INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES - Summary of Financial Position of Real Estate Ventures (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Real Estate Investment Property, Net	$ 2,966,005	$ 3,371,231
Other assets	176,747	115,678
Other liabilities	47,573	15,985
Outstanding indebtedness	1,830,595	2,144,418
Equity	1,804,648	1,688,303	$ 1,811,028	$ 1,826,870
Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Real Estate Investment Property, Net	1,520,804	834,367
Other assets	488,805	342,002
Other liabilities	333,049	290,071
Outstanding indebtedness	956,688	585,068
Equity	$ 719,872	$ 301,230