Derivatives and Hedging (Summary Of Cash Flow Interest Rate Contract Hedging Activity) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Net unrealized gain (loss) on derivatives	$ (1,379)
Net unrealized gain (loss) on derivatives		$ (1,063)	$ 1,204
Interest and Debt Expense	(63,348)	(80,326)	(83,003)
Cash Flow Hedging [Member] | Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net unrealized gain (loss) on derivatives	(1,379)
Net unrealized gain (loss) on derivatives		(1,063)	3,192
Reclassification out of Accumulated Other Comprehensive Income [Member] | Cash Flow Hedging [Member] | Interest Rate Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest and Debt Expense	912	42	(1,435)
Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net	$ 3,390	$ 0	$ (96)