Fair Value of Assets and Liabilities - Valuation Technique (Details) - Level 3	Sep. 30, 2020 USD ($) item	Dec. 31, 2019 USD ($) item
Impaired loans \| Appraisal value \| Property specific adjustment
Valuation techniques and significant unobservable inputs
Impaired loans	$ 5,301,000	$ 4,816,000
Foreclosed assets \| Appraisal value \| Property specific adjustment
Valuation techniques and significant unobservable inputs
Foreclosed assets	$ 10,000	$ 8,000
Servicing rights
Valuation techniques and significant unobservable inputs
Servicing Asset, Valuation Technique [Extensible List]	us-gaap:ValuationTechniqueDiscountedCashFlowMember	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Servicing rights \| Prepayment speed assumptions
Valuation techniques and significant unobservable inputs
Servicing rights	$ 2,579,000	$ 3,845,000
Servicing rights \| Prepayment speed assumptions \| Minimum
Valuation techniques and significant unobservable inputs
Servicing Asset, Measurement Input \| item	315	123
Servicing rights \| Prepayment speed assumptions \| Maximum
Valuation techniques and significant unobservable inputs
Servicing Asset, Measurement Input	485	267
Servicing rights \| Prepayment speed assumptions \| Weighted average
Valuation techniques and significant unobservable inputs
Servicing Asset, Measurement Input	396	194
Servicing rights \| Discount rate
Valuation techniques and significant unobservable inputs
Servicing Asset, Measurement Input	0.090	0.094
Servicing rights \| Discount rate \| Weighted average
Valuation techniques and significant unobservable inputs
Servicing Asset, Measurement Input	0.090	0.094

Fair value of foreclosed assets.

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- Definition

Fair value of impaired loans.

+ References

No definition available.

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+ References

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- Definition

Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745

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-Paragraph 3
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- Definition

Value of input used to measure servicing asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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- Definition

Indicates valuation technique for measuring servicing asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
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