XML 75 R65.htm IDEA: XBRL DOCUMENT
v3.21.2

401(k) Retirement Plan (Details) - USD ($) | 3 Months Ended
--- | ---
Sep. 30, 2021 | Sep. 30, 2020
Defined Contribution Plan Disclosure [Line Items] |  |
Retirement plan expenses | $ 490,000 | $ 457,000
Vesting period | 5 years |
Maximum |  |
Defined Contribution Plan Disclosure [Line Items] |  |
Matching contributions of eligible compensation | 4.00% |

X
- Definition Vesting term of retirement plans. + References No definition available. + Details
Name: | smbc_RetirementPlanVestingPeriod
Namespace Prefix: | smbc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of administrative expense incurred by defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanAdministrativeExpenses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage employer matches of the employee's percentage contribution matched. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |