Statements Of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net income	$ 99,600	$ 91,761
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of electric plant in service	71,941	66,994
Amortization of Nuclear Fuel	29,822	32,494
Deferred income taxes, net	24,369	47,457
Allowance for equity funds used during construction	(2,462)	(2,209)
Other amortization and accretion	15,427	14,934
Net gains on decommissioning trust funds	(9,683)	(9,122)
Other operating activities	31	(762)
Change in:
Accounts receivable	(33,958)	(39,298)
Inventories	(1,480)	(2,988)
Prepayments and other	(5,716)	(5,120)
Accounts payable	4,920	525
Taxes accrued	7,632	6,539
Interest accrued	8,491	5,741
Net over-collection of fuel revenues	3,680	13,888
Other current liabilities	9,185	(138)
Deferred charges and credits	(321)	(1,950)
Net cash provided by operating activities	221,478	218,746
Cash flows from investing activities:
Cash additions to utility property, plant and equipment	(171,433)	(148,436)
Cash additions to nuclear fuel	(28,769)	(31,618)
Insurance proceeds received for equipment	5,351	8,069
Capitalized interest and AFUDC:
Utility property, plant and equipment	(5,013)	(4,382)
Nuclear fuel and other	(4,067)	(3,831)
Allowance for equity funds used during construction	2,462	2,209
Decommissioning trust funds:
Purchases, including funding of $1.6 million and $3.4 million, respectively	(74,438)	(80,785)
Sales and maturities	70,156	76,498
Other investing activities	3,639	(204)
Net cash used for investing activities	(202,112)	(182,480)
Cash flows from financing activities:
Dividends paid	(42,898)	(39,747)
Borrowings under the revolving credit facility:
Proceeds	504,707	532,332
Payments	(658,878)	(446,005)
Other financing activities	(3,322)	(906)
Net cash used by financing activities	(10,391)	(37,626)
Net increase (decrease) in cash and cash equivalents	8,975	(1,360)
Cash and cash equivalents at beginning of period	6,990	8,420
Cash and cash equivalents at end of period	15,965	7,060
4.22% Senior Notes, due 2028
Cash flows from financing activities:
Proceeds from issuance of senior notes	125,000	0
4.07% RGRT Senior Notes, due 2025
Cash flows from financing activities:
Proceeds from issuance of senior notes	65,000	0
4.47% Senior Notes, Series B, due 2017
Cash flows from financing activities:
Payment on maturing senior notes	0	(50,000)
1.875% 2012 Series A Refunding Bonds, due 2032
Cash flows from financing activities:
Payment on maturing pollution control bonds	$ 0	$ (33,300)