CONSOLIDATED BALANCE SHEETS (UNAUDITED) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets
Cash and cash equivalents	$ 4,170	$ 4,459
Accounts receivable, net	61,160	50,706	[1]
Accrued unbilled revenues	40,579	49,138
Inventories	15,052	19,685
Regulatory assets	13,162	12,048
Prepaid taxes	17,416	24,688
Deferred income taxes	3,494	0
Prepayments and other	2,916	4,394
Total current assets	157,949	165,118
Property, plant and equipment, net	1,317,605	1,298,236
Other assets
Regulatory assets	238,541	240,459
Other investments	3,328	3,232
Other	3,841	4,040
Total other assets	245,710	247,731
Total assets	1,721,264	1,711,085
Current liabilities
Current portion of long-term debt	103	1,246
Short-term debt	21,000	39,000
Notes payable to affiliates	550	550
Accounts payable	23,109	30,723
Accounts payable to affiliates	28,843	31,556
Dividends payable to parent	7,519	7,667
Regulatory liabilities	7,337	6,086
Environmental liabilities	23,200	23,427
Accrued interest	7,359	7,304
Other	13,178	11,794
Total current liabilities	132,198	159,353
Deferred credits and other liabilities
Deferred income taxes	273,592	261,800
Deferred investment tax credits	9,103	8,911
Regulatory liabilities	125,500	123,746
Environmental liabilities	85,774	84,655
Customer advances	15,904	15,631
Pension and employee benefit obligations	52,768	63,643
Other	8,655	8,923
Total deferred credits and other liabilities	571,296	567,309
Commitments and contingencies
Capitalization
Long-term debt	468,479	467,317
Common stock - 1,000,000 shares authorized of $100 par value; 933,000 shares outstanding at March 31, 2013 and Dec. 31, 2012, respectively	93,300	93,300
Additional paid in capital	209,867	189,867
Retained earnings	246,542	234,376
Accumulated other comprehensive loss	(418)	(437)
Total common stockholder's equity	549,291	517,106
Total liabilities and equity	$ 1,721,264	$ 1,711,085

[1] Accounts receivable, net includes $586 due from affiliates as of Dec. 31, 2012.