Securities

The following tables summarize the amortized costs and estimated fair values of AFS and HTM securities, as of the dates indicated:



	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
December 31, 2014:
AFS Securities:
Obligations of U.S. government-sponsored enterprises	$	4,962	$	65	$	—		$	5,027
Obligations of states and political subdivisions	26,080		697		—			26,777
Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises	377,657		5,656		(2,005		)	381,308
Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises	348,855		953		(5,911		)	343,897
Private issue collateralized mortgage obligations	5,999		63		(8		)	6,054
Total AFS securities	$	763,553	$	7,434	$	(7,924	)	$	763,063
HTM Securities:
Obligations of states and political subdivisions	$	20,179	$	265	$	(19	)	$	20,425
Total HTM securities	$	20,179	$	265	$	(19	)	$	20,425
December 31, 2013:
AFS Securities:
Obligations of states and political subdivisions	$	30,143	$	1,075	$	(11	)	$	31,207
Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises	397,409		5,528		(7,034		)	395,903
Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises	385,847		912		(12,324		)	374,435
Private issue collateralized mortgage obligations	7,329		10		(407		)	6,932
Total AFS securities	$	820,728	$	7,525	$	(19,776	)	$	808,477

At December 31, 2014 and 2013, net unrealized losses on AFS securities included in AOCI amounted to $319,000, net of a deferred tax benefit of $172,000, and $8.0 million, net of a deferred tax benefit of $4.3 million, respectively.

Impaired Investment Securities

Management periodically reviews the Company’s investment portfolio to determine the cause, magnitude and duration of declines in the fair value of each security. Thorough evaluations of the causes of the unrealized losses are performed to determine whether the impairment is temporary or other-than-temporary in nature. Considerations such as the ability of the securities to meet cash flow requirements, levels of credit enhancements, risk of curtailment, recoverability of invested amount over a reasonable period of time, and the length of time the security is in a loss position, for example, are applied in determining OTTI. Once a decline in value is determined to be other-than-temporary, the value of the security is permanently reduced and a corresponding charge to earnings is recognized.

The following table presents the estimated fair values and gross unrealized losses of investment securities that were in a continuous loss position at December 31, 2014 and 2013, by length of time that individual securities in each category have been in a continuous loss position:



	Less Than 12 Months					12 Months or More					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
December 31, 2014:
AFS Securities:
Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises	$	42,856	$	(171	)	$	125,439	$	(1,834	)	$	168,295	$	(2,005	)
Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises	75,723		(432		)	182,512		(5,479		)	258,235		(5,911		)
Private issue collateralized mortgage obligations	1,785		(8		)	—		—			1,785		(8		)
Total AFS securities	$	120,364	$	(611	)	$	307,951	$	(7,313	)	$	428,315	$	(7,924	)
HTM Securities:
Obligations of states and political subdivisions	$	5,756	$	(19	)	$	—	$	—		$	5,756	$	(19	)
Total HTM securities	$	5,756	$	(19	)	$	—	$	—		$	5,756	$	(19	)
December 31, 2013:
AFS Securities:
Obligations of states and political subdivisions	$	2,143	$	(11	)	$	—	$	—		$	2,143	$	(11	)
Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises	145,424		(4,189		)	43,915		(2,845		)	189,339		(7,034		)
Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises	239,278		(7,738		)	73,376		(4,586		)	312,654		(12,324		)
Private issue collateralized mortgage obligations	122		(4		)	4,945		(403		)	5,067		(407		)
Total AFS securities	$	386,967	$	(11,942	)	$	122,236	$	(7,834	)	$	509,203	$	(19,776	)

At December 31, 2014 and 2013, the Company held 74 and 93 investment securities with a fair value of $434.1 million and $509.2 million that were in an unrealized loss position totaling $7.9 million and $19.8 million, respectively, that are considered temporary. Of these, mortgage-backed securities and collateralized mortgage obligations with a fair value of $308.0 million and $117.3 million were in an unrealized loss position totaling $7.3 million and $7.4 million at December 31, 2014 and 2013, respectively, and that have been in an unrealized loss position for 12 months or more. The decline in the fair value of securities is reflective of current interest rates in excess of the yield received on investments and is not indicative of an overall credit deterioration or other factors with the Company's investment portfolio. At December 31, 2014, the Company had no Non-Agency investments in an unrealized loss position for 12 months or more. At December 31, 2013, Non-Agencies investments with a fair value of $5.1 million were in an unrealized loss position totaling $407,000.

Stress tests are performed monthly on the Company's Non-Agency investments, which are higher risk bonds within the investment portfolio, using current statistical data to determine expected cash flows and forecast potential losses. The results of the stress tests during 2014 and 2013 indicated potential future credit losses that were lower than previously recorded OTTI and, as such, no additional OTTI was recorded for the years ended December 31, 2014 or 2013.

The Company currently has the intent and ability to retain its investment securities in an unrealized loss position at December 31, 2014 until the decline in value has recovered.

Security Gains and Losses and OTTI of Securities

The following table details the Company’s sales of AFS investment securities, the gross realized gains and losses, and OTTI of securities:



	For The Years Ended December 31,
	2014		2013		2012
Proceeds from sales of securities	$	25,695	$	17,613	$	115,493
Gross realized gains	451		785		2,826
Gross realized losses	—		—		(289		)
OTTI	—		—		(39		)

For the years ended December 31, 2014, 2013, and 2012, the Company sold certain investment securities with a total carrying value of $25.2 million, $16.8 million, and $113.0 million, respectively, to manage its liquidity and interest rate risk. The investments securities that were sold were primarily selected based on an assessment of their prepayment speed. During 2012, one Non-Agency investment, which had previously recorded $176,000 in OTTI, was sold due its deterioration in credit quality.

Securities Pledged

At December 31, 2014 and 2013, securities with an amortized cost of $486.2 million and $479.2 million, respectively, and estimated fair values of $485.6 million and $474.7 million, respectively, were pledged to secure FHLBB advances, public deposits, and securities sold under agreements to repurchase, and for other purposes required or permitted by law.

Contractual Maturities

The amortized cost and estimated fair values of securities by contractual maturity at December 31, 2014 are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.



	Amortized Cost		Fair Value
AFS Securities
Due in one year or less	$	2,381	$	2,416
Due after one year through five years	97,183		97,441
Due after five years through ten years	96,658		98,023
Due after ten years	567,331		565,183
	$	763,553	$	763,063
HTM Securities
Due in one year or less	$	—	$	—
Due after one year through five years	—		—
Due after five years through ten years	2,316		2,330
Due after ten years	17,863		18,095
	$	20,179	$	20,425