Loans and Allowance for Credit Losses - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non Accrual Status Of Loans After Number Of Days Past Due			90 days
Default Status Of TDRs After Number Of Days Past Due			90 days
Charge-offs	$ 9,343,000	$ 2,106,000	$ 11,226,000	$ 3,729,000
Unfunded commitments related to nonperforming loans	200,000		200,000		$ 200,000
Off balance sheet reserve to nonperforming loans	0		0		0
Total gains or losses included in earnings	0	0	0	0
Recorded investment	48,009,000		48,009,000		35,487,000
Loans with modifications to rate and payment due to reamortization				10,000
Loans and Leases Receivable, Gross	8,799,836,000		8,799,836,000		7,642,143,000
Loans and Leases Receivable, Net of Deferred Income	8,799,836,000		$ 8,799,836,000		7,642,143,000
Forecasted Value, National Unemployment, Percent			3.52%
Financing Receivable, before Allowance for Credit Loss	8,799,836,000		$ 8,799,836,000		7,642,143,000
Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery			9,800,000	2,700,000
Accrual Loans [Member] [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring					6,400,000
Centric Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest	18,700,000		18,700,000
Net Deferred Fees
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Deferred Income	7,400,000		7,400,000		5,900,000
Unearned Premiums and Discounts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Deferred Income	(30,100,000)		(30,100,000)		(5,400,000)
Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	13,168,000		$ 13,168,000		15,896,000
Weighted average [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forecasted Value, National Unemployment, Percent			4.47%
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forecasted Value, National Unemployment, Percent			4.83%
Time and Demand Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs			$ 6,470,000
Loans and Leases Receivable, Gross	1,229,231,000		1,229,231,000		1,023,824,000
Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs			0
Loans and Leases Receivable, Gross	515,875,000		515,875,000		431,151,000
Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs	6,677,000	509,000	7,340,000	984,000
Loans and Leases Receivable, Gross	1,501,994,000		1,501,994,000		1,211,706,000
Loans and Leases Receivable, Net of Deferred Income	1,501,994,000		1,501,994,000		1,211,706,000
Financing Receivable, before Allowance for Credit Loss	1,501,994,000		1,501,994,000		1,211,706,000
Commercial, financial, agricultural and other [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,680,000		1,680,000		1,233,000
Commercial, financial, agricultural and other [Member] | Time and Demand Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs	6,215,000	139,000	6,470,000	283,000
Loans and Leases Receivable, Gross	1,229,231,000		1,229,231,000		1,023,824,000
Loans and Leases Receivable, Net of Deferred Income	1,229,231,000		1,229,231,000		1,023,824,000
Loans And Leases Receivable, Paycheck Protection Program	2,900,000		2,900,000		4,300,000
Financing Receivable, before Allowance for Credit Loss	1,229,231,000		1,229,231,000		1,023,824,000
Commercial, financial, agricultural and other [Member] | Time and Demand Loans | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,452,000		1,452,000		1,121,000
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs	1,517,000	552,000	1,517,000	552,000
Loans and Leases Receivable, Gross	3,004,962,000		3,004,962,000		2,425,012,000
Loans and Leases Receivable, Net of Deferred Income	3,004,962,000		3,004,962,000		2,425,012,000
Financing Receivable, before Allowance for Credit Loss	3,004,962,000		3,004,962,000		2,425,012,000
Commercial Real Estate [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,525,000		4,525,000		7,870,000
Commercial Real Estate [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs	0	$ 411,000	0	411,000
Loans and Leases Receivable, Gross	515,875,000		515,875,000		431,151,000
Loans and Leases Receivable, Net of Deferred Income	515,875,000		515,875,000		431,151,000
Financing Receivable, before Allowance for Credit Loss	515,875,000		515,875,000		431,151,000
Commercial Real Estate [Member] | Multifamily | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	0		$ 0		202,000
Loans to individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non Accrual Status Of Loans After Number Of Days Past Due			150 days
Nonaccrual Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Held for sale, Amount	$ 0		$ 0		$ 0
Loans and Leases Receivable, Gain (Loss) on Sales, Net			$ 0	$ 0