Statements of Consolidated Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash Flows from Operating Activities:
Net Income	$ 91,608	$ 89,291	$ 66,652
Loss from Discontinued Operations	1,168	568	633
Income from Continuing Operations	92,776	89,859	67,285
Adjustments to Reconcile Income from Continuing Operations to Net Cash Provided by Operating Activities:
Depreciation and Amortization	55,089	47,759	44,694
Net Unrealized Loss (Gain) on Derivatives - Energy Related	193	(5,377)	22,624
Unrealized (Gain) Loss on Derivatives - Other	(660)	149	641
Unrealized Loss on Property, Plant and Equipment	3,506	0	0
Provision for Losses on Accounts Receivable	4,932	2,272	4,943
CIP Receivable	(18,106)	(1,289)	4,381
Deferred Gas Costs - Net of Recoveries	25,050	(37,343)	22,492
Deferred SBC Costs - Net of Recoveries	(4,183)	(4,402)	(2,344)
Stock-Based Compensation Expense	2,992	2,511	2,047
Deferred and Noncurrent Income Taxes - Net	20,306	23,303	28,895
Environmental Remediation Costs - Net	(186)	(13,608)	(3,520)
Gas Plant Cost of Removal	(2,133)	(1,590)	(1,596)
Pension Contribution (See Note 1)	(25,000)	0	(8,000)
Changes in:
Accounts Receivable	(59,701)	90,407	(76,634)
Inventories	13,481	1,905	32,421
Prepaid and Accrued Taxes - Net	(4,635)	5,398	(10,483)
Accounts Payable and Other Accrued Liabilities	18,829	(6,131)	37,595
Derivatives - Energy Related	306	740	(9,645)
Other Assets and Liabilities (See Note 1)	(4,211)	(2,245)	4,485
Cash Flows from Discontinued Operations	(819)	(961)	(1,187)
Net Cash Provided by Operating Activities	117,826	191,357	159,094
Cash Flows from Investing Activities:
Capital Expenditures	(253,845)	(193,119)	(166,910)
Proceeds from Sale of Property, Plant and Equipment	29	3,500	0
Net Proceeds from (Purchase of) Sale of Restricted Investments in Margin Accounts	755	(10,269)	(3,174)
Investment in Long-Term Receivables	(6,243)	(4,926)	(3,313)
Proceeds from Long-Term Receivables	8,182	6,312	2,901
Purchase of Company Owned Life Insurance	(4,547)	(4,628)	(4,354)
Investment in Affiliate	(39,431)	(23,043)	(4,750)
Return on Investment in Affiliate	0	2,339	0
Advances on Notes Receivable - Affiliate	(67,943)	(41,612)	(101,957)
Repayment of Notes Receivable - Affiliate	13,402	47,694	5,834
Other	(6,276)	(6,423)	(2,843)
Net Cash Provided by (Used In) Investing Activities	(355,917)	(224,175)	(278,566)
Cash Flows from Financing Activities:
Net Borrowings from Short-Term Credit Facilities	17,500	70,714	54,087
Proceeds from Issuance of Long-Term Debt	235,000	0	115,000
Payments for Issuance of Long-Term Debt	(1,788)	(43)	(1,215)
Principal Repayments of Long-Term Debt	(35,000)	(25,000)	(10,000)
Premium for Early Retirement of Debt	(700)	0	0
Dividends on Common Stock	(50,942)	(44,975)	(40,478)
Proceeds from Sale of Common Stock	70,241	13,436	0
Proceeds from Finance Obligation	0	23,482	0
Other	880	379	618
Net Cash Provided by (Used in) Financing Activities	235,191	37,993	118,012
Net (Decrease) Increase in Cash and Cash Equivalents	(2,900)	5,175	(1,460)
Cash and Cash Equivalents at Beginning of Period	7,538	2,363	3,823
Cash and Cash Equivalents at End of Period	4,638	7,538	2,363
Cash paid during the year for:
Interest (Net of Amounts Capitalized)	18,442	25,303	21,850
Income Taxes (Net of Refunds)	218	(9,861)	12,120
Supplemental Disclosures of Non-Cash Investing Activities
Capital Expenditures acquired on account but unpaid as of year-end	34,086	20,457	15,404
Reclass from Notes Receivable Affiliate to Investment in Affiliates	2,952	5,351	0
Notes Receivable Affiliate Exchanged for Accounts Receivable	$ 0	$ 1,783	$ 0