Real Estate Assets - Narrative (Details)			3 Months Ended								12 Months Ended
	Dec. 09, 2019 USD ($)	Jun. 28, 2019 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) ft²	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) ft²	Dec. 31, 2017 USD ($)	Dec. 31, 2019 ft²	Dec. 31, 2019	Dec. 31, 2019 number_of_properties
Business Acquisition
Revenue From Forfeited Earnest Deposit	$ 1,000,000	$ 1,000,000
Restricted Cash, Nature of Restriction, Description											18.7
purchase option termination fees received											$ 8,400,000
unearned revenue from purchase option termination fees			$ 2,859,000				$ 2,050,000				2,859,000	$ 2,050,000
Intangible Assets, Gross (Excluding Goodwill)							$ 304,700,000					$ 304,700,000
Number of Real Estate Properties							19					19			19	123
Number of units in real estate property | ft²							1,347					1,347		477
Revenues			124,866,000	$ 120,203,000	$ 113,852,000	$ 111,506,000	$ 106,280,000	$ 104,232,000	$ 96,389,000	$ 90,370,000	470,427,000	$ 397,271,000	$ 294,005,000
Net Income contributed to consolidated results			(1,364,000)	$ (2,137,000)	$ (1,677,000)	$ (2,280,000)	27,199,000	$ 8,354,000	$ (5,278,000)	$ 14,263,000	(7,458,000)	44,538,000	28,667,000
Gains (Losses) on Sales of Investment Real Estate											1,567,000	69,705,000	37,635,000
Income (Loss) before Gain (Loss) on Sale of Properties											100,238,000	70,077,000	59,388,000
Finite-Lived Intangible Assets, Accumulated Amortization			$ 149,896,000				$ 113,199,000				149,896,000	113,199,000
Finite-Lived Intangible Liabilities											86,300,000
finite lived intangible liabilities accumulated amortization											23,700,000
amortization of purchase option termination fee income											9,111,000	9,820,000	$ 0
New Market Properties [Member]
Business Acquisition
Net assets acquired											92,400,000	$ 197,000,000
Area of Real Estate Property | ft²							674,981					674,981		1,318,519
Retail Site [Member]
Business Acquisition
Number of Real Estate Properties							45					45			52
Area of Real Estate Property | ft²							4,730,695					4,730,695		6,041,629
Wiregrass [Domain]
Business Acquisition
amortization of purchase option termination fee income											5,500,000
haven charlotte [Member]
Business Acquisition
amortization of purchase option termination fee income net											3,600,000
Lake Cameron [Member]
Business Acquisition
Number of units in real estate property															328
Net assets acquired											43,500,000
Gains (Losses) on Sales of Investment Real Estate											20,400,000
Income (Loss) before Gain (Loss) on Sale of Properties											$ 200,000