Leases - Lease Cost and Other Lease Information (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Lease Costs
Operating lease costs	$ 635		$ 584	$ 1,255	$ 1,117
Variable lease costs	131		119	302	230
Short-term lease costs	15		8	30	23
Net lease cost	781	$ 800	711	1,587	1,370
Cash paid for amounts included in the measurement of lease liabilities
Operating lease cash flows - Fixed payments	612		570	1,223	1,083
Operating lease cash flows - Liability reduction	$ 534		490	1,064	953
Right of use assets obtained during the period in exchange for operating lease liabilities			$ 764	$ 128	$ 764
Weighted average lease term (in years)	6 years 5 months 8 days		6 years 9 months 21 days	6 years 5 months 8 days	6 years 9 months 21 days
Weighted average discount rate (in percent)	3.06%		3.04%	3.06%	3.04%