Note 2 - Investment Securities (Tables)

6 Months Ended

Jun. 30, 2014

Investment Holdings [Abstract]

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

			Gross		Gross
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		(Losses)			Value
June 30, 2014
Securities held to maturity:
Municipal securities	$	165,737,372	$	1,492,583	$	(2,609,628	)	$	164,620,327
Other securities		1,050,000		-		-			1,050,000
	$	166,787,372	$	1,492,583	$	(2,609,628	)	$	165,670,327
Securities available for sale:
U.S. govt. sponsored agency securities	$	334,083,927	$	109,470	$	(8,572,941	)	$	325,620,456
Residential mortgage-backed and related securities		152,965,071		2,200,301		(1,270,158	)		153,895,214
Municipal securities		32,871,334		1,156,141		(170,004	)		33,857,471
Other securities		1,401,827		560,129		-			1,961,956
	$	521,322,159	$	4,026,041	$	(10,013,103	)	$	515,335,097
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

Schedule of Unrealized Loss on Investments [Table Text Block]

	Less than 12 Months					12 Months or More					Total
			Gross					Gross					Gross
	Fair		Unrealized			Fair		Unrealized			Fair		Unrealized
	Value		Losses			Value		Losses			Value		Losses
June 30, 2014:
Securities held to maturity:
Municipal securities	$	37,351,435	$	(982,726	)	$	47,726,709	$	(1,626,902	)	$	85,078,144	$	(2,609,628	)
Securities available for sale:
U.S. govt. sponsored agency securities	$	284,171,721	$	(8,502,103	)	$	13,725,024	$	(70,838	)	$	297,896,745	$	(8,572,941	)
Residential mortgage-backed and related securities		8,124,317		(95,270	)		55,800,561		(1,174,888	)		63,924,878		(1,270,158	)
Municipal securities		8,765,260		(131,548	)		2,184,122		(38,456	)		10,949,382		(170,004	)
	$	301,061,298	$	(8,728,921	)	$	71,709,707	$	(1,284,182	)	$	372,771,005	$	(10,013,103	)
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	)

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

	Three Months Ended				Six Months Ended
	June 30, 2014		June 30, 2013		June 30, 2014		June 30, 2013
Proceeds from sales of securities	$	18,856,953	$	6,167,531	$	25,877,578	$	6,167,531
Pre-tax gross gains from sales of securities		571		16,460		21,196		16,460

Investments Classified by Contractual Maturity Date [Table Text Block]

	Amortized Cost		Fair Value
Securities held to maturity:
Due in one year or less	$	2,927,386	$	2,929,942
Due after one year through five years		10,861,031		10,874,917
Due after five years		152,998,955		151,865,468
	$	166,787,372	$	165,670,327
Securities available for sale:
Due in one year or less	$	4,485,092	$	4,498,204
Due after one year through five years		48,898,104		48,717,600
Due after five years		313,572,065		306,262,123
	$	366,955,261	$	359,477,927
Residential mortgage-backed and related securities		152,965,071		153,895,214
Other securities		1,401,827		1,961,956
	$	521,322,159	$	515,335,097

	Amortized Cost		Fair Value
Securities held to maturity:
Municipal securities	$	102,919,232	$	102,260,651
Securities available for sale:
U.S. govt. sponsored agency securities		271,663,942		264,421,214
Municipal securities		20,829,274		21,268,094
	$	292,493,216	$	285,689,308