Fair Value - Summary of Net Fair Value Gains (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Other net fair value gains (losses)
Assets of Non-Residual Trusts	$ 18,157	$ 18,600	$ 35,013	$ 68,971
Liabilities of Non-Residual Trusts	(15,845)	(17,204)	(29,850)	(61,782)
Mandatory repurchase obligation	566	118	404	(177)
Professional fees liability related to certain securitizations	(210)	(268)	(430)	(554)
Contingent earn-out payments	(1,106)		(4,800)
Other	94	(458)	58	(907)
Other net fair value gains	$ 1,656	$ 788	$ 395	$ 5,551