CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
OPERATING ACTIVITIES:
Net Income	$ 45,580	$ 37,902
Items not affecting cash:
Depreciation	30,318	29,218
Amortization of debt issue costs, discount and deferred hedge gain	1,538	64
Amortization of restricted stock	824	669
Equity portion of allowance for funds used during construction	(1,079)	(1,234)
Gain on disposition of assets	(59)	0
Deferred income taxes	26,860	27,236
Changes in current assets and liabilities:
Restricted cash	(5,723)	(1,987)
Accounts receivable	3,763	409
Inventories	17,530	15,313
Other current assets	2,767	(2,069)
Accounts payable	(18,180)	(14,118)
Accrued expenses	34,060	24,025
Regulatory assets	(7,614)	12,598
Regulatory liabilities	1,950	1,292
Other noncurrent assets	(24,998)	(23,489)
Other noncurrent liabilities	4,698	6,051
Cash provided by operating activities	112,235	111,880
INVESTING ACTIVITIES:
Property, plant, and equipment additions	(51,677)	(38,114)
Asset acquisition	1,455	0
Proceeds from sale of assets	94	0
Cash used in investing activities	(50,128)	(38,114)
FINANCING ACTIVITIES:
Treasury stock activity	(1,012)	(1,249)
Proceeds from issuance of common stock, net	13,365	17,701
Dividends on common stock	(15,454)	(14,170)
Repayments on long-term debt	(40)	(37)
Repayments of short-term borrowings, net	(55,973)	(78,949)
Financing costs	(69)	0
Cash used in financing activities	(59,183)	(76,704)
Increase (Decrease) in Cash and Cash Equivalents	2,924	(2,938)
Cash and Cash Equivalents, beginning of period	16,557	9,822
Cash and Cash Equivalents, end of period	19,481	6,884
Cash paid during the period for:
Income taxes	13	38
Interest	11,747	11,826
Significant non-cash transactions:
Capital expenditures included in accounts payable and accrued expenses	$ 3,991	$ 6,810