Investment Securities

The following table shows investment securities available-for-sale.



(Dollars in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
March 31, 2014
U.S. Treasury and Federal agencies securities	$	400,973	$	4,440	$	(4,023	)	$	401,390
U.S. States and political subdivisions securities	124,174		3,775		(555		)	127,394
Mortgage-backed securities — Federal agencies	266,392		5,395		(2,267		)	269,520
Corporate debt securities	31,875		308		(43		)	32,140
Foreign government and other securities	700		2		—			702
Total debt securities	824,114		13,920		(6,888		)	831,146
Marketable equity securities	1,893		6,560		(2		)	8,451
Total investment securities available-for-sale	$	826,007	$	20,480	$	(6,890	)	$	839,597

December 31, 2013
U.S. Treasury and Federal agencies securities	$	394,558	$	5,008	$	(4,527	)	$	395,039
U.S. States and political subdivisions securities	120,416		3,670		(847		)	123,239
Mortgage-backed securities — Federal agencies	273,495		5,148		(3,563		)	275,080
Corporate debt securities	30,828		241		(4		)	31,065
Foreign government and other securities	700		9		—			709
Total debt securities	819,997		14,076		(8,941		)	825,132
Marketable equity securities	2,166		5,404		(2		)	7,568
Total investment securities available-for-sale	$	822,163	$	19,480	$	(8,943	)	$	832,700

At March 31, 2014 and December 31, 2013, the residential mortgage-backed securities held by the Company consisted primarily of GNMA, FNMA and FHLMC pass-through certificates which are guaranteed by those respective agencies of the United States government (Government Sponsored Enterprise, GSEs).

The following table shows the contractual maturities of investments in securities available-for-sale at March 31, 2014. 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.



(Dollars in thousands)	Amortized Cost		Fair Value
Due in one year or less	$	37,524	$	38,027
Due after one year through five years	400,315		404,908
Due after five years through ten years	117,501		116,329
Due after ten years	2,382		2,362
Mortgage-backed securities	266,392		269,520
Total debt securities available-for-sale	$	824,114	$	831,146

The following table shows the gross realized gains and losses on sale of securities from the securities available-for-sale portfolio, including marketable equity securities. Realized gains and losses on the sales of all securities are computed using the specific identification cost basis. The gross gains and losses for the three months ended March 31, 2014 reflect the sale of marketable equity securities.



	Three Months Ended March 31,
(Dollars in thousands)	2014		2013
Gross realized gains	$	963	$	—
Gross realized losses	—		—
Net realized gains (losses)	$	963	$	—

The following table summarizes gross unrealized losses and fair value by investment category and age.



	Less than 12 Months					12 months or Longer					Total
(Dollars in thousands)	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
March 31, 2014
U.S. Treasury and Federal agencies securities	$	210,143	$	(3,876	)	$	15,044	$	(147	)	$	225,187	$	(4,023	)
U.S. States and political subdivisions securities	34,278		(528		)	915		(27		)	35,193		(555		)
Mortgage-backed securities - Federal agencies	72,185		(1,438		)	14,813		(829		)	86,998		(2,267		)
Corporate debt securities	6,066		(43		)	—		—			6,066		(43		)
Foreign government and other securities	100		—			—		—			100		—
Total debt securities	322,772		(5,885		)	30,772		(1,003		)	353,544		(6,888		)
Marketable equity securities	—		—			4		(2		)	4		(2		)
Total investment securities available-for-sale	$	322,772	$	(5,885	)	$	30,776	$	(1,005	)	$	353,548	$	(6,890	)

December 31, 2013
U.S. Treasury and Federal agencies securities	$	153,868	$	(4,404	)	$	15,085	$	(123	)	$	168,953	$	(4,527	)
U.S. States and political subdivisions securities	37,115		(814		)	1,419		(33		)	38,534		(847		)
Mortgage-backed securities - Federal agencies	99,488		(3,099		)	5,352		(464		)	104,840		(3,563		)
Corporate debt securities	6,332		(4		)	—		—			6,332		(4		)
Foreign government and other securities	—		—			—		—			—		—
Total debt securities	296,803		(8,321		)	21,856		(620		)	318,659		(8,941		)
Marketable equity securities	—		—			4		(2		)	4		(2		)
Total investment securities available-for-sale	$	296,803	$	(8,321	)	$	21,860	$	(622	)	$	318,663	$	(8,943	)

The initial indication of OTTI for both debt and equity securities is a decline in fair value below amortized cost. Quarterly, the impaired securities are analyzed on a qualitative and quantitative basis in determining OTTI. Declines in the fair value of available-for-sale debt securities below their cost that are deemed to be other-than-temporary are reflected in earnings as realized losses to the extent the impairment is related to credit losses. The amount of impairment related to other factors is recognized in other comprehensive income. In estimating OTTI impairment losses, the Company considers among other things, (i) the length of time and the extent to which fair value has been less than cost, (ii) the financial condition and near-term prospects of the issuer, and (iii) whether it is more likely than not that the Company will not have to sell any such securities before a recovery of cost.

There were no other-than-temporary-impairment (OTTI) write-downs in 2014 or 2013.

At March 31, 2014, the Company does not have the intent to sell any of the available-for-sale securities in the table above and believes that it is more likely than not, that it will not have to sell any such securities before an anticipated recovery of cost. Primarily the unrealized losses on debt securities are due to increases in market rates over the yields available at the time the underlying securities were purchased and market illiquidity on auction rate securities which are reflected in U.S. States and political subdivisions. The fair value is expected to recover on all debt securities as they approach their maturity date or re-pricing date or if market yields for such investments decline. The Company does not believe any of the securities are impaired due to reasons of credit quality.

At March 31, 2014 and December 31, 2013, investment securities with carrying values of $248.11 million and $237.42 million, respectively, were pledged as collateral for security repurchase agreements and for other purposes.