The following table summarizes the amortized cost and fair value of the securities available-for-sale portfolio at March 31, 2020 and December 31, 2019 and the corresponding amounts of gross unrealized gains and losses recognized in accumulated other comprehensive income.


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
March 31, 2020
Mortgage-backed securities: residential	$	286,307	$	8,369	$	(4)	$	294,672
Mortgage-backed securities: commercial	17,445		336		(86)		17,695
Corporate notes	4,500		108		(85)		4,523
State and political subdivisions	230,728		3,447		(7,840)		226,335
Total	$	538,980	$	12,260	$	(8,015)	$	543,225


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
December 31, 2019
Mortgage-backed securities: residential	$	374,923	$	1,876	$	(856)	$	375,943
Mortgage-backed securities: commercial	17,858		56		(134)		17,780
Corporate notes	32,825		539		(3)		33,361
State and political subdivisions	222,624		2,566		(142)		225,048
Total	$	648,230	$	5,037	$	(1,135)	$	652,132

The proceeds from sales, calls, and prepayments of available for sale securities and the associated gains and losses were as follows:


			Three Months Ended March 31,
	2020		2019
Proceeds	$	102,426	$	259,613
Gross gains	1,424		1,801
Gross losses	(28)		(1,652)

The amortized cost and fair value of the investment securities portfolio are shown by contractual maturity. Securities not due at a single maturity date, primarily mortgage-backed securities, are shown separately.


	March 31, 2020
	Amortized Cost		Fair Value
Available-for-sale
Over one year through five years	$	1,606	$	1,642
Over five years through ten years	8,959		8,821
Over ten years	224,663		220,395
Mortgage-backed securities: residential	286,307		294,672
Mortgage-backed securities: commercial	17,445		17,695
Total	$	538,980	$	543,225

Securities pledged at March 31, 2020, and December 31, 2019 had a carrying amount of $287,371 and $294,585, respectively, that were pledged to secure public deposits.

At March 31, 2020 and December 31, 2019, there were no holdings of securities of any one issuer, other than the U.S. government-sponsored entities and agencies, in an amount greater than 10% of shareholders’ equity.

The following table summarizes the securities with unrealized and unrecognized losses at March 31, 2020 and December 31, 2019, aggregated by major security type and length of time in a continuous unrealized loss position:


	Less Than 12 Months						12 Months or Longer						Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
March 31, 2020
Available-for-sale
Mortgage-backed securities: residential	$	349	$	(3)	$	1,246	$	(1)	$	1,595	$	(4)
Mortgage-backed securities: commercial	—		—		3,193		(86)		3,193		(86)
Corporate notes	1,915		(85)		—		—		1,915		(85)
State and political subdivisions	121,212		(7,840)		—		—		121,212		(7,840)
Total available-for-sale	$	123,476	$	(7,928)	$	4,439	$	(87)	$	127,915	$	(8,015)


	Less Than 12 Months						12 Months or Longer						Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
December 31, 2019
Available-for-sale
Mortgage-backed securities: residential	$	49,390	$	(172)	$	91,644	$	(684)	$	141,034	$	(856)
Asset-backed securities	4,436		(29)		7,286		(105)		11,722		(134)
Corporate notes	997		(3)		—		—		997		(3)
State and political subdivisions	29,843		(142)		—		—		29,843		(142)
Total available-for-sale	$	84,666	$	(346)	$	98,930	$	(789)	$	183,596	$	(1,135)

Unrealized losses on debt securities have not been recognized into income because the issuers’ bonds are of high credit quality. As of March 31, 2020, management does not intend to sell and it is more likely than not that management will not be required to sell the securities prior to their anticipated recovery, and the decline in fair value is largely due to changes in interest rates and other market conditions. The fair value is expected to recover as the bonds approach maturity.