ORGANIZATION, BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, Business (Details) ft² in Millions	Apr. 30, 2018 ft² Property
ORGANIZATION, BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Number of properties the Company owned or had equity interest in \| Property	83
Gross leasable area of properties the Company owned or had equity interest in \| ft²	5.1

The Gross Leasable Area of the properties the Company owned or had equity interest in.

No definition available.

Name:	uba_GrossLeasableAreaOfPropertiesTheCompanyOwnedOrHadEquityInterestIn
Namespace Prefix:	uba_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant