Note 9 - Fair Values (Details Textual) $ in Thousands	9 Months Ended
Sep. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)
Other Real Estate, Ending Balance	$ 58	$ 31
Collateral Impaired Loans [Member]
Collateral Dependent Impaired Loans Carrying Amount		10,500
Collateral Dependent Impaired Loans, Fair Value Disclosure	10,200
Allowance for Loan and Lease Losses, Adjustments, Other	328
Other Real Estate Owned [Member]
Allowance for Loan and Lease Losses, Adjustments, Other	$ 43
Number of Real Estate Properties	2
OREO Carrying Amount		$ 101
Other Real Estate, Ending Balance	$ 58
Measurement Input, Cost to Sell [Member] \| Minimum [Member]
Other Real Estate Owned, Measurement Input	0.41
Measurement Input, Cost to Sell [Member] \| Maximum [Member]
Other Real Estate Owned, Measurement Input	0.43

The carrying amount on collateral dependent impaired loans.

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Namespace Prefix:	boch_
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Balance Type:	debit
Period Type:	instant

- Definition

Represents the fair value portion of collateral dependent impaired loans.

+ References

No definition available.

+ Details

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- Definition

The carrying amount on OREO.

+ References

No definition available.

+ Details

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Namespace Prefix:	boch_
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Period Type:	instant

- Definition

Amount of other addition (reduction) in allowance reserve for credit loss.

+ 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
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

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- Definition

Carrying amount of other real estate not separately disclosed, including, but not limited to, real estate investments, real estate loans that qualify as investments in real estate, and premises that are no longer used in operations may also be included in real estate owned. This does not include real estate assets taken in settlement of troubled loans through surrender or foreclosure.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.10(4))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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Period Type:	instant

- Definition

Value of input used to measure real estate owned by financial institution by financial institution which is not directly related to its business.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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