Fair value measurements - Narrative (Details) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025 USD ($)	Jun. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Mar. 31, 2024 USD ($)	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)
Fair Value Disclosures [Abstract]
Investments used to satisfy nonqualified benefit plans obligations	$ 66.2		$ 59.2		$ 66.2	$ 59.2	$ 59.3
Net unrealized gain (loss) on investments used to satisfy obligations under nonqualified benefit plans	$ 2.2		$ 2.4		$ 4.8	$ 5.3
Investment withdrawal, cash amount		$ 5.0		$ 9.0
Investment withdrawal, percentage		1.25

Life Insurance, Corporate or Bank Owned, Cash Withdrawn, Percentage

No definition available.

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- Definition

Unrealized Gains (Losses) On Investments, Net Of Insurance Proceeds

+ References

No definition available.

+ Details

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- References

No definition available.

+ Details

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- Definition

This item represents the amount that could be realized under a life insurance contract or contracts owned by the Entity as of the date of the statement of financial position. Such Entity-owned life insurance policies are commonly known as corporate-owned life insurance (COLI) or bank-owned life insurance (BOLI).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(12))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 325
-SubTopic 30
-Name Accounting Standards Codification
-Section 25
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481612/325-30-25-1

+ Details

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- Definition

The change in cash surrender or contract value during the period which adjusted the amount of premiums paid in determining the expense or income recognized under the contract for the period.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 325
-SubTopic 30
-Name Accounting Standards Codification
-Section 35
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481551/325-30-35-2

+ Details

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