Accumulated Other Comprehensive Loss (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ 2,679,800
Ending Balance	2,973,683
Foreign currency
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(47,966)
Other comprehensive income (loss) before reclassifications	2,579
Net decrease (increase) in other comprehensive loss	2,579
Ending Balance	(45,387)
Change in unrealized gains on available-for-sale securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(599)
Other comprehensive income (loss) before reclassifications	127
Net decrease (increase) in other comprehensive loss	127
Ending Balance	(472)
AOCI Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(48,565)
Other comprehensive income (loss) before reclassifications	2,706
Net decrease (increase) in other comprehensive loss	2,706
Ending Balance	$ (45,859)