Fair Value Measurements - Quantitative and Qualitative Information (Details) $ in Thousands	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Quantitative information about Level 3 fair value measurements
Mortgage servicing rights, fair value	$ 4,479	$ 5,935
Securities available-for-sale, at fair value	447,436	484,648
Level 3
Quantitative information about Level 3 fair value measurements
Mortgage servicing rights, fair value	4,479	5,935
Securities available-for-sale, at fair value	4,678	5,419
US States and Political Subdivisions Debt Securities [Member]
Quantitative information about Level 3 fair value measurements
Securities available-for-sale, at fair value	250,364	249,175
US States and Political Subdivisions Debt Securities [Member] \| Level 3
Quantitative information about Level 3 fair value measurements
Securities available-for-sale, at fair value	4,700	7,200
Collateralized Mortgage Obligations [Member]
Quantitative information about Level 3 fair value measurements
Securities available-for-sale, at fair value	$ 56,113	$ 57,984
Measurement Input, Discount Rate \| Mortgage Servicing Rights [Member] \| Level 3 \| Minimum [Member]
Quantitative information about Level 3 fair value measurements
Servicing Asset, Measurement Input	11.0	10.0
Measurement Input, Discount Rate \| Mortgage Servicing Rights [Member] \| Level 3 \| Maximum [Member]
Quantitative information about Level 3 fair value measurements
Servicing Asset, Measurement Input	15.0	58.8
Measurement Input, Discount Rate \| Mortgage Servicing Rights [Member] \| Level 3 \| Weighted Average [Member]
Quantitative information about Level 3 fair value measurements
Servicing Asset, Measurement Input	11.0	10.1
Measurement Input, Constant Prepayment Rate \| Mortgage Servicing Rights [Member] \| Level 3 \| Minimum [Member]
Quantitative information about Level 3 fair value measurements
Servicing Asset, Measurement Input	0.0	0.0
Measurement Input, Constant Prepayment Rate \| Mortgage Servicing Rights [Member] \| Level 3 \| Maximum [Member]
Quantitative information about Level 3 fair value measurements
Servicing Asset, Measurement Input	45.4	69.0
Measurement Input, Constant Prepayment Rate \| Mortgage Servicing Rights [Member] \| Level 3 \| Weighted Average [Member]
Quantitative information about Level 3 fair value measurements
Servicing Asset, Measurement Input	16.7	14.1
Recurring
Quantitative information about Level 3 fair value measurements
Securities available-for-sale, at fair value		$ 8,337

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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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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-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=116651436&loc=d3e122625-111746

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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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