Investment Securities

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



(Dollars in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
June 30, 2015
U.S. Treasury and Federal agencies securities	$	383,369	$	3,443	$	(898	)	$	385,914
U.S. States and political subdivisions securities	121,353		2,629		(274		)	123,708
Mortgage-backed securities — Federal agencies	232,454		4,369		(1,573		)	235,250
Corporate debt securities	33,326		271		(20		)	33,577
Foreign government and other securities	800		7		—			807
Total debt securities	771,302		10,719		(2,765		)	779,256
Marketable equity securities	1,893		5,408		(86		)	7,215
Total investment securities available-for-sale	$	773,195	$	16,127	$	(2,851	)	$	786,471

December 31, 2014
U.S. Treasury and Federal agencies securities	$	371,878	$	3,593	$	(1,968	)	$	373,503
U.S. States and political subdivisions securities	121,510		3,392		(214		)	124,688
Mortgage-backed securities — Federal agencies	248,299		5,490		(781		)	253,008
Corporate debt securities	31,677		281		(26		)	31,932
Foreign government and other securities	800		11		—			811
Total debt securities	774,164		12,767		(2,989		)	783,942
Marketable equity securities	1,893		5,285		(2		)	7,176
Total investment securities available-for-sale	$	776,057	$	18,052	$	(2,991	)	$	791,118

At June 30, 2015 and December 31, 2014, 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 June 30, 2015. 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	$	83,048	$	83,639
Due after one year through five years	429,898		434,308
Due after five years through ten years	25,902		26,059
Due after ten years	—		—
Mortgage-backed securities	232,454		235,250
Total debt securities available-for-sale	$	771,302	$	779,256

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 for the six months ended June 30, 2014 reflect the sale of marketable equity securities.



	Three Months Ended June 30,				Six Months Ended June 30,
(Dollars in thousands)	2015		2014		2015		2014
Gross realized gains	$	4	$	—	$	4	$	963
Gross realized losses	—		—		—		—
Net realized gains (losses)	$	4	$	—	$	4	$	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
June 30, 2015
U.S. Treasury and Federal agencies securities	$	24,563	$	(72	)	$	104,158	$	(826	)	$	128,721	$	(898	)
U.S. States and political subdivisions securities	31,585		(241		)	2,068		(33		)	33,653		(274		)
Mortgage-backed securities - Federal agencies	62,521		(639		)	18,952		(934		)	81,473		(1,573		)
Corporate debt securities	3,833		(19		)	999		(1		)	4,832		(20		)
Foreign government and other securities	—		—			—		—			—		—
Total debt securities	122,502		(971		)	126,177		(1,794		)	248,679		(2,765		)
Marketable equity securities	560		(85		)	3		(1		)	563		(86		)
Total investment securities available-for-sale	$	123,062	$	(1,056	)	$	126,180	$	(1,795	)	$	249,242	$	(2,851	)

December 31, 2014
U.S. Treasury and Federal agencies securities	$	54,944	$	(148	)	$	115,195	$	(1,820	)	$	170,139	$	(1,968	)
U.S. States and political subdivisions securities	16,805		(112		)	8,333		(102		)	25,138		(214		)
Mortgage-backed securities - Federal agencies	21,754		(62		)	32,781		(719		)	54,535		(781		)
Corporate debt securities	3,072		(26		)	—		—			3,072		(26		)
Foreign government and other securities	—		—			—		—			—		—
Total debt securities	96,575		(348		)	156,309		(2,641		)	252,884		(2,989		)
Marketable equity securities	—		—			3		(2		)	3		(2		)
Total investment securities available-for-sale	$	96,575	$	(348	)	$	156,312	$	(2,643	)	$	252,887	$	(2,991	)

The initial indication of other-than-temporary-impairment (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 OTTI write-downs in 2015 or 2014.

At June 30, 2015, 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. 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 June 30, 2015 and December 31, 2014, investment securities with carrying values of $227.29 million and $231.50 million, respectively, were pledged as collateral for security repurchase agreements and for other purposes.