Mergers and Acquisitions - Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Business Combinations [Abstract]
Revenue	$ 386.7	$ 397.2	$ 1,157.5	$ 1,194.6
Net loss applicable to common shareholders	$ (20.3)	$ (100.9)	$ (57.0)	$ (62.8)
Earnings per share:
Basic and diluted loss per common share	$ (0.41)	$ (2.02)	$ (1.27)	$ (1.26)