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Stock-based compensation - Narrative (Detail) - USD ($)														12 Months Ended
Stock-based compensation - Narrative (Detail) - USD ($)	Dec. 22, 2021	Sep. 24, 2021	Jun. 23, 2021	Mar. 19, 2021	Dec. 23, 2020	Sep. 23, 2020	Jun. 26, 2020	Mar. 18, 2020	Dec. 18, 2019	Sep. 20, 2019	Jun. 21, 2019	Apr. 05, 2019	Mar. 20, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	May 09, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation cost														$ 80,548,000	$ 72,709,000	$ 82,802,000
Tax benefits recognized in relation to stock-based compensation														$ 21,857,000	$ 21,832,000	18,921,000
Options granted, contractual period, years														10 years
Dividends paid per share (in usd per share)	$ 0.1075	$ 0.1075	$ 0.1075	$ 0.1075	$ 0.0975	$ 0.0975	$ 0.0975	$ 0.0975	$ 0.085	$ 0.085	$ 0.085		$ 0.085	$ 0.1075	$ 0.0975
Cash received from the exercise of stock option														$ 23,168,000	$ 14,062,000	10,690,000
Tax benefits from the exercise of stock option														6,927,000	7,381,000	2,966,000
Unrecognized stock-based compensation cost for options														$ 24,199,000
Restricted Stock Unit vesting right (in shares)														1
Restricted Stock Unit vesting right, fair value (in shares)														1
Performance Units vesting right (in shares)														1
Performance Units vesting right, fair value (in shares)														1
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Excess tax benefit on stock-based compensation														$ 4,191,000	$ 7,310,000	$ 2,743,000
Weighted average remaining requisite vesting period														3 years 2 months 12 days
Restricted Share Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining requisite vesting period														2 years 3 months 18 days
Unrecognized stock-based compensation cost														$ 18,045,000
Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining requisite vesting period																1 year 9 months 18 days
Unrecognized stock-based compensation cost																$ 58,752,000
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of fair value per share allowed to eligible employees to purchase through payroll deductions														90.00%
Maximum percentage of employee's base salary allowed to be purchased														15.00%
Maximum dollar amount of common shares allowed to be purchased														$ 25,000
Common shares reserved for issuance														4,200,000
Issuance of common shares under the employee stock purchase plan (Note 18) (in shares)														285,657	315,245	264,440
Compensation expense for ESPP														$ 1,420,000	$ 1,299,000	$ 1,083,000
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award, vesting period, years														3 years
Minimum \| Restricted Share Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award, vesting period, years														3 months
Minimum \| Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award, vesting period, years														6 months
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award, vesting period, years														5 years
Maximum \| Restricted Share Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award, vesting period, years														4 years
Maximum \| Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award, vesting period, years														3 years
2007 Omnibus Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common shares authorized for issuance												23,000,000		23,858,823
Amended Omnibus Plan, increase in number of common shares authorized for issuance												8,000,000
2017 Omnibus Incentive Compensation Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common shares authorized for issuance																	15,000,000