Statements of Comprehensive Income (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Net income	$ 4,830,780	$ 4,716,530
Other comprehensive income:
Unrealized gain on marketable securities during period	220,946	42,512
Income tax expense related to other comprehensive income	(76,579)	(14,735)
Other comprehensive income, net of tax	144,367	27,777
Comprehensive income	$ 4,975,147	$ 4,744,307