CONSOLIDATED BALANCE SHEETS (UNAUDITED) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Current assets
Cash and cash equivalents	$ 2,347		$ 1,349
Accounts receivable, net	72,991	[1]	59,269	[1]
Accrued unbilled revenues	39,441		51,634
Inventories	14,495		21,475
Regulatory assets	29,551		14,866
Prepaid taxes	16,317		27,518
Deferred income taxes	11,225		14,953
Prepayments and other	4,531		5,056
Total current assets	190,898		196,120
Property, plant and equipment, net	1,475,375		1,442,779
Other assets
Regulatory assets	245,745		233,193
Other investments	3,691		3,650
Other	3,573		3,651
Total other assets	253,009		240,494
Total assets	1,919,282		1,879,393
Current liabilities
Current portion of long-term debt	1,218		107
Short-term debt	79,000		68,000
Notes payable to affiliates	470		470
Accounts payable	51,671		52,086
Accounts payable to affiliates	26,993		24,986
Dividends payable to parent	8,057		8,032
Regulatory liabilities	5,605		9,717
Taxes accrued	9,214		5,638
Environmental liabilities	34,679		28,785
Accrued interest	7,488		7,507
Other	8,248		9,376
Total current liabilities	232,643		214,704
Deferred credits and other liabilities
Deferred income taxes	312,657		305,139
Deferred investment tax credits	9,529		9,698
Regulatory liabilities	131,445		126,424
Environmental liabilities	82,060		79,703
Customer advances	16,098		16,008
Pension and employee benefit obligations	37,701		45,708
Other	9,276		9,237
Total deferred credits and other liabilities	598,766		591,917
Commitments and contingencies
Capitalization
Long-term debt	467,394		468,490
Common stock — 1,000,000 shares authorized of $100 par value; 933,000 shares outstanding at March 31, 2014 and Dec. 31, 2013, respectively	93,300		93,300
Additional paid in capital	248,844		248,844
Retained earnings	278,678		262,499
Accumulated other comprehensive loss	(343)		(361)
Total common stockholder’s equity	620,479		604,282
Total liabilities and equity	$ 1,919,282		$ 1,879,393

[1] Accounts receivable, net includes $48 and $1,595 due from affiliates as of March 31, 2014 and Dec. 31, 2013, respectively.