Fair Value Measurement - Estimates Fair Value of Financial Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Financial Assets
Cash and due from banks	$ 495,082	$ 408,411
Equity securities	11,453	11,506
Available-for-sale debt securities	2,196,141	2,529,140
Net held-to-maturity debt securities	1,210,812	1,248,409
Loans held for sale	17,677	8,249
Accrued interest receivable	73,014	68,522
Financial Liabilities
Deposits	13,090,228	13,131,090
Federal Home Loan Bank borrowings	1,125,000	705,000
Other borrowings	106,693	135,069
Subordinated debt and junior subordinated debt	282,079	281,404
Accrued interest payable	11,416	4,593
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial Assets
Cash and due from banks	495,082	408,411
Equity securities	11,453	11,506
Accrued interest receivable	73,014	68,522
Financial Liabilities
Deposits	11,913,807	12,245,272
Other borrowings	100,874	122,926
Accrued interest payable	11,416	4,593
Significant Other Observable Inputs (Level 2) [Member]
Financial Assets
Available-for-sale debt securities	2,195,028	2,527,961
Net held-to-maturity debt securities	998,701	1,084,071
Loans held for sale	17,677	8,249
Other assets - interest rate swaps	97,215	75,840
Financial Liabilities
Deposits	1,145,881	897,671
Federal Home Loan Bank borrowings	1,121,779	705,094
Subordinated debt and junior subordinated debt	246,352	258,631
Other liabilities - interest rate swaps	95,567	74,683
Significant Unobservable Inputs (Level 3) [Member]
Financial Assets
Available-for-sale debt securities	1,113	1,179
Net held-to-maturity debt securities	286	319
Net loans	10,786,103	9,487,038
Carrying Amount [Member]
Financial Assets
Cash and due from banks	495,082	408,411
Equity securities	11,453	11,506
Available-for-sale debt securities	2,196,141	2,529,140
Net held-to-maturity debt securities	1,210,812	1,248,409
Net loans	11,189,258	10,584,938
Loans held for sale	17,677	8,249
Other assets - interest rate swaps	97,215	75,840
Accrued interest receivable	73,014	68,522
Financial Liabilities
Deposits	13,090,228	13,131,090
Federal Home Loan Bank borrowings	1,125,000	705,000
Other borrowings	106,693	135,069
Subordinated debt and junior subordinated debt	282,079	281,404
Other liabilities - interest rate swaps	95,567	74,683
Accrued interest payable	11,416	4,593
Fair Value Estimate [Member]
Financial Assets
Cash and due from banks	495,082	408,411
Equity securities	11,453	11,506
Available-for-sale debt securities	2,196,141	2,529,140
Net held-to-maturity debt securities	998,987	1,084,390
Net loans	10,786,103	9,487,038
Loans held for sale	17,677	8,249
Other assets - interest rate swaps	97,215	75,840
Accrued interest receivable	73,014	68,522
Financial Liabilities
Deposits	13,059,688	13,142,943
Federal Home Loan Bank borrowings	1,121,779	705,094
Other borrowings	100,874	122,926
Subordinated debt and junior subordinated debt	246,352	258,631
Other liabilities - interest rate swaps	95,567	74,683
Accrued interest payable	$ 11,416	$ 4,593