XML 109 R93.htm IDEA: XBRL DOCUMENT
v3.25.2

Employee Benefits - 401(k) Retirement Plan (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Jun. 30, 2025 | Jun. 30, 2024 | Jun. 30, 2023
Employee Benefits |  |  |
Additional profit-sharing contributions of eligible salary | 5.00% |  |
Retirement plan expenses | $ 2.4 | $ 2.8 | $ 2.4
401(k) Retirement Plan Shares Held | 418,000 | 412,000 |
Vesting period | 5 years |  |
Maximum |  |  |
Employee Benefits |  |  |
Matching contributions of eligible compensation | 4.00% |  |

X
- Definition Represents the 401(k) Retirement Plan Shares Held (number of shares), as of the indicated date. + References No definition available. + Details
Name: | smbc_N401KRetirementPlanSharesHeld
Namespace Prefix: | smbc_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

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 Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 70 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480794/715-70-50-1 + Details
Name: | us-gaap_DefinedContributionPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
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: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

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