Investments in Apartment/Mixed-use as of September 30, 2023 (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	$ 498,119	$ 493,324
Cash and cash equivalents	8,814	7,937
Unrealized rents & receivables	6,990	5,577
Deferred costs	5,838	3,802
Total Assets	701,157	701,084
Secured notes payable	273,938	276,801
Other liabilities	6,635	11,023
Capital – Third Parties	410,790	407,145
Total Liabilities and Capital	701,157	701,084
Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	519,761	510,640
Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	148,740	135,333
Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	90,448	87,483
Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	519,761	510,640
Buzzard Point Sponsor Partnership [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	0	0
Cash and cash equivalents	0	0
Unrealized rents & receivables	0	0
Deferred costs	4,584	2,906
Secured notes payable	0	0
Other liabilities	0	0
Buzzard Point Sponsor Partnership [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	4,584	2,906
Buzzard Point Sponsor Partnership [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	2,292	1,453
Buzzard Point Sponsor Partnership [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	2,292	1,453
Buzzard Point Sponsor Partnership [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	4,584	2,906
Bryant Street Partnerships [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	187,693	192,904
Cash and cash equivalents	1,661	1,349
Unrealized rents & receivables	6,141	5,128
Deferred costs	420	393
Secured notes payable	116,922	129,263
Other liabilities	2,786	2,338
Bryant Street Partnerships [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	195,915	199,774
Bryant Street Partnerships [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	59,132	53,553
Bryant Street Partnerships [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	17,075	14,620
Bryant Street Partnerships [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	195,915	199,774
Estero Partnership [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	34,416	33,008
Cash and cash equivalents	4,287	5,497
Unrealized rents & receivables	0	0
Deferred costs	0	0
Secured notes payable	16,000	16,000
Other liabilities	174	5
Estero Partnership [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	38,703	38,505
Estero Partnership [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	3,605	3,600
Estero Partnership [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	18,924	18,900
Estero Partnership [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	38,703	38,505
Verge [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	129,145	130,616
Cash and cash equivalents	1,170	359
Unrealized rents & receivables	309	14
Deferred costs	354	139
Secured notes payable	72,402	66,584
Other liabilities	1,102	5,328
Verge [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	130,978	131,128
Verge [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	35,261	36,348
Verge [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	22,213	22,868
Verge [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	130,978	131,128
Greenville Partnerships [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	96,834	95,883
Cash and cash equivalents	1,595	567
Unrealized rents & receivables	83	13
Deferred costs	105	88
Secured notes payable	67,414	64,954
Other liabilities	2,243	3,014
Greenville Partnerships [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	98,617	96,551
Greenville Partnerships [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	10,858	11,087
Greenville Partnerships [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	18,102	17,496
Greenville Partnerships [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	98,617	96,551
Apartment Mixed Use [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	448,088	452,411
Cash and cash equivalents	8,713	7,772
Unrealized rents & receivables	6,533	5,155
Deferred costs	5,463	3,526
Secured notes payable	272,738	276,801
Other liabilities	6,305	10,685
Apartment Mixed Use [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	468,797	468,864
Apartment Mixed Use [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	111,148	106,041
Apartment Mixed Use [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	78,606	75,337
Apartment Mixed Use [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	$ 468,797	$ 468,864