v3.26.1

Cover Page - shares	3 Months Ended
Cover Page - shares	Mar. 31, 2026	May 07, 2026
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2026
Document Transition Report	false
Entity File Number	001-39687
Entity Registrant Name	GPGI, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	85-2749902
Entity Address, Address Line One	309 Pierce Street
Entity Address, City or Town	Somerset
Entity Address, State or Province	NJ
Entity Address, Postal Zip Code	08873
City Area Code	908
Local Phone Number	518-0500
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		289,861,445
Entity Central Index Key	0001823144
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2026
Document Fiscal Period Focus	Q1
Amendment Flag	false
New York Stock Exchange
Document Information [Line Items]
Title of 12(b) Security	Class A Common Stock, $0.0001 par value per share
Trading Symbol	GPGI
Security Exchange Name	NYSE

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GPGI, Inc. 10-Q