Interest rate cap and swap contracts (Details) - USD ($)			1 Months Ended			3 Months Ended		9 Months Ended
	Feb. 07, 2018	Dec. 07, 2017	Feb. 28, 2020	Sep. 29, 2016	Dec. 29, 2014	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2019	Oct. 31, 2019	Apr. 22, 2016	Dec. 26, 2012
Derivative [Line Items]
Interest rate swap contract liability						$ 5,770,000		$ 5,770,000		$ 2,126,000
Unrealized loss on derivatives							$ 1,000		$ 160,000
Net unrealized gain (loss) on interest rate swap contracts						(272,000)	(2,025,000)	(3,644,000)	(5,210,000)
Damascus Centre Swap [Member]
Derivative [Line Items]
Interest rate swap contract liability						709,000		709,000
Wayne PSC swap [Member]
Derivative [Line Items]
Interest rate swap contract liability						1,571,000		1,571,000
Regency Swap [Member]
Derivative [Line Items]
Interest rate swap contract liability						1,552,000		1,552,000
Station Place [Member]
Derivative [Line Items]
Interest rate swap contract liability						1,938,000		1,938,000
Grande Rotunda LLC [Member]
Derivative [Line Items]
Interest rate swap contract liability						0		0
Station Place [Member]
Derivative [Line Items]
Loan amount		$ 12,350,000				12,200,000		12,200,000
Notional amount of interest rate swap						12,200,000		$ 12,200,000
Fixed interest rate		4.35%
Interest rate swap contract liability										1,034,000
Basis points, interest rate		1.80%
Maturity date of interest rate cap		Dec. 15, 2027						Dec. 31, 2027
Grande Rotunda LLC [Member]
Derivative [Line Items]
Interest rate cap contract liability										0
Unrealized loss on derivatives							$ 1,000		$ 160,000
Wells Fargo Bank [Member]
Derivative [Line Items]
Loan amount	$ 115,300,000
Aareal Capital Corporation [Member]
Derivative [Line Items]
Loan amount	118,500,000
Available to draw	$ 3,380,000
Basis points, interest rate	2.85%
Maturity date of loan	Feb. 06, 2021
Grande Rotunda LLC Loan [Member]
Derivative [Line Items]
Derivative notional amount						121,900,000		$ 121,900,000
Maturity date of interest rate cap								Mar. 05, 2021
Grande Rotunda LLC Loan [Member] | Two Years [Member]
Derivative [Line Items]
Loan amount						118,500,000		$ 118,500,000
Notional amount of interest rate cap						$ 121,900,000		$ 121,900,000
Interest rate cap						3.00%		3.00%
Maturity date of interest rate cap								Mar. 05, 2020
Grande Rotunda LLC Loan [Member] | One Year [Member]
Derivative [Line Items]
Notional amount of interest rate cap			$ 121,900,000
Interest rate cap			3.00%
Maturity date of interest rate cap			Mar. 05, 2020
Wayne PSC, LLC Loan [Member]
Derivative [Line Items]
Refinanced loan amount				$ 24,200,000
Loan amount				$ 25,800,000		$ 23,200,000		$ 23,200,000
Notional amount of interest rate swap						23,300,000		$ 23,300,000
Fixed interest rate				3.625%
Basis points, interest rate				2.20%
Maturity date of interest rate cap				Oct. 01, 2026				Oct. 31, 2026
People's United Bank [Member]
Derivative [Line Items]
Loan amount						19,000,000		$ 19,000,000
Notional amount of interest rate swap						$ 19,000,000		$ 19,000,000
Maturity date of loan								Jan. 31, 2023
People's United Bank [Member] | Tranche One [Member]
Derivative [Line Items]
Loan amount												$ 20,000,000
Fixed interest rate						3.81%		3.81%
Basis points, interest rate								2.10%
Maturity date of loan								Jan. 03, 2023
People's United Bank [Member] | Tranche Two [Member]
Derivative [Line Items]
Loan amount											$ 2,320,000
Fixed interest rate						3.53%		3.53%
Regency Loan [Member]
Derivative [Line Items]
Refinanced loan amount					$ 16,200,000
Loan amount						$ 15,300,000		$ 15,300,000
Notional amount of interest rate swap						$ 15,300,000		$ 15,300,000
Fixed interest rate						3.75%		3.75%
Basis points, interest rate					1.25%
Maturity date of loan					Dec. 15, 2024			Dec. 31, 2024
Damascus Centre [Member]
Derivative [Line Items]
Interest rate swap contract liability										179,000
Wayne PSC swap [Member]
Derivative [Line Items]
Interest rate swap contract liability										53,000
Regency Swap [Member]
Derivative [Line Items]
Interest rate swap contract liability										$ 860,000