Restructuring Charges and Asset Impairment Charges - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring and asset impairment charges		$ 18.0	$ 29.1	$ 0.0
Restructuring charges and asset impairment charges		10.4
Non-cash impairment charges		7.6
Impairment of property plant and equipment	$ 6.5	6.5
Impairment of intangible assets		1.1
Effect on future earnings due to restructuring			30.0
Restructuring reserve		0.3	2.3	$ 0.0
Cash payments for restructuring		3.0	10.9
Special Termination Benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges and asset impairment charges		9.4
Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring charges and asset impairment charges		0.7	12.7
Other restructuring charges to be paid in future periods		$ 0.3
Restructuring reserve			2.5
Restructuring reserve related to pension plans			8.3
Non-cash forfeiture income			0.4
Material development program exit costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges and asset impairment charges			13.4
Non-cash impairment charges			5.4
Cash payments for restructuring			8.0
Site closure costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges and asset impairment charges			3.0
Impairment of property plant and equipment			2.6
Cash payments for restructuring			$ 0.4