SIGNIFICANT ACCOUNTING POLICIES (Details 4)	9 Months Ended	12 Months Ended
	Sep. 30, 2016 Integer	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Acquired Finite-Lived Intangible Assets [Line Items]
Above and below market leases Increase (decrease) rental Income		$ 488,000	$ 448,000	$ 421,000
Amortization expense for in-place lease intangibles		4,210,000	4,370,000	4,727,000
Projected amortization of in-place lease intangibles for the next five years [Abstract]
2017		3,572,000
2018		2,545,000
2019		2,042,000
2020		1,551,000
2021		1,150,000
Flagler Center [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Number of buildings | Integer	3
2016 Acquisitions (Parc North, Flagler, Weston and Jones) [Member]
Acquired operating properties [Abstract]
Total cost of properties purchased		112,158,000
Total purchase price to land		29,164,000
2016 Acquisitions (Parc North, Flagler, Weston and Jones) [Member] | Above Market Leases [Member]
Acquired operating properties [Abstract]
Intangibles acquired associated with purchase of Real Estate		393,000
2016 Acquisitions (Parc North, Flagler, Weston and Jones) [Member] | Leases, Acquired-in-Place [Member]
Acquired operating properties [Abstract]
Intangibles acquired associated with purchase of Real Estate		5,941,000
2016 Acquisitions (Parc North, Flagler, Weston and Jones) [Member] | Below market lease [Member]
Acquired operating properties [Abstract]
Intangibles acquired associated with purchase of Real Estate		894,000
Southpark Corporate Center and Springdale Business Center [Member]
Acquired operating properties [Abstract]
Total cost of properties purchased			31,574,000
Total purchase price to land			5,494,000
Southpark Corporate Center and Springdale Business Center [Member] | Leases, Acquired-in-Place [Member]
Acquired operating properties [Abstract]
Intangibles acquired associated with purchase of Real Estate			3,453,000
Southpark Corporate Center and Springdale Business Center [Member] | Below market lease [Member]
Acquired operating properties [Abstract]
Intangibles acquired associated with purchase of Real Estate			527,000
Ridge Creek Distribution Center III, Colorado Crossing Distribution Center and Ramona Distribution Center [Domain]
Acquired operating properties [Abstract]
Total cost of properties purchased				51,652,000
Total amount allocated to real estate properties				47,477,000
Total purchase price to land				10,822,000
Cash paid for acquired properties				48,805,000
Mortgages assumed in connection with purchase of real estate, face amount				2,617,000
Premium on mortgage loan, amount recognized at assumption of loan				230,000
Ridge Creek Distribution Center III, Colorado Crossing Distribution Center and Ramona Distribution Center [Domain] | Above Market Leases [Member]
Acquired operating properties [Abstract]
Intangibles acquired associated with purchase of Real Estate				4,000
Ridge Creek Distribution Center III, Colorado Crossing Distribution Center and Ramona Distribution Center [Domain] | Leases, Acquired-in-Place [Member]
Acquired operating properties [Abstract]
Intangibles acquired associated with purchase of Real Estate				5,074,000
Ridge Creek Distribution Center III, Colorado Crossing Distribution Center and Ramona Distribution Center [Domain] | Below market lease [Member]
Acquired operating properties [Abstract]
Intangibles acquired associated with purchase of Real Estate				$ 903,000
Real Estate Properties [Domain] | 2016 Acquisitions (Parc North, Flagler, Weston and Jones) [Member]
Acquired operating properties [Abstract]
Total amount allocated to real estate properties		22,228,000
Real Estate Properties [Domain] | Southpark Corporate Center and Springdale Business Center [Member]
Acquired operating properties [Abstract]
Total amount allocated to real estate properties			$ 28,648,000
Industrial Development [Member] | 2016 Acquisitions (Parc North, Flagler, Weston and Jones) [Member]
Acquired operating properties [Abstract]
Total amount allocated to real estate properties		$ 84,490,000