Schedule of ARM Securities Forward Purchase Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Derivative [Line Items]
Forward purchase agreements - Face/UPB	$ 2,826,769	$ 3,808,687
Forward purchase agreements - Cost	2,911,197	3,927,034
Forward purchase agreements - Fair Value	2,879,014	3,943,097
Forward purchase agreements - Net Asset (Liability)	(32,183)	16,063
ARMs - Originators
Derivative [Line Items]
Forward purchase agreements - Face/UPB	145,246	376,936
Forward purchase agreements - Cost	147,749	384,673
Forward purchase agreements - Fair Value	147,914	388,829
Forward purchase agreements - Net Asset (Liability)	165	4,156
ARMs - Dealers
Derivative [Line Items]
Forward purchase agreements - Face/UPB		20,095
Forward purchase agreements - Cost		20,553
Forward purchase agreements - Fair Value		20,517
Forward purchase agreements - Net Asset (Liability)		(36)
Fixed-rate TBA Dollar Roll Securities
Derivative [Line Items]
Forward purchase agreements - Face/UPB	2,655,000	3,400,000
Forward purchase agreements - Cost	2,736,748	3,509,871
Forward purchase agreements - Fair Value	2,704,375	3,521,816
Forward purchase agreements - Net Asset (Liability)	(32,373)	11,945
Whole Mortgage Loans
Derivative [Line Items]
Forward purchase agreements - Face/UPB	26,523	11,656
Forward purchase agreements - Cost	26,700	11,937
Forward purchase agreements - Fair Value	26,725	11,935
Forward purchase agreements - Net Asset (Liability)	$ 25	$ (2)