Condensed Balance Sheets (Parenthetical)	Jul. 31, 2016 shares
Condensed Balance Sheets
Certificate of beneficial interest of land trust, units	13,120,010

Transferable units distributed to shareholders of the predecessor entity as a beneficial interest in the reporting entity.

No definition available.

Name:	msb_CertificateOfBeneficialInterestUnits
Namespace Prefix:	msb_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant