Acquisition and Strategic Transaction Details - Transaction Expenses - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Business Combinations [Abstract]
Strategic transaction expenses	$ 18.0	$ 12.4	$ 37.8	$ 33.5