Condensed 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, 2012		$ 139	$ 798,093	$ 43,779	$ 0
Balance at beginning of period, (in shares) at Dec. 31, 2012		139,439
Net issuances of restricted stock, (in shares)		959
Repurchases of common stock, (in shares)		(3,377)
Exercises of stock options, (in shares)		1,265
Net issuances of restricted stock		1	(1)
Repurchases of common stock		(3)			(118,957)
Exercise of stock options		1	29,895
Cash dividends			(12,256)		(54,718)
Stock-based compensation expense			28,559
Tax impact of equity incentive plans			3,428
Foreign currency translation adjustments, net of tax	(4,486)			(4,486)
Net income	185,310				185,310
Balance at end of period at Sep. 30, 2013		138	847,718	39,293	11,635
Balance at end of period, (in shares) at Sep. 30, 2013		138,286
Balance at beginning of period at Dec. 31, 2013	919,643	137	868,120	38,071	13,315
Balance at beginning of period, (in shares) at Dec. 31, 2013		137,466
Net issuances of restricted stock, (in shares)		796
Repurchases of common stock, (in shares)		(2,808)
Exercises of stock options, (in shares)		469
Net issuances of restricted stock		1	(1)
Repurchases of common stock		(3)			(126,828)
Exercise of stock options		1	12,686
Cash dividends			0		(73,969)
Stock-based compensation expense			29,960
Tax impact of equity incentive plans			2,213
Foreign currency translation adjustments, net of tax	(12,995)			(12,995)
Net income	221,875				221,875
Balance at end of period at Sep. 30, 2014	$ 972,583	$ 136	$ 912,978	$ 25,076	$ 34,393
Balance at end of period, (in shares) at Sep. 30, 2014		135,923