Derivative Financial Instruments Offsetting Derivative Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Offsetting Assets [Line Items]
Derivative asset, fair value	$ 62,818	$ 33,398
Derivative, Collateral, Obligation to Return Securities	335	202
Derivative, Collateral, Obligation to Return Cash	0	0
Net Amount	62,483	33,196
Derivative liability, gross liability	62,816	33,117
Derivative liability, Collateral, Right to Reclaim Securities	(335)	(202)
Derivative liability, Collateral, Right to Reclaim Cash	(58,830)	(31,130)
Derivative liability, Net Amount	3,651	1,785
Interest Rate Swap [Member]
Offsetting Assets [Line Items]
Derivative asset, fair value	62,355	32,970
Derivative, Collateral, Obligation to Return Securities	32	55
Derivative, Collateral, Obligation to Return Cash	0	0
Net Amount	62,323	32,915
Derivative liability, gross liability	62,355	32,970
Derivative liability, Collateral, Right to Reclaim Securities	(32)	(55)
Derivative liability, Collateral, Right to Reclaim Cash	(59,130)	(31,130)
Derivative liability, Net Amount	3,193	1,785
Foreign Exchange Contract [Member]
Offsetting Assets [Line Items]
Derivative asset, fair value	463	428
Derivative, Collateral, Obligation to Return Securities	303	147
Derivative, Collateral, Obligation to Return Cash	0	0
Net Amount	160	281
Derivative liability, gross liability	461	147
Derivative liability, Collateral, Right to Reclaim Securities	(303)	(147)
Derivative liability, Collateral, Right to Reclaim Cash	300	0
Derivative liability, Net Amount	$ 458	$ 0