Condensed Consolidated Statements of Comprehensive (Loss) Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Statement of Comprehensive Income [Abstract]
Net Loss	$ (8,704)	$ (18,258)	$ (7,774)	$ (27,206)
Other Comprehensive (Loss) Income, net of tax
Defined benefit plan adjustments	(49)	268	(115)	399
Foreign currency translation (loss) gain	(5,803)	46,455	(14,568)	66,702
Other Comprehensive (Loss) Income, net of tax	(5,852)	46,723	(14,683)	67,101
Comprehensive (Loss) Income, net of tax	(14,556)	28,465	(22,457)	39,895
Less: Comprehensive Income attributable to non-controlling interest	2,201	2,273	4,452	4,592
Comprehensive (Loss) Income attributable to ADTRAN Holdings, Inc., net of tax	$ (16,757)	$ 26,192	$ (26,909)	$ 35,303

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income (loss) and other comprehensive income (loss), attributable to noncontrolling interests. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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