The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&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

No definition available.

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Stock-Based Compensation (Unvested RSUs by Grant-Date Fair Value) (Detail) - Restricted Stock Units - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award
Number of Shares/Units Outstanding at Year End	6,986	5,086,000	371,000	0
Weighted-Average Remaining Contractual Life (in years)	1 year 4 months 24 days
$10.01-$15.00
Share-based Compensation Arrangement by Share-based Payment Award
Number of Shares/Units Outstanding at Year End	407,000
Weighted-Average Remaining Contractual Life (in years)	7 months 6 days
$15.01-$20.00
Share-based Compensation Arrangement by Share-based Payment Award
Number of Shares/Units Outstanding at Year End	2,973,000
Weighted-Average Remaining Contractual Life (in years)	1 year 2 months 12 days
$20.01-$25.00
Share-based Compensation Arrangement by Share-based Payment Award
Number of Shares/Units Outstanding at Year End	228,000
Weighted-Average Remaining Contractual Life (in years)	1 year
$25.01-$30.00
Share-based Compensation Arrangement by Share-based Payment Award
Number of Shares/Units Outstanding at Year End	3,360,000
Weighted-Average Remaining Contractual Life (in years)	1 year 8 months 12 days