Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating activities:
Net income	$ 43,039	$ 38,660
Adjustments to reconcile net income to cash provided by operations:
Depreciation and amortization	42,440	40,807
Regulatory amortization of gas reserves	8,031	7,647
Deferred income taxes	22,170	27,022
Qualified defined benefit pension plan expense	2,615	2,737
Contributions to qualified defined benefit pension plans	(7,250)	(6,120)
Deferred environmental expenditures, net	(6,817)	(5,521)
Regulatory disallowance of prior environmental cost deferrals	0	3,273
Amortization of environmental remediation	9,565	6,922
Other	1,268	2,121
Changes in assets and liabilities:
Receivables, net	86,065	87,271
Inventories	(3,537)	4,525
Income taxes	(5,243)	3,710
Accounts payable	(22,063)	(17,141)
Interest accrued	0	(80)
Deferred gas costs	15,325	(9,295)
Other, net	8,623	13,022
Cash provided by operating activities	194,231	199,560
Investing activities:
Capital expenditures	(94,318)	(62,153)
Other	(404)	2,453
Cash used in investing activities	(94,722)	(59,700)
Financing activities:
Repurchases related to stock-based compensation	(2,034)	(1,042)
Proceeds from stock options exercised	1,309	5,374
Change in short-term debt	(53,300)	(117,235)
Cash dividend payments on common stock	(26,919)	(25,677)
Other	(1,232)	(28)
Cash used in financing activities	(82,176)	(138,608)
Increase in cash and cash equivalents	17,333	1,252
Cash and cash equivalents, beginning of period	3,521	4,211
Cash and cash equivalents, end of period	20,854	5,463
Supplemental disclosure of cash flow information:
Interest paid, net of capitalization	18,011	18,124
Income taxes paid (refunded)	$ 9,081	$ (7,900)