REAL ESTATE PROPERTIES 4 (Details)		12 Months Ended
		Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jun. 30, 2019 USD ($)	Jan. 01, 2019 USD ($)
Ground Lease Details
Payments to Develop Real Estate Assets		$ 318,288,000	$ 167,667,000	$ 124,938,000
Operating Lease, Right-of-Use Asset	[1]	11,997,000	0
Operating lease, Right-of-Use Asset, net of amortization		$ 11,997,000
Weighted Average term for ground leases		43 years
Leases terms minimum (in years)		40 years
Leases terms maximum (in years)		50 years
Lease Expiration Date		August 2031
Ground lease expiration date, furthest date		October 2058
Renewal period option minimum (in years)		15 years
Renewal period option maximum (in years)		35 years
Total ground lease expenditures for continuing and discontinued operations		$ 966,000	783,000	$ 760,000
Payment increase interval maximum		10 years
Payment increase interval minimum (in years)		3 years
Future Total Minimum Ground Lease Payments [Abstract]
Payments Due, Next Twelve Months		$ 970,000	791,000
Payments Due in Two Years		970,000	791,000
Payments Due in Three Years		970,000	791,000
Payments Due in Four Years		975,000	791,000
Payments Due in Five Years		999,000	791,000
Thereafter		38,916,000	30,751,000
Total minimum payments		43,800,000	$ 34,706,000
imputed interest related to right of use assets for ground leases	[2]	(31,752,000)
Total ground leases		$ 12,048,000
Incremental borrowing rate used in determining the present value of lease payments						7.30%
ARIZONA
Ground Lease Details
Number of properties subject to ground leases		1
TEXAS
Ground Lease Details
Number of properties subject to ground leases		3
FLORIDA
Ground Lease Details
Number of properties subject to ground leases		2
Logistics Center 6 & 7 [Member]
Future Total Minimum Ground Lease Payments [Abstract]
Incremental borrowing rate used in determining the present value of lease payments					8.00%
Accounting Standards Update 2016-02 [Member]
Ground Lease Details
Operating Lease, Right-of-Use Asset						$ 10,226,000
Operating lease, Right-of-Use Asset, net of amortization		$ 11,997,000
Accounting Standards Update 2016-02 [Member] | Logistics Center 6 & 7 [Member]
Ground Lease Details
Operating Lease, Right-of-Use Asset					$ 2,679,000
Development completed and transferred to Real estate properties [Member]
Ground Lease Details
Payments to Develop Real Estate Assets		$ 47,415,000

[1] See Ground Leases discussion below and in Note 1(o) for information regarding the Company's right of use assets for ground leases.

[2] 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%.