Summary of Significant Accounting Policies - Summary of Impact of Restatement to Specific Line Items in Consolidated Statement of Loss and the Consolidated Statement of Comprehensive Loss (Detail) - USD ($) $ / shares in Units, shares in Thousands		3 Months Ended							6 Months Ended	9 Months Ended	12 Months Ended
	Oct. 01, 2024	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Jun. 30, 2024	Sep. 30, 2024	Dec. 31, 2024		Dec. 31, 2023		Dec. 31, 2022
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net revenue		$ 242,852,000	$ 227,704,000	$ 225,991,000	$ 226,173,000				$ 452,164,000	$ 679,868,000	$ 922,720,000		$ 1,149,100,000		$ 1,025,536,000
Total Cost of Revenue		153,296,000	144,670,000	144,732,000	155,858,000				300,590,000	445,260,000	598,556,000		817,973,000		698,284,000
Gross Profit		89,556,000	83,034,000	81,259,000	70,315,000				151,574,000	234,608,000	324,164,000		331,127,000		327,252,000
Selling, general and administrative expenses		57,013,000	57,550,000	59,364,000	58,991,000				118,355,000	175,905,000	232,918,000		258,610,000		208,889,000
Research and development expenses		49,314,000	51,577,000	60,352,000	60,215,000				120,567,000	172,144,000	221,458,000		258,311,000		173,757,000
Goodwill impairment	$ 0	0	0	0	297,353,000				297,353,000	297,353,000	297,353,000		37,874,000		0
Operating Loss		(16,771,000)	(26,093,000)	(38,457,000)	(346,244,000)				(384,701,000)	(410,794,000)	(427,565,000)		(223,668,000)		(72,827,000)
Interest and dividend income		1,631,000	664,000	366,000	397,000				763,000	1,427,000	3,058,000		2,340,000		2,123,000
Interest expense		(4,870,000)	(5,679,000)	(6,906,000)	(4,598,000)				(11,504,000)	(17,183,000)	(22,053,000)		(16,299,000)		(3,437,000)
Net investment gain		(920,000)	1,382,000	872,000	2,253,000				3,125,000	4,507,000	3,587,000		2,754,000		(11,339,000)
Other income (expense), net		687,000	(850,000)	(901,000)	1,310,000				409,000	(441,000)	246,000		1,266,000		14,517,000
Loss Before Income Taxes		(20,243,000)	(30,576,000)	(45,026,000)	(346,882,000)				(391,908,000)	(422,484,000)	(442,727,000)		(233,607,000)		(70,963,000)
Income tax (expense) benefit		(23,461,000)	(390,000)	(2,136,000)	18,647,000				16,511,000	16,121,000	(7,340,000)		(28,299,000)		62,075,000
Net Loss		(43,704,000)	(30,966,000)	(47,162,000)	(328,235,000)	$ (800,000)	$ (100,000)	$ (0)	(375,397,000)	(406,363,000)	(450,067,000)		(261,906,000)		(8,888,000)
Less: Net Income (Loss) attributable to non-controlling interest		2,407,000	2,382,000	2,505,000	2,530,000				5,035,000	7,417,000	9,824,000	[1],[2]	6,946,000	[1],[3]	(6,851,000)	[1]
Net Loss attributable to ADTRAN Holdings, Inc.		$ (46,111,000)	$ (33,348,000)	$ (49,667,000)	$ (330,765,000)				$ (380,432,000)	$ (413,780,000)	$ (459,891,000)		$ (268,852,000)		$ (2,037,000)
Weighted average shares outstanding – basic		79,091	78,952	78,852	78,814				78,803	78,873	78,928		78,416		62,346
Weighted average shares outstanding – diluted		79,091	78,952	78,852	78,814				78,803	78,873	78,928		78,416		62,346
Loss per common share attributable to ADTRAN Holdings, Inc. - basic		$ (0.58)	$ (0.38)	$ (0.63)	$ (4.2)				$ (4.83)	$ (5.21)	$ (5.79)	[4]	$ (3.43)		$ (0.03)
Loss per common share attributable to ADTRAN Holdings, Inc. - diluted		$ (0.58)	$ (0.38)	$ (0.63)	$ (4.2)				$ (4.83)	$ (5.21)	$ (5.79)	[4]	$ (3.43)		$ (0.03)
Other Comprehensive Loss, net of tax
Net unrealized gain (loss) on available-for-sale securities					$ 0								$ 454,000		$ (284,000)
Defined benefit plan adjustments		$ 1,437,000	$ 109,000	$ (7,000)	(60,000)				$ (67,000)	$ 42,000	$ 1,479,000		(1,490,000)		4,597,000
Foreign currency translation loss		(37,344,000)	18,802,000	(1,442,000)	(17,773,000)				(19,215,000)	(411,000)	(37,755,000)		22,822,000		53,396,000
Other Comprehensive (Loss) Income, net of tax		(35,907,000)	18,911,000	(1,449,000)	(17,833,000)				(19,282,000)	(369,000)	(36,276,000)		21,786,000		57,709,000
