Adoption of ASU No. 2016-02, Leases (Lease Costs) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 668	$ 2,343
Variable lease cost	210	1,059
Short-term lease cost	422	4,072
Total lease cost	1,300	7,474
Lease operating expense
Lessee, Lease, Description [Line Items]
Total lease cost	378	4,016
General and administrative
Lessee, Lease, Description [Line Items]
Total lease cost	$ 922	$ 3,458