Employee Benefit Plans (Narrative) (Details) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
|
Jun. 30, 2020
USD ($)
pension_plan
|
Jun. 30, 2019
USD ($)
|
Jun. 30, 2020
USD ($)
pension_plan
|
Jun. 30, 2019
USD ($)
|
|
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||
| Defined Contribution Plan, Cost | $ | $ 2.4 | $ 2.4 | $ 6.9 | $ 6.5 |
| Number Of Sponsored Pension Plans | pension_plan | 2 | 2 | ||
| Number Of Sponsored Pension Plans, Non-Union Employees | pension_plan | 1 | 1 | ||
| Number Of Sponsored Pension Plans, Union Employees | pension_plan | 1 | 1 | ||
| Pension Plan [Member] | ||||
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||
| Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year | $ | $ 29.3 | $ 29.3 | ||
| Other Postretirement Benefits Plan [Member] | ||||
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||||
| Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year | $ | $ 0.7 | $ 0.7 | ||