Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating activities:
Net Income	$ 41,537	$ 40,310
Adjustments to reconcile net income to cash provided by operations:
Depreciation and amortization	20,985	21,085
Regulatory amortization of gas reserves	4,073	4,107
Deferred income taxes	13,327	20,445
Qualified defined benefit pension plan expense	1,435	1,316
Contributions to qualified defined benefit pension plans	(1,720)	(3,220)
Deferred environmental expenditures, net	(1,280)	(3,432)
Amortization of environmental remediation	4,624	6,954
Increase (Decrease) in Regulatory Liabilities	6,424	0
Other	451	1,695
Changes in assets and liabilities:
Receivables, net	12,485	23,147
Inventories	13,173	5,645
Income taxes	(6,531)	4,504
Accounts payable	(19,868)	(13,437)
Interest accrued	2,489	4,615
Deferred gas costs	3,519	13,454
Other, net	9,398	17,978
Cash provided by operating activities	104,521	145,166
Investing activities:
Capital expenditures	(57,431)	(38,924)
Other	(57)	98
Cash used in investing activities	(57,488)	(38,826)
Financing activities:
Repurchases related to stock-based compensation	0	(1,943)
Long-term debt retired	22,000	0
Change in short-term debt	(4,200)	(53,300)
Cash dividend payments on common stock	(12,781)	(13,456)
Other	(309)	(523)
Cash used in financing activities	(39,290)	(69,222)
Increase in cash and cash equivalents	7,743	37,118
Cash and cash equivalents, beginning of period	3,472	3,521
Cash and cash equivalents, end of period	11,215	40,639
Supplemental disclosure of cash flow information:
Interest paid, net of capitalization	6,261	4,394
Income taxes paid	$ 9,800	$ 3,040