Share-Based Compensation and Non-Qualified Deferred Compensation Plan (Summary Of Share Options Outstanding And Exercisable) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Dec. 31, 2014
Outstanding and Exercisable Options, Number	295,205	[1]
Aggregate intrinsic value of outstanding options	$ 10.5
Aggregate Intrinsic Value of Exercisable Options	$ 10.5
Closing share price per share for calculation of aggregate intrinsic values	$ 78.13
Options outstanding at December 31, 2014, Weighted Average Exercise/Grant Price			$ 38.97
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	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	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	70,948	[1]
Outstanding and Exercisable Options, Weighted Average Price	$ 60.92	[1]

[1] The aggregate intrinsic value of options outstanding and exercisable at March 31, 2015 was $10.5 million. The aggregate intrinsic value was calculated as the excess, if any, between our closing share price of $78.13 per share on March 31, 2015 and the strike price of the underlying award.