Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization 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. Expected return on assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Award Timing Predetermined Award Timing Predetermined [Flag] Indefinite-lived Intangible Assets [Axis] Indefinite-Lived Intangible Assets [Axis] Entity File Number Entity File Number Capital in Excess of Par Value [Member] Additional Paid-in Capital [Member] Tabular List, Table Tabular List [Table Text Block] Defined benefit plan, target allocation percentage of assets Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Income tax benefit related to items of other comprehensive (loss) income Other Comprehensive Income (Loss), income tax Other Comprehensive Income (Loss), Tax Recently Adopted and Issued Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Mandatory redemption settlement amount Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Share Value, Amount Reportable Segment, Aggregation before Other Operating Segment [Member] Reportable Segment, Aggregation before Other Operating Segment [Member] Secured Overnight Financing Rate (SOFR) [Member] Secured Overnight Financing Rate (SOFR) [Member] Investment Manager 2 [Member] Investment Manager 2 [Member] Investment Manager 2 [Member] Goodwill [Line Items] Goodwill [Line Items] Adjustment to Compensation: Adjustment to Compensation [Axis] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Noncurrent Liabilities Held for Sale Noncurrent Liabilities Held for Sale Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent 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. Revenue from Contracts with Customers Revenue from Contract with Customer [Text Block] 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. Schedule of Indefinite-Lived Intangible Assets [Table] Intangible Asset, Indefinite-Lived [Table] Numerator: Numerator [Abstract] Numerator Adjustment to Compensation, Amount Adjustment to Compensation Amount Minimum percentage of plan assets considered as significant concentrations in pension plans Concentration Risk, Percentage 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. Defined Benefit Pension Plan [Member] Defined Benefit Pension Plans [Member] Pension Plan [Member] Contract costs capitalized during the period Contract Costs Capitalized During the Period Capitalized contract costs associated with new contracts entered into during the period. Stock-based compensation expense, net of forfeitures Share-Based Payment Arrangement, Noncash Expense Stock Options [Member] Stock Option Plan [Member] Share-Based Payment Arrangement, Option [Member] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Add: Dividends paid-common stock outstanding Dividends, Common Stock, Cash Total Common Stockholders’ Equity Equity, Attributable to Parent Impairment of goodwill and asset group held for sale Total impairment charges Impairment of Goodwill and Asset Group Held for Sale Asset Impairment Charges Measurement Frequency [Axis] Measurement Frequency [Axis] Insider Trading Policies and Procedures [Line Items] Honda auto dealership [Member] Honda auto dealership [Member] Honda auto dealership World of Good Brands [Member] World of Good Brands [Member] World of Good Brands Fair Value, Recurring [Member] Fair Value, Recurring [Member] 5.75% Unsecured Notes maturing in 2026 [Member] Five Point Seven Five Percent Unsecured Notes maturing in 2026 [Member] Five Point Seven Five Percent Unsecured Notes maturing in 2026 [Member] Liabilities and Equity Liabilities and Equity [Abstract] Cover [Abstract] Cover [Abstract] Maximum [Member] Maximum [Member] Useful Life Finite-Lived Intangible Asset, Useful Life Net Income Attributable to Noncontrolling Interests Net Income (Loss) Attributable to Noncontrolling Interest Amortized Intangible Assets, Net Net Carrying Amount Finite-Lived Intangible Assets, Net Other assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Assets Amount of other assets acquired at the acquisition date. Restricted Stock [Member] Restricted Stock [Member] Deferred Revenue, Period Increase (Decrease) Percentage Deferred Revenue, Period Increase (Decrease) Percentage Deferred Revenue, Period Increase (Decrease) Percentage Dekko [Member] Dekko [Member] Dekko member Schedule of Earnings Per Share, Basic and Diluted, Including Two Class Method [Line Items] Schedule of Earnings Per Share, Basic and Diluted, Including Two Class Method [Line Items] [Line Items] for Disclosures pertaining to an entity's basic and diluted earnings per share. Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Debt Instrument [Line Items] Debt Instrument [Line Items] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Kaplan, Graham Media Group, WGB, Saatchi Art, Society6, Code3 and Decile [Member] Kaplan, Graham Media Group, WGB, Saatchi Art, Society6, Code3 and Decile [Member] Kaplan, Graham Media Group, WGB, Saatchi Art, Society6, Code3 and Decile Vehicle Floor Plan Facility [Member] Vehicle Floor Plan Facility [Member] Vehicle Floor Plan Facility [Member] Higher Education [Member] Higher Education [Member] Higher Education [Member] Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Total Debt Debt, Long-Term and Short-Term, Combined Amount Other Indebtedness [Member] Other Indebtedness [Member] Other Indebtedness [Member] Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Income Before Income Taxes Income Before Income Taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Entity Shell Company Entity Shell Company Issuance of borrowings Proceeds from Issuance of Debt Clyde's Restaurant Group [Member] Clyde's Restaurant Group [Member] Clyde's Restaurant Group Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Operating Segments [Member] Operating Segments [Member] Comprehensive income attributable to noncontrolling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] Other receivables Other Receivables Number of countries Number of Countries in which Entity Operates Organization, Consolidation and Presentation of Financial Statements [Table] Organization, Consolidation and Presentation of Financial Statements [Table] Organization, Consolidation and Presentation of Financial Statements Current portion of lease liabilities Operating Lease, Liability, Current Cumulative realized net gains on sales of marketable securities Marketable Security, Realized Gain (Loss) Document Fiscal Period Focus Document Fiscal Period Focus Award Timing Method Award Timing Method [Text Block] Award Type [Axis] Award Type [Axis] Adjustments for New Accounting Pronouncements [Axis] Accounting Standards Update [Axis] Foreign Currency Translation Adjustment [Member] Cumulative Foreign Currency Translation Adjustment [Member] Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Acquisition Pro Forma Financial Information Business Combination, Pro Forma Information [Table Text Block] Investment, Name [Domain] Investment, Name [Domain] Trading Symbol Trading Symbol Early Retirement Program Expense [Domain] Early Retirement Program Expense [Domain] -- None. No documentation exists for this element. -- Entity Address, City or Town Entity Address, City or Town Number of investment companies actively managing plan assets Number Of Investment Companies Managing Plan Assets The number of investment companies actively managing plan assets. Effect Of Currency Exchange Rate Change Effect of Exchange Rate on Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Percent allocated to common stockholders Percentage Of Undistributed Earnings Allocated To Common Stockholders Represents the percentage allocation of undistributed earnings to common stockholders. Income Statement Location [Domain] Statement of Income Location, Balance [Domain] Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Acquisition purchase price Business Combination, Consideration Transferred Entity Emerging Growth Company Entity Emerging Growth Company Operating Expense [Member] Operating Expense [Member] Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Unamortized debt issuance costs Debt Issuance Costs, Net Mary Free Bed at Home [Member] Mary Free Bed at Home [Member] Residential and a Michigan hospital joint venture [Member] Indefinite-Lived Intangible Assets Indefinite-Lived Intangible Assets (Excluding Goodwill) Credit loss expense Credit loss expense Accounts Receivable, Credit Loss Expense (Reversal) Deferred revenue Disposal Group, Including Discontinued Operation, Deferred Revenue, Current Investments in Marketable Equity Securities Marketable Securities [Table Text Block] Pension and other postretirement plans: Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax [Abstract] Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable And Accrued Liabilities Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable And Accrued Liabilities [Text Block] The entire disclosure of Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable And Accrued Liabilities Prepaid Pension Cost Assets for Plan Benefits, Defined Benefit Plan Recipient of Consideration [Axis] Recipient of Consideration [Axis] Recipient of Consideration Income taxes payable Accrued Income Taxes, Current Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Effective interest rate Debt Instrument, Interest Rate, Effective Percentage Entity Address, Postal Zip Code Entity Address, Postal Zip Code Restatement Determination Date Restatement Determination Date Provision for Income Taxes Income Tax Expense (Benefit) Applicable interest rate margin Debt Instrument, Basis Spread on Variable Rate Class B Common Stock [Member] Common Class B [Member] Common Class B [Member] Unsecured notes Unsecured Debt 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. Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Subsegments [Axis] Subsegments [Axis] Accounts Receivable Accounts Payable And Accrued Liabilities [Abstract] Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable And Accrued Liabilities [Abstract] -- None. No documentation exists for this element. -- Subsegments Consolidation Items [Domain] Subsegments Consolidation Items [Domain] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Capitalized Contract Cost Capitalized Contract Cost [Table Text Block] Prime Rate [Member] Prime Rate [Member] Vehicle Floor Plan Facility - New Vehicles [Member] Vehicle Floor Plan Facility - New Vehicles [Member] Vehicle Floor Plan Facility - New Vehicles Amortization of lease right-of-use asset Operating Lease, Right-of-Use Asset, Periodic Reduction Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Acquisitions Goodwill, Acquired During Period Income taxes receivable/payable Increase (Decrease) in Income Taxes Networking and Programming Expenses Networking and Programming Expenses Expenses related to network fees paid to affiliates and programming expenses through syndicated TV shows Proceeds from exercise of stock options Proceeds from Stock Options Exercised Schedule of Error Corrections and Prior Period Adjustments Schedule of Error Corrections and Prior Period Adjustments [Table Text Block] Percentage of Distributions Available to Common Unit Holders Percentage of Distributions Available to Common Unit Holders Percentage of distributions available to common unit holders Acquisitions and Dispositions of Businesses Mergers, Acquisitions and Dispositions Disclosures [Text Block] Investments in certain businesses, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired All Trading Arrangements All Trading Arrangements [Member] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Occupancy Expense Occupancy Expense Amount of net occupancy expense that may include items, such as lease expenses, property taxes and property and casualty insurance expense. Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Realm [Member] Realm [Member] Investment in Realm Number of Automotive Dealerships Owned Number of Automotive Dealerships Owned Number of Automotive Dealerships Owned Net Cash Provided by Operating Activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Franchise Agreements [Member] Franchise Rights [Member] Allegheny Health Network Healthcare at Home [Member] Allegheny Health Network Healthcare at Home [Member] A joint venture formed between Celtic Healthcare and Allegheny Health Network Subsequent Event [Member] Subsequent Event [Member] Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] PEO Total Compensation Amount PEO Total Compensation Amount Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Depreciation of property, plant and equipment Depreciation Expense Depreciation Loans Payable to Bank Loans Payable to Bank Estimated amortization of intangible assets, remainder of 2026 Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year Investments in equity affiliates and cost method 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. Distributions to noncontrolling interests Temporary Equity, Distribution to noncontrolling interests Decrease in redeemable noncontrolling interest balance from payment of dividends or other distributions by the non-wholly owned subsidiary or partially owned entity, included in the consolidation of the parent entity, to the noncontrolling interest holders. Equity Components [Axis] Equity Components [Axis] Change in redemption value of redeemable noncontrolling interests Noncontrolling Interest, Change in Redemption Value GBP revolving credit facility borrowings [Member] GBP revolving credit facility borrowings [Member] GBP revolving credit facility borrowings Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Current assets held for sale (includes $28,801 of cash and $6,041 of restricted cash) Current Assets Held for Sale Disposal Group, Including Discontinued Operation, Current Assets 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. Operating Costs and Expenses Operating Costs and Expenses [Abstract] Goods [Member] Product [Member] Number of reportable segments Number of Reportable Segments KIHL [Member] KIHL [Member] KIHL [Member] Dividends paid Payments of Ordinary Dividends Entity Address, State or Province Entity Address, State or Province Principal payments of finance leases Finance Lease, Principal Payments Delayed Draw Term Loan [Member] Delayed Draw Term Loan (DDTL) [Member] Dividends on common stock Dividends, Common Stock Income (loss) from Operations before Amortization of Intangible Assets and Impairment of Goodwill and Asset Group Held for Sale Operating Income before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets Operating Income before Amortization of Intangible Assets and Impairment of Goodwill and Other Long-Lived Assets Total Current Liabilities Liabilities, Current Individual: Individual [Axis] Acquisitions And Dispositions [Abstract] Acquisitions And Dispositions [Abstract] Acquisitions and Dispositions Issuance of noncontrolling interest Proceeds from Noncontrolling Interests Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Subsidiary, Ownership Percentage, Noncontrolling Owner Repayments of borrowings Repayments of Long-Term Debt Entity Interactive Data Current Entity Interactive Data Current Transaction Type [Domain] Transaction Type [Domain] Transaction Type [Domain] Programs to Cease New Enrollments, Number Programs to Cease New Enrollments, Number Programs to Cease New Enrollments, Number Total foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Kaplan Singapore Kaplan Singapore [Member] Kaplan Singapore Ownership [Domain] Ownership [Domain] Net income attributable to nonredeemable noncontrolling interests Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest Contingently Issuable Shares [Member] Contingently Issuable Shares [Member] Contingently Issuable Shares Floor plan assistance Vehicle Floor Plan Facility Assistance The amount of assistance received from the manufacturers recognized as a reduction of operating expenses. Deferred Charges and Other Assets Other Assets, Noncurrent Entity Central Index Key Entity Central Index Key PEO Name PEO Name Purdue University Global [Member] Purdue University Global [Member] Purdue University Global Operating Revenues Revenues Cumulative foreign currency translation adjustment Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Curtailment gain Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Minimum percentage of total assets considered as significant concentrations Concentration Risk, Threshold Percentage For an entity that discloses a concentration risk threshold in relation to a quantitative amount, which serves as the "benchmark", this concept represents the concentration risk threshold percentage related to the "benchmark". GHC Class B Common Stock issued [Member] GHC Class B Common Stock issued [Member] GHC Class B Common Stock issued Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value, Beginning Balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value, Ending Balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plan [Table] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Work-in-process Inventory, Work in Process, Net of Reserves Gross unrealized gains Equity Securities FV-NI, Accumulated Gross Unrealized Gain Amount of unrealized gain on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Advances to Affiliate Advances to Affiliate Contracts in progress Inventory for Long-Term Contracts or Programs, Gross Exercise Price Award Exercise Price Business Combination, Series of Individually Immaterial Business Combinations [Member] Business Combination, Series of Individually Immaterial Business Combinations [Member] Entity Filer Category Entity Filer Category Class of Stock [Domain] Class of Stock [Domain] Kaplan University Transaction [Member] Kaplan University Transaction [Member] Kaplan University Transaction [Member] Programs Still Offered, Number Programs Still Offered, Number Programs Still Offered, Number Subsequent Event Type [Axis] Subsequent Event Type [Axis] Long-Term Debt Total Long-Term Debt Long-Term Debt, Excluding Current Maturities Estimated amortization of intangible assets, 2029 Finite-Lived Intangible Asset, Expected Amortization, Year Three Retirement Benefits, Description [Abstract] Retirement Benefits, Description [Abstract] Cash held for sale Cash and cash equivalents Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax Reclassifications, before tax Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax Gross Carrying Amount Finite-Lived Intangible Assets, Gross Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Entity Address, Address Line One Entity Address, Address Line One AOCI Attributable to Parent [Member] AOCI Attributable to Parent [Member] Redeemable Noncontrolling Interests As of As of Redeemable Noncontrolling