Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Operating Revenues
Member electric sales	$ 292,259	$ 275,517	$ 574,674	$ 547,286
Non-member electric sales	25,313	25,054	60,471	55,176
Other	21,329	20,051	42,185	41,622
Total revenues	338,901	320,622	677,330	644,084
Operating expenses
Purchased power	82,356	76,558	158,775	147,593
Fuel	58,508	51,560	119,321	112,550
Production	61,088	57,016	110,649	107,998
Transmission	40,486	39,132	74,286	75,592
General and administrative	4,841	6,392	12,021	11,502
Depreciation, amortization, and depletion	41,090	41,873	87,762	80,776
Coal mining	9,584	7,398	17,760	15,671
Other	3,978	3,690	8,768	9,020
Operating expenses	301,931	283,619	589,342	560,702
Operating margins	36,970	37,003	87,988	83,382
Other income
Interest	1,135	1,059	2,220	2,133
Capital credits from cooperatives	151	184	4,397	4,695
Membership withdrawal	2,500		5,000
Other income	409	694	1,429	1,735
Total other income	4,195	1,937	13,046	8,563
Interest expense, net of amounts capitalized	36,299	35,924	72,648	71,344
Income tax expense (benefit)	(302)	350	(604)	350
Net margins including noncontrolling interest	5,168	2,666	28,990	20,251
Net income attributable to noncontrolling interest	(377)	(129)	(673)	(181)
Net margins attributable to the Association	$ 4,791	$ 2,537	$ 28,317	$ 20,070