Restructuring, Asset Impairment, and Transition Expenses - Summary of Reconciliation of Restructuring Expense by Segment (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restructuring Cost And Reserve [Line Items]
Restructuring expense	$ 3.0	$ 7.4	$ 14.1
Operating Segments [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expense	3.0	7.4	14.1
Operating Segments [Member] | Power Transmission Technologies [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expense	1.8	4.7	6.5
Operating Segments [Member] | Automation & Specialty [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expense	1.2	2.7	7.6
2017 Altra Plan [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expense	0.0	0.5	5.7
2017 Altra Plan [Member] | Operating Segments [Member] | Power Transmission Technologies [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expense		0.5	5.7
2019 Altra Plan [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expense	3.0	6.9	8.4
2019 Altra Plan [Member] | Operating Segments [Member] | Power Transmission Technologies [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expense	1.8	4.2	0.8
2019 Altra Plan [Member] | Operating Segments [Member] | Automation & Specialty [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expense	$ 1.2	$ 2.7	$ 7.6