Derivative Instruments Schedule of TBA Securities (Details) - USD ($) $ in Thousands		Jun. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Financial derivatives–assets, at fair value	[1]	$ 6,106	$ 6,008
Financial derivatives–liabilities, at fair value	[1]	(2,686)	(1,975)
Derivative, Fair Value, Net		3,420	4,033
TBA securities- purchase contracts [Member]
Derivative [Line Items]
Derivative notional	[2]	126,309	49,138
Derivative cost basis	[3]	132,095	49,774
Market Value, Underyling	[4]	131,767	49,870
Derivative, Fair Value, Net	[5]	(328)	96
TBA securities- sale contracts [Member]
Derivative [Line Items]
Derivative notional	[2]	(674,414)	(465,036)
Derivative cost basis	[3]	(705,636)	(488,501)
Market Value, Underyling	[4]	(703,701)	(488,106)
Derivative, Fair Value, Net	[5]	1,935	395
TBA securities [Member]
Derivative [Line Items]
Derivative notional, net	[2]	(548,105)	(415,898)
Derivative cost basis	[3]	(573,541)	(438,727)
Market Value, Underyling	[4]	(571,934)	(438,236)
Derivative, Fair Value, Net	[5]	1,607	491
Derivative Financial Instruments, Assets [Member] | TBA securities- purchase contracts [Member]
Derivative [Line Items]
Derivative notional	[2]	0	49,138
Derivative cost basis	[3]	0	49,774
Market Value, Underyling	[4]	0	49,870
Financial derivatives–assets, at fair value	[5]	0	96
Derivative Financial Instruments, Assets [Member] | TBA securities- sale contracts [Member]
Derivative [Line Items]
Derivative notional	[2]	(672,314)	(281,655)
Derivative cost basis	[3]	(703,405)	(298,807)
Market Value, Underyling	[4]	(701,469)	(297,858)
Financial derivatives–assets, at fair value	[5]	1,936	949
Derivative Financial Instruments, Liabilities [Member] | TBA securities- purchase contracts [Member]
Derivative [Line Items]
Derivative notional	[2]	126,309	0
Derivative cost basis	[3]	132,095	0
Market Value, Underyling	[4]	131,767	0
Financial derivatives–liabilities, at fair value	[5]	(328)	0
Derivative Financial Instruments, Liabilities [Member] | TBA securities- sale contracts [Member]
Derivative [Line Items]
Derivative notional	[2]	(2,100)	(183,381)
Derivative cost basis	[3]	(2,231)	(189,694)
Market Value, Underyling	[4]	(2,232)	(190,248)
Financial derivatives–liabilities, at fair value	[5]	$ (1)	$ (554)

[1] In the Company's Consolidated Balance Sheet, all balances associated with the repurchase agreements and financial derivatives are presented on a gross basis.

[2] Notional amount represents the principal balance of the underlying Agency RMBS.

[3] Cost basis represents the forward price to be paid (received) for the underlying Agency RMBS.

[4] Market value represents the current market value of the underlying Agency RMBS (on a forward delivery basis) as of period end.

[5] Net carrying value represents the difference between the market value of the TBA contract as of period end and the cost basis and is reported in Financial derivatives-assets at fair value and Financial derivatives-liabilities at fair value on the Consolidated Balance Sheet.