XML 60 R46.htm IDEA: XBRL DOCUMENT
v3.21.1

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2021 | Mar. 31, 2020
Summary Of Significant Accounting Policy [Line Items] |  |
Tax benefit in other comprehensive income (loss) | $ (17) | $ 104
ASU 2016-13 [Member] |  |
Summary Of Significant Accounting Policy [Line Items] |  |
Change in Accounting Principle, Accounting Standards Update, Adopted [true false] | true |
Change in Accounting Principle, Accounting Standards Update, Adoption Date | Jan. 01, 2020 |
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false] | true |
ASU 2019-12 [Member] |  |
Summary Of Significant Accounting Policy [Line Items] |  |
Change in Accounting Principle, Accounting Standards Update, Adopted [true false] | true |
Change in Accounting Principle, Accounting Standards Update, Adoption Date | Apr. 01, 2020 |
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false] | true |
Adjustments for New Accounting Principle, Early Adoption [Member] |  |
Summary Of Significant Accounting Policy [Line Items] |  |
Tax benefit in other comprehensive income (loss) | $ (100) |
Overstatement Long-term Investment Balance at Remeasured Cost Basis [Member] |  |
Summary Of Significant Accounting Policy [Line Items] |  |
Amount of revision |  | 2,800
Errors in Net Investment Gain [Member] |  |
Summary Of Significant Accounting Policy [Line Items] |  |
Amount of revision |  | $ 1,500

X
- Definition Summary of significant accounting policy. + References No definition available. + Details
Name: | adtn_SummaryOfSignificantAccountingPolicyLineItems
Namespace Prefix: | adtn_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Indicates (true false) whether accounting standards update was adopted. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 10 -Section 65 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121329987&loc=SL120154346-209984 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 65 -Paragraph 15 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22499-107794 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 20 -Section 65 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=121483254&loc=SL120254523-199619 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 65 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121370832&loc=SL117420844-207641 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 10 -Section 65 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121646688&loc=SL121648383-210437 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 10 -Section 65 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121646688&loc=SL121648383-210437 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 926 -SubTopic 20 -Section 65 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=120154821&loc=SL120154904-197079 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 926 -SubTopic 20 -Section 65 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=120154821&loc=SL120154904-197079 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 10 -Section 65 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121646688&loc=SL120320025-210437 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 10 -Section 65 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121646688&loc=SL120320025-210437 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 65 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=120240428&loc=SL120254526-165497 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 65 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121370832&loc=SL117420844-207641 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 65 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333 Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 65 -Paragraph 15 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333 Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 10 -Section 65 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=121646688&loc=SL120254519-210437 Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 65 -Paragraph 8 -Subparagraph (a) + Details
Name: | us-gaap_ChangeInAccountingPrincipleAccountingStandardsUpdateAdopted
Namespace Prefix: | us-gaap_
Data Type: | xbrli:booleanItemType
Balance Type: | na
Period Type: | instant

X
- Definition Date accounting standards update was adopted, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 65 -Paragraph 15 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 10 -Section 65 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121329987&loc=SL120154346-209984 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 20 -Section 65 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=121483254&loc=SL120254523-199619 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 10 -Section 65 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121646688&loc=SL121648383-210437 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 10 -Section 65 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121646688&loc=SL121648383-210437 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 926 -SubTopic 20 -Section 65 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=120154821&loc=SL120154904-197079 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 10 -Section 65 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121646688&loc=SL120320025-210437 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 10 -Section 65 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121646688&loc=SL120320025-210437 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 926 -SubTopic 20 -Section 65 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=120154821&loc=SL120154904-197079 Reference 10: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22583-107794 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 65 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 65 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121370832&loc=SL117420844-207641 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 65 -Paragraph 15 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 65 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121370832&loc=SL117420844-207641 Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 10 -Section 65 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=121646688&loc=SL120254519-210437 Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 65 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=120240428&loc=SL120254526-165497 Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 65 -Paragraph 8 -Subparagraph (a) + Details
Name: | us-gaap_ChangeInAccountingPrincipleAccountingStandardsUpdateAdoptionDate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | instant

X
- Definition Indicates (true false) whether effect from applying amendment to accounting standards is immaterial. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section S99 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=112272810&loc=d3e31010-122693 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 65 -Paragraph 15 -Subparagraph (g)(2) -URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 10 -Section 65 -Paragraph 4 -Subparagraph (e)(1) -URI http://asc.fasb.org/extlink&oid=121646688&loc=SL121648383-210437 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b)(2) -URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22499-107794 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 65 -Paragraph 8 -Subparagraph (e)(3) + Details
Name: | us-gaap_ChangeInAccountingPrincipleAccountingStandardsUpdateImmaterialEffect
Namespace Prefix: | us-gaap_
Data Type: | xbrli:booleanItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of tax expense (benefit) allocated to other comprehensive income (loss). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 20 -Section 45 -Paragraph 11 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=120385591&loc=d3e39076-109324 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section 45 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=118261656&loc=d3e32136-110900 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section 45 -Paragraph 20 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=118261656&loc=d3e32211-110900 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 20 -Section 45 -Paragraph 2 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=120385591&loc=d3e38679-109324 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04(23)) -URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(21)) -URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32672-109319 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450520&loc=d3e32583-110901 Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=121641772&loc=d3e640-108580 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(19)) -URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263 + Details
Name: | us-gaap_OtherComprehensiveIncomeLossTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of each individual error being corrected in the correcting adjustment. + References No definition available. + Details
Name: | us-gaap_QuantifyingMisstatementInCurrentYearFinancialStatementsAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201613Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201912Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AdjustmentsForNewAccountingPrincipleEarlyAdoptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_QuantifyingMisstatementInCurrentYearFinancialStatementsByNatureOfErrorAxis=adtn_OverstatementOfLongTermInvestmentAtRemeasuredCostBasisMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_QuantifyingMisstatementInCurrentYearFinancialStatementsByNatureOfErrorAxis=adtn_OverstatementOfNetInvestmentGainMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |