Reconciliation of Unrecognized Tax Benefits (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Uncertain tax benefits accrued, beginning balance	$ 4.0	$ 3.9
Additions for tax positions related to current year	0.0	0.3
Additions for tax positions of prior years	1.0	0.0
Reductions for tax positions of prior years	0.0	0.0
Lapse of statute of limitations	(0.3)	(0.2)
Settlements	0.0	0.0
Uncertain tax benefits accrued, ending balance	$ 4.7	$ 4.0