XML 34 R21.htm IDEA: XBRL DOCUMENT
v3.20.2

Note 15 - Custodial Risk | 9 Months Ended
--- | ---
Sep. 30, 2020
Notes to Financial Statements |
Custodial Risk Disclosure [Text Block] | NOTE 15. CUSTODIAL RISK As of September 30, 2020, we had approximately $46,130,380 in excess of federally insured limits on deposit with financial institutions comprised of cash funds, funds held as collateral assets, and short-term CDs.

X
- Definition A complete disclosure of custodial risk. + References No definition available. + Details
Name: | bomn_CustodialRiskDisclosureTextBlock
Namespace Prefix: | bomn_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_DisclosureTextBlockAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration