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Exposure to Workers Compensation Claims, Per Incident

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Finite-Lived Tangible Asset Useful Life

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Income Tax Benefit, Likelihood of Realization Threshold

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Workers Compensation Undiscounted Basis Liability

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The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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The amount of net gain (loss) reclassified into earnings when interest rate cash flow hedge is discontinued because it is probable that the original forecasted transactions will not occur by the end of the original period or an additional two month time period.

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The expense charged against earnings for the period pertaining to standard and extended warranties on the entity's goods and services granted to customers.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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Carrying value as of the balance sheet date of obligations and payables pertaining to claims incurred of a workers compensation nature.

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Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2015
Gain (Loss) on Discontinuation of Interest Rate Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net	$ 0.0	$ 0.0	$ 2.4
Product Warranty Expense	2.6	3.9	18.7
Asset Retirement Obligation	3.8	4.5
Exposure to Workers Compensation Claims, Per Incident	1.0
Discontinued Operations, Receivable from Buyer of Discontinued Operation				$ 11.8
Workers Compensation Undiscounted Basis Liability	7.2	8.7
Workers' Compensation Liability	$ 6.2	$ 7.6
Income Tax Benefit, Likelihood of Realization Threshold	50.00%
Debt Issuance Costs, Net	$ 6.2
Minimum [Member]
Finite-Lived Tangible Asset, Useful Life, Maximum		3 years
Maximum [Member]
Finite-Lived Tangible Asset, Useful Life, Maximum		10 years
Land Improvements [Member] \| Minimum [Member]
Property, Plant and Equipment, Useful Life, Minimum	10 years
Land Improvements [Member] \| Maximum [Member]
Property, Plant and Equipment, Useful Life, Minimum	20 years
Building [Member] \| Minimum [Member]
Property, Plant and Equipment, Useful Life, Minimum	10 years
Building [Member] \| Maximum [Member]
Property, Plant and Equipment, Useful Life, Minimum	40 years
Machinery and Equipment [Member] \| Minimum [Member]
Property, Plant and Equipment, Useful Life, Minimum	3 years
Machinery and Equipment [Member] \| Maximum [Member]
Property, Plant and Equipment, Useful Life, Minimum	15 years
Software and Software Development Costs [Member] \| Maximum [Member]
Property, Plant and Equipment, Useful Life, Minimum	6 years
U.S. Pipe [Member] \| Maximum [Member]
Discontinued Operations, Receivable from Buyer of Discontinued Operation	$ 2.3
Other Current Assets [Member] \| U.S. Pipe [Member]
Discontinued Operations, Receivable from Buyer of Discontinued Operation	0.4
Other Noncurrent Assets [Member] \| U.S. Pipe [Member]
Discontinued Operations, Receivable from Buyer of Discontinued Operation	1.9
Revolving Credit Facility [Member]
Debt Issuance Costs, Net	1.3
Secured Debt [Member]
Debt Issuance Costs, Net	4.9	$ 5.8
Unsecured Debt [Member]
Debt Issuance Costs, Net	$ 4.9
Product Concentration Risk [Member]
Product Warranty Expense			$ 14.1