v2.4.0.8

Realized and Net Change in Unrealized Gains (Losses) on Investments Held by Blackstone's Treasury Cash Management Strategies (Detail) (Blackstone's Treasury Cash Management Strategies, USD $) In Thousands, unless otherwise specified | 12 Months Ended
--- | ---
Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011
Blackstone's Treasury Cash Management Strategies |  |  |
Gain (Loss) on Investments [Line Items] |  |  |
Realized Gains (Losses) | $ (5,793) | $ 9,095 | $ 9,738
Net Change in Unrealized Gains (Losses) | (9,342) | (502) | 641
Total realized and net change in unrealized gains (losses) | $ (15,135) | $ 8,593 | $ 10,379

X
- Definition Net Changes In Unrealized Gains Losses On Investments Held By Treasury Cash Management Strategies + References No definition available. + Details
Name: | bx_NetChangesInUnrealizedGainsLossesOnInvestmentsHeldByTreasuryCashManagementStrategies
Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Realized Gains Losses On Investments Held By Treasury Cash Management Strategies + References No definition available. + Details
Name: | bx_RealizedGainsLossesOnInvestmentsHeldByTreasuryCashManagementStrategies
Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Total Realized Gains Losses and Net Change In Unrealized Gains Losses On Investments Held By Treasury Cash Management Strategies + References No definition available. + Details
Name: | bx_TotalRealizedGainsLossesAndNetChangeInUnrealizedGainsLossesOnInvestmentsHeldByTreasuryCashManagementStrategies
Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration