Employee Stock and Incentive Plans - Employee Stock Ownership Plan (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Employee Stock Ownership Plan [Abstract] | |||
| ESOP Compensation Expense | $ 10.8 | $ 11.4 | $ 11.0 |