Shareholders' equity - Reconciliation of basic to diluted weighted average common shares outstanding (Detail) - shares shares in Thousands	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Equity [Abstract]
Basic (in shares)	46,981	46,898	46,774
Dilutive effect of share based awards (in shares)	323	411	653
Diluted (in shares)	47,304	47,309	47,427

No definition available.

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- Definition

Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Topic 260
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- Definition

The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
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-Name Accounting Standards Codification
-Section 50
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-URI https://asc.fasb.org//1943274/2147482662/260-10-50-1

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
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-Name Accounting Standards Codification
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-URI https://asc.fasb.org//1943274/2147482662/260-10-50-1

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