Share-based compensation - Schedule of Common Stock Granted to Non-employee Directors (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Income tax benefit	$ 0.3	$ 1.4	$ 1.5
Common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (in shares)	0	40,450	35,720
Fair value	$ 0.0	$ 1.5	$ 1.5
Income tax benefit	$ 0.0	$ 0.4	$ 0.4