Accounting policies (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2007 gal
Cash and Restricted Cash Equivalents Held In Foreign Bank	$ 36,100,000
Restricted Cash and Cash Equivalents		7,500,000
Deposits Pledged As Collateral		7,500,000
Interest Costs Capitalized		246,851
Amount Of Water Lost {in gallons}			438,000,000
Other assets	2,706,185	2,855,471
Accumulated Amortization of Other Deferred Costs	1,100,000	923,000
Fair Value Inputs, Control Premium	32.60%
Equity Method Investment, Additional Information	The Company uses the equity method of accounting for investments in common stock where the Company holds 20% to 50% of the voting stock of the investee and has significant influence over its operating and financial policies but does not meet the criteria for consolidation.
Crieteria For Recognising Investment At Cost	Investments where the Company does not exercise significant influence over the operating and financial policies of the investee and holds less than 20% of the voting stock are recorded at cost.
Impaired Assets to be Disposed of by Method Other than Sale, Amount of Impairment Loss	432,727
Cash Deposits In Excess Of Federally Insured Limits	303,000
Estimated Fair Value Percentage Of Services Unit	The fair value the Company estimated for its services unit for the year ended December 31, 2012 was 10% less than its carrying amount.
Goodwill, Impairment Loss	88,717
Retail [Member]
Estimated Fair Value Carrying Amount Exceeded Percentage	39.00%
Bulk [Member]
Estimated Fair Value Carrying Amount Exceeded Percentage	6.00%
Services [Member]
Estimated Fair Value Carrying Amount Exceeded Percentage	10.00%
Capitalized Engineering Labor and Materials Cost [Member]
Other assets	$ 3,500,000	$ 3,500,000