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