XML 66 R52.htm IDEA: XBRL DOCUMENT
v3.21.1

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands | 3 Months Ended |
--- | --- | ---
Mar. 31, 2021 | Mar. 31, 2020 | Dec. 31, 2020
Income Tax Disclosure [Line Items] |  |  |
Effective tax rate expense (benefit) | 53.90% | 30.50% |
Income tax benefit, result of CARES act of 2020 |  | $ (7,400) |
Income tax expense, result of Alabama business tax competitiveness act | $ 1,600 |  |
Deferred tax assets, gross | 57,952 |  | $ 55,687
Valuation allowance established against deferred tax assets | 48,504 |  | 45,818
Deferred tax assets | 9,448 |  | 9,869
Domestic [Member] |  |  |
Income Tax Disclosure [Line Items] |  |  |
Valuation allowance established against deferred tax assets | 2,700 |  |
Deferred tax assets, gross | 46,479 |  | 43,791
Valuation allowance established against deferred tax assets | $ 46,479 |  | $ 43,791

X
- Definition Income Tax Disclosure [Line Items] + References No definition available. + Details
Name: | adtn_IncomeTaxDisclosureLineItems
Namespace Prefix: | adtn_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Income tax expense (benefit) result of Alabama business tax competitiveness act. + References No definition available. + Details
Name: | adtn_IncomeTaxExpenseBenefitResultOfAlabamaBusinessTaxCompetitivenessAct
Namespace Prefix: | adtn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Income tax expense benefit, result of CARES act of 2020. + References No definition available. + Details
Name: | adtn_IncomeTaxExpenseBenefitResultOfCARESActOf2020
Namespace Prefix: | adtn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Valuation allowance established against deferred tax assets. + References No definition available. + Details
Name: | adtn_ValuationAllowanceEstablishedAgainstDeferredTaxAssets
Namespace Prefix: | adtn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319 + Details
Name: | us-gaap_DeferredTaxAssetsGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319 + Details
Name: | us-gaap_DeferredTaxAssetsNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319 + Details
Name: | us-gaap_DeferredTaxAssetsValuationAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319 + Details
Name: | us-gaap_EffectiveIncomeTaxRateContinuingOperations
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_IncomeTaxAuthorityAxis=us-gaap_DomesticCountryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |