CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities
Net income	$ 59,468	$ 49,951	$ 51,006
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	78,048	70,372	69,900
Deferred income taxes	25,789	27,107	35,610
Amortization of investment tax credits	(664)	(626)	(611)
Allowance for equity funds used during construction	(4,259)	(2,104)	(1,007)
Provision for bad debts	3,988	3,329	3,842
Net derivative (gains) losses	(279)	127	127
Changes in operating assets and liabilities:
Accounts receivable	(12,702)	(15,953)	(4,013)
Accrued unbilled revenues	(2,496)	(470)	2,911
Inventories	(1,879)	6,018	913
Other current assets	(3,749)	(3,172)	(1,180)
Accounts payable	(1,811)	5,828	(16,614)
Net regulatory assets and liabilities	(2,062)	3,623	10,008
Other current liabilities	7,589	3,681	(2,260)
Pension and other employee benefit obligations	(8,759)	(10,857)	(7,214)
Change in other noncurrent assets	232	14	564
Change in other noncurrent liabilities	1,119	(595)	(2,682)
Net cash provided by operating activities	137,573	136,273	139,300
Investing activities
Utility capital/construction expenditures	(201,278)	(152,759)	(140,982)
Allowance for equity funds used during construction	4,259	2,104	1,007
Other, net	(421)	916	(112)
Net cash used in investing activities	(197,440)	(149,739)	(140,087)
Financing activities
Proceeds from (repayments of) short-term borrowings, net	29,000	(27,000)	66,000
Proceeds from notes payable to affiliates	0	50	111,300
Repayments Of Notes Payable To Affiliates	(80)	0	(148,350)
Proceeds from Issuance of Long-term Debt	0	97,916	0
Repayments of long-term debt	(160)	(97)	(96)
Capital contributions from parent	58,977	2,796	0
Dividends paid to parent	(30,980)	(57,311)	(32,941)
Net cash provided by (used in) financing activities	56,757	16,354	(4,087)
Net change in cash and cash equivalents	(3,110)	2,888	(4,874)
Cash and cash equivalents at beginning of period	4,459	1,571	6,445
Cash and cash equivalents at end of period	1,349	4,459	1,571
Supplemental disclosure of cash flow information:
Cash paid for interest (net of amounts capitalized)	(24,376)	(21,035)	(22,616)
Cash (paid) received for income taxes, net	(9,842)	(5,841)	1,116
Supplemental disclosure of non-cash investing transactions:
Property, plant and equipment additions in accounts payable	$ 27,222	$ 10,618	$ 9,427