Leases (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) lease	Sep. 30, 2018 USD ($)
Lease cost
Operating lease cost	$ 422,000		$ 1,256,000
Short-term lease cost	30,000		98,000
Variable lease cost	19,000		37,000
Total lease cost	471,000		1,391,000
Cash paid for lease liabilities	$ 427,000		$ 1,160,000
Weighted average remaining lease term	3 years		3 years
Weighted average discount rate	3.30%		3.30%
Right-of-use assets	$ 3,170,000		$ 3,170,000
Right-of-use assets, line item in Statement of Financial Position	us-gaap:OtherAssetsMember		us-gaap:OtherAssetsMember
Lease liabilities	$ 3,170,000		$ 3,170,000
Lease liabilities, line item in Statement of Financial Position	us-gaap:OtherLiabilitiesMember		us-gaap:OtherLiabilitiesMember
Right-of-use assets obtained in exchange for lease liabilities	$ 72,000		$ 1,120,000
Lease expense recognized		$ 344,000		$ 1,280,000
Maturities of lease liabilities
2019	282,000		282,000
2020	1,497,000		1,497,000
2021	902,000		902,000
2022	288,000		288,000
2023	126,000		126,000
Thereafter	225,000		225,000
Total	3,320,000		3,320,000
Imputed interest	(149,000)		(149,000)
Lease liabilities	$ 3,171,000		3,171,000
Payments related to lease agreements that the Corporation has not obtained control of the real estate properties			$ 4,940,000
Number of lease agreements that the Corporation has not obtained control of the real estate properties | lease			2