Share-based compensation - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Share-based compensation
Income tax benefit from compensation expense	$ 100,000	$ 100,000
Restricted stock units
Share-based compensation
Fair value of vested stock	400,000	500,000
Income tax benefit from compensation expense	0	100,000
Unrecognized share based compensation	$ 0
Long-term Incentive Plan
Share-based compensation
Payment award, low end of range	0.00%
Payment award, high end of range	220.00%
Measurement period for total return to shareholders (in years)	3 years
Award performance period (in years)	3 years
LTIP linked to TRS
Share-based compensation
Fair value of vested stock	$ 0	0
Unrecognized share based compensation	$ 8,200,000
Weighted average period for recognition of unrecognized compensation cost (in years)	2 years 1 month 6 days
LTIP awards linked to other performance conditions
Share-based compensation
Fair value of vested stock	$ 0	$ 0
Unrecognized share based compensation	$ 1,100,000
Weighted average period for recognition of unrecognized compensation cost (in years)	9 months 18 days
Equity and Incentive Plan
Share-based compensation
Shares available for future issuance (in shares)	2,500,000
Number of share issuable upon vesting and achievement of performance goals (in shares)	1,600,000
Nonemployee Director Stock Plan
Share-based compensation
Shares available for future grant (in shares)	41,964