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Note 2 - Summary of Significant Accounting Policies (Details Textual) (USD $) | 11 Months Ended | 12 Months Ended | 0 Months Ended | 1 Months Ended | 0 Months Ended | 10 Months Ended
--- | --- | --- | --- | --- | --- | ---
Sep. 03, 2014 | Sep. 30, 2014 | Sep. 30, 2013 | Sep. 30, 2012 | Sep. 13, 2013 | Sep. 30, 2013 | Dec. 04, 2012 | Sep. 30, 2013
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Finite-Lived Intangible Assets, Amortization Expense, Year Two |  | $ 4,895,000 us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo |  |  |  |  |  |
Finite-Lived Intangible Assets, Amortization Expense, Year Three |  | 4,895,000 us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree |  |  |  |  |  |
Weighted Average Number of Shares Outstanding, Basic and Diluted | 1,380,746 us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted | 1,380,746 us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted | 1,380,746 us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted | 1,380,746 us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted |  |  |  |
Goodwill |  | 13,400,000 us-gaap_Goodwill | 13,400,000 us-gaap_Goodwill |  |  | 13,400,000 us-gaap_Goodwill |  | 13,400,000 us-gaap_Goodwill
Liability for Uncertain Tax Positions, Current |  |  | 0 us-gaap_LiabilityForUncertainTaxPositionsCurrent | 0 us-gaap_LiabilityForUncertainTaxPositionsCurrent |  | 0 us-gaap_LiabilityForUncertainTaxPositionsCurrent |  | 0 us-gaap_LiabilityForUncertainTaxPositionsCurrent
Available-for-sale Securities |  | 173,676,000 us-gaap_AvailableForSaleSecurities | 136,994,000 us-gaap_AvailableForSaleSecurities |  |  | 136,994,000 us-gaap_AvailableForSaleSecurities |  | 136,994,000 us-gaap_AvailableForSaleSecurities
Available-for-sale Securities, Gross Unrealized Gain (Loss) |  | 125,700,000 us-gaap_AvailableforsaleSecuritiesGrossUnrealizedGainLoss1 | 89,018,000 us-gaap_AvailableforsaleSecuritiesGrossUnrealizedGainLoss1 |  |  |  |  |
Deferred Tax Liabilities, Investments |  | 48,896,000 us-gaap_DeferredTaxLiabilitiesInvestments | 34,610,000 us-gaap_DeferredTaxLiabilitiesInvestments | 20,898,000 us-gaap_DeferredTaxLiabilitiesInvestments |  | 34,610,000 us-gaap_DeferredTaxLiabilitiesInvestments |  | 34,610,000 us-gaap_DeferredTaxLiabilitiesInvestments
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net |  |  | 1,719,000 us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNet | 2,855,000 us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNet |  |  |  |
Amortization of Intangible Assets |  | 4,866,000 us-gaap_AmortizationOfIntangibleAssets | 1,865,000 us-gaap_AmortizationOfIntangibleAssets | 0 us-gaap_AmortizationOfIntangibleAssets |  |  |  |
Business Combination, Pro Forma Information, Disclosure Impracticable, Interest Expense |  |  | 133,000 djco_BusinessCombinationProFormaInformationDisclosureImpracticableInterestExpense | 221,000 djco_BusinessCombinationProFormaInformationDisclosureImpracticableInterestExpense |  |  |  |
Business Combination, Pro Forma Information Disclosure Impracticable Intangible Amortization |  |  | 3,370,000 djco_BusinessCombinationProFormaInformationDisclosureImpracticableIntangibleAmortization | 5,235,000 djco_BusinessCombinationProFormaInformationDisclosureImpracticableIntangibleAmortization |  |  |  |
Finite-Lived Intangible Assets, Net |  | 17,744,000 us-gaap_FiniteLivedIntangibleAssetsNet | 22,610,000 us-gaap_FiniteLivedIntangibleAssetsNet |  |  | 22,610,000 us-gaap_FiniteLivedIntangibleAssetsNet |  | 22,610,000 us-gaap_FiniteLivedIntangibleAssetsNet
Finite-Lived Intangible Assets, Accumulated Amortization |  | 6,731,000 us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization | 1,865,000 us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization |  |  | 1,865,000 us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization |  | 1,865,000 us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
