Duration of Each Purchase Period in Each Offering Period

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- Definition

Exercise Price As Percentage Of Fair Market Value On Grant Date, Minimum

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Factor used to determine number of options units to be granted

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- Definition

Number of Purchase Period in Each Offering Period

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Number of Stock-based Compensation Plans

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Purchase Price as Percentage of Lower of Fair Market Value on First Day of Offering Period or Purchase Date.

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Award Expiration Period

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- Definition

Share-Based Compensation Arrangement By Share Based Payment Award Employee Shares Purchased For Award

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- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Aggregate number of common shares reserved for future issuance.

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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- Definition

The highest percentage of annual salary that an employee is permitted to utilize with respect to the plan.

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- Definition

Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

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- Definition

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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

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STOCK PLANS AND SHARE BASED COMPENSATION (Details)	12 Months Ended
STOCK PLANS AND SHARE BASED COMPENSATION (Details)	Dec. 31, 2018 USD ($) plans purchaseperiods shares	Dec. 31, 2017 USD ($) shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock-based compensation plans \| plans	3
Number of shares available for future issuance \| shares	1,600,000
Stock-based compensation expense \| $	$ 21,580,000	$ 24,700,000	$ 20,900,000
2016 Incentive Award Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance under stock option and stock purchase plans \| shares	1,100,000
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number \| shares	400,000
Incentive Stock Options [Member] \| 2007 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price of stock options as percentage of fair market value on date of grant, minimum	100.00%
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards vesting period	4 years
Stock-based compensation expense \| $	$ 16,600,000	15,200,000	13,000,000
Restricted Stock Units (RSUs) [Member] \| Directors Equity Compensation Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Factor used to determine the number of options/units to be granted \| $	$ 100,000
Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum percentage of employee's compensation eligible for payroll deductions	15.00%
Purchase price of the purchase plan as percentage of the lower of the fair market value on the first day of each offering period or on the purchase date	85.00%
Number of purchase period in each offering period \| purchaseperiods	1
Duration of each purchase period in each offering period	6 months
Shares reserved for issuance \| shares	3,500,000
Number of shares purchased \| shares	3,100,000
Common stock reserved for future issuance under stock option and stock purchase plans \| shares	400,000
Stock-based compensation expense \| $	$ 1,600,000	$ 1,300,000	$ 1,300,000
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards vesting period	4 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number \| shares	335,000	511,000	697,000	1,030,000
Stock-based compensation expense \| $			$ 200,000
Stock Options [Member] \| 2007 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards vesting period	48 months
Awards expiration period, maximum	10 years
Stock Options [Member] \| Directors Equity Compensation Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Factor used to determine the number of options/units to be granted \| $	$ 100,000
Stock Options and Restricted Stock Units (RSUs) [Member] \| Directors Equity Compensation Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Factor used to determine the number of options/units to be granted \| $	$ 100,000