ORGANIZATION - Narrative (Details)	3 Months Ended	12 Months Ended
Mar. 31, 2019	Dec. 31, 2018
AXA Equity Holdings [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership percentage	48.00%	59.00%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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