Long-Term Debt - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Principal payments on long -term debt due in 2022	$ 53,300,000
Senior Secured Revolving Line Of Credit
Debt Instrument [Line Items]
Aggregate principal amount	$ 275,000,000
Credit agreement, covenant description	The Credit Agreement consists of a line of credit of up to $275,000, an accordion feature of up to $150,000, a letter of credit and swingline sub-facility (each having limits of $25,000) and has a maturity date of August 5, 2026. The Credit Agreement amends and restates the previous credit facility, which had a maturity date of June 30, 2022. With respect to key financial covenants, the Credit Agreement contains two: namely, borrowers are required to maintain a Total Leverage (“TL”) Ratio of no more than 3.5-to-1, during the first three years, stepping down to 3.25-to-1 as of September 30, 2024, and a Fixed Charge Coverage Ratio of at least 1.25-to-1. In addition, to the extent that it completes acquisitions totaling $15 million or more in any 90-day period, AMVAC may step-up the TL Ratio by 0.5-to-1, not to exceed 4.00-to-1, for the next three full consecutive quarters.
Consolidated funded debt ratio	3.25%
Senior secured credit facility, maturity date	Aug. 05, 2026
Credit agreement, variable rate description	Under the Credit Agreement, revolving loans bear interest at a variable rate based, at borrower’s election with proper notice, on either (i) LIBOR plus the “Applicable Margin” which is based upon the Total Leverage (“TL”) Ratio (“LIBOR Revolver Loan”) or (ii) the greater of (x) the Prime Rate, (y) the Federal Funds Rate plus 0.5%, and (z) the Daily One-Month LIBOR Rate plus 1.00%, plus, in the case of (x), (y) or (z) the Applicable Margin (“Adjusted Base Rate Revolver Loan”). Interest payments for LIBOR Revolver Loans are payable on the last day of each interest period (either one-, three- or six- months, as selected by the borrower)
Credit agreement, interest rate	1.98%
Senior Secured Revolving Line Of Credit | Fed Funds Effective Rate Overnight Index Swap Rate
Debt Instrument [Line Items]
Credit agreement, variable rate basis	0.50%
Senior Secured Revolving Line Of Credit | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Credit agreement, variable rate basis	1.00%
Senior Secured Revolving Line Of Credit | Base Rate
Debt Instrument [Line Items]
Credit agreement, interest payment period, description	last business day of each
Senior Secured Revolving Line Of Credit | Term Loan
Debt Instrument [Line Items]
Accordion feature	$ 150,000,000
Senior Secured Revolving Line Of Credit | Credit Agreement
Debt Instrument [Line Items]
Available borrowings capacity under credit agreement		$ 86,736,000
Consolidated funded debt ratio	0.50%
Maximum | Senior Secured Revolving Line Of Credit
Debt Instrument [Line Items]
Available borrowings capacity under credit agreement	$ 25,000,000
Consolidated funded debt ratio	3.50%
Maximum | Senior Secured Revolving Line Of Credit | Credit Agreement
Debt Instrument [Line Items]
Consolidated funded debt ratio	4.00%
Joint venture, consideration	$ 50,000,000
Capacity to increase borrowings under credit agreement	$ 178,705,000
Minimum | Senior Secured Revolving Line Of Credit
Debt Instrument [Line Items]
Consolidated funded debt ratio	1.25%
Minimum | Senior Secured Revolving Line Of Credit | Credit Agreement
Debt Instrument [Line Items]
Joint venture, consideration	$ 15,000