| Fair Value Measurements - Quantitative Information about Level 3 Fair Value Comments for Assets Measured at Fair Value on Non-Recurring Basis (Parenthetical) (Detail) | Mar. 31, 2020  SecurityLoan | 
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| Commercial term | Commercial and Industrial | Fair Value, Inputs, Level 3 | Non-recurring Basis | |
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | |
| Number of loans receivable | 1 | 
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
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