Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net income	$ 87,392	$ 86,027
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of electric plant in service	59,346	59,329
Amortization of Nuclear Fuel	33,621	33,278
Deferred income taxes, net	45,479	43,818
Allowance for equity funds used during construction	(7,465)	(6,589)
Other amortization and accretion	12,345	10,904
Gain on sale of assets	0	(1,346)
Other operating activities	(484)	782
Change in:
Accounts receivable	(35,097)	(22,107)
Inventories	(4,772)	(2,400)
Net overcollection (undercollection) of fuel revenues	(8,362)	13,994
Prepayments and other	(5,471)	(3,443)
Accounts payable	(3,729)	(6,757)
Taxes accrued	6,794	537
Interest accrued	2,244	469
Other current liabilities	7,410	3,199
Deferred charges and credits	(4,340)	(7,896)
Net cash provided by operating activities	184,911	201,799
Cash flows from investing activities:
Cash additions to utility property, plant and equipment	(165,303)	(144,576)
Cash additions to nuclear fuel	(19,895)	(41,747)
Capitalized interest and AFUDC:
Utility property, plant and equipment	(11,985)	(10,483)
Nuclear fuel	(3,911)	(3,992)
Allowance for equity funds used during construction	7,465	6,589
Decommissioning trust funds:
Purchases, including funding of $3.4 million, respectively	(36,413)	(80,870)
Sales and maturities	29,419	74,095
Proceeds from sale of assets	0	1,757
Other investing activities	4,856	1,524
Net cash used for investing activities	(195,767)	(197,703)
Cash flows from financing activities:
Dividends paid	(31,379)	(28,861)
Borrowings under the revolving credit facility:
Proceeds	34,167	204,373
Payments	(40,831)	(176,210)
Pollution control bonds:
Proceeds	0	92,535
Payments	0	(92,535)
Other financing activities	(210)	(2,942)
Net cash used for fnancing activities	(38,253)	(3,640)
Net increase (decrease) in cash and cash equivalents	(49,109)	456
Cash and cash equivalents at beginning of period	111,057	8,208
Cash and cash equivalents at end of period	$ 61,948	$ 8,664