Supplemental Cash Flow Information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Taxes and Interest Paid:
Income taxes paid	$ 10,880	$ 19,411	$ 31,842
Interest paid	22,144	22,495	22,671
Non-Cash Transactions:
Accrued payables for investment in utility plant	19,515	12,113	13,717
Property installed by developers and conveyed	2,819	2,069	1,264
GSWC
Taxes and Interest Paid:
Income taxes paid	7,083	11,027	25,810
Interest paid	22,144	22,495	22,463
Non-Cash Transactions:
Accrued payables for investment in utility plant	19,515	12,113	13,717
Property installed by developers and conveyed	$ 2,819	$ 2,069	$ 1,264