Employee Benefits (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Curtailment loss	$ (1.2)	$ (0.1)
Defined Benefit Plan, Accumulated Benefit Obligation	135.2	122.1
401(k) Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan, Employer Discretionary Contribution Amount	3.6	5.8	$ 6.0
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer	5.0
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	$ 4.0
Pension Plan [Member] | Active Employees [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Number of Employees Covered	4
Defined Benefit Plan, Percentage Of Employees Covered	2.00%
Pension Plan [Member] | Non-active Employees [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Number of Employees Covered	210
SERP [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 0.5
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	$ 8.6
Medical Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Number of Eligible	1
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 0.9	0.4
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	0.2
Defined Benefit Plan, Curtailment loss	(0.8)	(0.2)	0.0
Defined Benefit Plan, Expected Amortization, Next Fiscal Year	$ 0.1
Medical Plan [Member] | Non-active Employees [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Number of Employees Enrolled	33
Pension Plan and SERP [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 5.5	5.7
Defined Benefit Plan, Curtailment loss	2.0	$ 0.3	$ 0.7
Defined Benefit Plan, Expected Amortization, Next Fiscal Year	$ 0.8