Investment in tenancy-in-common (Schedule of balance sheet of Pierre Property) (Details) - USD ($) $ in Thousands	Jul. 31, 2021	Apr. 30, 2021	Jan. 31, 2021	Oct. 31, 2020	Jul. 31, 2020	Apr. 30, 2020	Jan. 31, 2020	Oct. 31, 2019
Schedule of Equity Method Investments [Line Items]
Real estate, net	$ 272,362			$ 278,150
Cash and cash equivalents	36,359			36,860	$ 31,034
Tenants' security accounts	1,343			1,408
Receivables and other assets	1,366			1,811
Total Assets	348,146			355,215
Mortgages payable, net of unamortized debt issuance costs	301,162			305,430
Accounts payable and accrued expenses	2,813			2,277
Tenants' security deposits	2,030			2,124
Deferred revenue	895			1,043
Equity	31,716	$ 32,299	$ 31,920	30,863	$ 40,701	$ 41,205	$ 13,277	$ 16,048
Total Liabilities and Equity	348,146			355,215
FREIT's investment in TIC (65% interest)	19,433			20,101
Pierre Property [Member]
Schedule of Equity Method Investments [Line Items]
Real estate, net	78,533			80,041
Cash and cash equivalents	911			754
Tenants' security accounts	494			523
Receivables and other assets	545			468
Total Assets	80,483			81,786
Mortgages payable, net of unamortized debt issuance costs	49,757			49,956
Accounts payable and accrued expenses	241			314
Tenants' security deposits	495			535
Deferred revenue	93			56
Equity	29,897			30,925
Total Liabilities and Equity	80,483			81,786
FREIT's investment in TIC (65% interest)	$ 19,433			$ 20,101