Allowance for Loan Losses (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Ending allowance balance attributable to loans:
Individually evaluated for impairment	$ 1,562,000		$ 1,562,000		$ 1,652,000
Collectively evaluated for impairment	3,342,000		3,342,000		3,084,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	4,904,000	4,591,000	4,904,000	4,591,000
Allowance for loan losses:
Beginning balance	4,835,000	4,432,000	4,736,000	4,182,000
Provisions for loan losses	100,000	350,000	575,000	1,125,000
Charge-offs	(114,000)	(259,000)	(708,000)	(897,000)
Recoveries	83,000	68,000	301,000	181,000
Ending balance	4,904,000	4,591,000	4,904,000	4,591,000
Residential
Ending allowance balance attributable to loans:
Individually evaluated for impairment	95,000		95,000		213,000
Collectively evaluated for impairment	799,000		799,000		709,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	894,000	1,210,000	894,000	1,210,000
Allowance for loan losses:
Beginning balance	905,000	1,173,000	922,000	828,000
Provisions for loan losses	(26,000)	51,000	211,000	697,000
Charge-offs	0	(15,000)	(298,000)	(327,000)
Recoveries	15,000	1,000	59,000	12,000
Ending balance	894,000	1,210,000	894,000	1,210,000
Land
Ending allowance balance attributable to loans:
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	70,000		70,000		71,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	70,000	102,000	70,000	102,000
Allowance for loan losses:
Beginning balance	73,000	102,000	71,000	93,000
Provisions for loan losses	(3,000)	0	1,000	12,000
Charge-offs	0	0	(2,000)	(4,000)
Recoveries	0	0	0	1,000
Ending balance	70,000	102,000	70,000	102,000
Construction
Ending allowance balance attributable to loans:
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	50,000		50,000		0
Acquired with deteriorated credit quality	0		0		0
Ending balance	50,000	60,000	50,000	60,000
Allowance for loan losses:
Beginning balance	60,000	40,000	0	33,000
Provisions for loan losses	(10,000)	20,000	50,000	27,000
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Ending balance	50,000	60,000	50,000	60,000
Commercial Real Estate
Ending allowance balance attributable to loans:
Individually evaluated for impairment	144,000		144,000		275,000
Collectively evaluated for impairment	1,097,000		1,097,000		1,035,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	1,241,000	961,000	1,241,000	961,000
Allowance for loan losses:
Beginning balance	1,291,000	826,000	1,310,000	1,269,000
Provisions for loan losses	(52,000)	135,000	3,000	(308,000)
Charge-offs	(1,000)	0	(89,000)	0
Recoveries	3,000	0	17,000	0
Ending balance	1,241,000	961,000	1,241,000	961,000
Commercial Business
Ending allowance balance attributable to loans:
Individually evaluated for impairment	1,315,000		1,315,000		1,098,000
Collectively evaluated for impairment	159,000		159,000		125,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	1,474,000	1,099,000	1,474,000	1,099,000
Allowance for loan losses:
Beginning balance	1,260,000	1,154,000	1,223,000	1,160,000
Provisions for loan losses	210,000	(60,000)	196,000	(70,000)
Charge-offs	0	0	0	0
Recoveries	4,000	5,000	55,000	9,000
Ending balance	1,474,000	1,099,000	1,474,000	1,099,000
Home Equity and Second Mortgage
Ending allowance balance attributable to loans:
Individually evaluated for impairment	8,000		8,000		66,000
Collectively evaluated for impairment	857,000		857,000		853,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	865,000	853,000	865,000	853,000
Allowance for loan losses:
Beginning balance	894,000	840,000	919,000	400,000
Provisions for loan losses	(13,000)	158,000	(37,000)	765,000
Charge-offs	(24,000)	(154,000)	(59,000)	(330,000)
Recoveries	8,000	9,000	42,000	18,000
Ending balance	865,000	853,000	865,000	853,000
Other Consumer
Ending allowance balance attributable to loans:
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	310,000		310,000		291,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	310,000	306,000	310,000	306,000
Allowance for loan losses:
Beginning balance	352,000	297,000	291,000	399,000
Provisions for loan losses	(6,000)	46,000	151,000	2,000
Charge-offs	(89,000)	(90,000)	(260,000)	(236,000)
Recoveries	53,000	53,000	128,000	141,000
Ending balance	$ 310,000	$ 306,000	$ 310,000	$ 306,000