Note 3 - Investment Securities (Tables)

12 Months Ended

Dec. 31, 2015

Note 3 - Investment Securities (Tables) [Line Items]

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

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Fair Value
December 31, 2015:
Securities held to maturity:
Municipal securities	$	252,624,159	$	3,190,558	$	(1,173,432	)	$	254,641,285
Other securities		1,050,000		-		-			1,050,000
	$	253,674,159	$	3,190,558	$	(1,173,432	)	$	255,691,285
Securities available for sale:
U.S. govt. sponsored agency securities	$	216,281,416	$	104,524	$	(2,848,561	)	$	213,537,379
Residential mortgage-backed and related securities		81,442,479		511,095		(1,283,439	)		80,670,135
Municipal securities		26,764,981		872,985		(59,378	)		27,578,588
Other securities		1,108,124		540,919		(163	)		1,648,880
	$	325,597,000	$	2,029,523	$	(4,191,541	)	$	323,434,982
December 31, 2014:
Securities held to maturity:
Municipal securities	$	198,829,574	$	2,420,298	$	(1,186,076	)	$	200,063,796
Other securities		1,050,000		-		-			1,050,000
	$	199,879,574	$	2,420,298	$	(1,186,076	)	$	201,113,796
Securities available for sale:
U.S. govt. sponsored agency securities	$	312,959,760	$	173,685	$	(5,263,873	)	$	307,869,572
Residential mortgage-backed and related securities		110,455,925		1,508,331		(541,032	)		111,423,224
Municipal securities		29,408,740		1,053,713		(62,472	)		30,399,981
Other securities		1,342,554		625,145		(846	)		1,966,853
	$	454,166,979	$	3,360,874	$	(5,868,223	)	$	451,659,630

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, 2015:
Securities held to maturity:
Municipal securities	$	14,803,408	$	(294,438	)	$	19,927,581	$	(878,994	)	$	34,730,989	$	(1,173,432	)
Securities available for sale:
U.S. govt. sponsored agency securities	$	112,900,327	$	(1,397,591	)	$	64,476,661	$	(1,450,970	)	$	177,376,988	$	(2,848,561	)
Residential mortgage-backed and related securities		40,356,921		(730,466	)		19,836,637		(552,973	)		60,193,558		(1,283,439	)
Municipal securities		2,220,800		(31,807	)		848,329		(27,571	)		3,069,129		(59,378	)
Other securities		411		(163	)		-		-			411		(163	)
	$	155,478,459	$	(2,160,027	)	$	85,161,627	$	(2,031,514	)	$	240,640,086	$	(4,191,541	)
December 31, 2014:
Securities held to maturity:
Municipal securities	$	20,419,052	$	(587,992	)	$	38,779,545	$	(598,084	)	$	59,198,597	$	(1,186,076	)
Securities available for sale:
U.S. govt. sponsored agency securities	$	23,970,085	$	(102,695	)	$	255,743,056	$	(5,161,178	)	$	279,713,141	$	(5,263,873	)
Residential mortgage-backed and related securities		10,710,671		(10,139	)		37,570,774		(530,893	)		48,281,445		(541,032	)
Municipal securities		920,935		(1,773	)		4,425,337		(60,699	)		5,346,272		(62,472	)
Other securities		243,004		(846	)		-		-			243,004		(846	)
	$	35,844,695	$	(115,453	)	$	297,739,167	$	(5,752,770	)	$	333,583,862	$	(5,868,223	)

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

	2015			2014			2013
Proceeds from sales of securities	$	81,410,368		$	78,476,422		$	37,393,047
Gross gains from sales of securities		1,045,444			517,116			523,071
Gross losses from sales of securities		(246,461	)		(424,753	)		(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	$	3,801,378	$	3,803,101
Due after one year through five years		20,215,332		20,344,971
Due after five years		229,657,449		231,543,213
	$	253,674,159	$	255,691,285
Securities available for sale:
Due in one year or less	$	1,858,965	$	1,858,071
Due after one year through five years		120,846,468		119,986,551
Due after five years		120,340,964		119,271,345
	$	243,046,397	$	241,115,967
Residential mortgage-backed and related securities		81,442,479		80,670,135
Other securities		1,108,124		1,648,880
	$	325,597,000	$	323,434,982

	Amortized Cost		Fair Value
Securities held to maturity:
Municipal securities	$	139,103,302	$	140,444,117
Securities available for sale:
U.S. govt. sponsored agency securities		127,935,745		125,936,777
Municipal securities		16,751,793		17,127,904
	$	144,687,538	$	143,064,681

Schedule of Debt [Table Text Block]

	2015		2014
Wholesale structured repurchase agreements	$	110,000,000	$	130,000,000
Term note		-		17,625,000
Series A subordinated notes		-		2,657,492
	$	110,000,000	$	150,282,492

Bonds [Member]

Note 3 - Investment Securities (Tables) [Line Items]

Schedule of Debt [Table Text Block]

December 31, 2015:
U.S. State:	Number of Issuers		Amortized Cost		Fair Value		Average Exposure Per Issuer (Fair Value)
Iowa		15	$	19,974,939	$	20,247,108	$	1,349,807
Illinois		9		10,928,700		11,264,348		1,251,594
North Dakota		5		10,890,000		11,050,235		2,210,047
Missouri		12		7,924,800		7,986,856		665,571
Other		41		16,965,393		17,229,485		420,231
Total general obligation bonds		82	$	66,683,832	$	67,778,032	$	826,561

December 31, 2014:
U.S. State:	Number of Issuers		Amortized Cost		Fair Value		Average Exposure Per Issuer (Fair Value)
Illinois		10	$	22,447,799	$	22,784,638	$	2,278,464
Iowa		14		20,156,969		20,446,655		1,460,475
Missouri		11		8,424,928		8,426,047		766,004
Other		42		16,838,719		17,110,831		407,401
Total general obligation bonds		77	$	67,868,415	$	68,768,171	$	893,093

December 31, 2015:
U.S. State:	Number of Issuers		Amortized Cost		Fair Value		Average Exposure Per Issuer (Fair Value)
Missouri		41	$	78,593,590	$	79,015,378	$	1,927,204
Iowa		26		70,773,660		71,659,410		2,756,131
Indiana		17		40,018,381		40,210,320		2,365,313
Kansas		3		11,748,679		11,821,055		3,940,352
Other		5		11,570,998		11,735,678		2,347,136
Total revenue bonds		92	$	212,705,308	$	214,441,841	$	2,330,890

December 31, 2014:
U.S. State:	Number of Issuers		Amortized Cost		Fair Value		Average Exposure Per Issuer (Fair Value)
Missouri		30	$	62,358,276	$	62,584,516	$	2,086,151
Iowa		20		59,417,246		60,402,941		3,020,147
Indiana		8		17,991,200		17,925,721		2,240,715
Kansas		2		12,307,866		12,332,528		6,166,264
Other		4		8,295,311		8,449,900		2,112,475
Total revenue bonds		64	$	160,369,899	$	161,695,606	$	2,526,494