Allowance for Loan Losses (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Ending allowance balance attributable to loans:
Individually evaluated for impairment	$ 1,651,000		$ 1,651,000		$ 1,658,000
Collectively evaluated for impairment	2,940,000		2,940,000		2,524,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	4,591,000	4,663,000	4,591,000	4,663,000
Allowance for loan losses:
Beginning balance	4,432,000	4,561,000	4,182,000	4,473,000
Provisions for loan losses	350,000	400,000	1,125,000	1,325,000
Charge-offs	(259,000)	(403,000)	(897,000)	(1,388,000)
Recoveries	68,000	105,000	181,000	253,000
Ending balance	4,591,000	4,663,000	4,591,000	4,663,000
Residential
Ending allowance balance attributable to loans:
Individually evaluated for impairment	267,000		267,000		183,000
Collectively evaluated for impairment	943,000		943,000		645,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	1,210,000	1,288,000	1,210,000	1,288,000
Allowance for loan losses:
Beginning balance	1,173,000	1,217,000	828,000	1,024,000
Provisions for loan losses	51,000	146,000	697,000	601,000
Charge-offs	(15,000)	(80,000)	(327,000)	(346,000)
Recoveries	1,000	5,000	12,000	9,000
Ending balance	1,210,000	1,288,000	1,210,000	1,288,000
Land
Ending allowance balance attributable to loans:
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	102,000		102,000		93,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	102,000	61,000	102,000	61,000
Allowance for loan losses:
Beginning balance	102,000	59,000	93,000	55,000
Provisions for loan losses	0	2,000	12,000	6,000
Charge-offs	0	0	(4,000)	0
Recoveries	0	0	1,000	0
Ending balance	102,000	61,000	102,000	61,000
Construction
Ending allowance balance attributable to loans:
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	60,000		60,000		33,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	60,000	31,000	60,000	31,000
Allowance for loan losses:
Beginning balance	40,000	26,000	33,000	21,000
Provisions for loan losses	20,000	2,000	27,000	7,000
Charge-offs	0	0	0	0
Recoveries	0	3,000	0	3,000
Ending balance	60,000	31,000	60,000	31,000
Commercial Real Estate
Ending allowance balance attributable to loans:
Individually evaluated for impairment	441,000		441,000		539,000
Collectively evaluated for impairment	520,000		520,000		730,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	961,000	1,385,000	961,000	1,385,000
Allowance for loan losses:
Beginning balance	826,000	1,271,000	1,269,000	1,051,000
Provisions for loan losses	135,000	114,000	(308,000)	402,000
Charge-offs	0	0	0	(68,000)
Recoveries	0	0	0	0
Ending balance	961,000	1,385,000	961,000	1,385,000
Commercial Business
Ending allowance balance attributable to loans:
Individually evaluated for impairment	914,000		914,000		936,000
Collectively evaluated for impairment	185,000		185,000		224,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	1,099,000	1,186,000	1,099,000	1,186,000
Allowance for loan losses:
Beginning balance	1,154,000	1,020,000	1,160,000	1,251,000
Provisions for loan losses	(60,000)	130,000	(70,000)	199,000
Charge-offs	0	0	0	(305,000)
Recoveries	5,000	36,000	9,000	41,000
Ending balance	1,099,000	1,186,000	1,099,000	1,186,000
Home Equity and Second Mortgage
Ending allowance balance attributable to loans:
Individually evaluated for impairment	29,000		29,000		0
Collectively evaluated for impairment	824,000		824,000		400,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	853,000	331,000	853,000	331,000
Allowance for loan losses:
Beginning balance	840,000	562,000	400,000	606,000
Provisions for loan losses	158,000	3,000	765,000	136,000
Charge-offs	(154,000)	(250,000)	(330,000)	(458,000)
Recoveries	9,000	16,000	18,000	47,000
Ending balance	853,000	331,000	853,000	331,000
Other Consumer
Ending allowance balance attributable to loans:
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	306,000		306,000		399,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	306,000	381,000	306,000	381,000
Allowance for loan losses:
Beginning balance	297,000	406,000	399,000	465,000
Provisions for loan losses	46,000	3,000	2,000	(26,000)
Charge-offs	(90,000)	(73,000)	(236,000)	(211,000)
Recoveries	53,000	45,000	141,000	153,000
Ending balance	$ 306,000	$ 381,000	$ 306,000	$ 381,000