Offsetting Assets and Liabilities Offsetting Assets (Details) - USD ($) $ in Thousands		Jun. 30, 2015	Dec. 31, 2014
Offsetting Assets [Line Items]
Derivative assets, fair value, gross asset			$ 5,727
Derivative assets, fair value, gross liability		$ 0	0
Derivative assets, fair value, amount not offset against collateral		20,804	5,727
Derivative assets, Collateral, Obligation to Return Securities	[1]	(2,848)	(1,073)
Derivative assets, Collateral, Obligation to Return Cash	[1]	(17,956)	(4,521)
Derivative assets, fair value, amount offset against collateral		$ 0	$ 133

[1] 1) Amount disclosed for collateral received by or posted to the same counterparty include cash and the fair value of MBS up to and not exceeding the net amount of the asset or liability presented in the balance sheet. The fair value of the actual collateral received by or posted to the same counterparty may exceed the amounts presented.