Short-Term Borrowings - Components and Selected Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Short-term borrowings
Short-term borrowings	$ 500,000		$ 75,000
Short-term FHLB fixed-rate advances:
Short-term borrowings
Borrowing capacity	2,800,000		2,500,000
Federal Reserve Bank Advances [Member]
Short-term borrowings
Borrowing capacity	3,800,000		1,200,000
Federal funds purchased:
Short-term borrowings
Short-term borrowings			$ 75,000
Annual interest rate			4.35%
Highest month-end balance	150,000
Average outstanding balance	$ 23,059	$ 55
Weighted-average interest rate paid (as a percent)	4.45%	1.67%
Short-term FHLB repo advance:
Short-term borrowings
Highest month-end balance	$ 400,000
Average outstanding balance	$ 156,319
Weighted-average interest rate paid (as a percent)	5.25%
Short-term FHLB fixed-rate advances:
Short-term borrowings
Short-term borrowings	$ 500,000
Weighted-average interest rate (as a percent)	4.71%
Highest month-end balance	$ 500,000
Average outstanding balance	$ 20,147
Weighted-average interest rate paid (as a percent)	4.34%