Investments in Apartment/Mixed Use Joint Ventures as of December 31, 2021 (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	$ 472,317	$ 451,767
Cash and cash equivalents	2,987	21,649
Unrealized rents & receivables	4,342	1,102
Deferred costs	898	4,038
Total Assets	678,190	536,360	$ 538,148
Secured notes payable	222,635	180,890
Other liabilities	28,253	34,126
Capital – Third Parties	396,423	367,654
Total Liabilities and Capital	678,190	536,360
Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	480,544	478,556
Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	139,981	174,792
Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	89,675	88,748
Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	480,544	478,556
Riverfront Holdings I I L L C [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	0	105,737
Cash and cash equivalents	0	2,626
Unrealized rents & receivables	0	13
Deferred costs	0	162
Secured notes payable	0	64,982
Other liabilities	0	4,189
Riverfront Holdings I I L L C [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	0	108,538
Riverfront Holdings I I L L C [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	0	34,667
Riverfront Holdings I I L L C [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	0	4,700
Riverfront Holdings I I L L C [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	0	108,538
Bryant Street Partnerships [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	199,730	173,560
Cash and cash equivalents	1,123	111
Unrealized rents & receivables	2,925	58
Deferred costs	304	85
Secured notes payable	119,201	72,471
Other liabilities	9,066	22,952
Bryant Street Partnerships [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	204,082	173,814
Bryant Street Partnerships [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	57,555	58,559
Bryant Street Partnerships [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	18,260	19,832
Bryant Street Partnerships [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	204,082	173,814
D S T Hickory Creek [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	43,840	45,379
Cash and cash equivalents	827	1,202
Unrealized rents & receivables	1,044	775
Deferred costs	337	405
Secured notes payable	29,337	29,291
Other liabilities	115	107
D S T Hickory Creek [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	46,048	47,761
D S T Hickory Creek [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	4,423	4,894
D S T Hickory Creek [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	12,173	13,469
D S T Hickory Creek [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	46,048	47,761
Half St Owner L L C [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	93,504	37,452
Cash and cash equivalents	428	14,011
Unrealized rents & receivables	0	2
Deferred costs	0	2,810
Secured notes payable	18,404	0
Other liabilities	14,470	1,953
Half St Owner L L C [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	93,932	54,275
Half St Owner L L C [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	37,478	37,466
Half St Owner L L C [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	23,580	14,856
Half St Owner L L C [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	93,932	54,275
Greenville Woodfield Partnerships [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	87,421	42,668
Cash and cash equivalents	279	3,554
Unrealized rents & receivables	5	0
Deferred costs	26	235
Secured notes payable	44,309	1,776
Other liabilities	4,462	4,774
Greenville Woodfield Partnerships [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	87,731	46,457
Greenville Woodfield Partnerships [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	15,584	15,963
Greenville Woodfield Partnerships [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	23,376	23,944
Greenville Woodfield Partnerships [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	87,731	46,457
Apartment Mixed Use [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	424,495	404,796
Cash and cash equivalents	2,657	21,504
Unrealized rents & receivables	3,974	848
Deferred costs	667	3,697
Secured notes payable	211,251	168,520
Other liabilities	28,113	33,975
Apartment Mixed Use [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	431,793	430,845
Apartment Mixed Use [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	115,040	151,549
Apartment Mixed Use [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	77,389	76,801
Apartment Mixed Use [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	$ 431,793	$ 430,845