Income Taxes - Taxable income and Taxable Net Realized Gains Losses (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2024 |
Jun. 30, 2023 |
Jun. 30, 2024 |
Jun. 30, 2023 |
|
| Income Tax Disclosure [Abstract] | ||||
| Taxable income | $ 75.9 | $ 60.9 | $ 154.2 | $ 125.0 |
| Taxable income, per share (in dollars per share) | $ 0.47 | $ 0.43 | $ 0.97 | $ 0.90 |
| Taxable net realized gains (losses) | $ 3.5 | $ 20.2 | $ 9.4 | $ 27.4 |
| Taxable net realized gains, per share (in dollars per share) | $ 0.02 | $ 0.14 | $ 0.06 | $ 0.20 |
| Weighted average shares outstanding (in shares) | 160,748 | 141,390 | 159,096 | 138,338 |