Investments in Joint Ventures (Details Narrative) $ in Thousands	1 Months Ended	3 Months Ended				12 Months Ended
	May 31, 2016 USD ($)	Mar. 31, 2019 USD ($) integer	Mar. 31, 2018 USD ($)	Mar. 31, 2016 USD ($) a ft²	Dec. 31, 2006 USD ($)	Dec. 31, 2018 USD ($) integer	Dec. 31, 2017	Mar. 13, 2019 USD ($)	Dec. 24, 2018 a	May 04, 2018 USD ($)	Jan. 27, 2018 USD ($)	Sep. 28, 2017 USD ($) integer	Oct. 04, 2006 a
Company's share of the loss of the joint venture		$ 264	$ 12			$ 88
Joint Venture consolidated retained earnings		(2,895)				$ (2,702)
Cash contribution		5,676	$ 28
Difference between capital recorded by the Company and the joint ventures		11,358
BC FRP Realty, LLC Debt
Construction financing through September 15, 2022												$ 17,250
Interest rate over LIBOR							2.50%
Outstanding balance		10,110
Buildings | integer												4
Eagle BankRiverFront Holdings II, LLC
Interest rate over LIBOR						3.25%
Outstanding balance		$ 2,230
Loan commitment										$ 71,000
Loan description						The loan is interest only and matures in 36 months with a 12 month extension assuming completion of construction and at least one occupancy. There is a provision for an additional 72 months extension with a 30 year amortization of principal at 2.15% over 7 year US Treasury Constant if NOI is sufficient for a 9% yield.
Bryant Street Partnerships Construction Loan
Interest rate over LIBOR		2.25%
Outstanding balance		$ 0
Loan commitment								$ 132,000
Loan description		The loan matures March 13, 2023 with up to two extension of one year each upon certain conditions.
Vulcan
Joint venture percentage stake													50.00%
Acres conributed | a													553
Vulcan leasehold interest | a													3,443
FRP additional contribution for land					$ 3,018
Additional land acquired | a													288
St Johns Properties JV St Johns
Value of land contributed				$ 3,240
Joint venture percentage stake				50.00%
Acres conributed | a				10
MRP
Other ownership capital contribution						$ 5,600
Development fee						$ 725
Brooksville Quarry, LLC
Land acreage | a													4,300
Joint venture percentage stake		50.00%				50.00%							50.00%
Acres conributed | a													3,443
Book value of land contribution					2,548
FRP additional contribution for land					$ 3,018
Additional land acquired | a													288
Company's share of the loss of the joint venture		$ 10				$ 61
BC FRP Realty, LLC
Square feet | ft²				329,000
Value of land contributed				$ 7,500
Joint venture percentage stake		50.00%		50.00%		50.00%
Distribution received	$ 2,130
Acres conributed | a				25
Company's share of the loss of the joint venture		$ 170				$ 0
Essexshire Loan
Company's share of the loss of the joint venture		0				(39)
Equity method loan balance		$ 755
Loan commitment											$ 9,200
Interest rate											10.00%
Preferred return											20.00%
No. of townhomes | integer		122
No. Single family homes | integer		4
RiverFront Holdings II, LLC
Value of land contributed						$ 16,300
Joint venture percentage stake		80.00%				80.00%
Book value of land contribution						$ 4,600
Company's share of the loss of the joint venture		$ 178				66
Cash contribution						6,200
Preferred equity financing						$ 13,750
Preferred equity financing advanced		$ 13,750
Preferred equity financing interest rate						7.50%
Bryant Street Partnerships
Number of partnerships | integer						4
Land acreage | a									5
Joint venture percentage stake		61.36%				61.36%
Company's share of the loss of the joint venture		$ (94)				$ 0
Cash contribution						32,000
Preferred equity financing						$ 23,000
Preferred equity financing interest rate						8.00%