Note 2 - Investment Securities (Detail) - Amortized Cost and Fair Value of Investment Securities (USD $)	Sep. 30, 2012	Dec. 31, 2011
Securities held to maturity:
Securities held to maturity, other bonds, amortized cost	$ 650,000	$ 200,000
Securities held to maturity, other bonds, gross unrealized gains	0	0
Securities held to maturity, other bonds, gross unrealized losses	0	0
Securities held to maturity, other bonds, fair value	650,000	200,000
Securities available for sale:
Available for Sale Securities, amortized cost	580,796,837	557,333,785
Available for Sale Securities, gross unrealized gains	9,988,223	7,809,612
Available for Sale Securities, gross unrealized losses	(83,611)	(114,106)
Available for Sale Securities, fair value	590,701,449	565,029,291
US Government Agencies Debt Securities [Member]
Securities available for sale:
Available for Sale Securities, amortized cost	340,538,125	426,581,913
Available for Sale Securities, gross unrealized gains	2,712,996	2,428,994
Available for Sale Securities, gross unrealized losses	(7,499)	(55,687)
Available for Sale Securities, fair value	343,243,622	428,955,220
Residential Mortgage Backed Securities [Member]
Securities available for sale:
Available for Sale Securities, amortized cost	151,264,044	105,373,614
Available for Sale Securities, gross unrealized gains	4,450,612	3,488,350
Available for Sale Securities, gross unrealized losses	(24,081)	(8,215)
Available for Sale Securities, fair value	155,690,575	108,853,749
US States and Political Subdivisions Debt Securities [Member]
Securities available for sale:
Available for Sale Securities, amortized cost	87,579,277	23,937,118
Available for Sale Securities, gross unrealized gains	2,478,687	1,752,246
Available for Sale Securities, gross unrealized losses	(26,333)	0
Available for Sale Securities, fair value	90,031,631	25,689,364
Trust preferred securities [Member]
Securities available for sale:
Available for Sale Securities, amortized cost	86,200	86,200
Available for Sale Securities, gross unrealized gains	44,200	0
Available for Sale Securities, gross unrealized losses	0	(5,400)
Available for Sale Securities, fair value	130,400	80,800
Securities (Assets) [Member]
Securities available for sale:
Available for Sale Securities, amortized cost	1,329,191	1,354,940
Available for Sale Securities, gross unrealized gains	301,728	140,022
Available for Sale Securities, gross unrealized losses	(25,698)	(44,804)
Available for Sale Securities, fair value	$ 1,605,221	$ 1,450,158

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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