Fair Value Presentation - Schedule of Quantitative Information about Level 3 Fair Value Measurements for Financial Assets Measured at Fair Value on Nonreoccuring Basis (Detail) $ in Thousands	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other real estate owned, net	$ 1,580	$ 1,207
Total	$ 1,722
Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impaired Loans, net, Range of inputs	0.03
Other Real Estate Owned, net, Range of Inputs	0.06
Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impaired Loans, net, Range of inputs	0.10
Other Real Estate Owned, net, Range of Inputs	0.10
Appraisals/Discounted Cash Flows [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impaired Loans Owned Fair Value, Net	$ 142
Appraisals [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other real estate owned, net	$ 1,580