XML 40 R30.htm IDEA: XBRL DOCUMENT
v3.22.2

Regulatory Matters - Balancing and Memorandum Accounts (Details) | Jun. 30, 2022
--- | ---
Regulated Operations [Abstract] |
Authorized revenue, threshold percentage | 2.00%

X
- Definition Threshold balance of regulatory balancing or memorandum accounts as a percentage of authorized revenue to trigger an account review. + References No definition available. + Details
Name: | sjw_RegulatoryBalancingandMemorandumAccountsReviewAuthorizedRevenueThresholdPercentage
Namespace Prefix: | sjw_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_RegulatedOperationsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration