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Commitments and Contingencies (Details) $ in Millions, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2018 CAD ($)	Sep. 30, 2017 USD ($)
Loss Contingency, Damages Sought, Value				$ 10.0
Income Tax Examination, Penalties and Interest Expense		$ 22.0
Loss Contingency, Estimated Recovery from Third Party		17.0
Walter Tax Liability		$ 22.0	$ 0.0
Document Period End Date		Sep. 30, 2019
Product Warranty Expense		$ 3.9	18.7		$ 12.3
Operating Leases
Rent expense		5.8	6.4		5.8
Future minimum payment under non-cancelable operating leases, CY Plus 1		6.1
Future minimum payment under non-cancelable operating leases, CY Plus 2		5.1
Future minimum payment under non-cancelable operating leases, CY Plus 3		4.2
Future minimum payment under non-cancelable operating leases, CY Plus 4		3.8
Future minimum payment under non-cancelable operating leases, CY Plus 5		3.7
Future minimum payment under non-cancelable operating leases, CY plus 6 and up		$ 15.8
IRS-Walter Energy Claim 1 Total [Member]
Loss Contingency, Damages Sought, Value	$ 554.3
IRS-Walter Energy Claim 1 Priority [Member]
Loss Contingency, Damages Sought, Value	229.1
IRS-Walter Energy Claim 2 [Member]
Loss Contingency, Damages Sought, Value	860.4
IRS-Walter Energy Claim 2 Priority [Member]
Loss Contingency, Damages Sought, Value	$ 535.3
Product Concentration Risk [Member]
Product Warranty Expense			$ 14.1		$ 9.8

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