Investment Securities - Schedule of Carrying Value of Held-to-Maturity Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Held-to-maturity securities pledged	$ 7,294,055	$ 7,860,725
Pledged for deposits
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Held-to-maturity securities pledged	1,733,451	1,926,373
Pledged for borrowing capacity, repurchase agreements, and other
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Held-to-maturity securities pledged	$ 5,560,604	$ 5,934,352

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
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3D
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-3D

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3C
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-3C

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