Net Income Per Share - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Schedule Of Earnings Per Share [Line Items]
Shares controlled by Employee Stock Ownership Plan (ESOP)	296,095	395,587
Options Expiring November 2020 [Member]
Schedule Of Earnings Per Share [Line Items]
Options excluded from computation of earnings per share	64,821
Options purchase price per diluted share	$ 10.35
Options Expiring November 2020 [Member] | Stock Option 1 [Member]
Schedule Of Earnings Per Share [Line Items]
Options excluded from computation of earnings per share		85,919
Options purchase price per diluted share		$ 10.35
Options Expiring November 2021 [Member]
Schedule Of Earnings Per Share [Line Items]
Options excluded from computation of earnings per share	77,872	91,948
Options purchase price per diluted share	$ 11.00	$ 11.00
Options Expiring November 2022 [Member]
Schedule Of Earnings Per Share [Line Items]
Options excluded from computation of earnings per share	189,699
Options purchase price per diluted share	$ 10.50