CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Current assets
Cash and cash equivalents	$ 1,349		$ 4,459
Accounts receivable, net	59,269	[1]	50,706	[1]
Accrued unbilled revenues	51,634		49,138
Inventories	21,475		19,685
Regulatory assets	14,866		12,048
Prepaid taxes	27,518		24,688
Deferred income taxes	14,953		0
Prepayments and other	5,056		4,394
Total current assets	196,120		165,118
Property, plant and equipment, net	1,442,779		1,298,236
Other assets
Regulatory assets	233,193		240,459
Other investments	3,650		3,232
Other	3,651		4,040
Total other assets	240,494		247,731
Total assets	1,879,393		1,711,085
Current liabilities
Current portion of long-term debt	107		1,246
Short-term debt	68,000		39,000
Notes payable to affiliates	470		550
Accounts payable	52,086		30,723
Accounts payable to affiliates	24,986		31,556
Dividends payable to parent	8,032		7,667
Regulatory liabilities	9,717		6,086
Taxes accrued	5,638		839
Environmental liabilities	28,785		23,427
Accrued interest	7,507		7,304
Other	9,376		10,955
Total current liabilities	214,704		159,353
Deferred credits and other liabilities
Deferred income taxes	305,139		261,800
Deferred investment tax credits	9,698		8,911
Regulatory liabilities	126,424		123,746
Environmental liabilities	79,703		84,655
Customer advances	16,008		15,631
Pension and employee benefit obligations	45,708		63,643
Other	9,237		8,923
Total deferred credits and other liabilities	591,917		567,309
Commitments and contingencies
Capitalization
Long-term debt	468,490		467,317
Common stock — 1,000,000 shares authorized of $100 par value; 933,000 shares outstanding at Dec. 31, 2013 and 2012, respectively	93,300		93,300
Additional paid in capital	248,844		189,867
Retained earnings	262,499		234,376
Accumulated other comprehensive loss	(361)		(437)
Total common stockholder’s equity	604,282		517,106
Total liabilities and equity	$ 1,879,393		$ 1,711,085

[1] Accounts receivable, net includes $1,595 and $586 due from affiliates as of Dec. 31, 2013 and 2012, respectively.