| Deposits - Additional Information (Detail) - USD ($) $ in Millions | Sep. 30, 2023 | Dec. 31, 2022 | 
|---|---|---|
| Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] | ||
| Accrued interest payable on deposits | $ 50.3 | $ 7.8 | 
| Total deposits reclassified to loans due to overdrafts | $ 1.3 | $ 1.2 | 
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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. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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- Definition Amount of accrued but unpaid interest on deposit liabilities. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Amount of deposits held by the entity that have been reclassified as loan balances receivable, for example, but not limited to, overdrafts receivable. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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