Amortized Costs and Fair Values of Securities Available for Sale by Contractual Maturities (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Total	$ 57,929	$ 58,011
Total	57,504	57,336
US Government Agency Securities
Schedule of Available-for-sale Securities [Line Items]
Less than 1 year amortized cost	10,058	5,011
1-5 years amortized cost	12,356	17,845
5-10 years amortized cost	1,000	1,174
Less than 1 year fair value	10,127	5,050
1-5 years fair value	12,732	18,346
5-10 years fair value	1,000	1,210
Mortgage Backed Securities
Schedule of Available-for-sale Securities [Line Items]
5-10 years amortized cost	7,158	7,794
Greater than 10 years amortized cost	6,298	5,138
5-10 years fair value	7,342	7,878
> 10 years fair value	6,467	5,301
Collateralized Mortgage Obligations
Schedule of Available-for-sale Securities [Line Items]
1-5 years amortized cost	326	480
5-10 years amortized cost	415	651
Greater than 10 years amortized cost	7,131	6,692
1-5 years fair value	328	481
5-10 years fair value	424	659
> 10 years fair value	7,196	6,752
Asset Backed Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Greater than 10 years amortized cost	2,578	2,548
> 10 years fair value	68	68
States and Municipal
Schedule of Available-for-sale Securities [Line Items]
1-5 years amortized cost	2,934	2,174
5-10 years amortized cost	7,675	7,850
Greater than 10 years amortized cost		654
1-5 years fair value	3,138	2,305
5-10 years fair value	8,682	8,585
> 10 years fair value		$ 701