Revenue Recognition - Disaggregates Revenue for Each Reportable Segment and Geographic Region (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation Of Revenue [Line Items]
Net sales	$ 472.1	$ 434.2
North America (primarily U.S.) [Member]
Disaggregation Of Revenue [Line Items]
Net sales	247.0	245.3
Europe Excluding Germany [Member]
Disaggregation Of Revenue [Line Items]
Net sales	84.9	74.8
Germany [Member]
Disaggregation Of Revenue [Line Items]
Net sales	51.0	52.5
China [Member]
Disaggregation Of Revenue [Line Items]
Net sales	64.1	38.4
Asia and Other Excluding China [Member]
Disaggregation Of Revenue [Line Items]
Net sales	25.1	23.2
Operating Segments [Member] | Power Transmission Technologies [Member]
Disaggregation Of Revenue [Line Items]
Net sales	221.0	216.7
Operating Segments [Member] | Automation & Specialty [Member]
Disaggregation Of Revenue [Line Items]
Net sales	252.1	218.6
Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Net sales	$ (1.0)	$ (1.1)