Deposits - Additional Information About Corporation's Deposits (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Deposit Liability [Line Items]
Deposits from foreign sources (primarily Mexico)	$ 1,253,790	$ 1,219,463
Non-interest-bearing public funds deposits	13,745,461	14,441,820
Interest-bearing public funds deposits	27,938,153	28,280,928
Total deposits not covered by deposit insurance	21,428,987	22,972,618
Time deposits not covered by deposit insurance	2,903,249	2,744,112
Public Funds [Member]
Deposit Liability [Line Items]
Non-interest-bearing public funds deposits	481,175	759,819
Interest-bearing public funds deposits	$ 566,995	$ 625,104

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.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1406
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Amount of uninsured deposit liability.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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The aggregate of all foreign interest-bearing and noninterest-bearing deposit liabilities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
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-Subparagraph (SX 210.9-03(12)(a))
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The aggregate amount of all domestic and foreign noninterest-bearing deposits liabilities held by the entity.

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Amount of uninsured time deposit liability in excess of Federal Deposit Insurance Corporation (FDIC) insurance limit or similar state deposit insurance regime in United States of America (US). Excludes time deposit that is otherwise uninsured.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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