CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
OPERATING ACTIVITIES:
Net Income	$ 32,043	$ 32,575
Items not affecting cash:
Depreciation	26,433	25,315
Amortization of debt issue costs, discount and deferred hedge gain	90	398
Amortization of restricted stock	1,075	560
Equity portion of allowance for funds used during construction	(930)	(261)
Gain on disposition of assets	(56)	0
Deferred income taxes	20,195	19,596
Changes in current assets and liabilities:
Restricted cash	3,681	266
Accounts receivable	15,639	(1,421)
Inventories	17,856	23,848
Other current assets	1,153	(2,765)
Accounts payable	(16,099)	(17,369)
Accrued expenses	19,812	26,490
Regulatory assets	6,718	6,123
Regulatory liabilities	(794)	6,014
Other noncurrent assets	(13,717)	(2,751)
Other noncurrent liabilities	6,826	5,462
Cash provided by operating activities	119,925	122,080
INVESTING ACTIVITIES:
Property, plant, and equipment additions	(47,107)	(37,580)
Proceeds from sale of assets	80	0
Cash used in investing activities	(47,027)	(37,580)
FINANCING ACTIVITIES:
Treasury stock activity	75	55
Dividends on common stock	(13,358)	(12,975)
Repayments on long-term debt	(3,795)	(3,623)
Line of credit borrowings	0	80,000
Line of credit repayments	0	(233,000)
(Repayments) issuances of short-term borrowings, net	(53,956)	85,989
Cash used in financing activities	(71,034)	(83,554)
Increase in Cash and Cash Equivalents	1,864	946
Cash and Cash Equivalents, beginning of period	5,928	6,234
Cash and Cash Equivalents, end of period	7,792	7,180
Cash (received) paid during the period for:
Income taxes	(335)	0
Interest	8,806	9,584
Significant non-cash transactions:
Capital expenditures included in accounts payable and accrued expenses	$ 5,823	$ 1,695