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Long-Term Debt - Summary of Debts Borrowed by Subsidiary (Detail) - IKB Deutsche Industriebank AG Borrowing Agreements [Member] - Glatfelter Gernsbach GmbH and Co KG [Member] - IKB Deutsche Industriebank AG Member - EUR (€) € in Thousands | Oct. 10, 2015 | Sep. 04, 2014 | Apr. 11, 2013
--- | --- | --- | ---
Debt Instrument [Line Items] |  |  |
Original Principal | € 2,608 | € 10,000 | € 42,700
Interest Rate | 1.55% | 2.40% | 2.05%
Maturity | Sep. 30, 2025 | Jun. 30, 2022 | Mar. 31, 2023

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