Derivative Instruments And Hedging Activities (Schedule Of Derivative Instruments In Consolidated Statements Of Operations) (Details) - Cash Flow Interest Rate Contracts [Member] - Interest Expense [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(Loss) Recognized in OCI (Effectiveness)	$ 1,085	$ 6,383	$ (2,137)
Loss Reclassified From OCI Into Income	$ 635	5,444	$ 3,824
Loss Recognized Due to Ineffectiveness		$ 30