Regulatory Matters (Details 9) (GSWC, USD $)			1 Months Ended	12 Months Ended	1 Months Ended				3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Aug. 31, 2012 BVES General Rate Case	Dec. 31, 2012 BVES General Rate Case	Dec. 31, 2012 Renewables Portfolio Standard	May 31, 2012 Renewables Portfolio Standard	Aug. 31, 2011 Renewables Portfolio Standard	Jun. 30, 2011 Renewables Portfolio Standard	Sep. 30, 2012 Renewables Portfolio Standard	Dec. 31, 2012 Renewables Portfolio Standard item	Mar. 31, 2012 Renewables Portfolio Standard
Regulatory matters:
Amount of retroactive ratemaking proposal included in DRA's recommendation to increase accumulated depreciation			$ 2,000,000
Portion of deferred rate case cost borne by shareholders				50.00%
Net regulatory assets	176,015,000	179,957,000		2,300,000
Portion of deferred rate case costs required to be written off, if DRA prevails				50.00%
Agreement period to purchase renewable energy credits					10 years
Number of renewable energy credits that would be purchased										582,000
Application filed with the CPUC for recovery of legal and outside service costs incurred								1,200,000
Regulatory asset											1,300,000
Recovery period						12 months
Term of contract with LACSD to purchase renewable energy created from landfill gas					10 years
Period of right to terminate notice waived under the settlement							14 months
Purchase cost of REC's									$ 325,000