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Regulatory Capital - Capital Ratios (Detail) | Dec. 31, 2015 | Dec. 31, 2014
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Adequately capitalized ratio | 4.00% | 4.00%
Adequately capitalized ratio plus capital conservation buffer | 4.00% |
Tier 1 risk based capital, adequately capitalized, ratio | 6.00% | 4.00%
Adequately capitalized ratio plus capital conservation buffer | 8.50% |
Common equity tier 1 capital, adequately capitalized, ratio | 4.50% |
Adequately capitalized ratio plus capital conservation buffer | 7.00% |
Total risk based capital, adequately capitalized, ratio | 8.00% | 8.00%
Adequately capitalized ratio plus capital conservation buffer | 10.50% |
Middlefield Banking Company [Member] |  |
Leverage capital, actual, ratio | 9.23% | 9.25%
Well-capitalized ratio (Bank only) | 5.00% | 5.00%
Tier 1 risk based capital, actual, ratio | 12.52% | 12.95%
Tier 1 risk based capital, well-capitalized, ratio (bank only) | 8.00% | 6.00%
Tier 1 risk based capital, actual, ratio | 12.52% |
Common equity tier 1 capital, well-capitalized, ratio (bank only) | 6.50% |
The Middlefield Banking Company | 13.73% | 14.19%
Total risk based capital, well-capitalized, ratio (bank only) | 10.00% | 10.00%
Middlefield Banc Corp [Member] |  |
Leverage capital, actual, ratio | 8.69% | 9.60%
Tier 1 risk based capital, actual, ratio | 12.00% | 13.38%
Tier 1 risk based capital, actual, ratio | 12.00% |
The Middlefield Banking Company | 13.20% | 14.64%

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- Definition The minimum common equity tier 1 risk based capital ratio (common equity tier 1 capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References No definition available. + Details
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- Definition The common equity tier 1 risk based capital ratio (common equity tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized", in the regulatory framework for prompt corrective action. + References No definition available. + Details
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- Definition The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958570-112826 + Details
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