Interest, Equity, Carrying Amount Ownership [Axis] Ownership [Axis] Amortization of prior service credit Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Kaplan, Graham Media Group, Joyce, Dekko, Framebridge, Code3, Slate and Corporate [Member] Kaplan, Graham Media Group, Joyce, Dekko, Framebridge, Code3, Slate and Corporate [Member] Kaplan, Graham Media Group, Joyce, Dekko, Framebridge, Code3, Slate and Corporate Foreign currency translation adjustments: Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax, Portion Attributable to Parent [Abstract] 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] Fair Value as of Grant Date Award Grant Date Fair Value Total Cost Equity Securities, FV-NI, Cost Payroll and Fringe Benefits Expense Compensation Expense, Excluding Cost of Good and Service Sold Undistributed earnings Undistributed Earnings, Basic U.S. equities [Member] Defined Benefit Plan, Equity Securities, US [Member] Disposal Group, Held-for-Sale, Not Discontinued Operations [Member] Disposal Group, Held-for-Sale, Not Discontinued Operations [Member] Summary of Other Non-Operating Expense Schedule of Other Nonoperating Income (Expense) [Table Text Block] Add: Effect of dilutive stock options (shares) Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Total Operating Costs and Expenses Costs and Expenses Document Quarterly Report Document Quarterly Report Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Counterparty Name [Domain] Counterparty Name [Domain] Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Schedule of Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities Schedule of Accounts Payable and Accrued Liabilities [Table Text Block] Value of investments Investments Title Trading Arrangement, Individual Title Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Amortization of net actuarial gain included in net income Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax Accounts and Financing Receivable, after Allowance for Credit Loss [Abstract] Accounts and Financing Receivable, after Allowance for Credit Loss [Abstract] Proceeds from bank overdrafts Proceeds from (Repayments of) Bank Overdrafts Non-PEO NEO Non-PEO NEO [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Other [Member] Other [Member] Other Intangible Assets [Member] Net Prior Service Credit [Member] Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member] Award Type [Domain] Award Type [Domain] Noncontrolling Interests Equity, Attributable to Noncontrolling Interest Equity Awards Adjustments Equity Awards Adjustments [Member] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Minimum Term of Contract Minimum Term of Contract Minimum Term of Contract Compensation Amount Outstanding Recovery Compensation Amount Subsegments [Domain] Subsegments [Domain] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Deferred Revenue Recognized in Period Related to Beginning Balance Contract with Customer, Liability, Revenue Recognized Retirement Plan Type [Domain] Retirement Plan Type [Domain] Schedule of Investments [Line Items] Schedule of Investments [Line Items] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward] AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward] Deferred income taxes Business Combination, Recognized Asset Acquired, Deferred Tax Asset Kaplan Corporate and Other [Member] Kaplan Corporate and Other [Member] Kaplan Corporate And Other [Member] Long-term Contract with Customer [Member] Long-Term Contract with Customer [Member] Goodwill, beginning balance Goodwill, ending balance Goodwill, Gross Contingent consideration liabilities [Member] Contingent consideration liabilities [Member] Contingent consideration liabilities USD revolving credit facility borrowings USD revolving credit facility borrowings [Member] USD revolving credit facility borrowings Accumulated other comprehensive income, net of taxes Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Prepaid expenses Disposal Group, Including Discontinued Operation, Prepaid Expenses Amount classified as prepaid expenses 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. Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Minimum [Member] Minimum [Member] Measurement period adjustments Goodwill, Measurement Period Adjustment Company Selected Measure Name Company Selected Measure Name Education [Member] Education [Member] Education [Member] Net income Business Combination, Pro Forma Information, Pro Forma Income (Loss), after Tax Debt Debt Disclosure [Text Block] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Accounts payable Accounts Payable, Current Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Graham Holdings Company Common Stockholders: Income Per Share From Continuing Operations To Common Stockholders [Abstract] Income Per Share From Continuing Operations To Common Shareholders. Other Comprehensive (Loss) Income, Before Tax Other Comprehensive Income (Loss), before tax Other Comprehensive Income (Loss), before Tax 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. Investment Manager 1 [Member] Investment Manager 1 [Member] Investment Manager 1 [Member] Numerator for diluted earnings per share Net Income (Loss) Available to Common Stockholders, Diluted Television Broadcasting [Member] Television Broadcasting [Member] Television Broadcasting [Member] Loss Contingency Borrower Defense Claims Discharge Loan Amount Loss Contingency Borrower Defense Claims Discharge Loan Amount The amount of money applications seek to discharge of loans. Goodwill [Roll Forward] Goodwill [Roll Forward] Contingencies Commitments and Contingencies Disclosure [Text Block] Diluted average number of common shares outstanding (in shares) Denominator for diluted earnings per share (shares) Weighted Average Number of Shares Outstanding, Diluted Cash paid to settle a significant portion of the mandatorily redeemable noncontrolling interest [Member] Cash paid to settle a significant portion of the mandatorily redeemable noncontrolling interest [Member] Cash paid to settle a significant portion of the mandatorily redeemable noncontrolling interest Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities [Line Items] Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities [Line Items] Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities Berkshire Hathaway Common Stock [Member] Berkshire Hathaway Common Stock [Member] Berkshire Hathaway Common Stock [Member] Markel Corporation [Member] Markel Group Inc. [Member] Markel Group Inc. Entity Small Business Entity Small Business Percentage of interest acquired Business Combination, Voting Equity Interest Acquired, Percentage Net income attributable to redeemable noncontrolling interests Net Income (Loss) Attributable to Redeemable Noncontrolling Interest Databases and Technology [Member] Database Rights [Member] CSI [Member] CSI Pharmacy [Member] CSI Pharmacy Document Transition Report Document Transition Report Underlying Securities Award Underlying Securities Amount Other Comprehensive Income (Loss), before Reclassifications, before Tax Other Comprehensive Income (Loss), before Reclassifications, before Tax Equity Component [Domain] Equity Component [Domain] Document Period End Date Document Period End Date Depreciation, amortization and goodwill and asset group held for sale 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. Estimated credit losses Accounts Receivable, Allowance for Credit Loss Class A Common Stock [Member] Common Class A [Member] Common Class A [Member] Deferred payments of acquisition Payment for Contingent Consideration Liability, Financing Activities Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Schedule of Investments [Table] Schedule of Investments [Table] Accretion of value included in net income Fair​ Value, ​Measurement​ With ​Unobservable ​Inputs ​Reconciliations, ​Recurring ​Basis, ​Liability​, Gain (Loss), Accretion Included in Earnings Fair​ Value, ​Measurement​ With ​Unobservable ​Inputs ​Reconciliations, ​Recurring ​Basis, ​Liability​, Gain (Loss), Accretion Included in Earnings Lease liabilities Increase (Decrease) in Operating Lease Liability Total Equity As of As of Equity, Including Portion Attributable to Noncontrolling Interest Foreign currency exchange rate changes Fair​ Value, ​Measurement​ With ​Unobservable ​Inputs ​Reconciliations, ​Recurring ​Basis, ​Liability​, Foreign Currency Translation Gain (Loss) Fair​ Value, ​Measurement​ With ​Unobservable ​Inputs ​Reconciliations, ​Recurring ​Basis, ​Liability​, Foreign Currency Translation Gain (Loss) Document Type Document Type Level 3 Fair Value, Inputs, Level 3 [Member] Income taxes payable Disposal Group, Including Discontinued Operation, Accrued Income Tax Payable, Current Earnings Per Share Earnings Per Share [Text Block] Name Outstanding Recovery, Individual Name Advertising and Marketing Expense Marketing and Advertising Expense Loss Contingencies [Table] Loss Contingencies [Table] Capital in excess of par value Additional Paid in Capital Accounts receivable, net Accounts receivable, net Accounts Receivable, Current Accounts and Other Receivables, Net, Current Product and Service [Axis] Product and Service [Axis] Operating Revenues Revenue from Contract with Customer, Excluding Assessed Tax GHC One and GHC Two [Member] GHC One and GHC Two [Member] GHC One and GHC Two Kaplan Languages Group (KLG) [Member] Kaplan