Fair Value - Summary of Components of Net Fair Value Gains on Reverse Loans and Related HMBS Obligations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Net fair value gains (losses) on reverse loans and related HMBS obligations
Interest income on reverse loans	$ 98,258	$ 86,514	$ 195,139	$ 163,781
Change in fair value of reverse loans	(8,687)	14,570	99,841	16,108
Net fair value gains on reverse loans	89,571	101,084	294,980	179,889
Interest expense on HMBS related obligations	(91,470)	(79,545)	(182,030)	(149,220)
Change in fair value of HMBS related obligations	28,835	5,192	(68,778)	32,850
Net fair value gains (losses) on HMBS related obligations	(62,635)	(74,353)	(250,808)	(116,370)
Net fair value gains on reverse loans and related HMBS obligations	$ 26,936	$ 26,731	$ 44,172	$ 63,519