Securities available-for-sale are reported at fair value with unrealized gains or losses included in stockholders’ equity, net of tax. Accordingly, the carrying value of such securities reflects their fair value as of March 31, 2018 and December 31, 2017. Fair value is based upon either quoted market prices, or in certain cases where there is limited activity in the market for a particular instrument, assumptions are made to determine their fair value. See Note 7 of the Notes to Consolidated Financial Statements for a further discussion.

The following table summarizes the amortized cost and fair value of securities available-for-sale at March 31, 2018 and December 31, 2017 and the corresponding amounts of gross unrealized gains and losses recognized in accumulated other comprehensive income (loss).

			Gross		Gross
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
March 31, 2018	(dollars in thousands)
Investment securities available-for-sale:
Federal agency obligations	$	53,318	$	29	$	(876	)	$	52,471
Residential mortgage pass-through securities		192,537		180		(3,960	)		188,757
Commercial mortgage pass-through securities		4,020		-		(61	)		3,959
Obligations of U.S. states and political subdivisions		128,941		1,167		(2,738	)		127,370
Trust preferred securities		4,577		120		(83	)		4,614
Corporate bonds and notes		29,302		93		(392	)		29,003
Asset-backed securities		11,463		53		(22	)		11,494
Certificates of deposit		621		2		-			623
Other securities		6,031		-		-			6,031
Total securities available-for-sale	$	430,810	$	1,644	$	(8,132	)	$	424,322

			Gross		Gross
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
December 31, 2017	(dollars in thousands)
Investment securities available-for-sale:
Federal agency obligations	$	56,297	$	141	$	(416	)	$	56,022
Residential mortgage pass-through securities		183,509		330		(1,948	)		181,891
Commercial mortgage pass-through securities		4,054		3		(3	)		4,054
Obligations of U.S. states and political subdivisions		130,723		1,739		(1,334	)		131,128
Trust preferred securities		4,577		205		(111	)		4,671
Corporate bonds and notes		29,801		163		(271	)		29,693
Asset-backed securities		12,021		66		(37	)		12,050
Certificates of deposit		621		4		-			625
Equity securities		11,843		235		(350	)		11,728
Other securities		3,422		-		-			3,422
Total securities available-for-sale	$	436,868	$	2,886	$	(4,470	)	$	435,284

Effective January 1, 2018, the Company implemented ASU 2016-01, “Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.” Under ASU 2016-01, equity securities, with certain exceptions, are to be measured at fair value with changes in fair value recognized in net income. As of March 31, 2018, the Company began separately presenting equity securities with readily determinable fair values on the Statements of Condition within the "Equity securities" caption. Net unrealized losses recognized during the period on equity securities with readily determinable fair values as of March 31, 2018 was $121 thousand.

Investment securities having a carrying value of approximately $174.9 million and $157.8 million at March 31, 2018 and December 31, 2017, respectively, were pledged to secure public deposits, borrowings, repurchase agreements, Federal Reserve Discount Window borrowings and Federal Home Loan Bank advances and for other purposes required or permitted by law. As of March 31, 2018 and December 31, 2017, there were no holdings of securities of any one issuer, other than the U.S. Government and its agencies, in an amount greater than 10% of stockholders’ equity.

The following table presents information for investments in securities available-for-sale at March 31, 2018, based on scheduled maturities. Actual maturities can be expected to differ from scheduled maturities due to prepayment or early call options of the issuer. Securities not due at a single maturity date are shown separately.

	March 31, 2018
	Amortized		Fair
	Cost		Value
	(dollars in thousands)
Investment Securities Available-for-Sale:
Due in one year or less	$	9,526	$	9,518
Due after one year through five years		28,768		28,857
Due after five years through ten years		36,318		36,369
Due after ten years		153,610		150,831
Residential mortgage pass-through securities		192,537		188,757
Commercial mortgage pass-through securities		4,020		3,959
Other securities		6,031		6,031
Total securities available-for-sale	$	430,810	$	424,322

Gross gains and losses from the sales of securities available-for-sale for the three months ended March 31, 2018 and 2017 were as follows:

The Company reviews all securities for potential recognition of other-than-temporary impairment. The Company maintains a watch list for the identification and monitoring of securities experiencing problems that require a heightened level of review. This could include credit rating downgrades.

The Company’s assessment of whether an impairment in the portfolio is other-than temporary includes factors such as whether the issuer has defaulted on scheduled payments, announced restructuring and/or filed for bankruptcy, has disclosed severe liquidity problems that cannot be resolved, disclosed deteriorating financial condition or sustained significant losses.

The Company does not believe that any of the unrealized losses, which were comprised of 152 and 112 securities as of March 31, 2018 and December 31, 2017, respectively, represent an other-than-temporary impairment (“OTTI”). The gross unrealized losses associated with U.S. Treasury and agency securities, federal agency obligations, mortgage-backed securities, corporate bonds, tax-exempt securities, asset-backed securities, and trust preferred securities are not considered to be other-than-temporary because these unrealized losses are related to changes in interest rates and do not affect the expected cash flows of the underlying collateral or issuer.

Factors which may contribute to unrealized losses include credit risk, market risk, changes in interest rates, economic cycles, and liquidity risk. The magnitude of any unrealized loss may be affected by the relative concentration of the Company’s investment in any one issuer or industry. The Company has established policies to reduce exposure through diversification of the securities portfolio including limits on concentrations in any one issuer. The Company believes the securities portfolio is prudently diversified.

The unrealized losses included in the tables below are primarily related to changes in interest rates and credit spreads. All of the Company’s securities are performing and are expected to continue to perform in accordance with their respective contractual terms and conditions. These are largely intermediate duration holdings and, in certain cases, monthly principal payments can further reduce loss exposure resulting from an increase in rates.

The Company evaluates all securities with unrealized losses quarterly to determine whether the loss is other-than-temporary. Unrealized losses in the corporate debt securities category consist primarily of senior unsecured corporate debt securities issued by large financial institutions, insurance companies and other corporate issuers. Single issuer corporate trust preferred securities are also included, and in the case of one holding the market valuation loss is largely based upon the floating rate coupon and corresponding market valuation. Neither that trust preferred issuer, nor any other corporate issuers, have defaulted on interest payments. The decline in fair value is due in large part to the lack of an active trading market for these securities, changes in prevailing interest rates, and changes in market credit spreads. Management concluded that these securities were not OTTI at March 31, 2018.

In determining whether or not securities are OTTI, the Company must exercise considerable judgment. Accordingly, there can be no assurance that the actual results will not differ from the Company’s judgments and that such differences may not require the future recognition of OTTI charges that could have a material effect on the Company’s financial position and results of operations. In addition, the value of, and the realization of any loss on, a security is subject to numerous risks as cited above.

The following tables indicate gross unrealized losses not recognized in income and fair value, aggregated by investment category and the length of time individual securities have been in a continuous unrealized loss position at March 31, 2018 and December 31, 2017: