Summary of Activity in Allowance for Losses on Residential Loans (Detail) (Residential Loans, USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Residential Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	$ 29,064	$ 59,155	$ 28,504	$ 66,881
Charge-offs, net	(1,751)	(1,991)	(2,545)	(5,139)
Reversal of provision for loan losses	(4,163)	(1,715)	(2,809)	(1,715)
Deconsolidation adjustment				(4,578)
Balance at End of Period	$ 23,150	$ 55,449	$ 23,150	$ 55,449