CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Current assets
Cash and cash equivalents		$ 1,079	$ 1,285
Accounts receivable, net	[1]	56,378	60,396
Accrued unbilled revenues		47,698	53,567
Inventories		21,559	24,685
Regulatory assets		16,146	20,036
Prepaid taxes		25,976	28,628
Deferred income taxes		3,138	8,201
Prepayments and other		2,387	6,918
Total current assets		174,361	203,716
Property, plant and equipment, net		1,828,079	1,674,281
Other assets
Regulatory assets		289,196	280,693
Other investments		4,042	3,818
Other		5,211	4,612
Total other assets		298,449	289,123
Total assets		2,300,889	2,167,120
Current liabilities
Current portion of long-term debt		1,131	1,235
Short-term debt		10,000	78,000
Notes payable to affiliates		500	500
Accounts payable		34,317	61,530
Accounts payable to affiliates		24,538	26,524
Dividends payable to parent		15,322	14,957
Regulatory liabilities		11,781	16,940
Environmental liabilities		17,155	29,116
Accrued interest		7,945	7,658
Other		15,778	12,265
Total current liabilities		138,467	248,725
Deferred credits and other liabilities
Deferred Tax Liabilities, Net, Noncurrent		393,569	348,180
Deferred investment tax credits		8,560	9,089
Regulatory liabilities		141,289	132,674
Environmental liabilities		77,441	78,620
Customer advances		18,480	17,623
Pension and employee benefit obligations		49,889	51,313
Other		16,347	16,151
Total deferred credits and other liabilities		$ 705,575	$ 653,650
Commitments and contingencies
Capitalization
Long-term debt		$ 666,462	$ 567,056
Common stock — 1,000,000 shares authorized of $100 par value; 933,000 shares outstanding at Dec. 31, 2015 and 2014, respectively		93,300	93,300
Additional paid in capital		394,553	322,276
Retained earnings		302,741	282,398
Accumulated other comprehensive loss		(209)	(285)
Total common stockholder’s equity		790,385	697,689
Total liabilities and equity		$ 2,300,889	$ 2,167,120

[1] Accounts receivable, net includes an immaterial amount due from affiliates for 2015 and 2014, respectively.