Stock-Based Compensation - Recognized Financial Statements for Stock Options, Stock Appreciation Rights, and Restricted Stock (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Total Cost of Share-Based Plans Charged Against Income Before Tax Effect	$ 728,833	$ 419,836	$ 1,350,557	$ 1,021,955
Income Tax Expense Recognized in Income	$ (281,147)	$ (161,952)	$ (520,977)	$ (394,219)