CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
OPERATING ACTIVITIES:
Net Income	$ 58,440	$ 54,788
Items not affecting cash:
Depreciation	75,562	68,697
Amortization of debt issue costs, discount and deferred hedge gain	914	1,428
Amortization of restricted stock	1,649	1,264
Equity portion of allowance for funds used during construction	(960)	(4,597)
Loss on disposition of assets	850	716
Deferred income taxes	31,310	31,213
Changes in current assets and liabilities:
Restricted cash	1,188	2,241
Accounts receivable	36,192	45,117
Inventories	(21,346)	(17,391)
Other current assets	(1,896)	6,021
Accounts payable	(12,808)	(31,371)
Accrued expenses	37,018	41,108
Regulatory assets	5,539	(8,247)
Regulatory liabilities	2,663	(12,551)
Other noncurrent assets	(3,451)	10,923
Other noncurrent liabilities	(359)	(1,049)
Cash provided by operating activities	210,505	188,310
INVESTING ACTIVITIES:
Property, plant, and equipment additions	(124,484)	(178,147)
Proceeds from sale of assets	209	69
Cash used in investing activities	(124,275)	(178,078)
FINANCING ACTIVITIES:
Treasury stock activity	169	(127)
Dividends on common stock	(38,930)	(36,728)
Issuance of long-term debt	0	225,000
Repayment on long-term debt	(6,586)	(231,141)
Line of credit borrowings	80,000	554,000
Line of credit repayments	(233,000)	(511,000)
Issuances of short-term borrowings, net	112,993	0
Financing costs	(1,116)	(8,019)
Cash used in financing activities	(86,470)	(8,015)
(Decrease) Increase in Cash and Cash Equivalents	(240)	2,217
Cash and Cash Equivalents, beginning of period	6,234	4,344
Cash and Cash Equivalents, end of period	5,994	6,561
Cash paid during the period for:
Income taxes	18	1,000
Interest	28,950	31,637
Significant non-cash transactions:
Capital expenditures included in accounts payable	$ 4,314	$ 4,416