Stock-Based Compensation (Summary Of SAR Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Stock Appreciation Rights [Roll Forward]
Outstanding, Shares	1,004,566	1,049,816
Granted, Shares	103,210
Forfeited, Shares	(2,780)
Expired, Shares	(131)
Exercised, Shares	(145,549)
Outstanding, Weighted Average Exercise Price, Beginning Balance	$ 43.55
Granted, Weighted Average Exercise Price	63.18
Forfeited, Weighted Average Exercise Price	58.36
Expired, Weighted Average Exercise Price	56.64
Exercised, Weighted Average Exercise Price	34.49
Outstanding, Weighted Average Exercise Price, Ending Balance	$ 46.84
Outstanding, Weighted Average Remaining Contractual Term (in years)	6 years 8 months 12 days
Outstanding, Aggregate Intrinsic Value, Ending Balance	$ 13,116