Pension and Other Employee Benefits - Amounts Recognized in Accumulated Other Comprehensive Income (Loss) (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Compensation And Retirement Disclosure [Abstract]
Accumulated other comprehensive (loss) income, Net of tax	$ 0.8	$ 1.0	$ 0.6

Accumulated other comprehensive income loss defined benefit pension and other postretirement plans tax.

No definition available.

Name:	aimc_AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansTax
Namespace Prefix:	aimc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant