Summary of Changes in Financial Assets Measured at Fair Value for Which Level III Inputs Were Used (Detail) - Level 3 - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Sep. 30, 2015 |
Sep. 30, 2014 |
Sep. 30, 2015 |
Sep. 30, 2014 |
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| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | |||||||||||||||
| Balance, Beginning of Period | $ 1,125,323 | $ 2,471,097 | $ 2,624,602 | [1] | $ 2,643,469 | [1] | |||||||||
| Transfer In Due to Consolidation and Acquisition | [2] | 205,890 | |||||||||||||
| Transfer In (Out) Due to Deconsolidation | (64,634) | (1,460,538) | (335,357) | ||||||||||||
| Transfer In to Level III | [3] | 49,114 | 181,784 | 72,127 | 302,358 | ||||||||||
| Transfer Out of Level III | [3] | (152,702) | (222,021) | (237,765) | (335,724) | ||||||||||
| Purchases | 271,974 | 255,007 | 492,835 | 662,387 | |||||||||||
| Sales | (142,021) | (239,380) | (370,421) | (862,641) | |||||||||||
| Settlements | (1,545) | (649) | (3,843) | (1,594) | |||||||||||
| Changes in Gains (Losses) Included in Earnings and Other Comprehensive Income (Loss) | 15,265 | 3,449 | 48,411 | 105,865 | |||||||||||
| Balance, End of Period | 1,165,408 | 2,384,653 | 1,165,408 | 2,384,653 | |||||||||||
| Changes in Unrealized Gains (Losses) Included in Earnings Related to Investments Still Held at the Reporting Date | (43,482) | (16,376) | (24,438) | 89,619 | |||||||||||
| Loans and Receivables | |||||||||||||||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | |||||||||||||||
| Balance, Beginning of Period | 36,440 | 42,725 | 40,397 | [1] | 137,788 | [1] | |||||||||
| Purchases | 144,058 | 69,255 | 150,244 | 162,899 | |||||||||||
| Sales | (42,261) | (9,535) | (230,324) | ||||||||||||
| Settlements | (1,405) | (526) | (3,485) | (1,170) | |||||||||||
| Changes in Gains (Losses) Included in Earnings and Other Comprehensive Income (Loss) | 162 | 601 | 1,634 | 601 | |||||||||||
| Balance, End of Period | 179,255 | 69,794 | 179,255 | 69,794 | |||||||||||
| Changes in Unrealized Gains (Losses) Included in Earnings Related to Investments Still Held at the Reporting Date | 162 | 601 | 1,505 | 601 | |||||||||||
| Investments Of Consolidated Funds | |||||||||||||||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | |||||||||||||||
| Balance, Beginning of Period | 937,149 | 2,260,856 | 2,394,821 | [1] | 2,460,908 | [1] | |||||||||
| Transfer In Due to Consolidation and Acquisition | [2] | 205,890 | |||||||||||||
| Transfer In (Out) Due to Deconsolidation | (64,634) | (1,460,538) | (335,357) | ||||||||||||
| Transfer In to Level III | [3] | 43,920 | 161,332 | 47,035 | 273,934 | ||||||||||
| Transfer Out of Level III | [3] | (143,531) | (212,108) | (181,429) | (315,067) | ||||||||||
| Purchases | 122,676 | 165,838 | 304,012 | 346,144 | |||||||||||
| Sales | (139,229) | (190,383) | (321,121) | (618,008) | |||||||||||
| Changes in Gains (Losses) Included in Earnings and Other Comprehensive Income (Loss) | 16,871 | 11,581 | 55,076 | 114,038 | |||||||||||
| Balance, End of Period | 837,856 | 2,132,482 | 837,856 | 2,132,482 | |||||||||||
| Changes in Unrealized Gains (Losses) Included in Earnings Related to Investments Still Held at the Reporting Date | (41,807) | (8,606) | (25,614) | 96,217 | |||||||||||
| Other | |||||||||||||||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | |||||||||||||||
| Balance, Beginning of Period | [4] | 151,734 | 167,516 | 189,384 | [1] | 44,773 | [1] | ||||||||
| Transfer In to Level III | [3],[4] | 5,194 | 20,452 | 25,092 | 28,424 | ||||||||||
| Transfer Out of Level III | [3],[4] | (9,171) | (9,913) | (56,336) | (20,657) | ||||||||||
| Purchases | [4] | 5,240 | 19,914 | 38,579 | 153,344 | ||||||||||
| Sales | [4] | (2,792) | (6,736) | (39,765) | (14,309) | ||||||||||
| Settlements | [4] | (140) | (123) | (358) | (424) | ||||||||||
| Changes in Gains (Losses) Included in Earnings and Other Comprehensive Income (Loss) | [4] | (1,768) | (8,733) | (8,299) | (8,774) | ||||||||||
| Balance, End of Period | [4] | 148,297 | 182,377 | 148,297 | 182,377 | ||||||||||
| Changes in Unrealized Gains (Losses) Included in Earnings Related to Investments Still Held at the Reporting Date | [4] | $ (1,837) | $ (8,371) | $ (329) | $ (7,199) | ||||||||||
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