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SEGMENT AND RELATED INFORMATION - Reportable Segments (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Net sales	$ 217.7	$ 235.8	$ 231.2	$ 212.2	$ 194.5	$ 204.4	$ 202.7	$ 190.2	$ 896.9	$ 791.8	$ 753.1
Depreciation and amortization									4.5	4.6	4.5
Operating Income (Loss)									61.7	45.7	8.0
Assets	530.0				551.4				530.0	551.4	566.1
Operating Segments \| IPG
Segment Reporting Information [Line Items]
Net sales									896.9	791.8	715.6
Depreciation and amortization									3.9	3.9	3.6
Operating Income (Loss)									82.6	69.6	34.3
Assets	234.7				220.4				234.7	220.4	201.5
Operating Segments \| ETG - discontinued
Segment Reporting Information [Line Items]
Assets	0.0				185.3				0.0	185.3	269.4
Operating Segments \| NATG
Segment Reporting Information [Line Items]
Operating Income (Loss)									(0.8)	(0.6)	(2.8)
Assets	8.9				13.6				8.9	13.6	6.9
Corporate and Other
Segment Reporting Information [Line Items]
Net sales									0.0	0.0	37.5
Depreciation and amortization									0.6	0.7	0.9
Operating Income (Loss)									(20.1)	(23.3)	(23.5)
Assets	$ 286.4				$ 132.1				$ 286.4	$ 132.1	$ 88.3