SEGMENT AND GEOGRAPHICAL INFORMATION (Revenue by Country) (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Revenue	$ 134,950	$ 123,932
NETHERLANDS [Member]
Segment Reporting Information [Line Items]
Revenue	45,776	42,522
GERMANY [Member]
Segment Reporting Information [Line Items]
Revenue	58,197	53,326
UNITED STATES [Member]
Segment Reporting Information [Line Items]
Revenue	25,189	22,585
Other Countries [Member]
Segment Reporting Information [Line Items]
Revenue	$ 5,788	$ 5,499

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Name:	us-gaap_Revenues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration