Description of Business and Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2018 USD ($) country reporting_unit	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Organization And Nature Of Business [Line Items]
Number of countries in which the company has production facilities | country		17
Impairment of intangible assets				$ 6,568,000
Impairment of goodwill		$ 0	$ 0	0
Impairments of indefinite-lived intangible assets		$ 0	0
Minimum number of entity's reporting units where the estimated fair value could be affected by changes to discount rate and the forecasted profitability | reporting_unit		1
Advertising costs		$ 4,300,000	$ 3,400,000	2,800,000
Tax benefit sustainable		greater than 50%
Minimum [Member]
Organization And Nature Of Business [Line Items]
Amortization period		7 years
Royalty rate indication based on return as a percentage of revenue		1.00%
Maximum [Member]
Organization And Nature Of Business [Line Items]
Amortization period		29 years
Royalty rate indication based on return as a percentage of revenue		2.00%
Changzhou China [Member] | Building
Organization And Nature Of Business [Line Items]
Impairment of assets				$ 900,000
Impairment of intangible assets	$ 6,600,000
Notes [Member]
Organization And Nature Of Business [Line Items]
Debt		$ 400,000,000
Estimated fair value		397,000,000
Altra Credit Agreement [Member]
Organization And Nature Of Business [Line Items]
Debt		$ 1,320,000,000