The Components of Loss on Derivative instruments Net (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Derivative Instruments Gain Loss [Line Items]
Loss on derivative instruments, net	$ (69,715)
Interest Rate Swap
Derivative Instruments Gain Loss [Line Items]
Fair value adjustments	25,036
Monthly net settlements	(30,985)
Futures Contracts
Derivative Instruments Gain Loss [Line Items]
Fair value adjustments	(25,585)
Realized losses	(33,298)
TBA Dollar Roll
Derivative Instruments Gain Loss [Line Items]
TBA dollar roll income	5,605
TBA contracts
Derivative Instruments Gain Loss [Line Items]
Net realized loss	$ (10,488)