XML 48 R38.htm IDEA: XBRL DOCUMENT
v3.23.2

Segment and Non-Tariffed Business Reporting - Narrative (Details) | 6 Months Ended
--- | ---
Jun. 30, 2023 subsidiary
Segment Reporting [Abstract] |
Number of subsidiaries | 5

X
- Definition Number of Subsidiaries + References No definition available. + Details
Name: | sjw_NumberOfSubsidiaries
Namespace Prefix: | sjw_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

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