Supplemental Operations and Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Supplemental Operations Statement and Cash Flow Information [Line Items]
Advertising and promotion expense	$ 33.0	$ 19.9	$ 33.2
Repair and maintenance expense	0.6	0.4	0.3
Research and development expense	9.4	7.6	8.1
Interest paid	48.8	0.0	0.0
Income taxes paid	$ 10.1	0.3	$ 1.0
Difference between revenue guidance in effect before and after Topic 606
Supplemental Operations Statement and Cash Flow Information [Line Items]
Advertising and promotion expense		$ 7.6

Supplemental Operations Statement and Cash Flow Information

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The aggregate costs of keeping the property in good condition but that do not appreciably prolong the life or increase the value of the property.

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The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income.

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Amount of cash paid for interest, excluding capitalized interest, classified as operating activity. Includes, but is not limited to, payment to settle zero-coupon bond for accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount.

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The total expense recognized in the period for promotion, public relations, and brand or product advertising.

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The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

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