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Employee Deferred Compensation Plan and Employee Stock Purchase Plan - Additional Information (Detail) (USD $)
In Thousands, except Share data, unless otherwise specified
 12 Months Ended 1 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Jun. 30, 2001
Jun. 30, 2011
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]          
Percentage contribution, compensation 100.00%us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent        
Matching percentage, employee contribution 5.00%us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent        
Company's contributions amount $ 1,445us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount $ 1,330us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount $ 982us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount    
Common stock under employee stock purchase plan, par value $ 0.10us-gaap_CommonStockParOrStatedValuePerShare $ 0.10us-gaap_CommonStockParOrStatedValuePerShare      
Shares of common stock purchased through the plan 47,213us-gaap_StockIssuedDuringPeriodSharesEmployeeStockOwnershipPlan 27,923us-gaap_StockIssuedDuringPeriodSharesEmployeeStockOwnershipPlan 40,116us-gaap_StockIssuedDuringPeriodSharesEmployeeStockOwnershipPlan    
Employee Stock Purchase Plan          
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]          
Number of common stock shares under employee stock purchase plan       1,000,000us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans
/ us-gaap_PlanNameAxis
= avd_EmployeeStockPurchasePlanMember		  
Common stock under employee stock purchase plan, par value       $ 0.10us-gaap_CommonStockParOrStatedValuePerShare
/ us-gaap_PlanNameAxis
= avd_EmployeeStockPurchasePlanMember		  
Employee stock purchase plan offering period January 1 and July 1 of each year        
Commons stock plan available for sale under plan         995,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
/ us-gaap_PlanNameAxis
= avd_EmployeeStockPurchasePlanMember
Available common stock under plan 854,007us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
/ us-gaap_PlanNameAxis
= avd_EmployeeStockPurchasePlanMember		 901,220us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
/ us-gaap_PlanNameAxis
= avd_EmployeeStockPurchasePlanMember