Fair Value Measurement - Estimated Fair Values of Financial Instruments that are Reported at Amortized Cost in Consolidated Balance Sheets (Detail) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Financial assets:
Cash and due from banks	$ 57,032,000	$ 77,253,000
Cash at Federal Reserve and other banks	711,389,000	592,298,000
Securities held to maturity	199,759,000	284,563,000
Restricted equity securities	0	0
Financial liabilities:
Other borrowings	50,087,000	26,914,000
Junior subordinated debt	58,079,000	57,635,000
Level 3 | Overdraft privilege commitments (1)
Off-balance sheet:
Contract amount, Off-balance sheet	125,670,000	110,813,000
Level 3 | Standby letters of credit (1)
Off-balance sheet:
Contract amount, Off-balance sheet	21,871,000	15,056,000
Level 3 | Commitments (1)
Off-balance sheet:
Contract amount, Off-balance sheet	1,586,068,000	1,426,827,000
Fair Value | Level 1
Financial assets:
Cash and due from banks	57,032,000	77,253,000
Cash at Federal Reserve and other banks	711,389,000	592,298,000
Fair Value | Level 2
Financial assets:
Securities held to maturity	208,140,000	298,726,000
Financial liabilities:
Deposits	7,366,422,000	6,507,235,000
Other borrowings	50,087,000	26,914,000
Fair Value | Level 3
Financial assets:
Loans, net	4,880,044,000	4,753,027,000
Financial liabilities:
Junior subordinated debt	57,173,000	56,632,000
Fair Value | Level 3 | Overdraft privilege commitments (1)
Off-balance sheet:
Fair value, Off-balance sheet	1,257,000	1,108,000
Fair Value | Level 3 | Standby letters of credit (1)
Off-balance sheet:
Fair value, Off-balance sheet	219,000	151,000
Fair Value | Level 3 | Commitments (1)
Off-balance sheet:
Fair value, Off-balance sheet	15,861,000	14,268,000
Carrying Amount | Level 1
Financial assets:
Cash and due from banks	57,032,000	77,253,000
Cash at Federal Reserve and other banks	711,389,000	592,298,000
Carrying Amount | Level 2
Financial assets:
Securities held to maturity	199,759,000	284,563,000
Restricted equity securities	17,250,000	17,250,000
Financial liabilities:
Deposits	7,367,159,000	6,505,934,000
Other borrowings	50,087,000	26,914,000
Carrying Amount | Level 3
Financial assets:
Loans, net	4,831,248,000	4,671,280,000
Financial liabilities:
Junior subordinated debt	$ 58,079,000	$ 57,635,000