Note (3)—Investment securities:

The amortized cost of securities and their fair values at March 31, 2017 and December 31, 2016 are shown below:

	March 31, 2017
	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair Value
Securities Available-for-Sale
Debt securities
U.S. government agency securities	$	999	$	—	$	(12	)	$	987
Mortgage-backed securities - residential		432,499		824		(7,380	)		425,943
Municipals, tax exempt		119,182		3,149		(1,771	)		120,560
Treasury securities		11,817		—		(44	)		11,773
Total debt securities		564,497		3,973		(9,207	)		559,263
Equity securities		8,762		1		(140	)		8,623
Total securities available-for-sale	$	573,259	$	3,974	$	(9,347	)	$	567,886

	December 31, 2016
	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair Value
Securities Available-for-Sale
Debt securities
U.S. government agency securities	$	998	$	—	$	(13	)	$	985
Mortgage-backed securities - residential		450,874		939		(7,905	)		443,908
Municipals, tax exempt		116,034		3,003		(2,114	)		116,923
Treasury securities		11,809		—		(52	)		11,757
Total debt securities		579,715		3,942		(10,084	)		573,573
Equity securities		8,744		1		(135	)		8,610
Total securities available-for-sale	$	588,459	$	3,943	$	(10,219	)	$	582,183

Securities pledged at March 31, 2017 and December 31, 2016 had a carrying amount of $401,409 and $390,814, respectively, and were pledged to secure Federal Home Loan Bank advances, a Federal Reserve Bank line of credit, public deposits and repurchase agreements.

The amortized cost and fair value of debt securities by contractual maturity at March 31, 2017 and December 31, 2016 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, 2017				December 31, 2016
	Available-for-sale				Available-for-sale
	Amortized cost		Fair value		Amortized cost		Fair value
Due in one year or less	$	11,332	$	11,429	$	9,290	$	9,352
Due in one to five		28,982		30,069		25,520		26,340
Due in five to ten years		27,447		28,486		31,122		32,248
Due in over ten years		64,237		63,336		62,909		61,725
		131,998		133,320		128,841		129,665
Mortgage-backed securities - residential		432,499		425,943		450,874		443,908
	$	564,497	$	559,263	$	579,715	$	573,573

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

	Three Months Ended March 31,
	2017		2016
Proceeds from sales	$	—	$	102,263
Gross realized gains		—		1,400
Gross realized losses		—		—

The Company also recognized $1 in gains related to the early call of available-for-sale securities for the three months ended March 31, 2017.

Subsequent to March 31, 2017, the Company sold $12,135 in available-for-sale securities and recognized a gain of $23 related to this transaction.

The following tables show gross unrealized losses at March 31, 2017 and December 31, 2016, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position:

	March 31, 2017
	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	$	987	$	12	$	—	$	—	$	987	$	12
Mortgage-backed securities - residential		376,680		6,730		18,307		650		394,987		7,380
Municipals, tax exempt		40,529		1,757		216		14		40,745		1,771
Treasury securities		11,773		44		—		—		11,773	$	44
Total debt securities		429,969		8,543		18,523		664		448,492		9,207
Equity securities		—		—		3,005		140		3,005		140
	$	429,969	$	8,543	$	21,528	$	804	$	451,497	$	9,347

	December 31, 2016
	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	$	985	$	13	$	—	$	—	$	985	$	13
Mortgage-backed securities - residential		390,595		7,230		19,073		675		409,668		7,905
Municipals, tax exempt		43,132		2,114		—		—		43,132		2,114
Treasury securities		10,256		52		—		—		10,256		52
Total debt securities		444,968		9,409		19,073		675		464,041		10,084
Equity securities		—		—		3,126		135		3,126		135
	$	444,968	$	9,409	$	22,199	$	810	$	467,167	$	10,219

As of March 31, 2017 and December 31, 2016, the Company’s securities portfolio consisted of 335 and 329 securities, 143 and 151 of which were in an unrealized loss position, respectively.

The Company evaluates securities with unrealized losses for other-than-temporary impairment (OTTI), and the Company recorded no OTTI for the three months ended March 31, 2017 and 2016. 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. For debt 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 bases, which may be maturity. For equity securities, the Company has evaluated the near-term prospects of the investment in relation to the severity and duration of the impairment and based on that evaluation has the ability and intent to hold these investments until a recovery of fair value.