Other Assets, Net - Components of Other Assets (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Other Assets [Abstract]
Amortization expense	$ 16.0	$ 21.3	$ 32.6	$ 40.8