Consolidated Statements Of Stockholders' Equity (USD $) In Thousands	Common Stock [Member]	Capital Surplus [Member]	Accumulated Other Comprehensive Income [Member]	Retained Earnings [Member]	Comprehensive Income [Member]	Total
Balance at beginning of period, value at Dec. 31, 2008	$ 151	$ 949,474	$ 34,263
Balance at beginning of period, shares at Dec. 31, 2008	150,943
Net issuances of restricted stock, shares	2,400
Net issuances of restricted stock, value	2	(2)
Repurchases of common stock, shares	(6,398)
Repurchases of common stock, value	(6)	(112,549)		(37,263)
Cash dividends		(72,459)
Stock-based compensation expense		61,148
Exercises of stock options, shares	1,700
Exercises of stock options, value	2	24,949
Translation adjustments			11,317		11,317
Tax impact of equity incentive plans		3,520
Net income				37,263	37,263	37,263
Total comprehensive income					48,580
Balance at end of period, value at Dec. 31, 2009	149	854,081	45,580
Balance at end of period, shares at Dec. 31, 2009	148,645
Net issuances of restricted stock, shares	1,574
Net issuances of restricted stock, value	1	(1)
Repurchases of common stock, shares	(5,762)
Repurchases of common stock, value	(6)	(103,153)		(52,301)
Cash dividends		(63,147)		(13,768)
Stock-based compensation expense		57,119
Exercises of stock options, shares	1,726
Exercises of stock options, value	2	38,353
Translation adjustments			1,540		1,540
Tax impact of equity incentive plans		3,853
Net income				66,069	66,069	66,069
Total comprehensive income					67,609
Balance at end of period, value at Dec. 31, 2010	146	787,105	47,120			834,371
Balance at end of period, shares at Dec. 31, 2010	146,183
Net issuances of restricted stock, shares	1,425
Net issuances of restricted stock, value	1	(1)
Repurchases of common stock, shares	(6,328)
Repurchases of common stock, value	(6)	(20,641)		(149,922)
Cash dividends		(81,024)
Stock-based compensation expense		50,906
Exercises of stock options, shares	806
Exercises of stock options, value	1	18,308
Translation adjustments			(6,233)		(6,233)
Tax impact of equity incentive plans		4,823
Net income				149,922	149,922	149,922
Total comprehensive income					143,689
Balance at end of period, value at Dec. 31, 2011	$ 142	$ 759,476	$ 40,887			$ 800,505
Balance at end of period, shares at Dec. 31, 2011	142,086