Capital Stock - Schedule of Share-Based Compensation Expense (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Share-Based Compensation Expense [Line Items] | ||
| Share-based compensation expense | $ 2.8 | $ 13.4 |
| Impact of accelerated vesting on equity awards | (1.1) | 0.0 |
| Total share-based compensation expense | 1.7 | 13.4 |
| Stock Options | ||
| Share-Based Compensation Expense [Line Items] | ||
| Share-based compensation expense | 0.1 | 0.2 |
| Restricted Share Units and Other Share-based Compensation | ||
| Share-Based Compensation Expense [Line Items] | ||
| Share-based compensation expense | 2.5 | 13.0 |
| Share Appreciation Rights (SARs) | ||
| Share-Based Compensation Expense [Line Items] | ||
| Share-based compensation expense | $ 0.2 | $ 0.2 |