Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flows from operating activities:
Net income	$ 36,827	$ 34,238
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of electric plant in service	38,930	40,121
Amortization of Nuclear Fuel	21,897	21,807
Deferred income taxes, net	16,888	18,630
Allowance for equity funds used during construction	(5,178)	(4,170)
Other amortization and accretion	8,258	6,804
Other operating activities	(87)	937
Change in:
Accounts receivable	(43,626)	(19,197)
Inventories	(2,047)	(1,087)
Net overcollection (undercollection) of fuel revenues	(8,940)	15,594
Prepayments and other	(8,022)	(5,456)
Accounts payable	2,733	(4,748)
Taxes accrued	(250)	(6,661)
Other current liabilities	1,150	779
Deferred charges and credits	(7,146)	(5,695)
Net cash provided by operating activities	51,387	91,896
Cash flows from investing activities:
Cash additions to utility property, plant and equipment	(110,279)	(99,929)
Cash additions to nuclear fuel	(16,879)	(38,155)
Capitalized interest and AFUDC:
Utility property, plant and equipment	(8,319)	(6,633)
Nuclear fuel	(2,609)	(2,668)
Allowance for equity funds used during construction	5,178	4,170
Decommissioning trust funds:
Purchases, including funding of $2.3 million, respectively	(26,914)	(64,011)
Sales and maturities	22,362	59,513
Other investing activities	3,419	978
Net cash used for investing activities	(134,041)	(146,735)
Cash flows from financing activities:
Dividends paid	(20,714)	(18,834)
Borrowings under the revolving credit facility:
Proceeds	28,486	121,964
Payments	(24,322)	(44,583)
Other financing activities	(207)	(1,832)
Net cash provided (used for) financing activities	(16,757)	56,715
Net increase (decrease) in cash and cash equivalents	(99,411)	1,876
Cash and cash equivalents at beginning of period	111,057	8,208
Cash and cash equivalents at end of period	$ 11,646	$ 10,084