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

X

- Definition

Cost method ownership percentage.

+ References

No definition available.

+ Details

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Namespace Prefix:	avd_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- 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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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- 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

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Namespace Prefix:
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