Consolidated Statements of Revenues and Expenses - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Operating revenues:
Sales to Members	$ 430,883	$ 318,123	$ 1,158,134	$ 938,047
Sales to non-Members	130	50,541	383	114,136
Total operating revenues	431,013	368,664	1,158,517	1,052,183
Operating expenses:
Fuel	178,516	142,142	404,056	365,762
Production	105,681	94,504	312,332	337,632
Depreciation and amortization	54,719	42,484	162,606	128,088
Purchased power	13,109	13,737	39,254	41,980
Accretion	8,059	6,676	24,099	19,535
Deferral of Hawk Road and Smith Energy Facilities effect on net margin		(166)		(41,855)
Total operating expenses	360,084	299,377	942,347	851,142
Operating margin	70,929	69,287	216,170	201,041
Other income:
Investment income	12,578	9,816	37,628	29,850
Other	1,531	2,227	6,259	7,527
Total other income	14,109	12,043	43,887	37,377
Interest charges:
Interest expense	93,544	89,322	273,066	265,161
Allowance for debt funds used during construction	(30,135)	(27,739)	(84,460)	(80,691)
Amortization of debt discount and expense	2,999	3,839	8,946	11,819
Net interest charges	66,408	65,422	197,552	196,289
Net margin	$ 18,630	$ 15,908	$ 62,505	$ 42,129