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Loans and Allowance for Credit Losses - Troubled Debt Restructuring Modifications (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) contract	Dec. 31, 2019 USD ($) contract	Dec. 31, 2018 USD ($) contract
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts Modified | contract	5
Pre-Modification Amortized Cost	$ 2,203
Post-Modification Amortized Cost	2,195
Post-Modification Amortized Cost at Period End	$ 2,121
Commercial | Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts Modified | contract	1	1	2
Pre-Modification Amortized Cost	$ 170	$ 298	$ 254
Post-Modification Amortized Cost	162	298	245
Post-Modification Amortized Cost at Period End	$ 96	$ 150	$ 172
Commercial real estate | Commercial real estate, investor-owned
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts Modified | contract	1
Pre-Modification Amortized Cost	$ 1,553
Post-Modification Amortized Cost	1,553
Post-Modification Amortized Cost at Period End	$ 1,553
Residential loans | Home equity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts Modified | contract	1
Pre-Modification Amortized Cost	$ 276
Post-Modification Amortized Cost	276
Post-Modification Amortized Cost at Period End	$ 271
Consumer loans | Installment and other consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts Modified | contract	2
Pre-Modification Amortized Cost	$ 204
Post-Modification Amortized Cost	204
Post-Modification Amortized Cost at Period End	$ 201

X

- Definition

The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings at end of period.

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- Definition

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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- Definition

Amount, before troubled debt restructuring, of financing receivable to be modified.

+ 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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