Derivatives (Offsetting Derivatives Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Interest Rate Swap
Derivative Liabilities
Derivative liabilities, gross amounts of recognized liabilities	$ 7,229	$ 34,871
Derivative liabilities, gross amounts offset in the Statement of Financial Position	0	0
Derivatives liabilities, net amounts of liabilities presented in the Statement of Financial Position	7,229	34,871
Derivative Liability, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative liabilities, gross amounts not offset in the Statement of Financial Position, financial instruments	(7,229)	(11,225)
Derivative liabilities, gross amounts not offset in the Statement of Financial Position, collateral posted	0	(23,646)
Derivative liabilities, net amount	0	0
Foreign Exchange Contract
Derivative Liabilities
Derivative liabilities, gross amounts of recognized liabilities	1,492	874
Derivative liabilities, gross amounts offset in the Statement of Financial Position	0	0
Derivatives liabilities, net amounts of liabilities presented in the Statement of Financial Position	1,492	874
Derivative Liability, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative liabilities, gross amounts not offset in the Statement of Financial Position, financial instruments	0	0
Derivative liabilities, gross amounts not offset in the Statement of Financial Position, collateral posted	0	0
Derivative liabilities, net amount	$ 1,492	$ 874