Investments in Joint Ventures as of June 30, 2022 (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	$ 492,952	$ 472,317
Cash and cash equivalents	4,924	2,987
Unrealized rents & receivables	6,485	4,342
Deferred costs	936	898
Total Assets	677,040	678,190
Secured notes payable	267,426	222,635
Other liabilities	18,705	28,253
Capital - Third Parties	397,802	396,423
Total Liabilities and Capital	677,040	678,190
Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	505,297	480,544
Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	131,892	139,981
Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital - Third Parties	87,274	89,675
Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	505,297	480,544
Brooksville Quarry L L C [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	14,279	14,281
Cash and cash equivalents	178	18
Unrealized rents & receivables	0	0
Deferred costs	4	2
Secured notes payable	0	0
Other liabilities	42	0
Brooksville Quarry L L C [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	14,461	14,301
Brooksville Quarry L L C [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	7,546	7,488
Brooksville Quarry L L C [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital - Third Parties	6,873	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	14,461	14,301
B C F R P Realty L L C [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	21,305	21,561
Cash and cash equivalents	224	312
Unrealized rents & receivables	431	368
Deferred costs	155	229
Secured notes payable	11,093	11,384
Other liabilities	164	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	22,115	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	5,429	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	5,429	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	22,115	22,470
Aberdeen Station [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	917	514
Cash and cash equivalents	0	0
Unrealized rents & receivables	0	0
Deferred costs	0	0
Secured notes payable	0	0
Other liabilities	0	0
Aberdeen Station [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	917	514
Aberdeen Station [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	917	514
Aberdeen Station [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital - Third Parties	0	0
Aberdeen Station [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	917	514
Amber Ridge Loan [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	6,234	11,466
Cash and cash equivalents	0	0
Unrealized rents & receivables	0	0
Deferred costs	0	0
Secured notes payable	0	0
Other liabilities	0	0
Amber Ridge Loan [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	6,234	11,466
Amber Ridge Loan [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	6,234	11,466
Amber Ridge Loan [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital - Third Parties	0	0
Amber Ridge Loan [Member] | Real Estate Partnership Total Liabilities And Capital [Member]
Schedule of Equity Method Investments [Line Items]
Total Liabilities and Capital	6,234	11,466
Apartment Mixed Use [Member]
Schedule of Equity Method Investments [Line Items]
Investments in real estate, net	450,217	424,495
Cash and cash equivalents	4,522	2,657
Unrealized rents & receivables	6,054	3,974
Deferred costs	777	667
Secured notes payable	256,333	211,251
Other liabilities	18,499	28,113
Apartment Mixed Use [Member] | Real Estate Total Assets [Member]
Schedule of Equity Method Investments [Line Items]
Total Assets	461,570	431,793
Apartment Mixed Use [Member] | Real Estate Partnership F R P [Member]
Schedule of Equity Method Investments [Line Items]
Capital - FRP	111,766	115,040
Apartment Mixed Use [Member] | Real Estate Partnership Third Parties [Member]
Schedule of Equity Method Investments [Line Items]
Capital - Third Parties	74,972	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	$ 461,570	$ 431,793