Leases (Details)	3 Months Ended
	Mar. 31, 2019 USD ($) lease	Mar. 31, 2018 USD ($)
Lease cost
Operating lease cost	$ 414,000
Short-term lease cost	39,000
Variable lease cost	14,000
Total lease cost	467,000
Cash paid for lease liabilities	$ 306,000
Weighted average remaining lease term	3 years
Weighted average discount rate	3.30%
Right-of-use assets	$ 3,670,000
Right-of-use assets, line item in Statement of Financial Position	us-gaap:OtherAssetsMember
Lease liabilities	$ 3,680,000
Lease liabilities, line item in Statement of Financial Position	us-gaap:OtherLiabilitiesMember
Right-of-use assets obtained in exchange for lease liabilities	$ 821,000
Lease expense recognized		$ 439,000
Maturities of lease liabilities
2019	1,131,000
2020	1,392,000
2021	758,000
2022	236,000
2023	109,000
Thereafter	249,000
Total	3,875,000
Imputed interest	(193,000)
Lease liabilities	3,682,000
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