CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Operating revenues
Electric	$ 185,374	$ 179,105	$ 376,185	$ 361,106
Natural gas	24,555	14,830	74,912	56,322
Other	246	238	493	544
Total operating revenues	210,175	194,173	451,590	417,972
Operating expenses
Electric fuel and purchased power, non-affiliates	1,862	4,467	6,032	7,914
Purchased power, affiliates	100,043	98,813	198,985	197,980
Cost of natural gas sold and transported	14,302	7,123	45,287	34,002
Operating and maintenance expenses	42,992	42,492	84,668	80,992
Conservation program expenses	3,118	3,620	6,110	7,122
Depreciation and amortization	19,051	17,093	37,906	34,102
Taxes (other than income taxes)	6,341	6,217	12,735	12,598
Total operating expenses	187,709	179,825	391,723	374,710
Operating income	22,466	14,348	59,867	43,262
Other income (expense), net	155	(40)	270	460
Allowance for funds used during construction — equity	780	765	1,726	1,764
Interest charges and financing costs
Interest charges — includes other financing costs of $380, $384, $761 and $810, respectively	6,814	6,044	13,669	12,059
Allowance for funds used during construction — debt	(400)	(139)	(809)	(225)
Total interest charges and financing costs	6,414	5,905	12,860	11,834
Income before income taxes	16,987	9,168	49,003	33,652
Income taxes	6,443	3,426	18,774	13,032
Net income	$ 10,544	$ 5,742	$ 30,229	$ 20,620