Subsequent events (Details) $ / shares in Units, € in Millions, $ in Millions	Mar. 15, 2024 USD ($)	Mar. 11, 2024 USD ($) tranche $ / shares	Feb. 07, 2024 USD ($) employee	Feb. 07, 2024 EUR (€) employee	Jan. 26, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Oct. 31, 2022 USD ($)	May 31, 2022 $ / shares	Oct. 31, 2021 USD ($)	Oct. 31, 2020 USD ($)
Glencore Convertible Notes
Subsequent Event [Line Items]
Debt instrument, face amount						$ 225.3
Convertible Debt | Glencore Convertible Notes
Subsequent Event [Line Items]
Debt instrument, face amount						$ 225.3	$ 208.1	$ 200.0		$ 0.0	$ 0.0
Debt instrument, convertible, conversion price (in dollars per share) | $ / shares									$ 9.95
Subsequent Event
Subsequent Event [Line Items]
Construction payable					$ 58.6
Tenant improvements payable					14.5
Payments for construction in process	$ 53.5
Subsequent Event | Convertible Debt | Glencore Convertible Notes
Subsequent Event [Line Items]
Debt instrument, face amount		$ 75.0
Debt instrument, convertible, conversion price (in dollars per share) | $ / shares		$ 0.53
Debt instrument, number of tranches | tranche		2
Debt instrument, maturity, additional term		5 years
Debt instrument, modification date, term after initial funding		1 month
Debt instrument, convertible, conversion price adjustment, volume weighted average trading price, duration from modification date		30 days
Debt instrument, convertible, conversion price adjustment, premium, percentage		25.00%
Subsequent Event | Spoke Network
Subsequent Event [Line Items]
Government assistance, amount approved for grant			$ 7.1	€ 6.4
Government assistance, number of employees required to engage | employee			38	38
Subsequent Event | Minimum | Pike
Subsequent Event [Line Items]
Loss contingency, damages sought, value					39.0
Subsequent Event | Maximum | Pike
Subsequent Event [Line Items]
Loss contingency, damages sought, value					$ 53.0