Leases - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018
Lessee, Lease, Description [Line Items]
Operating lease expense	$ 200	$ 600
Finance lease expense	100	300
Short term lease costs	2,600	6,700
Cash paid for operating leases	200	600
Cash paid for finance leases	100	355	$ 0
Right-of-use assets obtained in exchange for lease obligations	$ 2,600	$ 3,200
Operating lease, weighted average lease term	2 years 2 months	2 years 2 months
Finance lease, weighted average lease term	1 year 7 months 1 day	1 year 7 months 1 day
Operating lease, weighted average discount rate (as a percent)	4.35%	4.35%
Finance lease, weighted average discount rate (as a percent)	6.69%	6.69%
Minimum
Lessee, Lease, Description [Line Items]
Renewal term		1 year
Maximum
Lessee, Lease, Description [Line Items]
Renewal term		3 years