REAL ESTATE SOLD AND HELD FOR SALE DISCONTINUED OPERATIONS (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2019 USD ($) ft²	Mar. 31, 2018 USD ($) a	Dec. 31, 2018 USD ($) ft² Integer
Long Lived Assets Held-for-sale [Line Items]
Document Period End Date	Mar. 31, 2019
Gains (Losses) on Sales of Investment Real Estate	$ 2,325,000	$ 10,222,000
Number of real estate properties transferred to held for sale and sold | Integer			3
2019 Operating Property Sales [Member] [Domain]
Long Lived Assets Held-for-sale [Line Items]
Square Footage of Real Estate Property | ft²	51,000
Gain (Loss) on Sale of Properties	$ 2,300,000
Proceeds from Sale of Property, Plant, and Equipment	$ 3,800,000
2018 Operating Property Sales [Member]
Long Lived Assets Held-for-sale [Line Items]
Square Footage of Real Estate Property | ft²			339,000
Gain (Loss) on Sale of Properties			$ 14,300,000
Proceeds from Sale of Property, Plant, and Equipment			$ 22,900,000
Land [Member]
Long Lived Assets Held-for-sale [Line Items]
SIze (in acres) of land sold | a		11
Proceeds from Sale of Property, Plant, and Equipment		$ 2,600,000
Gain on sales of land		$ 86,000