Employee Benefit Plans (Pension Benefit Plan) - Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Net actuarial (gain) loss	$ 5,245	$ 7,943

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