v3.10.0.1
Document and Entity Information - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Feb. 25, 2019
Jun. 30, 2018
Document and Entity Information [Abstract]      
Entity Registrant Name ST JOE CO    
Trading Symbol JOE    
Entity Central Index Key 0000745308    
Current Fiscal Year End Date --12-31    
Document Type 10-K    
Document Period End Date Dec. 31, 2018    
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus FY    
Amendment Flag false    
Entity Current Reporting Status Yes    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Filer Category Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
Entity Shell Company false    
Entity Public Float     $ 351.9
Entity Common Stock, Shares Outstanding   60,200,534