Comprehensive Loss, net of tax		(79,611,000)	(12,055,000)	(48,611,000)	(346,068,000)				(394,679,000)	(406,732,000)	(486,343,000)		(240,120,000)		48,821,000
Less: Comprehensive Income attributable to non-controlling interest		2,407,000	2,382,000	2,504,000	2,531,000				5,035,000	7,417,000	9,824,000		7,328,000		12,818,000
Comprehensive Loss attributable to ADTRAN Holdings, Inc., net of tax		(82,018,000)	(14,437,000)	(51,115,000)	(348,599,000)				(399,714,000)	(414,149,000)	(496,167,000)		(247,448,000)		36,003,000
Network Solutions [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net revenue		197,009,000	181,488,000	179,194,000	181,273,000				360,467,000	541,955,000	738,964,000		974,389,000		916,793,000
Total Cost of Revenue		135,861,000	128,320,000	124,773,000	128,266,000				253,039,000	381,359,000	517,220,000		724,518,000		647,105,000
Gross Profit											213,147,000		225,558,000		269,688,000
Goodwill impairment					297,400,000
Services & Support [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net revenue		45,843,000	46,216,000	46,797,000	44,900,000				91,697,000	137,913,000	183,756,000		174,711,000		108,743,000
Total Cost of Revenue		17,435,000	16,678,000	19,816,000	18,810,000				38,626,000	55,304,000	72,739,000		69,142,000		51,179,000
Gross Profit											111,017,000		105,569,000		57,564,000
Goodwill impairment					0								37,900,000
Network Solutions - Inventory Write-down and Other Charges [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Total Cost of Revenue											8,597,000
Network Solutions - Inventory Write Down [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Total Cost of Revenue		0	(328,000)	143,000					8,925,000	8,597,000			24,313,000
Network Solutions - Inventory Write-Down and Other Changes [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Total Cost of Revenue					8,782,000						8,597,000		24,313,000		$ 0
As Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net revenue		242,852,000	227,704,000	225,991,000	226,173,000				452,164,000	679,868,000	922,720,000		1,149,100,000
Total Cost of Revenue		151,619,000	142,453,000	144,416,000	153,918,000				298,334,000	440,787,000	592,406,000		816,037,000
Gross Profit		91,233,000	85,251,000	81,575,000	72,255,000				153,830,000	239,081,000	330,314,000		333,063,000
Selling, general and administrative expenses		57,155,000	57,621,000	59,493,000	59,100,000				118,593,000	176,214,000	233,369,000		258,149,000
Research and development expenses		49,210,000	51,614,000	60,388,000	60,251,000				120,639,000	172,253,000	221,463,000		258,311,000
Goodwill impairment		0	0	0	292,583,000				292,583,000	292,583,000	292,583,000		37,874,000
Operating Loss		(15,132,000)	(23,984,000)	(38,306,000)	(339,679,000)				(377,985,000)	(401,969,000)	(417,101,000)		(221,271,000)
Interest and dividend income		1,631,000	664,000	366,000	397,000				763,000	1,427,000	3,058,000		2,340,000
Interest expense		(4,870,000)	(5,679,000)	(6,906,000)	(4,598,000)				(11,504,000)	(17,183,000)	(22,053,000)		(16,299,000)
Net investment gain		(920,000)	1,382,000	872,000	2,253,000				3,125,000	4,507,000	3,587,000		2,754,000
Other income (expense), net		687,000	(850,000)	(901,000)	1,310,000				409,000	(441,000)	246,000		1,266,000
Loss Before Income Taxes		(18,604,000)	(28,467,000)	(44,875,000)	(340,317,000)				(385,192,000)	(413,659,000)	(432,263,000)		(231,210,000)
Income tax (expense) benefit		(24,906,000)	(390,000)	(2,136,000)	18,647,000				16,511,000	16,121,000	(8,785,000)		(28,133,000)
Net Loss		(43,510,000)	(28,857,000)	(47,011,000)	(321,670,000)				(368,681,000)	(397,538,000)	(441,048,000)		(259,343,000)
Less: Net Income (Loss) attributable to non-controlling interest		2,407,000	2,382,000	2,854,000	2,880,000				5,734,000	7,417,000	9,824,000	[2]	8,345,000	[3]
