Amounts Recognized In Consolidated Balance Sheets (Detail) - Pension Plans, Defined Benefit - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Other assets	$ 0.0	$ 7.2
Accrued compensation and benefits	(4.6)	(4.6)
Other long-term liabilities	(115.0)	(126.9)
Net amount recognized	$ (119.6)	$ (124.3)