Note 3 - Investment Securities (Tables)

6 Months Ended

Jun. 30, 2013

Investment Holdings [Abstract]

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

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Fair Value
June 30, 2013:
Securities held to maturity:
Municipal securities	$	104,551,749	$	152,017	$	(5,853,172	)	$	98,850,594
Other securities		650,000		-		-			650,000
	$	105,201,749	$	152,017	$	(5,853,172	)	$	99,500,594
Securities available for sale:
U.S. govt. sponsored agency securities	$	395,513,928	$	238,359	$	(14,836,396	)	$	380,915,891
Residential mortgage-backed and related securities		179,822,160		1,807,687		(3,084,293	)		178,545,554
Municipal securities		36,478,946		1,102,715		(752,811	)		36,828,850
Trust preferred securities		86,200		130,000		-			216,200
Other securities		1,362,730		396,393		(218	)		1,758,905
	$	613,263,964	$	3,675,154	$	(18,673,718	)	$	598,265,400
December 31, 2012:
Securities held to maturity:
Municipal securities	$	71,429,385	$	997,969	$	(71,648	)	$	72,355,706
Other securities		650,000		-		-			650,000
	$	72,079,385	$	997,969	$	(71,648	)	$	73,005,706
Securities available for sale:
U.S. govt. sponsored agency securities	$	336,570,995	$	2,198,655	$	(160,279	)	$	338,609,371
Residential mortgage-backed and related securities		160,035,196		3,736,821		(170,914	)		163,601,103
Municipal securities		24,508,015		1,696,555		(18,834	)		26,185,736
Trust preferred securities		86,200		53,200		-			139,400
Other securities		1,347,113		300,732		(23,469	)		1,624,376
	$	522,547,519	$	7,985,963	$	(373,496	)	$	530,159,986

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, 2013:
Securities held to maturity:
Municipal securities	$	88,263,477	$	(5,853,172	)	$	-	$	-		$	88,263,477	$	(5,853,172	)
Securities available for sale:
U.S. govt. sponsored agency securities	$	351,380,421	$	(14,836,396	)	$	-	$	-		$	351,380,421	$	(14,836,396	)
Residential mortgage-backed and related securities		102,856,893		(3,054,077	)		2,065,109		(30,216	)		104,922,002		(3,084,293	)
Municipal securities		14,212,014		(752,811	)		-		-			14,212,014		(752,811	)
Other securities		-		-			241,345		(218	)		241,345		(218	)
	$	468,449,328	$	(18,643,284	)	$	2,306,454	$	(30,434	)	$	470,755,782	$	(18,673,718	)
December 31, 2012:
Securities held to maturity:
Municipal securities	$	4,282,352	$	(71,648	)	$	-	$	-		$	4,282,352	$	(71,648	)
Securities available for sale:
U.S. govt. sponsored agency securities	$	55,621,718	$	(160,279	)	$	-	$	-		$	55,621,718	$	(160,279	)
Residential mortgage-backed and related securities		29,324,928		(170,914	)		-		-			29,324,928		(170,914	)
Municipal securities		1,039,625		(18,834	)		-		-			1,039,625		(18,834	)
Other securities		-		-			217,500		(23,469	)		217,500		(23,469	)
	$	85,986,271	$	(350,027	)	$	217,500	$	(23,469	)	$	86,203,771	$	(373,496	)

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

	Three Months Ended				Six Months Ended
	June 30, 2013		June 30, 2012		June 30, 2013		June 30, 2012
Proceeds from sales of securities	$	6,167,531	$	19,215,075	$	6,167,531	$	19,215,075
Pre-tax gross gains from sales of securities		16,460		104,600		16,460		104,600

Investments Classified by Contractual Maturity Date [Table Text Block]

	Amortized Cost		Fair Value
Securities held to maturity:
Due in one year or less	$	1,785,269	$	1,784,577
Due after one year through five years		10,214,545		10,126,030
Due after one year through five years		93,201,935		87,589,987
	$	105,201,749	$	99,500,594
Securities available for sale:
Due in one year or less	$	5,334,543	$	5,329,272
Due after one year through five years		33,501,636		33,339,485
Due after five years		393,242,895		379,292,184
	$	432,079,074	$	417,960,941
Residential mortgage-backed and related securities		179,822,160		178,545,554
Other securities		1,362,730		1,758,905
	$	613,263,964	$	598,265,400

	Amortized Cost		Fair Value
Securities held to maturity:
Municipal securities	$	69,862,451	$	65,051,896
Securities available for sale:
U.S. govt. sponsored agency securities		355,831,837		342,070,506
Municipal securities		22,786,922		22,750,101
	$	378,618,759	$	364,820,607