Revenue Recognition - Disaggregates Revenue for Each Reportable Segment and Geographic Region (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation Of Revenue [Line Items]
Net sales	$ 466.5	$ 237.3	$ 949.3	$ 477.7
North America (primarily U.S.) [Member]
Disaggregation Of Revenue [Line Items]
Net sales	269.8	119.0	542.8	244.7
Europe Excluding Germany [Member]
Disaggregation Of Revenue [Line Items]
Net sales	79.9	42.5	161.7	86.6
Germany [Member]
Disaggregation Of Revenue [Line Items]
Net sales	56.8	48.8	119.0	98.2
Asia And Other [Member]
Disaggregation Of Revenue [Line Items]
Net sales	60.0	27.0	125.8	48.2
Operating Segments [Member] | Power Transmission Technologies [Member]
Disaggregation Of Revenue [Line Items]
Net sales	234.9	$ 237.3	469.8	$ 477.7
Operating Segments [Member] | Automation & Specialty [Member]
Disaggregation Of Revenue [Line Items]
Net sales	233.3		482.4
Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Net sales	$ (1.7)		$ (2.9)