Revenue Recognition - Contract Balances (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2021 |
Dec. 31, 2020 |
|
| Revenue Recognition | ||
| Contract assets | $ 8.5 | $ 8.3 |
| Contract liabilities | 54.4 | $ 55.0 |
| Revenue recognized | 14.6 | |
| Contract liabilities increase due to cash received | 3.5 | |
| Contract assets reclassified into accounts receivable | 10.1 | |
| Contract modifications adjustment | $ 1.3 |