Cost-Reduction Actions - Individual Components of Work Force Reduction and Idle Lease Cost (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2019
Restructuring Reserve [Roll Forward]
Changes in estimates	$ 0.7		$ (2.2)
Work-force Reductions
Restructuring Reserve [Roll Forward]
Balance at beginning of period		$ 86.2
Payments		(28.8)
Changes in estimates		0.8
Translation adjustments		(0.6)
Balance at end of period		57.6
2019 remaining six months		44.5
Beyond 2019		44.5
Work-force Reductions | Forecast
Restructuring Reserve [Roll Forward]
2019 remaining six months				$ 13.1
Beyond 2019				13.1
Work-force Reductions | U.S.
Restructuring Reserve [Roll Forward]
Balance at beginning of period		6.1
Payments		(1.6)
Changes in estimates		(0.6)
Translation adjustments		0.0
Balance at end of period		3.9
2019 remaining six months		3.5
Beyond 2019		3.5
Work-force Reductions | U.S. | Forecast
Restructuring Reserve [Roll Forward]
2019 remaining six months				0.4
Beyond 2019				0.4
Work-force Reductions | International
Restructuring Reserve [Roll Forward]
Balance at beginning of period		80.1
Payments		(27.2)
Changes in estimates		1.4
Translation adjustments		(0.6)
Balance at end of period		53.7
2019 remaining six months		41.0
Beyond 2019		$ 41.0
Work-force Reductions | International | Forecast
Restructuring Reserve [Roll Forward]
2019 remaining six months				12.7
Beyond 2019				$ 12.7