Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Operating Activities:
Net Margin including Non-controlling Interest	$ 8,067	$ 7,375
Adjustments to reconcile net margin to net cash provided by operating activities:
Depreciation and amortization	31,082	31,050
Other non-cash charges	8,282	7,737
Amortization of lease obligations	3,363	3,141
Interest on lease deposits	(1,977)	(1,931)
Change in current assets	37,670	6,848
Change in deferred energy	(12,884)	5,443
Change in current liabilities	(25,332)	78,718
Change in regulatory assets and liabilities	(4,070)	(10,217)
Change in deferred charges and credits	3,734	5,262
Net Cash Provided by Operating Activities	47,935	133,426
Financing Activities:
Issuance of long-term debt	350,000
Debt issuance costs	(2,342)
Payments of long-term debt	(216,000)
Draws on revolving credit facilities	52,257	85,408
Payments on revolving credit facilities	(59,300)	(112,362)
Net Cash Provided by (Used for) Financing Activities	124,615	(26,954)
Investing Activities:
Purchase of held to maturity securities	(108,121)
Proceeds from held to maturity securities	99,221
Proceeds from sale of trading securities	11,089
Increase in other investments	(3,287)	(2,583)
Electric plant additions	(27,295)	(65,613)
Amortization of loss on auction rate securities recorded as a regulatory asset	4,181
Gain on investments	(3,227)
Net Cash Used for Investing Activities	(27,439)	(68,196)
Net Change in Cash and Cash Equivalents	145,111	38,276
Cash and Cash Equivalents - Beginning of Period	4,391	6,278
Cash and Cash Equivalents - End of Period	$ 149,502	$ 44,554