Employee Benefit Plans (Details)	12 Months Ended
	Dec. 31, 2019 USD ($) plan employee	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Defined contribution plan [Abstract]
Defined contribution plan service period (in months)	3 months
Defined contribution plan employer maximum percentage match of annual salary based on employee contribution (in hundredths)	3.00%
Defined contribution plan employer maximum percentage of annual profit-sharing contribution to plan for benefit of employee (in hundredths)	2.00%	2.00%	2.00%
Expense related to 401(k) plan	$ 575,000	$ 578,000	$ 554,000
Defined benefit plans, general information	The Bank also provides unfunded supplemental retirement benefits for certain officers, payable in installments over 20 years commencing upon retirement or death. The agreements consist of individual contracts with differing characteristics that, when taken together, do not constitute a post-retirement plan.
Non-qualified deferred compensation payable period (in years)	2 years
Supplemental retirement benefits, period of benefits to be received	20 years
Pension expense	$ 165,000	176,000	$ 219,000
Accrued pension liability	$ 2,828,000	$ 2,949,000
Number of post-retirement benefit plans | plan	2
Number of active employees aged 50 and over | employee	6
Employee benefit plan age (in years)	50 years
Post-retirement benefit plan health insurance subsidy range minimum per month per person	$ 40
Post-retirement benefit plan health insurance subsidy range maximum per month per person	1,200
Expected future benefit payments in 2020	108,000
Expected future benefit payments in 2021	106,000
Expected future benefit payments in 2022	103,000
Expected future benefit payments in 2023	101,000
Expected future benefit payments in 2024	107,000
Expected future benefit payments in 2024 through 2028	496,000
Estimated plan expense	$ 64,000
Federal statutory income tax rate (percent)	21.00%	21.00%