Real Estate Assets - Narrative (Details)				3 Months Ended			9 Months Ended
	Jul. 15, 2020 USD ($)	Mar. 20, 2020 USD ($) number_of_properties	Mar. 06, 2020 USD ($)	Sep. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Sep. 30, 2019 USD ($) bed number_of_properties	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($) bed number_of_properties	Sep. 30, 2020	Sep. 30, 2020 ft²	Dec. 31, 2019 USD ($)
Business Acquisition
Total consideration								$ 90,664,000
Number of units in real estate property									12,936	680	12,256
purchase option termination fees received		$ 2,750,000	$ 2,500,000		$ 9,100,000
Intangible Assets, Gross (Excluding Goodwill)				$ 310,600,000			$ 310,600,000
Finite-Lived Intangible Assets, Accumulated Amortization				177,348,000			177,348,000				$ 149,896,000
Finite-Lived Intangible Liabilities							86,000,000.0
finite lived intangible liabilities accumulated amortization							31,500,000
Restricted Cash				18,800,000			18,800,000
amortization of purchase option termination fee income				421,000		$ 1,283,000	4,896,000	6,900,000
Contract with Customer, Liability				$ 800,000			800,000
Contract With Customer, Liability, Percent Of Total Rental And Other Revenue				0.70%
Bad Debt Expense Related To COVID-19				$ 1,700,000
Bad Debt Expense Related To COVID-19, Percentage Of Rental And Other Revenues				1.40%
Business Acquisition, Number Of Properties Failure to Consummate Purchase | number_of_properties		6
Joint Venture
Business Acquisition
Payments to Acquire Real Estate and Real Estate Joint Ventures	$ 19,200,000
Gain (Loss) from Transactions With Joint Ventures	$ 3,300,000
Ownership Interest in Joint Ventures	50.00%
Future Capital Expenditures [Member]
Business Acquisition
Restricted Cash				$ 33,600,000			33,600,000
Other Property Level Commitments [Member]
Business Acquisition
Restricted Cash				$ 6,800,000			6,800,000
sanibel straights [Member]
Business Acquisition
amortization of purchase option termination fee income							$ 4,900,000	$ 6,900,000
Minimum [Member]
Business Acquisition
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life							7 years 2 months 12 days
Maximum [Member]
Business Acquisition
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life							8 years 8 months 12 days
Multifamily Communities
Business Acquisition
Total consideration							$ 141,200,000
Haven49 [Member]
Business Acquisition
Number of units in real estate property | number_of_properties						322		322
Number Of Beds In Real Estate Property | bed						887		887
New Market Properties [Member]
Business Acquisition
Total consideration							$ 27,700,000	$ 178,500,000