Changes in Accumulated Other Comprehensive Income by Component - Summary of Reclassifications Out of Accumulated Other Comprehensive Income (Detail) (Reclassification out of Accumulated Other Comprehensive Income [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013
Reclassification out of Accumulated Other Comprehensive Income [Member]
Pension and Post-retirement liabilities:
Amortization of loss reclassified into Selling, general and administrative expenses	$ 0.1	$ 0.1	$ 0.2	$ 0.2
Tax income	0	(0.1)	(0.1)	(0.1)
Amortization of loss net of tax	$ 0.1	$ 0	$ 0.1	$ 0.1