Fair Value - Financial Instruments not Required to be Carried at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Financial assets:
Investment securities held-to-maturity	$ 3,475,143	$ 3,574,856
Lease and lease commitments excluded
Financing leases	432,800	379,800
Deposit liabilities with no defined or contractual maturity	16,800,000	17,900,000
Book Value
Financial assets:
Cash and cash equivalents	1,072,812	1,739,897
Investment securities held-to-maturity	3,853,697	4,041,449
Loans held for sale		190
Loans	13,808,542	13,973,688
Financial liabilities:
Time deposits	3,402,264	3,456,158
Short-term borrowings	250,000	500,000
Estimate of Fair Value Measurement [Member]
Financial assets:
Cash and cash equivalents	1,072,812	1,739,897
Investment securities held-to-maturity	3,475,143	3,574,856
Loans held for sale		192
Loans	13,293,256	13,385,683
Financial liabilities:
Time deposits	3,388,783	3,432,330
Short-term borrowings	249,951	495,306
Estimate of Fair Value Measurement [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets:
Cash and cash equivalents	252,209	185,015
Estimate of Fair Value Measurement [Member] | Significant Other Observable Inputs (Level 2)
Financial assets:
Cash and cash equivalents	820,603	1,554,882
Investment securities held-to-maturity	3,475,143	3,574,856
Loans held for sale		192
Financial liabilities:
Time deposits	3,388,783	3,432,330
Short-term borrowings	249,951	495,306
Estimate of Fair Value Measurement [Member] | Significant Unobservable Inputs (Level 3)
Financial assets:
Loans	$ 13,293,256	$ 13,385,683