OTHER INCOME AND EXPENSES (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other income and expenses
Revenue	$ 17,318	$ 14,795	$ 16,686
Expense	14,285	11,265	11,553
Operating and Maintenance
Other income and expenses
Revenue	9,748	8,028	9,938
Expense	10,256	9,119	10,976
Leases
Other income and expenses
Revenue	2,029	1,938	1,956
Expense	208	243	153
Design and Construction
Other income and expenses
Revenue	1,258	1,374	1,407
Expense	1,102	1,173	1,135
Meter Reading and Billing
Other income and expenses
Revenue	803	1,313	1,255
Expense	615	1,055	882
Interest Income
Other income and expenses
Revenue	186	70	41
Change in value of life insurance contracts (gain) loss
Other income and expenses
Expense	(994)	(1,878)	(2,504)
Other non-regulated income and expenses
Other income and expenses
Revenue	3,294	2,072	2,089
Expense	$ 3,098	$ 1,553	$ 911