The Components of Gain (Loss) on Derivative Instruments Net (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Derivative Instruments Gain Loss [Line Items]
Gain (loss) on derivative instruments, net	$ (41,615)	$ 51
Interest Rate Swap
Derivative Instruments Gain Loss [Line Items]
Fair value adjustments	15,863	0
Monthly net settlements	(29,412)	0
Futures Contracts
Derivative Instruments Gain Loss [Line Items]
Fair value adjustments	(17,382)	0
Realized gains (losses)	(18,606)	51
TBA Dollar Roll
Derivative Instruments Gain Loss [Line Items]
TBA dollar roll income	20,821	0
TBA contracts
Derivative Instruments Gain Loss [Line Items]
Realized and unrealized losses	$ (12,899)	$ 0

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Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

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Amount of settlements of financial instrument classified as a derivative asset (liability) after deduction of derivative liability, measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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The net gain (loss) recognized in earnings during the reporting period representing the amount of the cash flow hedges' ineffectiveness.

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Aggregate net gain and losses (whether realized or unrealized) on all derivative instruments held for trading purposes whether or not settled physically.

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The net gain (loss) recognized in earnings during the period due to the ineffectiveness on interest rate fair value hedges.

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Amount of unrealized gain (loss) related to the fair value of interest rate derivatives designated as fair value hedging instruments, as offset by the gain (loss) on the hedged item to the extent that the fair value hedge is determined to be effective.

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