Languages Group (KLG) [Member] Kaplan Languages Group (KLG) Total Current Assets Assets, Current Statistical Measurement [Axis] Statistical Measurement [Axis] Financial Instruments Subject to Mandatory Redemption, Financial Instrument [Domain] Financial Instruments Subject to Mandatory Redemption, Financial Instrument [Domain] 5.625% Unsecured Notes maturing in 2033 [Member] Five Point Six Two Five Percent Unsecured Notes maturing in 2033 [Member] Five Point Six Two Five Percent Unsecured Notes maturing in 2033 [Member] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Disposal Group Name [Axis] Disposal Group Name [Axis] Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Numerator for basic earnings per share Net Income (Loss) Available to Common Stockholders, Basic Contract with Customer, Duration [Domain] Contract with Customer, Duration [Domain] Current Liabilities Liabilities, Current [Abstract] Operating Expenses Operating Expenses Level 1 Fair Value, Inputs, Level 1 [Member] Line of credit facility outstanding Credit facility Long-Term Line of Credit CSI Pharmacy Holding Company, LLC CSI Pharmacy Holding Company, LLC [Member] CSI Pharmacy Holding Company, LLC [Member] (Gain) loss on disposition of property, plant and equipment and investments, net Gain (Loss) on Disposition of Assets Purchase of redeemable noncontrolling interest Equity effect of redemption of redeemable noncontrolling interest Equity effect of redemption of redeemable noncontrolling interest Diluted net income per common share (in USD per share) Diluted earnings per common share (in USD per share) Earnings Per Share, Diluted Number of Schools ED Discharge Loans Number of Schools ED Discharge Loans The number of schools which ED will discharge loans for students. Receivable from contracts with customers, less estimated credit losses Accounts Receivable, after Allowance for Credit Loss, Current Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] 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] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities [Table] Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities [Table] Accounts Receivable, Accounts Payable, Vehicle Floor Plan Payable and Accrued Liabilities Consolidation Items [Domain] Consolidation Items [Domain] 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 Pension liabilities Business Combination, Recognized Liability Assumed, Pension Liabilities Amount of pension liabilities assumed in business combination and recognized at acquisition date. Other current assets Disposal Group, Including Discontinued Operation, Current Assets, Other Amount classified as other 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. Amortized intangible assets, net Disposal Group, Including Discontinued Operation, Intangible Assets Money Market Investments Money Market Funds, at Carrying Value Estimated amortization of intangible assets, 2028 Finite-Lived Intangible Asset, Expected Amortization, Year Two Reclassification to assets held for sale GoodwillReclassifiedToAssetsHeldForSale 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. Accrued compensation and related benefits Employee-related Liabilities, Current Arconic Architectural Products, LLC [Member] Arconic Architectural Products, LLC [Member] Arconic Architectural Products, LLC Credit facility current borrowing capacity Line of Credit Facility, Current Borrowing Capacity Distributions to noncontrolling interests Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Total pension and other postretirement plans, before tax Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax Number of Shares Held in Investment Investment Owned, Balance, Shares Intersegment Elimination [Member] Intersegment Eliminations [Member] Expiration Date Trading Arrangement Expiration Date Potential claims Per ED Loss Contingency Potential Borrower Defense Claims Per ED Number The number of potential borrower defense claims per the Department of Education (ED). Recipient of Consideration [Domain] Recipient of Consideration [Domain] Recipient of Consideration Intersubsegment Eliminations [Member] Intersubsegment Eliminations [Member] Term Loan maturing in 2027 [Member] Term Loan maturing in 2027 [Member] Term Loan maturing in 2027 Common Stockholders’ Equity Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] 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) GHC One [Member] GHC One [Member] GHC One [Member] Property, Plant and Equipment, Net Property, Plant and Equipment, Net Cumulative undistributed income in investments in affiliates Retained Earnings, Undistributed Earnings from Equity Method Investees 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. Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Accounts receivable, net Increase (Decrease) in Accounts Receivable Deferred charges and other assets Disposal Group, Including Discontinued Operation, Noncurrent Assets, Other Amount classified as other noncurrent 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. Entity Current Reporting Status Entity Current Reporting Status Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] 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). Inventory, Net of Allowances, Customer Advances and Progress Billings [Abstract] Inventory, Net of Allowances, Customer Advances and Progress Billings [Abstract] Transaction [Domain] Transaction [Domain] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Executive Category: Executive Category [Axis] Type of Adoption [Domain] Accounting Standards Update [Domain] Other Comprehensive (Loss) Income, Before Tax Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract] 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. Investment Managers [Axis] Investment Managers [Axis] Investment Managers [Axis] Issuance of borrowings Proceeds from Issuance of Long-Term Debt Current Fiscal Year End Date Current Fiscal Year End Date Education Programs [Axis] Education Programs [Axis] Education Programs Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Vehicle floor plan payable Vehicle Floor Plan Facility Payable The amount borrowed to finance the purchase of specific vehicle inventories. Schedule of Accounts Receivable Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Amortization of net prior service credit included in net income Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax Automotive [Member] Automotive [Member] Automotive [Member] 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] Proceeds from sales of marketable equity securities Proceeds from Sale and Maturity of Marketable Securities Marketable equity securities Investments in Marketable Equity Securities Equity Securities, FV-NI, Current Timing of Transfer of Good or Service [Domain] Timing of Transfer of Good or Service [Domain] Shares excluded from earnings per share Antidilutive securities, shares Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Accounts payable, vehicle floor plan payable and accrued liabilities Total Accounts payable and Accrued liabilities Accounts Payable and Accrued Liabilities, Current Current portion of lease liabilities Disposal Group, Including Discontinued Operation, Lease Liabilities, Current Amount classified as current lease liabilities attributable to disposal group held for sale or disposed of, expected to be disposed of. Net Cash Used in Financing Activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Measure: Measure [Axis] Subsegments Consolidation Items [Axis] Subsegments Consolidation Items [Axis] Debt [Table] Debt [Table] Schedule of all debt, including both short term and long term. Issuance of Class B common stock, net of restricted stock award forfeitures Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Net Actuarial Gain [Member] Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member] Cost of services and goods Cost of Goods and Service, Excluding Depreciation, Depletion, and Amortization Disposal Group Classification [Domain] Disposal Group Classification [Domain] Number of businesses acquired Business Combination, Number of Businesses Acquired 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] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Obligations outstanding related to floor plan facilities associated with new vehicles Supplier Finance Program, Obligation Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Entity Tax Identification Number Entity Tax Identification Number Residential Home Health Illinois [Member] Residential Home Health Illinois [Member] Residential Home Health Illinois [Member] Other Healthcare Businesses [Member] Other Healthcare [Member] Other Healthcare [Member] Other Healthcare Businesses Clarus [Member] Clarus [Member] Clarus Goodwill and Other Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Dividends declared Dividends Payable, Current Changes in Carrying Amount of Goodwill Schedule of Goodwill [Table Text Block] Interest expense Interest expense Interest Expense, Nonoperating Trading Arrangement: Trading Arrangement [Axis] Total Shareholder Return Amount Total Shareholder Return Amount Loss Contingencies [Line Items] Loss Contingencies [Line Items] Corporate Office [Member] Segment Reporting, Reconciling Item, Corporate Nonsegment [Member] Deferred Revenue Recognized of Refundable Prepaid Amounts Deferred Revenue Recognized of Refundable