Share-based compensation - Narrative (Details) - USD ($)	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Share-based compensation
Income tax benefit from compensation expense	$ 100,000	$ 100,000
Restricted stock units
Share-based compensation
Fair value of vested stock	500,000	1,400,000
Income tax benefit from compensation expense	100,000	300,000
Unrecognized share based compensation	$ 800,000
Weighted average period for recognition of unrecognized compensation cost (in years)	10 months 24 days
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	$ 5,700,000
Weighted average period for recognition of unrecognized compensation cost (in years)	2 years 7 months 6 days
LTIP awards linked to other performance conditions
Share-based compensation
Fair value of vested stock		1,700,000
Income tax benefit from compensation expense		$ 400,000
Unrecognized share based compensation	$ 3,600,000
Weighted average period for recognition of unrecognized compensation cost (in years)	1 year 7 months 6 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)	1,300,000
Nonemployee Director Stock Plan
Share-based compensation
Shares available for future grant (in shares)	168,177

Represents the number of years used in the calculation of total return to shareholders.

No definition available.

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- Definition

Represents the high end of range of payout depending on achievement of the goals.

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- Definition

Represents the low end of range of payout depending on achievement of the goals.

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- Definition

Represents the number of shares that could be issued upon vesting of share-based payment awards and achievement of performance goals.

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- Definition

Represents the number of authorized but unissued shares that could be issued under the equity-based compensation plan.

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Award Performance Period

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- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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- Definition

Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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- Definition

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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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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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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