Finite-Lived Intangible Asset, Useful Life |  | 5 years |  |  |  |  |  |
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months |  | 4,895,000 us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths |  |  |  |  |  |
Finite-Lived Intangible Assets, Amortization Expense, Year Four |  | 3,058,000 us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour |  |  |  |  |  |
Depreciation, Depletion and Amortization |  | 650,000 us-gaap_DepreciationDepletionAndAmortization | 576,000 us-gaap_DepreciationDepletionAndAmortization | 503,000 us-gaap_DepreciationDepletionAndAmortization |  |  |  |
Liability for Uncertain Tax Positions, Noncurrent |  | 3,244,000 us-gaap_LiabilityForUncertainTaxPositionsNoncurrent |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period |  | 10 years |  |  |  |  |  |
Net of Taxes [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net |  |  | (1,051,000)us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNet / us-gaap_StatementScenarioAxis = djco_NetOfTaxesMember |  |  |  |  |
Daily Journal Consolidated [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Management Incentive Plan Total Amount Paid |  | 0 djco_ManagementIncentivePlanTotalAmountPaid / us-gaap_StatementBusinessSegmentsAxis = djco_DailyJournalConsolidatedMember | 241,240 djco_ManagementIncentivePlanTotalAmountPaid / us-gaap_StatementBusinessSegmentsAxis = djco_DailyJournalConsolidatedMember | 701,520 djco_ManagementIncentivePlanTotalAmountPaid / us-gaap_StatementBusinessSegmentsAxis = djco_DailyJournalConsolidatedMember |  |  |  |
Management Incentive Plan Total Percentage of Pre Tax Earnings |  | 8.20%djco_ManagementIncentivePlanTotalPercentageOfPreTaxEarnings / us-gaap_StatementBusinessSegmentsAxis = djco_DailyJournalConsolidatedMember | 8.20%djco_ManagementIncentivePlanTotalPercentageOfPreTaxEarnings / us-gaap_StatementBusinessSegmentsAxis = djco_DailyJournalConsolidatedMember | 8.20%djco_ManagementIncentivePlanTotalPercentageOfPreTaxEarnings / us-gaap_StatementBusinessSegmentsAxis = djco_DailyJournalConsolidatedMember |  |  |  |
Daily Journal Non-Consolidated [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Management Incentive Plan Total Amount Paid |  | 265,490 djco_ManagementIncentivePlanTotalAmountPaid / us-gaap_StatementBusinessSegmentsAxis = djco_DailyJournalNonConsolidatedMember | 351,120 djco_ManagementIncentivePlanTotalAmountPaid / us-gaap_StatementBusinessSegmentsAxis = djco_DailyJournalNonConsolidatedMember | 513,500 djco_ManagementIncentivePlanTotalAmountPaid / us-gaap_StatementBusinessSegmentsAxis = djco_DailyJournalNonConsolidatedMember |  |  |  |
Management Incentive Plan Total Percentage of Pre Tax Earnings |  | 3.85%djco_ManagementIncentivePlanTotalPercentageOfPreTaxEarnings / us-gaap_StatementBusinessSegmentsAxis = djco_DailyJournalNonConsolidatedMember | 3.66%djco_ManagementIncentivePlanTotalPercentageOfPreTaxEarnings / us-gaap_StatementBusinessSegmentsAxis = djco_DailyJournalNonConsolidatedMember | 3.60%djco_ManagementIncentivePlanTotalPercentageOfPreTaxEarnings / us-gaap_StatementBusinessSegmentsAxis = djco_DailyJournalNonConsolidatedMember |  |  |  |
Sustain Technologies, Inc. [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Management Incentive Plan Total Amount Paid |  | 0 djco_ManagementIncentivePlanTotalAmountPaid / us-gaap_StatementBusinessSegmentsAxis = djco_SustainTechnologiesIncMember | 0 djco_ManagementIncentivePlanTotalAmountPaid / us-gaap_StatementBusinessSegmentsAxis = djco_SustainTechnologiesIncMember | 0 djco_ManagementIncentivePlanTotalAmountPaid / us-gaap_StatementBusinessSegmentsAxis = djco_SustainTechnologiesIncMember |  |  |  |
Management Incentive Plan Total Percentage of Pre Tax Earnings |  | 9.25%djco_ManagementIncentivePlanTotalPercentageOfPreTaxEarnings / us-gaap_StatementBusinessSegmentsAxis = djco_SustainTechnologiesIncMember | 7.95%djco_ManagementIncentivePlanTotalPercentageOfPreTaxEarnings / us-gaap_StatementBusinessSegmentsAxis = djco_SustainTechnologiesIncMember | 8.23%djco_ManagementIncentivePlanTotalPercentageOfPreTaxEarnings / us-gaap_StatementBusinessSegmentsAxis = djco_SustainTechnologiesIncMember |  |  |  |
