Note 2 - Investment Securities (Tables)

6 Months Ended

Jun. 30, 2012

Unrealized Gain (Loss) on Investments [Table Text Block]

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Fair Value
June 30, 2012:
Securities held to maturity:
Other bonds	$	700,000	$	-	$	-		$	700,000
Securities available for sale:
U.S. govt. sponsored agency securities	$	387,413,822	$	2,377,067	$	(191,137	)	$	389,599,752
Residential mortgage-backed and related securities		162,415,855		3,523,570		(112,224	)		165,827,201
Municipal securities		79,658,038		1,834,640		(420,770	)		81,071,908
Trust preferred securities		86,200		15,800		-			102,000
Other securities		1,319,560		257,847		(40,432	)		1,536,975
	$	630,893,475	$	8,008,924	$	(764,563	)	$	638,137,836
December 31, 2011:
Securities held to maturity:
Other bonds	$	200,000	$	-	$	-		$	200,000
Securities available for sale:
U.S. govt. sponsored agency securities	$	426,581,913	$	2,428,994	$	(55,687	)	$	428,955,220
Residential mortgage-backed and related securities		105,373,614		3,488,350		(8,215	)		108,853,749
Municipal securities		23,937,118		1,752,246		-			25,689,364
Trust preferred securities		86,200		-		(5,400	)		80,800
Other securities		1,354,940		140,022		(44,804	)		1,450,158
	$	557,333,785	$	7,809,612	$	(114,106	)	$	565,029,291

Schedule of Unrealized Loss on Investments [Table Text Block]

	Less than 12 Months					12 Months or More					Total
	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
June 30, 2012:
Securities available for sale:
U.S. govt. sponsored agency securities	$	46,609,893	$	(191,137	)	$	-	$	-		$	46,609,893	$	(191,137	)
Residential mortgage-backed and related securities		26,844,026		(112,224	)		-		-			26,844,026		(112,224	)
Municipal securities		21,831,460		(420,770	)		-		-			21,831,460		(420,770	)
Other securities		200,000		(40,432	)		-		-			200,000		(40,432	)
	$	95,485,379	$	(764,563	)	$	-	$	-		$	95,485,379	$	(764,563	)
December 31, 2011:
Securities available for sale:
U.S. govt. sponsored agency securities	$	59,979,620	$	(55,687	)	$	-	$	-		$	59,979,620	$	(55,687	)
Residential mortgage-backed and related securities		4,906,398		(8,215	)		-		-			4,906,398		(8,215	)
Trust preferred securities		-		-			80,800		(5,400	)		80,800		(5,400	)
Other securities		251,957		(44,332	)		2,778		(472	)		254,735		(44,804	)
	$	65,137,975	$	(108,234	)	$	83,578	$	(5,872	)	$	65,221,553	$	(114,106	)

Realized Gain (Loss) on Investments [Table Text Block]

	Three Months Ended				Six Months Ended
	June 30, 2012		June 30, 2011		June 30, 2012		June 30, 2011
Proceeds from sales of securities	$	19,215,075	$	8,331,005	$	19,215,075	$	45,725,084
Pre-tax gross gains from sales of securities		104,600		148,602		104,600		1,028,914

Investments Classified by Contractual Maturity Date [Table Text Block]

	Amortized Cost		Fair Value
Securities held to maturity:
Due in one year or less	$	50,000	$	50,000
Due after one year through five years		100,000		100,000
Due after five years		550,000		550,000
	$	700,000	$	700,000
Securities available for sale:
Due in one year or less	$	2,554,433	$	2,569,961
Due after one year through five years		57,416,808		57,848,858
Due after five years		407,186,819		410,354,841
	$	467,158,060	$	470,773,660
Residential mortgage-backed and related securities		162,415,855		165,827,201
Other securities		1,319,560		1,536,975
	$	630,893,475	$	638,137,836