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Disclosures of Fair Values of Financial Instruments - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Carrying amount of loans with a specific allowance	$ 23,601,000	$ 25,861,000
Fair value of loans with a specific allowance	21,598,000	23,440,000
Allowance for Credit Losses	1,931,000	1,098,000
Other real estate owned	2,489,000	3,644,000
Mortgage servicing rights (MSR) impairment (recovery)	581,000	245,000
Mortgage Servicing Rights
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Finite-lived intangible assets, net	516,000	1,444,000	$ 2,101,000
Mortgage servicing rights (MSR) impairment (recovery)	273,000	380,000
Fair Value, Nonrecurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Carrying amount of loans with a specific allowance	16,789,000	13,775,000
Fair value of loans with a specific allowance	14,876,000	12,727,000
Allowance for Credit Losses	1,913,000	1,047,600
Fair Value, Nonrecurring | Mortgage Servicing Rights
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Indefinite-lived contractual rights	1,098,000	1,690,000
Finite-lived intangible assets, net	516,000	1,444,000
Fair Value, Nonrecurring | Carrying Amount
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other real estate owned	2,489,000	3,644,000
Fair Value, Nonrecurring | Fair Value
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other real estate owned	$ 290,000	$ 935,000

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 926
-SubTopic 20
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Amount of allowance for credit losses related to recorded investment.

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Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

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Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses.

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Carrying amount (original costs adjusted for previously recognized amortization and impairment) as of the balance sheet date of rights with an indefinite period of benefit that arose from a contractual arrangement with a third party (not including franchise rights and license agreements).

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The adjustment to the carrying value of the rights retained or purchased to service mortgages. These adjustments are made when the estimate of the fair value is changed. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
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Carrying amount as of the balance sheet date of land and buildings obtained through foreclosure proceedings or defeasance in full or partial satisfaction of a debt arrangement.

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