CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Operating revenues
Electric	$ 211,097	$ 190,811
Natural gas	73,791	50,357
Other	254	247
Total operating revenues	285,142	241,415
Operating expenses
Electric fuel and purchased power, non-affiliates	8,851	4,170
Purchased power, affiliates	109,571	98,942
Cost of natural gas sold and transported	51,142	30,985
Operating and maintenance expenses	44,231	41,676
Conservation program expenses	2,672	2,992
Depreciation and amortization	19,307	18,855
Taxes (other than income taxes)	6,797	6,394
Total operating expenses	242,571	204,014
Operating income	42,571	37,401
Other income, net	124	115
Allowance for funds used during construction — equity	1,572	946
Interest charges and financing costs
Interest charges — includes other financing costs of $374 and $381, respectively	6,867	6,855
Allowance for funds used during construction — debt	(758)	(409)
Total interest charges and financing costs	6,109	6,446
Income before income taxes	38,158	32,016
Income taxes	13,923	12,331
Net income	$ 24,235	$ 19,685