Consolidated Statement of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating activities:
Net income	$ 63,898	$ 72,667	$ 75,122
Adjustments to reconcile net income to cash provided by operations:
Depreciation and amortization	70,004	65,124	62,814
Undistributed earnings from equity investments	1,329	(588)	(1,329)
Non-cash expenses related to qualified defined benefit pension plans	7,191	8,009	9,914
Contributions to qualified defined benefit pension plans	(22,045)	(10,000)	(25,000)
Deferred environmental expenditures	25,586	(7,826)	(10,069)
Settlement of interest rate hedge	0	0	(10,096)
Other	(1,049)	(2,265)	(3,461)
Changes in assets and liabilities:
Receivables	(6,246)	15,830	35,506
Inventories	6,022	572	15,110
Taxes accrued	34,189	(51,524)	23,461
Accounts payable	148	(11,846)	1,188
Interest accrued	675	(253)	8,582
Deferred gas costs	8,565	(26,090)	36,819
Deferred tax liabilities	46,877	76,410	36,775
Other - net	(1,682)	(1,751)	(15,001)
Cash provided by operating activities	233,462	126,469	240,335
Investing activities:
Capital expenditures	(100,534)	(248,505)	(135,124)
Utility gas reserves	(50,597)	0	0
Restricted cash	(3,076)	34,619	(30,524)
Other	1,142	1,015	3,507
Cash used in investing activities	(153,065)	(212,871)	(162,141)
Financing activities:
Common stock issued (purchased) - net	3,040	4,598	(375)
Long-term debt issued	90,000	0	125,000
Long-term debt retired	(10,000)	(35,000)	(300)
Change in short-term debt	(115,835)	155,435	(158,851)
Cash dividend payments on common stock	(46,690)	(44,652)	(42,415)
Other	1,464	1,046	263
Cash used in financing activities	(78,021)	81,427	(76,678)
Increase (decrease) in cash and cash equivalents	2,376	(4,975)	1,516
Cash and cash equivalents - beginning of period	3,457	8,432	6,916
Cash and cash equivalents - end of period	5,833	3,457	8,432
Supplemental disclosure of cash flow information:
Interest paid	41,413	41,037	36,762
Income taxes paid	$ 1,756	$ 22,600	$ 10,000