Revenue Recognition - Contract Acquisition Costs (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019
Increase (Decrease) In Capitalized Contract Cost [Roll Forward]
Balance at beginning of period	$ 113,592	$ 114,306
Additions	68,589	71,651
Amortization expense	(75,429)	(72,412)
Foreign currency translation	(2,984)	(1,012)
Balance at end of period	$ 103,768	$ 112,533

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-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