Earnings Per Share (Basic And Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share [Abstract]
Net income	$ 21,259	$ 25,128	$ 64,610	$ 77,053
Weighted average common shares outstanding	72,621,000	72,879,000	72,965,000	72,864,000
Dilutive effect of stock-based awards	595,000	566,000	565,000	550,000
Shares used in computing diluted earnings per share	73,216,000	73,445,000	73,530,000	73,414,000
Basic earnings per share	$ 0.29	$ 0.34	$ 0.89	$ 1.06
Diluted earnings per share	$ 0.29	$ 0.34	$ 0.88	$ 1.05
Number of antidilutive options that were excluded from computation of earnings per share	0	0	0	0