Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Revenues
Member electric sales	$ 1,134,781	$ 1,125,699	$ 1,101,471
Non-member electric sales	132,208	120,234	197,497
Other	86,989	89,515	96,123
Total revenues	1,353,978	1,335,448	1,395,091
Operating expenses
Purchased power	341,289	305,045	327,445
Fuel	235,645	231,537	293,033
Production	218,008	235,398	229,933
Transmission	156,713	153,443	145,396
General and administrative	26,320	24,708	28,591
Depreciation, amortization, and depletion	173,969	152,718	128,712
Coal mining	36,929	36,130	40,849
Other	18,099	18,500	19,255
Operating expenses	1,206,972	1,157,479	1,213,214
Operating margins	147,006	177,969	181,877
Other income
Interest Income	4,368	4,355	11,076
Capital credits from cooperatives	20,349	9,189	8,684
Other income	3,934	3,981	3,573
Total other income	28,651	17,525	23,333
Interest expense, net of amounts capitalized	144,877	142,570	142,357
Income taxes	(1,417)	0	0
Net margins including noncontrolling interest	32,197	52,924	62,853
Net (income) loss attributable to noncontrolling interest	(449)	489	1,383
Net margins attributable to the Association	$ 31,748	$ 53,413	$ 64,236