Loans and Allowance for Credit Losses, Loans by Portfolio Type (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest	$ 7,160,790	$ 7,101,490
Loans, variable rate of interest	18,966,599	18,475,612
Nonaccrual	60,004	74,360
Total	26,187,393	25,651,462
Credit Commitments [Abstract]
Outstanding commitments to extend credit	16,200,000
Outstanding standby letters of credit	617,000
Commercial [Member]
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest	3,498,856	3,494,944
Loans, variable rate of interest	12,048,961	11,750,021
Nonaccrual	25,266	36,102
Total	15,573,083	15,281,067
Commercial real estate [Member]
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest	620,233	601,044
Loans, variable rate of interest	5,257,845	5,064,265
Nonaccrual	6,601	6,697
Total	5,884,679	5,672,006
Loans to individuals [Member]
Loan receivables disclosure [Abstract]
Loans, fixed rate of interest	3,041,701	3,005,502
Loans, variable rate of interest	1,659,793	1,661,326
Nonaccrual	28,137	31,561
Total	$ 4,729,631	$ 4,698,389

-- None. No documentation exists for this element. --

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- Definition

Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

+ References

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- Definition

Amortized cost of financing receivable on nonaccrual status. Excludes net investment in lease.

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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Amount of loan with fixed rate of interest.

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Amount of loan with variable or adjustable rate of interest.

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Unused amount of commitments to extend credit to customers.

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