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Loans and Allowance for Credit Losses - Troubled Debt Restructured Loans and Commitments (Detail) - USD ($) $ in Thousands | Sep. 30, 2021 | Dec. 31, 2020
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Financing Receivable, Troubled Debt Restructurings [Line Items] |  |
Financing Receivable, Troubled Debt Restructuring | $ 23,620 | $ 23,252
Financing Receivable, Troubled Debt Restructuring, Commitment to Lend | 75 | 71
Letter of Credit [Member] |  |
Financing Receivable, Troubled Debt Restructurings [Line Items] |  |
Financing Receivable, Troubled Debt Restructuring, Commitment to Lend | 60 | 60
Unused lines of Credit [Member] |  |
Financing Receivable, Troubled Debt Restructurings [Line Items] |  |
Financing Receivable, Troubled Debt Restructuring, Commitment to Lend | 15 | 11
Accrual Loans [Member] [Member] |  |
Financing Receivable, Troubled Debt Restructurings [Line Items] |  |
Financing Receivable, Troubled Debt Restructuring | 7,410 | 8,512
Non Accrual Loans [Member] |  |
Financing Receivable, Troubled Debt Restructurings [Line Items] |  |
Financing Receivable, Troubled Debt Restructuring | $ 16,210 | $ 14,740

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- Definition Amount of financing receivable modified as troubled debt restructuring. + 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=123577603&loc=SL6953676-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 40 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=121585226&loc=d3e18845-111554 + Details
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- Definition Amount of unfunded portion of contractual agreement to lend funds to borrower for financing receivable modified as troubled debt restructuring. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 40 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121585226&loc=d3e18794-111554 + Details
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