Condensed Consolidated Statements of Comprehensive Income (Unuaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 55,925	$ 47,532	$ 188,087	$ 156,495
Other comprehensive (loss) income:
Change in foreign currency translation adjustment	0	(12,890)	0	(15,617)
Available for sale securities:
Change in net unrealized gains (losses)	94	(911)	1,392	(182)
Less: reclassification adjustment for net gains included in net income	232	(96)	164	(961)
Net change (net of tax effect)	326	(1,007)	1,556	(1,143)
Loss on pension liability	0	(45)	0	(45)
Cash flow hedges:
Change in unrealized losses	(2,348)	(6,809)	(5,692)	(4,197)
Less: reclassification adjustment for net losses (gains) included in net income	1,794	(1,500)	11,462	(4,448)
Net change (net of tax effect)	(554)	(8,309)	5,770	(8,645)
Other comprehensive (loss) income	(228)	(22,251)	7,326	(25,450)
Comprehensive income	$ 55,697	$ 25,281	$ 195,413	$ 131,045