Statement of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
OPERATING REVENUES	$ 120,448	$ 119,264
OPERATING EXPENSES:
General and administrative	13,827	14,923
Operation and maintenance	17,252	17,149
Depreciation	25,315	25,081
Regulatory debits	849	598
Taxes, other than income taxes	4,352	4,361
Total operating expenses	61,595	62,112
OPERATING INCOME	58,853	57,152
OTHER (INCOME) AND OTHER EXPENSES:
Interest expense	11,477	11,508
Allowance for equity and borrowed funds used during construction	(383)	(139)
Miscellaneous other (income) expenses, net	638	(625)
Total other (income) and other expenses	11,732	10,744
NET INCOME	47,121	46,408
CASH FLOW HEDGES:
Amortization of cash flow hedges into Interest expense	(15)	(15)
COMPREHENSIVE INCOME	$ 47,106	$ 46,393