Prepaid Amounts Deferred Revenue Recognized of Refundable Prepaid Amounts Security Exchange Name Security Exchange Name Impairment of goodwill and other intangible assets Goodwill and Intangible Asset Impairment Mandatorily redeemable noncontrolling interest Mandatorily redeemable noncontrolling interest, Current Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Share Value, Amount, Current Defined Benefit Plan, Plan Assets, Category [Domain] Defined Benefit Plan, Plan Assets, Category [Domain] Indefinite-lived Intangible Assets, Major Class Name [Domain] Indefinite-Lived Intangible Assets, Major Class Name [Domain] Prepaid expenses Prepaid Expense, Current 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. Increase (Decrease) in Temporary Equity [Roll Forward] Increase (Decrease) in Temporary Equity [Roll Forward] Statement [Line Items] Statement [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Debt extinguishment amount Extinguishment of Debt, Amount Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Cash and cash equivalents Cash and Cash Equivalent Common Stock [Member] Common Stock [Member] Floor plan payables Floor plan payables Business Combination, Recognized Liability Assumed, Floor Plan Payables Amount of floor plan payables assumed in business combination and recognized at acquisition date Net Decrease in Cash and Cash Equivalents and Restricted Cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Loss (gain) on marketable equity securities Unrealized Gain (Loss) on Investments Statistical Measurement [Domain] Statistical Measurement [Domain] Property, plant and equipment Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment Property, plant and equipment, net Disposal Group, Including Discontinued Operation, Property, Plant and Equipment 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 Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Goodwill expected to be deductible for income tax purposes Business Combination, Goodwill, Expected Tax Deductible, Amount Other Non-Operating Expense Other Income and Other Expense Disclosure [Text Block] Equity in earnings (losses) of affiliates, net Income (Loss) from Equity Method Investments Gain on sale of cost method investment Equity Securities without Readily Determinable Fair Value, FV-NI, Realized Gain (Loss) Amount of realized gain (loss) from sale of investment in equity security without readily determinable fair value with change in fair value recognized in net income (FV-NI). Supplier Finance Program [Axis] Supplier Finance Program [Axis] Contract Asset, Current Contract with Customer, Asset, after Allowance for Credit Loss, Current Schedule of assets and liabilities of businesses classified as held for sale Disposal Groups, Including Discontinued Operations [Table Text Block] Interest expense, net Interest Expense, Net Interest Income (Expense), Nonoperating Shares withheld related to net share settlement Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation 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. Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Basic net income per common share (in USD per share) Basic earnings per common share (in USD per share) Earnings Per Share, Basic Accounts payable and accrued liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Mandatorily redeemable noncontrolling interest [Member] Mandatorily redeemable noncontrolling interest [Member] Mandatorily redeemable noncontrolling interest Other Comprehensive (Loss) Income, Net of Tax Other comprehensive (loss) income, net of income taxes Other Comprehensive Income (Loss), Net of Tax Other Comprehensive Income (Loss), Net of Tax Summary of Segment Reporting Information, by Operating Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Revenue, Remaining Performance Obligation, Amount Revenue, Remaining Performance Obligation, Amount Distributions paid to noncontrolling interests Distributions Paid to Noncontrolling Interest Total amount of cash outflow to a noncontrolling interest. Includes, but not limited to, reduction of noncontrolling interest ownership, dividends paid to the noncontrolling interest and other distributions. Healthcare [Member] Graham Healthcare Group [Member] Healthcare Division [Member] Graham Healthcare Group [Member] Indefinite-Lived Intangible Assets [Line Items] Indefinite-Lived Intangible Assets [Line Items] Impairment charge related to the asset group held for sale Disposal Group, Not Discontinued Operation, Loss (Gain) on Write-down Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Current Assets Assets, Current [Abstract] Total Liabilities and Equity Liabilities and Equity Capital contributions Fair Value, Measurement With Unobservable Inputs Reconciliations, Recurring Basis, Liability, Capital Contributions Fair Value, Measurement With Unobservable Inputs Reconciliations, Recurring Basis, Liability, Capital Contributions Pension and Other Postretirement Plans [Member] Unrealized Gain on Pensions and Other Postretirement Plans [Member] Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Guaranteed Return Guaranteed Return Preferred annual return on portfolio investments guaranteed to the Company Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Net income attributable to redeemable noncontrolling interests Temporary Equity, Net Income Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Other Nonoperating Income (Expense) [Abstract] Other Nonoperating Income (Expense) [Abstract] Capital Expenditures Segment, Expenditure, Addition to Long-Lived Assets Restricted cash held for sale Restricted cash Disposal Group Including Discontinued Operation Restricted Cash Amount classified as restricted cash attributable to disposal group held for sale or disposed of. Average borrowings outstanding Average Outstanding Debt Amount Average borrowings outstanding during the period, both short and long term. Concentration Risk Type [Domain] Concentration Risk Type [Domain] Non-operating pension and postretirement benefit income, net Net Periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component Treasury Stock [Member] Treasury Stock, Common [Member] Pay vs Performance Disclosure [Line Items] Accounts payable and accrued liabilities Disposal Group, Including Discontinued Operation, Accounts Payable and Accrued Liabilities, Current Liabilities Liabilities [Abstract] Separation Incentive Program [Member] Separation Incentive Program [Member] Separation Incentive Program [Member] Total Financial Liabilities Financial Liabilities Fair Value Disclosure Number of television broadcast stations Number Of Television Broadcast Stations Owned Number of television broadcast stations owned by the Company. Mandatorily redeemable noncontrolling interest Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Fair Value of Shares Other Liabilities Other Liabilities, Noncurrent Deferred revenue Increase (Decrease) in Deferred Revenue Additional Amount Payable for CSI Minority Shares [Member] Additional Amount Payable for CSI Minority Shares [Member] Additional Amount Payable for CSI Minority Shares Impairment of goodwill Impairment Goodwill impairment charge Goodwill, Impairment Loss Purchase of noncontrolling interest Payments for Repurchase of Redeemable Noncontrolling Interest Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Current portion of long-term debt Less: current portion Long-Term Debt, Current Maturities Company Selected Measure Amount Company Selected Measure Amount Total Comprehensive Income Attributable to Graham Holdings Company Comprehensive Income (Loss), Net of Tax, Attributable to Parent York Joint Venture [Member] York Joint Venture [Member] York Joint Venture [Member] Disposal Group Name [Domain] Disposal Group Name [Domain] Name Measure Name Securities Subject to Mandatory Redemption [Member] Securities Subject to Mandatory Redemption [Member] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Deferred Income Taxes Deferred Income Tax Liabilities, Net Sterling Overnight Interbank Average Rate (SONIA) [Member] Sterling Overnight Interbank Average Rate (SONIA) [Member] Average of the interest rates that banks pay to borrow sterling overnight from other financial institutions and other institutional investors. Residential Hospice Illinois [Member] Residential Hospice Illinois [Member] Residential Hospice Illinois [Member] Summary of Other Comprehensive Income (Loss) Comprehensive Income (Loss) [Table Text Block] Legal Entity [Axis] Legal Entity [Axis] Total Assets Total Assets Assets Estimated amortization of intangible assets, 2027 Finite-Lived Intangible Asset, Expected Amortization, Year One Cash paid for CSI minority shares [Member] Cash Paid for CSI Minority Shares [Member] Cash Paid for CSI Minority Shares Unrealized gain on pensions and other postretirement plans Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax Geographical [Domain] Geographical [Domain] Noncurrent Assets Held for Sale Noncurrent Assets Held for Sale Disposal Group, Including Discontinued Operation, Noncurrent Assets Amount classified as noncurrent 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. Cash Flows from Operating Activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Other Segment Items Segment Reporting, Other Segment Item, Amount Translation adjustments arising during the period Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax