Loans and Allowance For Credit Losses - Summary of Loan Portfolio Allocated by Management's Internal Risk Ratings (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	$ 1,301,972	$ 1,369,070
Commercial And Industrial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	428,169	414,548
Real Estate Construction And Land [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	41,312	37,193
SBA [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	107,096	317,564
Other Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	61,193	49,075
Loans Receivable [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	1,301,972	1,369,070
Loans Receivable [Member] | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	1,270,682	1,340,677
Loans Receivable [Member] | Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	17,882	13,655
Loans Receivable [Member] | Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	13,408	14,738
Loans Receivable [Member] | Commercial And Industrial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	428,169	414,548
Loans Receivable [Member] | Commercial And Industrial [Member] | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	413,292	401,629
Loans Receivable [Member] | Commercial And Industrial [Member] | Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	10,933	9,013
Loans Receivable [Member] | Commercial And Industrial [Member] | Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	3,944	3,906
Loans Receivable [Member] | Real Estate, Other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	664,202	550,690
Loans Receivable [Member] | Real Estate, Other [Member] | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	653,813	540,153
Loans Receivable [Member] | Real Estate, Other [Member] | Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	4,661	2,911
Loans Receivable [Member] | Real Estate, Other [Member] | Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	5,728	7,626
Loans Receivable [Member] | Real Estate Construction And Land [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	41,312	37,193
Loans Receivable [Member] | Real Estate Construction And Land [Member] | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	37,220	34,543
Loans Receivable [Member] | Real Estate Construction And Land [Member] | Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	1,288	872
Loans Receivable [Member] | Real Estate Construction And Land [Member] | Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	2,804	1,778
Loans Receivable [Member] | SBA [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	107,096	317,564
Loans Receivable [Member] | SBA [Member] | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	105,164	315,277
Loans Receivable [Member] | SBA [Member] | Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	1,000	859
Loans Receivable [Member] | SBA [Member] | Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	932	1,428
Loans Receivable [Member] | Other Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	61,193	49,075
Loans Receivable [Member] | Other Loans [Member] | Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Credit Exposure	$ 61,193	$ 49,075