SEGMENT AND RELATED INFORMATION - Segments by Geographic Area (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
Revenues from External Customers and Long-Lived Assets [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
Long-lived assets	14.9				14.0				14.9	14.0	15.4
United States | Reportable Geographical Components
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									854.6	759.4	692.3
Long-lived assets	14.8				13.9				14.8	13.9	15.4
Germany | Reportable Geographical Components
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									0.0	0.0	33.9
Other North America | Reportable Geographical Components
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									42.3	32.4	26.9
Long-lived assets	$ 0.1				$ 0.1				$ 0.1	$ 0.1	$ 0.0