CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011
Operating revenues:
Electric and water	$ 119,726	$ 128,360	$ 515,641	$ 499,042
Gas	15,683	20,989	41,124	47,314
Other	1,735	1,379	6,521	5,754
Total operating revenues	137,144	150,728	563,286	552,110
Operating revenue deductions:
Fuel and purchased power	45,229	54,217	191,268	202,831
Cost of natural gas sold and transported	8,581	12,040	19,302	23,545
Regulated operating expenses	23,348	19,715	89,075	80,090
Other operating expenses	598	475	2,221	1,937
Maintenance and repairs	9,124	9,242	40,923	38,206
Loss on plant disallowance			150
Depreciation and amortization	14,935	17,333	61,138	62,804
Provision for income taxes	6,084	7,269	32,886	27,850
Other taxes	8,435	8,589	30,426	28,582
Total operating revenue deductions	116,334	128,880	467,389	465,845
Operating income	20,810	21,848	95,897	86,265
Other income and (deductions):
Allowance for equity funds used during construction	50		343	2,797
Interest income	179	23	712	129
Benefit/(provision) for other income taxes	(115)	24	(366)	6
Other - non-operating expense, net	(227)	(285)	(1,224)	(1,077)
Total other income and (deductions)	(113)	(238)	(535)	1,855
Interest charges:
Long-term debt	10,654	10,633	42,603	42,107
Trust preferred securities				1,027
Short-term debt	30	31	85	417
Allowance for borrowed funds used during construction	(48)	(23)	(243)	(3,245)
Other	257	(953)	63	(2,918)
Total interest charges	10,893	9,688	42,508	37,388
Net income	$ 9,804	$ 11,922	$ 52,854	$ 50,732
Weighted average number of common shares outstanding - basic	42,047	41,665	41,946	41,300
Weighted average number of common shares outstanding - diluted	42,075	41,707	41,968	41,324
Total earnings per weighted average share of common stock - basic and diluted (in dollars per share)	$ 0.23	$ 0.29	$ 1.26	$ 1.23
Dividends declared per share of common stock (in dollars per share)	$ 0.25	$ 0.32	$ 0.57	$ 1.28