acquisition, Pro Forma Revenue Pro Forma Net Income Business Acquisition, Pro Forma Net Income (Loss) Goodwill and Other Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Acqusitions and Dispositions [Abstract] Acqusitions and Dispositions [Abstract] Acquisitions and Dispositions of Businesses Mergers, Acquisitions and Dispositions Disclosures [Text Block] Statement of Financial Position [Abstract] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] 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 Current assets held for sale ($1,235 of cash) Disposal Group, Including Discontinued Operation, Current Assets, Current Amount classified as current assets attributable to disposal group held for sale or disposed of, expected to be disposed of within one year or the normal operating cycle, if longer. Total Current Assets Assets, Current Property, Plant and Equipment, Net Property, Plant and Equipment, Net Investments in Affiliates Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Goodwill, Net Amortized 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 Noncurrent Assets Held for Sale Disposal Group, Including Discontinued Operation, Long Lived Asset, Current Amount classified as long lived assets attributable to disposal group held for sale or disposed of within one year or an operation cycle, if longer. 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 Current portion of long-term debt Dividends declared Dividends Payable, Current Total Current Liabilities Liabilities, Current Current liabilities held for sale Disposal Group, Including Discontinued Operations, Current Liabilities, Current Amount classified as current liabilities attributable to disposal group held for sale or disposed of, expected to be disposed of within one year or the normal operating cycle, if longer. Income taxes payable Accrued Income Taxes, Current Deferred income taxes Deferred Tax Liabilities, Net, Current Postretirement Benefits Other Than Pensions Liability, Other Postretirement Defined Benefit Plan, Noncurrent Accrued Compensation and Related Benefits Deferred Compensation Liability, Classified, Noncurrent Other Liabilities Other Liabilities, Noncurrent Deferred Income Taxes Deferred Tax Liabilities, Net, Noncurrent Mandatorily Redeemable Noncontrolling Interest Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Share Value, Amount, Noncurrent Long-Term Debt 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 (loss), net of tax 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), Available-for-sale Securities Adjustment, Net of 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 Class B common stock held in treasury Treasury Stock, Value Noncontrolling Interests Stockholders' Equity Attributable to Noncontrolling Interest Total Equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total Liabilities and Equity Liabilities and Equity Noncurrent Liabilities Held for Sale Disposal Group, Including Discontinued Operation, Noncurrent Liabilities, Current Amount classified as noncurrent liabilities attributable to disposal group held for sale or disposed of, expected to be disposed of within one year or the normal operating cycle, if longer. New Accounting Pronouncement, Early Adoption New Accounting Pronouncement, Early Adoption [Table Text Block] Schedule of Prospective Adoption of New Accounting Pronouncements Schedule of Prospective Adoption of New Accounting Pronouncements [Table Text Block] 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] Investments in Marketable Equity Securities Marketable Securities [Table Text Block] 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] Equity Award [Domain] Equity Award [Domain] Stock Option Plan [Member] Employee Stock 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 Other Postretirement Benefit Plan, Defined Benefit [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] Summary of non-operating income Schedule of Other Nonoperating Income (Expense) [Table Text Block] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Ownership [Axis] Ownership [Axis] Ownership [Domain] Ownership [Domain] Hometown Home Health and Hospice [Member] Hometown Home Health and Hospice [Member] Hometown Home Health and Hospice Hoover Treated Wood Products [Member] Hoover Treated Wood Products [Member] Hoover Treated Wood Products [Member] Genesis [Member] Genesis [Member] Genesis [Member] Red Marker [Member] Red Marker [Member] Red Marker [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] Residential Healthcare Group Inc [Member] Residential Healthcare Group Inc [Member] Residential Healthcare Group Inc [Member] Residential Hospice Illinois [Member] Residential Hospice Illinois [Member] Residential Hospice Illinois [Member] Residential Home Health Illinois [Member] Residential Home Health Illinois [Member] Residential Home Health Illinois [Member] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Group Dekko [Member] Group Dekko [Member] Group Dekko [Member] SmartPros [Member] SmartPros [Member] SmartPros [Member] 2016 Acquisitions [Member] Current Year Acquisitions [Member] Current year acquisitions [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Number of businesses acquired Number of Businesses Acquired Acqusition purchase price Business Combination, Consideration Transferred 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. Percentage of interest acquired Business Acquisition, Percentage of Voting Interests Acquired 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. 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 income of acquired companies since acquisition date Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual Adjustment to goodwill Number of television stations included in agreement to acquire Number Of Television Stations Included In Agreement To Acquire The number of television stations included in agreement to acquire. Number of Business Lines Number of Business Lines The number of business lines. Purchase Price Net of Cash Payments to Acquire Businesses, Net of Cash Acquired Components of Debt Schedule of Debt [Table Text Block] 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. 