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Share based compensation arrangement by share based payment award number of shares available for grant under stock incentive plan.

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Share-based compensation arrangement by share-based payment award options grants in period gross at below market price.

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

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Amount of tax benefit from exercise of option under share-based payment arrangement.

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Discount rate from fair value on offering date that participants pay for shares.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Net number of share options (or share units) granted during the period.

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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for fully vested and expected to vest options outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Stock Incentive Plans - Additional Information (Detail)	12 Months Ended
Stock Incentive Plans - Additional Information (Detail)	Dec. 31, 2020 USD ($) Installment shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
New grants of stock option \| shares	0
Outstanding options expiration period from the date of grant	10 years
Share-based compensation expense included in selling, general and administrative expenses	$ 3,400,000	$ 7,200,000	$ 5,500,000
Share-based compensation, income tax benefits	$ 800,000	$ 1,300,000	$ 1,500,000
2019 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved for issuance \| shares	293,000
Percentage in payroll deductions to acquire shares	15.00%
Discount rate of fair market value available for share purchase	85.00%
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options exercisable period after date of grant	10 years
Weighted average fair value of stock options, granted \| $ / shares			$ 36.41
Stock options granted with an exercise price below market price \| shares	0	0	0
Intrinsic value of stock options exercised	$ 4,100,000	$ 3,800,000	$ 2,500,000
Fair value of shares vested during the period	43,000	312,000	312,000
Unrecognized compensation expense	$ 2,400,000
Weighted average remaining amortization period	5 years 2 months 12 days
Stock Options [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding stock options vesting period	8 years
Stock Options [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding stock options vesting period	4 years
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options exercisable period after date of grant	1 year
Fair value of shares vested during the period	$ 3,800,000	5,800,000	4,000,000.0
Unrecognized compensation expense	$ 8,600,000
Weighted average remaining amortization period	2 years 10 months 24 days
Number of equal annual installments in which restricted stock units generally vest \| Installment	4
Performance Share Units (“PSUs”) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of shares vested during the period	$ 743,000	$ 296,000	$ 0
Vesting period	3 years
Maximum payout percentage	200.00%
Two Thousand And Twenty Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares reserved for issuance \| shares	375,000
Aggregate number of shares for which incentive stock options may be granted under the Plan \| shares	375,000
Two Thousand And Fifteen Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for grant \| shares	303,462