Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
OPERATING ACTIVITIES:
Net income	$ 51,149	$ 47,121
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation	25,461	25,315
Regulatory debits	1,247	849
Amortization of deferred charges and credits	173	(165)
Allowance for equity funds used during construction	(110)	(262)
Changes in current assets and liabilities:
Trade and other accounts receivable	150	1,061
Affiliated receivables	(215)	(261)
Exchange gas due from others	1,574	771
Materials and supplies	(31)	(26)
Other current assets	(277)	1,495
Trade accounts payable	(2,949)	(2,062)
Affiliated payables	(2,366)	(1,308)
Exchange gas due to others	(1,573)	(771)
Other accrued liabilities	11,196	12,285
Changes in noncurrent assets and liabilities:
Deferred charges	820	(1,341)
Noncurrent liabilities	2,554	2,650
Net cash provided by operating activities	86,803	85,351
FINANCING ACTIVITIES:
Cash distributions to parent	(50,000)	(57,000)
Net cash used in financing activities	(50,000)	(57,000)
Property, plant and equipment:
Capital expenditures, net of equity AFUDC	(12,389)	(12,327)
Contributions and advances for construction costs	(417)	379
Disposal of property, plant and equipment, net	50	(66)
Advances to affiliates, net	(24,047)	(26,154)
Proceeds from insurance	0	9,776
Net cash provided by (used in) investing activities	(36,803)	(28,392)
NET INCREASE (DECREASE) IN CASH	0	(41)
CASH AT BEGINNING OF PERIOD	0	169
CASH AT END OF PERIOD	0	128
Increases to property, plant and equipment	(14,768)	(5,759)
Changes in related in accounts receivable, accounts payable, and accrued liabilities	2,379	(6,568)
Capital expenditures, net of equity AFUDC	$ (12,389)	$ (12,327)