Commitments and Contingencies - Narrative (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]
Operating lease expense		$ 8.4	$ 8.1	$ 7.7
Pretax liability expense (benefit) related to the non-income tax matters		(0.8)		0.2
Taxes paid to settle with certain states		$ 1.4		$ 0.1
Settlement					$ 0.8
Payments for legal settlement	$ 0.8