Note 6 - Business Acquisitions - Schedule of Allocation of the Purchase Price (Details) - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2017
Amortization of intangible assets acquired for the period	$ 154,797	$ 256,158
Revenues since the acquisition date included in the consolidated statement of operations for the period	309,078	517,172
Earnings since the acquisition date included in the consolidated statement of operations for the period	(37,003)	(40,069)
Costs of acquisition included in professional fees in the consolidated statement of operations for the period	22,394	44,676
Clear Channel Outdoor Inc. [Member]
Amortization of intangible assets acquired for the period	70,846	141,693
Revenues since the acquisition date included in the consolidated statement of operations for the period	204,093	359,076
Earnings since the acquisition date included in the consolidated statement of operations for the period	(21,391)	(41,755)
Costs of acquisition included in professional fees in the consolidated statement of operations for the period		14,468
Hartlind Outdoor LLC [Member]
Amortization of intangible assets acquired for the period	45,770	76,284
Revenues since the acquisition date included in the consolidated statement of operations for the period	99,665	152,776
Earnings since the acquisition date included in the consolidated statement of operations for the period	38,431	55,729
Costs of acquisition included in professional fees in the consolidated statement of operations for the period	831	8,645
Southeastern US [Member]
Amortization of intangible assets acquired for the period	38,181	38,181
Revenues since the acquisition date included in the consolidated statement of operations for the period	5,320	5,320
Earnings since the acquisition date included in the consolidated statement of operations for the period	(54,043)	(54,043)
Costs of acquisition included in professional fees in the consolidated statement of operations for the period	21,563	21,563
Clear Channel Outdoor, Hartlind and Southeastern US [Member]
Amortization of intangible assets acquired for the period	154,797	256,158
Revenues since the acquisition date included in the consolidated statement of operations for the period	309,078	517,172
Earnings since the acquisition date included in the consolidated statement of operations for the period	(37,003)	(40,069)
Costs of acquisition included in professional fees in the consolidated statement of operations for the period	22,394	44,676
Surety Support Services, Inc [Member]
Amortization of intangible assets acquired for the period
Revenues since the acquisition date included in the consolidated statement of operations for the period
Earnings since the acquisition date included in the consolidated statement of operations for the period
Costs of acquisition included in professional fees in the consolidated statement of operations for the period
South Coast Surety Insurance Services, LLC [Member]
Amortization of intangible assets acquired for the period
Revenues since the acquisition date included in the consolidated statement of operations for the period
Earnings since the acquisition date included in the consolidated statement of operations for the period
Costs of acquisition included in professional fees in the consolidated statement of operations for the period
Free State Bonds Inc. [Member]
Amortization of intangible assets acquired for the period
Revenues since the acquisition date included in the consolidated statement of operations for the period
Earnings since the acquisition date included in the consolidated statement of operations for the period
Costs of acquisition included in professional fees in the consolidated statement of operations for the period
Surety Support Services, South Cost Surety Insurances Services LLC, and Free State Bonds Inc. [Member]
Amortization of intangible assets acquired for the period
Revenues since the acquisition date included in the consolidated statement of operations for the period
Earnings since the acquisition date included in the consolidated statement of operations for the period
Costs of acquisition included in professional fees in the consolidated statement of operations for the period

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

+ Details

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

- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 23
-URI http://asc.fasb.org/extlink&oid=84229725&loc=d3e1043-128460

+ Details

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

- Definition

This element represents the amount of earnings or loss of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

+ Details

Name:	us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_BusinessAcquisitionAxis=bomn_ClearChannelOutdoorIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=bomn_HartlindOutdoorLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=bomn_SoutheasternUSMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=bomn_ClearChannelOutdoorHartlindAndSoutheasternUsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=bomn_SuretySupportServicesIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=bomn_SouthCoastSuretyInsuranceServicesLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=bomn_FreeStateBondsIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=bomn_SuretySupportServicesSouthCostSuretyInsurancesServicesLLCAndFreeStateBondsIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: