Segment Reporting - Summary of Financial Results by Segment (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019
Revenues:
Total revenues	$ 76,920	$ 24,026				$ 205,422	$ 58,184
Expenses
Operating expenses	29,504	10,855				77,167	26,889
Income (loss) from real estate-related securities, net	11,068	3,323				(27)	6,868
Loss from unconsolidated real estate ventures	(666)	(233)				(887)	(46)
Segment net operating income	57,818	16,261				127,341	38,117
Depreciation and amortization	(38,543)	(8,444)				(107,993)	(20,852)
General and administrative	(2,023)	(1,076)				(6,163)	(2,877)
Management fees	(5,018)	(1,713)			$ (2,800)	(13,560)	(2,793)
Performance participation allocation	0	(2,286)				(46)	(5,501)
Interest expense	(22,539)	(6,153)				(65,448)	(15,625)
Other expense, net	(192)					(29)
Net loss	(10,497)	(3,076)	$ (3,596)	$ (2,468)		(65,898)	(9,142)
Net loss attributable to non-controlling interests in consolidated joint ventures	139	25				1,186	43
Net loss attributable to non-controlling interests in Operating Partnership	43					458
Net loss attributable to stockholders	(10,315)	(3,051)				(64,254)	(9,099)
Other income, net		335					389
Rental
Revenues:
Total revenues	71,896	13,184				186,688	25,154
Expenses
Operating expenses	25,915	4,724				64,873	9,219
Hotel Revenue / Expenses
Revenues:
Total revenues	4,420	10,238				17,134	31,380
Expenses
Operating expenses	3,589	6,131				12,294	17,670
Other revenue
Revenues:
Total revenues	604	604				1,600	1,650
Operating Segments | Multifamily
Revenues:
Total revenues	33,422	6,435				89,042	16,173
Expenses
Operating expenses	13,186	2,483				33,457	6,062
Segment net operating income	20,236	3,952				55,585	10,111
Depreciation and amortization	(15,702)	(2,297)				(49,826)	(8,493)
Operating Segments | Hotel
Revenues:
Total revenues	4,433	10,333				17,225	31,562
Expenses
Operating expenses	3,589	6,131				12,294	17,670
Loss from unconsolidated real estate ventures	(666)	(233)				(887)	(46)
Segment net operating income	178	3,969				4,044	13,846
Depreciation and amortization	(2,142)	(2,065)				(6,284)	(6,173)
Operating Segments | Industrial
Revenues:
Total revenues	7,027					20,415
Expenses
Operating expenses	1,641					5,003
Segment net operating income	5,386					15,412
Depreciation and amortization	(4,161)					(12,489)
Operating Segments | Office
Revenues:
Total revenues	28,054	7,258				68,880	10,449
Expenses
Operating expenses	9,644	2,241				23,059	3,157
Segment net operating income	18,410	5,017				45,821	7,292
Depreciation and amortization	(14,214)	(4,082)				(34,319)	(6,186)
Operating Segments | Real Estate-Related Securities
Expenses
Income (loss) from real estate-related securities, net	11,068	3,323				(27)	6,868
Segment net operating income	11,068	3,323				(27)	6,868
Operating Segments | Medical Office
Revenues:
Total revenues	3,984					9,860
Expenses
Operating expenses	1,444					3,354
Segment net operating income	2,540					6,506
Depreciation and amortization	(2,324)					(5,075)
Operating Segments | Rental | Multifamily
Revenues:
Total revenues	32,891	5,937				87,666	14,725
Expenses
Operating expenses	13,186	2,483				33,457	6,062
Operating Segments | Rental | Industrial
Revenues:
Total revenues	7,027					20,415
Expenses
Operating expenses	1,641					5,003
Operating Segments | Rental | Office
Revenues:
Total revenues	28,005	7,247				68,777	10,429
Expenses
Operating expenses	9,644	2,241				23,059	3,157
Operating Segments | Rental | Medical Office
Revenues:
Total revenues	3,973					9,830
Expenses
Operating expenses	1,444					3,354
Operating Segments | Hotel Revenue / Expenses | Hotel
Revenues:
Total revenues	4,420	10,238				17,134	31,380
Expenses
Operating expenses	3,589	6,131				12,294	17,670
Operating Segments | Other revenue | Multifamily
Revenues:
Total revenues	531	498				1,376	1,448
Operating Segments | Other revenue | Hotel
Revenues:
Total revenues	13	95				91	182
Operating Segments | Other revenue | Office
Revenues:
Total revenues	49	$ 11				103	$ 20
Operating Segments | Other revenue | Medical Office
Revenues:
Total revenues	$ 11					$ 30