CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2010	$ 828,014	$ 400	$ 151,418	$ 685,513	$ (9,317)
Foreign currency translation adjustment	(9,126)				(9,126)
Net income	95,267			95,267
Comprehensive income	86,141
Options exercised and awards vested	4,195	2	4,193
Stock-based compensation	4,542		4,544
Special items-stock-based compensation	1,351		1,351
Excess tax benefits-stock options and awards	999		999
Balance at Dec. 31, 2011	925,244	402	162,505	780,780	(18,443)
Foreign currency translation adjustment	4,613				4,613
Net income	119,209			119,209
Comprehensive income	123,822
Options exercised and awards vested	10,809	3	10,806
Stock-based compensation	5,748		5,750
Excess tax benefits-stock options and awards	807		807
Balance at Dec. 31, 2012	1,066,432	405	179,868	899,989	(13,830)
Foreign currency translation adjustment	(6,340)				(6,340)
Net income	169,827			169,827
Comprehensive income	163,487
Options exercised and awards vested	10,506	3	10,503
Stock-based compensation	8,900		8,900
Excess tax benefits-stock options and awards	2,695		2,695
Treasury stock	(10,002)	(1)	(10,001)
Balance at Dec. 31, 2013	$ 1,242,018	$ 407	$ 191,965	$ 1,069,816	$ (20,170)