Revenue and Related Contract Costs and Contract Liabilities - Summary of Changes in Contract Costs (Details) $ in Thousands	3 Months Ended
Mar. 31, 2019 USD ($)
Revenue From Contract With Customer [Abstract]
Balance at December 31, 2018	$ 21,478
Additions	18,484
Expenses	(13,295)
Cancelled	(3)
Foreign exchange translation adjustment	92
Balance at March 31, 2019	$ 26,756

Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=68051541&loc=SL49131252-203054

Name:	us-gaap_CapitalizedContractCostNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant