Investment securities:

The amortized cost of securities and their fair values at March 31, 2019 and December 31, 2018 are shown below:



	March 31, 2019
	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair Value
Investment Securities
Available-for-sale debt securities
U.S. government agency securities	$	1,000	$	—	$	(7	)	$	993
Mortgage-backed securities - residential	516,917		2,407		(7,608		)	511,716
Municipals, tax exempt	144,142		3,904		(406		)	147,640
Treasury securities	7,394		—		(89		)	7,305
Total	$	669,453	$	6,311	$	(8,110	)	$	667,654



	December 31, 2018
	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair Value
Investment Securities
Available-for-sale debt securities
U.S. government agency securities	$	1,000	$	—	$	(11	)	$	989
Mortgage-backed securities - residential	520,654		1,191		(13,265		)	508,580
Municipals, tax exempt	138,994		1,565		(1,672		)	138,887
Treasury securities	7,385		—		(143		)	7,242
Total	$	668,033	$	2,756	$	(15,091	)	$	655,698

As of March 31, 2019 and December 31, 2018, the Company had $3,181 and $3,107 in marketable equity securities recorded at fair value, respectively.

Securities pledged at March 31, 2019 and December 31, 2018 had carrying amounts of $330,966 and $326,215, respectively, and were pledged to secure a Federal Reserve Bank line of credit, public deposits and repurchase agreements.

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 shareholders' equity during any period presented.

Included in available-for-sale securities at March 31, 2019 and December 31, 2018 were $2,524 and $2,120, respectively, in trade date payables that were settled after period end.

The amortized cost and fair value of debt securities by contractual maturity at March 31, 2019 and December 31, 2018 are shown below. Maturities may differ from contractual maturities in mortgage-backed securities because the mortgage underlying the security may be called or repaid without any penalties. Therefore, mortgage-backed securities are not included in the maturity categories in the following maturity summary.



	March 31, 2019				December 31, 2018
	Available-for-sale				Available-for-sale
	Amortized cost		Fair value		Amortized cost		Fair value
Due in one year or less	$	11,682	$	11,772	$	15,883	$	16,028
Due in one to five years	13,498		13,506		13,806		13,740
Due in five to ten years	16,891		16,974		18,539		18,387
Due in over ten years	110,465		113,686		99,151		98,963
	152,536		155,938		147,379		147,118
Mortgage-backed securities - residential	516,917		511,716		520,654		508,580
Total debt securities	$	669,453	$	667,654	$	668,033	$	655,698

Sales of available-for-sale securities were as follows:



	Three Months Ended March 31,
	2019		2018
Proceeds from sales	$	1,758	$	221
Gross realized gains	1		—
Gross realized losses	7		9

Additionally, net gains of $49 and net losses of $38 were recognized due to changes in fair value of these securities during the three months ended March 31, 2019 and 2018, respectively.

The following tables show gross unrealized losses at March 31, 2019 and December 31, 2018, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position:



	March 31, 2019
	Less than 12 months					12 months or more					Total
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss			Fair Value		Unrealized loss
U.S. government agency securities	$	—	$	—		$	993	$	(7	)	$	993	$	(7	)
Mortgage-backed securities - residential	4,913		(10		)	357,430		(7,598		)	362,343		(7,608		)
Municipals, tax exempt	—		—			21,580		(406		)	21,580		(406		)
Treasury securities	—		—			7,305		(89		)	7,305		(89		)
Total	$	4,913	$	(10	)	$	387,308	$	(8,100	)	$	392,221	$	(8,110	)



	December 31, 2018
	Less than 12 months					12 months or more					Total
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss			Fair Value		Unrealized loss
U.S. government agency securities	$	—	$	—		$	989	$	(11	)	$	989	$	(11	)
Mortgage-backed securities - residential	60,347		(478		)	335,769		(12,787		)	396,116		(13,265		)
Municipals, tax exempt	27,511		(366		)	25,343		(1,306		)	52,854		(1,672		)
Treasury securities	—		—			7,242		(143		)	7,242		(143		)
Total	$	87,858	$	(844	)	$	369,343	$	(14,247	)	$	457,201	$	(15,091	)

As of March 31, 2019 and December 31, 2018, the Company’s securities portfolio consisted of 353 and 360 securities, 116 and 174 of which were in an unrealized loss position, respectively.

The Company evaluates available-for-sale debt securities with unrealized losses for other-than-temporary impairment (OTTI) on a quarterly basis and recorded no OTTI for the three months ended March 31, 2019 and 2018. The Company considers an investment security impaired if the fair value of the security is less than its cost or amortized cost basis. For debt securities, the unrealized losses associated with these investment securities are primarily driven by interest rates and are not due to the credit quality of the securities. The Company currently does not intend to sell those investments with unrealized losses, and it is unlikely that the Company will be required to sell the investments before recovery of their amortized cost basis, which may be maturity.