v3.26.1
Document and Entity Information - shares
 6 Months Ended
Jun. 30, 2026
Jul. 27, 2026
Cover [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Jun. 30, 2026  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q2  
Trading Symbol ACHC  
Entity Registrant Name Acadia Healthcare Company, Inc.  
Entity Central Index Key 0001520697  
Current Fiscal Year End Date --12-31  
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  
Title of 12(b) Security Common Stock, $.01 par value  
Security Exchange Name NASDAQ  
Entity File Number 001-35331  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 45-2492228  
Entity Address, Address Line One 4020 Aspen Grove Drive  
Entity Address, Address Line Two Suite 900  
Entity Address, City or Town Franklin  
Entity Address, State or Province TN  
Entity Address, Postal Zip Code 37067  
City Area Code 615  
Local Phone Number 861-6000  
Document Quarterly Report true  
Document Transition Report false  
Entity Common Stock, Shares Outstanding   93,100,275