REGULATORY ACTION (Details)	Apr. 22, 2010	Sep. 30, 2012 MainSource Bank	Dec. 31, 2011 MainSource Bank
Ratio to comply with regulatory agreement
Tier 1 leverage ratio (as a percent)	8.00%	5.00%
To Comply with Regulatory Agreement (as a percent)			8.00%
To Comply with Regulatory Agreement Ratio (as a percent)			11.00%
Total risk based capital ratio (as a percent)	11.00%	10.00%

The ratio of capital to risk-weighted assets required to be comply with regulatory agreement.

No definition available.

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- Definition

The ratio of Tier 1 capital to risk-wighted assets of Tier 1 required to be comply with regulatory agreement.

+ References

No definition available.

+ Details

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- Definition

The Total risk based capital ratio (total capital divided by risk weighted assets) required to be categorized as "well capitalized", in the regulatory framework for prompt corrective action.

+ References

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

-Publisher AICPA

-Name Audit and Accounting Guide (AAG)

-Number AAG-DEP

-Paragraph 15

-Subparagraph 3a

-IssueDate 2006-05-01

-Chapter 17

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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

-Publisher AICPA

-Name Audit and Accounting Guide (AAG)

-Number AAG-DEP

-Paragraph 22

-IssueDate 2006-05-01

-Chapter 17

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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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- Definition

The amount of Tier 1 Leverage Capital required to be categorized as well capitalized divided by average assets as defined in the regulatory framework for prompt corrective action.

+ References

+ Details

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