Leases - Leases, Liability, Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2019 (excluding the nine months ended September 30, 2019)	$ 891
2020	3,140
2021	3,094
2022	3,091
2023	3,041
Thereafter	11,202
Total future minimum lease payments	24,459
Less imputed interest	(5,338)
Total	$ 19,121	$ 20,800