FAIR VALUE MEASUREMENTS (Schedule of Changes in Level 3 Contingent Consideration Obligation Measured) (Details) - Seculert Ltd [Member] $ in Thousands	12 Months Ended
Dec. 31, 2017 USD ($)
Business Acquisition, Contingent Consideration [Line Items]
Fair value at the beginning of the year
Acquisition date fair value of contingent consideration related to investment in Seculert (see Note 1c)	1,981
Changes in the fair value of contingent consideration in Seculert, net	(431)
Fair value at the end of the year	$ 1,550

Acquisition date fair value of contingent consideration related to investment.

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- Definition

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.

+ References

No definition available.

+ Details

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- Definition

Amount of increase (decrease) in the value of a contingent consideration liability, including, but not limited to, differences arising upon settlement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e7008-128479

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- Definition

Fair value of contingent consideration in a business combination that is classified in shareholders' equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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