XML 17 R1.htm IDEA: XBRL DOCUMENT v3.25.4
Document and Entity Information - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Feb. 13, 2026
Jun. 30, 2025
Cover [Abstract]      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2025    
Document Transition Report false    
Securities Act File Number 1-13011    
Entity Registrant Name Comfort Systems USA, Inc.    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 76-0526487    
Entity Address, Address Line One 9753 Katy Freeway    
Entity Address, Address Line Two Suite 700    
Entity Address, City or Town Houston    
Entity Address, State or Province TX    
Entity Address, Postal Zip Code 77024    
City Area Code 713    
Local Phone Number 830-9600    
Title of 12(b) Security Common Stock, $.01 par value    
Trading Symbol FIX    
Security Exchange Name NYSE    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
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 Public Float     $ 18,640
Entity Common Stock, Shares Outstanding   35,174,967  
Documents Incorporated by Reference

The information required by Part III (other than the required information regarding executive officers) is incorporated by reference from the registrant’s definitive proxy statement, which will be filed with the Commission not later than 120 days following December 31, 2025.

    
Entity Central Index Key 0001035983    
Document Fiscal Year Focus 2025    
Document Fiscal Period Focus FY    
Current Fiscal Year End Date --12-31    
Amendment Flag false    
ICFR Auditor Attestation Flag true    
Document Financial Statement Error Correction [Flag] false    
Auditor Name Deloitte & Touche LLP    
Auditor Firm ID 34    
Auditor Location Houston, Texas