Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Leases [Abstract]
Operating lease cost	$ 3,260	$ 6,759
Finance lease cost:
Amortization of ROU assets	2,489	4,785
Interest on lease liabilities	485	985
Other lease costs and income:
Variable lease costs	2,778	4,867
Sublease income	(932)	(1,896)
Cost of revenues
Lessee, Lease, Description [Line Items]
Lease, cost	2,932	5,632
Selling, general and administrative expenses
Lessee, Lease, Description [Line Items]
Lease, cost	4,629	8,798
Research and development expenses
Lessee, Lease, Description [Line Items]
Lease, cost	$ 34	$ 85