CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Plant and property, at original cost:
Electric	$ 2,207,736	$ 2,176,188
Gas	72,127	69,851
Other	39,095	37,983
Construction work in progress	129,219	56,347
Total plant and property, Gross	2,448,177	2,340,369
Accumulated depreciation and amortization	718,492	682,737
Total plant and property, Net	1,729,685	1,657,632
Current assets:
Cash and cash equivalents	16,383	3,375
Restricted cash	1,773	4,357
Accounts receivable - trade, net of allowance $988 and $1,388, respectively	51,485	38,874
Accrued unbilled revenues	16,335	23,254
Accounts receivable - other	14,900	13,277
Fuel, materials and supplies	53,050	61,870
Prepaid expenses and other	20,360	21,806
Unrealized gain in fair value of derivative contracts	333	96
Regulatory assets	6,398	6,377
Total current assets	181,017	173,286
Noncurrent assets and deferred charges:
Regulatory assets	231,950	243,958
Goodwill	39,492	39,492
Unamortized debt issuance costs	8,722	7,606
Unrealized gain in fair value of derivative contracts		191
Other	4,942	4,204
Total noncurrent assets and deferred charges	285,106	295,451
Total Assets	2,195,808	2,126,369
Capitalization and Liabilities
Common stock, $1 par value, 42,939,207 and 42,484,363 shares issued and outstanding, respectively	42,939	42,484
Capital in excess of par value	637,003	628,199
Retained earnings	63,350	47,115
Total common stockholders' equity	743,292	717,798
Long-term debt (net of current portion):
Obligations under capital lease	4,237	4,441
First mortgage bonds and secured debt	637,569	487,541
Unsecured debt	101,680	199,644
Total long-term debt	743,486	691,626
Total long-term debt and common stockholders' equity	1,486,778	1,409,424
Current liabilities:
Accounts payable and accrued liabilities	55,281	66,559
Current maturities of long-term debt	327	714
Short-term debt		24,000
Regulatory liabilities	4,295	6,303
Customer deposits	12,518	12,001
Interest accrued	13,766	5,902
Other current liabilities	1,894
Unrealized loss in fair value of derivative contracts	3,078	3,403
Taxes accrued	16,781	2,992
Total current liabilities	107,940	121,874
Commitments and contingencies (Note 7)
Noncurrent liabilities and deferred credits:
Regulatory liabilities	134,531	131,055
Deferred income taxes	320,042	301,967
Unamortized investment tax credits	18,708	18,897
Pension and other postretirement benefit obligations	107,299	120,808
Unrealized loss in fair value of derivative contracts	3,089	3,819
Other	17,421	18,525
Total noncurrent liabilities and deferred credits	601,090	595,071
Total Capitalization and Liabilities	$ 2,195,808	$ 2,126,369