Note 3: Securities

The amortized cost, unrealized gains and losses and fair values of securities classified available for sale are summarized as follows:

			Gross		Gross
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
	(dollars in thousands)
June 30, 2013:
U.S. Treasury securities	$	103,097	$	301	$	(223	)	$	103,175
Obligations of U.S. government corporations and agencies	311,442		3,723		(525		)	314,640
Obligations of states and political subdivisions	294,299		3,462		(2,694		)	295,067
Residential mortgage-backed securities	173,456		4,022		(237		)	177,241
Corporate debt securities	24,439		87		(90		)	24,436
Total debt securities	906,733		11,595		(3,769		)	914,559
Mutual funds and other equity securities	5,029		1,977		—			7,006

	$	911,762	$	13,572	$	(3,769	)	$	921,565

			Gross		Gross
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
	(dollars in thousands)
December 31, 2012:
U.S. Treasury securities	$	103,353	$	1,303	$	—		$	104,656
Obligations of U.S. government corporations and agencies	363,583		6,616		(5		)	370,194
Obligations of states and political subdivisions	274,350		6,176		(238		)	280,288
Residential mortgage-backed securities	210,139		7,576		—			217,715
Corporate debt securities	24,601		139		(26		)	24,714
Total debt securities	976,026		21,810		(269		)	997,567
Mutual funds and other equity securities	2,451		1,479		—			3,930

	$	978,477	$	23,289	$	(269	)	$	1,001,497

The amortized cost and fair value of debt securities available for sale as of June 30, 2013, by contractual maturity, are shown below. Mutual funds and other equity securities do not have stated maturity dates and therefore are not included in the following maturity summary. Mortgages underlying the residential mortgage-backed securities may be called or prepaid without penalties; therefore, actual maturities could differ from the contractual maturities. All residential mortgage-backed securities were issued by U.S. government agencies and corporations.

	Amortized		Fair
	Cost		Value
	(dollars in thousands)
Due in one year or less	$	160,492	$	161,813
Due after one year through five years	494,329		497,057
Due after five years through ten years	195,331		197,695
Due after ten years	56,581		57,994
	$	906,733	$	914,559

Realized gains and losses related to sales of securities are summarized as follows:

	Three Months Ended June 30,
	2013		2012
	(dollars in thousands)

Gross security gains	$	—	$	64
Gross security (losses)	—		—
Net security gains	$	—	$	64

	Six Months Ended June 30,
	2013		2012
	(dollars in thousands)

Gross security gains	$	—	$	64
Gross security (losses)	—		—
Net security gains	$	—	$	64

The tax provision for the net realized gains was insignificant for the three and six months ended June 30, 2012.

Investment securities with carrying amounts of $471.5 million and $489.1 million on June 30, 2013 and December 31, 2012, respectively, were pledged as collateral for public deposits, securities sold under agreements to repurchase and for other purposes as required or permitted by law.

Information pertaining to securities with gross unrealized losses at June 30, 2013 and December 31, 2012 aggregated by investment category and length of time that individual securities have been in a continuous loss position follows:

	Less than 12 months				Greater than 12 months				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
	(dollars in thousands)
June 30, 2013:
U.S. Treasury securities	$	51,050	$	223	$	—	$	—	$	51,050	$	223
Obligations of U.S. government corporations and agencies	25,119		525		—		—		25,119		525
Obligations of states and political subdivisions	129,570		2,617		4,489		77		134,059		2,694
Residential mortgage-backed securities	12,829		237		—		—		12,829		237
Corporate debt securities	20,186		90		—		—		20,186		90
Total temporarily impaired securities	$	238,754	$	3,692	$	4,489	$	77	$	243,243	$	3,769

	Less than 12 months				Greater than 12 months				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
	(dollars in thousands)
December 31, 2012:
Obligations of U.S. government corporations and agencies	$	10,155	$	5	$	—	$	—	$	10,155	$	5
Obligations of states and political subdivisions	37,958		189		3,311		49		41,269		238
Corporate debt securities	15,207		26		—		—		15,207		26
Total temporarily impaired securities	$	63,320	$	220	$	3,311	$	49	$	66,631	$	269

Management evaluates securities for other-than-temporary impairment at least on a quarterly basis, and more frequently when economic or market concerns warrant such evaluation. Consideration is given to the length of time and extent to which the fair value has been less than cost, the financial condition and near-term prospects of the issuer, and whether the Company has the intent to sell the security and it is more-likely-than-not we will have to sell the security before recovery of its cost basis.

The total number of securities in the investment portfolio in an unrealized loss position as of June 30, 2013 was 356, and represented a loss of 1.5% of the aggregate carrying value. Based upon a review of unrealized loss circumstances, the unrealized losses resulted from changes in market interest rates and liquidity, not from changes in the probability of receiving the contractual cash flows. The Company does not intend to sell the securities and it is more-likely-than-not that the Company will recover the amortized cost prior to being required to sell the securities. Full collection of the amounts due according to the contractual terms of the securities is expected; therefore, the Company does not consider these investments to be other-than-temporarily impaired at June 30, 2013.