Maximum [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Property, Plant and Equipment, Useful Life |  | 39 years |  |  |  |  |  |
Minimum [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Property, Plant and Equipment, Useful Life |  | 3 years |  |  |  |  |  |
Building and Building Improvements [Member] | Maximum [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Property, Plant and Equipment, Useful Life |  | 39 years |  |  |  |  |  |
Building and Building Improvements [Member] | Minimum [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Property, Plant and Equipment, Useful Life |  | 5 years |  |  |  |  |  |
Machinery and Equipment [Member] | Maximum [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Property, Plant and Equipment, Useful Life |  | 10 years |  |  |  |  |  |
Machinery and Equipment [Member] | Minimum [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Property, Plant and Equipment, Useful Life |  | 3 years |  |  |  |  |  |
Furniture, Office Equipment, and Software [Member] | Maximum [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Property, Plant and Equipment, Useful Life |  | 5 years |  |  |  |  |  |
Furniture, Office Equipment, and Software [Member] | Minimum [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Property, Plant and Equipment, Useful Life |  | 3 years |  |  |  |  |  |
Customer Relationships [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Finite-Lived Intangible Assets, Net |  | 15,946,000 us-gaap_FiniteLivedIntangibleAssetsNet / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_CustomerRelationshipsMember | 20,310,000 us-gaap_FiniteLivedIntangibleAssetsNet / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_CustomerRelationshipsMember |  |  | 20,310,000 us-gaap_FiniteLivedIntangibleAssetsNet / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_CustomerRelationshipsMember |  | 20,310,000 us-gaap_FiniteLivedIntangibleAssetsNet / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_CustomerRelationshipsMember
Finite-Lived Intangible Assets, Accumulated Amortization |  | 6,004,000 us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_CustomerRelationshipsMember | 1,640,000 us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_CustomerRelationshipsMember |  |  | 1,640,000 us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_CustomerRelationshipsMember |  | 1,640,000 us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_CustomerRelationshipsMember
Developed Technology Rights [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Finite-Lived Intangible Assets, Net |  | 1,798,000 us-gaap_FiniteLivedIntangibleAssetsNet / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_DevelopedTechnologyRightsMember | 2,300,000 us-gaap_FiniteLivedIntangibleAssetsNet / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_DevelopedTechnologyRightsMember |  |  | 2,300,000 us-gaap_FiniteLivedIntangibleAssetsNet / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_DevelopedTechnologyRightsMember |  | 2,300,000 us-gaap_FiniteLivedIntangibleAssetsNet / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_DevelopedTechnologyRightsMember
Finite-Lived Intangible Assets, Accumulated Amortization |  | 727,000 us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_DevelopedTechnologyRightsMember | 225,000 us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_DevelopedTechnologyRightsMember |  |  | 225,000 us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_DevelopedTechnologyRightsMember |  | 225,000 us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_DevelopedTechnologyRightsMember
