Note 3 - Investment Securities Available-for-sale (Tables)

3 Months Ended

Mar. 31, 2017

Notes Tables

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

			Gross		Gross		Estimated
March 31, 2017	Amortized		Unrealized		Unrealized		Fair
(dollars in thousands)	Cost		Gains		Losses		Value
U. S. agency securities	$	149,160	$	315	$	1,567	$	147,908
Residential mortgage backed securities		299,757		478		3,310		296,925
Municipal bonds		43,255		1,369		15		44,609
Corporate bonds		10,013		134		-		10,147
Other equity investments		218		-		-		218
	$	502,403	$	2,296	$	4,892	$	499,807

			Gross		Gross		Estimated
December 31, 2016	Amortized		Unrealized		Unrealized		Fair
(dollars in thousands)	Cost		Gains		Losses		Value
U. S. agency securities	$	107,425	$	519	$	1,802	$	106,142
Residential mortgage backed securities		329,606		324		3,691		326,239
Municipal bonds		94,607		1,723		400		95,930
Corporate bonds		9,508		82		11		9,579
Other equity investments		218		-		-		218
	$	541,364	$	2,648	$	5,904	$	538,108

			Gross		Gross		Estimated
March 31, 2016	Amortized		Unrealized		Unrealized		Fair
(dollars in thousands)	Cost		Gains		Losses		Value
U. S. agency securities	$	54,948	$	774	$	100	$	55,622
Residential mortgage backed securities		305,351		2,073		612		306,812
Municipal bonds		104,840		5,069		-		109,909
Corporate bonds		15,085		-		147		14,938
Other equity investments		310		18		-		328
	$	480,534	$	7,934	$	859	$	487,609

Schedule of Unrealized Loss on Investments [Table Text Block]

			Less than				12 Months
			12 Months				or Greater				Total
			Estimated				Estimated				Estimated
March 31, 2017	Number of		Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
(dollars in thousands)	Securities		Value		Losses		Value		Losses		Value		Losses
U. S. agency securities		30	$	98,493	$	1,535	$	3,661	$	32	$	102,154	$	1,567
Residential mortgage backed securities		114		229,743		2,730		20,711		580		250,454		3,310
Municipal bonds		4		3,487		15		-		-		3,487		15
		148	$	331,723	$	4,280	$	24,372	$	612	$	356,095	$	4,892

			Less than				12 Months
			12 Months				or Greater				Total
			Estimated				Estimated				Estimated
December 31, 2016	Number of		Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
(dollars in thousands)	Securities		Value		Losses		Value		Losses		Value		Losses
U. S. agency securities		27	$	88,991	$	1,764	$	3,768	$	38	$	92,759	$	1,802
Residential mortgage backed securities		112		232,347		3,110		19,402		581		251,749		3,691
Municipal bonds		16		34,743		400		-		-		34,743		400
Corporate bonds		2		4,998		11		-		-		4,998		11
		157	$	361,079	$	5,285	$	23,170	$	619	$	384,249	$	5,904

Available-for-sale Securities [Table Text Block]

	March 31, 2017				December 31, 2016
	Amortized		Estimated		Amortized		Estimated
(dollars in thousands)	Cost		Fair Value		Cost		Fair Value
U. S. agency securities maturing:
One year or less	$	82,631	$	81,401	$	83,885	$	82,548
After one year through five years		47,693		47,725		20,736		20,897
Five years through ten years		9,071		9,017		2,804		2,697
After ten years		9,765		9,765		-		-
Residential mortgage backed securities		299,757		296,925		329,606		326,239
Municipal bonds maturing:
One year or less		831		837		1,056		1,070
After one year through five years		19,913		20,801		45,808		46,865
Five years through ten years		21,437		21,794		46,668		46,839
After ten years		1,074		1,177		1,075		1,156
Corporate bonds
After one year through five years		8,513		8,647		8,008		8,079
After ten years		1,500		1,500		1,500		1,500
Other equity investments		218		218		218		218
	$	502,403	$	499,807	$	541,364	$	538,108