INVESTMENTS

The following table presents the amortized cost, gross unrealized gains and losses and fair value of securities available-for-sale:



	September 30, 2012
(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Available for sale securities:
Obligations of U.S. Government sponsored enterprises	$	124,721	$	3,284	$	—		$	128,005
Obligations of states and political subdivisions	43,720		2,429		(360		)	45,789
Residential mortgage-backed securities	426,992		9,773		(202		)	436,563
	$	595,433	$	15,486	$	(562	)	$	610,357

	December 31, 2011
(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Available for sale securities:
Obligations of U.S. Government sponsored enterprises	$	126,305	$	678	$	(66	)	$	126,917
Obligations of states and political subdivisions	38,489		1,729		(381		)	39,837
Residential mortgage-backed securities	422,761		5,269		(1,602		)	426,428
	$	587,555	$	7,676	$	(2,049	)	$	593,182

At September 30, 2012, and December 31, 2011, there were no holdings of securities of any one issuer in an amount greater than 10% of shareholders’ equity, other than the U.S. government agencies and sponsored enterprises. The residential mortgage-backed securities are all issued by U.S. government sponsored enterprises. Available for sale securities having a fair value of $271.8 million and $287.8 million at September 30, 2012, and December 31, 2011, respectively, were pledged as collateral to secure deposits of public institutions and for other purposes as required by law or contract provisions.

The amortized cost and estimated fair value of debt securities classified as available for sale at September 30, 2012, by contractual maturity, are shown below. Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. The weighted average life of the mortgage-backed securities is approximately 3 years.



(in thousands)	Amortized Cost		Estimated Fair Value
Due in one year or less	$	2,299	$	2,325
Due after one year through five years	118,719		122,152
Due after five years through ten years	42,958		45,014
Due after ten years	4,465		4,303
Mortgage-backed securities	426,992		436,563
	$	595,433	$	610,357

The following table represents a summary of available-for-sale investment securities that had an unrealized loss:



	September 30, 2012
	Less than 12 months				12 months or more				Total
(in thousands)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Obligations of the state and political subdivisions	$	540	$	2	$	3,388	$	358	$	3,928	$	360
Residential mortgage-backed securities	16,764		71		9,161		131		25,925		202
	$	17,304	$	73	$	12,549	$	489	$	29,853	$	562

	December 31, 2011
	Less than 12 months				12 months or more				Total
(in thousands)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Obligations of U.S. government sponsored enterprises	$	23,389	$	66	$	—	$	—	$	23,389	$	66
Obligations of the state and political subdivisions	1,503		8		3,027		373		4,530		381
Residential mortgage-backed securities	86,954		1,598		4,203		4		91,157		1,602
	$	111,846	$	1,672	$	7,230	$	377	$	119,076	$	2,049

The unrealized losses at both September 30, 2012, and December 31, 2011, were primarily attributable to changes in market interest rates since the securities were purchased. Management systematically evaluates investment securities for other-than-temporary declines in fair value on a quarterly basis. This analysis requires management to consider various factors, which include (1) the present value of the cash flows expected to be collected compared to the amortized cost of the security, (2) duration and magnitude of the decline in value, (3) the financial condition of the issuer or issuers, (4) structure of the security and (5) the intent to sell the security or whether it is more likely than not that the Company would be required to sell the security before its anticipated recovery in market value. At September 30, 2012, management performed its quarterly analysis of all securities with an unrealized loss and concluded no individual securities were other-than-temporarily impaired.

The gross gains and gross losses realized from sales of available-for-sale investment securities were as follows:



	Three months ended September 30,				Nine months ended September 30,
(in thousands)	2012		2011		2012			2011
Gross gains realized	$	—	$	768	$	1,399		$	1,448
Gross losses realized	—		—		(243		)	—
Proceeds from sales	—		49,033		110,876			84,456