Employee Benefits (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions by Employer	$ 2.5
Estimated Future Employer Contributions in Current Fiscal Year	2.5
SERP [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions by Employer	0.1
Estimated Future Employer Contributions in Current Fiscal Year	0.3
Medical Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions by Employer	0.1
Estimated Future Employer Contributions in Current Fiscal Year	0.1
401(k) Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions by Employer	1.8
Estimated Future Employer Contributions in Current Fiscal Year	3.1
Pension Plan Discretionary Contribution [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated Future Employer Contributions in Current Fiscal Year	0.1
Total [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension and Medical Plan curtailment	(0.5)	$ 0.0
Interest and other income (expense) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension and Medical Plan curtailment	(0.3)	0.0
Net gain (loss) from asset sales [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension and Medical Plan curtailment	$ (0.2)	$ 0.0