REAL ESTATE AND RELATED LEASE INTANGIBLES, NET - Schedule of Real Estate Properties Acquired (Details) - USD ($) $ in Thousands	1 Months Ended						5 Months Ended	6 Months Ended
	Jun. 30, 2019	Apr. 30, 2019	Feb. 28, 2019	May 31, 2018	Apr. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2019	Jun. 30, 2018
Business Acquisition [Line Items]
Purchase Price							$ 5,071	$ 23,271	$ 115,548
Real estate acquired through foreclosure	$ 18,200						$ 18,200	$ 18,200
Lithia Springs, GA | Diversified
Business Acquisition [Line Items]
Purchase Price						$ 24,466
Ownership Interest									70.60%
Lithia Springs, GA | Diversified | Corporate Joint Venture
Business Acquisition [Line Items]
Purchase Price									$ 2,900
Kirbyville, MO | Net Lease
Business Acquisition [Line Items]
Purchase Price					$ 1,156
Ownership Interest									100.00%
Gladwin, MI | Net Lease
Business Acquisition [Line Items]
Purchase Price					1,171
Ownership Interest									100.00%
Foley, MN | Net Lease
Business Acquisition [Line Items]
Purchase Price					1,176
Ownership Interest									100.00%
Moscow Mills, MO | Net Lease
Business Acquisition [Line Items]
Purchase Price					1,237
Ownership Interest									100.00%
Wonder Lake, IL | Net Lease
Business Acquisition [Line Items]
Purchase Price					$ 1,255
Ownership Interest									100.00%
Isla Vista, CA | Diversified
Business Acquisition [Line Items]
Purchase Price				$ 85,087
Ownership Interest									75.00%
Isla Vista, CA | Diversified | Corporate Joint Venture
Business Acquisition [Line Items]
Purchase Price									$ 4,600
Houghton Lake, Michigan
Business Acquisition [Line Items]
Purchase Price			$ 1,242
Ownership Interest	100.00%						100.00%	100.00%
Trenton, Missouri
Business Acquisition [Line Items]
Purchase Price			1,164
Ownership Interest	100.00%						100.00%	100.00%
Centralia, Illinois
Business Acquisition [Line Items]
Purchase Price		$ 1,242
Ownership Interest	100.00%						100.00%	100.00%
Fayette, Missouri
Business Acquisition [Line Items]
Purchase Price	$ 1,423
Ownership Interest	100.00%						100.00%	100.00%
Omaha, Nebraska
Business Acquisition [Line Items]
Ownership Interest	100.00%						100.00%	100.00%
Omaha, Nebraska | Real Estate Acquired in Satisfaction of Debt
Business Acquisition [Line Items]
Real estate acquired through foreclosure	$ 18,200		$ 18,200				$ 18,200	$ 18,200