Stock-Based Compensation (Summary Of SAR Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Stock Appreciation Rights [Roll Forward]
Outstanding, Shares	1,118,714	1,066,438
Granted, Shares	186,943
Forfeited, Shares	(5,383)
Expired, Shares	(1,837)
Exercised, Shares	(127,447)
Outstanding, Weighted Average Exercise Price, Beginning Balance	$ 40.22
Granted, Weighted Average Exercise Price	61.76
Forfeited, Weighted Average Exercise Price	52.00
Expired, Weighted Average Exercise Price	38.88
Exercised, Weighted Average Exercise Price	34.10
Outstanding, Weighted Average Exercise Price, Ending Balance	$ 44.47
Outstanding, Weighted Average Remaining Contractual Term (in years)	6 years 8 months 12 days
Outstanding, Aggregate Intrinsic Value, Ending Balance	$ 18,310