Leases - Maturities of lease liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019
Operating Leases
2019	$ 1,324
2020	5,336
2021	5,255
2022	5,309
2023	5,292
2024	5,302
Thereafter	11,269
Total lease payments	39,087
Less: Interest	(10,940)
Present value of lease liabilities	28,147
Finance Leases
2019	0
2020	41
2021	41
2022	41
2023	41
2024	0
Thereafter	0
Total lease payments	164
Less: Interest	(15)
Present value of lease liabilities	149
2019	1,324
2020	5,377
2021	5,296
2022	5,350
2023	5,333
2024	5,302
Thereafter	11,269
Total lease payments	39,251
Less: Interest	(10,955)
Present value of lease liabilities	$ 28,296	$ 27,800