QUALIFYING ACCOUNTS (Details) - Allowance for doubtful accounts - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Valuation and Qualifying Accounts
Balance at Beginning of Period	$ 366,105	$ 343,805	$ 380,708
Additions, Charged to Costs and Expenses	201,622	308,401	189,946
Deductions	194,899	286,101	226,849
Balance at end of Period	$ 372,828	$ 366,105	$ 343,805