Employee Benefit Plans (Pension Benefit Plan) - Accumulated Other Comprehensive (Loss) Income (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Retirement Benefits [Abstract]
Net actuarial loss	$ (1,824)	$ (3,231)

Defined benefit plan accumulated other comprehensive income net actuarial gains losses net of tax.

No definition available.

Name:	adtn_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetActuarialGainsLossesNetOfTax
Namespace Prefix:	adtn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant