Loans and Allowance - Impaired Financing Receivables (Details) - USD ($)	3 Months Ended	12 Months Ended
Mar. 31, 2021	Dec. 31, 2020
Financing Receivable, Impaired [Line Items]
Recorded Investment with specific reserves	$ 27,000	$ 28,000
Unpaid Principal Balance with specific reserves	38,000	39,000
Interest Income Recognized with specific reserves	1,000	2,000
Specific Reserve with specific reserves	11,000	11,000
Average Recorded Investment	49,000	50,000
Recorded Investment with no specific reserve	4,404,000	4,876,000
Unpaid Principal Balance with no specific reserve	4,404,000	5,027,000
Interest Income Recognized with no specific reserve	288,000	199,000
Specific Reserve	10,589
Average Recorded Investment with no specific reserve	5,027,000	5,129,000
Real Estate Loan
Financing Receivable, Impaired [Line Items]
Recorded Investment with specific reserves	27,000	28,000
Unpaid Principal Balance with specific reserves	38,000	39,000
Interest Income Recognized with specific reserves	1,000	2,000
Specific Reserve with specific reserves	11,000	11,000
Average Recorded Investment	49,000	50,000
Recorded Investment with no specific reserve	4,265,000	4,664,000
Unpaid Principal Balance with no specific reserve	4,265,000	4,815,000
Interest Income Recognized with no specific reserve	286,000	185,000
Average Recorded Investment with no specific reserve	4,877,000	4,859,000
Consumer Loan [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment with no specific reserve	139,000	212,000
Unpaid Principal Balance with no specific reserve	139,000	212,000
Interest Income Recognized with no specific reserve	2,000	14,000
Average Recorded Investment with no specific reserve	149,000	270,000
Single-family residential \| Real Estate Loan
Financing Receivable, Impaired [Line Items]
Recorded Investment with specific reserves	27,000	28,000
Unpaid Principal Balance with specific reserves	38,000	39,000
Interest Income Recognized with specific reserves	1,000	2,000
Specific Reserve with specific reserves	11,000	11,000
Average Recorded Investment	49,000	50,000
Recorded Investment with no specific reserve	99,000	171,000
Unpaid Principal Balance with no specific reserve	99,000	322,000
Average Recorded Investment with no specific reserve	100,000	544,000
Commercial \| Real Estate Loan
Financing Receivable, Impaired [Line Items]
Recorded Investment with no specific reserve	4,166,000	4,493,000
Unpaid Principal Balance with no specific reserve	4,166,000	4,493,000
Interest Income Recognized with no specific reserve	286,000	185,000
Average Recorded Investment with no specific reserve	4,777,000	4,315,000
Consumer \| Consumer Loan [Member]
Financing Receivable, Impaired [Line Items]
Specific Reserve with specific reserves		11,000
Recorded Investment with no specific reserve		34,000
Unpaid Principal Balance with no specific reserve		34,000
Interest Income Recognized with no specific reserve		4,000
Average Recorded Investment with no specific reserve		43,000
Automobile \| Consumer Loan [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment with no specific reserve	139,000	178,000
Unpaid Principal Balance with no specific reserve	139,000	178,000
Interest Income Recognized with no specific reserve	2,000	10,000
Average Recorded Investment with no specific reserve	$ 149,000	$ 227,000

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524

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Amount of allowance for credit losses related to recorded investment.

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Amount of average investment of impaired financing receivables for which there is no related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

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Amount of interest income, recognized on cash basis, on financing receivables, for which there is no related allowance for credit losses and are recognized as impaired.

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Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
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-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953550-111524

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Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses.

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

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-Publisher FASB
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-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524

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