Restructuring and other charges (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Sep. 30, 2014
Restructuring Cost and Reserve [Line Items]
Other charges	$ 4.9	$ 0.2	$ 6.6	$ 9.1
Asset Impairment Charges			0.0	11.6
Net sales	310.1	$ 301.0	$ 836.4	853.1
Statesboro [Member]
Restructuring Cost and Reserve [Line Items]
Other charges	$ 3.6
Quebec [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring				7.2
Asset Impairment Charges				2.5
Environmental Remediation Expense				2.3
Severance Costs				$ 2.4
Net sales					$ 11.5