Fair Value Measurements (Details Textual) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011
Fair Value Measurements (Textual) [Abstract]
Collateral values discounting rate for estimated selling costs	10.00%
Fair Value Measurements (Additional Textual) [Abstract]
Impaired loans, allowance for loan losses	$ 758,000	$ 984,000
Fair value of financial and non financial liabilities	0	0
Other real estate owned carrying value	1,633,000	1,530,000
Other real estate owned gross carrying value	1,825,000	1,599,000
Valuation allowance	192,000	69,000
Transfers of financial instruments from Level 1 to Level 2	0	0
Transfers of financial instruments from Level 2 to Level 1	$ 0	$ 0
Maximum [Member]
Fair Value Measurements (Textual) [Abstract]
Appraisal Collateral Values, Discounting Rate Range	55.00%
Future estimated cash flows discounting rate range	11.00%
Minimum [Member]
Fair Value Measurements (Textual) [Abstract]
Appraisal Collateral Values, Discounting Rate Range	10.00%
Future estimated cash flows discounting rate range	5.00%

Appraisal collateral values discounting rate range.

No definition available.

Name:	somc_AppraisalCollateralValuesDiscountingRateRange
Namespace Prefix:	somc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Collateral values discounting rate for estimated selling costs.

+ References

No definition available.

+ Details

Name:	somc_CollateralValuesDiscountingRateForEstimatedSellingCosts
Namespace Prefix:	somc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Estimated cash flows present value discounting rate range.

+ References

No definition available.

+ Details

Name:	somc_EstimatedCashFlowsPresentValueDiscountingRateRange
Namespace Prefix:	somc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	somc_FairValueMeasurementsAdditionalTextualAbstract
Namespace Prefix:	somc_
Data Type:	xbrli:stringItemType
Balance Type:	na
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- Details

Name:	somc_FairValueMeasurementsTextualAbstract
Namespace Prefix:	somc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Other real estate owned fair value disclosure.

+ References

No definition available.

+ Details

Name:	somc_OtherRealEstateOwnedFairValueDisclosure
Namespace Prefix:	somc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Other real estate owned valuation allowance.

+ References

No definition available.

+ Details

Name:	somc_OtherRealEstateOwnedValuationAllowance
Namespace Prefix:	somc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (bb)

-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of transfers of assets measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1.

+ References

+ Details

Name:	us-gaap_FairValueAssetsLevel2ToLevel1TransfersAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of allowance for credit losses related to recorded investment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=7512638&loc=d3e5212-111524

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This element represents the aggregate of the liabilities reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

+ Details

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Period Type:	instant

- Definition

Carrying amount of other real estate not separately disclosed, including, but not limited to, real estate investments, real estate loans that qualify as investments in real estate, and premises that are no longer used in operations may also be included in real estate owned. This does not include real estate assets taken in settlement of troubled loans through surrender or foreclosure.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.10(4))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Audit and Accounting Guide (AAG)

-Number AAG-DEP

-Paragraph 12-18

-IssueDate 2006-05-01

-Chapter 11

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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Balance Type:	debit
Period Type:	instant