Deferred Charges, Goodwill And Other Assets, Net (Schedule Of Cash Flow Hedging, Derivative Financial Instruments On The Income Statement) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Total Amount of Interest Expense presented in the consolidated statements	$ (20,612,000)	$ (22,207,000)	$ (41,530,000)	$ (45,688,000)
Designated as Hedging Instrument [Member] | Interest Rate Swaps [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in OCI on Derivative		(2,812,000)		(4,413,000)
Total Amount of Interest Expense presented in the consolidated statements	(20,612,000)	(22,207,000)	(41,530,000)	(45,688,000)
Designated as Hedging Instrument [Member] | Interest Rate Swaps [Member] | Interest Expense [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income		1,297,000	16,000	2,868,000
Designated as Hedging Instrument [Member] | Interest Rate Swaps [Member] | Interest And Other Investment Income (Loss) [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivative and Reclassification for Forecasted Transactions No Longer Probable of Occurring	$ 0	$ 515,000	$ 0	$ 1,794,000