Leases - Lease Costs and Other Quantitative Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Leases [Abstract]
Operating lease cost	$ 16,605	$ 49	$ 50,519	$ 15,768
Variable lease cost	4,960		14,285
Sublease rental income	(2,376)	$ (1,233)	(6,565)	$ (3)
Total lease cost	19,189		58,239
Operating cash flows	16,988		52,163
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 8,783		$ 267,796
Weighted average remaining lease term (in years) - Operating leases	7 years 18 days		7 years 18 days
Weighted average discount rate - Operating leases	866.00%		866.00%