CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Plant and property, at original cost:
Electric	$ 2,452,856	$ 2,420,824
Gas	82,363	79,364
Other	41,757	41,394
Construction work in progress	184,640	112,097
Total plant and property, Gross	2,761,616	2,653,679
Accumulated depreciation and amortization	753,309	743,407
Total plant and property, Net	2,008,307	1,910,272
Current assets:
Cash and cash equivalents	1,860	2,105
Restricted cash	4,726	4,726
Accounts receivable - trade, net of allowance $873 and $1,021, respectively	51,239	45,444
Accrued unbilled revenues	16,336	25,945
Accounts receivable - other	25,681	41,256
Fuel, materials and supplies	60,295	57,799
Prepaid expenses and other	31,220	27,879
Unrealized gain in fair value of derivative contracts	2,135	3,901
Regulatory assets	7,306	10,752
Total current assets	200,798	219,807
Noncurrent assets and deferred charges:
Regulatory assets	202,139	209,717
Goodwill	39,492	39,492
Unamortized debt issuance costs	8,829	8,821
Other	3,278	2,147
Total noncurrent assets and deferred charges	253,738	260,177
Total Assets	2,462,843	2,390,256
Capitalization and liabilities
Common stock, $1 par value, 43,760,441 and 43,479,186 shares issued and outstanding, respectively	43,760	43,479
Capital in excess of par value	655,777	649,543
Retained earnings	102,926	90,276
Total common stockholders' equity	802,463	783,298
Long-term debt (net of current portion):
Obligations under capital lease	3,646	3,875
First mortgage bonds and secured debt	757,643	697,615
Unsecured debt	101,710	101,699
Total long-term debt	862,999	803,189
Total long-term debt and common stockholders' equity	1,665,462	1,586,487
Current liabilities:
Accounts payable and accrued liabilities	54,337	83,420
Current maturities of long-term debt	304	292
Short-term debt	16,250	44,000
Regulatory liabilities	6,356	7,898
Customer deposits	14,271	13,747
Interest accrued	15,159	6,565
Unrealized loss in fair value of derivative contracts	4,371	6,469
Taxes accrued	19,719	3,380
Other current liabilities	513	356
Total current liabilities	$ 131,280	$ 166,127
Commitments and contingencies (Note 7)
Noncurrent liabilities and deferred credits:
Regulatory liabilities	$ 136,165	$ 128,471
Deferred income taxes	409,134	377,452
Unamortized investment tax credits	18,260	18,367
Pension and other postretirement benefit obligations	74,739	93,863
Unrealized loss in fair value of derivative contracts	3,061	3,243
Other	24,742	16,246
Total noncurrent liabilities	666,101	637,642
Total Capitalization and Liabilities	$ 2,462,843	$ 2,390,256