Loan Servicing - Loan Servicing Rights - Additional Information (Details) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Loan Servicing
Carrying amount/fair value	$ 1,295,000	$ 1,651,000	$ 2,594,000
Prepayment speed assumption (annual rate) (as a percent)	13.50%	10.89%	8.13%
Residual cash flow discount rate assumption (annual) (as a percent)	15.90%	16.40%	13.86%
Loan servicing rights
Loan Servicing
Valuation allowance	$ 0	$ 0	$ 0

Discount rate which is used to value residual cash flows generated by financial assets of a securitization, asset-backed financing arrangement, or similar transfer regardless of when the transfer occurred.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=118948506&loc=d3e107314-111719

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- Definition

Estimated rate of prepayment of principal on financial assets regardless of when the transfer occurred.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=118948506&loc=d3e107314-111719

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- Definition

The carrying amount (fair value) as of the balance sheet date of the transferor's interests in transferred financial assets (typically securitized receivables, generally not involved in the collection of principal) following transfer of significant portions of such financial instruments to other parties. Such interests could be ancillary cash flows and interest-only strips.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=118948506&loc=d3e107314-111719

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- Definition

Amount of increase (decrease) in the amortized amount from a decrease (increase) in the valuation allowance applied to the servicing asset for a contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 4
-Subparagraph (a)(5)
-URI http://asc.fasb.org/extlink&oid=116651436&loc=d3e122739-111746

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Balance Type:	debit
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- References

No definition available.

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