Fair Value - Financial Instruments not Required to be Carried at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Financial assets:
Investment securities held-to-maturity	$ 3,250,275	$ 3,262,509
Lease and lease commitments excluded
Financing leases	437,400	434,700
Deposit liabilities with no defined or contractual maturity	16,900,000	17,000,000
Book Value
Financial assets:
Cash and cash equivalents	1,314,579	1,170,190
Investment securities held-to-maturity	3,724,908	3,790,650
Loans held for sale	1,547
Loans	13,855,637	13,973,608
Financial liabilities:
Time deposits	3,354,266	3,298,370
Short-term borrowings	250,000	250,000
Estimated Fair Value
Financial assets:
Cash and cash equivalents	1,314,579	1,170,190
Investment securities held-to-maturity	3,250,275	3,262,509
Loans held for sale	1,547
Loans	13,348,446	13,373,785
Financial liabilities:
Time deposits	3,336,034	3,280,119
Short-term borrowings	249,578	249,312
Estimated Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets:
Cash and cash equivalents	240,738	258,057
Estimated Fair Value | Significant Other Observable Inputs (Level 2)
Financial assets:
Cash and cash equivalents	1,073,841	912,133
Investment securities held-to-maturity	3,250,275	3,262,509
Loans held for sale	1,547
Financial liabilities:
Time deposits	3,336,034	3,280,119
Short-term borrowings	249,578	249,312
Estimated Fair Value | Significant Unobservable Inputs (Level 3)
Financial assets:
Loans	$ 13,348,446	$ 13,373,785