Mortgages, construction loan payable and credit line (Schedule of Debt) (Details) - USD ($)	Oct. 31, 2017	Nov. 23, 2016	Oct. 31, 2016
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ 1,863,000		$ 2,521,000
Total mortgages, notes payable and credit line	323,435,000		329,719,000
Mortgages [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	181,757,000		215,752,000
Unamortized debt issuance costs	1,530,000		1,887,000
Mortgages [Member] | Frederick, MD [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans			22,000,000
Unamortized debt issuance costs			23,000
Mortgages [Member] | Rockaway, NJ Mortgage [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	16,660,000		17,141,000
Unamortized debt issuance costs	109,000		138,000
Mortgages [Member] | Westwood, NJ #2 [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	20,220,000		20,801,000
Unamortized debt issuance costs	166,000		197,000
Mortgages [Member] | Patchogue, NY [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	5,231,000		5,231,000
Unamortized debt issuance costs	2,000		25,000
Mortgages [Member] | Wayne, NJ Mortgage 1 [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	17,705,000		18,054,000
Unamortized debt issuance costs	44,000		70,000
Mortgages [Member] | River Edge, NJ First Mortgage [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	10,456,000		10,659,000
Unamortized debt issuance costs	104,000		122,000
Mortgages [Member] | Refinanced Maywood, NJ Mortgage [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans			8,087,000
Unamortized debt issuance costs			99,000
Mortgages [Member] | Westwood, NJ #3 [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	20,628,000		21,098,000
Unamortized debt issuance costs	101,000		135,000
Mortgages [Member] | Second Wayne, NJ Mortgage [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	25,102,000		25,749,000
Unamortized debt issuance costs	308,000		332,000
Mortgages [Member] | Hackensack, NJ [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	29,198,000		29,901,000
Unamortized debt issuance costs	98,000		50,000
Mortgages [Member] | Damascus, MD [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	20,357,000		20,831,000
Unamortized debt issuance costs	362,000		427,000
Total mortgages, notes payable and credit line	20,000,000		20,000,000
Mortgages [Member] | Middletown, NY Mortgage [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	16,200,000		16,200,000
Unamortized debt issuance costs	236,000		269,000
Notes Payable, Other Payables [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	333,000		634,000
Total mortgages, notes payable and credit line	141,678,000		113,967,000
Notes Payable, Other Payables [Member] | Frederick, MD [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	209,000
Total mortgages, notes payable and credit line	23,241,000
Notes Payable, Other Payables [Member] | Baltimore, MD [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs			634,000
Total mortgages, notes payable and credit line	115,300,000	$ 2,100,000	113,967,000
Provident Bank [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ 124,000
Total mortgages, notes payable and credit line