4. INVESTMENT SECURITIES

A summary of available for sale and held to maturity investment securities are as follows:

			Gross		Gross			Estimated
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
	(Dollars in thousands)
At September 30, 2014:
Held to Maturity:
Mortgage-backed securities - U.S. Government sponsored entities	$	242,141	$	63	$	(6,275	)	$	235,929

Available for Sale:
Debt securities:
States and political subdivisions	$	191,553	$	1,844	$	(3,238	)	$	190,159
Corporate securities	84,331		1,427		(206		)	85,552
Mortgage-backed securities:
U.S. Government sponsored entities	737,504		8,780		(5,745		)	740,539
Non-agency collateralized mortgage obligations	165,518		3,320		(1,377		)	167,461
Other	743		110		—			853
Total	$	1,179,649	$	15,481	$	(10,566	)	$	1,184,564

At December 31, 2013:
Held to Maturity:
Mortgage-backed securities - U.S. Government sponsored entities	$	252,047	$	—	$	(13,342	)	$	238,705

Available for Sale:
Debt securities:
States and political subdivisions	$	191,158	$	305	$	(12,106	)	$	179,357
Corporate securities	157,337		1,878		(1,120		)	158,095
Mortgage-backed securities:
U.S. Government sponsored entities	936,144		7,085		(15,603		)	927,626
Non-agency collateralized mortgage obligations	147,902		81		(5,937		)	142,046
Other	755		120		—			875
Total	$	1,433,296	$	9,469	$	(34,766	)	$	1,407,999

The amortized cost and estimated fair value of investment securities at September 30, 2014 by contractual maturity are shown below. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties.

	September 30, 2014
	Amortized Cost		Estimated Fair Value
	(Dollars in thousands)
Held to Maturity
Mortage-backed securities	$	242,141	$	235,929

Available for Sale
Due in one year or less	$	3,471	$	3,471
Due after one year through five years	53,494		54,842
Due after five years through ten years	99,948		99,847
Due after ten years	118,971		117,551
Mortage-backed securities	903,022		908,000
Other	743		853
Total	$	1,179,649	$	1,184,564

We sold certain available for sale investment securities during the second quarter of 2014 for gross proceeds of $162.5 million. Gross realized gains and losses on the sales of the available for sale investment securities were $0.9 million and $0.7 million, respectively. The specific identification method was used as the bases for determining the cost of all securities sold. We did not sell any available for sale securities during the first and third quarters of 2014 and the first nine months of 2013.

Investment securities of $894.1 million and $914.1 million at September 30, 2014 and December 31, 2013, respectively, were pledged to secure public funds on deposit and other long-term and short-term borrowings. None of these securities were pledged to a secured party that has the right to sell or repledge the collateral as of the same periods.

Provided below is a summary of the 218 and 321 investment securities which were in an unrealized loss position at September 30, 2014 and December 31, 2013, respectively.

	Less than 12 months					12 months or longer					Total
			Unrealized					Unrealized					Unrealized
Description of Securities	Fair Value		Losses			Fair Value		Losses			Fair Value		Losses
	(Dollars in thousands)
At September 30, 2014:
Debt securities:
States and political subdivisions	$	16,780	$	(192	)	$	85,566	$	(3,046	)	$	102,346	$	(3,238	)
Corporate securities	12,732		(75		)	8,354		(131		)	21,086		(206		)
Mortgage-backed securities:
U.S. Government sponsored entities	100,487		(577		)	461,952		(11,443		)	562,439		(12,020		)
Non-agency collateralized mortgage obligations	14,800		(52		)	47,194		(1,325		)	61,994		(1,377		)
Total temporarily impaired securities	$	144,799	$	(896	)	$	603,066	$	(15,945	)	$	747,865	$	(16,841	)

At December 31, 2013:
Debt securities:
States and political subdivisions	$	137,176	$	(8,985	)	$	32,747	$	(3,121	)	$	169,923	$	(12,106	)
Corporate securities	75,368		(1,120		)	—		—			75,368		(1,120		)
Mortgage-backed securities:
U.S. Government sponsored entities	909,585		(28,386		)	4,848		(559		)	914,433		(28,945		)
Non-agency collateralized mortgage obligations	129,991		(5,937		)	—		—			129,991		(5,937		)
Total temporarily impaired securities	$	1,252,120	$	(44,428	)	$	37,595	$	(3,680	)	$	1,289,715	$	(48,108	)

Other-Than-Temporary Impairment (“OTTI”)

Unrealized losses for all investment securities are reviewed to determine whether the losses are deemed “other-than-temporary.” Investment securities are evaluated for OTTI on at least a quarterly basis and more frequently when economic or market conditions warrant such an evaluation to determine whether a decline in their value below amortized cost is other-than-temporary. In conducting this assessment, we evaluate a number of factors including, but not limited to:

· The length of time and the extent to which fair value has been less than the amortized cost basis;

· Adverse conditions specifically related to the security, an industry, or a geographic area;

· The historical and implied volatility of the fair value of the security;

· The payment structure of the debt security and the likelihood of the issuer being able to make payments;

· Failure of the issuer to make scheduled interest or principal payments;

· Any rating changes by a rating agency; and

· Recoveries or additional decline in fair value subsequent to the balance sheet date.

The term “other-than-temporary” is not intended to indicate that the decline is permanent, but indicates that the prospects for a near-term recovery of value are not necessarily favorable, or that there is a general lack of evidence to support a realizable value equal to or greater than the carrying value of the investment. Once a decline in value is determined to be other-than-temporary, the value of the security is reduced and a corresponding charge to earnings is recognized for anticipated credit losses.

The declines in market value were primarily attributable to changes in interest rates. Because we have no intent to sell securities in an unrealized loss position and it is not more likely than not that we will be required to sell such securities before recovery of its amortized cost basis, we do not consider these investments to be other-than-temporarily impaired.