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Servicing - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018
Transfers And Servicing [Abstract] |  |
Loans serviced for others unpaid principal amount | $ 303.9 | $ 289.2
Capitalized service right assets included in other assets | 2.6 | 2.4
Fair market value of the capitalized servicing rights | $ 2.9 | $ 3.3
Prepayment rate | 14.10% | 8.90%
Discount yield | 5.42% | 6.60%

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