Derivatives and Hedging (Summary Of Cash Flow Interest Rate Contract Hedging Activity) (Details) - Cash Flow Hedging [Member] - Interest Rate Contracts [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) Loss Recognized in Other Comprehensive Income on Derivative (Effective Portion)	$ (1,063)	$ 3,192	$ (1,946)
Interest Expense, Net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	42	(1,435)	(2,798)
Amount of Gain (Loss) Recognized in Income on Derivative (Ineffective Portion and Amount Excluded from Effectiveness Testing)	$ 0	$ (96)	$ 0