Earnings Per Share (Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Earnings Per Share [Abstract]
Net income	$ 20,092	$ 23,142
Weighted average common shares outstanding	72,025,000	72,067,000
Dilutive effect of stock-based awards	328,000	475,000
Shares used in computing diluted earnings per share	72,353,000	72,542,000
Basic earnings per share	$ 0.28	$ 0.32
Diluted earnings per share	$ 0.28	$ 0.32
Number of antidilutive options that were excluded from computation of earnings per share	0	0