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Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Goodwill And Other Intangible Assets [Line Items]      
Amortization of intangible assets $ 3,500,000 $ 3,400,000 $ 4,200,000
Goodwill impairment 0 0 0
Material impairments to identifiable intangible assets 0 0 $ 0
Mortgage Servicing Rights [Member]      
Goodwill And Other Intangible Assets [Line Items]      
Aggregate fair value of servicing rights $ 9,200,000 $ 11,500,000  
Range of discount rates used for valuation of mortgage servicing rights 10.00% 10.00%