OTHER INCOME AND EXPENSES (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Other income and expenses
Revenue	$ 16,160	$ 15,993	$ 18,190
Expense	15,822	12,312	12,452
Cal Water
Other income and expenses
Revenue	12,972	10,064	12,408
Expense	12,287	7,954	7,972
Operating and maintenance
Other income and expenses
Revenue	9,176	9,237	11,210
Expense	9,689	9,713	11,525
Meter reading and billing
Other income and expenses
Revenue	1,212	1,207	1,205
Expense	944	990	929
Leases
Other income and expenses
Revenue	1,892	2,162	2,026
Expense	330	877	805
Design and construction
Other income and expenses
Revenue	1,689	1,306	1,717
Expense	1,420	1,041	1,515
Interest income
Other income and expenses
Revenue	75	28	106
Change in value of life insurance contracts
Other income and expenses
Expense	1,876	(2,641)	(4,107)
Other non-regulated income and expenses
Other income and expenses
Revenue	2,116	2,053	1,926
Expense	$ 1,563	$ 2,332	$ 1,785