CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 1,231	$ 1,546
Accounts receivable, net	51,214	54,031
Accrued unbilled revenues	44,224	53,638
Inventories	20,107	18,309
Regulatory assets	18,165	18,162
Prepaid taxes	19,505	25,915
Prepayments and other	18,637	3,785
Total current assets	173,083	175,386
Property, plant and equipment, net	2,032,528	1,947,637
Other assets
Regulatory assets	276,009	286,188
Other investments	2,853	2,844
Other	1,147	785
Total other assets	280,009	289,817
Total assets	2,485,620	2,412,840
Current liabilities
Current portion of long-term debt	1,086	1,123
Short-term debt	92,000	60,000
Notes payable to affiliates	500	500
Accounts payable	51,387	41,068
Accounts payable to affiliates	26,655	29,037
Dividends payable to parent	11,397	10,729
Regulatory liabilities	26,025	17,428
Environmental liabilities	18,348	41,438
Accrued interest	9,503	8,012
Other	26,861	26,484
Total current liabilities	263,762	235,819
Deferred credits and other liabilities
Deferred income taxes	471,892	430,593
Deferred investment tax credits	7,645	8,037
Regulatory liabilities	152,665	148,189
Environmental liabilities	12,888	23,003
Customer advances	18,015	19,425
Pension and employee benefit obligations	46,827	55,164
Other	16,177	18,814
Total deferred credits and other liabilities	726,109	703,225
Commitments and contingencies
Capitalization
Long-term debt	662,455	661,946
Common stock — 1,000,000 shares authorized of $100 par value; 933,000 shares outstanding at Sept. 30, 2017 and Dec. 31, 2016, respectively	93,300	93,300
Additional paid in capital	411,025	395,315
Retained earnings	329,045	323,368
Accumulated other comprehensive loss	(76)	(133)
Total common stockholder’s equity	833,294	811,850
Total liabilities and equity	$ 2,485,620	$ 2,412,840