Note 3: Loans and Allowance For Loan Losses: Commercial Real Estate Lending Policy (Details) $ in Thousands	12 Months Ended
Jun. 30, 2015 USD ($)
Commercial Real Estate
Loans on Properties Outside Primary Lending Area	$ 73,900

Represents the monetary amount of Loans on Properties Outside Primary Lending Area, during the indicated time period.

No definition available.

Name:	smbc_LoansOnPropertiesOutsidePrimaryLendingArea
Namespace Prefix:	smbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration