Note 10 - Federal Funds Purchased and Lines of Credit (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Note 10 - Federal Funds Purchased and Lines of Credit (Details) [Line Items]
Federal Funds Purchased	$ 0us-gaap_FederalFundsPurchased	$ 0us-gaap_FederalFundsPurchased
Line of Credit Facility, Number of Lenders	3
Collateralized Agreements	40,000,000us-gaap_CollateralizedAgreements
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Interest Rate, Range from	0.30%
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Interest Rate, Range to	1.15%
Federal Home Loan Bank (FHLB) [Member]
Note 10 - Federal Funds Purchased and Lines of Credit (Details) [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	192,100,000
Federal Reserve [Member]
Note 10 - Federal Funds Purchased and Lines of Credit (Details) [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 30,000,000

The number of lenders granting funds under lines of credit.

No definition available.

Name:	boch_LineOfCreditFacilityNumberOfLenders
Namespace Prefix:	boch_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Details

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Namespace Prefix:	boch_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The total of collateralized agreements including securities purchased under agreements to resell (repos), borrowed securities, and secured demand notes.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(m)(2)(i)(A))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 10

-Section 05

-Paragraph 16

-URI http://asc.fasb.org/extlink&oid=7517284&loc=d3e93640-111703

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of short term borrowing where a bank borrows, at the federal funds rate, from another bank.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.13(1))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 13

-Subparagraph 1

-Article 9

+ Details

Name:	us-gaap_FederalFundsPurchased
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Discloses the lowest interest rate applicable to any of the advances from the Federal Home Loan Bank, by branch, as of the Balance Sheet date.

+ References

+ Details

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

- Definition

Discloses the highest interest rate applicable to any of the advances from the Federal Home Loan Bank, by branch, as of the Balance Sheet date.

+ References

+ Details

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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=boch_FederalReserveMember
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