Earnings Per Share (Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Net income	$ 22,517	$ 18,920	$ 61,755	$ 57,318
Weighted average common shares outstanding	72,298	72,058	72,239	72,043
Dilutive effect of stock-based awards	303	348	278	321
Shares used in computing diluted earnings per share	72,601	72,406	72,517	72,364
Basic earnings per share	$ 0.31	$ 0.26	$ 0.85	$ 0.80
Diluted earnings per share	$ 0.31	$ 0.26	$ 0.85	$ 0.79
Number of antidilutive options that were excluded from computation of earnings per share	0	0	0	0