Residential Loans, Net - Schedule of Ending Balance of Allowance for Loan Losses and Recorded Investment in Residential Loans Carried at Amortized Cost by Basis of Impairment (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011
Allowance for loan losses
Loans collectively evaluated for impairment	$ 16,960		$ 19,408
Loans collectively evaluated for impairment and acquired with deteriorated credit quality	1,346		1,027
Total	18,306	19,932	20,435	14,330	13,784	13,824
Recorded investment in residential loans at amortized cost
Loans collectively evaluated for impairment	1,435,108		1,483,389
Loans collectively evaluated for impairment and acquired with deteriorated credit quality	26,905		27,367
Total	$ 1,462,013		$ 1,510,756