Activity of Non-Vested Stock Options (Detail) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Number of Shares
Nonvested common stock options, beginning balance	673,833	872,373
Common stock options granted		205,000
Common stock options vested	(542,433)	(383,208)
Common stock options forfeited		(20,332)
Nonvested common stock options, ending balance	131,400	673,833
Weighted Average Exercise Price Per Share
Nonvested common stock options, beginning balance	$ 6.59	$ 5.41
Common stock options granted		$ 9.52
Common stock options vested	$ 5.95	$ 5.47
Common stock options forfeited		$ 3.62
Nonvested common stock options, ending balance	$ 8.53	$ 6.59