Note 4 - Allowance for Loan Losses (Detail) - Allowance for Loan Losses (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Construction loans:
Beginning balance	$ 3,790,000	$ 3,979,000
Charge-offs	(279,000)	(1,616,000)
Recoveries	163,000	19,000
Provisions	125,000	1,408,000
Ending Balance	3,799,000	3,790,000
Ending balance: individually evaluated for impairment	224,000	208,000
Ending balance: collectively evaluated for impairment	3,575,000	3,582,000
Ending balance	277,259,000	274,937,000
Ending balance: individually evaluated for impairment	14,833,000	15,630,000
Ending balance: collectively evaluated for impairment	262,426,000	259,307,000
Construction Residential [Member]
Construction loans:
Beginning balance	117,000	90,000
Provisions	15,000	27,000
Ending Balance	132,000	117,000
Ending balance: collectively evaluated for impairment	132,000	117,000
Ending balance	5,882,000	5,036,000
Ending balance: collectively evaluated for impairment	5,882,000	5,036,000
Land Acquistion, Development and Commercial [Member]
Construction loans:
Beginning balance	811,000	953,000
Charge-offs		(519,000)
Provisions	34,000	377,000
Ending Balance	845,000	811,000
Ending balance: collectively evaluated for impairment	845,000	811,000
Ending balance	21,934,000	20,198,000
Ending balance: individually evaluated for impairment	3,203,000	3,632,000
Ending balance: collectively evaluated for impairment	18,731,000	16,566,000
Real Estate Residential [Member]
Construction loans:
Beginning balance	725,000	538,000
Charge-offs	(164,000)	(151,000)
Provisions	232,000	338,000
Ending Balance	793,000	725,000
Ending balance: individually evaluated for impairment	137,000	137,000
Ending balance: collectively evaluated for impairment	656,000	588,000
Ending balance	69,757,000	69,691,000
Ending balance: individually evaluated for impairment	635,000	810,000
Ending balance: collectively evaluated for impairment	69,122,000	68,881,000
Real Estate Commercial [Member]
Construction loans:
Beginning balance	1,054,000	1,314,000
Charge-offs	(88,000)	(478,000)
Recoveries	162,000	18,000
Provisions	(66,000)	200,000
Ending Balance	1,062,000	1,054,000
Ending balance: individually evaluated for impairment	87,000	71,000
Ending balance: collectively evaluated for impairment	975,000	983,000
Ending balance	107,892,000	109,302,000
Ending balance: individually evaluated for impairment	9,897,000	10,157,000
Ending balance: collectively evaluated for impairment	97,995,000	99,145,000
Commercial, Industrial and Agricultural [Member]
Construction loans:
Beginning balance	459,000	628,000
Charge-offs	(27,000)	(71,000)
Provisions	(15,000)	(98,000)
Ending Balance	417,000	459,000
Ending balance: collectively evaluated for impairment	417,000	459,000
Ending balance	43,763,000	42,382,000
Ending balance: individually evaluated for impairment	1,098,000	916,000
Ending balance: collectively evaluated for impairment	42,665,000	41,466,000
Equity Lines [Member]
Construction loans:
Beginning balance	386,000	313,000
Charge-offs		(393,000)
Recoveries	1,000
Provisions	(24,000)	466,000
Ending Balance	363,000	386,000
Ending balance: collectively evaluated for impairment	363,000	386,000
Ending balance	19,465,000	20,504,000
Ending balance: individually evaluated for impairment		115,000
Ending balance: collectively evaluated for impairment	19,465,000	20,389,000
Consumer [Member]
Construction loans:
Beginning balance	145,000	143,000
Charge-offs		(4,000)
Recoveries		1,000
Provisions	(11,000)	5,000
Ending Balance	134,000	145,000
Ending balance: collectively evaluated for impairment	134,000	145,000
Ending balance	8,566,000	7,824,000
Ending balance: collectively evaluated for impairment	8,566,000	7,824,000
Unallocated [Member]
Construction loans:
Beginning balance	93,000
Provisions	(40,000)	93,000
Ending Balance	53,000	93,000
Ending balance: collectively evaluated for impairment	$ 53,000	$ 93,000