Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions		3 Months Ended
		Jun. 30, 2019	Jun. 30, 2018
Other comprehensive loss [Abstract]
Beginning balance		$ 533.9
Other comprehensive income (loss) before reclassifications		0.9	$ (24.2)
Reclassifications for amortization of unrecognized net loss	[1]	1.4	1.3
Reclassifications for realized gains - net	[2]	(0.1)
Income taxes		0.0	(0.4)
Total other comprehensive income (loss)		2.2	(23.3)
Ending balance		540.3
Accumulated Other Comprehensive Loss [Member]
Other comprehensive loss [Abstract]
Beginning balance		(178.4)	(140.3)
Ending balance		(176.2)	(163.6)
Foreign Currency Translation [Member]
Other comprehensive loss [Abstract]
Beginning balance		(42.6)	(5.5)
Other comprehensive income (loss) before reclassifications		1.9	(24.7)
Reclassifications for amortization of unrecognized net loss	[1]	0.0	0.0
Reclassifications for realized gains - net	[2]	0.0
Income taxes		0.0	0.0
Total other comprehensive income (loss)		1.9	(24.7)
Ending balance		(40.7)	(30.2)
Defined Benefit Plans [Member]
Other comprehensive loss [Abstract]
Beginning balance		(136.3)	(134.9)
Other comprehensive income (loss) before reclassifications		0.0	0.0
Reclassifications for amortization of unrecognized net loss	[1]	1.4	1.3
Reclassifications for realized gains - net	[2]	0.0
Income taxes		(0.3)	(0.3)
Total other comprehensive income (loss)		1.1	1.0
Ending balance		(135.2)	(133.9)
Cash Flow Hedges [Member]
Other comprehensive loss [Abstract]
Beginning balance		0.5	0.1
Other comprehensive income (loss) before reclassifications		(1.0)	0.5
Reclassifications for amortization of unrecognized net loss	[1]	0.0	0.0
Reclassifications for realized gains - net	[2]	(0.1)
Income taxes		0.3	(0.1)
Total other comprehensive income (loss)		(0.8)	0.4
Ending balance		$ (0.3)	$ 0.5

[1] Amounts are included in the calculation of net periodic benefit cost for the Company's defined benefit plans, which include pension and other postretirement plans. See Note 4 for additional information about the Company's pension plans.

[2] Amount represent net gains and losses associated with cash flow hedges that were  reclassified to net earnings.