Commitments and Contingencies - Additional Information (Detail) € in Thousands, shares in Thousands, $ in Thousands	1 Months Ended		3 Months Ended
	Apr. 30, 2026 USD ($)	Apr. 30, 2026 EUR (€)	Mar. 31, 2026 USD ($) shares	Mar. 31, 2026 EUR (€) shares	Mar. 31, 2025 USD ($) shares	Mar. 31, 2025 EUR (€) shares	Mar. 31, 2026 EUR (€)	Dec. 31, 2025 USD ($)
Commitments And Contingencies Line Items
Percentage of guaranteed interest rate			5.00%				5.00%
Percentage of guaranteed interest rate plus a variable component			1.27%				1.27%
Aggregate exit compensation payments obligation including guaranteed interest			$ 351,700				€ 304,400
Expire date of exit compensation			Mar. 16, 2023	Mar. 16, 2023
Annual recurring compensation obligation			$ 9,000	€ 7,800	$ 9,000	€ 7,800
Accrued annual recurring compensation obligation			2,200		2,400
Commitments related to performance bonds			$ 22,200					$ 22,400
Commitments related to performance bonds expiration month and year			2029-04	2029-04
Purchase obligations			$ 223,700
Number of shares tendered | shares			200	200
Liability			$ 678,525					685,335
Employeess deferrals			$ 23,449					32,203
401(k) Retirement Plan
Commitments And Contingencies Line Items
Employeess deferrals								$ 1,400
Adtran Networks [Member]
Commitments And Contingencies Line Items
Exit compensation payments					$ 13	€ 12
Number of shares tendered | shares			200	200
Adtran Networks [Member] | Maximum [Member]
Commitments And Contingencies Line Items
Number of shares tendered | shares			1	1	1	1
Adtran Networks [Member] | Subsequent Events [Member]
Commitments And Contingencies Line Items
Exit compensation payments	$ 4,100	€ 3,600