CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Operating revenues
Electric	$ 232,802	$ 232,216	$ 659,853	$ 646,619
Natural gas	14,394	13,646	81,768	72,671
Other	315	282	847	877
Total operating revenues	247,511	246,144	742,468	720,167
Operating expenses
Electric fuel and purchased power, non-affiliates	6,181	4,238	12,637	11,870
Purchased power, affiliates	106,697	105,734	314,948	311,301
Cost of natural gas sold and transported	6,032	6,081	40,582	35,964
Operating and maintenance expenses	51,808	49,235	150,880	148,370
Conservation expenses	3,298	3,308	9,529	9,468
Depreciation and amortization	27,979	24,700	82,656	72,869
Taxes (other than income taxes)	7,124	6,506	21,002	20,757
Total operating expenses	209,119	199,802	632,234	610,599
Operating income	38,392	46,342	110,234	109,568
Other income (expense), net	95	(102)	424	424
Allowance for funds used during construction — equity	1,705	1,241	4,743	2,969
Interest charges and financing costs
Interest charges — includes other financing costs of $465, $465, $1,382 and $1,388, respectively	8,647	8,613	25,985	25,800
Allowance for funds used during construction — debt	(726)	(525)	(2,025)	(1,264)
Total interest charges and financing costs	7,921	8,088	23,960	24,536
Income before income taxes	32,271	39,393	91,441	88,425
Income taxes	9,946	15,172	32,456	33,948
Net income	$ 22,325	$ 24,221	$ 58,985	$ 54,477