Note 3 - Securities (Tables)

3 Months Ended

Mar. 31, 2015

Investments, Debt and Equity Securities [Abstract]

Available-for-sale Securities [Table Text Block]

			Gross		Gross
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
March 31, 2015
U.S. Government agency debt obligations	$	179,076,000	$	2,201,000	$	(1,363,000	)	$	179,914,000
Mortgage-backed securities		86,295,000		1,253,000		(266,000	)		87,282,000
Municipal general obligation bonds		133,009,000		1,501,000		(248,000	)		134,262,000
Municipal revenue bonds		10,173,000		116,000		(2,000	)		10,287,000
Other investments		1,932,000		16,000		0			1,948,000
	$	410,485,000	$	5,087,000	$	(1,879,000	)	$	413,693,000
December 31, 2014
U.S. Government agency debt obligations	$	194,894,000	$	1,612,000	$	(3,038,000	)	$	193,468,000
Mortgage-backed securities		92,656,000		1,123,000		(218,000	)		93,561,000
Municipal general obligation bonds		132,347,000		1,042,000		(307,000	)		133,082,000
Municipal revenue bonds		10,769,000		117,000		(13,000	)		10,873,000
Other investments		1,925,000		3,000		0			1,928,000
	$	432,591,000	$	3,897,000	$	(3,576,000	)	$	432,912,000

Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Table Text Block]

	Less than 12 Months				12 Months or More				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Loss		Value		Loss		Value		Loss
March 31, 2015
U.S. Government agency debt obligations	$	19,508,000	$	32,000	$	69,136,000	$	1,331,000	$	88,644,000	$	1,363,000
Mortgage-backed securities		26,839,000		266,000		0		0		26,839,000		266,000
Municipal general obligation bonds		14,427,000		248,000		0		0		14,427,000		248,000
Municipal revenue bonds		1,885,000		2,000		0		0		1,885,000		2,000
Other investments		0		0		0		0		0		0
	$	62,659,000	$	548,000	$	69,136,000	$	1,331,000	$	131,795,000	$	1,879,000

	Less than 12 Months				12 Months or More				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Loss		Value		Loss		Value		Loss
December 31, 2014
U.S. Government agency debt obligations	$	81,891,000	$	202,000	$	74,120,000	$	2,836,000	$	156,011,000	$	3,038,000
Mortgage-backed securities		49,940,000		218,000		0		0		49,940,000		218,000
Municipal general obligation bonds		54,104,000		307,000		0		0		54,104,000		307,000
Municipal revenue bonds		4,644,000		13,000		0		0		4,644,000		13,000
Other investments		0		0		0		0		0		0
	$	190,579,000	$	740,000	$	74,120,000	$	2,836,000	$	264,699,000	$	3,576,000

Investments Classified by Contractual Maturity Date [Table Text Block]

	Weighted
	Average			Amortized		Fair
	Yield			Cost		Value
Due in 2015		0.71	%	$	23,762,000	$	23,781,000
Due in 2016 through 2020		1.44			145,330,000		145,610,000
Due in 2021 through 2025		3.49			67,554,000		68,163,000
Due in 2026 and beyond		3.58			85,612,000		86,909,000
Mortgage‑backed securities		1.78			86,295,000		87,282,000
Other investments		2.50			1,932,000		1,948,000
		2.19	%	$	410,485,000	$	413,693,000