Aquisitions Pro Forma Summary for Prior Year (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Operating Revenues	$ 22,545,000	$ 21,348,000	$ 42,274,000	$ 39,888,000
Regulated Operating Revenue, Other	309,000	324,000	708,000	673,000
Revenues	24,331,000	24,488,000	45,848,000	44,712,000
Net Income	4,310,000	4,163,000	6,923,000	6,073,000
Earnings Per Share, Basic	$ 0.40	$ 0.48	$ 0.64	$ 0.70
Earnings Per Share, Diluted	$ 0.39	$ 0.47	$ 0.63	$ 0.69
Biddeford and Saco Water Company Acquisition [Member]
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Operating Revenues	1,110,000	22,465,000	2,039,000	41,955,000
Regulated Operating Revenue, Other	0	324,000	0	673,000
Real Estate Revenue, Net	0	1,450,000	0	1,450,000
Sales Revenue, Services, Net	9,000	1,394,000	63,000	2,767,000
Revenues	1,119,000	25,633,000	2,102,000	46,845,000
Net Income	$ 52,000	$ 4,235,000	$ (99,000)	$ 6,135,000
Earnings Per Share, Basic	$ 0.00	$ 0.49	$ (0.01)	$ 0.71
Earnings Per Share, Diluted		$ 0.48		$ 0.70