Stockholders' equity - Schedule of Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ 957.2	$ 870.2	$ 796.5
Ending Balance	808.3	957.2	870.2
Defined benefit pension plans
Accumulated Other Comprehensive Income Loss [Line Items]
Plan settlement	(1.6)	(0.3)
Currency translation
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(269.2)	(240.4)	(233.4)
Other comprehensive income (loss)	3.7	(28.8)	(7.0)
Ending Balance	(265.5)	(269.2)	(240.4)
Accumulated Defined benefit pension plans | Defined benefit pension plans
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(63.1)	(163.3)	(214.5)
Other comprehensive income (loss)	2.0	9.9	14.9
Net actuarial gain (loss) arising during year	(16.0)	90.3	36.3
Plan settlement	1.1
Ending Balance	(76.0)	(63.1)	(163.3)
Accumulated Defined benefit pension plans | OPEB Plans
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	0.8	(0.4)	(0.3)
Other comprehensive income (loss)	(0.2)	(0.3)	(0.3)
Net actuarial gain (loss) arising during year	(0.2)	1.5	0.2
Ending Balance	0.4	0.8	(0.4)
Total Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(331.5)	(404.1)	(448.2)
Other comprehensive income (loss)	(9.6)	72.6	44.1
Ending Balance	$ (341.1)	$ (331.5)	$ (404.1)