Derivatives and Hedging Activities - Summary of effect of derivative instruments on income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Net sales	$ 573.0	$ 556.5	$ 1,158.4	$ 1,128.9
Cost of sales	460.4	449.5	933.1	930.2
Interest expense	5.3	7.0	10.7	13.2
Amount of gain reclassified from AOCI to income	3.0	0.6	8.3	(1.0)
Net sales
Derivative Instruments, Gain (Loss) [Line Items]
Total gain	0.1	0.3	0.6	0.6
Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Total gain	2.8	0.2	7.5	(1.8)
Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Total gain	0.1	0.1	0.2	0.2
Commodity contracts | Net sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain reclassified from AOCI to income	0.0	0.0	0.0	0.0
Commodity contracts | Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain reclassified from AOCI to income	2.8	0.2	7.5	(1.8)
Commodity contracts | Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain reclassified from AOCI to income	0.0	0.0	0.0	0.0
Foreign currency forward contracts | Net sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain reclassified from AOCI to income	0.1	0.3	0.6	0.6
Foreign currency forward contracts | Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain reclassified from AOCI to income	0.0	0.0	0.0	0.0
Foreign currency forward contracts | Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain reclassified from AOCI to income	0.0	0.0	0.0	0.0
Interest Rate Swaps | Net sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain reclassified from AOCI to income	0.0	0.0	0.0	0.0
Hedged Item	0.0	0.0	0.0	0.0
Derivatives designated as hedging instruments	0.0	0.0	0.0	0.0
Interest Rate Swaps | Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain reclassified from AOCI to income	0.0	0.0	0.0	0.0
Hedged Item	0.0	0.0	0.0	0.0
Derivatives designated as hedging instruments	0.0	0.0	0.0	0.0
Interest Rate Swaps | Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain reclassified from AOCI to income	0.1	0.1	0.2	0.2
Hedged Item	(0.1)	0.1	(0.1)	0.3
Derivatives designated as hedging instruments	$ 0.1	$ (0.1)	$ 0.1	$ (0.3)