Consolidated Statements of Stockholders' Equity (USD $) In Thousands	Total	COMMON STOCK:	CAPITAL SURPLUS:	ACCUMULATED OTHER COMPREHENSIVE INCOME:	RETAINED EARNINGS:
Balance at beginning of period at Dec. 31, 2010		$ 146	$ 787,105	$ 47,120
Balance at beginning of period, (in shares) at Dec. 31, 2010		146,183
Net issuances of restricted stock, (in shares)		1,425
Repurchases of common stock, (in shares)		(6,328)
Exercises of stock options, (in shares)	806	806
Net issuances of restricted stock		1	(1)
Net income	149,922				149,922
Foreign currency translation adjustments, net of tax	(6,233)			(6,233)
Repurchases of common stock		(6)	(20,641)		(149,922)
Cash dividends			(81,024)
Stock-based compensation expense			50,906
Exercises of stock options		1	18,308
Tax impact of equity incentive plans			4,823
Balance at end of period at Dec. 31, 2011		142	759,476	40,887
Balance at end of period, (in shares) at Dec. 31, 2011		142,086
Net issuances of restricted stock, (in shares)		1,443
Repurchases of common stock, (in shares)		(6,350)
Exercises of stock options, (in shares)	2,260	2,260
Net issuances of restricted stock		1	(1)
Net income	209,942				209,942
Foreign currency translation adjustments, net of tax	2,892			2,892
Repurchases of common stock		(6)	(7,715)		(175,015)
Cash dividends			(49,971)		(34,927)
Stock-based compensation expense			41,464
Exercises of stock options		2	42,936
Tax impact of equity incentive plans			11,904
Balance at end of period at Dec. 31, 2012	842,011	139	798,093	43,779
Balance at end of period, (in shares) at Dec. 31, 2012		139,439
Net issuances of restricted stock, (in shares)		1,091
Repurchases of common stock, (in shares)		(4,461)
Exercises of stock options, (in shares)	1,397	1,397
Net issuances of restricted stock		1	(1)
Net income	252,195				252,195
Foreign currency translation adjustments, net of tax	(5,708)			(5,708)
Repurchases of common stock		(4)			(162,029)
Cash dividends			(12,256)		(76,851)
Stock-based compensation expense			38,867
Exercises of stock options		1	33,285
Tax impact of equity incentive plans			10,132
Balance at end of period at Dec. 31, 2013	$ 919,643	$ 137	$ 868,120	$ 38,071	$ 13,315
Balance at end of period, (in shares) at Dec. 31, 2013		137,466