Note 3 - Securities (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Available-for-sale Securities [Table Text Block]

	December 31, 2017
Available for sale:	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
U.S. Government agencies and corporations	$	312,604	$	609	$	5,494	$	307,719
States and political subdivisions		16,853		100		119		16,834
Mortgage-backed securities		602		57		---		659
Corporate debt securities		6,016		188		29		6,175
Total securities available for sale	$	336,075	$	954	$	5,642	$	331,387

	December 31, 2016
Available for sale:	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		F air Value
U.S. Government agencies and corporations	$	291,271	$	492	$	6,165	$	285,598
States and political subdivisions		11,482		211		---		11,693
Mortgage-backed securities		845		85		---		930
Corporate debt securities		6,015		20		137		5,898
Other securities		189		---		26		163
Total securities available for sale	$	309,802	$	808	$	6,328	$	304,282

Investments Classified by Contractual Maturity Date [Table Text Block]

	December 31, 20 1 7
Available for sale:	Amortized Cost		Fair Value
Due in one year or less	$	33,405	$	33,238
Due after one year through five years		192,388		189,005
Due after five years through ten years		72,001		70,509
Due after ten years		38,281		38,635
Total securities available for sale	$	336,075	$	331,387

	December 31, 20 1 7
Held to maturity:	Amortized Cost		Fair Value
Due in one year or less	$	11,906	$	12,088
Due after one year through five years		24,403		25,359
Due after five years through ten years		25,242		25,892
Due after ten years		65,613		66,774
Total securities held to maturity	$	127,164	$	130,113

Held-to-maturity Securities [Table Text Block]

	December 31, 20 1 7
Held to maturity:	Amortized Cost		Gross U nrealized Gains		Gross Unrealized Losses		Fair Value
U.S. Government agencies and corporations	$	3,934	$	167	$	---	$	4,101
States and political subdivisions		122,039		2,929		173		124,795
Mortgage-backed securities		209		21		---		230
Corporate debt securities		982		5		---		987
Total securities held to maturity	$	127,164	$	3,122	$	173	$	130,113

	December 31, 20 1 6
Held to maturity:	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
U.S. Government agencies and corporations	$	3,934	$	201	$	---	$	4,135
States and political subdivisions		129,783		3,579		1,082		132,280
Mortgage-backed securities		265		30		---		295
Corporate debt securities		975		7		---		982
Total securities held to maturity	$	134,957	$	3,817	$	1,082	$	137,692

Schedule of Temporary Impairment Losses, Investments [Table Text Block]

	December 31, 2017
	Less Than 12 Months				12 Months or More
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
U. S. Government agencies and corporations	$	68,380	$	871	$	225,738	$	4,623
State and political subdivisions		18,688		194		2,989		98
Corporate debt securities		---		---		948		29
Total temporarily impaired securities	$	87,068	$	1,065	$	229,675	$	4,750

	December 31, 2016
	Less Than 12 Months				12 Months or More
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
U. S. Government agencies and corporations	$	260,150	$	6,161	$	996	$	4
State and political subdivisions		31,257		934		1,316		148
Corporate debt securities		3,888		137		---		---
Other securities		---		---		163		26
Total temporarily impaired securities	$	295,295	$	7,232	$	2,475	$	178

Schedule of Realized Gain (Loss) on Called Securities [Table Text Block]

	For the year ended December 31, 2017
	Proceeds		Book V alue		Gross G ain		Gross L oss		N et Gain
Available for sale	$	13,620	$	13,614	$	6	$	---	$	6
Held to maturity		8,975		8,971		4		---		4

	For the year ended December 31, 201 6
	Proceeds		Book V alue		Gross Gain		Gross L oss		N et Gain
Available for sale	$	220,520	$	220,334	$	186	$	---	$	186
Held to maturity		16,160		16,114		46		---		46

	For the year ended December 31, 201 5
	Proceeds		Book V alue		Gross Gain		Gross L oss		N et Gain
Available for sale	$	63,775	$	63,742	$	34	$	1	$	33
Held to maturity		7,605		7,605		---		---		---