Regulated Operating Expenses (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Regulated Operating Expenses
Electric transmission and distribution expense	$ 3,418	$ 3,144	$ 7,240	$ 5,971	$ 14,265	$ 11,697
Natural gas transmission and distribution expense	579	515	1,141	1,046	2,289	2,133
Power operation expense (other than fuel)	2,469	2,791	5,147	5,695	10,807	11,884
Customer accounts and assistance expense	2,395	2,998	4,931	5,917	10,632	11,326
Employee pension expense	1,975	1,287	3,819	2,751	6,967	5,622
Employee healthcare plan	1,716	1,696	3,337	3,246	7,022	6,463
General office supplies and expense	2,236	2,705	5,135	5,381	11,338	10,626
Administrative and general expense	3,057	3,218	6,704	6,634	12,966	12,995
Allowance for uncollectible accounts	1,242	855	1,324	1,455	3,520	2,780
Miscellaneous expense	(2)	63	23	93	98	172
Total	$ 19,085	$ 19,272	$ 38,801	$ 38,189	$ 79,904	$ 75,698