Available-for-sale Securities - Fair Value of Debt Securities Reported Less Than Their Historical Cost (Details) - USD ($) $ in Millions |
Jun. 30, 2026 |
Jun. 30, 2025 |
|---|---|---|
| Available-for-sale Securities | ||
| Fair value of certain investments reported less than their historical cost | $ 253.8 | $ 264.5 |
| Certain investments in debt securities reported at less than historical cost, percentage of Company's AFS portfolio | 56.30% | 57.40% |