Summary of Activity for Company's Non-vested Options (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013
Number of Shares
Non-vested options at January 1, 2013	54,416
Granted	20,229
Vested	(29,110)
Forfeited or expired	0
Non-vested options at September 30, 2013	45,535
Weighted Average Grant-Date Fair Value
Non-vested options at January 1, 2013	$ 7.56
Granted	$ 7.99
Vested	$ 7.34
Forfeited or expired	$ 0
Non-vested options at September 30, 2013	$ 7.89