BALANCE SHEETS (Parenthetical)	Jan. 31, 2013	Jan. 31, 2012
BALANCE SHEETS
Certificate of beneficial interest of Land Trust, units	13,120,010	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