Net Loss attributable to ADTRAN Holdings, Inc.		$ (45,917,000)	$ (31,239,000)	$ (49,865,000)	$ (324,550,000)				$ (374,415,000)	$ (404,955,000)	$ (450,872,000)		$ (267,688,000)
Weighted average shares outstanding – basic		79,091	78,952	78,852	78,814				78,803	78,873	78,928		78,416
Weighted average shares outstanding – diluted		79,091	78,952	78,852	78,814				78,803	78,873	78,928		78,416
Loss per common share attributable to ADTRAN Holdings, Inc. - basic		$ (0.58)	$ (0.36)	$ (0.63)	$ (4.12)				$ (4.75)	$ (5.1)	$ (5.67)		$ (3.41)
Loss per common share attributable to ADTRAN Holdings, Inc. - diluted		$ (0.58)	$ (0.36)	$ (0.63)	$ (4.12)				$ (4.75)	$ (5.1)	$ (5.67)		$ (3.41)
Other Comprehensive Loss, net of tax
Net unrealized gain (loss) on available-for-sale securities					$ 0								$ 454,000
Defined benefit plan adjustments		$ 1,437,000	$ 109,000	$ (7,000)	(60,000)				$ (67,000)	$ 42,000	$ 1,479,000		(1,490,000)
Foreign currency translation loss		(37,917,000)	18,988,000	(1,375,000)	(17,745,000)				(19,120,000)	(130,000)	(38,047,000)		22,753,000
Other Comprehensive (Loss) Income, net of tax		(36,480,000)	19,097,000	(1,382,000)	(17,805,000)				(19,187,000)	(88,000)	(36,568,000)		21,717,000
Comprehensive Loss, net of tax		(79,990,000)	(9,760,000)	(48,393,000)	(339,475,000)				(387,868,000)	(397,626,000)	(477,616,000)		(237,626,000)
Less: Comprehensive Income attributable to non-controlling interest		2,407,000	2,382,000	2,854,000	2,880,000				5,734,000	7,417,000	9,824,000		8,727,000
Comprehensive Loss attributable to ADTRAN Holdings, Inc., net of tax		(82,397,000)	(12,142,000)	(51,247,000)	(342,355,000)				(393,602,000)	(405,043,000)	(487,440,000)		(246,353,000)
As Reported [Member] | Network Solutions [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net revenue		197,009,000	181,488,000	179,194,000	181,273,000				360,467,000	541,955,000	738,964,000		974,389,000
Total Cost of Revenue		134,184,000	126,103,000	124,457,000	126,326,000				250,783,000	376,886,000	511,070,000		722,582,000
As Reported [Member] | Services & Support [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net revenue		45,843,000	46,216,000	46,797,000	44,900,000				91,697,000	137,913,000	183,756,000		174,711,000
Total Cost of Revenue		17,435,000	16,678,000	19,816,000	18,810,000				38,626,000	55,304,000	72,739,000		69,142,000
As Reported [Member] | Network Solutions - Inventory Write-down and Other Charges [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Total Cost of Revenue											8,597,000
As Reported [Member] | Network Solutions - Inventory Write Down [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Total Cost of Revenue		0	(328,000)	143,000					8,925,000	8,597,000			24,313,000
As Reported [Member] | Network Solutions - Inventory Write-Down and Other Changes [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Total Cost of Revenue					8,782,000
Adjustment [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net revenue		0	0	0	0				0	0
Total Cost of Revenue		1,677,000	2,217,000	316,000	1,940,000				2,256,000	4,473,000	6,150,000		1,936,000
Gross Profit		(1,677,000)	(2,217,000)	(316,000)	(1,940,000)				(2,256,000)	(4,473,000)	(6,150,000)		(1,936,000)
Selling, general and administrative expenses		(142,000)	(71,000)	(129,000)	(109,000)				(238,000)	(309,000)	(451,000)		461,000
Research and development expenses		104,000	(37,000)	(36,000)	(36,000)				(72,000)	(109,000)	(5,000)
Goodwill impairment		0	0	0	4,770,000				4,770,000	4,770,000	4,770,000
Operating Loss		(1,639,000)	(2,109,000)	(151,000)	(6,565,000)				(6,716,000)	(8,825,000)	(10,464,000)		(2,397,000)
Interest and dividend income		0	0	0	0				0	0
Interest expense		0	0	0	0				0	0
Net investment gain		0	0	0	0				0	0
Other income (expense), net		0	0	0	0				0	0
