Investments in Apartment/Mixed Use Joint Ventures as of December 31, 2021 (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	$ 483,279	$ 472,317
Cash and cash equivalents	2,914	2,987
Unrealized rents & receivables	6,496	4,342
Deferred costs	946	898
Total Assets	674,867	678,190
Secured notes payable	250,404	222,635
Other liabilities	17,899	28,253
Capital – Third Parties	396,442	396,423
Total Liabilities and Capital	674,867	678,190
Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	493,635	480,544
Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	136,577	139,981
Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	88,755	89,675
Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	493,635	480,544
Riverfront Holdings I I L L C [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	0	0
Total Assets			$ 150,082
Secured notes payable	0	0
Other liabilities	0	0
Capital - FRP			18,513
Capital – Third Parties			44,200
Total Liabilities and Capital			$ 150,082
Riverfront Holdings I I L L C [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	0	0
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	0
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	0
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	0
Bryant Street Partnerships [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	197,423	199,730
Cash and cash equivalents	1,268	1,123
Unrealized rents & receivables	4,923	2,925
Deferred costs	256	304
Secured notes payable	123,850	119,201
Other liabilities	5,241	9,066
Bryant Street Partnerships [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	203,870	204,082
Bryant Street Partnerships [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	56,874	57,555
Bryant Street Partnerships [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	17,905	18,260
Bryant Street Partnerships [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	203,870	204,082
D S T Hickory Creek [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	43,567	43,840
Cash and cash equivalents	673	827
Unrealized rents & receivables	1,119	1,044
Deferred costs	320	337
Secured notes payable	29,348	29,337
Other liabilities	180	115
D S T Hickory Creek [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	45,679	46,048
D S T Hickory Creek [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	4,304	4,423
D S T Hickory Creek [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	11,847	12,173
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	45,679	46,048
Half St Owner L L C [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	106,789	93,504
Cash and cash equivalents	430	428
Unrealized rents & receivables	0	0
Deferred costs	0	0
Secured notes payable	37,058	18,404
Other liabilities	9,102	14,470
Half St Owner L L C [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	107,219	93,932
Half St Owner L L C [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	37,479	37,478
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	23,580
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	107,219	93,932
Greenville Woodfield Partnerships [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	90,234	87,421
Cash and cash equivalents	346	279
Unrealized rents & receivables	7	5
Deferred costs	172	26
Secured notes payable	48,957	44,309
Other liabilities	3,172	4,462
Greenville Woodfield Partnerships [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	90,759	87,731
Greenville Woodfield Partnerships [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	15,452	15,584
Greenville Woodfield Partnerships [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	23,178	23,376
Greenville Woodfield Partnerships [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	90,759	87,731
Apartment Mixed Use [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	438,013	424,495
Cash and cash equivalents	2,717	2,657
Unrealized rents & receivables	6,049	3,974
Deferred costs	748	667
Secured notes payable	239,213	211,251
Other liabilities	17,695	28,113
Apartment Mixed Use [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	447,527	431,793
Apartment Mixed Use [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	114,109	115,040
Apartment Mixed Use [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital – Third Parties	76,510	77,389
Apartment Mixed Use [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	$ 447,527	$ 431,793