Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Statement [Abstract]
OPERATING REVENUE	$ 72,402	$ 70,356	$ 134,514	$ 124,952
Production Expenses:
Purchased water	16,002	11,942	25,286	21,672
Power	1,528	2,623	2,700	4,112
Groundwater extraction charges	6,197	15,516	14,133	24,964
Other production expenses	3,065	3,001	6,062	5,863
Total production expenses	26,792	33,082	48,181	56,611
Administrative and general	11,464	9,510	22,760	18,960
Maintenance	3,844	3,573	7,212	6,847
Property taxes and other non-income taxes	2,890	2,575	5,985	5,379
Depreciation and amortization	10,202	9,495	20,361	18,980
Total operating expense	55,192	58,235	104,499	106,777
OPERATING INCOME	17,210	12,121	30,015	18,175
OTHER (EXPENSE) INCOME:
Interest on long-term debt	(5,299)	(4,553)	(10,638)	(9,095)
Mortgage and other interest expense	(319)	(401)	(632)	(729)
Gain on sale of California Water Service Group stock	0	2,017	0	2,017
Gain on sale of real estate investment	0	273	0	273
Dividend income	44	42	87	105
Other, net	230	439	523	659
Income before income taxes	11,866	9,938	19,355	11,405
Provision for income taxes	4,405	3,092	7,199	3,653
NET INCOME	7,461	6,846	12,156	7,752
Other comprehensive income (loss), net of tax:
Unrealized income (loss) on investment	(255)	41	(270)	239
Reclassification adjustment for gain realized on sale of investments	0	(1,171)	0	(1,171)
COMPREHENSIVE INCOME	$ 7,206	$ 5,716	$ 11,886	$ 6,820
EARNINGS PER SHARE
Basic (usd per share)	$ 0.37	$ 0.34	$ 0.60	$ 0.38
Diluted (usd per share)	0.36	0.34	0.59	0.38
DIVIDENDS PER SHARE (usd per share)	$ 0.20	$ 0.19	$ 0.39	$ 0.38
WEIGHTED AVERAGE SHARES OUTSTANDING
Basic (shares)	20,357,068	20,214,349	20,342,064	20,204,655
Diluted (shares)	20,501,437	20,398,002	20,490,938	20,391,692