CONDENSED CONSOLIDATED STATEMENTS OF INCOME (LOSS) Unaudited - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Operating revenue	$ 122,036	$ 121,727
Operations:
Water production costs	42,068	41,069
Administrative and general	25,249	27,827
Other operations	16,124	19,302
Maintenance	6,112	6,063
Depreciation and amortization	19,201	16,046
Income tax benefit	(884)	(925)
Property and other taxes	6,116	6,075
Total operating expenses	113,986	115,457
Net operating income (loss)	8,050	6,270
Other income and expenses:
Non-regulated revenue	3,462	3,428
Non-regulated expenses	(2,054)	(2,980)
Allowance for equity funds used during construction (Note 2)	779	0
Income tax expense on other income and expenses	(889)	(181)
Net other income	1,298	267
Interest expense:
Interest expense	8,710	8,065
Allowance for borrowed funds used during construction (Note 2)	(494)	(730)
Net interest expense	8,216	7,335
Net income (loss)	$ 1,132	$ (798)
Earnings (loss) per share:
Basic (in dollars per share)	$ 0.02	$ (0.02)
Diluted (in dollars per share)	$ 0.02	$ (0.02)
Weighted average shares outstanding:
Basic (in shares)	47,984	47,905
Diluted (in shares)	47,984	47,905
Dividends declared per share of common stock (in dollars per share)	$ 0.1800	$ 0.1725