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Cost Method Investment - Additional Information (Detail) - Bi-PA - USD ($) | Dec. 31, 2018 | Dec. 31, 2017
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Equity Method Investments [Line Items] |  |
Cost method ownership percentage | 15.00% | 15.00%
Cost-method Investments, Impairment | $ 0 | $ 0

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- Definition Cost method ownership percentage. + References No definition available. + Details
Name: | avd_CostMethodOwnershipPercentage
Namespace Prefix: | avd_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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- Definition Amount of cumulative impairment loss on investment in equity security without readily determinable fair value. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84241550&loc=SL75117539-209714 + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=avd_BiPaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |