Equity Investments, at Fair Value - Schedule of Income From Multi-Family Preferred Equity Ownership Interests (Details) - Multi-Family Preferred Equity Ownership Interests - Equity investments - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	$ 5,775	$ 5,499
Somerset Deerfield Investor, LLC
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	587	466
RS SWD Owner, LLC, RS SWD Mitchell Owner, LLC, RS SWD IF Owner, LLC, RS SWD Mullis Owner, LLC, RS SWD JH Mullis Owner, LLC and RS SWD Saltzman Owner, LLC (collectively)
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	159	124
Walnut Creek Properties Holdings, L.L.C.
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	(153)	277
DCP Gold Creek, LLC
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	853	202
1122 Chicago DE, LLC
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	237	221
Rigsbee Ave Holdings, LLC
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	(174)	320
Bighaus, LLC
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	465	436
FF/RMI 20 Midtown, LLC
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	798	746
Lurin-RMI, LLC
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	280	236
Palms at Cape Coral, LLC
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	155	0
America Walks at Port St. Lucie, LLC
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	902	0
EHOF-NYMT Sunset Apartments Preferred, LLC
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	549	0
Lucie at Tradition Holdings, LLC
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	601	0
Syracuse Apartments and Townhomes, LLC
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	516	0
BBA-EP320 II, L.L.C., BBA-Ten10 II, L.L.C., and Lexington on the Green Apartments, L.L.C. (collectively)
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	0	347
Audubon Mezzanine Holdings, L.L.C. (Series A)
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	0	364
EP 320 Growth Fund, L.L.C. (Series A) and Turnbury Park Apartments - BC, L.L.C. (Series A) (collectively)
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	0	179
Towers Property Holdings, LLC
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	0	379
Mansions Property Holdings, LLC
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	0	365
Sabina Montgomery Holdings, LLC - Series B and Oakley Shoals Apartments, LLC - Series A (collectively)
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	0	135
Gen1814, LLC - Series A, Highlands - Mtg. Holdings, LLC - Series A, and Polos at Hudson Investments, LLC - Series A (collectively)
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	0	314
Axis Apartments Holdings, LLC, Arbor-Stratford Holdings II, LLC - Series B, Highlands - Mtg. Holdings, LLC - Series B, Oakley Shoals Apartments, LLC - Series C, and Woodland Park Apartments II, LLC (collectively)
Schedule of Equity Method Investments [Line Items]
Change in fair value, gain (loss)	$ 0	$ 388

Equity Investments, at Fair Value - Schedule of Income From Multi-Family Preferred Equity Ownership Interests (Details) - Multi-Family Preferred Equity Ownership Interests - Equity investments - USD ($)
$ in Thousands