Condensed Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 107,660	$ 61,053	$ 188,059	$ 119,990
Other comprehensive income (loss):
Foreign currency translation adjustments	(2,758)	(2,312)	(1,726)	(7,774)
Income tax effect	1,065	888	665	2,998
Foreign currency translation adjustments, net	(1,693)	(1,424)	(1,061)	(4,776)
Unrealized gains (losses) on cash flow hedges	0	574	0	1,167
Income tax effect	0	(221)	0	(447)
Unrealized gains (losses) on cash flow hedges, net	0	353	0	720
Unrealized gains (losses) on available-for-sale securities	0		0	(5)
Income tax effect	0		0	2
Unrealized gains (losses) on available-for-sale securities, net	0		0	(3)
Pension and other post-retirement adjustments	173	23	166	115
Income tax effect	(2)	(2)	2	(33)
Pension and other post-retirement adjustments, net	171	21	168	82
Other comprehensive income (loss), net of tax	(1,522)	(1,050)	(893)	(3,977)
Comprehensive income	$ 106,138	$ 60,003	$ 187,166	$ 116,013