Stock Compensation (Summary Of Stock Option Activity) (Details) - Stock Options [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]
Outstanding, Beginning Balance, Shares	1,129,000	1,333,000	1,741,000
Granted, Shares	212,000	169,000	219,000
Exercised, Shares	(88,000)	(334,000)	(578,000)
Forfeited, Shares	(12,000)	(39,000)	(49,000)
Outstanding, Ending Balance, Shares	1,241,000	1,129,000	1,333,000	1,741,000
Vested and expected to vest, Shares	1,241,000
Exercisable, Shares	874,000
Outstanding, Beginning Balance, Weighted Average Exercise Price	$ 16.14	$ 13.04	$ 10.19
Granted, Weighted Average Exercise Price	26.24	29.62	21.55
Exercised, Weighted Average Exercise Price	10.49	9.87	7.59
Forfeited, Weighted Average Exercise Price	27.36	22.64	14.10
Outstanding, Ending Balance, Weighted Average Exercise Price	18.16	$ 16.14	$ 13.04	$ 10.19
Vested and expected to vest, Weighted Average Exercise Price	18.16
Exercisable, Weighted Average Exercise Price	$ 14.71
Outstanding, Weighted Average Remaining Contractual Term in years	3 years 4 months 17 days	3 years 8 months 1 day	3 years 11 months 4 days	3 years 7 months 20 days
Vested and expected to vest, Weighted Average Remaining Contractual Term in Years	3 years 4 months 17 days
Exercisable, Weighted Average Remaining Contractual Term in years	2 years 5 months 12 days
Outstanding, Aggregate Intrinsic Value	$ 8,215,000	$ 12,763,000	$ 20,439,000	$ 15,598,000
Vested and expected to vest, Aggregate Intrinsic Value	8,215,000
Exercisable, Aggregate Intrinsic Value	$ 8,094,000