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 December 31, 2016 and 2015, by contractual maturity within each type:



	At December 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
Residential mortgage-backed securities:
Over 10 years	$	5,071	$	—	$	(3	)	$	5,068	$	—	$	—	$	—		$	—
	5,071		—		(3		)	5,068		—		—		—			—
Corporate bonds:
Within 1 year	19,810		2		(9		)	19,803		21,047		134		—			21,181
After 1 year to 5 years	—		—		—			—		19,943		1		(64		)	19,880
	19,810		2		(9		)	19,803		40,990		135		(64		)	41,061
Total	$	24,881	$	2	$	(12	)	$	24,871	$	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	15,000		20		—			15,020		10,389		—		(29		)	10,360
After 1 year to 5 years	17,265		—		(19		)	17,246		92,148		26		(378		)	91,796
	32,265		20		(19		)	32,266		102,537		26		(407		)	102,156
State and political subdivisions:
Within 1 year	964		—		(1		)	963		—		—		—			—
After 1 year to 5 years	18,705		38		(75		)	18,668		17,362		80		(29		)	17,413
After 5 years to 10 years	55,541		829		(426		)	55,944		47,969		1,188		(32		)	49,125
Over 10 years	12,663		226		(114		)	12,775		34,334		1,160		—			35,494
	87,873		1,093		(616		)	88,350		99,665		2,428		(61		)	102,032
Residential mortgage-backed securities:
After 1 year to 5 years	6,086		—		(66		)	6,020		9,713		12		(13		)	9,712
After 5 years to 10 years	23,479		—		(622		)	22,857		60		—		—			60
Over 10 years	174,388		99		(4,794		)	169,693		3,517		65		—			3,582
	203,953		99		(5,482		)	198,570		13,290		77		(13		)	13,354
Collateralized mortgage obligations:
Over 10 years	4,659		—		(105		)	4,554		3,215		—		(82		)	3,133
	4,659		—		(105		)	4,554		3,215		—		(82		)	3,133
Corporate bonds:
Within 1 year	250		—		—			250		250		—		—			250
After 1 year to 5 years	35,923		34		(241		)	35,716		19,446		25		(158		)	19,313
After 5 years to 10 years	15,193		—		(516		)	14,677		10,148		—		(266		)	9,882
Over 10 years	60,000		27		(2,472		)	57,555		60,000		—		(2,770		)	57,230
	111,366		61		(3,229		)	108,198		89,844		25		(3,194		)	86,675
Money market mutual funds:
No stated maturity	10,784		—		—			10,784		16,726		—		—			16,726
	10,784		—		—			10,784		16,726		—		—			16,726
Equity securities:
No stated maturity	411		504		—			915		426		381		—			807
	411		504		—			915		426		381		—			807
Total	$	451,311	$	1,777	$	(9,451	)	$	443,637	$	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 and mortgage-backed securities typically prepay at a rate faster than contractually due. Unrealized losses in investment securities at December 31, 2016 and 2015 do not represent other-than-temporary impairments.

Securities with a carrying value of $356.7 million and $210.1 million at December 31, 2016 and 2015, respectively, were pledged to secure public deposits and for other purposes as required by law. In addition, securities of $1.4 million were pledged to secure credit derivatives and interest rate swaps at December 31, 2016. See Note 17, "Derivative Instruments and Hedging Activities" for additional information.

The following table presents information related to sales of securities available-for-sale during the years ended December 31, 2016, 2015 and 2014:



	For the Years Ended December 31,
(Dollars in thousands)	2016		2015		2014
Securities available-for-sale:
Proceeds from sales	$	77,290	$	77,308	$	32,967
Gross realized gains on sales	600		1,295		635
Gross realized losses on sales	82		30		—
Tax expense related to net realized gains on sales	181		443		222

The Corporation did not recognize any other-than-temporary impairment charges on debt securities for the years ended December 31, 2016, 2015 and 2014. The Corporation realized other-than-temporary impairment charges to noninterest income of $0 thousand, $5 thousand, and $0 thousand on its equity portfolio during the years ended December 31, 2016, 2015 and 2014, respectively.

At December 31, 2016 and 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 December 31, 2016 and 2015 by the length of time those securities were in a continuous loss position. For the investment securities in an unrealized loss position, the Corporation has concluded, based on its analysis, that the unrealized losses are primarily caused by the movement of interest rates and current market conditions. The contractual terms of these investments do not permit the issuer to settle the securities at a price less than the par value of the investment. It is more likely than not that the Corporation will not be required to sell the investments before a recovery of carrying value.



	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 December 31, 2016
Securities Held-to-Maturity
Residential mortgage-backed securities	$	5,068	$	(3	)	$	—	$	—		$	5,068	$	(3	)
Corporate bonds	9,779		(9		)	—		—			9,779		(9		)
Total	$	14,847	$	(12	)	$	—	$	—		$	14,847	$	(12	)
Securities Available-for-Sale
U.S. government corporations and agencies	$	11,850	$	(19	)	$	—	$	—		$	11,850	$	(19	)
State and political subdivisions	40,771		(610		)	423		(6		)	41,194		(616		)
Residential mortgage-backed securities	192,782		(5,482		)	—		—			192,782		(5,482		)
Collateralized mortgage obligations	2,013		(26		)	2,542		(79		)	4,555		(105		)
Corporate bonds	58,535		(1,333		)	33,104		(1,896		)	91,639		(3,229		)
Total	$	305,951	$	(7,470	)	$	36,069	$	(1,981	)	$	342,020	$	(9,451	)

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	)