Retirement Plans (Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Payment for Pension and Other Postretirement Benefits	$ 1.0
Defined Benefit Plan, Service Cost	0.4	$ 0.4	$ 0.8	$ 0.9
Defined Benefit Plan, Interest Cost	3.5	3.6	7.0	7.2
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(4.0)	(4.1)	(8.1)	(8.3)
Amortization of actuarial net loss	0.5	0.8	1.0	1.6
Curtailment/special settlement loss (gain)	1.0	0.0	1.0	0.0
Defined Benefit Plan, Net Periodic Benefit Cost other than Service Cost	1.0	0.3	0.9	0.5
Net periodic benefit cost	1.4	$ 0.7	1.7	$ 1.4
Multiemployer Plans, Withdrawal Obligation	$ 1.1		$ 1.1