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Commitments and Contingencies - Additional Information (Detail) $ in Millions | Jun. 30, 2019 USD ($) EquityFund
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Contingencies And Commitments [Line Items] |
Number of private equity funds | EquityFund | 2
Commitments towards private equity funds | $ 7.7
Investment Commitments [Member] |
Contingencies And Commitments [Line Items] |
Aggregate investment committed in private equity funds | $ 7.9

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- Definition Amount of contributions made that have been applied to private equity fund commitments. + References No definition available. + Details
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Namespace Prefix: | adtn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Definition Contingencies and commitments. + References No definition available. + Details
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- Definition The number of investments in private equity funds. + References No definition available. + Details
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Namespace Prefix: | adtn_
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Balance Type: | na
Period Type: | instant

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- Definition Cost of the investment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 210 -Section 50 -Paragraph 6 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=99383244&loc=d3e12121-115841 + Details
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Period Type: | instant

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- Details
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Namespace Prefix: |
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Balance Type: |
Period Type: |