Annual fair value limit on stock purchased under employee stock purchase plan.

No definition available.

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- Definition

Stock options exercisable period.

+ References

No definition available.

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- Definition

Represents the compensation cost capitalized during the period arising from equity-based compensation arrangements (for example, shares of stock, units, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ 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
-Subparagraph (h)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ 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
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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- Definition

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

+ References

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

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
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- Definition

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

+ 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

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.

+ References

No definition available.

+ Details

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- Definition

The highest percentage of annual salary that an employee is permitted to utilize with respect to the plan.

+ References

+ Details

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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

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Period Type:	instant

- Definition

Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

+ References

+ Details

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- Definition

Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest exercisable or convertible options. 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.

+ References

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-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)(2)
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- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

For net-share settlement of share-based awards when the employer settles employees' income tax withholding obligations, this element represents the number of shares the employees use to repay the employer.

+ References

No definition available.

+ Details

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- Definition

Number of shares issued during the period as a result of an employee stock purchase plan.

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- Details

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Stock Award Plan - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense included in provision for income taxes	$ 4,900,000
Capitalized stock-based compensation costs	0	$ 0	$ 0
Unrecognized compensation cost	$ 61,300,000
Unrecognized compensation expense expected to recognized over weighted-average period, in years	2 years 4 months 24 days
Common stock shares reserved for issuance under future share-based awards	4,900
Shares settled for tax withholding	695	606	648
Stock options, contractual terms	7 years
Aggregate intrinsic value of stock options outstanding	$ 0
Aggregate intrinsic value of stock options exercisable	$ 0
Share price	$ 9.64
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payroll deductions	20.00%
Offering price percentage	15.00%
Shares purchased under the ESPP	1,600	1,000
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual fair value limit on shares purchased	$ 25,000
Service-based share awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 50,900,000
Unrecognized compensation expense expected to recognized over weighted-average period, in years	2 years 7 months 6 days
Share based compensation award vesting period	4 years
Deferred share units awarded to directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation award vesting period	1 year
Awards Granted Under Financial Performance [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation award vesting period	3 years
Awards Granted Under Financial Performance [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation award vesting period	4 years
Performance-Based Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 1,200,000
Unrecognized compensation expense expected to recognized over weighted-average period, in years	1 year
Market-Based Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 9,200,000
Unrecognized compensation expense expected to recognized over weighted-average period, in years	1 year 9 months 18 days
Share based compensation award vesting period	3 years