Consolidated Statements of Revenues and Expenses (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating revenues:
Total operating revenues	$ 341,674	$ 356,600
Operating expenses:
Fuel	71,156	98,992
Production	116,131	103,320
Depreciation and amortization	62,024	62,303
Purchased power	16,613	16,065
Accretion	13,235	9,888
Total operating expenses	279,159	290,568
Operating margin	62,515	66,032
Other income:
Investment income	12,934	16,735
Other	2,009	1,829
Total other income	14,943	18,564
Interest charges:
Interest expense	102,285	101,448
Allowance for debt funds used during construction	(51,030)	(43,426)
Amortization of debt discount and expense	2,999	2,978
Net interest charges	54,254	61,000
Net margin	23,204	23,596
Members
Operating revenues:
Total operating revenues	341,513	356,470
Non-Members
Operating revenues:
Total operating revenues	$ 161	$ 130