Fair Value Measurements - Estimated Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 9,301,774	$ 12,028,132	$ 14,457,083	$ 16,583,000
Securities held to maturity, net of allowance for credit losses of $262 at March 31, 2023 and $158 at December 31, 2022	3,711,579	2,639,083
Loans, net	17,254,506	16,927,348
Deposits	42,184,155	43,954,196
Federal funds purchased	57,450	51,650
Repurchase agreements	4,237,444	4,660,641
Junior subordinated deferrable interest debentures	123,083	123,069
Subordinated notes	99,374	99,335
Carrying Amount [Member] \| Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	9,301,774	12,028,132
Securities held to maturity, net of allowance for credit losses of $262 at March 31, 2023 and $158 at December 31, 2022	3,711,579	2,639,083
Cash surrender value of life insurance policies	190,601	190,188
Accrued interest receivable	191,883	243,682
Deposits	42,184,155	43,954,196
Federal funds purchased	57,450	51,650
Repurchase agreements	4,237,444	4,660,641
Junior subordinated deferrable interest debentures	123,083	123,069
Subordinated notes	99,374	99,335
Accrued interest payable	24,612	18,444
Carrying Amount [Member] \| Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net	17,254,506	16,927,348
Estimated Fair Value [Member] \| Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	9,301,774	12,028,132
Securities held to maturity, net of allowance for credit losses of $262 at March 31, 2023 and $158 at December 31, 2022	3,601,757	2,467,865
Cash surrender value of life insurance policies	190,601	190,188
Accrued interest receivable	191,883	243,682
Deposits	42,158,490	43,920,741
Federal funds purchased	57,450	51,650
Repurchase agreements	4,237,444	4,660,641
Junior subordinated deferrable interest debentures	123,712	123,712
Subordinated notes	96,246	97,014
Accrued interest payable	24,612	18,444
Estimated Fair Value [Member] \| Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net	$ 16,763,098	$ 16,343,417

Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage. Excludes amount for disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Carrying amount as of the balance sheet date of amounts which could be received based on the terms of the insurance contract upon surrendering life policies owned by the entity.

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Amount, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

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The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

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Amount of short term borrowing where a bank borrows, at the federal funds rate, from another bank.

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Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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