| In millions, except per share items | Dec-31-22 | Dec-05-22 | Dec-31-21 | Dec-05-21 | Dec-31-20 | Dec-05-20 | Dec-31-19 | Dec-31-18 |
| | 10-K | 8-K | 10-K | 8-K | 10-K | 8-K | 10-K | 10-K |
| Investment income | | | | | | | | |
| Interest income (excluding PIK) | | | | | | | | |
| PIK income | | | | | | | | |
| Dividend income | | | | | | | | |
| Lease income | | | | | | | | |
| Other income | | | | | | | | |
| Total investment income | 181.0 | | 165.1 | | 172.1 | | | |
| |
| Operating expenses | | | | | | | | |
| Professional fees | 1.8 | | 1.7 | | 1.8 | | | |
| Administrative expenses | 1.8 | | 1.9 | | 2.2 | | 2.3 | 2.4 |
| Insurance expense | 0.6 | | 0.6 | | 0.7 | | | |
| Other operating expenses | 2.6 | | 2.6 | | 2.6 | | 2.9 | 2.7 |
| Total operating expenses | 92.6 | 2.6 | 92.6 | 2.6 | 88.9 | 2.6 | 7.0 | 5.1 |
| Net investment income | 88.4 | 88.4 | 72.5 | 72.5 | 83.2 | 83.2 | 94.9 | 93.4 |
| |
| Net realized gain (loss): | | | | | | | | |
| Net realized gain (loss) | -213.6 | | 139.2 | | -24.3 | | | |
| |
| Net change in unrealized appreciation (depreciation): | | | | | | | | |
| Net change in unrealized appreciation (depreciation) | | | | | | | | |
| Net realized and unrealized gain (loss) | -213.6 | | 139.2 | | -24.3 | | | |
| Realized loss on extinguishment of debt | | | -6.2 | | -2.4 | | | |
| Net increase (decrease) in net assets resulting from operations | -9.2 | | 133.8 | | 71.4 | | | |
| |
| Basic earnings (loss) per share | ($0.16) | ($0.16) | $2.32 | $2.32 | $1.23 | $1.23 | $0.52 | $0.77 |
| Diluted earnings (loss) per share | ($0.16) | ($0.16) | $2.32 | $2.32 | $1.23 | $1.23 | $0.52 | $0.77 |
| |
| Basic weighted average common shares outstanding | 57.8 | 57.8 | 57.8 | 57.8 | 58.0 | 58.0 | 58.8 | 58.8 |
| Diluted weighted average common shares outstanding | 57.8 | | 57.8 | | 58.0 | | | |