The following tables present the amortized cost and fair value of available-for-sale securities as of the dates presented:



	June 30, 2015									December 31, 2014
(dollars in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury securities	$	14,893	$	125	$	—		$	15,018	$	14,873	$	7	$	—		$	14,880
Obligations of U.S. government corporations and agencies	267,604		2,935		(427		)	270,112		268,029		2,334		(1,078		)	269,285
Collateralized mortgage obligations of U.S. government corporations and agencies	138,160		1,549		(132		)	139,577		116,897		1,257		(148		)	118,006
Residential mortgage-backed securities of U.S. government corporations and agencies	42,155		1,450		(186		)	43,419		45,274		1,548		(154		)	46,668
Commercial mortgage-backed securities of U.S. government corporations and agencies	49,737		312		(373		)	49,676		39,834		232		(393		)	39,673
Obligations of states and political subdivisions	136,540		3,927		(520		)	139,947		136,977		5,789		(64		)	142,702
Debt Securities	649,089		10,298		(1,638		)	657,749		621,884		11,167		(1,837		)	631,214
Marketable equity securities	7,579		1,296		—			8,875		7,579		1,480		—			9,059
Total	$	656,668	$	11,594	$	(1,638	)	$	666,624	$	629,463	$	12,647	$	(1,837	)	$	640,273

Realized gains and losses on the sale of securities are determined using the specific-identification method. The following table shows the composition of gross and net realized gains and losses for the periods presented:



	Three Months Ended June 30,					Six Months Ended June 30,
(dollars in thousands)	2015			2014		2015			2014
Gross realized gains	$	—		$	40	$	—		$	41
Gross realized losses	34			—		34			—
Net Realized Gains	$	(34	)	$	40	$	(34	)	$	41

The following tables present the fair value and the age of gross unrealized losses by investment category as of the dates presented:



	June 30, 2015
	Less Than 12 Months						12 Months or More						Total
(dollars in thousands)	Number of Securities	Fair Value		Unrealized Losses			Number of Securities	Fair Value		Unrealized Losses			Number of Securities	Fair Value		Unrealized Losses
Obligations of U.S. government corporations and agencies	4	$	33,489	$	(215	)	4	$	30,033	$	(212	)	8	$	63,522	$	(427	)
Collateralized mortgage obligations of U.S. government corporations and agencies	2	17,288		(132		)	—	—		—			2	17,288		(132		)
Residential mortgage-backed securities of U.S. government corporations and agencies	2	10,704		(186		)	—	—		—			2	10,704		(186		)
Commercial mortgage-backed securities of U.S. government corporations and agencies	2	20,976		(180		)	1	9,610		(193		)	3	30,586		(373		)
Obligations of states and political subdivisions	10	42,967		(520		)	—	—		—			10	42,967		(520		)
Total Temporarily Impaired Securities	20	$	125,424	$	(1,233	)	5	$	39,643	$	(405	)	25	$	165,067	$	(1,638	)



	December 31, 2014
	Less Than 12 Months						12 Months or More						Total
(dollars in thousands)	Number of Securities	Fair Value		Unrealized Losses			Number of Securities	Fair Value		Unrealized Losses			Number of Securities	Fair Value		Unrealized Losses
Obligations of U.S. government corporations and agencies	4	$	39,745	$	(207	)	8	$	63,149	$	(871	)	12	$	102,894	$	(1,078	)
Collateralized mortgage obligations of U.S. government corporations and agencies	1	9,323		(148		)	—	—		—			1	9,323		(148		)
Residential mortgage-backed securities of U.S. government corporations and agencies	—	—		—			1	8,982		(154		)	1	8,982		(154		)
Commercial mortgage-backed securities of U.S. government corporations and agencies	1	9,998		(25		)	2	20,640		(368		)	3	30,638		(393		)
Obligations of states and political subdivisions	1	263		(1		)	2	10,756		(63		)	3	11,019		(64		)
Total Temporarily Impaired Securities	7	$	59,329	$	(381	)	13	$	103,527	$	(1,456	)	20	$	162,856	$	(1,837	)

We do not believe any individual unrealized loss as of June 30, 2015 represents an other than temporary impairment. As of June 30, 2015, the unrealized losses on 25 debt securities were attributable to changes in interest rates and not related to the credit quality of these securities. All debt securities are determined to be investment grade and are paying principal and interest according to the contractual terms of the security. There were no unrealized losses on marketable equity securities as of June 30, 2015. We do not intend to sell and it is not more likely than not that we will be required to sell any of the securities, referenced in the table above, in an unrealized loss position before recovery of their amortized cost.

The following table displays net unrealized gains and losses, net of tax on securities available for sale included in accumulated other comprehensive (loss)/income for the periods presented:



	June 30, 2015							December 31, 2014
(dollars in thousands)	Gross Unrealized Gains		Gross Unrealized Losses			Net Unrealized Gains/ (Losses)		Gross Unrealized Gains		Gross Unrealized Losses			Net Unrealized Gains/ (Losses)
Total unrealized gains/(losses) on securities available-for-sale	$	11,594	$	(1,638	)	$	9,956	$	12,647	$	(1,837	)	$	10,810
Income tax expense/(benefit)	4,058		(573		)	3,485		4,426		(643		)	3,783
Net unrealized gains/(losses), net of tax included in accumulated other comprehensive income/(loss)	$	7,536	$	(1,065	)	$	6,471	$	8,221	$	(1,194	)	$	7,027

The amortized cost and fair value of securities available-for-sale at June 30, 2015 by contractual maturity are included in the table below. Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties.



	June 30, 2015
(dollars in thousands)	Amortized Cost		Fair Value
Obligations of the U.S. Treasury, U.S. government corporations and agencies, and obligations of states and political subdivisions
Due in one year or less	$	29,892	$	30,223
Due after one year through five years	215,038		217,163
Due after five years through ten years	80,796		82,406
Due after ten years	93,311		95,285
	419,037		425,077
Collateralized mortgage obligations of U.S. government corporations and agencies	138,160		139,577
Residential mortgage-backed securities of U.S. government corporations and agencies	42,155		43,419
Commercial mortgage-backed securities of U.S. government corporations and agencies	49,737		49,676
Debt Securities	649,089		657,749
Marketable equity securities	7,579		8,875
Total	$	656,668	$	666,624

At June 30, 2015 and December 31, 2014, securities with carrying values of $326.3 million and $289.1 million were pledged for various regulatory and legal requirements.