Fair Value Measurement - Estimated Fair Values of Financial Instruments that are Reported at Amortized Cost in Consolidated Balance Sheets (Detail) - USD ($)	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Financial assets:
Cash and due from banks	$ 73,322,000	$ 81,626,000
Cash at Federal Reserve and other banks	9,514,000	17,075,000
Equity securities, fair value	0		$ 0
Financial liabilities:
Other borrowings	392,409,000	632,582,000
Junior subordinated debt	101,120,000	101,099,000
Level 3 | Overdraft Privilege Commitments
Off-balance sheet:
Contract Amount	129,273,000	121,539,000
Level 3 | Standby letters of credit
Off-balance sheet:
Contract Amount	41,912,000	38,449,000
Level 3 | Commitments
Off-balance sheet:
Contract Amount	2,206,882,000	2,225,677,000
Carrying Amount | Level 1
Financial assets:
Cash and due from banks	73,322,000	81,626,000
Cash at Federal Reserve and other banks	9,514,000	17,075,000
Carrying Amount | Level 2
Financial assets:
Securities held to maturity	127,811,000	133,494,000
Equity securities, fair value	17,250,000	17,250,000
Financial liabilities:
Deposits	7,987,658,000	7,834,038,000
Other borrowings	392,409,000	632,582,000
Carrying Amount | Level 3
Financial assets:
Loans, net	6,676,301,000	6,672,948,000
Financial liabilities:
Junior subordinated debt	101,120,000	101,099,000
Fair Value | Level 1
Financial assets:
Cash and due from banks	73,322,000	81,626,000
Cash at Federal Reserve and other banks	9,514,000	17,075,000
Fair Value | Level 2
Financial assets:
Securities held to maturity	118,528,000	125,126,000
Financial liabilities:
Deposits	7,982,067,000	7,828,554,000
Other borrowings	329,409,000	632,582,000
Fair Value | Level 3
Financial assets:
Loans, net	6,291,078,000	6,278,577,000
Financial liabilities:
Junior subordinated debt	101,090,000	95,407,000
Fair Value | Level 3 | Overdraft Privilege Commitments
Off-balance sheet:
Fair Value	1,293,000	1,215,000
Fair Value | Level 3 | Standby letters of credit
Off-balance sheet:
Fair Value	419,000	385,000
Fair Value | Level 3 | Commitments
Off-balance sheet:
Fair Value	$ 22,069,000	$ 22,257,000