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Loans and Allowance for Loan Losses - Troubled Debt Restructurings (Details)	3 Months Ended		12 Months Ended
	Dec. 31, 2020 USD ($) loan	Mar. 31, 2019 loan	Dec. 31, 2020 USD ($) loan	Dec. 31, 2019 USD ($)
Troubled debt restructuring
Number of loan modifications not considered TDRs, in connection with CARES Act	577		577
Loan modifications not considered TDRS, in connection with CARES Act	$ 153,600,000		$ 153,600,000
Maximum
Troubled debt restructuring
Typical loan deferral period under the CARES Act			90 days
Extending amortization period
Troubled debt restructuring
Number of loans modified as a troubled debt restructuring | loan		1
Carrying value of restructured loan				$ 200,000
Specific reserve for loan losses allocated				$ 24,000
Interest Rate Below Market Reduction
Troubled debt restructuring
Number of loans modified as a troubled debt restructuring | loan	1
Carrying value of restructured loan			$ 2,600,000
Specific reserve for loan losses allocated	$ 0		$ 0
Second Deferral
Troubled debt restructuring
Number of loan modifications not considered TDRs, in connection with CARES Act | loan	18		18
Loan modifications not considered TDRS, in connection with CARES Act	$ 8,400,000		$ 8,400,000
First Deferral
Troubled debt restructuring
Number of loan modifications not considered TDRs, in connection with CARES Act | loan	21		21
Loan modifications not considered TDRS, in connection with CARES Act	$ 3,700,000		$ 3,700,000

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Financing receivable loan modifications value due to CARES Act, not considered troubled debt restructuring.

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Number of financing receivable loan modifications due to CARES Act, not considered troubled debt restructuring.

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Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953676-111524

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Amount, after troubled debt restructuring, of modified financing receivable.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953676-111524

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