Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019	Jan. 01, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 5,069,965	$ 2,714,883	$ 4,435,203	$ 2,042,306
Total changes in other comprehensive income	22,048	4,912	18,188	35,999
Amounts reclassified to accumulated deficit pursuant to adoption of new accounting standard					$ (40,310)	$ 9,229
Ending Balance	5,253,394	2,934,481	5,253,394	2,934,481
Foreign Currency Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			(11,227)	(21,031)
Other comprehensive income before reclassifications			10,263	6,800
Amounts reclassified from accumulated other comprehensive income (loss)			0	0
Total changes in other comprehensive income			10,263	6,800
Amounts reclassified to accumulated deficit pursuant to adoption of new accounting standard		949		949
Ending Balance	(964)	(13,282)	(964)	(13,282)
On Available-For-Sale Debt Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			(536)	(594)
Other comprehensive income before reclassifications			1,111	137
Amounts reclassified from accumulated other comprehensive income (loss)			0	0
Total changes in other comprehensive income			1,111	137
Amounts reclassified to accumulated deficit pursuant to adoption of new accounting standard		0		0
Ending Balance	575	(457)	575	(457)
On Equity Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance				25,069
Other comprehensive income before reclassifications				0
Amounts reclassified from accumulated other comprehensive income (loss)				0
Total changes in other comprehensive income				0
Amounts reclassified to accumulated deficit pursuant to adoption of new accounting standard		(25,069)		(25,069)
Ending Balance		0		0
On Foreign Currency Forward Contracts
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			12,422	(15,016)
Other comprehensive income before reclassifications			26,663	21,102
Amounts reclassified from accumulated other comprehensive income (loss)			(19,849)	7,960
Total changes in other comprehensive income			6,814	29,062
Amounts reclassified to accumulated deficit pursuant to adoption of new accounting standard		0		0
Ending Balance	19,236	14,046	19,236	14,046
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(3,201)	(4,605)	659	(11,572)
Other comprehensive income before reclassifications			38,037	28,039
Amounts reclassified from accumulated other comprehensive income (loss)			(19,849)	7,960
Total changes in other comprehensive income	22,048	4,912	18,188	35,999
Amounts reclassified to accumulated deficit pursuant to adoption of new accounting standard		(24,120)		(24,120)		$ (24,120)
Ending Balance	$ 18,847	$ 307	$ 18,847	$ 307