Components of Company's Interest Income and Interest Expense (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Interest income:
Residential Investment Securities		$ 315,717	$ 478,239
Commercial investment portfolio	[1]	70,187	40,336
Reverse repurchase agreements		2,239	539
Total interest income		388,143	519,114
Interest expense:
Repurchase agreements		132,891	102,748
Convertible Senior Notes			23,627
Securitized debt of consolidated VIEs		9,033	2,882
Participation sold		158	159
Other		5,365	4
Total interest expense		147,447	129,420
Net interest income		$ 240,696	$ 389,694

[1] Includes commercial real estate debt, preferred equity and corporate debt.