Condensed Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Net Sales	$ 244.0	$ 185.8
Cost of goods sold	152.7	120.2
Gross Profit	91.3	65.6
Selling, general and administrative expenses	36.5	27.2
Amortization of intangible assets	5.5	5.5
Operating Profit	49.3	32.9
Interest expense, net	11.6	0.0
Earnings Before Income Taxes	37.7	32.9
Income tax expense	5.9	7.8
Net Earnings Including Redeemable Noncontrolling Interest	31.8	25.1
Less: Net earnings attributable to redeemable noncontrolling interest	25.8	25.1
Net Earnings Available to Class A Common Stockholders	$ 6.0	$ 0.0
Earnings per Class A Common Share, Basic (in usd per share)	$ 0.15
Earnings per Class A Common Share, Diluted (in usd per share)	$ 0.15
Weighted-Average Class A Common Shares Outstanding, Basic (in shares)	39.4
Weighted-Average Class A Common Shares Outstanding, Diluted (in shares)	39.4