SHAREHOLDERS' EQUITY (Schedule of Stock Option Activity) (Details) - Employee Stock Option [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Number of options
Outstanding at January 1, 2018	1,676,130
Granted	308,884
Exercised	(661,379)
Cancelled	(1,924)
Forfeited	(136,864)
Outstanding at December 31, 2018	1,184,847	1,676,130
Exercisable	410,237
Weighted average exercise price
Outstanding at January 1, 2018	$ 23.07
Granted	15.94
Exercised	28.55
Cancelled	22.76
Forfeited	7.22
Outstanding at December 31, 2018	19.82	$ 23.07
Exercisable	$ 36.24
Weighted-average remaining contractual term (in years)
Outstanding at December 31	4 years 5 months 20 days	4 years 5 months 12 days
Exercisable	3 years 7 months 17 days
Aggregate intrinsic value
Outstanding at January 1, 2018	$ 115,390
Outstanding at December 31, 2018	104,731	$ 115,390
Exercisable	$ 29,523

Share Based Compensation Arrangement By Share Based Payment Award Options Aggregate Intrinsic Value [Abstract]

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Share based compensation arrangement by share based payment award options cancelled in period.

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Share based compensation arrangement by share based payment award options cancelled in period weighted average exercise price.

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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 or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Net number of share options (or share units) granted during the period.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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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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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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