Consolidated Statements of Revenues and Expenses - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Operating revenues:
Sales to Members	$ 379,154	$ 311,148	$ 727,251	$ 619,924
Sales to non-Members	189	32,593	253	63,595
Total operating revenues	379,343	343,741	727,504	683,519
Operating expenses:
Fuel	126,588	115,211	225,540	223,620
Production	103,180	128,369	206,651	243,128
Depreciation and amortization	54,401	42,952	107,887	85,604
Purchased power	13,002	14,612	26,145	28,243
Accretion	8,024	6,477	16,040	12,859
Deferral of Hawk Road and Smith Energy Facilities effect on net margin		(27,374)		(41,689)
Total operating expenses	305,195	280,247	582,263	551,765
Operating margin	74,148	63,494	145,241	131,754
Other income:
Investment income	12,727	10,185	25,050	20,034
Other	2,427	2,441	4,728	5,300
Total other income	15,154	12,626	29,778	25,334
Interest charges:
Interest expense	91,005	88,132	179,522	175,839
Allowance for debt funds used during construction	(27,945)	(26,699)	(54,325)	(52,952)
Amortization of debt discount and expense	2,965	3,835	5,947	7,980
Net interest charges	66,025	65,268	131,144	130,867
Net margin	$ 23,277	$ 10,852	$ 43,875	$ 26,221