Leases - Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Leases
Election to use package of lease practical expedients			true
Term of lease	10 years		10 years
Lease costs:
Operating lease costs	$ 816	$ 782	$ 1,631	$ 1,565
Short-term lease costs	6	10	12	16
Variable lease costs	36	28	77	53
Total lease costs	858	820	1,720	1,634
Cash paid for amounts included in measurement of lease liabilities	804	772	1,606	1,545
Establishment of right-of-use asset	18	$ 13	1,786	$ 13,008
Rental expense, minimum rentals	$ 13,585		$ 13,585