Schedule I - Parent Company Only Financial Statements - Statements of Financial Condition (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Assets
Cash and cash equivalents	$ 716,919	$ 388,409	$ 369,713	$ 364,104
Receivables from related parties	15,211	21,655
Other assets	174,984	101,536
Total assets	2,079,363	1,638,939
Liabilities and Stockholders' Equity
Payables to related parties	15,382	40,700
Accounts payable, accrued and other liabilities	392,525	260,462
Notes payable and collateralized borrowings	258,356	301,444
Total liabilities	1,309,698	1,132,688
Commitments and contingencies
Total stockholders' equity	464,368	334,292
Total liabilities, redeemable partnership interest, and equity	2,079,363	1,638,939
Parent Company [Member]
Assets
Cash and cash equivalents	67	27		52
Investments in subsidiaries	410,778	431,536
Receivables from related parties	229,018	53,621
Note receivable from related party	406,775	413,839
Other assets	70,362	16,387
Total assets	1,117,000	915,410
Liabilities and Stockholders' Equity
Payables to related parties	191,708	145,177
Accounts payable, accrued and other liabilities	54,149	22,102
Notes payable and collateralized borrowings	256,775	263,839
Notes payable to related parties	150,000	150,000
Total liabilities	652,632	581,118
Commitments and contingencies
Total stockholders' equity	464,368	334,292
Total liabilities, redeemable partnership interest, and equity	$ 1,117,000	$ 915,410