Revenue from Contracts with Customers (Details 2) $ in Thousands	9 Months Ended
Sep. 30, 2018 USD ($)
Contract with Customer, Contract Liability [Roll Forward]
Beginning balance	$ 13,466
Additions to sales incentive accrual	22,078
Contract payments	(21,677)
Foreign currency fluctuations	(239)
Ending balance	$ 13,628

Amount of liability for consideration received or receivable from customer which is not included in transaction price, when consideration is expected to be refunded to customer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 55
-Paragraph 25
-URI http://asc.fasb.org/extlink&oid=96862333&loc=SL49130609-203046-203046

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 55
-Paragraph 23
-URI http://asc.fasb.org/extlink&oid=96862333&loc=SL49130607-203046-203046

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 32
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=82859839&loc=SL51751984-203043

Name:	us-gaap_ContractWithCustomerRefundLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant