Investment Securities - Amortized Cost and Fair Value of Securities Available For Sale, By Contractual Maturity (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Due in one year or less, Amortized Cost	$ 1,749,000
Due after one year through five years, Amortized Cost	801,000
Due after five years through ten years, Amortized Cost	70,281,000
Due after ten years, Amortized Cost	27,401,000
Amortized Cost, Total	100,232,000
Available-for-sale securities, Amortized Cost	183,060,000	173,190,000
Due in one year or less, Fair Value	1,796,000
Due after one year through five years, Fair Value	830,000
Due after five years through ten years, Fair Value	69,098,000
Due after ten years, Fair Value	27,919,000
Fair Value, Total	99,643,000
Available-for-sale (at fair value)	181,347,703	178,207,974
Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Amortized Cost	82,655,000	77,513,000
Available-for-sale (at fair value)	81,503,000	78,678,000
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Amortized Cost	173,000	183,000
Available-for-sale (at fair value)	$ 202,000	$ 205,000