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Summary of Significant Accounting Policies - Additional Information (Detail) € in Thousands, $ in Thousands | 3 Months Ended | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | ---
Mar. 31, 2024 USD ($) shares | Mar. 31, 2024 EUR (€) shares | Mar. 31, 2023 USD ($) shares | Mar. 31, 2023 EUR (€) shares | Dec. 31, 2023 USD ($) | Mar. 31, 2024 EUR (€) | Oct. 18, 2022 shares | Jul. 18, 2022 USD ($)
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |  |  |  |
Percentage of guaranteed interest rate | 5.00% |  |  |  |  | 5.00% |  |
Percentage of guaranteed interest rate plus a variable component | 3.62% |  |  |  |  | 3.62% |  |
Aggregate exit compensation payments obligation including guaranteed interest | $ 365,700 |  |  |  |  | € 338,900 |  |
Expire date of exit compensation | Mar. 16, 2023 | Mar. 16, 2023 |  |  |  |  |  |
Annual recurring compensation obligation | $ 11,500 | € 10,600 |  |  | $ 11,500 |  |  |
Accrued annual recurring compensation obligation | $ 2,900 |  | $ 2,800 |  | 11,500 |  |  |
Number of shares tendered | shares | 1,000 | 1,000 | 62,000 | 62,000 |  |  |  |
Exit compensation payments | $ 5 | € 4 | $ 1,200 | € 1,100 |  |  |  |
Cash and cash equivalents | $ 106,757 |  |  |  | $ 87,167 |  |  |
Wells Fargo Credit Agreement [Member] |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |  |  |  |
Covenant relief period, description | the period beginning upon the purchase by the Company of at least 60% of the outstanding shares of Adtran Networks not owned by the Company as of August 9, 2023 and the three consecutive quarterly test periods after such date | the period beginning upon the purchase by the Company of at least 60% of the outstanding shares of Adtran Networks not owned by the Company as of August 9, 2023 and the three consecutive quarterly test periods after such date |  |  |  |  |  |
Wells Fargo Credit Agreement [Member] | Credit Parties [Member] |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |  |  |  |
Cash and cash equivalents |  |  |  |  |  |  |  | $ 50,000
Wells Fargo Credit Agreement [Member] | Company and Subsidiaries [Member] |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |  |  |  |
Cash and cash equivalents |  |  |  |  |  |  |  | $ 75,000
Wells Fargo Credit Agreement [Member] | Acorn HoldCo, Inc., [Member] |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |  |  |  |
Available for future borrowings | $ 203,000 |  |  |  |  |  |  |
Credit agreement current borrowing capacity | 22,700 |  |  |  |  |  |  |
Adtran Networks [Member] |  |  |  |  |  |  |  |
Summary Of Significant Accounting Policy [Line Items] |  |  |  |  |  |  |  |
Number of shares tendered | shares |  |  | 62,000 | 62,000 |  |  |  |
Exit compensation payments | $ 5 | € 4 | $ 1,200 | € 1,100 |  |  |  |
Equity ownership percentage | 34.70% |  |  |  | 34.70% | 34.70% |  |
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 |  |  |  |  |  |

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