v2.4.0.8
Summary of Aggregate Notional Amount and Fair Value of Derivative Financial Instruments (Detail) (USD $)
In Thousands, unless otherwise specified
Sep. 30, 2013
Dec. 31, 2012
Derivatives, Fair Value [Line Items]    
Derivative Assets, Notional $ 2,427,718 $ 1,306,817
Derivative Liabilities, Notional 1,379,602 1,035,631
Derivative Assets, Fair Value 80,642 99,374
Derivative Liabilities, Fair Value 19,380 22,070
Freestanding Derivatives | Interest Rate Contracts | Blackstone - Other
   
Derivatives, Fair Value [Line Items]    
Derivative Assets, Notional 1,914,476 689,300
Derivative Liabilities, Notional 1,035,600 636,555
Derivative Assets, Fair Value 44,545 55,270
Derivative Liabilities, Fair Value 4,673 4,116
Freestanding Derivatives | Interest Rate Contracts | Investment Of Consolidated CLO Vehicles
   
Derivatives, Fair Value [Line Items]    
Derivative Assets, Notional 81,505 165,517
Derivative Liabilities, Notional   90,500
Derivative Assets, Fair Value 3,653 6,132
Derivative Liabilities, Fair Value   772
Freestanding Derivatives | Foreign Currency Contracts | Blackstone - Other
   
Derivatives, Fair Value [Line Items]    
Derivative Assets, Notional 68,896 16,771
Derivative Liabilities, Notional 66,115 7,025
Derivative Assets, Fair Value 1,490 74
Derivative Liabilities, Fair Value 1,398 81
Freestanding Derivatives | Foreign Currency Contracts | Investment Of Consolidated CLO Vehicles
   
Derivatives, Fair Value [Line Items]    
Derivative Assets, Notional 362,841 435,229
Derivative Liabilities, Notional 236,887 301,551
Derivative Assets, Fair Value 30,954 37,898
Derivative Liabilities, Fair Value 8,775 17,101
Freestanding Derivatives | Credit Default Swaps | Blackstone - Other
   
Derivatives, Fair Value [Line Items]    
Derivative Liabilities, Notional 41,000  
Derivative Liabilities, Fair Value $ 4,534