Note 2 - Investment Securities (Tables)

3 Months Ended

Mar. 31, 2018

Notes Tables

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

			Gross		Gross
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		(Losses)			Value
March 31, 2018:
Securities HTM:
Municipal securities	$	377,534,337	$	2,244,218	$	(5,024,697	)	$	374,753,858
Other securities		1,050,000		-		(11,175	)		1,038,825
	$	378,584,337	$	2,244,218	$	(5,035,872	)	$	375,792,683
Securities AFS:
U.S. govt. sponsored agency securities	$	37,591,155	$	21,236	$	(744,881	)	$	36,867,510
Residential mortgage-backed and related securities		162,453,605		60,222		(5,224,784	)		157,289,043
Municipal securities		61,862,665		238,583		(899,444	)		61,201,804
Other securities		4,254,716		31,867		-			4,286,583
	$	266,162,141	$	351,908	$	(6,869,109	)	$	259,644,940
December 31, 2017:
Securities HTM:
Municipal securities	$	378,424,205	$	2,763,718	$	(2,488,119	)	$	378,699,804
Other securities		1,050,000		-		-			1,050,000
	$	379,474,205	$	2,763,718	$	(2,488,119	)	$	379,749,804
Securities AFS:
U.S. govt. sponsored agency securities	$	38,409,157	$	37,344	$	(349,967	)	$	38,096,534
Residential mortgage-backed and related securities		165,459,470		155,363		(2,313,529	)		163,301,304
Municipal securities		66,176,364		660,232		(211,100	)		66,625,496
Other securities		4,014,004		896,384		(25,815	)		4,884,573
	$	274,058,995	$	1,749,323	$	(2,900,411	)	$	272,907,907

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
March 31, 2018:
Securities HTM:
Municipal securities	$	69,404,232	$	(2,881,032	)	$	59,545,239	$	(2,143,665	)	$	128,949,471	$	(5,024,697	)
Other securities		1,038,825		(11,175	)		-		-			1,038,825		(11,175	)
	$	70,443,057	$	(2,892,207	)	$	59,545,239	$	(2,143,665	)	$	129,988,296	$	(5,035,872	)
Securities AFS:
U.S. govt. sponsored agency securities	$	29,643,497	$	(589,515	)	$	3,634,609	$	(155,365	)	$	33,278,106	$	(744,880	)
Residential mortgage-backed and related securities		94,102,512		(2,858,578	)		55,394,159		(2,366,206	)		149,496,671		(5,224,784	)
Municipal securities		36,845,821		(659,492	)		8,217,318		(239,952	)		45,063,139		(899,444	)
	$	160,591,830	$	(4,107,585	)	$	67,246,086	$	(2,761,523	)	$	227,837,916	$	(6,869,108	)
December 31, 2017:
Securities HTM:
Municipal securities	$	23,750,826	$	(354,460	)	$	72,611,780	$	(2,133,659	)	$	96,362,606	$	(2,488,119	)
Securities AFS:
U.S. govt. sponsored agency securities	$	28,576,258	$	(200,022	)	$	3,640,477	$	(149,945	)	$	32,216,735	$	(349,967	)
Residential mortgage-backed and related securities		88,927,779		(871,855	)		57,931,731		(1,441,674	)		146,859,510		(2,313,529	)
Municipal securities		10,229,337		(41,151	)		9,997,433		(169,949	)		20,226,770		(211,100	)
Other securities		923,535		(25,815	)		-		-			923,535		(25,815	)
	$	128,656,909	$	(1,138,843	)	$	71,569,641	$	(1,761,568	)	$	200,226,550	$	(2,900,411	)

Investments Classified by Contractual Maturity Date [Table Text Block]

	Amortized Cost		Fair Value
Securities HTM:
Due in one year or less	$	3,344,356	$	3,345,990
Due after one year through five years		25,163,524		25,191,668
Due after five years		350,076,457		347,255,025
	$	378,584,337	$	375,792,683
Securities AFS:
Due in one year or less	$	3,368,633	$	3,381,748
Due after one year through five years		23,949,100		23,738,028
Due after five years		76,390,803		75,236,121
		103,708,536		102,355,897
Residential mortgage-backed and related securities		162,453,605		157,289,043
	$	266,162,141	$	259,644,940

	Amortized Cost		Fair Value
Securities HTM:
Municipal securities	$	209,306,946	$	207,262,788
Securities AFS:
U.S. govt. sponsored agency securities		5,048,812		4,947,644
Municipal securities		54,016,828		53,258,850
	$	59,065,640	$	58,206,494

Schedule of Investment in Bond Securities [Table Text Block]

March 31, 2018:
U.S. State:	Number of Issuers		Amortized Cost		Fair Value		Average Exposure Per Issuer (Fair Value)
North Dakota		7	$	21,627,097	$	20,756,566	$	2,965,224
Illinois		20		18,532,776		18,513,766		925,688
Iowa		16		13,878,991		13,830,003		864,375
Texas		17		10,763,333		10,554,430		620,849
Missouri		17		8,314,872		8,323,476		489,616
Ohio		8		7,378,887		7,296,859		912,107
Other		43		22,261,263		22,068,390		513,218
Total general obligation bonds		128	$	102,757,219	$	101,343,490	$	791,746

December 31, 2017:
U.S. State:	Number of Issuers		Amortized Cost		Fair Value		Average Exposure Per Issuer (Fair Value)
North Dakota		7	$	21,626,574	$	21,724,197	$	3,103,457
Illinois		20		19,328,700		19,514,024		975,701
Iowa		16		13,881,689		13,969,512		873,095
Texas		17		11,253,775		11,308,848		665,226
Missouri		17		9,243,355		9,308,287		547,546
Ohio		9		8,002,705		7,938,028		882,003
Other		45		24,000,278		24,215,119		538,114
Total general obligation bonds		131	$	107,337,076	$	107,978,015	$	824,260

March 31, 2018:
U.S. State:	Number of Issuers		Amortized Cost		Fair Value		Average Exposure Per Issuer (Fair Value)
Missouri		58	$	108,311,804	$	108,445,780	$	1,869,755
Iowa		29		68,370,374		68,236,038		2,352,967
Ohio		10		55,757,914		55,699,375		5,569,938
Indiana		26		49,258,364		48,833,113		1,878,197
Illinois		2		17,205,951		17,373,994		8,686,997
Kansas		6		12,651,338		12,172,961		2,028,827
North Dakota		5		11,220,278		10,644,441		2,128,888
Other		12		13,863,760		13,206,470		1,100,539
Total revenue bonds		148	$	336,639,783	$	334,612,172	$	2,260,893

December 31, 2017:
U.S. State:	Number of Issuers		Amortized Cost		Fair Value		Average Exposure Per Issuer (Fair Value)
Missouri		56	$	106,259,015	$	106,232,837	$	1,897,015
Iowa		29		68,724,899		69,079,470		2,382,051
Ohio		10		55,766,091		55,820,203		5,582,020
Indiana		26		51,171,818		50,861,336		1,956,205
Illinois		2		17,211,441		17,408,544		8,704,272
Kansas		6		12,873,329		12,877,087		2,146,181
North Dakota		5		11,451,560		11,351,676		2,270,335
Other		11		13,805,340		13,716,132		1,246,921
Total revenue bonds		145	$	337,263,493	$	337,347,285	$	2,326,533