Note 2 - Investment Securities (Detail) - Gross Unrealized Losses and Fair value of Securities in a Continuous Unrealized Loss Position (USD $)	Mar. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Securities available for sale:
Available for Sale Securities less than 12 months fair value	$ 178,346,143	$ 85,986,271
Available for Sale Securities less than 12 months gross unrealized losses	(898,925)	(350,027)
Available for Sale Securities 12 months or more fair value	235,625	217,500
Available for Sale Securities 12 months or more gross unrealized losses	(5,664)	(23,469)	5,664
Available for Sale Securities fair value	178,581,768	86,203,771
Available for Sale Securities gross unrealized losses	(904,589)	(373,496)
US States and Political Subdivisions Debt Securities [Member]
Securities held to maturity:
Held to Maturity Securities less than 12 months fair value	25,634,890	4,282,352
Held to Maturity Securities less than 12 months gross unrealized losses	(407,348)	(71,648)
Held to Maturity Securities 12 months or more fair value	0	0
Held to Maturity Securities 12 months or more gross unrealized losses	0	0
Held to Maturity Securities fair value	25,634,890	4,282,352
Held to Maturity Securities gross unrealized losses	(407,348)	(71,648)
Securities available for sale:
Available for Sale Securities less than 12 months fair value	2,223,597	1,039,625
Available for Sale Securities less than 12 months gross unrealized losses	(38,738)	(18,834)
Available for Sale Securities 12 months or more fair value	0	0
Available for Sale Securities 12 months or more gross unrealized losses	0	0
Available for Sale Securities fair value	2,223,597	1,039,625
Available for Sale Securities gross unrealized losses	(38,738)	(18,834)
US Government Agencies Debt Securities [Member]
Securities available for sale:
Available for Sale Securities less than 12 months fair value	129,197,592	55,621,718
Available for Sale Securities less than 12 months gross unrealized losses	(418,236)	(160,279)
Available for Sale Securities 12 months or more fair value	0	0
Available for Sale Securities 12 months or more gross unrealized losses	0	0
Available for Sale Securities fair value	129,197,592	55,621,718
Available for Sale Securities gross unrealized losses	(418,236)	(160,279)
Residential Mortgage Backed Securities [Member]
Securities available for sale:
Available for Sale Securities less than 12 months fair value	46,924,954	29,324,928
Available for Sale Securities less than 12 months gross unrealized losses	(441,951)	(170,914)
Available for Sale Securities 12 months or more fair value	0	0
Available for Sale Securities 12 months or more gross unrealized losses	0	0
Available for Sale Securities fair value	46,924,954	29,324,928
Available for Sale Securities gross unrealized losses	(441,951)	(170,914)
Equity Securities, Other [Member]
Securities available for sale:
Available for Sale Securities less than 12 months fair value	0
Available for Sale Securities less than 12 months gross unrealized losses	0
Available for Sale Securities 12 months or more fair value	235,625	217,500
Available for Sale Securities 12 months or more gross unrealized losses	(5,664)	(23,469)
Available for Sale Securities fair value	235,625	217,500
Available for Sale Securities gross unrealized losses	$ (5,664)	$ (23,469)

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