Fair Value of Financial Instruments Recorded basis and Fair Value (Details) - USD ($) $ in Thousands		Jun. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		$ 20,804	$ 5,727
Derivative liabilities, fair value disclosure		48,240	35,898
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		20,804	5,727
Derivative liabilities, fair value disclosure		48,240	35,898
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed securities, Fair Value Disclosure		3,852,883	3,516,239
Mortgage loans held for investment, net, Fair Value Disclosure		29,858	39,700
Derivative assets		20,804	5,727
Repurchase Agreements, Fair Value Disclosure		3,402,964	3,013,110
FHLB advances, Fair Value Disclosure		108,076	0
Non-recourse collateralized financing, Fair Value Disclosure		8,788	10,786
Derivative liabilities, fair value disclosure		48,240	35,898
Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed securities, Fair Value Disclosure		3,852,883	3,516,239
Mortgage loans held for investment, net, Fair Value Disclosure	[1]	25,460	35,024
Derivative assets		20,804	5,727
Repurchase Agreements, Fair Value Disclosure	[2]	3,402,964	3,013,110
FHLB advances, Fair Value Disclosure	[2]	108,076	0
Non-recourse collateralized financing, Fair Value Disclosure	[1]	8,442	10,366
Derivative liabilities, fair value disclosure		$ 48,240	$ 35,898

[1] (1) The Company determines the fair value of its mortgage loans held for investment, net and its non-recourse collateralized financing using internally developed cash flow models with inputs similar to those used to estimate fair value of the Company's Level 3 non-Agency MBS.

[2] (2)The carrying value of repurchase agreements and FHLB advances generally approximates fair value due to their short term maturities