v3.26.1
Cover - shares
 6 Months Ended
Jun. 30, 2026
Aug. 06, 2026
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Transition Report false  
Entity Interactive Data Current Yes  
Amendment Flag false  
Document Period End Date Jun. 30, 2026  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q2  
Entity Registrant Name OYSTER ENTERPRISES II ACQUISITION CORP  
Entity Central Index Key 0002042182  
Entity File Number 001-42662  
Entity Tax Identification Number 61-2218657  
Entity Incorporation, State or Country Code E9  
Current Fiscal Year End Date --12-31  
Entity Current Reporting Status Yes  
Entity Shell Company true  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Address, Address Line One 801 Brickell Avenue  
Entity Address, Address Line Two 8th Floor  
Entity Address, City or Town Miami  
Entity Address, State or Province FL  
Entity Address, Postal Zip Code 33131  
City Area Code (786)  
Local Phone Number 744-7720  
Units, each consisting of one Class A Ordinary Share and one Right    
Document Information [Line Items]    
Title of 12(b) Security Units, each consisting of one Class A Ordinary Share and one Right  
Trading Symbol OYSEU  
Security Exchange Name NASDAQ  
Class A Ordinary Shares, par value $0.0001 per share    
Document Information [Line Items]    
Title of 12(b) Security Class A Ordinary Shares, par value $0.0001 per share  
Trading Symbol OYSE  
Security Exchange Name NASDAQ  
Rights, each Right entitling the holder to receive one-tenth (1/10) of one Class A Ordinary Share upon the consummation of an initial business combination    
Document Information [Line Items]    
Title of 12(b) Security Rights, each Right entitling the holder to receive one-tenth (1/10) of one Class A Ordinary Share  
Trading Symbol OYSER  
Security Exchange Name NASDAQ  
Class A Ordinary Shares    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   26,008,000
Class B Ordinary Shares    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   7,906,250