Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities:
Net income	$ 34,711	$ 36,827
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of electric plant in service	41,651	38,930
Amortization of nuclear fuel	21,877	21,897
Deferred income taxes, net	15,141	16,888
Allowance for equity funds used during construction	(6,367)	(5,178)
Other amortization and accretion	9,145	8,258
Gain on sale of property, plant and equipment	(2,083)	0
Other operating activities	(3,031)	(87)
Change in:
Accounts receivable	(33,585)	(43,626)
Inventories	(100)	(2,047)
Net undercollection of fuel revenues	(13,369)	(8,940)
Prepayments and other	(6,691)	(8,022)
Accounts payable	1,983	2,733
Other current liabilities	428	900
Deferred charges and credits	(2,739)	(7,146)
Net cash provided by operating activities	56,971	51,387
Cash flows from investing activities:
Cash additions to utility property, plant and equipment	(105,999)	(110,279)
Cash additions to nuclear fuel	(17,690)	(16,879)
Capitalized interest and AFUDC:
Utility property, plant and equipment	(10,018)	(8,319)
Nuclear fuel	(2,527)	(2,609)
Allowance for equity funds used during construction	6,367	5,178
Decommissioning trust funds:
Purchases, including funding of $2.3 million	(40,924)	(26,914)
Sales and maturities	36,374	22,362
Proceeds from sale of property, plant and equipment	2,377	0
Other investing activities	1,650	3,419
Net cash used for investing activities	(130,390)	(134,041)
Cash flows from financing activities:
Dividends paid	(21,969)	(20,714)
Borrowings under the revolving credit facility:
Proceeds	142,951	28,486
Payments	(59,531)	(24,322)
Other financing activities	(928)	(207)
Net cash provided by (used for) financing activities	60,523	(16,757)
Net decrease in cash and cash equivalents	(12,896)	(99,411)
Cash and cash equivalents at beginning of period	25,592	111,057
Cash and cash equivalents at end of period	$ 12,696	$ 11,646