Stock-Based Compensation Plans (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2020 |
Mar. 31, 2019 |
|
| Stock based compensation plans: | ||
| Stock-based compensation expense | $ 4.6 | $ 2.8 |
| Tax benefits from stock-based compensation expense | $ 1.1 | $ 0.7 |
| Grants in period, options (in shares) | 0 | 0 |
| Convertible senior notes, net | ||
| Stock based compensation plans: | ||
| Repayments of debt | $ 89.0 | $ 7.8 |
| Restricted stock | ||
| Stock based compensation plans: | ||
| Grants in period, other than options (in shares) | 3,069 | 357,465 |
| Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period | 377,534 | 0 |
| Performance and market-based stock | ||
| Stock based compensation plans: | ||
| Grants in period, other than options (in shares) | 139,191 | 105,543 |