Management Incentive Plan, Future Commitment [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Other Accrued Liabilities |  | 780,000 us-gaap_OtherAccruedLiabilitiesCurrentAndNoncurrent / us-gaap_FairValueByLiabilityClassAxis = djco_ManagementIncentivePlanFutureCommitmentMember | 1,620,000 us-gaap_OtherAccruedLiabilitiesCurrentAndNoncurrent / us-gaap_FairValueByLiabilityClassAxis = djco_ManagementIncentivePlanFutureCommitmentMember |  |  | 1,620,000 us-gaap_OtherAccruedLiabilitiesCurrentAndNoncurrent / us-gaap_FairValueByLiabilityClassAxis = djco_ManagementIncentivePlanFutureCommitmentMember |  | 1,620,000 us-gaap_OtherAccruedLiabilitiesCurrentAndNoncurrent / us-gaap_FairValueByLiabilityClassAxis = djco_ManagementIncentivePlanFutureCommitmentMember
Increase (Decrease) in Other Accrued Liabilities |  | (840,000)us-gaap_IncreaseDecreaseInOtherAccruedLiabilities / us-gaap_FairValueByLiabilityClassAxis = djco_ManagementIncentivePlanFutureCommitmentMember | 2,580,000 us-gaap_IncreaseDecreaseInOtherAccruedLiabilities / us-gaap_FairValueByLiabilityClassAxis = djco_ManagementIncentivePlanFutureCommitmentMember |  |  |  |  |
Other Accrued Liabilities Impact on Earnings Per Share |  | $ 0.61 djco_OtherAccruedLiabilitiesImpactOnEarningsPerShare / us-gaap_FairValueByLiabilityClassAxis = djco_ManagementIncentivePlanFutureCommitmentMember | $ 1.87 djco_OtherAccruedLiabilitiesImpactOnEarningsPerShare / us-gaap_FairValueByLiabilityClassAxis = djco_ManagementIncentivePlanFutureCommitmentMember |  |  |  |  |
Sales Revenue, Net [Member] | Product Concentration Risk [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Concentration Risk, Percentage |  | 53.00%us-gaap_ConcentrationRiskPercentage1 / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_SalesRevenueNetMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_ProductConcentrationRiskMember | 37.00%us-gaap_ConcentrationRiskPercentage1 / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_SalesRevenueNetMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_ProductConcentrationRiskMember | 9.00%us-gaap_ConcentrationRiskPercentage1 / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_SalesRevenueNetMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_ProductConcentrationRiskMember |  |  |  |
ISD Corporation [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Goodwill |  |  |  |  |  |  | 1,700,000 us-gaap_Goodwill / us-gaap_BusinessAcquisitionAxis = djco_ISDMember |
Payments to Acquire Businesses, Gross |  |  |  |  | 16,000,000 us-gaap_PaymentsToAcquireBusinessesGross / us-gaap_BusinessAcquisitionAxis = djco_ISDMember |  |  |
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual |  |  | 784,000 us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual / us-gaap_BusinessAcquisitionAxis = djco_ISDMember |  |  | 784,000 us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual / us-gaap_BusinessAcquisitionAxis = djco_ISDMember |  |
Business Combination Pro Forma Information Expenses Since Acquisition Date Actual |  |  | 694,000 djco_BusinessCombinationProFormaInformationExpensesSinceAcquisitionDateActual / us-gaap_BusinessAcquisitionAxis = djco_ISDMember |  |  | 694,000 djco_BusinessCombinationProFormaInformationExpensesSinceAcquisitionDateActual / us-gaap_BusinessAcquisitionAxis = djco_ISDMember |  |
Amortization of Intangible Assets |  |  | 278,000 us-gaap_AmortizationOfIntangibleAssets / us-gaap_BusinessAcquisitionAxis = djco_ISDMember |  |  | 278,000 us-gaap_AmortizationOfIntangibleAssets / us-gaap_BusinessAcquisitionAxis = djco_ISDMember |  |
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual |  |  |  |  |  | 90,000 us-gaap_BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual / us-gaap_BusinessAcquisitionAxis = djco_ISDMember |  |
