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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 | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2015 | Sep. 30, 2014 | Sep. 30, 2015 | Sep. 30, 2014
Gain (Loss) on Investments [Line Items] |  |  |  |
Realized Gains (Losses) | $ (3,003) | $ 2,142 | $ (6,606) | $ 6,307
Net Change in Unrealized Gains (Losses) | (8,984) | (14,541) | (12,922) | 1,551
Total realized and net change in unrealized gains (losses) | $ (11,987) | $ (12,399) | $ (19,528) | $ 7,858

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