DISPOSITIONS AND SPECIAL CHARGES - Discontinued Operations (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss from discontinued operations, net of tax	$ (35.7)	$ (49.5)	$ (75.8)
Net loss per share - basic and diluted (in dollars per share)	$ (0.96)	$ (1.33)	$ (2.04)
NATG | Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales	$ 117.0	$ 521.6	$ 1,664.6
Cost of sales	102.9	461.6	1,516.8
Gross profit	14.1	60.0	147.8
Selling, distribution and administrative expenses	22.1	96.9	221.0
Special charges, net	30.6	11.5	2.6
Operating loss from discontinued operations	(38.6)	(48.4)	(75.8)
Foreign currency exchange loss	0.8	0.0	1.8
Interest and other expense (income), net	0.0	0.3	0.3
Loss of discontinued operations before income taxes	(39.4)	(48.7)	(77.9)
Provision (benefit) for income tax	(3.7)	0.8	(2.1)
Loss from discontinued operations, net of tax	$ (35.7)	$ (49.5)	$ (75.8)