Consolidated Statements of Stockholders Equity (USD $) In Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance at Dec. 31, 2010	$ 625,945	$ 112	$ 421,991	$ 387,163	$ (175,220)	$ (8,101)
Net income	147,335			147,335
Other comprehensive income from currency exchange, net of tax	(5,615)					(5,615)
Total comprehensive income	141,720
Repurchase of common stock	(443)				(443)
Issuance of common stock	44,214	2	44,212
Ending Balance at Dec. 31, 2011	811,436	114	466,203	534,498	(175,663)	(13,716)
Net income	216,199			216,199
Other comprehensive income from currency exchange, net of tax	10,370					10,370
Total comprehensive income	226,569
Repurchase of common stock	(200,000)				(200,000)
Issuance of common stock	75,817	2	75,815
Ending Balance at Dec. 31, 2012	913,822	116	542,018	750,697	(375,663)	(3,346)
Net income	284,501			284,501
Other comprehensive income from currency exchange, net of tax	(44,080)					(44,080)
Total comprehensive income	240,421
Issuance of common stock	89,650	1	89,649
Ending Balance at Dec. 31, 2013	$ 1,243,893	$ 117	$ 631,667	$ 1,035,198	$ (375,663)	$ (47,426)