Document and Entity Information - shares
3 Months Ended
Mar. 31, 2018
Apr. 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  
Entity Filer Category Accelerated Filer  
Document Type 10-Q  
Document Period End Date Mar. 31, 2018  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q1  
Amendment Flag false  
Entity Current Reporting Status Yes  
Entity Common Stock, Shares Outstanding (in shares)   64,636,771