Revenues Revenues - Revenue recognized (Details) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($)
Revenue from Contract with Customer [Abstract]
Revenue recognized that was included in the contract liability balance at the beginning of the period	$ (14,716)
Increases due to cash received, excluding amounts recognized as revenue during the period	$ 12,374

Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130549-203045

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