Earnings Per Share (Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share [Abstract]
Net income	$ 31,848	$ 25,632	$ 54,990	$ 39,971
Weighted average common shares outstanding	71,945,000	72,091,000	72,005,000	72,382,000
Dilutive effect of stock-based awards	479,000	506,000	477,000	500,000
Shares used in computing diluted earnings per share	72,424,000	72,597,000	72,482,000	72,882,000
Basic earnings per share	$ 0.44	$ 0.36	$ 0.76	$ 0.55
Diluted earnings per share	$ 0.44	$ 0.35	$ 0.76	$ 0.55
Number of antidilutive options that were excluded from computation of earnings per share	0	0	0	0