Long-Term Incentive Plans - Summary of Fair Value Assumptions (Detail) - PSUs [Member] - $ / shares				9 Months Ended
Jul. 01, 2019	Apr. 01, 2019	Jan. 01, 2019	Sep. 30, 2019
Share Price Target 12.50 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share price targets				$ 12.50
Risk-free interest rate	1.73%	2.28%	2.44%
Expected volatility	57.00%	50.00%	54.00%
Calculated fair value per PSU	$ 2.63	$ 4.22	$ 6.76
Share Price Target 15.00 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share price targets				15.00
Risk-free interest rate	1.73%	2.28%	2.44%
Expected volatility	57.00%	50.00%	54.00%
Calculated fair value per PSU	$ 2.05	$ 3.43	$ 5.86
Share Price Target 17.50 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share price targets				$ 17.50
Risk-free interest rate	1.73%	2.28%	2.44%
Expected volatility	57.00%	50.00%	54.00%
Calculated fair value per PSU	$ 1.64	$ 2.80	$ 5.11

Share-based compensation arrangement by share-based payment award, fair value assumptions, share price targets.

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

+ 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 (f)(2)(ii)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own 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
-Subparagraph (f)(2)(iv)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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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

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- Definition

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

+ References

No definition available.

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