Stock Compensation (Schedule Of Stock Grant Activity For PSUs) (Details) - Performance Stock Units (PSUs) [Member] - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested, Beginning Balance, Shares	347,000	147,000	169,000
Granted, Shares	70,000	322,000	104,000
Vested, Shares	(55,000)	(87,000)	(109,000)
Forfeited, Shares	(31,000)	(35,000)	(17,000)
Unvested, Ending Balance, Shares	331,000	347,000	147,000	169,000
Vested and expected to vest, Shares	331,000
Outstanding, Weighted Average Remaining Contractual Term in Years	1 year 7 months 20 days	2 years 3 months 29 days	8 months 19 days	8 months 15 days
Vested and expected to vest, Weighted Average Remaining Contractual Term in Years	1 year 7 months 20 days
Outstanding, Aggregate Intrinsic Value	$ 7,805,000	$ 9,400,000	$ 4,179,000	$ 3,236,000
Vested and expected to vest, Aggregate Intrinsic Value	$ 7,805,000