XML 42 R51.htm IDEA: XBRL DOCUMENT
v3.19.3

Note 8 - Loans and Related Allowance for Loan and Lease Losses - Impaired Loans by Class (Details) - USD ($) $ in Thousands | Sep. 30, 2019 | Dec. 31, 2018
--- | --- | ---
Recorded investment, with no related allowance | $ 4,996 | $ 3,380
Unpaid principal balance, with no related allowance | 6,027 | 4,061
Recorded investment, with related allowance | 9,503 | 10,695
Unpaid principal balance, with related allowance | 9,562 | 11,406
Related allowance | 706 | 1,354
Recorded investment | 14,499 | 14,075
Unpaid principal balance | 15,589 | 15,467
Commercial Loans [Member] |  |
Recorded investment, with related allowance | 8,700 |
Unpaid principal balance, with related allowance | 8,710 |
Related allowance | 670 |
Commercial And Industrial [Member] |  |
Recorded investment, with no related allowance | 1,308 | 207
Unpaid principal balance, with no related allowance | 2,059 | 413
Recorded investment, with related allowance | 149 | 2,363
Unpaid principal balance, with related allowance | 149 | 3,013
Related allowance | 3 | 667
Recorded investment | 1,457 | 2,570
Unpaid principal balance | 2,208 | 3,426
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member] |  |
Recorded investment, with no related allowance | 1,126 | 1,306
Unpaid principal balance, with no related allowance | 1,406 | 1,462
Recorded investment, with related allowance |  | 664
Unpaid principal balance, with related allowance |  | 715
Related allowance | 33 | 43
Recorded investment | 1,780 | 1,970
Unpaid principal balance | 2,109 | 2,177
Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member] |  |
Recorded investment, with no related allowance | 2,561 | 1,867
Unpaid principal balance, with no related allowance | 2,561 | 2,186
Recorded investment, with related allowance |  | 7,666
Unpaid principal balance, with related allowance |  | 7,676
Related allowance | 670 | 643
Recorded investment | 11,261 | 9,533
Unpaid principal balance | 11,271 | 9,862
Consumer Portfolio Segment [Member] |  |
Recorded investment, with no related allowance |  | 2
Unpaid principal balance, with no related allowance |  | 2
Recorded investment, with related allowance | 1 |
Unpaid principal balance, with related allowance | 1 |
Related allowance |  | 1
Recorded investment | 1 | 2
Unpaid principal balance | 1 | $ 2
Real Estate Construction Porfolio Segment [Member] | Residential Loan [Member] |  |
Recorded investment, with related allowance | 654 |
Unpaid principal balance, with related allowance | 703 |
Related allowance | $ 33 |

X
- Definition Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953550-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of allowance for credit losses related to recorded investment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableRelatedAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in impaired financing receivables for which there is no related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953550-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in impaired financing receivables for which there is a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953550-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbcn_CommercialLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=mbcn_CommercialAndIndustrialMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=mbcn_RealEstateMortgagePortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbcn_ResidentialLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=mbcn_RealEstateConstructionPorfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |