Fair Value Measurement - Estimates Fair Value of Financial Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financial Assets
Cash and due from banks	$ 509,669	$ 595,383
Equity securities	13,074	12,320
Available-for-sale debt securities	2,119,272	2,194,329
Net held-to-maturity debt securities	1,190,010	1,199,527
Loans held for sale	12,472	16,354
Accrued interest receivable	78,564	77,435
Financial Liabilities
Deposits	13,496,773	13,168,704
Federal Home Loan Bank borrowings	1,100,000	1,350,000
Other borrowings	72,935	105,893
Subordinated debt and junior subordinated debt	279,136	279,078
Accrued interest payable	15,929	11,121
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial Assets
Cash and due from banks	509,669	595,383
Equity securities	13,074	12,320
Accrued interest receivable	78,564	77,435
Financial Liabilities
Deposits	12,157,536	11,937,002
Other borrowings	68,622	103,057
Accrued interest payable	15,929	11,121
Significant Other Observable Inputs (Level 2) [Member]
Financial Assets
Available-for-sale debt securities	2,118,129	2,193,162
Net held-to-maturity debt securities	1,052,184	1,068,896
Loans held for sale	12,472	16,354
Other assets - interest rate derivatives	78,211	72,183
Financial Liabilities
Deposits	1,317,890	1,209,819
Federal Home Loan Bank borrowings	1,098,495	1,349,217
Subordinated debt and junior subordinated debt	230,188	240,898
Other liabilities - interest rate derivatives	78,312	73,083
Significant Unobservable Inputs (Level 3) [Member]
Financial Assets
Available-for-sale debt securities	1,143	1,167
Net held-to-maturity debt securities	260	263
Net loans	11,329,520	11,134,250
Carrying Amount [Member]
Financial Assets
Cash and due from banks	509,669	595,383
Equity securities	13,074	12,320
Available-for-sale debt securities	2,119,272	2,194,329
Net held-to-maturity debt securities	1,189,827	1,199,335
Net loans	11,743,977	11,507,786
Loans held for sale	12,472	16,354
Other assets - interest rate derivatives	78,211	72,183
Accrued interest receivable	78,564	77,435
Financial Liabilities
Deposits	13,496,773	13,168,704
Federal Home Loan Bank borrowings	1,100,000	1,350,000
Other borrowings	72,935	105,893
Subordinated debt and junior subordinated debt	279,136	279,078
Other liabilities - interest rate derivatives	78,312	73,083
Accrued interest payable	15,929	11,121
Fair Value Estimate [Member]
Financial Assets
Cash and due from banks	509,669	595,383
Equity securities	13,074	12,320
Available-for-sale debt securities	2,119,272	2,194,329
Net held-to-maturity debt securities	1,052,444	1,069,159
Net loans	11,329,520	11,134,250
Loans held for sale	12,472	16,354
Other assets - interest rate derivatives	78,211	72,183
Accrued interest receivable	78,564	77,435
Financial Liabilities
Deposits	13,475,426	13,146,821
Federal Home Loan Bank borrowings	1,098,495	1,349,217
Other borrowings	68,622	103,057
Subordinated debt and junior subordinated debt	230,188	240,898
Other liabilities - interest rate derivatives	78,312	73,083
Accrued interest payable	$ 15,929	$ 11,121