(3)	SECURITIES

The following table summarizes securities held for investment and securities available for sale:

	June 30, 2018		December 31, 2017
	(Dollars in thousands)
Held for investment, at cost (fair value: $2,017 and $2,303, respectively)	$	2,008	$	2,292
Available for sale, at fair value		460,863		467,703
Total	$	462,871	$	469,995

The following table summarizes the amortized cost and estimated fair values of securities held for investment:


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
June 30, 2018	(Dollars in thousands)
Mortgage backed securities (1)	$	158	$	6	$	—		$	164
States and political subdivisions		1,350		3		—			1,353
Other securities		500		—		—			500
Total	$	2,008	$	9	$	—		$	2,017
December 31, 2017
Mortgage backed securities (1)	$	187	$	10	$	—		$	197
States and political subdivisions		1,605		3		(2	)		1,606
Other securities		500		—		—			500
Total	$	2,292	$	13	$	(2	)	$	2,303

The following table summarizes the amortized cost and estimated fair values of securities available for sale:


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
June 30, 2018	(Dollars in thousands)
U.S. treasuries	$	324,661	$	108	$	(4,574	)	$	320,195
U.S. federal agencies		84,649		2		(222	)		84,429
Mortgage backed securities (1)		16,828		137		(559	)		16,406
States and political subdivisions		39,606		347		(120	)		39,833
Total	$	465,744	$	594	$	(5,475	)	$	460,863
December 31, 2017
U.S. treasuries	$	314,905	$	—	$	(2,103	)	$	312,802
U.S. federal agencies		89,098		82		(329	)		88,851
Mortgage backed securities (1)		18,358		204		(586	)		17,976
States and political subdivisions		41,937		554		(121	)		42,370
Equity securities (2)		6,527		71		(894	)		5,704
Total	$	470,825	$	911	$	(4,033	)	$	467,703

(1)

Primarily consists of FHLMC, FNMA, GNMA and mortgage backed securities through U.S. agencies.

(2)

Consisted of equity securities that are included in other assets in 2018.

The maturities of securities held for investment and available for sale are summarized in the following table using contractual maturities. Actual maturities may differ from contractual maturities due to obligations that are called or prepaid. For purposes of the maturity table, mortgage-backed securities, which are not due at a single maturity date, have been presented at their contractual maturity.

	June 30, 2018				December 31, 2017
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
	(Dollars in thousands)
Held for Investment
Contractual maturity of debt securities:
Within one year	$	975	$	978	$	1,036	$	1,034
After one year but within five years		428		428		623		627
After five years but within ten years		599		605		625		633
After ten years		6		6		8		9
Total	$	2,008	$	2,017	$	2,292	$	2,303
Available for Sale
Contractual maturity of debt securities:
Within one year	$	114,086	$	113,828	$	113,225	$	112,974
After one year but within five years		296,057		291,843		289,038		287,058
After five years but within ten years		6,129		6,306		6,222		6,500
After ten years		49,472		48,886		55,813		55,467
Total debt securities		465,744		460,863		464,298		461,999
Equity securities		—		—		6,527		5,704
Total	$	465,744	$	460,863	$	470,825	$	467,703

The following table is a summary of the Company’s book value of securities that were pledged as collateral for public funds on deposit, repurchase agreements and for other purposes as required or permitted by law:

	June 30, 2018		December 31, 2017
	(Dollars in thousands)
Book value of pledged securities	$	439,030	$	440,069