The Components of Loss on Derivative Instruments Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Derivative Instruments Gain Loss [Line Items]
Net gain (loss) on derivative instruments	$ (92,494)	$ (102,785)
Interest Rate Swaps – Net Realized and Unrealized Gains
Derivative Instruments Gain Loss [Line Items]
Net gain (loss) on derivative instruments	(5,942)	1,116
Interest Rate Swaptions
Derivative Instruments Gain Loss [Line Items]
Net gain (loss) on derivative instruments	(721)	(3,027)
Interest Rate Swap
Derivative Instruments Gain Loss [Line Items]
Net gain (loss) on derivative instruments	(5,411)	(21,423)
Futures Contracts - fair value adjustments
Derivative Instruments Gain Loss [Line Items]
Net gain (loss) on derivative instruments	(122,477)	(94,016)
Futures Contracts - Other Realized Losses
Derivative Instruments Gain Loss [Line Items]
Net gain (loss) on derivative instruments	(9,884)	(22,374)
Mortgage Loan Purchase Commitments - Fair Value Adjustments
Derivative Instruments Gain Loss [Line Items]
Net gain (loss) on derivative instruments	(20)	331
TBA Dollar Roll
Derivative Instruments Gain Loss [Line Items]
Net gain (loss) on derivative instruments	17,602	23,155
TBA Dollar Rolls – Net Realized And Unrealized Gains (Losses)
Derivative Instruments Gain Loss [Line Items]
Net gain (loss) on derivative instruments	52,989	20,946
Futures Contracts - Losses From Maturities
Derivative Instruments Gain Loss [Line Items]
Net gain (loss) on derivative instruments	$ (18,630)	$ (7,493)