Derivatives (Offsetting Derivatives Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Derivative Assets
Derivatives assets, net amounts of assets presented in the Statement of Financial Position	$ 32,256	$ 47,501
Interest Rate Swap
Derivative Assets
Derivative assets, gross amounts of recognized assets	26,081	34,701
Derivative asset, fair value, gross liability	0	0
Derivatives assets, net amounts of assets presented in the Statement of Financial Position	26,081	34,701
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative assets, gross amounts not offset in the Statement of Financial Position, financial instruments	(7,229)	(11,225)
Derivative assets, gross amounts not offset in the Statement of Financial Position, collateral posted	0	0
Derivative assets, net amount	18,852	23,476
Foreign Exchange Contract
Derivative Assets
Derivative assets, gross amounts of recognized assets	1,137	670
Derivative asset, fair value, gross liability	0	0
Derivatives assets, net amounts of assets presented in the Statement of Financial Position	1,137	670
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	$ 1,137	$ 670