Mortgages payable and credit line (Schedule of Debt) (Details) - USD ($)	Oct. 31, 2018	Oct. 31, 2017	Nov. 23, 2016
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ 3,498,000	$ 1,863,000
Total mortgages, notes payable and credit line	350,504,000	323,435,000
Mortgages [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	209,274,000	181,757,000
Unamortized debt issuance costs	1,884,000	1,530,000
Mortgages [Member] | Rockaway, NJ Mortgage [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	16,152,000	16,660,000
Unamortized debt issuance costs	80,000	109,000
Mortgages [Member] | Westwood, NJ #2 [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	19,611,000	20,220,000
Unamortized debt issuance costs	134,000	166,000
Mortgages [Member] | Patchogue, NY [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	5,231,000	5,231,000
Unamortized debt issuance costs	15,000	2,000
Mortgages [Member] | Wayne, NJ Mortgage 1 [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	17,334,000	17,705,000
Unamortized debt issuance costs	18,000	44,000
Mortgages [Member] | River Edge, NJ First Mortgage [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	10,243,000	10,456,000
Unamortized debt issuance costs	87,000	104,000
Mortgages [Member] | Red Bank, NJ Mortgage [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	12,350,000
Unamortized debt issuance costs	138,000
Mortgages [Member] | Westwood, NJ #3 [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	20,134,000	20,628,000
Unamortized debt issuance costs	67,000	101,000
Mortgages [Member] | Second Wayne, NJ Mortgage [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	24,432,000	25,102,000
Unamortized debt issuance costs	274,000	308,000
Mortgages [Member] | Hackensack, NJ [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	48,000,000	29,198,000
Unamortized debt issuance costs	572,000	98,000
Mortgages [Member] | Damascus, MD [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	19,865,000	20,357,000
Unamortized debt issuance costs	296,000	362,000
Total mortgages, notes payable and credit line	20,000,000
Mortgages [Member] | Middletown, NY Mortgage [Member]
Debt Instrument [Line Items]
Fixed rate mortgage loans	15,922,000	16,200,000
Unamortized debt issuance costs	203,000	236,000
Notes Payable, Other Payables [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	1,614,000	333,000
Total mortgages, notes payable and credit line	141,230,000	141,678,000
Notes Payable, Other Payables [Member] | Frederick, MD [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	70,000	209,000
Total mortgages, notes payable and credit line	22,710,000	23,241,000
Notes Payable, Other Payables [Member] | Baltimore, MD [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	1,439,000
Total mortgages, notes payable and credit line	118,520,000	115,316,000	$ 2,100,000
Provident Bank [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	105,000	124,000
Total mortgages, notes payable and credit line		$ 3,121,000