Share-Based Compensation (Summary Of Stock Appreciation Rights) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Realized tax benefit	$ 4,664,000	$ 3,848,000	$ 629,000
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding at beginning of period	283,221
Exercised	(175,990)
Outstanding at ending of period	107,231	283,221
Exercisable at ending of period	107,231
Weighted-Average Exercise Price, Outstanding at beginning of period	$ 28.92
Weighted-Average Exercise Price, Exercised	$ 28.92
Weighted-Average Exercise Price, Exercisable at ending of period	$ 28.92
Outstanding, Weighted Average Remaining Contractual Term	5 years 40 days
Exercisable, Weighted Average Remaining Contractual Term	5 years 40 days
Outstanding, Intrinsic Value	2,173,000
Exercisable, Intrinsic Value	2,173,000
Cash paid to settle exercisable SARs	3,623,000	2,382,000	51,000
Realized tax benefit	1,388,000	929,000	20,000
Accrued liability for cash-settled SARs	$ 2,200,000	$ 4,300,000
Weighted-average fair value per SAR	$ 20.97	$ 15.13