XML 30 R89.htm IDEA: XBRL DOCUMENT v2.4.1.9

Note 15 - Regulatory Restrictions (Details) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended	63 Months Ended
	Apr. 30, 2012	Dec. 31, 2014	Dec. 31, 2013	Jan. 14, 2013
Note 15 - Regulatory Restrictions (Details) [Line Items]
Reserves Required by Federal Reserve Bank		$ 6.8mbcn_ReservesRequiredByFederalReserveBank	$ 7.4mbcn_ReservesRequiredByFederalReserveBank
Percent of Common Stock			10.00%mbcn_PercentOfCommonStock
Pursuant to Regulatory Clearance [Member] | One Investor [Member]
Note 15 - Regulatory Restrictions (Details) [Line Items]
Maximum Ownership of Stock				24.99%mbcn_MaximumOwnershipOfStock / us-gaap_CounterpartyNameAxis = mbcn_OneInvestorMember / us-gaap_StatementScenarioAxis = mbcn_PursuantToRegulatoryClearanceMember
One Investor [Member]
Note 15 - Regulatory Restrictions (Details) [Line Items]
Stock Issued During Period, Shares, New Issues	196,635us-gaap_StockIssuedDuringPeriodSharesNewIssues / us-gaap_CounterpartyNameAxis = mbcn_OneInvestorMember
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	9.90%us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners / us-gaap_CounterpartyNameAxis = mbcn_OneInvestorMember
Maximum Ownership of Stock		10.00%mbcn_MaximumOwnershipOfStock / us-gaap_CounterpartyNameAxis = mbcn_OneInvestorMember
Emerald Bank [Member]
Note 15 - Regulatory Restrictions (Details) [Line Items]
Nonperforming Assets Sold		5.8mbcn_NonperformingAssetsSold / dei_LegalEntityAxis = mbcn_EmeraldBankMember
Middlefield Banking Company [Member]
Note 15 - Regulatory Restrictions (Details) [Line Items]
Amount Available for Payment of Dividends			$ 10.2mbcn_AmountAvailableForPaymentOfDividends / dei_LegalEntityAxis = mbcn_MiddlefieldBankingCompanyMember

X

- Definition

Amount available for payment of dividends.

+ References

No definition available.

+ Details

Name:	mbcn_AmountAvailableForPaymentOfDividends
Namespace Prefix:	mbcn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Maximum ownership of stock.

+ References

No definition available.

+ Details

Name:	mbcn_MaximumOwnershipOfStock
Namespace Prefix:	mbcn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Nonperforming assets sold.

+ References

No definition available.

+ Details

Name:	mbcn_NonperformingAssetsSold
Namespace Prefix:	mbcn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

Name:	mbcn_Note15RegulatoryRestrictionsDetailsLineItems
Namespace Prefix:	mbcn_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percent of common stock.

+ References

No definition available.

+ Details

Name:	mbcn_PercentOfCommonStock
Namespace Prefix:	mbcn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Reserves required by Federal Reserve Bank.

+ References

No definition available.

+ Details

Name:	mbcn_ReservesRequiredByFederalReserveBank
Namespace Prefix:	mbcn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Number of new stock issued during the period.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

+ Details

Name:	us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	dei_LegalEntityAxis=mbcn_EmeraldBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	dei_LegalEntityAxis=mbcn_MiddlefieldBankingCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_CounterpartyNameAxis=mbcn_OneInvestorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementScenarioAxis=mbcn_PursuantToRegulatoryClearanceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: