STOCK-BASED COMPENSATION - Weighted Average Assumptions used in Black Scholes Option Valuation Model (Details)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Expected annual volatility	34.00%	35.00%	40.00%
Expected term in years	4 years 6 months	4 years 6 months	4 years 4 months 24 days
Risk-free interest rate	2.60%	1.90%	1.20%
Expected annual dividend yield	0.40%	0.50%	0.60%

No definition available.

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

Weighted average expected volatility rate of share-based compensation awards.

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- Definition

Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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