XML 14 R1.htm IDEA: XBRL DOCUMENT v3.21.1
Cover Page - shares
 3 Months Ended
Mar. 31, 2021
May 10, 2021
Document Information [Line Items]    
Document Type 10-Q  
Amendment Flag false  
Document Quarterly Report true  
Document Transition Report false  
Document Period End Date Mar. 31, 2021  
Document Fiscal Year Focus 2021  
Document Fiscal Period Focus Q1  
Entity Registrant Name Compass, Inc.  
Entity Central Index Key 0001563190  
Current Fiscal Year End Date --12-31  
Entity File Number 001-40291  
Entity Tax Identification Number 30-0751604  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Filer Category Non-accelerated Filer  
Entity Shell Company false  
Trading Symbol COMP  
Security Exchange Name NYSE  
Title of 12(g) Security Class A Common Stock, $0.00001 par value per share  
Entity Current Reporting Status No  
Entity Interactive Data Current Yes  
Entity Incorporation, State or Country Code DE  
Entity Address, Address Line One 90 Fifth Avenue, 3rd Floor  
Entity Address, State or Province NY  
Entity Address, Postal Zip Code 10011  
City Area Code 212  
Local Phone Number 913-9058  
Entity Common Stock, Shares Outstanding   393,973,089