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Investment Securities - Summary of Carrying Value of Held-to-Maturity Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Total held-to-maturity securities pledged	$ 7,860,725	$ 8,237,273
Pledged for deposits
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Total held-to-maturity securities pledged	1,926,373	1,978,445
Pledged for borrowings and other
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Total held-to-maturity securities pledged	$ 5,934,352	$ 6,258,828

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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.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

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- Definition

Pledged Financial Instruments, Not Separately Reported, Debt Securities Held-to-Maturity

+ References

No definition available.

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