Pension and Postretirement Benefits (Components of net periodic benefit) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Pension Benefits
Components of net periodic benefit cost
Service costs	$ 0.6	$ 0.6
Interest costs	0.5	0.5
Expected return on plan assets	(2.4)	(2.4)
Recognized net actuarial loss	0.3	0.3
Net periodic benefit (income) costs	$ (1.0)	$ (1.0)
Discount rate, weighted average	3.91%	4.13%
Expected return on plan assets, weighted average	8.25%	8.25%
Postretirement Benefits
Components of net periodic benefit cost
Service costs	$ 0.0	$ 0.0
Interest costs	0.1	0.1
Expected return on plan assets	0.0	0.0
Recognized net actuarial loss	0.0	0.1
Net periodic benefit (income) costs	$ 0.1	$ 0.2
Discount rate, weighted average	3.63%	3.80%