The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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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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No definition available.

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The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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SHARE-BASED COMPENSATION - Stock Options Outstanding and Exercisable (Detail) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices Per Share - Lower Range	$ 11.07
Range of Exercise Prices Per Share - Upper Range	$ 44.59
Options Outstanding - Stock Option Shares	5,330	7,304	12,680	15,836
Options outstanding - weighted-average remaining term (Yrs)	5 years
Options Outstanding - Weighted-Average Exercise Price Per Share	$ 28.54	$ 28.03	$ 26.28	$ 25.47
Options Exercisable - Stock Option Shares	3,917	4,208	8,986
Options Exercisable - Weighted-Average Exercise Price Per Share	$ 27.14
$11.07 - $24.28
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices Per Share - Lower Range	11.07
Range of Exercise Prices Per Share - Upper Range	$ 24.28
Options Outstanding - Stock Option Shares	1,181
Options outstanding - weighted-average remaining term (Yrs)	1 year 9 months 18 days
Options Outstanding - Weighted-Average Exercise Price Per Share	$ 20.76
Options Exercisable - Stock Option Shares	1,181
Options Exercisable - Weighted-Average Exercise Price Per Share	$ 20.76
$24.75 - $28.97
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices Per Share - Lower Range	24.75
Range of Exercise Prices Per Share - Upper Range	$ 28.97
Options Outstanding - Stock Option Shares	1,718
Options outstanding - weighted-average remaining term (Yrs)	4 years 9 months 18 days
Options Outstanding - Weighted-Average Exercise Price Per Share	$ 27.76
Options Exercisable - Stock Option Shares	1,026
Options Exercisable - Weighted-Average Exercise Price Per Share	$ 26.95
$29.04 - $31.21
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices Per Share - Lower Range	29.04
Range of Exercise Prices Per Share - Upper Range	$ 31.21
Options Outstanding - Stock Option Shares	1,226
Options outstanding - weighted-average remaining term (Yrs)	5 years 9 months 18 days
Options Outstanding - Weighted-Average Exercise Price Per Share	$ 30.77
Options Exercisable - Stock Option Shares	1,221
Options Exercisable - Weighted-Average Exercise Price Per Share	$ 30.77
$31.22 - $37.22
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices Per Share - Lower Range	31.22
Range of Exercise Prices Per Share - Upper Range	$ 37.22
Options Outstanding - Stock Option Shares	1,134
Options outstanding - weighted-average remaining term (Yrs)	7 years 6 months
Options Outstanding - Weighted-Average Exercise Price Per Share	$ 34.44
Options Exercisable - Stock Option Shares	488
Options Exercisable - Weighted-Average Exercise Price Per Share	$ 33.86
$38.76 - $44.59
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices Per Share - Lower Range	38.76
Range of Exercise Prices Per Share - Upper Range	$ 44.59
Options Outstanding - Stock Option Shares	71
Options outstanding - weighted-average remaining term (Yrs)	9 years 3 months 18 days
Options Outstanding - Weighted-Average Exercise Price Per Share	$ 44.21
Options Exercisable - Stock Option Shares	1
Options Exercisable - Weighted-Average Exercise Price Per Share	$ 38.76