Share-based Compensation and Non-Qualified Deferred Compensation Plan (Summary Of Share Incentive Plans) (Details)	9 Months Ended
	Sep. 30, 2015 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding Options, Number At December 31, 2014	321,811
Granted, Options Outstanding	26,752
Exercised/Vested, Options Outstanding	(53,358)
Forfeited, Options Outstanding	0
Outstanding Options, Number At September 30, 2015	295,205
Options outstanding at December 31, 2014, Weighted Average Exercise/Grant Price | $ / shares	$ 38.97
Granted, Weighted Average Exercise/Grant Price | $ / shares	75.17
Exercised/Vested, Weighted Average Exercise/Grant Price | $ / shares	37.69
Forfeited, Weighted Average Exercise/Grant Price | $ / shares	0.00
Options outstanding at September 30, 2015, Weighted Average Exercise/Grant Price | $ / shares	$ 42.49	[1]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested share awards outstanding at December 31, 2014, Share Awards Outstanding	818,943
Granted, Share Awards Outstanding	256,599
Exercised/Vested, Share Awards Outstanding	(299,806)
Forfeited, Share Awards Outstanding	(9,297)
Nonvested share awards outstanding at September 30, 2015, Share Awards Outstanding	766,439
Nonvested share awards outstanding at December 31, 2014, Weighted Average Exercise/Grant Price | $ / shares	$ 63.39
Granted, Weighted Average Exercise/Grant Price | $ / shares	74.53
Exercised/Vested, Weighted Average Exercise/Grant Price | $ / shares	60.42
Forfeited, Weighted Average Exercise/Grant Price | $ / shares	67.78
Nonvested share awards outstanding at September 30, 2015, Weighted Average Exercise/Grant Price | $ / shares	$ 68.22

[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.