Employee Benefits (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Labor-related expenses	$ 4.2	$ (0.9)	$ 5.0	$ 7.0
Pension expense	2.8	2.8	5.9	5.2
Restricted Stock And Stock Appreciation Rights SARS
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	3.7	7.7	11.9	9.1
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 0.1	$ 0.1	$ 0.2	$ 0.2