Note 3 - Investment Securities Available-for-Sale

9 Months Ended

Sep. 30, 2015

Investments, Debt and Equity Securities [Abstract]

Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]

Note 3. Investment Securities Available-for-Sale

Amortized cost and estimated fair value of securities available-for-sale are summarized as follows:

			Gross		Gross		Estimated
September 30, 2015	Amortized		Unrealized		Unrealized		Fair
(dollars in thousands)	Cost		Gains		Losses		Value
U. S. Government agency securities	$	68,289	$	879	$	90	$	69,078
Residential mortgage backed securities		320,978		2,172		1,130		322,020
Municipal bonds		114,137		3,824		95		117,866
Corporate bonds		15,096		-		78		15,018
Other equity investments		307		37		-		344
	$	518,807	$	6,912	$	1,393	$	524,326

			Gross		Gross		Estimated
December 31, 2014	Amortized		Unrealized		Unrealized		Fair
(dollars in thousands)	Cost		Gains		Losses		Value
U. S. Government agency securities	$	29,434	$	500	$	40	$	29,894
Residential mortgage backed securities		241,120		1,716		2,516		240,320
Municipal bonds		106,983		4,850		121		111,712
Other equity investments		396		21		-		417
	$	377,933	$	7,087	$	2,677	$	382,343

In addition, at September 30, 2015, the Company held $16.9 million in equity securities in a combination of Federal Reserve Bank (“FRB”) and Federal Home Loan Bank (“FHLB”) stocks, which are required to be held for regulatory purposes, and which are not marketable.

Gross unrealized losses and fair value by length of time that the individual available-for-sale securities have been in a continuous unrealized loss position are as follows:

	Less than				12 Months
	12 Months				or Greater				Total
	Estimated				Estimated				Estimated
September 30, 2015	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
(dollars in thousands)	Value		Losses		Value		Losses		Value		Losses
U. S. Government agency securities	$	13,966	$	90	$	-	$	-	$	13,966	$	90
Residential mortgage backed securities		58,925		182		61,610		948		120,535		1,130
Municipal bonds		12,073		95		-		-		12,073		95
Corporate bonds		15,018		78		-		-		15,018		78
	$	99,982	$	445	$	61,610	$	948	$	161,592	$	1,393

	Less than				12 Months
	12 Months				or Greater				Total
	Estimated				Estimated				Estimated
December 31, 2014	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
(dollars in thousands)	Value		Losses		Value		Losses		Value		Losses
U. S. Government agency securities	$	2,001	$	7	$	1,750	$	33	$	3,751	$	40
Residential mortgage backed securities		49,644		221		86,028		2,295		135,672		2,516
Municipal bonds		4,974		14		10,915		107		15,889		121
	$	56,619	$	242	$	98,693	$	2,435	$	155,312	$	2,677

The unrealized losses that exist are generally the result of changes in market interest rates and interest spread relationships since original purchases. The weighted average duration of debt securities, which comprise 99.9% of total investment securities, is relatively short at 3.7 years. If quoted prices are not available, fair value is measured using independent pricing models or other model-based valuation techniques such as the present value of future cash flows, adjusted for the security’s credit rating, prepayment assumptions and other factors such as credit loss assumptions. The Company does not believe that the investment securities that were in an unrealized loss position as of September 30, 2015 represent an other-than-temporary impairment. The Company does not intend to sell the investments and it is more likely than not that the Company will not have to sell the securities before recovery of its amortized cost basis, which may be maturity. 

The amortized cost and estimated fair value of investments available-for-sale by contractual maturity are shown in the table below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.

	September 30, 2015				December 31, 2014
	Amortized		Estimated		Amortized		Estimated
(dollars in thousands)	Cost		Fair Value		Cost		Fair Value
U. S. Government agency securities maturing:
One year or less	$	44,981	$	45,138	$	2,998	$	3,051
After one year through five years		18,812		19,259		19,947		20,276
Five years through ten years		4,496		4,681		6,489		6,567
Residential mortgage backed securities		320,978		322,020		241,120		240,320
Municipal bonds maturing:
One year or less		4,978		5,024		2,410		2,438
After one year through five years		40,040		42,600		47,038		49,607
Five years through ten years		66,539		67,456		54,983		56,927
After ten years		2,580		2,786		2,552		2,740
Corporate bonds
After one year through five years		15,096		15,018		-		-
Other equity investments		307		344		396		417
	$	518,807	$	524,326	$	377,933	$	382,343

For the nine months ended September 30, 2015, gross realized gains on sales of investments securities were $2.5 million and gross realized losses on sales of investment securities were $294 thousand. For the nine months ended September 30, 2014, gross realized gains on sales of investment securities were $116 thousand and gross realized losses on sales of investment securities were $106 thousand.

Proceeds from sales and calls of investment securities for the nine months ended September 30, 2015 were $65.8 million, and in 2014 were $17.5 million.

The carrying value of securities pledged as collateral for certain government deposits, securities sold under agreements to repurchase, and certain lines of credit with correspondent banks at September 30, 2015 was $450.5 million, which is well in excess of required amounts in order to operationally provide significant reserve amounts for new business. As of September 30, 2015 and December 31, 2014, there were no holdings of securities of any one issuer, other than the U.S. Government and U.S. Government agency securities, which exceeded ten percent of shareholders’ equity.