Earnings Per Share (Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Net income	$ 32,076	$ 25,970	$ 87,066	$ 65,941
Weighted average common shares outstanding	71,890,000	71,837,000	71,967,000	72,198,000
Dilutive effect of stock-based awards	588,000	527,000	579,000	508,000
Shares used in computing diluted earnings per share	72,478,000	72,364,000	72,546,000	72,706,000
Basic earnings per share	$ 0.45	$ 0.36	$ 1.21	$ 0.91
Diluted earnings per share	$ 0.44	$ 0.36	$ 1.20	$ 0.91
Number of antidilutive options that were excluded from computation of earnings per share	0	0	0	0