Represents transfers of assets or liabilities between the levels of the fair value hierarchy during the period.

No definition available.

Name:	bhoi_FairValueAssetsAndLiabilitiesAmountOfTransfersBetweenLevelsOfFairValue
Namespace Prefix:	bhoi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Fair Value Inputs, Expense Growth Rate

+ References

No definition available.

+ Details

Name:	bhoi_FairValueInputsExpenseGrowthRate
Namespace Prefix:	bhoi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value on a nonrecurring basis by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

+ References

No definition available.

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_FairValueInputsAssetsQuantitativeInformationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Ratio of the net operating income produced by an asset and its capital cost (original prices paid to buy the asset), used as an input to measure fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueInputsCapRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

+ References

+ Details

Name:	us-gaap_FairValueInputsDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of assumed long-term growth in revenues, used as an input to measure fair value.

+ References

+ Details

Name:	us-gaap_FairValueInputsLongTermRevenueGrowthRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Cost of construction of real property stated is a price per square foot, used as an input to measure fair value.

+ References

+ Details

Name:	us-gaap_FairValueInputsPricePerSquareFoot
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

The charge against earnings in the period to reduce the carrying amount of real property to fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=51719941&loc=d3e2921-110230

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

+ Details

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

- Details

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

- Details

Name:	us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=bhoi_NorthboroughTowerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=bhoi_CondominiumsFinishedUnitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
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- Details

Name:	us-gaap_ValuationTechniqueAxis=us-gaap_MarketApproachValuationTechniqueMember
Namespace Prefix:
Data Type:	na
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Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
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- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsNonrecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationTechniqueAxis=bhoi_DiscountedCashFlowMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=bhoi_InvestmentBuildingandBuildingImprovementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationTechniqueAxis=us-gaap_IncomeApproachValuationTechniqueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_LandAndLandImprovementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=bhoi_InventoryRealEstateMember
Namespace Prefix:
Data Type:	na
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Period Type:

Assets and Liabilities Measured at Fair Value (Level 3 Fair Value Measurements) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quantitative Information about Level 3 Fair Value Measurements
Impairment charge		$ 11,540,000	$ 9,371,000	$ 363,000
Amount of transfers between levels of fair value		$ 0	0
Buildings and improvements, net \| Northborough office building
Quantitative Information about Level 3 Fair Value Measurements
Impairment charge	$ 9,400,000
Condominium inventory (finished units) \| Minimum [Member] \| Market comparable
Quantitative Information about Level 3 Fair Value Measurements
Amount per condo unit due to limited market comparables (in dollars per square foot)		511
Condominium inventory (finished units) \| Maximum \| Market comparable
Quantitative Information about Level 3 Fair Value Measurements
Amount per condo unit due to limited market comparables (in dollars per square foot)		555
Fair Value, Measurements, Nonrecurring [Member]
Quantitative Information about Level 3 Fair Value Measurements
Impairment charge		$ 12,300,000
Fair Value, Measurements, Nonrecurring [Member] \| Buildings and improvements, net
Quantitative Information about Level 3 Fair Value Measurements
Assets, Fair Value Disclosure, Nonrecurring	19,397,000		19,397,000
Fair Value, Measurements, Nonrecurring [Member] \| Buildings and improvements, net \| Minimum [Member] \| Discounted cash flow
Quantitative Information about Level 3 Fair Value Measurements
Discount rate (percent)		7.75%
Terminal capitalization rate (percent)		8.00%
Market rent growth rate (percent)		0.00%
Expense growth rate (percent)		0.00%
Fair Value, Measurements, Nonrecurring [Member] \| Buildings and improvements, net \| Maximum \| Discounted cash flow
Quantitative Information about Level 3 Fair Value Measurements
Discount rate (percent)		11.50%
Terminal capitalization rate (percent)		9.75%
Market rent growth rate (percent)		3.00%
Expense growth rate (percent)		3.00%
Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Nonrecurring [Member]
Quantitative Information about Level 3 Fair Value Measurements
Assets, Fair Value Disclosure, Nonrecurring		$ 2,201,000
Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Nonrecurring [Member] \| Buildings and improvements, net
Quantitative Information about Level 3 Fair Value Measurements
Assets, Fair Value Disclosure, Nonrecurring	19,397,000	29,500,000	19,397,000
Investment Building and Building Improvements [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Nonrecurring [Member] \| Income Approach Valuation Technique [Member]
Quantitative Information about Level 3 Fair Value Measurements
Assets, Fair Value Disclosure, Nonrecurring	$ 19,397,000	29,500,000	$ 19,397,000
Land and Land Improvements [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Nonrecurring [Member]
Quantitative Information about Level 3 Fair Value Measurements
Assets, Fair Value Disclosure, Nonrecurring		19,606,000
Land and Land Improvements [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Nonrecurring [Member] \| Income Approach Valuation Technique [Member]
Quantitative Information about Level 3 Fair Value Measurements
Assets, Fair Value Disclosure, Nonrecurring		19,606,000
Inventory, Real Estate [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Nonrecurring [Member] \| Market comparable
Quantitative Information about Level 3 Fair Value Measurements
Assets, Fair Value Disclosure, Nonrecurring		$ 2,201,000