| r0.1 | label_boi_a2/Not accruing interest income | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x8 | boi_RP:x24 | N/A | boi_ST:x212 | N/A | N/A |
| r0.2 | label_boi_a2/Accruing, in arrears of 90 days or more | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x8 | boi_RP:x24 | N/A | boi_ST:x215 | N/A | boi_TI:x2 |
| r0.3 | label_boi_a2/Accruing, in arrears of 30 to 89 days | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x8 | boi_RP:x24 | N/A | boi_ST:x218 | N/A | boi_TI:x1 |
| r0.4 | label_boi_a2/Accruing | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x8 | boi_RP:x24 | N/A | boi_ST:x1 | N/A | boi_TI:x4 |
| r0.5 | label_boi_a2/Total | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x8 | boi_RP:x24 | N/A | boi_ST:x2 | N/A | N/A |
| 9.1 | Debts that have been recycled and classified again as problematic debts/Not accruing interest income | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x8 | boi_RP:x24 | boi_SE:x16 | boi_ST:x212 | boi_ST:x25 | N/A |
| 9.2 | Debts that have been recycled and classified again as problematic debts/Accruing, in arrears of 90 days or more | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x8 | boi_RP:x24 | boi_SE:x16 | boi_ST:x215 | boi_ST:x25 | boi_TI:x2 |
| 9.3 | Debts that have been recycled and classified again as problematic debts/Accruing, in arrears of 30 to 89 days | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x8 | boi_RP:x24 | boi_SE:x16 | boi_ST:x218 | boi_ST:x25 | boi_TI:x1 |
| 9.4 | Debts that have been recycled and classified again as problematic debts/Accruing | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x8 | boi_RP:x24 | boi_SE:x16 | boi_ST:x1 | boi_ST:x25 | boi_TI:x4 |
| 9.5 | Debts that have been recycled and classified again as problematic debts/Total | boi_met:mi1 | xbrli:monetaryItemType | instant | boi_BC:x1 | boi_CS:x2 | boi_MC:x8 | boi_RP:x24 | boi_SE:x16 | boi_ST:x2 | boi_ST:x25 | N/A |