Commitments, Contingencies and Derivatives (Derivatives Effect on Earnings) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Effective portion of unrealized losses recognized within AOCI during the period, net of tax	$ (248)	$ (637)	$ (1,533)
Net reclassification adjustment for effective portion of cash flow hedges included in interest expense, gross(1)	$ 1,592	$ 2,026	$ 1,695