Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Operating revenues
Other	$ 16,226	$ 12,128	$ 37,150	$ 39,540
Operating revenues	401,601	399,053	1,034,723	1,053,558
Operating expenses
Purchased power	103,136	103,525	260,804	252,948
Fuel	65,061	67,374	165,679	204,271
Production	39,698	48,619	122,595	148,457
Transmission	43,989	42,305	127,175	122,329
General and administrative	17,081	12,978	49,337	35,887
Depreciation, amortization and depletion	45,775	40,590	137,110	116,879
Coal mining	4,200	1,675	8,021	7,824
Other	2,691	4,640	13,429	12,154
Operating expenses	321,631	321,706	884,150	900,749
Operating margins	79,970	77,347	150,573	152,809
Other income
Interest	959	1,364	3,248	4,156
Capital credits from cooperatives	1,186	1,186	4,674	4,520
Other income (expense)	197	14,314	348	16,226
Total other income	2,342	16,864	8,270	24,902
Interest expense
Interest	37,673	39,991	114,533	120,754
Interest charged during construction	(1,460)	(1,961)	(5,022)	(6,800)
Interest expense, net of amounts capitalized	36,213	38,030	109,511	113,954
Income tax benefit	(154)	(77)	(484)	(231)
Net margins including noncontrolling interest	46,253	56,258	49,816	63,988
Net margin attributable to noncontrolling interest	(1,424)	(1,113)	(4,164)	(3,239)
Net margins attributable to the Association	44,829	55,145	45,652	60,749
Utility Member electric sales
Operating revenues
Operating revenues	346,769	358,586	926,529	942,175
Non-member electric sales
Operating revenues
Operating revenues	$ 38,606	$ 28,339	$ 71,044	$ 71,843