Earnings per Share (Reconciliation of Denominator for Basic and Diluted Earnings Per Share) (Details) (USD $)	0 Months Ended	3 Months Ended				9 Months Ended
	Feb. 14, 2014	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Earnings Per Share [Abstract]
Basic		133,299,458	[1]	133,257,494	[1]	133,199,304	[1]	133,256,054	[1]
Plus incremental shares from: Assumed exercise of options		546,601	[1]	553,614	[1]	543,841	[1]	550,704	[1]
Weighted average common shares-diluted		133,846,059	[1]	133,811,108	[1]	133,743,145	[1]	133,806,758	[1]
Earnings per share: Basic		$ 1.26	[1]	$ 1.28	[1]	$ 3.71	[1]	$ 3.29	[1]
Earnings per share: Diluted		$ 1.25	[1]	$ 1.27	[1]	$ 3.69	[1]	$ 3.27	[1]
Stock split conversion ratio	2

[1] Share amounts and per share data for the three and nine months ended September 30, 2013 have been restated to reflect the effect of a two-for-one stock split on March 18, 2014. See Note 1 for additional information.