Schedule I - Insurance Subsidiaries (Details) - Parent Company [Member] - USD ($) $ in Millions |
Dec. 31, 2020 |
Dec. 31, 2019 |
|---|---|---|
| Parent And Unregulated Subsidiaries [Member] | ||
| Investments in and Advances to Affiliates [Line Items] | ||
| Cash cash equivalents and short term investments | $ 50.0 | $ 156.0 |
| Regulated Insurance Subsidiaries [Member] | ||
| Investments in and Advances to Affiliates [Line Items] | ||
| Cash cash equivalents and short term investments | $ 101.1 | $ 107.3 |