v3.25.2
COVER - shares
 6 Months Ended
Jun. 30, 2025
Jul. 15, 2025
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2025  
Document Transition Report false  
Entity File Number 000-23211  
Entity Registrant Name CASELLA WASTE SYSTEMS, INC.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 03-0338873  
Entity Address, Address Line One 25 Greens Hill Lane,  
Entity Address, City or Town Rutland,  
Entity Address, State or Province VT  
Entity Address, Postal Zip Code 05701  
City Area Code 802  
Local Phone Number 775-0325  
Title of 12(b) Security Class A common stock, $0.01 par value per share  
Trading Symbol CWST  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Central Index Key 0000911177  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q2  
Amendment Flag false  
Class A Common Stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   62,502,263
Class B Common Stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   988,200