Lease contracts - Summary of Operating Leases Future Minimum Payments (Details) - USD ($) $ in Millions	Sep. 30, 2026	Dec. 31, 2025
Lessee, Lease, Description [Line Items]
Current portion	$ 1.2	$ 1.4
Year 2	1.8	1.0
Year 3	1.8	1.0
Thereafter	3.7	4.2
Total minimum lease payments	8.4	7.6
Less: Effects of discounting	(1.1)	(1.1)
Present value of lease liabilities	7.3	6.5
Less: current portion	(0.8)	(1.1)
Long-term lease liabilities	6.5	5.4
Real Estate
Lessee, Lease, Description [Line Items]
Current portion	1.2	1.3
Year 2	1.8	1.0
Year 3	1.8	1.0
Thereafter	3.7	4.2
Total minimum lease payments	8.4	7.5
Less: Effects of discounting	(1.1)	(1.1)
Present value of lease liabilities	7.3	6.4
Less: current portion	(0.8)	(1.0)
Long-term lease liabilities	$ 6.5	$ 5.4
Weighted average remaining lease term (years)	5 years 8 months 1 day	6 years 11 months 12 days
Weighted average discount rate	5.58%	5.02%
Other assets
Lessee, Lease, Description [Line Items]
Current portion	$ 0.0	$ 0.1
Year 2	0.0	0.0
Year 3	0.0	0.0
Thereafter	0.0	0.0
Total minimum lease payments	0.0	0.1
Less: Effects of discounting	0.0	0.0
Present value of lease liabilities	0.0	0.1
Less: current portion	0.0	(0.1)
Long-term lease liabilities	$ 0.0	$ 0.0
Weighted average remaining lease term (years)	3 days	2 months 8 days
Weighted average discount rate	0.02%	0.07%

Lessee, Operating Lease, Liability, to be Paid, Due after Year Two

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Amount of lessee's undiscounted obligation for lease payment for operating lease.

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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Amount of lessee's undiscounted obligation for lease payment for operating lease having initial or remaining lease term in excess of one year to be paid in remainder of current fiscal year.

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Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for operating lease.

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Present value of lessee's discounted obligation for lease payments from operating lease.

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Present value of lessee's discounted obligation for lease payments from operating lease, classified as current.

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Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent.

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- Definition

Weighted average discount rate for operating lease calculated at point in time.

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Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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