REAL ESTATE PROPERTIES - Ground Leases (Details)		12 Months Ended
		Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jan. 01, 2019 USD ($)
Ground Lease [Line Items]
Operating Lease, Right-of-Use Asset		$ 11,073,000	$ 11,997,000
Total ground lease expenditures for continuing and discontinued operations		$ 1,051,000	$ 966,000	$ 783,000
Incremental borrowing rate used in determining the present value of lease payments					8.00%	7.30%
Ground leases [Member]
Ground Lease [Line Items]
Leases terms minimum		40 years
Leases terms maximum		50 years
Lease Expiration Date		August 2031
Ground lease expiration date, furthest date		October 2058
Renewal period option minimum		15 years
Renewal period option maximum		35 years
Payment increase interval minimum		3 years
Payment increase interval maximum		10 years
Weighted Average term for ground leases		42 years
Operating Leases, Future Minimum Payments Due, Next Twelve Months		$ 970,000
Operating Leases, Future Minimum Payments, Due in Two Years		970,000
Operating Leases, Future Minimum Payments, Due in Three Years		975,000
Operating Leases, Future Minimum Payments, Due in Four Years		999,000
Operating Leases, Future Minimum Payments, Due in Five Years		999,000
Operating leases, future minimum payments due, Thereafter		37,917,000
Operating leases, future minimum payments due, Total		42,830,000
imputed interest related to right of use assets for ground leases	[1]	(31,631,000)
Operating Leases, Future Minimum Payments Due		$ 11,199,000
FLORIDA
Ground Lease [Line Items]
Properties subject to ground leases		2
TEXAS
Ground Lease [Line Items]
Properties subject to ground leases		3
ARIZONA
Ground Lease [Line Items]
Properties subject to ground leases		1
Accounting Standards Update 2016-02 [Member] | Ground leases [Member]
Ground Lease [Line Items]
Operating Lease, Right-of-Use Asset						$ 10,226,000
Accounting Standards Update 2016-02 [Member] | Logistics Center 6 & 7 [Member]
Ground Lease [Line Items]
Operating Lease, Right-of-Use Asset					$ 2,679,000

[1] As the Company’s leases do not provide an implicit rate, in order to calculate the present value of the remaining ground lease payments, the Company used its incremental borrowing rate, adjusted for a number of factors, including the long-term nature of the ground leases, the Company’s estimated borrowing costs, and the estimated fair value of the underlying land, to determine the imputed interest for its ground leases. The Company elected to use the portfolio approach as all of its ground leases in place as of January 1, 2019, have similar characteristics and determined 7.3% as the appropriate rate as of January 1, 2019, for all leases in place at that time. For the ground lease obtained during April 2019, the Company used its incremental borrowing rate, adjusted for the factors discussed above, which was determined to be 8.0%.