Regulated Operating Expenses (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Regulated Operating Expenses
Electric transmission and distribution expense	$ 7,463	$ 5,530	$ 21,139	$ 16,509	$ 26,492	$ 20,828
Natural gas transmission and distribution expense	569	681	1,801	1,803	2,496	2,376
Power operation expense (other than fuel)	4,183	3,942	12,195	11,953	15,885	15,766
Customer accounts and assistance expense	2,772	3,124	8,492	8,322	11,350	10,894
Employee pension expense	2,735	2,662	7,963	8,062	10,638	10,605
Employee healthcare expense	2,486	2,662	6,817	7,857	9,150	10,678
General office supplies and expense	3,088	2,997	10,465	9,589	13,725	12,560
Administrative and general expense	3,307	3,375	10,970	11,292	14,479	14,917
Allowance for uncollectible accounts	915	975	3,017	2,765	3,917	3,489
Regulatory reversal of gain on sale of assets	44		44	1,236	44	1,236
Miscellaneous expense	125	152	350	496	526	675
Total	$ 27,687	$ 26,100	$ 83,253	$ 79,884	$ 108,702	$ 104,024