SCHEDULE II - Valuation and Qualifying Accounts (Details) - Reserve deducted from assets: accumulated provision for uncollectible accounts. - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Valuation and Qualifying Accounts
Balance At Beginning Of Period	$ 1,020,637	$ 1,025,177	$ 1,387,673
Charged To Income	2,266,976	3,463,797	2,213,988
Charged to Other Accounts	2,079,751	2,128,325	2,013,959
Deductions From Reserve	4,744,648	5,596,662	4,590,443
Balance At Close of Period	$ 622,716	$ 1,020,637	$ 1,025,177