Share-Based Employee Compensation - Summary of Share-based Compensation Expenses Recognized (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] | |||
| Share-based compensation | $ 95.5 | $ 74.6 | $ 91.1 |
| Servicing [Member] | |||
| Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] | |||
| Share-based compensation | 17.1 | 13.8 | 18.3 |
| Marketing and sales [Member] | |||
| Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] | |||
| Share-based compensation | 6.6 | 3.2 | 5.9 |
| Technology and development [Member] | |||
| Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] | |||
| Share-based compensation | 52.9 | 44.6 | 52.8 |
| General and administrative [Member] | |||
| Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] | |||
| Share-based compensation | $ 18.9 | $ 13.0 | $ 14.1 |