Fair Value of Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Collateral dependent impaired loans categorized as Level 3	$ 12,136	$ 14,532	$ 6,188
Specific allocation for collateral dependent impaired loans	1,109	1,657	$ 766
Collateral Dependent [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Specific allocation for collateral dependent impaired loans	1,100	1,700
Level 3 [Member] | Collateral Dependent [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Collateral dependent impaired loans categorized as Level 3	$ 4,100	$ 7,700