Allowance for Loan Losses (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Ending allowance balance attributable to loans:
Individually evaluated for impairment	$ 1,347,000		$ 1,347,000		$ 1,652,000
Collectively evaluated for impairment	3,488,000		3,488,000		3,084,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	4,835,000	4,432,000	4,835,000	4,432,000
Allowance for loan losses:
Beginning balance	4,792,000	4,228,000	4,736,000	4,182,000
Provisions for loan losses	225,000	300,000	475,000	775,000
Charge-offs	(276,000)	(152,000)	(594,000)	(638,000)
Recoveries	94,000	56,000	218,000	113,000
Ending balance	4,835,000	4,432,000	4,835,000	4,432,000
Residential
Ending allowance balance attributable to loans:
Individually evaluated for impairment	93,000		93,000		213,000
Collectively evaluated for impairment	812,000		812,000		709,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	905,000	1,173,000	905,000	1,173,000
Allowance for loan losses:
Beginning balance	940,000	1,060,000	922,000	828,000
Provisions for loan losses	24,000	147,000	236,000	646,000
Charge-offs	(99,000)	(35,000)	(297,000)	(312,000)
Recoveries	40,000	1,000	44,000	11,000
Ending balance	905,000	1,173,000	905,000	1,173,000
Land
Ending allowance balance attributable to loans:
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	73,000		73,000		71,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	73,000	102,000	73,000	102,000
Allowance for loan losses:
Beginning balance	69,000	99,000	71,000	93,000
Provisions for loan losses	6,000	3,000	4,000	12,000
Charge-offs	(2,000)	0	(2,000)	(4,000)
Recoveries	0	0	0	1,000
Ending balance	73,000	102,000	73,000	102,000
Construction
Ending allowance balance attributable to loans:
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	60,000		60,000		0
Acquired with deteriorated credit quality	0		0		0
Ending balance	60,000	40,000	60,000	40,000
Allowance for loan losses:
Beginning balance	50,000	35,000	0	33,000
Provisions for loan losses	10,000	5,000	60,000	7,000
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Ending balance	60,000	40,000	60,000	40,000
Commercial Real Estate
Ending allowance balance attributable to loans:
Individually evaluated for impairment	164,000		164,000		275,000
Collectively evaluated for impairment	1,127,000		1,127,000		1,035,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	1,291,000	826,000	1,291,000	826,000
Allowance for loan losses:
Beginning balance	1,291,000	924,000	1,310,000	1,269,000
Provisions for loan losses	89,000	(98,000)	56,000	(443,000)
Charge-offs	(89,000)	0	(89,000)	0
Recoveries	0	0	14,000	0
Ending balance	1,291,000	826,000	1,291,000	826,000
Commercial Business
Ending allowance balance attributable to loans:
Individually evaluated for impairment	1,065,000		1,065,000		1,098,000
Collectively evaluated for impairment	195,000		195,000		125,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	1,260,000	1,154,000	1,260,000	1,154,000
Allowance for loan losses:
Beginning balance	1,226,000	1,175,000	1,223,000	1,160,000
Provisions for loan losses	33,000	(22,000)	(13,000)	(10,000)
Charge-offs	0	0	0	0
Recoveries	1,000	1,000	50,000	4,000
Ending balance	1,260,000	1,154,000	1,260,000	1,154,000
Home Equity and Second Mortgage
Ending allowance balance attributable to loans:
Individually evaluated for impairment	25,000		25,000		66,000
Collectively evaluated for impairment	869,000		869,000		853,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	894,000	840,000	894,000	840,000
Allowance for loan losses:
Beginning balance	886,000	651,000	919,000	400,000
Provisions for loan losses	9,000	246,000	(24,000)	607,000
Charge-offs	(21,000)	(62,000)	(35,000)	(176,000)
Recoveries	20,000	5,000	34,000	9,000
Ending balance	894,000	840,000	894,000	840,000
Other Consumer
Ending allowance balance attributable to loans:
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	352,000		352,000		291,000
Acquired with deteriorated credit quality	0		0		0
Ending balance	352,000	297,000	352,000	297,000
Allowance for loan losses:
Beginning balance	330,000	284,000	291,000	399,000
Provisions for loan losses	54,000	19,000	156,000	(44,000)
Charge-offs	(65,000)	(55,000)	(171,000)	(146,000)
Recoveries	33,000	49,000	76,000	88,000
Ending balance	$ 352,000	$ 297,000	$ 352,000	$ 297,000