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 (Loss) Income [Member]
Beginning 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 (loss) 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 (loss) 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)
Net income	368,707			368,707
Other comprehensive income (loss) from currency exchange, net of tax	(109,507)					(109,507)
Total comprehensive income	259,200
Issuance of treasury stock	1,125,964		1,096,698		29,266
Issuance of common stock	124,080	3	124,077
Ending Balance at Dec. 31, 2014	$ 2,753,137	$ 120	$ 1,852,442	$ 1,403,905	$ (346,397)	$ (156,933)