STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities
Net income	$ 93,660	$ 90,835
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	43,846	38,890
Deferred income taxes	4,828	24,077
Share-based compensation expense	1,954	1,945
Provision for doubtful accounts	2,263	2,722
Changes in assets and liabilities:
Accounts receivable	(44,924)	(7,447)
Materials and supplies	(2,562)	4,610
Natural gas in storage	55,820	79,598
Asset removal costs	(11,169)	(7,436)
Accounts payable	(53,172)	(56,409)
Accrued taxes other than income	4,263	6,147
Customer deposits	1,218	1,050
Regulatory assets and liabilities	29,090	83,724
Other assets and liabilities	(2,824)	(39,022)
Cash provided by operating activities	122,291	223,284
Investing activities
Capital expenditures	(83,303)	(86,599)
Other	(3,040)	0
Cash used in investing activities	(86,343)	(86,599)
Financing activities
Repayments of notes payable, net	(4,000)	(74,608)
Dividends paid	(26,343)	(24,137)
Tax withholdings related to net share settlements of stock compensation	(7,300)	(7,817)
Cash used in financing activities	(37,643)	(106,562)
Change in cash and cash equivalents	(1,695)	30,123
Cash and cash equivalents at beginning of period	21,323	14,413
Cash and cash equivalents at end of period	19,628	44,536
Common Stock [Member]
Operating activities
Net income	$ 0	$ 0