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Loans - Troubled Debt Restructurings (Detail) - USD ($) $ in Thousands | 9 Months Ended
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Sep. 30, 2020 | Sep. 30, 2019
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Balance at time of restructuring | $ 12,562 | $ 13,425
Balance at period end | 9,285 | 11,805
Commercial Portfolio Segment [Member] |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Balance at time of restructuring | 3,660 | 3,845
Balance at period end | 1,415 | 2,188
Commercial real estate, Buildings, land and other [Member] |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Balance at time of restructuring | 6,606 | 9,456
Balance at period end | 6,585 | 9,494
Construction Loans [Member] |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Balance at time of restructuring | 1,192 | 0
Balance at period end | 1,181 | 0
Total consumer real estate loans [Member] |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Balance at time of restructuring | 0 | 124
Balance at period end | 0 | 123
Consumer Loan [Member] |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |
Balance at time of restructuring | 1,104 | 0
Balance at period end | $ 104 | $ 0

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- Definition 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 + Details
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