NET INCOME PER SHARE (Details) - shares shares in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Weighted-average number of basic common shares outstanding (in shares)	42,389	47,268	43,540	47,887
Weighted-average dilutive stock options, restricted stock units and performance share units (in shares)	198	230	191	270
Assumed conversion of Convertible Senior Notes (in shares)	244	253	216	373
Weighted-average number of diluted common and common equivalent shares outstanding (in shares)	42,831	47,751	43,947	48,530
Unvested Stock Awards Outstanding and Convertible Debt Securities
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive potential common shares (in shares)	1,264	1,428	1,299	1,366
Convertible Debt
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive potential common shares (in shares)	1,000		1,000

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of convertible debt securities using the if-converted method.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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