Earnings Per Share (Basic And Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Earnings Per Share [Abstract]
Net income	$ 25,840	$ 30,680	$ 43,351	$ 51,925
Weighted average common shares outstanding	73,022,000	72,859,000	73,140,000	72,857,000
Dilutive effect of stock-based awards	576,000	553,000	550,000	544,000
Shares used in computing diluted earnings per share	73,598,000	73,412,000	73,690,000	73,401,000
Basic earnings per share	$ 0.35	$ 0.42	$ 0.59	$ 0.71
Diluted earnings per share	$ 0.35	$ 0.42	$ 0.59	$ 0.71
Number of antidilutive options that were excluded from computation of earnings per share	0	0	0	0