Loss Before Income Taxes		(1,639,000)	(2,109,000)	(151,000)	(6,565,000)				(6,716,000)	(8,825,000)	(10,464,000)		(2,397,000)
Income tax (expense) benefit		1,445,000			0						1,445,000		(166,000)
Net Loss		(194,000)	(2,109,000)	(151,000)	(6,565,000)				(6,716,000)	(8,825,000)	(9,019,000)		(2,563,000)
Less: Net Income (Loss) attributable to non-controlling interest		0	0	(349,000)	(350,000)				(699,000)				(1,399,000)	[3]
Net Loss attributable to ADTRAN Holdings, Inc.		$ (194,000)	$ (2,109,000)	$ 198,000	$ (6,215,000)				$ (6,017,000)	$ (8,825,000)	$ (9,019,000)		$ (1,164,000)
Weighted average shares outstanding – basic		79,091	78,952	78,852	78,814				78,803	78,873	78,928		78,416
Weighted average shares outstanding – diluted		79,091	78,952	78,852	78,814				78,803	78,873	78,928		78,416
Loss per common share attributable to ADTRAN Holdings, Inc. - basic		$ (0)	$ (0.02)	$ 0	$ (0.08)				$ (0.08)	$ (0.11)	$ (0.12)		$ (0.01)
Loss per common share attributable to ADTRAN Holdings, Inc. - diluted		$ (0)	$ (0.02)	$ 0	$ (0.08)				$ (0.08)	$ (0.11)	$ (0.12)		$ (0.01)
Other Comprehensive Loss, net of tax
Net unrealized gain (loss) on available-for-sale securities					$ 0
Defined benefit plan adjustments		$ 0			0
Foreign currency translation loss		573,000	$ (186,000)	$ (67,000)	(28,000)				$ (95,000)	$ (281,000)	$ 292,000		$ 69,000
Other Comprehensive (Loss) Income, net of tax		573,000	(186,000)	(67,000)	(28,000)				(95,000)	(281,000)	292,000		69,000
Comprehensive Loss, net of tax		379,000	(2,295,000)	(218,000)	(6,593,000)				(6,811,000)	(9,106,000)	(8,727,000)		(2,494,000)
Less: Comprehensive Income attributable to non-controlling interest		0	0	(350,000)	(349,000)				(699,000)				(1,399,000)
Comprehensive Loss attributable to ADTRAN Holdings, Inc., net of tax		379,000	(2,295,000)	132,000	(6,244,000)				(6,112,000)	(9,106,000)	(8,727,000)		(1,095,000)
Adjustment [Member] | Network Solutions [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net revenue		0	0	0	0				0	0
Total Cost of Revenue		1,677,000	2,217,000	316,000	1,940,000				2,256,000	4,473,000	$ 6,150,000		$ 1,936,000
Adjustment [Member] | Services & Support [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net revenue		0	0	0	0				0	0
Total Cost of Revenue		0	0	0	0				0	0
Adjustment [Member] | Network Solutions - Inventory Write Down [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Total Cost of Revenue		$ 0	$ 0	$ 0					$ 0	$ 0
Adjustment [Member] | Network Solutions - Inventory Write-Down and Other Changes [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Total Cost of Revenue					$ 0

[1] For the year ended December 31, 2024 we accrued $9.8 million of net income attributable to non-controlling interest, representing the recurring cash compensation earned by non-controlling interest shareholders post-DPLTA. For the year ended December 31, 2023, we accrued $10.1 million, representing the recurring cash compensation earned by non-controlling interest shareholders post-DPLTA, partially offset by a $3.2 million net loss attributable to non-controlling interests pre-DPLTA.12-24

[2] For the year ended December 31, 2024 we accrued $9.8 million of net income attributable to non-controlling interest, representing the recurring cash compensation earned by non-controlling interest shareholders post-DPLTA

[3] For the year ended December 31, 2023, we have recognized $10.1 million, representing the recurring cash compensation earned by non-controlling interest shareholders post-DPLTA partially offset by a $3.2 million net loss attributable to non-controlling interests pre-DPLTA for the year ended December 31, 2023.

[4] Loss per common share attributable to ADTRAN Holdings, Inc. - basic and diluted - reflects a $3.0 million effect of redemption of RNCI for the year ended December 31, 2024. See Note 19 for additional information.