Shareholders' equity - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 31,515	$ 20,306	$ 20,146
Total income tax benefit	8,082	4,297	4,354
Stock-based compensation net of tax	23,433	16,009	15,792
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	12,806	11,686	9,699
PSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	18,709	8,620	9,277
PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 0	$ 0	$ 1,170

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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