Restructuring Costs - Summary of Reconciliation of Restructuring Expense by Segment (Detail) - USD ($)	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Restructuring Cost And Reserve [Line Items]
Restructuring expense	$ 3,900,000	$ 500,000	$ 400,000	$ 700,000	$ 800,000	$ 900,000	$ 4,800,000	$ 2,400,000
2017 Altra Plan [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expense							0
2019 Altra Plan [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expense	3,900,000	$ 500,000	$ 400,000	700,000	$ 800,000	$ 900,000	4,800,000	2,400,000
Operating Segments [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expense	3,900,000			700,000			4,800,000	2,400,000
Operating Segments [Member] | Power Transmission Technologies [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expense	3,900,000			400,000			4,100,000	1,400,000
Operating Segments [Member] | Automation & Specialty [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expense				300,000			700,000	1,000,000.0
Operating Segments [Member] | 2019 Altra Plan [Member] | Power Transmission Technologies [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expense	$ 3,900,000			400,000			4,100,000	1,400,000
Operating Segments [Member] | 2019 Altra Plan [Member] | Automation & Specialty [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expense				$ 300,000			$ 700,000	$ 1,000,000.0