Segment and Geographical Information (Revenue by Country) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
Jun. 30, 2013	Jun. 30, 2012
Segment Reporting Information [Line Items]
Revenue	$ 57,277	$ 47,143
Netherlands [Member]
Segment Reporting Information [Line Items]
Revenue	26,172	23,485
United States [Member]
Segment Reporting Information [Line Items]
Revenue	19,494	17,313
Other [Member]
Segment Reporting Information [Line Items]
Revenue	$ 11,611	$ 6,345

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=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

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