Consolidated Statements of Comprehensive Income (Parenthetical) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]
Income tax (benefit) expense on unrealized holding (loss) income arising during the period	$ 2,258,082	$ (1,725,094)
Income tax (benefit) expense on reclassification adjustment for (losses) gains	$ (30,101)	$ 455,792