Net income per share and common dividends - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Stock Appreciation Rights (SARs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of SARs outstanding	0	0	176,360
Anti-dilutive securities	0
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of RSUs outstanding	344,639	370,364	716,452
Anti-dilutive securities	0
Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Cash dividends	$ 12.2	$ 45.1

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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