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Nature of Business - Additional Information (Detail) | 12 Months Ended
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Dec. 31, 2018 Segment Radio-Stations
Organization, Consolidation and Presentation of Financial Statements [Abstract] |
Number of reportable segments | Segment | 1
Radio station owns and operated by entity | Radio-Stations | 64

X
- Definition Number of radio stations owned and operated by entity. + References No definition available. + Details
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Namespace Prefix: | bbgi_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements. + References No definition available. + Details
Name: | us-gaap_NumberOfReportableSegments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

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