INCOME TAXES (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 61,000	$ 57,000
State income taxes [Abstract]
Current	526,000	145,000	106,000
Deferred	706,000	1,312,000	994,000
Total state income tax expense	1,232,000	1,457,000	1,100,000
Federal income taxes [Abstract]
Current	1,199,000	1,795,000	0
Deferred	3,157,000	3,364,000	3,554,000
Total federal income tax expense	4,356,000	5,159,000	3,554,000
Reconciliation of effective tax rate [Abstract]
Income before federal and state income taxes	13,890,000	16,460,000	11,401,000
Income before federal and state income taxes (in hundredths)	100.00%	100.00%	100.00%
Amount computed at statutory rate	4,722,000	5,596,000	3,876,000
Amount computed at statutory rate (in hundredths)	34.00%	34.00%	34.00%
Reconciling Items [Abstract]
State income tax-net of federal tax benefit	804,000	952,000	711,000
State income tax-net of federal tax benefit (in hundredths)	5.80%	5.80%	6.20%
Other	62,000	68,000	67,000
Other (in hundredths)	0.40%	0.40%	0.60%
Total income tax expense	5,588,000	6,616,000	4,654,000
Total effective income tax rate (in hundredths)	40.20%	40.20%	40.80%
Deferred tax assets related to [Abstract]
Federal alternative minimum tax credit carry-forwards	4,643,000	5,031,000	3,688,000
Federal and state operating loss carry-forwards	544,000	481,000	3,077,000
Bad debt allowance	88,000	96,000	127,000
Valuation allowance	(61,000)	(57,000)	(53,000)
Stock options	343,000	294,000	251,000
Other	264,000	326,000	344,000
Total deferred tax assets	5,821,000	6,171,000	7,434,000
Deferred tax liabilities related to [Abstract]
Property plant and equipment basis differences	(55,066,000)	(51,687,000)	(48,681,000)
Expenses of rate proceedings	(86,000)	(53,000)	(144,000)
Property taxes	(592,000)	(496,000)	(494,000)
Other	(657,000)	(651,000)	(619,000)
Total deferred tax liabilities	(56,401,000)	(52,887,000)	(49,938,000)
Net deferred tax liability	(50,580,000)	(46,716,000)	(42,504,000)
Deferred taxes, which are classified into a net current and non-current balance, are presented in the balance sheet as follows [Abstract]
Current deferred tax liability	(838,000)	(837,000)	(772,000)
Non-current deferred tax liability	(49,742,000)	(45,879,000)	(41,732,000)
Net deferred tax liability	(50,580,000)	(46,716,000)	(42,504,000)
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning Of Period	57,000	53,000	45,000
Additions Charged to Costs and Expenses	4,000	4,000	8,000
Deductions	0	0	0
Balance at End of Period	61,000	57,000	53,000
Federal Authorities [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carry-forwards	0
Income tax examination description	for tax years 2010 through 2013
State Authorities [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carry-forwards	$ 9,700,000
Income tax examination description	for tax years 2010 through 2013