| r0.1 | label_boi_a2/Avg. weighted amortization rate, pct. | boi_met:md353 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_MU:x1 | boi_RP:x24 |
| r0.2 | label_boi_a2/Cost | boi_met:mi376 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_RP:x24 |
| r0.3 | label_boi_a2/Accrued amortization | boi_met:mi346 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | N/A | boi_RP:x24 |
| r0.4 | label_boi_a2/Provision for decrease in value | boi_met:md348 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | N/A | boi_MU:x1 | boi_RP:x24 |
| r0.5 | label_boi_a2/Avg. weighted amortization rate, pct. | boi_met:md353 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_MU:x1 | boi_RP:x24 |
| r0.6 | label_boi_a2/Cost | boi_met:mi376 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_RP:x24 |
| r0.7 | label_boi_a2/Accrued amortization | boi_met:mi346 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | N/A | boi_RP:x24 |
| r0.8 | label_boi_a2/Provision for decrease in value | boi_met:md348 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | N/A | boi_MU:x1 | boi_RP:x24 |
| 1.1 | Intellectual property rights (patents)/Avg. weighted amortization rate, pct. | boi_met:md353 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x869 | boi_MU:x1 | boi_RP:x24 |
| 1.2 | Intellectual property rights (patents)/Cost | boi_met:mi376 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x869 | N/A | boi_RP:x24 |
| 1.3 | Intellectual property rights (patents)/Accrued amortization | boi_met:mi346 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x869 | N/A | boi_RP:x24 |
| 1.4 | Intellectual property rights (patents)/Provision for decrease in value | boi_met:md348 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x869 | boi_MU:x1 | boi_RP:x24 |
| 1.5 | Intellectual property rights (patents)/Avg. weighted amortization rate, pct. | boi_met:md353 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_MC:x869 | boi_MU:x1 | boi_RP:x24 |
| 1.6 | Intellectual property rights (patents)/Cost | boi_met:mi376 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_MC:x869 | N/A | boi_RP:x24 |
| 1.7 | Intellectual property rights (patents)/Accrued amortization | boi_met:mi346 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_MC:x869 | N/A | boi_RP:x24 |
| 1.8 | Intellectual property rights (patents)/Provision for decrease in value | boi_met:md348 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_MC:x869 | boi_MU:x1 | boi_RP:x24 |
| 2.1 | Rights and use of customer databases/Avg. weighted amortization rate, pct. | boi_met:md353 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x870 | boi_MU:x1 | boi_RP:x24 |
| 2.2 | Rights and use of customer databases/Cost | boi_met:mi376 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x870 | N/A | boi_RP:x24 |
| 2.3 | Rights and use of customer databases/Accrued amortization | boi_met:mi346 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x870 | N/A | boi_RP:x24 |
| 2.4 | Rights and use of customer databases/Provision for decrease in value | boi_met:md348 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x870 | boi_MU:x1 | boi_RP:x24 |
| 2.5 | Rights and use of customer databases/Avg. weighted amortization rate, pct. | boi_met:md353 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_MC:x870 | boi_MU:x1 | boi_RP:x24 |
| 2.6 | Rights and use of customer databases/Cost | boi_met:mi376 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_MC:x870 | N/A | boi_RP:x24 |
| 2.7 | Rights and use of customer databases/Accrued amortization | boi_met:mi346 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_MC:x870 | N/A | boi_RP:x24 |
| 2.8 | Rights and use of customer databases/Provision for decrease in value | boi_met:md348 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_MC:x870 | boi_MU:x1 | boi_RP:x24 |
| 3.1 | Other amortizable expenses/Avg. weighted amortization rate, pct. | boi_met:md353 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x871 | boi_MU:x1 | boi_RP:x24 |
| 3.2 | Other amortizable expenses/Cost | boi_met:mi376 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x871 | N/A | boi_RP:x24 |
| 3.3 | Other amortizable expenses/Accrued amortization | boi_met:mi346 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x871 | N/A | boi_RP:x24 |
| 3.4 | Other amortizable expenses/Provision for decrease in value | boi_met:md348 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x871 | boi_MU:x1 | boi_RP:x24 |
| 3.5 | Other amortizable expenses/Avg. weighted amortization rate, pct. | boi_met:md353 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_MC:x871 | boi_MU:x1 | boi_RP:x24 |
| 3.6 | Other amortizable expenses/Cost | boi_met:mi376 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_MC:x871 | N/A | boi_RP:x24 |
| 3.7 | Other amortizable expenses/Accrued amortization | boi_met:mi346 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_MC:x871 | N/A | boi_RP:x24 |
| 3.8 | Other amortizable expenses/Provision for decrease in value | boi_met:md348 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x1 | boi_MC:x871 | boi_MU:x1 | boi_RP:x24 |