Face (par) amount of debt instrument at time of issuance.

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Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Long-Term Debt - Summary of Debts Borrowed by Subsidiary (Detail) - USD ($) $ in Thousands	Jul. 01, 2019	May 04, 2016	Apr. 26, 2016	Oct. 10, 2015	Sep. 04, 2014	Apr. 11, 2013
Debt Instrument [Line Items]
Interest Rate	1.25%
IKB Deutsche Industriebank AG Borrowing Agreements \| Glatfelter Gernsbach GmbH \| IKB Deutsche Industriebank AG Member
Debt Instrument [Line Items]
Original Principal		$ 7,195	$ 10,000	$ 2,608	$ 10,000	$ 42,700
Interest Rate		1.55%	1.30%	1.55%	2.40%	2.05%