Share-based Compensation and Non-Qualified Deferred Compensation Plan (Summary Of Share Incentive Plans) (Details) - $ / shares		3 Months Ended	9 Months Ended
		Sep. 30, 2016	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding Options, Number At December 31, 2015			295,205
Granted, Options Outstanding		13,000	12,854
Exercised/Vested, Options Outstanding			(202,993)
Forfeited, Options Outstanding			0
Outstanding Options, Number At September 30, 2016		105,066	105,066
Options outstanding at December 31, 2015, Weighted Average Exercise/Grant Price			$ 42.49
Granted, Weighted Average Exercise/Grant Price			85.05
Exercised/Vested, Weighted Average Exercise/Grant Price			42.19
Forfeited, Weighted Average Exercise/Grant Price			0.00
Options outstanding at September 30, 2016, Weighted Average Exercise/Grant Price	[1]	$ 48.27	$ 48.27
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested share awards outstanding at December 31, 2015, Share Awards Outstanding			750,246
Granted, Share Awards Outstanding			269,728
Exercised/Vested, Share Awards Outstanding			(332,806)
Forfeited, Share Awards Outstanding			(15,473)
Nonvested share awards outstanding at September 30, 2016, Share Awards Outstanding		671,695	671,695
Nonvested share awards outstanding at December 31, 2015, Weighted Average Exercise/Grant Price			$ 68.09
Granted, Weighted Average Exercise/Grant Price			74.90
Exercised/Vested, Weighted Average Exercise/Grant Price			67.82
Forfeited, Weighted Average Exercise/Grant Price			70.65
Nonvested share awards outstanding at September 30, 2016, Weighted Average Exercise/Grant Price		$ 70.90	$ 70.90

[1] The aggregate intrinsic value of options outstanding and exercisable at September 30, 2016 was $3.7 million. The aggregate intrinsic value was calculated as the excess, if any, between our closing share price of $83.74 per share on September 30, 2016 and the strike price of the underlying award.