Debt - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Short term borrowings	$ 271,849,000	$ 241,532,000
Maturity of federal funds purchased from correspondent banks	one business day
Maximum borrowing capacity	$ 3,000,000,000
Current borrowing available	1,700,000,000
Federal home loan bank, maximum amount available, net of deposits and advances	2,100,000,000
Letter of credit outstanding, amount	142,900,000	153,500,000
Other Correspondent Banks
Debt Instrument [Line Items]
Line of credit facility, remaining borrowing capacity	35,000,000
Outstanding drawings	$ 0	$ 0