Activity for Level Three Pension Plan Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits, Domestic
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	$ 268.5	$ 270.0
Acquisitions	292.5
Fair value of plan assets at end of year	517.5	268.5
Pension Benefits, Domestic | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	11.3	13.8
Acquisitions	36.0
Relating to assets held at year-end	(1.6)	0.7
Relating to assets sold during the period	0.1	0.2
Purchases, sales, settlements and other, net	(6.9)	(3.4)
Fair value of plan assets at end of year	38.9	11.3
Pension Benefits, Foreign
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	35.0	35.7
Fair value of plan assets at end of year	32.5	35.0
Pension Benefits, Foreign | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	15.5	17.3
Relating to assets held at year-end	0.4	0.4
Purchases, sales, settlements and other, net	(1.7)	(2.2)
Fair value of plan assets at end of year	$ 14.2	$ 15.5