Acquisition (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	0 Months Ended	1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Feb. 28, 2013	Feb. 29, 2012	Mar. 31, 2012	Mar. 31, 2012	Jun. 30, 2012	Jun. 30, 2011
Acquisition and strategic partnership disclosures
Cash paid, net of cash acquired				$ 12.9
Additional disclosure
Acquisition-related costs			7.9	11.7
Latrobe Acquisition
Acquisition and strategic partnership disclosures
Shares issued through business acquisition		8.1
Cash paid, net of cash acquired		11.5
Cash acquired		2.5
Summary of preliminary purchase price allocation
Accounts receivable		67.0
Inventory		242.6
Property, plant and equipment		172.4
Intangible assets		87.1
Other		9.8
Accounts Payable and accrued liabilities		(64.1)
Long-term debt		(153.7)
Pension and other postretirement liabilities		(100.8)
Deferred income taxes		(43.9)
Total identifiable net assets		216.4
Goodwill		210.6
Total purchase price, net of cash acquired and debt assumed		427.0
Impairment of goodwill	0
Additional disclosure
Goodwill recognized deductible for income tax purposes		0
Acquisition-related costs					11.7	2.4
Transaction costs					5.2
Net sales			42.0	42.0
Operating income since acquisition			5.1	5.1
Proforma results
Revenue			622.0	1,696.0
Earnings			$ 46.7	$ 104.0
Earnings per Common Share, Basic (in dollars per share)			$ 0.89	$ 1.98
Earnings per Common Share, Diluted (in dollars per share)			$ 0.88	$ 1.95