Statements of Comprehensive Income (Unaudited) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net income	$ 1,276,791	$ 1,116,161	$ 4,183,980	$ 3,537,875
Other comprehensive income:
Unrealized gain (loss) on marketable securities	70,568	150,846	(115,637)	315,379
Income tax (expense) benefit related to other comprehensive income	(25,008)	(52,429)	40,016	(109,457)
Other comprehensive income (loss), net of tax	45,560	98,417	(75,621)	205,922
Comprehensive income	$ 1,322,351	$ 1,214,578	$ 4,108,359	$ 3,743,797