Discontinued Operations - Balance Sheet Disclosures (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
Assets
Cash and cash equivalents	$ 798,712	$ 427,631	$ 423,508	$ 607,689
Other assets	287,015	23,073
Total assets	13,293,295	1,687,536
Liabilities within discontinued operations:
Payable to brokers, dealers and clearing organizations	666,178	24,185
Accrued expenses and other liabilities	220,648	118,068
Total liabilities	11,780,274	721,725
Segment, Discontinued Operations [Member]
Assets
Cash and cash equivalents	15,702
Securitized HECM loan inventory	5,841,664
Loan inventory	177,674
Receivable from brokers, dealers and clearing organizations	37,411
Other assets	25,848
Total assets	6,098,299
Liabilities within discontinued operations:
Liability to GNMA trusts	5,803,859
Other secured financings	129,552
Payable to brokers, dealers and clearing organizations	8,538
Accrued compensation expense	4,717
Accrued expenses and other liabilities	59,358
Total liabilities	$ 6,006,024