Segments, Concentrations and Geographic Information - Reconciliation of Segment Assets to Consolidated Assets (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Total depreciation and amortization		$ 32.2	$ 9.3	$ 64.3	$ 18.7
Total assets		4,357.8	906.6	4,357.8	906.6	$ 4,337.2
Corporate [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total depreciation and amortization		0.7	0.9	1.4	1.7
Total assets	[1]	98.3	22.6	98.3	22.6
Power Transmission Technologies [Member] | Operating Segments [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total depreciation and amortization		8.3	8.4	16.7	17.0
Total assets		1,089.2	$ 884.0	1,089.2	$ 884.0
Automation & Specialty [Member] | Operating Segments [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total depreciation and amortization		23.2		46.2
Total assets		$ 3,170.3		$ 3,170.3

[1] Corporate assets are primarily cash and cash equivalents, tax related asset accounts, certain capitalized software costs, and property, plant and equipment.