EQUITY AND EARNINGS PER SHARE - Outstanding Options (Details) - shares	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)	8,498,138
Held by the Manager
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)	6,961,222	16,387,480
Issued to the Manager and subsequently assigned to certain of the Manager’s employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)	1,530,916	2,108,708
Issued to the independent directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)	6,000	6,000
Total
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding (in shares)	8,498,138	18,502,188