XML 17 R1.htm IDEA: XBRL DOCUMENT v3.22.0.1
Document and Entity Information - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2021
Feb. 17, 2022
Jun. 30, 2021
Entity [Abstract]      
Document Type 10-K    
Document Annual Report true    
Current Fiscal Year End Date --12-31    
Document Period End Date Dec. 31, 2021    
Document Transition Report false    
Entity File Number 001-8966    
Entity Registrant Name SJW GROUP    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 77-0066628    
Entity Address, Address Line One 110 West Taylor Street,    
Entity Address, City or Town San Jose,    
Entity Address, State or Province CA    
Entity Address, Postal Zip Code 95110    
City Area Code (408)    
Local Phone Number 279-7800    
Title of 12(b) Security Common Stock, par value $0.001 per share    
Trading Symbol SJW    
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    
ICFR Auditor Attestation Flag true    
Entity Shell Company false    
Entity Public Float     $ 1,737
Entity Common Stock, Shares Outstanding   30,228,919  
Documents Incorporated by Reference Portions of the registrant’s Proxy Statement relating to the registrant’s Annual Meeting of Stockholders are incorporated by reference into Part III of this Form 10-K where indicated.    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2021    
Amendment Flag false    
Entity Central Index Key 0000766829