Investments in Joint Ventures at December 31, 2021 (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	$ 533,996	$ 472,317
Cash and cash equivalents	9,441	2,987
Unrealized rents & receivables	6,964	4,342
Deferred costs	2,022	898
Total Assets	676,990	678,190
Secured notes payable	298,104	222,635
Other liabilities	15,750	28,253
Capital - Third Parties	398,234	396,423
Total Liabilities and Capital	676,990	678,190
Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	552,423	480,544
Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	138,998	139,981
Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital - Third Parties	99,571	89,675
Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	552,423	480,544
Brooksville Quarry L L C [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	14,307	14,281
Cash and cash equivalents	169	18
Unrealized rents & receivables	0	0
Deferred costs	2	2
Secured notes payable	0	0
Other liabilities	85	0
Brooksville Quarry L L C [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	14,478	14,301
Brooksville Quarry L L C [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	7,532	7,488
Brooksville Quarry L L C [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital - Third Parties	6,861	6,813
Brooksville Quarry L L C [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	14,478	14,301
B C F R P Realty L L C [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	21,185	21,561
Cash and cash equivalents	208	312
Unrealized rents & receivables	433	368
Deferred costs	262	229
Secured notes payable	11,184	11,384
Other liabilities	142	140
B C F R P Realty L L C [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	22,088	22,470
B C F R P Realty L L C [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	5,381	5,473
B C F R P Realty L L C [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital - Third Parties	5,381	5,473
B C F R P Realty L L C [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	22,088	22,470
Aberdeen Station [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net		514
Cash and cash equivalents		0
Unrealized rents & receivables		0
Deferred costs		0
Secured notes payable		0
Other liabilities		0
Aberdeen Station [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets		514
Aberdeen Station [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP		514
Aberdeen Station [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital - Third Parties		0
Aberdeen Station [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital		514
Amber Ridge Loan [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net		11,466
Cash and cash equivalents		0
Unrealized rents & receivables		0
Deferred costs		0
Secured notes payable		0
Other liabilities		0
Amber Ridge Loan [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets		11,466
Amber Ridge Loan [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP		11,466
Amber Ridge Loan [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital - Third Parties		0
Amber Ridge Loan [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital		11,466
Apartment Mixed Use [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	460,659	424,495
Cash and cash equivalents	3,190	2,657
Unrealized rents & receivables	6,531	3,974
Deferred costs	1,598	667
Secured notes payable	282,104	211,251
Other liabilities	15,523	28,113
Apartment Mixed Use [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	471,978	431,793
Apartment Mixed Use [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	105,922	115,040
Apartment Mixed Use [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital - Third Parties	68,429	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	$ 471,978	$ 431,793