Fair Value - Financial Instruments not Required to be Carried at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financial assets:
Investment securities held-to-maturity	$ 3,470,710	$ 3,574,856
Lease and lease commitments excluded
Financing leases	394,000	379,800
Deposit liabilities with no defined or contractual maturity	17,400,000	17,900,000
Book Value
Financial assets:
Cash and cash equivalents	1,274,266	1,739,897
Investment securities held-to-maturity	3,988,011	4,041,449
Loans held for sale		190
Loans	13,926,199	13,973,688
Financial liabilities:
Time deposits	3,284,045	3,456,158
Short-term borrowings	500,000	500,000
Estimated Fair Value
Financial assets:
Cash and cash equivalents	1,274,266	1,739,897
Investment securities held-to-maturity	3,470,710	3,574,856
Loans held for sale		192
Loans	13,250,470	13,385,683
Financial liabilities:
Time deposits	3,259,350	3,432,330
Short-term borrowings	498,175	495,306
Estimated Fair Value | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets:
Cash and cash equivalents	202,121	185,015
Estimated Fair Value | Significant Other Observable Inputs (Level 2)
Financial assets:
Cash and cash equivalents	1,072,145	1,554,882
Investment securities held-to-maturity	3,470,710	3,574,856
Loans held for sale		192
Financial liabilities:
Time deposits	3,259,350	3,432,330
Short-term borrowings	498,175	495,306
Estimated Fair Value | Significant Unobservable Inputs (Level 3)
Financial assets:
Loans	$ 13,250,470	$ 13,385,683