Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net margin	$ 21,454	$ 20,598
Adjustments to reconcile net margin to net cash provided by operating activities:
Depreciation and amortization, including nuclear fuel	92,049	87,413
Accretion cost	8,998	8,016
Amortization of deferred gains	(447)	(447)
Allowance for equity funds used during construction	(193)	(177)
Deferred outage costs	(19,385)	(24,869)
(Gain) loss on sale of investments	(16,045)	849
Regulatory deferral of costs associated with nuclear decommissioning	10,602	(5,814)
Other	(3,138)	(1,685)
Change in operating assets and liabilities:
Receivables	6,241	4,044
Inventories	(12,028)	5,253
Prepayments and other current assets	3,822	273
Accounts payable	(18,028)	(39,787)
Accrued interest	(35,292)	(5,528)
Accrued taxes	(12,909)	(13,160)
Other current liabilities	(7,059)	(9,777)
Member power bill prepayments	1,717	(6,779)
Total adjustments	(1,095)	(2,175)
Net cash provided by operating activities	20,359	18,423
Cash flows from investing activities:
Property additions	(171,806)	(259,447)
Activity in nuclear decommissioning trust fund - Purchases	(165,213)	(129,886)
Activity in nuclear decommissioning trust fund - Proceeds	163,635	128,179
Decrease (increase) in restricted cash and investments	36,990	(9,419)
(Increase) decrease in restricted short-term investments	(3)	2,663
Activity in other long-term investments - Purchases	(18,190)	(14,267)
Activity in other long-term investments - Proceeds	14,093	11,639
Other	(1,658)	3,147
Net cash used in investing activities	(142,152)	(267,391)
Cash flows from financing activities:
Long-term debt proceeds	4,517	7,998
Long-term debt payments	(201,398)	(36,677)
Increase in short-term borrowings, net	226,722	171,280
Other	4,213	4,422
Net cash provided by financing activities	34,054	147,023
Net decrease in cash and cash equivalents	(87,739)	(101,945)
Cash and cash equivalents at beginning of period	366,290	213,038
Cash and cash equivalents at end of period	278,551	111,093
Cash paid for -
Interest (net of amounts capitalized)	94,754	66,950
Supplemental disclosure of non-cash investing and financing activities:
Change in asset retirement obligations		(10,425)
Change in accrued property additions	40,259	(79,336)
Interest paid-in-kind	$ 13,909	$ 10,606