CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 1,668	$ 1,546
Accounts receivable, net	64,898	54,031
Accrued unbilled revenues	40,652	53,638
Inventories	13,503	18,309
Regulatory assets	18,126	18,162
Prepaid taxes	20,414	25,915
Prepayments and other	4,831	3,785
Total current assets	164,092	175,386
Property, plant and equipment, net	1,972,130	1,947,637
Other assets
Regulatory assets	284,587	286,188
Other investments	3,003	2,844
Other	1,079	785
Total other assets	288,669	289,817
Total assets	2,424,891	2,412,840
Current liabilities
Current portion of long-term debt	1,110	1,123
Short-term debt	33,000	60,000
Notes payable to affiliates	500	500
Accounts payable	31,886	41,068
Accounts payable to affiliates	55,082	29,037
Dividends payable to parent	13,071	10,729
Regulatory liabilities	20,830	17,428
Environmental liabilities	40,413	41,438
Accrued interest	9,681	8,012
Other	15,128	26,484
Total current liabilities	220,701	235,819
Deferred credits and other liabilities
Deferred income taxes	442,771	430,593
Deferred investment tax credits	7,906	8,037
Regulatory liabilities	149,713	148,189
Environmental liabilities	21,827	23,003
Customer advances	18,780	19,425
Pension and employee benefit obligations	46,157	55,164
Other	18,695	18,814
Total deferred credits and other liabilities	705,849	703,225
Commitments and contingencies
Capitalization
Long-term debt	662,125	661,946
Common stock — 1,000,000 shares authorized of $100 par value; 933,000 shares outstanding at March 31, 2017 and Dec. 31, 2016, respectively	93,300	93,300
Additional paid in capital	410,315	395,315
Retained earnings	332,715	323,368
Accumulated other comprehensive loss	(114)	(133)
Total common stockholder’s equity	836,216	811,850
Total liabilities and equity	$ 2,424,891	$ 2,412,840