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 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 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 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 income per common share in dollars per share Diluted income per common share in dollars per share Kaplan [Member] Kaplan [Member] Kaplan [Member] Amortization of Intangible Assets Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Estimated amortization of intangible assets, remainder of 2017 Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year Estimated amortization of intangible assets, 2018 Finite-Lived Intangible Assets, Amortization Expense, Year Two Estimated amortization of intangible assets, 2019 Finite-Lived Intangible Assets, Amortization Expense, Year Three Estimated amortization of intangible assets, 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Four Estimated amortization of intangible assets, 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Five Estimated amortization of intangible assets, after 2021 Finite-Lived Intangible Assets, Amortization Expense, after Year Five Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] KHE Campuses [Member] KHE Campuses [Member] KHE Campuses [Member] Kaplan China [Member] Kaplan China [Member] Kaplan China [Member] Celtic Healthcare Inc [Member] Celtic Healthcare Inc [Member] -- None. No documentation exists for this element. -- Residential Healthcare [Member] Graham Healthcare Group [Member] Graham Healthcare Group [Member] Graham Healthcare Group [Member] Residential Healthcare Michigan hospital joint venture [Member] Residential And Michigan Hospital Joint Venture [Member] Residential and a Michigan hospital joint venture [Member] 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 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 Redemption value of redeemable noncontrolling interest Redeemable Noncontrolling Interest, Equity, Common, Redemption Value Noncontrolling interest exchanged Noncontrolling Interest Exchanged The percentage of redeemable noncontrolling interest exchanged. Ownership percentage of manditorily redeemable noncontrolling interest by noncontrolling owners Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Ownership oercentage by parent Noncontrolling Interest, Ownership Percentage by Parent Number of nationally accredited ground campuses sold Number Of Nationally Accredited Ground Campuses Sold The number of nationally accredited ground campuses sold. Maximum letter of credit or other credit support Guarantor Obligations, Maximum Exposure, Undiscounted Term for letter of credit Length Of Guarantee Length of time for letter of credit or other credit support, if issued. Impairment of long-lived assets Impairment Of Long Lived Assets The aggregate amount of write-downs recognized during the period for long-lived assets. Unfavorable out of period expense adjustment Number of businesses disposed Number Of Businesses Disposed The number of businesses disposed of by the entity during the period. Number of nationally accredited ground campuses Number Of Nationally Accredited Ground Campuses To Be Sold The number of nationally accredited ground campuses to be sold. Intersegment Elimination [Member] Intersegment Eliminations [Member] Cable [Member] Cable [Member] Cable [Member] Newspaper Publishing [Member] Newspaper Publishing [Member] Newspaper Publishing [Member] Corporate Office [Member] Corporate Office [Member] Corporate Office [Member] Intersubsegment Eliminations [Member] Intersubsegment Eliminations [Member] Operating Revenues Income (Loss) from Operations Equity in earnings (losses) of affiliates, net Interest Expense, Net Interest Income (Expense), Net Income Before Income Taxes Amortization of Intangible 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 Amortization of intangible assets and impairment of goodwill and other long-lived assets during the period. Impairment of Goodwill and Other Long-lived Assets Impairment Of Goodwill And Other Long-Lived Assets Total loss recognized during the period from the impairment of goodwill, intangible assets and other long-lived assets. Net Pension (Credit) Expense Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Identifiable Assets Identifiable Assets Identifiable assets by segment are those assets used in the Company's operations in each business segment. Investments in Marketable Equity Securities Assets Held for Sale Disposal Group, Including Discontinued Operation, Assets 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 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. Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] Unrealized Gain on Available-for-Sale Securities [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 income (expense), net Reclassifications, before tax Provision for Income Tax Reclassifications, net of tax Interest expense Net of Tax 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] Pension and Postretirement Plans Pension and Other Postretirement Benefits Disclosure [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 Investments [Table] Schedule of Investments [Table] Markel Corporation [Member] MarkelCorporation [Member] Markel Corporation [Member] Intersection Holdings [Member] Intersection [Member] Intersection Holdings,LLC [Member] York Joint Venture [Member] York Joint Venture [Member] York Joint Venture [Member] Celtic Healthcare [Member] York University [Member] York University [Member] York University [Member] Celtic and Residential [Member] Celtic And Residential [Member] Celtic and Residential [Member] Schedule of Investments [Line Items] Schedule of Investments [Line Items] Commercial paper and money market investments Commercial Paper And Money Market Investments Unsecured short-term debt instrument issued by corporations which are highly liquid investments that are readily convertible to know amounts of cash and interest-bearing accounts that typically pay a higher interest rate and are FDIC insured. Number of shares held in investment Number Of Shares Held In Investment The number of shares held in an investment. Marketable equity securities purchased Available For Sale Securities Equity Acquired Equity securities classified as available-for-sale securities acquired. Cash paid for new marketable equity securities Payments to Acquire Available-for-sale Securities, Equity Proceeds from sales of marketable equity securities Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds Gain on sales of marketable equity securities Marketable Securities, Realized Gain (Loss), Excluding Other than Temporary Impairments Equity Method Investment, Percentage Acquired Subsidiary or Equity Method Investee, Cumulative Percentage Ownership after All Transactions