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INVESTMENTS - Additional Information (Detail) (USD $) In Millions, unless otherwise specified | 6 Months Ended |  |
--- | --- | --- | ---
Jun. 30, 2012 | Jun. 30, 2011 | Jun. 30, 2012 Blackstone's Net Assets | Jun. 30, 2012 Consolidated Blackstone Funds | Dec. 31, 2011 Consolidated Blackstone Funds
Investment [Line Items] |  |  |  |  |
Investments |  |  |  | $ 486.1 | $ 449.6
Threshold of individual investment fair value to net assets, percentage |  |  | 5.00% |  |
Recognized net gains (losses) related to equity method investments | $ 44.0 | $ 183.6 |  |  |

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