Summary of Significant Accounting Policies - Significant events (Details)		1 Months Ended		6 Months Ended		12 Months Ended
	Mar. 24, 2021 loan	Dec. 31, 2020 employee	Oct. 31, 2020	Dec. 31, 2021 USD ($) loan	Dec. 31, 2020 USD ($) employee loan	Dec. 31, 2021 USD ($) loan
Financing Receivable, Impaired [Line Items]
Financing Receivable, Restructuring Term				6 months
Impairment of Federal Home Loan Bank stock				$ 0
Consecutive period of employee's average month pay received to determine benefits under the Plan				5 years
Number of years of employment to determine pension benefit				10 years
Deferment payment period			6 months
Number of loans modification request received | loan				85		85
Aggregate value of requested loans to be modified				$ 22,700,000		$ 22,700,000
Modified loans requested and performing under Cares Act				$ 22,400,000		$ 22,400,000
Percentage of performing loans				98.70%
TDR granted during period, including loans transferred out of TDR status | loan				3
TDR investment modified during period, including loans transferred out of TDR status				$ 284,000
PPP
Financing Receivable, Impaired [Line Items]
Minimum Percentage of Payroll Costs		60.00%
Maximum Eligible Number of Employees For First Draw of Loan | employee		500			500
Maximum eligible Number of Employees For Second Draw of Loan | employee		300			300
Minimum Percentage of Reduction in Gross Receipts, Financing Receivable		25.00%
Number of loan originated | loan					17	9
Value of loan					$ 1,100,000	$ 729,000
Processing fee income					$ 44,000	$ 32,000
Number of loans forgiven | loan	17