Segments, Concentrations and Geographic Information - Segment Financial Information and Reconciliation of Segments Revenue to Unaudited Condensed Consolidated Revenue (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales		$ 482.8	$ 240.4
Income from operations		66.4	19.7
Restructuring costs		(2.3)	(0.9)
Loss on settlement of pension plan			5.1
Net interest expense		19.8	1.8
Other non-operating (income), net		1.1	(0.1)
Total other non-operating (income) expense, net		20.9	6.8
Income before income taxes		45.5	12.9
Provision for income taxes		10.3	3.9
Net income		35.2	9.0
Operating Segments [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Restructuring costs		(2.3)	(0.9)
Operating Segments [Member] | Power Transmission Technologies [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales		234.9	240.4
Income from operations		28.9	28.2
Restructuring costs		(1.0)
Operating Segments [Member] | Automation & Specialty [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales		249.1
Income from operations		40.6
Restructuring costs		(1.3)
Intersegment Eliminations [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales		(1.2)
Corporate [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Income from operations	[1]	$ (0.8)	$ (7.6)

[1] Certain expenses are maintained at the corporate level and not allocated to the segments. These include various administrative expenses related to the Company’s corporate headquarters, depreciation on capitalized software costs, non-capitalizable software implementation costs and acquisition related expenses.