REVENUE - Deferred Merchant Bookings (Details)	6 Months Ended
Jun. 30, 2022
Online travel reservation services
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Revenue, performance obligation, description of timing	one year

Description of timing for satisfying performance obligation in contract with customer. Includes, but is not limited to, as services are rendered, and upon shipment, delivery or completion of service.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

Name:	us-gaap_RevenuePerformanceObligationDescriptionOfTiming
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration