Statement of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
OPERATING REVENUES	$ 473,406	$ 474,029	$ 472,994
OPERATING EXPENSES:
General and administrative	54,512	52,343	57,105
Operation and maintenance	78,085	79,514	73,128
Depreciation and amortization	102,084	101,672	100,554
Regulatory debits	4,857	3,510	2,550
Taxes, other than income taxes	17,889	17,835	17,151
Regulatory charge resulting from Tax Reform (Note 1)	206,547	0	0
Other expenses, net	195	0	0
Total operating expenses	464,169	254,874	250,488
OPERATING INCOME	9,237	219,155	222,506
OTHER (INCOME) AND OTHER EXPENSES:
Interest expense	33,015	39,164	46,024
Allowance for equity and borrowed funds used during construction	(1,444)	(1,371)	(1,619)
Miscellaneous other (income) expenses, net	5,500	907	(595)
Total other (income) and other expenses	37,071	38,700	43,810
NET INCOME (LOSS)	(27,834)	180,455	178,696
CASH FLOW HEDGES:
Amortization of cash flow hedges into Interest expense	0	(28)	(62)
COMPREHENSIVE INCOME (LOSS)	$ (27,834)	$ 180,427	$ 178,634