Reclassifications from Accumulated Other Comprehensive (Loss) Income (AOCI) - Schedule of amounts reclassified from AOCI (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales	$ 460.4	$ 449.5	$ 933.1	$ 930.2
Net sales	573.0	556.5	1,158.4	1,128.9
Interest expense	5.3	7.0	10.7	13.2
Income before income taxes	50.5	45.2	104.6	85.5
Tax (expense) benefit	(11.7)	(9.7)	(24.6)	(18.5)
Net income	38.8	35.5	80.0	67.0
(Loss) gain	0.8	(3.2)	0.5	(1.7)
Amount Reclassified from AOCI | Cash flow hedging items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	3.0	0.6	8.3	(1.0)
Tax (expense) benefit	(0.7)	(0.1)	(2.0)	0.3
Net income	2.3	0.5	6.3	(0.7)
Amount Reclassified from AOCI | Net actuarial loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
(Loss) gain	(4.5)	(3.0)	(9.0)	(6.0)
Amount Reclassified from AOCI | Prior service benefit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
(Loss) gain	0.5	0.8	1.0	1.6
Amount Reclassified from AOCI | Pension and other postretirement benefit plan items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	(4.0)	(2.2)	(8.0)	(4.4)
Tax (expense) benefit	1.0	0.5	2.0	1.0
Net income	(3.0)	(1.7)	(6.0)	(3.4)
Amount Reclassified from AOCI | Commodity contracts | Cash flow hedging items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales	2.8	0.2	7.5	(1.8)
Amount Reclassified from AOCI | Foreign exchange contracts | Cash flow hedging items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net sales	0.1	0.3	0.6	0.6
Amount Reclassified from AOCI | Forward interest rate swaps | Cash flow hedging items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ 0.1	$ 0.1	$ 0.2	$ 0.2