Earnings Per Share (Reconciliation Of Denominator For Basic And Diluted Earnings (Loss) Per Share) (Details) (USD $)	3 Months Ended																12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]
Weighted average common shares - basic																	133,111,230	133,224,256	132,578,858
Plus incremental shares from: Assumed exercise of options																	532,184	554,994	704,132
Weighted average common shares - diluted																	133,643,414	133,779,250	133,282,990
Basic	$ 1.38	[1]	$ 1.26	[1]	$ 1.27	[1]	$ 1.18	[1]	$ 1.28	[1],[2]	$ 1.28	[1],[2]	$ 1.09	[1],[2]	$ 0.92	[1],[2]	$ 5.09	$ 4.57	$ 2.89
Diluted	$ 1.37	[1]	$ 1.25	[1]	$ 1.26	[1]	$ 1.18	[1]	$ 1.27	[1],[2]	$ 1.27	[1],[2]	$ 1.09	[1],[2]	$ 0.92	[1],[2]	$ 5.07	$ 4.55	$ 2.88

[1] Basic and diluted earnings per common share ("EPS") for each quarter is computed using the weighted average shares outstanding during that quarter, while EPS for the year is computed using the weighted average shares outstanding for the year. As a result, the sum of the EPS for each of the four quarters may not equal the EPS for the year.

[2] Per share data for the prior year periods have been restated to reflect the effect of a two-for-one stock split. See Note 8 for additional information.