Equity Method Investment, Ownership Percentage Revenue from Related Parties Revenue from Related Parties Loan commitment to affiliate Other Commitment 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 Proceeds from Q1 sales of marketable securities settled in April 2016 Proceeds From Sales Of Marketable Securities Settled Proceeds from sales of marketable securities settled in subsequent period. Impairment write-down on a marketable equity security Statement of Cash Flows [Abstract] Cash Flows from Operating Activities Net Cash Provided by (Used in) Operating Activities [Abstract] 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. Depreciation and amortization Depreciation, Depletion and Amortization Net pension benefit Net Periodic Benefit For Defined Benefit Pension Plans Excluding Early Retirement Program, Special Separation Benefit Expense And Settlement Including Spinoff Curtailment 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. This element includes the curtailment related to the spin-off of a business. Early retirement program expense Stock-based compensation expense, net Share-based Compensation Loss (gain) on disposition of businesses, property, plant and equipment, investments and other assets, net Gain (Loss) on Disposition of Assets Foreign exchange (gain) loss Write-down of cost method investments Net gain 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 disposition 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 equity affiliate Equity in (earnings) losses of affiliates, net of distributions Income (Loss) from Equity Method Investments, Net of Dividends or Distributions Provision (benefit) for deferred income taxes Deferred Income Tax Expense Benefit Including Discontinued Operations The component of income tax expense for the period representing the increase (decrease) in the entity's deferred tax assets and liabilities. Net loss on sale of property, plant and equipment Net loss (gain) on sale or write-down 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 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 Cash Flows from Investing Activities Net Cash Provided by (Used in) Investing Activities [Abstract] Investments in certain businesses, net of cash acquired 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. 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. Purchases of property, plant and equipment Payments to Acquire Property, Plant, and Equipment Disbursement of loan to affiliate Payments to Fund Long-term Loans to Related Parties Return of investment in equity affiliate Proceeds from Equity Method Investment, Distribution, Return of Capital Net proceeds from disposition of businesses, property, plant and equipment, investments 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. Proceeds from sales of marketable equity securities Proceeds from Sale of Available-for-sale Securities, Equity Purchases of marketable equity securities Investments in commercial paper Investments In Commercial Paper Cash outflow from investments in commercial paper. Proceeds from maturities of commercial paper Proceeds From Maturities Of Commercial Paper Cash inflow from maturities of commercial paper. 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] Common shares repurchased Payments for Repurchase of Common Stock Dividends paid Payments of Ordinary Dividends Repayments of borrowings Proceeds from (Repayments of) Debt Repayments of borrowings Repayments of Long-term Debt Deferred payments of acquisition and noncontrolling interest Deferred Payments Of Acquisition And Noncontrolling Interest Deferred payments made related to acquisitions and noncontrolling interest. Issuance of borrowings Proceeds from Issuance of Long-term Debt Purchase of noncontrolling interest Payments for Repurchase of Redeemable Noncontrolling Interest Proceeds from exercise of stock options Proceeds from Stock Options Exercised Payments of financing costs Payments of Financing Costs Other Proceeds from (Payments for) Other Financing Activities 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 Beginning Cash and Cash Equivalents and Restricted Cash Ending Cash and Cash Equivalents and Restricted Cash Debt Debt Disclosure [Text Block] 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 Benefit Net Periodic Cost (Benefit) Curtailment gain 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] Cumulative Foreign Currency Translation Adjustment [Member] Unrealized Gain 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] Accumulated Other Comprehensive Income, beginning balance Other comprehensive (loss) income before reclassifications Net amount reclassified from accumulated other comprehensive income Accumulated Other Comprehensive Income, ending balance Acquisitions and Dispositions of Businesses [Abstract] Acquisitions and Dispositions of Businesses [Abstract] Other Intangible Assets [Member] 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 Other current assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other 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 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 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 Weighted Average Life (in years) Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Investments In Affiliates Subsidiaries Associates And Joint Ventures Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Investments In Affiliates Subsidiaries Associates And Joint Ventures Total investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable from a party that is affiliated with the reporting entity by means of direct or indirect ownership, acquired at the acquisition date. Schedule of Non-Operating Income (Expense) [Table] Schedule of Non-Operating Income (Expense) [Table] Schedule of Non-Operating Income (Expense) [Table] Prior Period Adjustment [Member] Restatement Adjustment [Member] Colloquy [Member] Colloquy [Member] Colloquy [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] Favorable out of period adjustment 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. 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. Other Non-Operating Income Other Income and Other Expense Disclosure [Text Block] Earnings Per Share Earnings Per Share [Text Block] Contingencies Commitments and Contingencies Disclosure [Text Block] Organization, Basis of Presentation and Recent Accounting Pronouncements Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block]