INVESTMENTS - Equity Method (Details) $ in Millions	3 Months Ended
Mar. 31, 2020 USD ($) item	Mar. 31, 2019 USD ($)	Dec. 31, 2019 item
INVESTMENTS
Number of entity's investments which is accounted for using equity method \| item	3		3
Cash distributions received from partnerships treated as equity method investees \| $	$ 4.8	$ 4.0

Amount of distribution received from equity method investee for return of investment, classified as investing activities. Excludes distribution for return on investment, classified as operating activities.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 21D
-URI http://asc.fasb.org/extlink&oid=118932676&loc=SL94080555-108585

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3179-108585

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