SIGNIFICANT ACCOUNTING POLICIES (Revenue Recognition and Deferred Revenue) (Details)	12 Months Ended
Dec. 31, 2017
Minimum
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Service interval	49 days
Maximum
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Service interval	98 days

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.

No definition available.

Name:	us-gaap_RevenueRecognitionMultipleDeliverableArrangementsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration