Discontinued Operations - Results of Discontinued Operations (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax expense (benefit)	$ (4.8)	$ (0.2)	$ (5.9)
Earnings (loss) from discontinued operations, net of tax	(3.9)	0.8	15.9
Shape Cutting Businesses [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue			30.2
Earnings from discontinued operations before income taxes			0.6
Gain on sale before tax			9.0
Income tax expense (benefit)			0
Earnings (loss) from discontinued operations, net of tax			9.6
Other [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue			0
Earnings from discontinued operations before income taxes			0.4
Gain on sale before tax			0
Income tax expense (benefit)			(5.9)
Earnings (loss) from discontinued operations, net of tax			6.3
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue			30.2
Earnings from discontinued operations before income taxes			1.0
Gain on sale before tax			9.0
Income tax expense (benefit)			(5.9)
Earnings (loss) from discontinued operations, net of tax			$ 15.9