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, 2011		$ 142	$ 759,476	$ 40,887	$ 0
Balance at beginning 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)
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
Foreign currency translation adjustments, net of tax	2,892			2,892
Net income	209,942				209,942
Balance at end of period at Dec. 31, 2012		139	798,093	43,779	0
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)
Repurchases of common stock		(4)	0		(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
Foreign currency translation adjustments, net of tax	(5,708)			(5,708)
Net income	252,195				252,195
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
Net issuances of restricted stock, (in shares)		938
Repurchases of common stock, (in shares)		(3,798)
Exercises of stock options, (in shares)	528	528
Net issuances of restricted stock		1	(1)
Repurchases of common stock		(4)	0		(183,969)
Cash dividends			0		(98,438)
Stock-based compensation expense			40,821
Exercises of stock options		1	14,323
Tax impact of equity incentive plans			4,894
Foreign currency translation adjustments, net of tax	(23,341)			(23,341)
Net income	305,928				305,928
Balance at end of period at Dec. 31, 2014	$ 979,858	$ 135	$ 928,157	$ 14,730	$ 36,836
Balance at end of period, (in shares) at Dec. 31, 2014		135,134