XML 61 R48.htm IDEA: XBRL DOCUMENT
v3.20.2

Note 8 - Investments, Including Investments Accounted for Using the Equity Method - Trading Securities (Details) - USD ($) | Sep. 30, 2020 | Dec. 31, 2019
--- | --- | ---
Marketable equity securities, Cost | $ 81,823,525 | $ 49,554,926
Marketable equity securities, Gross Unrealized Gain (Loss) | (18,028,972) | 6,353,001
Marketable equity securities | $ 63,794,553 | $ 55,907,927

X
- Definition The accumulated unrealized gain (loss) on equity securities. + References No definition available. + Details
Name: | bomn_EquitySecuritiesFvniAccumulatedUnrealizedGainLoss
Namespace Prefix: | bomn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=99377092&loc=SL75136599-209740 + Details
Name: | us-gaap_EquitySecuritiesFvNi
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Cost of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Excludes equity method investment and investment in equity security without readily determinable fair value. + References No definition available. + Details
Name: | us-gaap_EquitySecuritiesFvNiCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant