Schedule II - Valuation And Qualifying Accounts (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Valuation and Qualifying Accounts [Abstract]
Balance at beginning of period	$ 98,006,927	$ 92,592,971	$ 88,804,628
Provision	10,648,966	7,640,454	5,722,492
Write offs	(706,055)	(2,226,498)	(1,934,149)
Balance at end of period	$ 107,949,839	$ 98,006,927	$ 92,592,971