Employee Benefits Schedule of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Pension Plan and SERP [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost		$ 0.3	$ 0.2
Interest cost		1.2	1.2
Expected return on plan assets		(1.3)	(1.4)
Amortization of prior service costs	[1]	0.3	0.2
Amortization of actuarial losses	[1]	0.3	0.1
Periodic expense		0.8	0.3
Medical Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost		0.0	0.1
Amortization of prior service costs	[1]	(0.1)	0.0
Periodic expense		$ (0.1)	$ 0.1

[1] Amortization of prior service costs and actuarial losses out of accumulated other comprehensive income are recognized on the Condensed Consolidated Statements of Operations within "Interest and other income (expense)".