Concentration Risk Type [Axis] Concentration Risk Type [Axis] Inventories and Contracts in Progress Inventory Disclosure [Text Block] 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 Acqusitions and Dispositions [Abstract] Acqusitions and Dispositions [Abstract] Acqusitions and Dispositions [Abstract] Private investment fund [Member] Private Equity Funds [Member] Capital Contributor [Domain] Capital Contributor [Domain] [Domain] for Capital Contributor [Axis] 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] Estimated amortization of intangible assets, 2030 Finite-Lived Intangible Asset, Expected Amortization, Year Four Dividends declared per common share Common Stock, Dividends, Per Share, Declared Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Balance of costs to obtain a contract Capitalized Contract Cost, Net Level 2 Fair Value, Inputs, Level 2 [Member] Investments in Affiliates Equity Method Investments Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Business Combination [Domain] Business Combination [Domain] Capital Contributor [Axis] Capital Contributor [Axis] Capital Contributor [Axis] Related Party [Member] Related Party [Member] Purchase of noncontrolling interest Nonredeemable Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests Decrease in nonredeemable noncontrolling interest (for example, but not limited to, redeeming or purchasing the interests of noncontrolling shareholders, issuance of shares (interests) by the non-wholly owned subsidiary to the parent entity for other than cash, and a buyback of shares (interest) by the non-wholly owned subsidiary from the noncontrolling interests). PEO PEO [Member] 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 Interest income Investment Income, Interest Other Businesses and Corporate Office [Member] Corporate Segment and Other Operating Segment [Member] U.S. [Member] UNITED STATES Change in operating assets and liabilities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Retained Earnings [Member] Retained Earnings [Member] Current liabilities held for sale Current Liabilities Held for Sale Disposal Group, Including Discontinued Operation, 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. Beginning Cash and Cash Equivalents and Restricted Cash Ending Cash and Cash Equivalents and Restricted Cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Income Statement [Abstract] Income Statement [Abstract] Purchases of marketable equity securities Payments to Acquire Marketable Securities Payments to Acquire Marketable Securities Total Financial Assets Investments, Fair Value Disclosure Product and Service [Domain] Product and Service [Domain] Acquisition-related costs Business Combination, Transaction Cost, Excluding Separately Recognized Transaction Net Income Net Income Net Income Net income for the period Net of Tax Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Reportable Subsegments [Member] Reportable Subsegments [Member] Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Business Combination [Table] Business Combination [Table] Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Schedule of assets acquired and liabilities assumed Business Combination, Recognized Asset Acquired and Liability Assumed [Table Text Block] City Area Code City Area Code Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Additional Contract Assets Additional Contract Assets [Member] Additional Contract Assets Kaplan, Graham Media Group, Joyce, Society6, Saatchi Art, Code3 and Corporate [Member] Kaplan, Graham Media Group, Joyce, Society6, Saatchi Art, Code3 and Corporate [Member] Kaplan, Graham Media Group, Joyce, Society6, Saatchi Art, Code3 and Corporate Settlements or distributions Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Contract with Customer, Liability Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] Cash Flows from Investing Activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Contract with Customer, Duration [Axis] Contract with Customer, Duration [Axis] Net pension obligations Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Pension Liabilities, Net Amount of net pension liabilities assumed at the acquisition date Recognized actuarial gain Defined Benefit Plan, Amortization of Gain (Loss) Selling, General and Administrative Expenses [Member] Selling, General and Administrative Expenses [Member] Goodwill, Net Goodwill Goodwill, net, beginning balance Goodwill, net, ending balance Goodwill Loss contingency, estimate of possible loss Loss Contingency, Estimate of Possible Loss Non-US [Member] Non-US [Member] Contingent consideration accretion expense Accretion Expense Identifiable Assets Identifiable Assets Identifiable assets by segment are those assets used in the Company's operations in each business segment. Inventory Business Combination, Recognized Asset Acquired, Inventory, Current Organization, Basis of Presentation and Recent Accounting Pronouncements Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Accounts receivable Business Combination, Recognized Asset Acquired, Receivable, Current Accumulated impairment losses, beginning balance Accumulated impairment losses, ending balance Goodwill, Impaired, Accumulated Impairment Loss Other Performance Measure, Amount Other Performance Measure, Amount Credit loss expense and provision for other receivables Credit Loss Expense And Provision For Other Receivables The amounts of credit loss expense and provision for other receivables. Related Party, Type [Domain] Related and Nonrelated Parties [Domain] (Loss) gain on marketable equity securities, net (Loss) gain on marketable equity securities, net Equity Securities, FV-NI, Gain (Loss) Education and Healthcare Divisions [Member] Education and Healthcare Divisions [Member] Education and Healthcare Divisions Other current assets Other Assets, Current Investments [Abstract] Investments [Abstract] Entity [Domain] Entity [Domain] Net Cash Provided by (Used in) Investing Activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Investments in Affiliates Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Schedule of Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Axis] Schedule of Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Axis] Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Lease right-of-use assets Disposal Group, Including Discontinued Operation, Lease Right-of-Use Assets Amount classified as lease right-of-use assets attributable to disposal group held for sale or disposed of. Document Fiscal Year Focus Document Fiscal Year Focus Diplomas Diplomas [Member] Diplomas Lease Right-of-Use Assets Operating Lease, Right-of-Use Asset Other Businesses [Member] Other Operating Segment [Member] International equities [Member] Defined Benefit Plan, Equity Securities, Non-US [Member] Business Segments Segment Reporting Disclosure [Text Block] Schedule of Goodwill [Table] Goodwill [Table] 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] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Amortized Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Schedule of Net Benefit Costs Schedule of Net Benefit Costs [Table Text Block] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Contingent consideration liabilities Business Combination, Contingent Consideration, Liability Accumulated Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Letter of credit sublimit Line of Credit Facility Sublimit, Current Borrowing Capacity Amount of current borrowing capacity under the credit facility sublimit considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility. Amortization of intangible assets Amortization of Intangible Assets Amortization of Intangible Assets Selling, General and Administrative Expense Selling, General and Administrative Expense Restricted cash Restricted Cash and Cash Equivalent, Current Deferred Income Taxes Deferred Income Tax Assets, Net Summary of Changes in Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Percentage of Contributed Capital Percentage of Contributed Capital Percentage of Contributed Capital Arrangement Duration Trading Arrangement Duration Operating losses of acquired companies since acquisition date Business Combination, Acquiree's Earnings (Loss) since Acquisition Date, Actual Segments [Axis] Segments [Axis] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Local Phone Number Local Phone Number Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Contract Asset, Noncurrent Contract with Customer, Asset, after Allowance for Credit Loss, Noncurrent Other Payment for (Proceeds from) Other Investing Activity Other Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Other Item Assets Assets [Abstract] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Debt Instrument [Axis] Debt Instrument [Axis] Pension Plans Retirement Benefits [Text Block] Fair Value Measurements Fair Value Disclosures [Text Block] Business Combination [Line Items] Business Combination [Line Items] Repurchase of Class B Common Stock Treasury Stock, Value, Acquired, Cost Method Deferred Revenue Deferred Revenue Investment, Name [Axis] Investment, Name [Axis] Interest rate Stated interest rate Debt Instrument, Interest Rate, Stated Percentage Lease Liabilities Operating Lease, Liability, Noncurrent Management Services Management Services Expense Amount of expense for management and operating services Accounts Receivable Accounts Receivable, after Allowance for Credit Loss Entity Registrant Name Entity Registrant Name 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). Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Net pension benefit and special separation benefit expense Net Periodic Cost (Benefit) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Accrued Compensation and Related Benefits Deferred Compensation Liability, Classified, Noncurrent Other Comprehensive Income (Loss) [Table] Other Comprehensive Income (Loss) [Table] Other Comprehensive Income (Loss) [Table] Amount borrowed to finance business acquisition Amount borrowed to finance business acquisition Amount borrowed to finance business acquisition 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. Cost method investments Equity Securities without Readily Determinable Fair Value, Amount Number of Operating Segments Number of Operating Segments Components of Debt Schedule of Debt [Table Text Block] Interest cost Defined Benefit Plan, Interest Cost Related Party, Type [Axis] Related and Nonrelated Parties [Axis] 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 Other liabilities Disposal Group, Including Discontinued Operation, Noncurrent Liabilities, Other Amount classified as other 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. Services [Member] Service [Member] Restatement Determination Date: Restatement Determination Date [Axis] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Noncontrolling interest capital contribution Noncontrolling Interest, Increase from Subsidiary Equity Issuance Other Proceeds from (Payment for) Other Financing Activity Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Net amount reclassified from accumulated other comprehensive income (loss) Reclassifications, net of tax Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax VoluntaryRetirementIncentiveProgram [Member] VoluntaryRetirementIncentiveProgram [Member] Voluntary Retirement Incentive Program Name Trading Arrangement, Individual Name Cash flow hedges gain (loss) Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax Alphabet and Berkshire Hathaway Common Stock [Member] Alphabet And Berkshire Hathaway Common Stock [Member] Alphabet and Berkshire Hathaway Common Stock [Member] Purchase of redeemable noncontrolling interest Noncontrolling interest, decrease from redemptions or purchase of interests Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests Unsecured fixed-rate notes, face amount Debt Instrument, Face Amount Kaplan International [Member] Kaplan International [Member] Kaplan International [Member] Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] 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. Denominator: Denominator [Abstract] Denominator Name Awards Close in Time to MNPI Disclosures, Individual Name Cash flow hedges AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax 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 Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Other gain, net Other Nonoperating Gains (Losses) 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. Deferred income taxes Disposal Group, Including Discontinued Operation, Deferred Tax Liabilities Amortization of unearned stock compensation and stock option expense APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Cost of Class B common stock held in treasury Treasury Stock, Value 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). Other Comprehensive Income (Loss) before Reclassifications, Tax Other Comprehensive Income (Loss) before Reclassifications, Tax AOCI Including Portion Attributable to Noncontrolling Interest [Member] AOCI Including Portion Attributable to Noncontrolling Interest [Member] Liability Class [Axis] Liability Class [Axis] Segments [Domain] Segments [Domain] Income Statement Location [Axis] Statement of Income Location, Balance [Axis] Number of language schools Number of Language Schools Number of Language Schools Investments Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Inventories Increase (Decrease) in Inventories Basis of Presentation Consolidation, Subsidiaries or Other Investments, Consolidated Entities, Policy [Policy Text Block] Loan to related party Payments for Advance to Affiliate Payments for Advance to Affiliate Preferred Stock Preferred Stock, Value, Issued Other liabilities Business Combination, Recognized Liability Assumed, Liability All Executive Categories All Executive Categories [Member] Five-Year Credit Agreement Five-Year Credit Agreement Maturing in 2030 [Member] Five-Year Credit Agreement Maturing in 2030 Finished goods Inventory, Finished Goods, Net of Reserves Common stock Common Stock, Value, Issued Equity in (earnings) losses of affiliates, net of distributions Income (Loss) from Equity Method Investments, Net of Dividends or Distributions Floor plan interest expense Floor plan interest expense Interest expense incurred on vehicle floor plan payable outstanding during the period. Commitments and Contingencies (Note 14) Commitments and Contingencies Bachelors Bachelors [Member] Bachelors Equity Method Investment, Diluted Ownership Percentage Equity Method Investment, Diluted Ownership Percentage Equity Method Investment, Diluted Ownership Percentage Amortized intangible assets Business Combination, Recognized Asset Acquired, Identifiable Intangible Asset, Finite-Lived Network Affiliation Agreements [Member] Contract-Based Intangible Assets [Member] Business Combination [Axis] Business Combination [Axis] Comprehensive Income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Other indebtedness Other Long-Term Debt Noncontrolling Interest [Member] Noncontrolling Interest [Member] Group of Senior Managers of GHG [Member] Group of Senior Managers of GHG [Member] Group of Senior Managers of GHG [Member] Supplemental Executive Retirement Plan (SERP) [Member] Supplemental Employee Retirement Plan [Member] Other Comprehensive Income (Loss) [Line Items] Other Comprehensive Income (Loss) [Line Items] [Line Items] for Other Comprehensive Income (Loss) [Table] Equity Method Investment, Ownership Percentage Equity Method Investment, Ownership Percentage Assets, Total [Member] Assets, Total [Member] Graham Holdings Company [Member] Graham Holdings Company [Member] Graham Holdings Company [Member] PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Percentage of total plan assets Defined Benefit Plan Assets Allocation (Percent) Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage Capital Term Loan maturing in 2028[Member] Capital Term Loan maturing in 2028 [Member] Capital Term Loan maturing in 2028 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 Prior Period Reclassification Adjustment Prior Period Reclassification Adjustment Valuation allowance on assets held for sale Valuation allowance on assets held for sale Disposal Group, Including Discontinued Operation, Valuation Allowance Amount of adjustment to a valuation allowance that reduces the carrying value of a disposal group to its fair value. Promissory Note for CSI minority shares due 2026 [Member] Promissory Note for CSI minority shares due 2026 [Member] Promissory Note for CSI minority shares due 2026 Defined Benefit Plan Assets Total [Member] Defined Benefit Plan Assets Total [Member] -- None. No documentation exists for this element. -- Operating Revenues Revenue from Contract with Customer [Abstract] Fair value of debt instrument Debt Instrument, Fair Value Disclosure FCC licenses [Member] Operating and Broadcast Rights [Member] All Individuals All Individuals [Member] Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Purchases of property, plant and equipment Payments to Acquire Property, Plant, and Equipment Transferred at Point in Time [Member] Transferred at Point in Time [Member] Name Forgone Recovery, Individual Name Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] N2K Networks [Member] N2K Networks [Member] N2K Networks Reclassification out of Accumulated Other Comprehensive Income [Member] Reclassification out of Accumulated Other Comprehensive Income [Member] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Supplemental Education [Member] Supplemental Education [Member] Supplemental Education Concentration in single marketable equity security [Member] Concentration in single marketable equity security [Member] Concentration in single marketable equity security Change in capitalized contract cost, other Change in Capitalized Contract Cost, Other Change in capitalized contract cost, other Foreign currency exchange rate changes Goodwill, Foreign Currency Translation, Gain (Loss) Other current investments Other Short-Term Investments Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Schedule of Finite-Lived Intangible Assets [Table] Intangible Asset, Finite-Lived [Table] Supplier Finance Program [Domain] Supplier Finance Program [Domain] Investment Managers [Domain] Investment Managers [Domain] [Domain] for Investment Managers [Axis] Geographical [Axis] Geographical [Axis] Promissory Notes for CSI Minority Shares due 2028 [Member] Promissory Notes for CSI Minority Shares due 2028 [Member] Promissory Notes for CSI Minority Shares due 2028 Transaction Type [Axis] Transaction Type [Axis] Other assets and other liabilities, net Increase (Decrease) in Other Operating Assets and