Income Taxes - Summary of Activity Related to Unrecognized Tax Benefits (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Jun. 30, 2019 |
Jun. 30, 2018 |
Jun. 30, 2017 |
|
| Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] | |||
| Beginning balance | $ 22.8 | $ 18.7 | $ 18.2 |
| Gross increase related to prior period tax positions | 17.3 | 3.5 | 0.6 |
| Gross increase related to current period tax positions | 2.8 | 3.0 | 2.7 |
| Gross decrease related to prior period tax positions | (2.6) | (2.4) | (2.8) |
| Ending balance | $ 40.2 | $ 22.8 | $ 18.7 |