Leases (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) lease	Jun. 30, 2018 USD ($)
Lease cost
Operating lease cost	$ 420,000		$ 834,000
Short-term lease cost	29,000		68,000
Variable lease cost	4,000		18,000
Total lease cost	453,000		920,000
Cash paid for lease liabilities	$ 428,000		$ 734,000
Weighted average remaining lease term	3 years		3 years
Weighted average discount rate	3.30%		3.30%
Right-of-use assets	$ 3,490,000		$ 3,490,000
Right-of-use assets, line item in Statement of Financial Position	us-gaap:OtherAssetsMember		us-gaap:OtherAssetsMember
Lease liabilities	$ 3,500,000		$ 3,500,000
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	$ 227,000		$ 1,050,000
Lease expense recognized		$ 500,000		$ 939,000
Maturities of lease liabilities
2019	703,000		703,000
2020	1,479,000		1,479,000
2021	883,000		883,000
2022	270,000		270,000
2023	113,000		113,000
Thereafter	223,000		223,000
Total	3,671,000		3,671,000
Imputed interest	(173,000)		(173,000)
Lease liabilities	$ 3,498,000		3,498,000
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