Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	$ 40,187	$ 18,093
Available For Sale Securities Debt Securities	6,541,391	7,068,613
Derivative Assets, Fair Value	220,913	161,496
Derivative Liabilities, Fair Value	119,529	105,083
Securities sold not yet purchased	11,700	8,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	8,520	2,873
Available For Sale Securities Debt Securities	1,132,537	1,650,017
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	31,667	15,220
Available For Sale Securities Debt Securities	5,408,854	5,418,596
U.S. Treasury [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available For Sale Securities Debt Securities	802,500	1,298,742
U.S. Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available For Sale Securities Debt Securities	159,022	159,721
Mortgage-backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available For Sale Securities Debt Securities	3,674,183	3,620,785
State and political subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available For Sale Securities Debt Securities	1,233,920	1,286,975
Corporates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available For Sale Securities Debt Securities	330,037	351,275
Fair Value Measurement, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	40,187	18,093
Available For Sale Securities Debt Securities	6,541,391	7,068,613
Equity securities with readily determinable fair values	11,292	11,228
Company-owned life insurance	73,419	69,727
Bank-owned life insurance	527,897	523,960
Derivative Assets, Fair Value	220,913	161,496
Total	7,415,099	7,853,117
Derivative Liabilities, Fair Value	119,529	105,083
Securities sold not yet purchased	11,680	8,018
Total	131,209	113,101
Fair Value Measurement, Recurring [Member] \| Collateralized loan obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available For Sale Securities Debt Securities	341,729	351,115
Fair Value Measurement, Recurring [Member] \| Trading - other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	854	18
Fair Value Measurement, Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	8,520	2,873
Available For Sale Securities Debt Securities	1,132,537	1,650,017
Equity securities with readily determinable fair values	11,292	11,228
Total	1,152,349	1,664,118
Fair Value Measurement, Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Trading - other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	854	18
Fair Value Measurement, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	31,667	15,220
Available For Sale Securities Debt Securities	5,408,854	5,418,596
Company-owned life insurance	73,419	69,727
Bank-owned life insurance	527,897	523,960
Derivative Assets, Fair Value	220,913	161,496
Total	6,262,750	6,188,999
Derivative Liabilities, Fair Value	119,529	105,083
Securities sold not yet purchased	11,680	8,018
Total	131,209	113,101
Fair Value Measurement, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Collateralized loan obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available For Sale Securities Debt Securities	341,729	351,115
Fair Value Measurement, Recurring [Member] \| U.S. Treasury [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	1,574	881
Available For Sale Securities Debt Securities	802,500	1,298,742
Fair Value Measurement, Recurring [Member] \| U.S. Treasury [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	1,574	881
Available For Sale Securities Debt Securities	802,500	1,298,742
Fair Value Measurement, Recurring [Member] \| U.S. Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	3,318
Available For Sale Securities Debt Securities	159,022	159,721
Fair Value Measurement, Recurring [Member] \| U.S. Agencies [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	3,318
Available For Sale Securities Debt Securities	159,022	159,721
Fair Value Measurement, Recurring [Member] \| Mortgage-backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		1,738
Available For Sale Securities Debt Securities	3,674,183	3,620,785
Fair Value Measurement, Recurring [Member] \| Mortgage-backed [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities		1,738
Available For Sale Securities Debt Securities	3,674,183	3,620,785
Fair Value Measurement, Recurring [Member] \| State and political subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	28,349	13,482
Available For Sale Securities Debt Securities	1,233,920	1,286,975
Fair Value Measurement, Recurring [Member] \| State and political subdivisions [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	28,349	13,482
Available For Sale Securities Debt Securities	1,233,920	1,286,975
Fair Value Measurement, Recurring [Member] \| Corporates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	6,092	1,974
Available For Sale Securities Debt Securities	330,037	351,275
Fair Value Measurement, Recurring [Member] \| Corporates [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	6,092	1,974
Available For Sale Securities Debt Securities	$ 330,037	$ 351,275

Equity securities with readily determinable fair values.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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The carrying amount of a life insurance policy on an officer, executive or employee for which the reporting entity (a bank) is entitled to proceeds from the policy upon death of the insured or surrender of the insurance policy.

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- Definition

Fair value portion of arrangements with third parties, including, but not limited to, operating lease arrangement and arrangement in which the entity has agreed to expend funds to procure goods or services, or has agreed to commit resources to supply goods or services.

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Fair value, after offset of derivative liability, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, before offset against an obligation to return collateral under a master netting arrangement. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, after offset of derivative asset, of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, elected not to be and before offset against a right to receive collateral under a master netting arrangement. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

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This item represents the amount that could be realized under a life insurance contract or contracts owned by the Entity as of the date of the statement of financial position. Such Entity-owned life insurance policies are commonly known as corporate-owned life insurance (COLI) or bank-owned life insurance (BOLI).

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Fair value of financial instruments sold short by a broker-dealer for their own account (proprietary securities) for trading or investment purposes determined by management based upon quoted prices of a financial instrument with similar characteristics or on a valuation technique or model.

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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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