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed Tangible Assets |  |  |  |  |  |  | 4,410,000 djco_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedTangibleAssets / us-gaap_BusinessAcquisitionAxis = djco_ISDMember |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents |  |  |  |  |  |  | 2,546,000 us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents / us-gaap_BusinessAcquisitionAxis = djco_ISDMember |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables |  |  |  |  |  |  | 1,636,000 us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables / us-gaap_BusinessAcquisitionAxis = djco_ISDMember |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment |  |  |  |  |  |  | 141,000 us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment / us-gaap_BusinessAcquisitionAxis = djco_ISDMember |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets |  |  |  |  |  |  | 87,000 us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets / us-gaap_BusinessAcquisitionAxis = djco_ISDMember |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles |  |  |  |  |  |  | 14,975,000 us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles / us-gaap_BusinessAcquisitionAxis = djco_ISDMember |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities |  |  |  |  |  |  | 5,112,000 us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities / us-gaap_BusinessAcquisitionAxis = djco_ISDMember |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other |  |  |  |  |  |  | 2,270,000 us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther / us-gaap_BusinessAcquisitionAxis = djco_ISDMember |
ISD Corporation [Member] | Deferred Maintenance Agreement [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Deferred Revenue |  |  |  |  |  |  | 2,842,000 us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesDeferredRevenue / us-gaap_BusinessAcquisitionAxis = djco_ISDMember / us-gaap_FairValueByLiabilityClassAxis = djco_DeferredMaintenanceAgreementMember |
New Dawn [Member] |  |  |  |  |  |  |  |
Accounting Policies [Abstract] |  |  |  |  |  |  |  |
Payments to Acquire Businesses, Gross |  |  |  |  |  |  | 14,000,000 us-gaap_PaymentsToAcquireBusinessesGross / us-gaap_BusinessAcquisitionAxis = djco_NewDawnMember |
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual |  |  |  |  |  |  |  | 10,403,000 us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual / us-gaap_BusinessAcquisitionAxis = djco_NewDawnMember
Business Combination Pro Forma Information Expenses Since Acquisition Date Actual |  |  |  |  |  |  |  | 10,625,000 djco_BusinessCombinationProFormaInformationExpensesSinceAcquisitionDateActual / us-gaap_BusinessAcquisitionAxis = djco_NewDawnMember
Amortization of Intangible Assets |  |  |  |  |  |  |  | 1,587,000 us-gaap_AmortizationOfIntangibleAssets / us-gaap_BusinessAcquisitionAxis = djco_NewDawnMember
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual |  |  |  |  |  |  |  | 222,000 us-gaap_BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual / us-gaap_BusinessAcquisitionAxis = djco_NewDawnMember
Business Acquisition, Transaction Costs |  |  |  |  | 202,000 us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts / us-gaap_BusinessAcquisitionAxis = djco_NewDawnMember |  | 96,000 us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts / us-gaap_BusinessAcquisitionAxis = djco_NewDawnMember |
Liability for Uncertain Tax Positions, Noncurrent |  | $ 3,244,000 us-gaap_LiabilityForUncertainTaxPositionsNoncurrent / us-gaap_BusinessAcquisitionAxis = djco_NewDawnMember |  |  |  |  |  |

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Data Type: | xbrli:monetaryItemType
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Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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- Definition Represents the total percentage of pre-tax income paid to all participants of a specific type of incentive certificate, under DJC Management Incentive Plan. + References No definition available. + Details
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Namespace Prefix: | djco_
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