Consolidated Statement of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Operating activities:
Net income	$ 42,016	$ 42,966
Adjustments to reconcile net income to cash provided by operations:
Depreciation and amortization	36,049	34,855
Deferred tax liabilities	28,676	27,516
Non-cash expenses related to qualified defined benefit pension plans	4,109	3,655
Contributions to qualified defined benefit pension plans	(18,400)	(16,445)
Deferred environmental expenditures	(3,925)	(1,770)
Other	1,459	(819)
Changes in assets and liabilities:
Receivables	114,117	79,711
Inventories	5,495	9,156
Taxes accrued	(1,616)	11,007
Accounts payable	(37,854)	(30,052)
Interest accrued	(250)	(55)
Deferred gas costs	(11,830)	2,682
Other - net	17,336	6,328
Cash provided by operating activities	175,382	168,735
Investing activities:
Capital expenditures	(61,552)	(47,815)
Utility gas reserves	(27,060)	(16,152)
Other	61	67
Cash used in investing activities	(88,551)	(63,900)
Financing activities:
Common stock issued (purchased) - net, including common stock expense	2,910	(70)
Long-term debt issued	0	0
Long-term debt retired	(40,000)	(10,000)
Change in short-term debt	(28,400)	(72,035)
Cash dividend payments on common stock	(23,839)	(23,204)
Other	667	717
Cash used in financing activities	(88,662)	(104,592)
Increase (decrease) in cash and cash equivalents	(1,831)	243
Cash and cash equivalents - beginning of period	5,833	3,457
Cash and cash equivalents - end of period	4,002	3,700
Supplemental disclosure of cash flow information:
Interest paid	21,652	20,770
Income taxes paid	$ 2,648	$ 1,522