Loans - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Financing Receivable, Troubled Debt Restructuring [Line Items]
Net deferred costs	$ 44.9		$ 43.1
Accrued interest receivable	39.5		39.4
Interest income on nonaccrual loans	0.2	$ 0.1
Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Remaining fair value adjustment for loans acquired	$ 163.4		$ 174.0
Percentage of fair value adjustment for loans acquired	4.60%		4.80%