v3.26.1
Fair value measurements - Narrative (Details)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2026
USD ($)
Mar. 31, 2026
USD ($)
Jun. 30, 2025
USD ($)
Jun. 30, 2026
USD ($)
Jun. 30, 2025
USD ($)
Dec. 31, 2025
USD ($)
Fair Value Disclosures [Abstract]            
Investments used to satisfy nonqualified benefit plans obligations $ 70.4   $ 64.1 $ 70.4 $ 64.1 $ 67.4
Unrealized gains (losses) on investments, net of insurance proceeds $ 4.6   3.0 $ 4.1 $ 2.6  
Investment withdrawal, cash amount   $ 4.0 $ 5.0      
Investment withdrawal, percentage   1.25 1.25