Derivatives and Hedging (Summary Of Cash Flow Interest Rate Contract Hedging Activity) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Total Amount of Interest Expense, net Presented in the Condensed Consolidated Statement of Operations	$ (14,672)	$ (21,082)
Cash Flow Hedges [Member] | Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Gain) Loss Recognized in Other Comprehensive Income (Loss) on Derivative	(1,379)	(389)
Interest Expense [Member] | Cash Flow Hedges [Member] | Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income	243	(139)
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income as a Result That a Forecasted Transaction is No Longer Probable of Occurring	$ 3,390	$ 0