Stock-Based Compensation - Additional Information (Detail) - USD ($)	12 Months Ended
Dec. 31, 2020	Jun. 18, 2015
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares available for issuance under plan	250,000
Percentage of market value	85.00%
Percentage of employee's payroll deductions limited to employee's compensation	10.00%
Maximum Stock value of shares purchased by employees if one thousand shares purchased	$ 25,000
Maximum number of shares that employee can purchase each period	250
Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs related to non-vested awards granted	$ 6,300,000
2015 Omnibus Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
1995 Stock option expiry date	Jul. 28, 2015
Maximum number of shares available for issuance under plan		9,625,000
Number of shares available for future grants	5,100,000
2015 Omnibus Equity Incentive Plan [Member] \| Full Value Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award settled against shares	1.2
2015 Omnibus Equity Incentive Plan [Member] \| Partial Value Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award settled against shares	1.0
2015 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting period	4 years
Stock option expiration period	10 years
2015 Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting period	48 months
Vested stock options exercised period following termination	90 days
2015 Plan [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting period	12 months
2005 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for future grants	0

Awards settled in shares adjustments against share reserve.

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- Definition

Maximum shares purchased by employees.

+ References

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- Definition

Maximum stock value of shares purchased by employees.

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- Definition

Percentage of employee compensation for employee payroll deduction.

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- Definition

Percentage of fair market value of share.

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- Definition

Share based compensation arrangement by share based payment award options exercise period following termination.

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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- Definition

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

Date the equity-based award expires, in CCYY-MM-DD format.

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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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- Definition

Number of shares authorized for issuance under share-based payment arrangement.

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- Definition

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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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- Definition

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.

+ References

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