OTHER INCOME AND EXPENSES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other income and expenses
Revenue	$ 15,898	$ 16,585	$ 15,624
Expense	9,390	11,445	14,044
Litigation gain		1,500
Operating and Maintenance
Other income and expenses
Revenue	8,621	8,430	9,385
Expense	8,847	9,061	10,438
Leases
Other income and expenses
Revenue	2,015	1,923	1,929
Expense	182	204	208
Design and Construction
Other income and expenses
Revenue	1,918	1,792	1,399
Expense	1,635	1,473	1,292
Meter Reading and Billing
Other income and expenses
Revenue	256	242	597
Expense	(6)	62	434
Interest Income
Other income and expenses
Revenue	68	18	39
Expense	0	0	0
Change in value of life insurance contracts (gain) loss
Other income and expenses
Revenue	0	0	0
Expense	(3,057)	(1,026)	218
Other non-regulated income and expenses
Other income and expenses
Revenue	3,020	4,180	2,275
Expense	$ 1,789	$ 1,671	$ 1,454