REAL ESTATE SOLD AND HELD FOR SALE DISCONTINUED OPERATIONS (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($) ft² a Integer
2019 Operating Property Sales [Member] [Domain]
Long Lived Assets Held-for-sale [Line Items]
Number of real estate properties transferred to held for sale and sold | Integer		5
Square Footage of Real Estate Property | ft²		617,000
Proceeds from Sale of Property, Plant, and Equipment		$ 68,500,000
Gain (Loss) on Sale of Properties		41,100,000
Land [Member]
Long Lived Assets Held-for-sale [Line Items]
Proceeds from Sale of Property, Plant, and Equipment		$ 185,000
Size (in acres) of land sold | a		0.2
Gain on sales of land		$ 83,000
World Houston International Business Ctr 5 [Member]
Long Lived Assets Held-for-sale [Line Items]
Proceeds from Sale of Property, Plant, and Equipment	$ 2,325,000