Commitments and contingencies (Narrative) (Details)	12 Months Ended
Oct. 31, 2018 USD ($)
Commercial space leases, net book value	$ 152,600,000
Lease terms for tenants, periods	2 years
Westwood Plaza Shopping Center [Member]
Flood insurance, amount per incident	$ 500,000

The amount of property, by major property class, net of accumulated depreciation, subject to or available for lease as of the balance sheet date.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84164653&loc=d3e41551-112718

Name:	us-gaap_PropertySubjectToOrAvailableForOperatingLeaseNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant