Name:	mbcn_CapitalRequiredForCapitalAdequacyPlusCapitalConservationBufferToRiskWeightedAssets
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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 plus capital conservation buffer under the regulatory framework for prompt corrective action.

No definition available.

Name:	mbcn_CommonEquityTier1CapitalRequiredForCapitalAdequacyPlusCapitalConservationBuffer
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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.

No definition available.

Name:	mbcn_CommonEquityTier1CapitalRequiredForCapitalAdequacyToRiskWeightedAssets
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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.

No definition available.

Name:	mbcn_CommonEquityTier1CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
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Common equity tier 1 capital divided by risk weighted assets as defined in the regulations.

No definition available.

Name:	mbcn_CommonEquityTier1CapitalToRiskWeightedAssets
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The minimum amount of Tier 1 Leverage Capital for capital adequacy plus conservation buffer purposes divided by average assets as defined in the regulations.

No definition available.

Name:	mbcn_TierOneLeverageCapitalRequiredForCapitalAdequacyPlusConservationBufferToAverageAssets
Namespace Prefix:	mbcn_
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The minimum Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes plus capital conservation buffer under the regulatory framework for prompt corrective action.

No definition available.

Name:	mbcn_TierOneRiskBasedCapitalRequiredForCapitalAdequacyPlusCapitalConservationBufferToRiskWeightedAssets
Namespace Prefix:	mbcn_
Data Type:	dtr-types:percentItemType
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Ratio of minimum total risk-based capital to risk-weighted assets required for capital adequacy as defined by regulatory framework.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1B
-URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826

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Ratio of minimum total risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826

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Ratio of total risk-based capital to risk-weighted assets as defined by regulatory framework.

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Ratio of minimum Tier 1 leverage capital to average assets required for capital adequacy as defined by regulatory framework.

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Ratio of minimum Tier 1 leverage capital to average assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

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Ratio of Tier 1 capital to average assets as defined by regulatory framework.

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Ratio of minimum Tier 1 risk-based capital to risk-weighted assets required for capital adequacy as defined by regulatory framework.

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Ratio of minimum Tier 1 risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

Name:	us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix:	us-gaap_
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Ratio of Tier 1 risk-based capital to risk-weighted assets as defined by regulatory framework.