Short-Term Borrowings and Long-Term Debt - Short-Term Borrowings and FHLB Advances (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Short-Term Debt [Line Items]
Short-term borrowings	$ 19,173	$ 0
FHLB Advances - floating	$ 3,500,000	0
Weighted-average contractual interest rates for FHLB advances	5.52%
Bank Term Funding Program
Short-Term Debt [Line Items]
Interest rate short-term borrowings	4.37%
Short-term borrowings	$ 0	$ 4,500,000
Parent Company | Junior Subordinated Debt
Short-Term Debt [Line Items]
Weighted-average rate (as a percent)	7.14%	6.87%
Long-term debt total	$ 31,768	$ 148,249
Minimum
Short-Term Debt [Line Items]
Interest rate short-term borrowings	4.75%
Interest Rates	5.49%
Maximum
Short-Term Debt [Line Items]
Interest rate short-term borrowings	4.83%
Interest Rates	5.56%