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Servicing - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019
Transfers And Servicing [Abstract] |  |
Loans serviced for others unpaid principal amount | $ 377.5 | $ 303.9
Capitalized service right assets included in other assets | 3.3 | 2.6
Fair market value of the capitalized servicing rights | $ 3.5 | $ 2.9
Prepayment rate | 24.10% | 14.10%
Discount yield | 2.38% | 5.42%

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