Regulatory Matters (Details 7) (GSWC, CPUC Subpoena, USD $)	1 Months Ended	12 Months Ended
	Dec. 31, 2011 audit	Dec. 31, 2012
Regulatory matters:
Total settlement	$ 9,500,000
Reduction in rate-base and other adjustments as per the settlement	3,000,000
Refunds provided to customers		$ 3,200,000
Number of separate independent audits of procurement practices agreed as a part of the settlement agreement	3
Period of separate independent audits of procurement practices agreed as a part of settlement agreement	10 years
Minimum
Regulatory matters:
Period of refunds to customers	12 months
Maximum
Regulatory matters:
Period of refunds to customers	36 months