Restructuring - Additional Information (Detail) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2017 USD ($) Person	Mar. 31, 2016 USD ($)	Dec. 31, 2016 Person
Restructuring Cost and Reserve [Line Items]
Number of employees | Person	200		650
Total restructuring costs	$ 20.9	$ 0.5
Water Unit [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees | Person	100		300
Total restructuring costs	$ 7.1	(0.6)
Electrical Unit [Member]
Restructuring Cost and Reserve [Line Items]
Number of employees | Person	100		350
Total restructuring costs	$ 9.3	0.2
Corporate and Other [Member]
Restructuring Cost and Reserve [Line Items]
Total restructuring costs	$ 4.5	$ 0.9