Loans and Allowance For Loan Losses - Summary of Aging Analysis of the Loan Portfolio by the Time Past Due (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Total	$ 968,945	$ 949,652
Commercial And Industrial [Member]
Financing Receivable, Past Due [Line Items]
Total	416,308	389,746
Real Estate Construction And Land [Member]
Financing Receivable, Past Due [Line Items]
Total	41,697	42,519
Real Estate HELOC [Member]
Financing Receivable, Past Due [Line Items]
Total	995	982
Installment And Other [Member]
Financing Receivable, Past Due [Line Items]
Total	13,180	13,476
Loans Receivable [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	2,650	2,753
Current	966,295	945,459
Total	968,945	949,652
Loans Receivable [Member] | Over 60 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due		1,440
Loans Receivable [Member] | Commercial And Industrial [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	2,306	2,409
Current	414,002	385,897
Total	416,308	389,746
Loans Receivable [Member] | Commercial And Industrial [Member] | Over 60 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due		1,440
Loans Receivable [Member] | Real Estate Construction And Land [Member]
Financing Receivable, Past Due [Line Items]
Current	41,697	42,519
Total	41,697	42,519
Loans Receivable [Member] | Real Estate, Other [Member]
Financing Receivable, Past Due [Line Items]
Current	496,765	502,929
Total	496,765	502,929
Loans Receivable [Member] | Real Estate HELOC [Member]
Financing Receivable, Past Due [Line Items]
Current	995	982
Total	995	982
Loans Receivable [Member] | Installment And Other [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	344	344
Current	12,836	13,132
Total	$ 13,180	$ 13,476