Quarterly report pursuant to Section 13 or 15(d)

Cover Page

Cover Page - shares
3 Months Ended
Mar. 31, 2021
Jun. 01, 2021
Document Information [Line Items]    
Document Type 10-Q  
Entity Registrant Name Altimar Acquisition Corp. II  
Document Period End Date Mar. 31, 2021  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Shell Company true  
Entity Central Index Key 0001836176  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2021  
Document Fiscal Period Focus Q1  
Amendment Flag false  
Entity Address, State or Province NY  
Entity Incorporation, State or Country Code E9  
Entity Address, Address Line One 40 West 57th Street  
Entity Address, Address Line Two 33rd Floor  
Entity Address, City or Town New York  
Entity Address, Postal Zip Code 10019  
City Area Code 212  
Local Phone Number 287-6767  
Entity File Number 001-39994  
Entity Tax Identification Number 98-1571400  
Document Quarterly Report true  
Document Transition Report false  
Class A ordinary shares    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   34,500,000
Trading Symbol ATMR  
Title of 12(b) Security Class A ordinary shares, $0.0001 par value  
Security Exchange Name NYSE  
Class B ordinary shares    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   8,625,000
Units Each Consisting Of One Share Of Class Common Stock And One Fourth Of One Redeemable Warrant    
Document Information [Line Items]    
Trading Symbol ATMR.U  
Title of 12(b) Security Units, each consisting of oneClass A ordinary share, $0.0001 par value, and one-fourth of one redeemable warrant  
Security Exchange Name NYSE  
Redeemable warrants, each whole warrant exercisable    
Document Information [Line Items]    
Trading Symbol ATMR WS  
Title of 12(b) Security Warrants, each whole warrant exercisable for one Class A ordinary share, each at an exercise price of $11.50 per share  
Security Exchange Name NYSE