Note 3 - Investment Securities (Tables)

12 Months Ended

Dec. 31, 2013

Investment Holdings [Abstract]

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

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Fair Value
December 31, 2013:
Securities held to maturity:
Municipal securities	$	144,401,895	$	299,789	$	(7,111,579	)	$	137,590,105
Other securities		1,050,000		-		-			1,050,000
	$	145,451,895	$	299,789	$	(7,111,579	)	$	138,640,105
Securities available for sale:
U.S. govt. sponsored agency securities	$	376,574,132	$	41,696	$	(20,142,841	)	$	356,472,987
Residential mortgage-backed and related securities		160,110,199		1,153,409		(3,834,157	)		157,429,451
Municipal securities		35,813,866		923,315		(778,324	)		35,958,857
Other securities		1,372,365		524,798		-			1,897,163
	$	573,870,562	$	2,643,218	$	(24,755,322	)	$	551,758,458
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
December 31, 2013:
Securities held to maturity:
Municipal securities	$	101,983,602	$	(6,711,240	)	$	2,697,375	$	(400,339	)	$	104,680,977	$	(7,111,579	)
Securities available for sale:
U.S. govt. sponsored agency securities	$	333,194,820	$	(19,141,077	)	$	10,978,390	$	(1,001,764	)	$	344,173,210	$	(20,142,841	)
Residential mortgage-backed and related securities		94,723,092		(2,947,770	)		14,117,719		(886,387	)		108,840,811		(3,834,157	)
Municipal securities		13,890,692		(724,939	)		985,687		(53,385	)		14,876,379		(778,324	)
	$	441,808,604	$	(22,813,786	)	$	26,081,796	$	(1,941,536	)	$	467,890,400	$	(24,755,322	)
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]

	2013			2012		2011
Proceeds from sales of securities	$	37,393,047		$	19,215,075	$	54,326,191
Gross gains from sales of securities		523,071			104,600		1,472,528
Gross losses from sales of securities		(90,579	)		-		-

Investments Classified by Contractual Maturity Date [Table Text Block]

	Amortized Cost		Fair Value
Securities held to maturity:
Due in one year or less	$	2,250,529	$	2,250,467
Due after one year through five years		9,340,352		9,309,433
Due after five years		133,861,014		127,080,205
	$	145,451,895	$	138,640,105
Securities available for sale:
Due in one year or less	$	6,416,406	$	6,426,654
Due after one year through five years		46,861,212		46,420,946
Due after five years		359,110,380		339,584,244
	$	412,387,998	$	392,431,844
Residential mortgage-backed and related securities		160,110,199		157,429,451
Other securities		1,372,365		1,897,163
	$	573,870,562	$	551,758,458

	Amortized Cost		Fair Value
Securities held to maturity:
Municipal securities	$	108,408,593	$	102,628,515
Securities available for sale:
U.S. govt. sponsored agency securities		335,565,915		317,138,253
Municipal securities		22,760,530		22,574,232
	$	358,326,445	$	339,712,485