Purchase commitments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Purchase Obligation, Fiscal Year Maturity [Abstract]
Total purchase commitment	$ 132.8
Purchase commitment, year one	$ 125.7
Purchase commitment period	5 years
Materials purchased under commitment, amount	$ 199.6	$ 110.7	$ 108.0