| Fact Group (Combination of Network and Hypercube) | |
| Network: | 104103 - Statement - Classes of Treasury Stock (http://www.abc.com/role/ClassesOfTreasuryStock) |
| Hypercube: | Class of Treasury Stock [Table] (us-gaap:ClassOfTreasuryStockTable) |
| Slicers (applies to each fact value in each table cell) | |
| brm:ReportingEntityMeasure | 0000000001 (http://www.sec.gov/CIK) |
| us-gaap:CreationDateAxis | abc:AsReportedFebruary122011Member |
| dei:LegalEntityAxis | dei:EntityDomain |
| abc:ClassOfTreasuryStockAxis | |||
| brm:ConceptMeasure | Class of Treasury Stock [Domain] | Common Class A [Member] | Common Class B [Member] |
| Class of Treasury Stock [Line Items] | |||
| Class of Treasury Stock [Hierarchy] | |||
| Treasury Stock, Value | 2,000,000 | 1,000,000 | 1,000,000 |
| Treasury Stock, Shares | 10,000 | 10,000 | |
| Treasury Stock, Restrictions | Cursus est ullamcorper vel sollicitudin lacus | Cursus est ullamcorper vel sollicitudin lacus | |