Note 4 - Securities (Tables)

12 Months Ended

Dec. 31, 2015

Investments, Debt and Equity Securities [Abstract]

Schedule of Available-for-sale Securities Reconciliation [Table Text Block]

(in thousands)	Amortized		Unrealized
December 31, 2015	cost		Gains		Losses		Fair value
U.S. Treasury and other U.S. government obligations	$	79,999	$	1	$	-	$	80,000
Government sponsored enterprise obligations		251,190		1,468		765		251,893
Mortgage-backed securities - government agencies		170,139		1,143		1,654		169,628
Obligations of states and political subdivisions		62,410		1,342		50		63,702
Corporate equity securities		653		-		-		653
Total securities available-for-sale	$	564,391	$	3,954	$	2,469	$	565,876

(in thousands)	Amortized		Unrealized
December 31, 2014	cost		Gains		Losses		Fair value
U.S. Treasury and other U.S. government obligations	$	70,000	$	-	$	-	$	70,000
Government sponsored enterprise obligations		203,531		2,017		562		204,986
Mortgage-backed securities - government agencies		173,573		2,042		1,345		174,270
Obligations of states and political subdivisions		61,416		1,560		142		62,834
Corporate equity securities		756		210		-		966
Total securities available-for-sale	$	509,276	$	5,829	$	2,049	$	513,056

Investments Classified by Contractual Maturity Date [Table Text Block]

(in thousands)
Securities available-for-sale		Amortized cost		Fair value
Due within 1 year	$	121,784	$	121,877
Due after 1 but within 5 years		141,714		142,875
Due after 5 but within 10 years		21,610		21,810
Due after 10 years		108,491		109,033
Corporate equity securities		653		653
Mortgage-backed securities - government agencies		170,139		169,628
Total securities available for sale	$	564,391	$	565,876

Schedule of Unrealized Loss on Investments [Table Text Block]

(in thousands)	Less than 12 months				12 months or more				Total
December 31, 2015	Fair value		Unrealized losses		Fair value		Unrealized  losses		Fair  value		Unrealized losses
Government sponsored enterprise obligations	$	102,098	$	500	$	8,469	$	265	$	110,567	$	765
Mortgage-backed securities - government agencies		49,774		662		29,936		992		79,710		1,654
Obligations of states and political subdivisions		13,225		31		1,955		19		15,180		50
Total temporarily impaired securities	$	165,097	$	1,193	$	40,360	$	1,276	$	205,457	$	2,469
December 31, 2014
Government sponsored enterprise obligations	$	36,979	$	30	$	26,848	$	532	$	63,827	$	562
Mortgage-backed securities - government agencies		4,038		77		49,325		1,268		53,363		1,345
Obligations of states and political subdivisions		12,655		67		6,297		75		18,952		142
Total temporarily impaired securities	$	53,672	$	174	$	82,470	$	1,875	$	136,142	$	2,049