CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Net sales	$ 609.9	$ 572.2	$ 1,738.8	$ 1,539.7
Cost of sales	486.7	476.2	1,416.9	1,272.3
Gross profit	123.2	96.0	321.9	267.4
Selling, general and administrative expenses	50.0	50.3	148.3	138.1
Operating income	73.2	45.7	173.6	129.3
Interest expense	(7.1)	(7.5)	(20.3)	(22.0)
Other income (expense), net	1.9	(0.5)	0.1	(0.7)
Income before income taxes	68.0	37.7	153.4	106.6
Income tax expense (benefit)	16.9	7.5	35.3	(39.1)
Net income	$ 51.1	$ 30.2	$ 118.1	$ 145.7
EARNINGS PER COMMON SHARE:
Basic (in dollars per share)	$ 1.06	$ 0.63	$ 2.45	$ 3.06
Diluted (in dollars per share)	$ 1.05	$ 0.63	$ 2.43	$ 3.04
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING:
Basic (in shares)	47.7	47.2	47.7	47.2
Diluted (in shares)	48.1	47.7	48.1	47.5
Cash dividends per common share (in dollars per share)	$ 0.20	$ 0.18	$ 0.60	$ 0.54