Derivatives (Offsetting Derivatives Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Derivative Assets
Derivatives assets, net amounts of assets presented in the statement of financial position	$ 19,145	$ 32,256
Interest Rate Swap
Derivative Assets
Derivative assets, gross amounts of recognized assets	12,206	26,081
Derivative asset, fair value, gross liability	0	0
Derivatives assets, net amounts of assets presented in the statement of financial position	12,206	26,081
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative assets, gross amounts not offset in the statement of financial position, financial instruments	(12,206)	(7,229)
Derivative assets, gross amounts not offset in the statement of financial position, collateral posted	0	0
Derivative assets, net amount	0	18,852
Foreign Exchange Contract
Derivative Assets
Derivative assets, gross amounts of recognized assets	52	1,137
Derivative asset, fair value, gross liability	0	0
Derivatives assets, net amounts of assets presented in the statement of financial position	52	1,137
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative assets, gross amounts not offset in the statement of financial position, financial instruments	0	0
Derivative assets, gross amounts not offset in the statement of financial position, collateral posted	0	0
Derivative assets, net amount	$ 52	$ 1,137