Derivative Instruments Schedule of Swaptions (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2014	Sep. 30, 2015
Derivative [Line Items]
Financial derivatives–assets, at fair value	[1]	$ 3,072	$ 1,527
Financial derivatives–liabilities, at fair value	[1]	(8,700)	$ (16,414)
Straddle [Member] | Interest Rate Swaption [Member]
Derivative [Line Items]
Financial derivatives–assets, at fair value		$ 78
Fixed Pay Rate on Derivatives		3.00%
Maturity term of asset underlying derivative contract		10 years
Derivative notional		$ 9,700
Derivative, Remaining Maturity		6 months 15 days

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