Investment Securities

The following table shows the amortized cost and the estimated fair value of the held-to-maturity securities and available-for-sale securities at March 31, 2016 and December 31, 2015, by contractual maturity within each type:



	At March 31, 2016									At December 31, 2015
(Dollars in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Securities Held-to-Maturity
Corporate bonds:
Within 1 year	$	26,924	$	114	$	—		$	27,038	$	21,047	$	134	$	—		$	21,181
After 1 year to 5 years	10,008		26		(41		)	9,993		19,943		1		(64		)	19,880
	36,932		140		(41		)	37,031		40,990		135		(64		)	41,061
Total	$	36,932	$	140	$	(41	)	$	37,031	$	40,990	$	135	$	(64	)	$	41,061
Securities Available-for-Sale
U.S. treasuries:
After 1 year to 5 years	$	—	$	—	$	—		$	—	$	4,978	$	—	$	(91	)	$	4,887
	—		—		—			—		4,978		—		(91		)	4,887
U.S. government corporations and agencies:
Within 1 year	10,278		2		—			10,280		10,389		—		(29		)	10,360
After 1 year to 5 years	57,085		302		—			57,387		92,148		26		(378		)	91,796
	67,363		304		—			67,667		102,537		26		(407		)	102,156
State and political subdivisions:
After 1 year to 5 years	17,125		134		(12		)	17,247		17,362		80		(29		)	17,413
After 5 years to 10 years	50,335		1,382		(17		)	51,700		47,969		1,188		(32		)	49,125
Over 10 years	32,560		1,301		—			33,861		34,334		1,160		—			35,494
	100,020		2,817		(29		)	102,808		99,665		2,428		(61		)	102,032
Residential mortgage-backed securities:
After 1 year to 5 years	4,920		6		—			4,926		9,713		12		(13		)	9,712
After 5 years to 10 years	59		1		—			60		60		—		—			60
Over 10 years	3,497		91		—			3,588		3,517		65		—			3,582
	8,476		98		—			8,574		13,290		77		(13		)	13,354
Collateralized mortgage obligations:
Over 10 years	3,080		—		(24		)	3,056		3,215		—		(82		)	3,133
	3,080		—		(24		)	3,056		3,215		—		(82		)	3,133
Corporate bonds:
Within 1 year	250		—		—			250		250		—		—			250
After 1 year to 5 years	18,862		142		(44		)	18,960		19,446		25		(158		)	19,313
After 5 years to 10 years	15,122		95		(63		)	15,154		10,148		—		(266		)	9,882
Over 10 years	60,000		857		(3,218		)	57,639		60,000		—		(2,770		)	57,230
	94,234		1,094		(3,325		)	92,003		89,844		25		(3,194		)	86,675
Money market mutual funds:
No stated maturity	17,563		—		—			17,563		16,726		—		—			16,726
	17,563		—		—			17,563		16,726		—		—			16,726
Equity securities:
No stated maturity	426		328		—			754		426		381		—			807
	426		328		—			754		426		381		—			807
Total	$	291,162	$	4,641	$	(3,378	)	$	292,425	$	330,681	$	2,937	$	(3,848	)	$	329,770

Expected maturities may differ from contractual maturities because debt issuers may have the right to call or prepay obligations without call or prepayment penalties. Unrealized losses in investment securities at March 31, 2016 and December 31, 2015 do not represent other-than-temporary impairments.

Securities with a carrying value of $157.4 million and $210.1 million at March 31, 2016 and December 31, 2015, respectively, were pledged to secure public deposits and for other purposes as required by law.

The following table presents information related to sales of securities available-for-sale during the three months ended March 31, 2016 and 2015:



	Three Months Ended March 31,
(Dollars in thousands)	2016		2015
Securities available-for-sale:
Proceeds from sales	$	53,181	$	271
Gross realized gains on sales	106		91
Gross realized losses on sales	62		—
Tax expense related to net realized gains on sales	15		32

Management evaluates debt securities, which are comprised of U.S. government, government sponsored agencies, municipalities, corporate bonds and other issuers, for other-than-temporary impairment by considering the current economic conditions, the length of time and the extent to which the fair value has been less than cost, market interest rates and the bond rating of each security. All of the debt securities are rated as investment grade and management believes that it will not incur any losses. The unrealized losses on the Corporation’s investments in debt securities are temporary in nature since they are primarily related to market interest rates and are not related to the underlying credit quality of the issuers. The Corporation does not have the intent to sell the debt securities and believes it is more likely than not, that it will not have to sell the securities before recovery of their cost basis. The Corporation did not recognize any other-than-temporary impairment charges on debt securities for the three months ended March 31, 2016 and 2015.

The Corporation evaluates its equity securities for other-than-temporary impairment and recognizes other-than-temporary impairment charges when it has determined that it is probable that the fair value of certain equity securities will not recover to the Corporation’s cost basis in the individual securities within a reasonable period of time due to a decline in the financial stability of the underlying companies. Management evaluates the near-term prospects of the issuers in relation to the severity and duration of the impairment. The Corporation has the intent and ability to hold these securities until recovery of the Corporation’s cost basis occurs. The Corporation did not recognize any other-than-temporary impairment charges on its equity portfolio during the three months ended March 31, 2016 and 2015.

At March 31, 2016 and December 31, 2015, there were no investments in any single non-federal issuer representing more than 10% of shareholders’ equity.

The following table shows the fair value of securities that were in an unrealized loss position at March 31, 2016 and December 31, 2015 by the length of time those securities were in a continuous loss position:



	Less than Twelve Months					Twelve Months or Longer					Total
(Dollars in thousands)	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
At March 31, 2016
Securities Held-to-Maturity
Corporate bonds	$	—	$	—		$	4,965	$	(41	)	$	4,965	$	(41	)
Total	$	—	$	—		$	4,965	$	(41	)	$	4,965	$	(41	)
Securities Available-for-Sale
U.S. government corporations and agencies	$	5,126	$	—		$	5,000	$	—		$	10,126	$	—
State and political subdivisions	5,669		(8		)	2,620		(21		)	8,289		(29		)
Collateralized mortgage obligations	—		—			3,056		(24		)	3,056		(24		)
Corporate bonds	42,051		(3,231		)	11,251		(94		)	53,302		(3,325		)
Equity securities	4		—			—		—			4		—
Total	$	52,850	$	(3,239	)	$	21,927	$	(139	)	$	74,777	$	(3,378	)
At December 31, 2015
Securities Held-to-Maturity
Corporate bonds	$	12,078	$	(9	)	$	4,953	$	(55	)	$	17,031	$	(64	)
Total	$	12,078	$	(9	)	$	4,953	$	(55	)	$	17,031	$	(64	)
Securities Available-for-Sale
U.S. treasuries	$	—	$	—		$	4,887	$	(91	)	$	4,887	$	(91	)
U.S. government corporations and agencies	72,157		(379		)	4,972		(28		)	77,129		(407		)
State and political subdivisions	10,251		(49		)	1,335		(12		)	11,586		(61		)
Residential mortgage-backed securities	4,751		(13		)	—		—			4,751		(13		)
Collateralized mortgage obligations	—		—			3,133		(82		)	3,133		(82		)
Corporate bonds	72,234		(2,941		)	10,669		(253		)	82,903		(3,194		)
Total	$	159,393	$	(3,382	)	$	24,996	$	(466	)	$	184,389	$	(3,848	)