Real Estate Assets - Purchase Price Allocation (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Business Acquisition
Tenant Improvements	$ 175,400,000		$ 175,400,000		$ 167,275,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	24,000		24,000
Net assets acquired		$ 90,664,000		$ 90,664,000
Satisfaction of loan receivables				46,397,000
Total consideration				90,664,000
Revenues	126,697,000	120,203,000	381,076,000	345,561,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	26,746,000	26,086,000	(102,321,000)	75,093,000
Business Acquisition, Transaction Costs		1,016,000		1,016,000
Business Combination, Acquisition Related Costs Paid To Related Party				936,000
Multifamily Acquisitions [Member]
Business Acquisition
Land	12,945,000		12,945,000
Buildings and improvements	100,113,000		100,113,000
Furniture, fixtures and equipment	26,284,000		26,284,000
Lease intangibles			5,968,000
Accrued taxes	(437,000)		(437,000)
Security deposits, prepaid rents, and other liabilities	(384,000)		(384,000)
Cash paid			45,037,000
Total consideration			144,513,000
Revenues	2,883,000		5,258,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(1,832,000)		(4,018,000)
capitalized acquisition costs asset acquisition			$ 4,085,000
Finite-Lived Intangible Assets, Remaining Amortization Period			11 years 6 months
business combination debt financing			$ 99,476,000
Business Acquisition, Transaction Costs	0		0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	144,513,000		144,513,000
Q2 2018 NMP acquisitions [Domain]
Business Acquisition
Land	9,328,000	57,916,000	9,328,000	57,916,000
Buildings and improvements	12,264,000	101,873,000	12,264,000	101,873,000
Tenant Improvements	2,099,000	8,230,000	2,099,000	8,230,000
Finite-Lived Intangible Asset, Acquired-in-Place Leases	3,043,000	16,080,000	3,043,000	16,080,000
Finite-Lived Intangible Asset, Off-market Lease, Favorable, Gross	107,000	2,759,000	107,000	2,759,000
Other Finite-Lived Intangible Assets, Gross	1,237,000	5,768,000	1,237,000	5,768,000
Off-market Lease, Unfavorable	(359,000)	(10,537,000)	(359,000)	(10,537,000)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	61,000	98,000	61,000	98,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities	(249,000)	(748,000)	(249,000)	(748,000)
Cash paid			7,891,000	115,913,000
Total consideration			27,531,000	181,439,000
Revenues	678,000	3,976,000	1,723,000	13,094,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	5,000	(997,000)	59,000	(2,126,000)
capitalized acquisition costs asset acquisition			$ 470,000	$ 4,022,000
Finite-Lived Intangible Assets, Remaining Amortization Period			10 years 2 months 12 days	8 years
business combination debt financing			$ 19,640,000	$ 65,526,000
Business Acquisition, Transaction Costs	249,000	1,799,000	249,000	1,799,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	27,531,000	181,439,000	27,531,000	181,439,000
westridge [Member]
Business Acquisition
Land		7,289,000		7,289,000
Buildings and improvements		68,163,000		68,163,000
Furniture, fixtures and equipment		16,966,000		16,966,000
Lease intangibles				983,000
Accrued taxes		(158,000)		(158,000)
Security deposits, prepaid rents, and other liabilities		$ (2,579,000)		(2,579,000)
Cash paid				2,717,000
Mortgage debt, net				$ 41,550,000
Revenues	2,042,000		5,980,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 36,000		$ 307,000
Finite-Lived Intangible Assets, Remaining Amortization Period				0 years