SIGNIFICANT ACCOUNTING POLICIES (Details 4)	12 Months Ended
	Dec. 31, 2019 USD ($) a Integer	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Property, Plant and Equipment [Line Items]
Number of Reportable Segments | Integer	1
Length of Time After Project Completion When Development Cost Ceased Being Capitalized	1 year
Development properties [Member]
Property, Plant and Equipment [Line Items]
Percentage of Occupation when property transfers from the development and value-add program to real estate properties	90.00%
Length of Time After Project Acquisition (for Value-add) or Shell Completion (for Developments) When Project Transfers to Real Estate Properties	1 year
Value-add properties [Member]
Property, Plant and Equipment [Line Items]
Percentage of Occupation when property transfers from the development and value-add program to real estate properties	90.00%
Length of Time After Project Acquisition (for Value-add) or Shell Completion (for Developments) When Project Transfers to Real Estate Properties	1 year
Development and value-add properties [Member]
Property, Plant and Equipment [Line Items]
Length of Time After Project Completion When Development Cost Ceased Being Capitalized	1 year
Percentage of Occupation When Development & Value-add Cost Ceased Being Capitalized	90.00%
Otay Mesa Land | Real Estate Properties [Domain]
Property, Plant and Equipment [Line Items]
Size (in acres) of land acquired | a	41.6
Total cost of properties purchased	$ 15,282,000
Miramar Land [Member] | Below market lease [Member]
Property, Plant and Equipment [Line Items]
Intangibles acquired associated with purchase of Real Estate	$ 593,000
Miramar Land [Member] | Real Estate Properties [Domain]
Property, Plant and Equipment [Line Items]
Size (in acres) of land acquired | a	6.5
Total cost of properties purchased	$ 13,386,000
Book value of land based on third party valuations	$ 13,979,000
Yosemite Land | Real Estate Properties [Domain]
Property, Plant and Equipment [Line Items]
Size (in acres) of land acquired | a	0.5
Total cost of properties purchased	$ 472,000
2019 Acquisitions [Member]
Property, Plant and Equipment [Line Items]
Total cost of properties purchased	205,841,000
2019 Acquisitions [Member] | Above Market Leases [Member]
Property, Plant and Equipment [Line Items]
Intangibles acquired associated with purchase of Real Estate	344,000
2019 Acquisitions [Member] | Leases, Acquired-in-Place [Member]
Property, Plant and Equipment [Line Items]
Intangibles acquired associated with purchase of Real Estate	10,020,000
2019 Acquisitions [Member] | Below market lease [Member]
Property, Plant and Equipment [Line Items]
Intangibles acquired associated with purchase of Real Estate	2,092,000
2019 Acquisitions [Member] | Development and value-add properties [Member]
Property, Plant and Equipment [Line Items]
Total amount allocated to real estate properties	92,268,000
2019 Acquisitions [Member] | Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Total purchase price allocated to land	46,778,000
2019 Acquisitions [Member] | Real estate properties [Member]
Property, Plant and Equipment [Line Items]
Total amount allocated to real estate properties	$ 105,301,000
2018 Acquisitions [Member]
Property, Plant and Equipment [Line Items]
Total cost of properties purchased		$ 71,086,000
2018 Acquisitions [Member] | Above Market Leases [Member]
Property, Plant and Equipment [Line Items]
Intangibles acquired associated with purchase of Real Estate		21,000
2018 Acquisitions [Member] | Leases, Acquired-in-Place [Member]
Property, Plant and Equipment [Line Items]
Intangibles acquired associated with purchase of Real Estate		4,350,000
2018 Acquisitions [Member] | Below market lease [Member]
Property, Plant and Equipment [Line Items]
Intangibles acquired associated with purchase of Real Estate		1,756,000
2018 Acquisitions [Member] | Development and value-add properties [Member]
Property, Plant and Equipment [Line Items]
Total amount allocated to real estate properties		13,934,000
2018 Acquisitions [Member] | Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Total purchase price allocated to land		23,263,000
2018 Acquisitions [Member] | Real Estate Properties [Domain]
Property, Plant and Equipment [Line Items]
Total amount allocated to real estate properties		$ 54,537,000
2017 Acquisitions
Property, Plant and Equipment [Line Items]
Total cost of properties purchased			$ 65,243,000
2017 Acquisitions | Above Market Leases [Member]
Property, Plant and Equipment [Line Items]
Intangibles acquired associated with purchase of Real Estate			115,000
2017 Acquisitions | Leases, Acquired-in-Place [Member]
Property, Plant and Equipment [Line Items]
Intangibles acquired associated with purchase of Real Estate			3,662,000
2017 Acquisitions | Below market lease [Member]
Property, Plant and Equipment [Line Items]
Intangibles acquired associated with purchase of Real Estate			385,000
2017 Acquisitions | Development and value-add properties [Member]
Property, Plant and Equipment [Line Items]
Total amount allocated to real estate properties			10,312,000
2017 Acquisitions | Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Total purchase price allocated to land			11,281,000
2017 Acquisitions | Real estate properties [Member]
Property, Plant and Equipment [Line Items]
Total amount allocated to real estate properties			$ 51,539,000