Income Taxes - Schedule of Unrecognized Tax Benefits Roll Forward (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Uncertain tax positions, beginning of the year	$ 6.2	$ 0.8
Additions for tax positions of prior years	0.2	0.0
Additions for tax positions from acquisitions	6.1	5.8
Additions for tax positions taken during the current period	0.5	0.0
Reductions due to the statute of limitations	(1.5)	(0.4)
Uncertain tax positions, end of the year	$ 11.5	$ 6.2