Employee Benefit Plans - Stock Incentive Plans (Details) - Stock Incentive Plans - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Stock incentive plans
Common stock reserved for future issuance	8,000,000
Period of stock options and restricted stock issued	10 years
Number of shares available for grant	911,997	2,046,199
Pre-tax stock-based employee compensation expense	$ 7.9	$ 6.4	$ 6.6
After tax stock-based employee compensation expense	$ 6.1	$ 4.9	$ 5.1