Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Quantitative Information about Level 3 Fair Value Comments for Assets Measured at Fair Value on Non-Recurring Basis (Detail)

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Fair Value Measurements - Quantitative Information about Level 3 Fair Value Comments for Assets Measured at Fair Value on Non-Recurring Basis (Detail) - Fair Value, Inputs, Level 3 - Non-recurring Basis
$ in Thousands
Sep. 30, 2020
USD ($)
Dec. 31, 2019
USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value $ 46,106 $ 31,049
Real Estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value 44,626 27,154
Consumer    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value $ 1,192  
Alternative Investment, Valuation Technique [Extensible List] us-gaap:MarketApproachValuationTechniqueMember  
Minimum | Consumer    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range (0.013)  
Maximum | Consumer    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range 0.015  
Weighted Average | Consumer    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range 0.006  
Retail | Real Estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value $ 5,504  
Alternative Investment, Valuation Technique [Extensible List] us-gaap:MarketApproachValuationTechniqueMember  
Retail | Minimum | Real Estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range (0.030)  
Retail | Maximum | Real Estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range 0.035  
Retail | Weighted Average | Real Estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range 0.014  
Other | Real Estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value $ 7,915 $ 13,926
Alternative Investment, Valuation Technique [Extensible List] us-gaap:MarketApproachValuationTechniqueMember us-gaap:MarketApproachValuationTechniqueMember
Other | Minimum | Real Estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range (0.055)  
Other | Maximum | Real Estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range 0.034  
Other | Weighted Average | Real Estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range 0.015  
Construction | Real Estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value $ 29,444 $ 13,228
Alternative Investment, Valuation Technique [Extensible List] us-gaap:MarketApproachValuationTechniqueMember us-gaap:MarketApproachValuationTechniqueMember
Construction | Minimum | Real Estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range (0.020) (0.003)
Construction | Maximum | Real Estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range 0.043 0.043
Construction | Weighted Average | Real Estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range 0.021 0.021
Residential Property | Real Estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value $ 1,763  
Alternative Investment, Valuation Technique [Extensible List] us-gaap:MarketApproachValuationTechniqueMember  
Residential Property | Minimum | Real Estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range (0.007)  
Residential Property | Maximum | Real Estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range 0.006  
Residential Property | Weighted Average | Real Estate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range 0.003  
Commercial term | Commercial and Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value $ 288  
Alternative Investment, Valuation Technique [Extensible List] us-gaap:MarketApproachValuationTechniqueMember  
Commercial term | Minimum | Commercial and Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range (0.009)  
Commercial term | Maximum | Commercial and Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range 0.011  
Commercial term | Weighted Average | Commercial and Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range 0.001  
Bank-Owned Premises    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value $ 1,824 $ 1,900
Alternative Investment, Valuation Technique [Extensible List] us-gaap:MarketApproachValuationTechniqueMember us-gaap:MarketApproachValuationTechniqueMember
Bank-Owned Premises | Minimum    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range (0.030) (0.030)
Bank-Owned Premises | Maximum    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range 0.035 0.055
Bank-Owned Premises | Weighted Average    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range 0.002 (0.002)
Other Real Estate Owned    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value $ 1,052  
Alternative Investment, Valuation Technique [Extensible List] us-gaap:MarketApproachValuationTechniqueMember  
Other Real Estate Owned | Minimum    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range (0.053)  
Other Real Estate Owned | Maximum    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range 0.005  
Other Real Estate Owned | Weighted Average    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range (0.003)  
Commercial lines of credit | Commercial and Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fair Value   $ 3,895
Alternative Investment, Valuation Technique [Extensible List]   us-gaap:MarketApproachValuationTechniqueMember
Commercial lines of credit | Minimum | Commercial and Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range   (0.008)
Commercial lines of credit | Maximum | Commercial and Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range   0.042
Commercial lines of credit | Weighted Average | Commercial and Industrial    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Range   0.018