Acquisition (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Feb. 29, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2012	Jun. 30, 2011
Acquisition and strategic partnership disclosures
Cash paid, net of cash acquired					$ 1.4
Additional disclosure
Acquisition-related costs			2.4		3.8
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
Decrease in amount allocated to goodwill	4.4
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	427.0
Additional disclosure
Acquisition-related costs						11.7	2.4
Transaction costs						5.2
Net sales		95.2		209.8
Operating income since acquisition		13.2		29.5
Proforma results
Revenue		533.5	531.7	1,078.5	1,074.0
Earnings		$ 33.0	$ 40.8	$ 72.2	$ 64.3
Earnings per Common Share, Basic (in dollars per share)		$ 0.62	$ 0.77	$ 1.36	$ 1.22
Earnings per Common Share, Diluted (in dollars per share)		$ 0.62	$ 0.77	$ 1.35	$ 1.21