Share-based Compensation and Non-Qualified Deferred Compensation Plan (Summary Of Share Incentive Plans) (Details)	3 Months Ended
	Mar. 31, 2016 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding Options, Number At December 31, 2015 | shares	295,205
Granted, Options Outstanding | shares	0
Exercised/Vested, Options Outstanding | shares	0
Forfeited, Options Outstanding | shares	0
Outstanding Options, Number At March 31, 2016 | shares	295,205
Options outstanding at December 31, 2015, Weighted Average Exercise/Grant Price | $ / shares	$ 42.49
Granted, Weighted Average Exercise/Grant Price | $ / shares	0.00
Exercised/Vested, Weighted Average Exercise/Grant Price | $ / shares	0.00
Forfeited, Weighted Average Exercise/Grant Price | $ / shares	0.00
Options outstanding at March 31, 2016, 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, 2015, Share Awards Outstanding | shares	750,246
Granted, Share Awards Outstanding | shares	242,619
Exercised/Vested, Share Awards Outstanding | shares	(312,584)
Forfeited, Share Awards Outstanding | shares	(4,714)
Nonvested share awards outstanding at March 31, 2016, Share Awards Outstanding | shares	675,567
Nonvested share awards outstanding at December 31, 2015, Weighted Average Exercise/Grant Price | $ / shares	$ 68.09
Granted, Weighted Average Exercise/Grant Price | $ / shares	73.63
Exercised/Vested, Weighted Average Exercise/Grant Price | $ / shares	66.96
Forfeited, Weighted Average Exercise/Grant Price | $ / shares	70.00
Nonvested share awards outstanding at March 31, 2016, Weighted Average Exercise/Grant Price | $ / shares	$ 70.59

[1] The aggregate intrinsic value of options outstanding and exercisable at March 31, 2016 was $12.3 million. The aggregate intrinsic value was calculated as the excess, if any, between our closing share price of $84.09 per share on March 31, 2016 and the strike price of the underlying award.