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Summary of Significant Accounting Policies - Additional Information (Detail) € / shares in Units, $ / shares in Units, $ in Thousands, € in Millions |  | 3 Months Ended | 9 Months Ended |  |  |
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Sep. 19, 2025 USD ($) | Sep. 30, 2025 USD ($) $ / shares shares | Sep. 30, 2025 EUR (€) shares | Sep. 30, 2024 USD ($) $ / shares shares | Sep. 30, 2024 EUR (€) shares | Sep. 30, 2025 USD ($) $ / shares shares | Sep. 30, 2025 EUR (€) € / shares shares | Sep. 30, 2024 USD ($) $ / shares shares | Sep. 30, 2024 EUR (€) shares | Sep. 30, 2025 EUR (€) | Dec. 31, 2024 USD ($) | Oct. 18, 2022 shares
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Cash compensation per share | € / shares |  |  |  |  |  |  | € 17.21 |  |  |  |  |
Recurring cash compensation per share | € / shares |  |  |  |  |  |  | € 0.52 |  |  |  |  |
Percentage of guaranteed interest rate |  | 5.00% |  |  |  | 5.00% |  |  |  | 5.00% |  |
Percentage of guaranteed interest rate plus a variable component |  | 1.27% |  |  |  | 1.27% |  |  |  | 1.27% |  |
Aggregate exit compensation payments obligation including guaranteed interest |  | $ 378,700 |  |  |  | $ 378,700 |  |  |  | € 322.7 |  |
Expire date of exit compensation |  |  |  |  |  | Mar. 16, 2023 | Mar. 16, 2023 |  |  |  |  |
Annual recurring compensation obligation |  |  |  |  |  | $ 10,000 | € 8.5 |  |  |  |  |
Accrued annual recurring compensation obligation |  | 2,500 |  | $ 2,400 |  | 7,500 |  | $ 7,400 |  |  |  |
Cash and cash equivalents |  | 93,682 |  | $ 88,456 |  | $ 93,682 |  | $ 88,456 |  |  | $ 76,021 |
3.75% Convertible Senior Notes Due 2030 [Member] |  |  |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Aggregate principal amount | $ 201,300 |  |  |  |  |  |  |  |  |  |  |
Debt instrument, interest rate, stated percentage | 3.75% |  |  |  |  |  |  |  |  |  |  |
Net proceeds | $ 192,800 |  |  |  |  |  |  |  |  |  |  |
Debt instrument, maturity date | Sep. 15, 2030 |  |  |  |  |  |  |  |  |  |  |
Wells Fargo Credit Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Net leverage ratio |  |  |  |  |  | 0.0325 | 0.0325 |  |  |  |  |
Wells Fargo Credit Agreement [Member] | Acorn HoldCo, Inc., [Member] |  |  |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Available for future borrowings |  | 319,200 |  |  |  | $ 319,200 |  |  |  |  |  |
Credit agreement current borrowing capacity |  | 232,000 |  |  |  | 232,000 |  |  |  |  |  |
Wells Fargo Credit Agreement Amendment [Member] | Credit Parties [Member] |  |  |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Cash and cash equivalents |  | 50,000 |  |  |  | 50,000 |  |  |  |  |  |
Wells Fargo Credit Agreement Amendment [Member] | Company and Subsidiaries [Member] |  |  |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Cash and cash equivalents |  | $ 70,000 |  |  |  | $ 70,000 |  |  |  |  |  |
Maximum [Member] | Wells Fargo Credit Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Net leverage ratio |  |  |  |  |  | 0.05 | 0.05 |  |  |  |  |
Maximum [Member] | Wells Fargo Credit Agreement [Member] | First Quarter Ending Springing Covenant Period [Member] |  |  |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Net leverage ratio |  |  |  |  |  | 0.04 | 0.04 |  |  |  |  |
Minimum [Member] | Wells Fargo Credit Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Fixed charge coverage ratio |  |  |  |  |  | 0.0125 | 0.0125 |  |  |  |  |
Minimum [Member] | Wells Fargo Credit Agreement [Member] | Third And Fourth Quarters Ending Springing Covenant Event [Member] |  |  |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Net leverage ratio |  |  |  |  |  | 0.035 | 0.035 |  |  |  |  |
Adtran Networks [Member] |  |  |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Annual recurring compensation payment per share | $ / shares |  | $ 0.52 |  |  |  | $ 0.52 |  |  |  |  |  |
Accrued liability per share | $ / shares |  |  |  | $ 0.59 |  |  |  | $ 0.59 |  |  |  |
Number of shares tendered | shares |  | 900,000 | 900,000 | 800,000 | 800,000 | 900,000 | 900,000 | 800,000 | 800,000 |  |  |
Exit compensation payments |  | $ 19,900 | € 16.9 | $ 17,400 | € 15.7 | $ 19,900 | € 16.9 | $ 17,400 | € 15.7 |  |  |
Adtran Networks [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of additional shares authorized to purchase | shares |  |  |  |  |  |  |  |  |  |  |  | 15,346,544
Number of shares tendered | shares |  | 1,000 | 1,000 |  |  | 1,000 | 1,000 |  |  |  |  |

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