INCOME PROPERTY PORTFOLIO - General Information (Details) ft² in Millions	3 Months Ended
	Mar. 31, 2020 USD ($) ft² property	Mar. 31, 2019 property
Acquisitions of Income Properties
Number of real estate properties | property	29
Area of real estate property | ft²	1.1
Number of properties sold	0	0
Amount allocated of total acquisition cost
Weighted average amortization period of intangible assets	9 years
Weighted average amortization period of intangible liabilities	9 years
2020 acquisitions of income property subject to lease
Acquisitions of Income Properties
Number of real estate properties	9
Payments to Acquire Commercial Real Estate	$ 46,800,000
Aggregate acquisition cost including capitalized acquisition costs	47,000,000
Land	11,900,000
Buildings and improvements	29,300,000
Intangible assets pertaining to the in-place lease value, leasing fees and above market lease value	6,900,000
Intangible liabilities for below market lease value	$ 1,100,000
Amount allocated of total acquisition cost
Weighted average amortization period of intangible liabilities	11 years 2 months 12 days