Share-based Compensation and Non-Qualified Deferred Compensation Plan (Summary Of Share Options Outstanding And Exercisable) (Details) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2015 USD ($) $ / shares shares
Outstanding and Exercisable Options, Number | shares	295,205	[1]
Aggregate intrinsic value of outstanding options | $	$ 9.3
Aggregate Intrinsic Value of Exercisable Options | $	$ 9.3
Closing share price per share for calculation of aggregate intrinsic values	$ 73.90
Options outstanding at September 30, 2015, Weighted Average Exercise/Grant Price	42.49	[1]
Exercise Price Thirty Point Zero Six Member [Domain]
Range of exercise prices, minimum	30.06
Range of exercise prices, maximum	$ 30.06
Outstanding and Exercisable Options, Number | shares	105,015	[1]
Outstanding and Exercisable Options, Weighted Average Price	$ 30.06	[1]
Range Of Exercise Prices Forty One Point Sixteen To Forty Three Point Ninety Four [Domain]
Range of exercise prices, minimum	41.16
Range of exercise prices, maximum	$ 43.94
Outstanding and Exercisable Options, Number | shares	119,242	[1]
Outstanding and Exercisable Options, Weighted Average Price	$ 42.46	[1]
Range Of Exercise Prices Forty Eight Point Zero Two To Seventy Five Point Seventeen Member [Domain] [Domain]
Range of exercise prices, minimum	48.02
Range of exercise prices, maximum	$ 75.17
Outstanding and Exercisable Options, Number | shares	70,948	[1]
Outstanding and Exercisable Options, Weighted Average Price	$ 60.92	[1]

[1] The aggregate intrinsic value of options outstanding and exercisable at September 30, 2015 was $9.3 million. The aggregate intrinsic value was calculated as the excess, if any, between our closing share price of $73.90 per share on September 30, 2015 and the strike price of the underlying award.