STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Document Fiscal Year Focus	2017
Operating activities
Net income	$ 115,876	$ 97,781
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	113,293	106,490
Deferred income taxes	61,329	59,771
Share-based compensation expense	6,930	9,341
Provision for doubtful accounts	4,508	3,521
Changes in assets and liabilities:
Accounts receivable	158,747	107,762
Materials and supplies	(4,705)	3,227
Natural gas in storage	(32,209)	(2,077)
Asset removal costs	(37,928)	(40,715)
Accounts payable	(65,983)	(32,923)
Accrued interest	(11,112)	(11,182)
Accrued taxes other than income	2,087	2,670
Accrued liabilities	(4,396)	(13,658)
Customer deposits	(1,566)	100
Regulatory assets and liabilities	11,448	(18,726)
Other assets and liabilities	(13,915)	19,053
Cash provided by operating activities	302,404	290,435
Investing activities
Capital expenditures	(249,057)	(231,336)
Other	617	492
Cash used in investing activities	(248,440)	(230,844)
Financing activities
Repayments of notes payable, net	29,000	28,500
Repurchase of common stock	(17,512)	(24,066)
Proceeds from Issuance of Common Stock	2,208	1,983
Dividends paid	(65,996)	(54,923)
Tax withholdings related to net share settlements of stock compensation	(9,455)	(9,005)
Cash used in financing activities	(61,755)	(57,511)
Change in cash and cash equivalents	(7,791)	2,080
Cash and cash equivalents at beginning of period	14,663	2,433
Cash and cash equivalents at end of period	$ 6,872	$ 4,513