Statement of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
OPERATING REVENUES	$ 115,569	$ 115,946	$ 236,017	$ 235,210
OPERATING EXPENSES:
General and administrative	13,038	14,276	26,865	29,199
Operation and maintenance	21,231	18,168	38,483	35,317
Depreciation	25,414	25,078	50,729	50,159
Regulatory debits	871	586	1,720	1,184
Taxes, other than income taxes	4,312	4,551	8,664	8,912
Total operating expenses	64,866	62,659	126,461	124,771
OPERATING INCOME	50,703	53,287	109,556	110,439
OTHER (INCOME) AND OTHER EXPENSES:
Interest expense	10,952	11,511	22,429	23,019
Allowance for equity and borrowed funds used during construction	(242)	(332)	(625)	(471)
Miscellaneous other (income) expenses, net	31	(1)	669	(626)
Total other (income) and other expenses	10,741	11,178	22,473	21,922
NET INCOME	39,962	42,109	87,083	88,517
CASH FLOW HEDGES:
Amortization of cash flow hedges into Interest expense	(13)	(16)	(28)	(31)
COMPREHENSIVE INCOME	$ 39,949	$ 42,093	$ 87,055	$ 88,486