Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 236	$ 167
Operating lease payments	236	167
Operating lease right-of-use assets	1,388	1,370	$ 1,580
Operating lease liabilities	$ 1,388	$ 1,370
Weighted average remaining lease term	1 year 7 months 6 days	2 years 1 month 6 days
Weighted average discount rate	3.10%	3.10%
2020	$ 632
2021	695
2022	$ 61
Lessor, Operating Lease, Existence of Option to Extend [true false]	true
Property, plant and equipment, gross	$ 567,808	$ 553,609	$ 567,215
Lease income	$ 737	749
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	3 years
Commercial real estate leased to third parties
Lessee, Lease, Description [Line Items]
Property, plant and equipment, gross	$ 36,368	36,371
Depreciation	$ 10,433	$ 9,709
Commercial real estate leased to third parties | Maximum
Lessee, Lease, Description [Line Items]
Lessor, renewal term	60 years