Commitments and Contingencies - Maturities of Lease Liabilities and Minimum Lease Payments (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Operating Leases
2019	$ 1,304
2020	1,760
2021	1,538
2022	1,410
2023	1,319
Thereafter	10,764
Total lease payments	18,095
Less imputed interest	(3,983)
Total operating lease liabilities	14,112
2019	3,032	$ 1,771
2020	2,482	1,709
2021	1,809	1,485
2022	1,013	1,355
2023	534	1,261
Thereafter	828	10,538
Total		$ 18,119
Finance Leases
2019	1,139
2020	1,216
2021	1,217
2022	1,217
2023	1,735
Thereafter	3,217
Total lease payments	9,741
Less imputed interest	(3,092)
Total	$ 6,649