Liabilities, Net Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Manufacturing [Member] Manufacturing [Member] Manufacturing business Operating revenues Business Combination, Pro Forma Information, Pro Forma Revenue Foreign exchange loss Foreign currency loss, net Gain (Loss), Foreign Currency Transaction, before Tax Deferred revenue Deferred Revenue, Current Loan Receivable Fixed Interest Rate Related Party Transaction, Rate Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Title of 12(b) Security Title of 12(b) Security Changes in fair value Fair​ Value, ​Measurement​ With ​Unobservable ​Inputs ​Reconciliations, ​Recurring ​Basis, ​Liability​, Gain (Loss), Changes in Fair Value Fair​ Value, ​Measurement​ With ​Unobservable ​Inputs ​Reconciliations, ​Recurring ​Basis, ​Liability​, Gain (Loss), Changes in Fair Value Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Costs amortized during the period Capitalized Contract Cost, Amortization Per Share Information Attributable to Graham Holdings Company Common Stockholders Earnings Per Share [Abstract] Ownership percentage by parent Subsidiary, Ownership Percentage, Parent Return of investment in equity affiliates Proceeds from Equity Method Investment, Distribution, Return of Capital Real Estate Term Loan maturing in 2028 [Member] Real Estate Term Loan maturing in 2028 [Member] Real Estate Term Loan maturing in 2028 Antidilutive Weighted Average Restricted Stock Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Dispositions Goodwill, Written off Related to Sale of Business Unit 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. Award Timing Disclosures [Line Items] Early Retirement Program Expense [Axis] Early Retirment Program Expense [Axis] -- None. No documentation exists for this element. -- Schedule of Inventories and Contracts in Progress Schedule of Inventory, Current [Table Text Block] Service cost Pension Service Cost Defined Benefit Plan, Service Cost Net (Loss) Gain on Marketable Equity Securities Gain (Loss) on Securities [Table Text Block] Measurement Frequency [Domain] Measurement Frequency [Domain] Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Other comprehensive (loss) income before reclassifications Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Estimated amortization of intangible assets, after 2030 Finite-Lived Intangible Asset, Expected Amortization, after Year Four Amount of amortization for asset, excluding financial asset and goodwill, lacking physical substance with finite life expected to be recognized after fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). Weighted average interest rate Debt Instrument, Interest Rate During Period Net Income Attributable to Graham Holdings Company Common Stockholders Net income attributable to Graham Holdings Company common stockholders Net Income (Loss) Attributable to Parent Remaining GHC One and GHC Two [Member] Remaining GHC One and GHC Two [Member] Remaining GHC One and GHC Two Interest rate swaps Interest Rate Cash Flow Hedge Liability at Fair Value Other accrued liabilities Other Accrued Liabilities, Current Accounts Payable and Accrued Liabilities, Current [Abstract] Accounts Payable and Accrued Liabilities, Current [Abstract] Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Axis] Segment Reporting Information [Line Items] Business Segments [Line Items] Segment Reporting Information [Line Items] Common shares repurchased Payments for Repurchase of Common Stock Adoption Date Trading Arrangement Adoption Date Contract Asset, Total Contract with Customer, Asset, after Allowance for Credit Loss Assets Held For Sale Assets Held For Sale Policy Policy Text Block [Policy Text Block] Disclosure of the accounting policy describing under what circumstances an asset or business is classified as held for sale. Student and Customer Relationships [Member] Customer Relationships [Member] Income from Operations Income from Operations Operating Income (Loss) Retained earnings Retained Earnings (Accumulated Deficit) Percentage of Refundable Amounts Included Within Contract Liabilities Percentage of Refundable Amounts Included Within Contract Liabilities Percentage of Refundable Amounts Included Within Contract Liabilities. Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Transferred over Time [Member] Transferred over Time [Member] Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill) Impairment of Intangible Assets, Indefinite-Lived (Excluding Goodwill) Class of Stock [Axis] Class of Stock [Axis] Cash Flow Hedges [Member] Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Net repayments of 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. Intangible asset impairment charge Impairment of Intangible Assets, Finite-Lived Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Transaction [Axis] Transaction [Axis] Transaction [Axis] Inventories and contracts in progress Inventories and contracts in progress Inventory, Net of Allowances, Customer Advances and Progress Billings Retirement Plan Type [Axis] Retirement Plan Type [Axis] Other expense, net Total Other Non-Operating Expense Other Nonoperating Income (Expense) Statement [Table] Statement [Table] Provision for deferred income taxes Deferred Income Tax Expense (Benefit) Adjustments to reconcile net income to net cash provided by operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Cash Flows from Financing Activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Variable Rate [Domain] Variable Rate [Domain] EBITDAP EBITDAP Earnings before interest, income taxes, depreciation, amortization and pension service cost 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. Cash overdrafts Bank Overdrafts Hoover Treated Wood Products [Member] Hoover Treated Wood Products [Member] Hoover Treated Wood Products [Member] All Adjustments to Compensation All Adjustments to Compensation [Member] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Amendment Flag Amendment Flag Education Programs [Domain] Education Programs [Domain] Education Programs Schedule of Allocation of Plan Assets Schedule of Allocation of Plan Assets [Table Text Block] Termination Date Trading Arrangement Termination Date Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Claims received Loss Contingency Borrower Defense Claims Received Number Number of claims received Raw materials Inventory, Raw Materials, Net of Reserves Lease liabilities Disposal Group, Including Discontinued Operation, Lease Liabilities, Noncurrent Amount classified as noncurrent lease liabilities attributable to disposal group held for sale or disposed of. Indefinite-lived intangible assets Business Combination, Recognized Asset Acquired, Identifiable Intangible Asset, Indefinite-Lived Revenues of acquired companies since acquisition date Business Combination, Acquiree's Revenue since Acquisition Date, Actual Basic average number of common shares outstanding (in shares) Weighted average shares outstanding (shares) Weighted Average Number of Shares Outstanding, Basic Summary of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Segment Reporting [Abstract] Segment Reporting [Abstract] Amortization of Intangible Assets Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Cost of Revenue Cost of Revenue Special separation benefit expense Defined Benefit Plan, Cost of Providing Special and Contractual Termination Benefits Berkshire Hathaway [Member] Berkshire Hathaway [Member] Berkshire Hathaway Debt Disclosure [Abstract] Debt Disclosure [Abstract] Defined Benefit Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Axis] Reclassification from AOCI, Current Period, Tax Provision for Income Tax Reclassification from AOCI, Current Period, Tax Net (payments) borrowings under revolving credit facilities Proceeds from (Repayments of) Lines of Credit Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Cumulative payments for advance to affiliate Cumulative Payments For Advance to Affiliate The cumulative cash outflow from advancing money to an affiliate (an entity that is related but not strictly controlled by the entity). 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. Income taxes receivable Income Taxes Receivable, Current Less: Net gains in earnings from marketable equity securities sold Equity Securities, FV-NI, Realized Gain (Loss) Accounts receivable, net Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net Use of Estimates in the Preparation of the Condensed Consolidated Financial Statements Use of Estimates, Policy [Policy Text Block] Insider Trading Arrangements [Line Items] Foreign Investments [Member] Foreign Investments [Member] Information about the entity's defined pension plan foreign investments. Equity Securities [Member] Equity Securities [Member] Total Liabilities Liabilities Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Trade Names and Trademarks [Member] Trademarks and Trade Names [Member] 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. Consolidation Items [Axis] Consolidation Items [Axis] Variable Rate [Axis] Variable Rate [Axis] Counterparty Name [Axis] Counterparty Name [Axis] Intersection [Member] Intersection [Member] Intersection Holdings,LLC [Member] Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Non-NEOs Non-NEOs [Member] Mandatorily Redeemable Noncontrolling Interest Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Share Value, Amount, Noncurrent