Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Leases
Operating lease cost	$ 10,620	$ 21,414
Short-term lease cost	838	1,629
Variable lease cost	2,096	4,742
Total lease costs	13,554	27,785
Sublease income	(2,418)	(4,757)
Total lease costs, net of sublease income	$ 11,136	$ 23,028