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Summary of Aggregate Notional Amount and Fair Value of Derivative Financial Instruments (Detail) - USD ($) $ in Thousands | Sep. 30, 2015 | Dec. 31, 2014
--- | --- | ---
Derivatives, Fair Value [Line Items] |  |
Derivative Assets, Notional | $ 1,788,783 | $ 719,650
Derivative Liabilities, Notional | 2,092,823 | 1,425,901
Derivative Assets, Fair Value | 6,048 | 15,009
Derivative Liabilities, Fair Value | 30,769 | 30,528
Net Investment Hedges | Foreign Currency Contracts |  |
Derivatives, Fair Value [Line Items] |  |
Derivative Assets, Notional | 140 | 62,078
Derivative Liabilities, Notional | 56,008 |
Derivative Assets, Fair Value |  | 523
Derivative Liabilities, Fair Value | 244 |
Freestanding Derivatives |  |
Derivatives, Fair Value [Line Items] |  |
Derivative Assets, Notional | 1,788,643 | 657,572
Derivative Liabilities, Notional | 2,036,815 | 1,425,901
Derivative Assets, Fair Value | 6,048 | 14,486
Derivative Liabilities, Fair Value | 30,525 | 30,528
Freestanding Derivatives | Credit Default Swap |  |
Derivatives, Fair Value [Line Items] |  |
Derivative Assets, Fair Value |  | 85
Derivative Liabilities, Fair Value | 6,413 | 868
Freestanding Derivatives | Blackstone - Other | Credit Default Swap |  |
Derivatives, Fair Value [Line Items] |  |
Derivative Assets, Notional |  | 19,500
Derivative Liabilities, Notional | 74,000 | 56,000
Derivative Assets, Fair Value |  | 85
Derivative Liabilities, Fair Value | 6,413 | 868
Freestanding Derivatives | Investments Of Consolidated Blackstone Funds | Credit Default Swap |  |
Derivatives, Fair Value [Line Items] |  |
Derivative Liabilities, Notional | 87,088 | 91,372
Derivative Liabilities, Fair Value | 4,454 | 2,514
Freestanding Derivatives | Foreign Currency Contracts | Blackstone - Other |  |
Derivatives, Fair Value [Line Items] |  |
Derivative Assets, Notional | 181,335 | 192,163
Derivative Liabilities, Notional | 210,855 | 148,873
Derivative Assets, Fair Value | 2,443 | 2,798
Derivative Liabilities, Fair Value | 1,849 | 681
Freestanding Derivatives | Foreign Currency Contracts | Investments Of Consolidated Blackstone Funds |  |
Derivatives, Fair Value [Line Items] |  |
Derivative Assets, Notional | 97,169 | 199,364
Derivative Liabilities, Notional | 107,632 | 250,244
Derivative Assets, Fair Value | 2,345 | 8,915
Derivative Liabilities, Fair Value | 5,975 | 21,875
Freestanding Derivatives | Interest Rate Contracts | Blackstone - Other |  |
Derivatives, Fair Value [Line Items] |  |
Derivative Assets, Notional | 1,510,139 | 223,886
Derivative Liabilities, Notional | 1,557,240 | 879,412
Derivative Assets, Fair Value | 1,260 | 407
Derivative Liabilities, Fair Value | $ 11,834 | 4,590
Freestanding Derivatives | Interest Rate Contracts | Investments Of Consolidated Blackstone Funds |  |
Derivatives, Fair Value [Line Items] |  |
Derivative Assets, Notional |  | 22,659
Derivative Assets, Fair Value |  | $ 2,281

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