Stock-Based Compensation (Summary Of SAR Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Stock Appreciation Rights [Roll Forward]
Outstanding, Shares	1,022,568	1,049,816
Granted, Shares	103,210
Forfeited, Shares	(501)
Expired, Shares	(78)
Exercised, Shares	(129,879)
Outstanding, Weighted Average Exercise Price, Beginning Balance	$ 43.55
Granted, Weighted Average Exercise Price	63.18
Forfeited, Weighted Average Exercise Price	53.29
Expired, Weighted Average Exercise Price	54.33
Exercised, Weighted Average Exercise Price	33.65
Outstanding, Weighted Average Exercise Price, Ending Balance	$ 46.79
Outstanding, Weighted Average Remaining Contractual Term (in years)	6 years 10 months 24 days
Outstanding, Aggregate Intrinsic Value, Ending Balance	$ 7,089