Condensed Consolidated Statements of Comprehensive (Loss) Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ 930	$ (8,948)
Other Comprehensive (Loss) Income, net of tax
Defined benefit plan adjustments	(66)	131
Foreign currency translation (loss) gain	(8,765)	20,247
Other Comprehensive (Loss) Income, net of tax	(8,831)	20,378
Comprehensive (Loss) Income, net of tax	(7,901)	11,430
Less: Comprehensive Income attributable to non-controlling interest	2,251	2,319
Comprehensive (Loss) Income attributable to ADTRAN Holdings, Inc., net of tax	$ (10,152)	$ 9,111