Note 4. 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, 2013 and 2012, by contractual maturity within each type:


	At December 31, 2013									At December 31, 2012
(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	$	11,148	$	122	$	—		$	11,270	$	3,026	$	7	$	—		$	3,033
After 1 year to 5 years		54,855		992		(264	)		55,583		66,819		1,526		(51	)		68,294

		66,003		1,114		(264	)		66,853		69,845		1,533		(51	)		71,327

Total	$	66,003	$	1,114	$	(264	)	$	66,853	$	69,845	$	1,533	$	(51	)	$	71,327

Securities Available-for-Sale
U.S. treasuries:
After 5 years to 10 years	$	4,966	$	—	$	(258	)	$	4,708	$	4,960	$	—	$	(22	)	$	4,938

		4,966		—		(258	)		4,708		4,960		—		(22	)		4,938

U.S. government corporations and agencies:
Within 1 year		5,999		16		—			6,015		1,517		9		—			1,526
After 1 year to 5 years		112,989		114		(1,226	)		111,877		148,120		1,509		(70	)		149,559
After 5 years to 10 years		10,816		—		(560	)		10,256		20,953		109		(5	)		21,057

		129,804		130		(1,786	)		128,148		170,590		1,627		(75	)		172,142

State and political subdivisions:
Within 1 year		1,564		13		—			1,577		4,607		75		—			4,682
After 1 year to 5 years		5,305		14		(29	)		5,290		4,130		88		(19	)		4,199
After 5 years to 10 years		41,974		710		(698	)		41,986		36,499		1,245		(7	)		37,737
Over 10 years		57,899		1,227		(322	)		58,804		70,495		5,055		—			75,550

		106,742		1,964		(1,049	)		107,657		115,731		6,463		(26	)		122,168


	At December 31, 2013									At December 31, 2012
(Dollars in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Residential mortgage-backed securities:
After 5 years to 10 years		10,008		5		(53	)		9,960		20,140		777		—			20,917
Over 10 years		25,721		20		(221	)		25,520		66,962		2,861		—			69,823

		35,729		25		(274	)		35,480		87,102		3,638		—			90,740

Collateralized mortgage obligations:
After 1 year to 5 years		73		—		—			73		41		—		—			41
After 5 years to 10 years		—		—		—			—		626		7		—			633
Over 10 years		7,341		40		(253	)		7,128		25,698		645		(5	)		26,338

		7,414		40		(253	)		7,201		26,365		652		(5	)		27,012

Corporate bonds:
After 1 year to 5 years		18,838		52		(411	)		18,479		4,993		21		—			5,014
After 5 years to 10 years		16,474		4		(1,117	)		15,361		—		—		—			—

		35,312		56		(1,528	)		33,840		4,993		21		—			5,014

Money market mutual funds:
No stated maturity		16,900		—		—			16,900		4,878		—		—			4,878

		16,900		—		—			16,900		4,878		—		—			4,878

Equity securities:
No stated maturity		1,679		668		—			2,347		2,279		696		(133	)		2,842

		1,679		668		—			2,347		2,279		696		(133	)		2,842

Total	$	338,546	$	2,883	$	(5,148	)	$	336,281	$	416,898	$	13,097	$	(261	)	$	429,734

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 December 31, 2013 and 2012 do not represent other-than-temporary impairments.

Securities with a carrying value of $271.1 million and $368.2 million at December 31, 2013 and 2012, 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 years ended December 31, 2013, 2012, and 2011:


	For the Years Ended December 31,
(Dollars in thousands)	2013		2012		2011
Securities available-for-sale:
Proceeds from sales	$	76,361	$	57,186	$	40,481
Gross realized gains on sales		3,396		1,201		1,428
Gross realized losses on sales		7		896		11
Tax expense related to net realized gains on sales		1,186		107		496

The Corporation realized other-than-temporary impairment charges of $0 thousand and $13 thousand, respectively, to noninterest income on its equity portfolio during the years ended December 31, 2013 and 2012. As such, in 2012, the Corporation determined that it was probable that the fair value of certain equity securities would not recover to the Corporation’s cost basis within a reasonable period of time due to a decline in the financial stability of the underlying companies.

At December 31, 2013 and 2012, 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, 2013 and 2012 by the length of time those securities were in a continuous loss position:


	At December 31, 2013
	Less than Twelve Months					Twelve Months or Longer					Total
(Dollars in thousands)	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. treasuries	$	4,708	$	(258	)	$	—	$	—		$	4,708	$	(258	)
U.S. government corporations and agencies		101,813		(1,786	)		—		—			101,813		(1,786	)
State and political subdivisions		30,233		(1,049	)		—		—			30,233		(1,049	)
Residential mortgage-backed securities		29,444		(274	)		—		—			29,444		(274	)
Collateralized mortgage obligations		4,091		(253	)		—		—			4,091		(253	)
Corporate bonds		46,499		(1,792	)		—		—			46,499		(1,792	)

Total	$	216,788	$	(5,412	)	$	—	$	—		$	216,788	$	(5,412	)


	At December 31, 2012
	Less than Twelve Months					Twelve Months or Longer					Total
(Dollars in thousands)	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. treasuries	$	4,938	$	(22	)	$	—	$	—		$	4,938	$	(22	)
U.S. government corporations and agencies		36,793		(75	)		—		—			36,793		(75	)
State and political subdivisions		4,574		(14	)		480		(12	)		5,054		(26	)
Collateralized mortgage obligations		5,006		(5	)		—		—			5,006		(5	)
Corporate bonds		10,410		(51	)		—		—			10,410		(51	)
Equity securities		976		(133	)		—		—			976		(133	)

Total	$	62,697	$	(300	)	$	480	$	(12	)	$	63,177	$	(312	)