Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Utility plant:
Electric plant in service	$ 2,821,451	$ 2,789,773
Less accumulated depreciation and amortization	(1,144,265)	(1,121,653)
Net plant in service	1,677,186	1,668,120
Construction work in progress	245,416	167,394
Nuclear fuel; includes fuel in process of $51,472 and $49,545, respectively	205,902	171,433
Less accumulated amortization	(82,109)	(59,882)
Net nuclear fuel	123,793	111,551
Net utility plant	2,046,395	1,947,065
Current assets:
Cash and cash equivalents	8,664	8,208
Accounts receivable, principally trade, net of allowance for doubtful accounts of $3,110 and $3,015, respectively	98,455	76,348
Accumulated deferred income taxes	17,959	13,752
Inventories, at cost	43,500	40,222
Income taxes receivable	861	2,269
Undercollection of fuel revenues	0	9,130
Prepayments and other	6,406	4,810
Total current assets	175,845	154,739
Deferred charges and other assets:
Decommissioning trust funds	186,724	167,963
Regulatory assets	103,446	101,027
Other	30,508	26,057
Total deferred charges and other assets	320,678	295,047
Total assets	2,542,918	2,396,851
Capitalization:
Common stock, stated value $1 per share, 100,000,000 shares authorized, 65,505,583 and 65,295,888 shares issued, and 103,709 and 156,185 restricted shares, respectively	65,609	65,452
Capital in excess of stated value	309,007	309,777
Retained earnings	944,340	887,174
Accumulated other comprehensive loss, net of tax	(64,035)	(77,505)
Total stockholders equity subtotal before treasury stock	1,254,921	1,184,898
Treasury stock, 25,492,919 shares at cost	(424,647)	(424,647)
Common stock equity	830,274	760,251
Long-term debt	849,838	816,497
Total capitalization	1,680,112	1,576,748
Current liabilities:
Current maturities of long-term debt	0	33,300
Short-term borrowings under the revolving credit facility	61,542	33,379
Accounts payable, principally trade	38,247	51,704
Taxes accrued	29,829	30,700
Interest accrued	12,592	12,123
Overcollection of fuel revenues	6,969	2,105
Other	25,120	21,921
Total current liabilities	174,299	185,232
Deferred credits and other liabilities:
Accumulated deferred income taxes	358,286	299,475
Accrued pension liability	119,138	129,627
Accrued postretirement benefit liability	104,842	100,455
Asset retirement obligation	59,572	56,140
Regulatory liabilities	21,830	21,049
Other	24,839	28,125
Total deferred credits and other liabilities	688,507	634,871
Commitments and contingencies
Total capitalization and liabilities	$ 2,542,918	$ 2,396,851