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Loans Held for Sale, at Fair Value - Additional Information (Detail) - USD ($) | 3 Months Ended |
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Mar. 31, 2021 | Dec. 31, 2020
Accounts and Financing Receivables, Held-for-Sale, Not Part of Disposal Group, after Valuation Allowance [Abstract] |  |
Maximum period of loans held for sale sold (in days) | 45 days |
Financing receivable, nonaccrual | $ 0 | $ 0

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Balance Type: | na
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Period Type: | instant

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