BUSINESS ACQUISITION - Fair value of contingent consideration (Details) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) item
Business Acquisition [Line Items]
Fair value change in contingent consideration	$ (65,594)	$ 30,460
Acquisition in 2018
Business Acquisition [Line Items]
Number of acquisition completed \| item		3
Fair value change in contingent consideration		$ 49,503

Amount of increase (decrease) in the value of a contingent consideration liability, including, but not limited to, differences arising upon settlement.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=120321790&loc=d3e7008-128479

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration