OTHER INCOME AND EXPENSES (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Other income and expenses
Revenue	$ 16,686	$ 16,160	$ 15,993
Expense	11,553	15,822	12,312
Operating and maintenance
Other income and expenses
Revenue	9,938	9,176	9,237
Expense	10,976	9,689	9,713
Meter reading and billing
Other income and expenses
Revenue	1,255	1,212	1,207
Expense	882	944	990
Leases
Other income and expenses
Revenue	1,956	1,892	2,162
Expense	153	330	877
Design and construction
Other income and expenses
Revenue	1,407	1,689	1,306
Expense	1,135	1,420	1,041
Interest income
Other income and expenses
Revenue	41	75	28
Change in value of life insurance contracts (gain) loss
Other income and expenses
Expense	(2,504)	1,876	(2,641)
Other non-regulated income and expenses
Other income and expenses
Revenue	2,089	2,116	2,053
Expense	$ 911	$ 1,563	$ 2,332