Leases - Lease Costs and Other Quantitative Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Leases [Abstract]
Operating lease cost	$ 17,473	$ 15,981	$ 33,914	$ 34
Variable lease cost	4,361		9,325
Sublease rental income	(2,590)	$ (926)	(4,189)	$ (2)
Total lease cost	19,244		39,050
Operating cash flows	19,523		35,175
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 2,195		$ 259,013
Weighted average discount rate - Operating leases	863.00%		863.00%