Condensed Consolidated Statements Of Stockholders' Equity (USD $) In Thousands	Common Stock [Member]	Capital Surplus [Member]	Accumulated Other Comprehensive Income [Member]	Retained Earnings [Member]	Total
Balance at beginning of period, value at Dec. 31, 2010	$ 146	$ 787,105	$ 47,120
Balance at beginning of period, shares at Dec. 31, 2010	146,183
Net issuances of restricted stock, shares	1,181
Net issuances of restricted stock, value	1	(1)
Repurchases of common stock, shares	(1,003)
Repurchases of common stock, value	(1)	(4,261)		(26,705)
Cash dividends		(20,631)
Stock-based compensation expense		12,113
Exercises of stock options, shares	424
Exercises of stock options, value	1	9,660
Foreign currency translation adjustments, net of tax			7,433		7,433
Tax impact of equity incentive plans		1,274
Net income				26,705	26,705
Balance at end of period, value at Mar. 31, 2011	147	785,259	54,553
Balance at end of period, shares at Mar. 31, 2011	146,785
Balance at beginning of period, value at Dec. 31, 2011	142	759,476	40,887		800,505
Balance at beginning of period, shares at Dec. 31, 2011	142,086
Net issuances of restricted stock, shares	709
Net issuances of restricted stock, value	1	(1)
Repurchases of common stock, shares	(1,926)
Repurchases of common stock, value	(2)	(8,058)		(48,334)
Cash dividends		(21,370)
Stock-based compensation expense		8,886
Exercises of stock options, shares	1,434
Exercises of stock options, value	1	26,082
Foreign currency translation adjustments, net of tax			4,072		4,072
Tax impact of equity incentive plans		5,564
Net income				48,334	48,334
Balance at end of period, value at Mar. 31, 2012	$ 142	$ 770,579	$ 44,959		$ 815,680
Balance at end of period, shares at Mar. 31, 2012	142,303