XML 11 R1.htm IDEA: XBRL DOCUMENT v3.21.4
Document and Entity Information - shares
3 Months Ended
Dec. 31, 2021
Jan. 21, 2022
Entity Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Dec. 31, 2021  
Document Transition Report false  
Entity File Number 001-33662  
Entity Registrant Name FORESTAR GROUP INC.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 26-1336998  
Entity Address, Address Line One 2221 E. Lamar Blvd.  
Entity Address, Address Line Two Suite 790  
Entity Address, City or Town Arlington  
Entity Address, State or Province TX  
Entity Address, Postal Zip Code 76006  
City Area Code 817  
Local Phone Number 769-1860  
Title of 12(b) Security Common Stock, par value $1.00 per share  
Trading Symbol FOR  
Security Exchange Name NYSE  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   49,675,768
Entity Central Index Key 0001406587  
Current Fiscal Year End Date --09-30  
Document Fiscal Year Focus 2022  
Document Fiscal Period Focus Q1  
Amendment Flag false