Leases - Components of lease expense and other information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019
Lease cost
Amortization of right-of-use assets	$ 1,441
Interest on lease liabilities	308
Operating lease cost	4,833
Variable lease cost	629
Short-term lease cost	41
Sublease income	(452)
Total lease cost	$ 6,800
Weighted-average remaining lease term (years), Operating leases		5 years 1 month 24 days
Weighted-average remaining lease term (years), Finance leases		2 years 8 months 23 days
Weighted-average discount rate, Operating leases		5.30%
Weighted-average discount rate, Finance leases		5.70%