CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 224.7	$ 40.4	$ (32.6)
Other comprehensive income (loss):
Foreign currency translation	(3.0)	8.2	(4.9)
Total comprehensive income (loss)	$ 221.7	$ 48.6	$ (37.5)