INVESTMENT SECURITIES

The following tables detail the amortized cost and the estimated fair value of our available-for-sale and held-to-maturity investment securities. None of our investment securities are classified as trading.



(Dollars in thousands)	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss		Fair Value
Available-for-Sale Securities:
March 31, 2017
GSE	$	33,051	$	2	$	72	$	32,981
CMO	280,576		699		3,564		277,711
FNMA MBS	393,356		984		8,289		386,051
FHLMC MBS	65,228		204		1,261		64,171
GNMA MBS	27,767		275		445		27,597
Other investments	634		—		20		614
	$	800,612	$	2,164	$	13,651	$	789,125
December 31, 2016
GSE	$	35,061	$	9	$	60	$	35,010
CMO	264,607		566		3,957		261,216
FNMA MBS	414,218		950		9,404		405,764
FHLMC MBS	64,709		135		1,330		63,514
GNMA MBS	28,540		303		427		28,416
Other investments	626		—		3		623
	$	807,761	$	1,963	$	15,181	$	794,543



(Dollars in thousands)	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss		Fair Value
Held-to-Maturity Securities⁽¹⁾
March 31, 2017
State and political subdivisions	$	163,611	$	646	$	1,016	$	163,241
December 31, 2016
State and political subdivisions	$	164,346	$	271	$	1,385	$	163,232

⁽¹⁾

Held-to–maturity securities transferred from available-for-sale are included in held-to-maturity at fair value at the time of transfer. The amortized cost of held-to-maturity securities included net unrealized gains of $2.1 million and $2.2 million at March 31, 2017 and December 31, 2016, respectively, related to securities transferred, which are offset in Accumulated Other Comprehensive Income, net of tax.

The scheduled maturities of investment securities available for sale and held to maturity at March 31, 2017 and December 31, 2016 are presented in the table below:



	Available for Sale ^{(1) (2)}
	Amortized		Fair
(Dollars in thousands)	Cost		Value
March 31, 2017
Within one year	$	20,012	$	19,997
After one year but within five years	18,059		17,981
After five years but within ten years	210,595		205,242
After ten years	551,312		545,291
	$	799,978	$	788,511
December 31, 2016
Within one year	$	16,009	$	16,017
After one year but within five years	19,052		18,992
After five years but within ten years	276,635		270,300
After ten years	495,439		488,611
	$	807,135	$	793,920

	Held to Maturity ⁽²⁾
	Amortized		Fair
(Dollars in thousands)	Cost		Value
March 31, 2017
Within one year	$	—	$	—
After one year but within five years	5,940		5,975
After five years but within ten years	10,482		10,511
After ten years	147,189		146,755
	$	163,611	$	163,241
December 31, 2016
Within one year	$	—	$	—
After one year but within five years	6,168		6,162
After five years but within ten years	8,882		8,870
After ten years	149,296		148,200
	$	164,346	$	163,232

⁽¹⁾ Included in the investment portfolio, but not in the table above, is a mutual fund with an amortized cost and fair value of $0.6 million as of March 31, 2017 and December 31, 2016 which has no stated maturity.


⁽²⁾	Actual maturities could differ

Mortgage-backed securities (MBS) have expected maturities that differ from their contractual maturities. These differences arise because borrowers have the right to call or prepay obligations with or without a prepayment penalty.

Investment securities with fair market values aggregating $615.8 million and $562.5 million were pledged as collateral for retail customer repurchase agreements, municipal deposits, and other obligations as of March 31, 2017 and December 31, 2016, respectively.

During the first three months of 2017, we sold $263.0 million of investment securities categorized as available for sale, resulting in realized gains of $0.3 million and one security with an immaterial realized loss. During the first three months of 2016, we sold $38.9 million of investment securities categorized as available for sale, resulting in realized gains of $0.3 million and no realized losses. The cost basis of all investment securities sales is based on the specific identification method.

As of March 31, 2017 and December 31, 2016, our investment securities portfolio had remaining unamortized premiums of $16.3 million and $18.0 million, respectively, and unaccreted discounts of $0.6 million and $0.4 million, respectively.

For investment securities with unrealized losses, the table below shows our gross unrealized losses and fair value by investment category and length of time that individual securities were in a continuous unrealized loss position at March 31, 2017.



	Duration of Unrealized Loss Position
	Less than 12 months				12 months or longer				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
(Dollars in thousands)	Value		Loss		Value		Loss		Value		Loss
Available-for-sale securities:
GSE	$	25,981	$	72	$	—	$	—	$	25,981	$	72
CMO	161,225		3,469		4,239		95		165,464		3,564
FNMA MBS	276,175		8,289		—		—		276,175		8,289
FHLMC MBS	41,765		1,261		—		—		41,765		1,261
GNMA MBS	16,236		445		—		—		16,236		445
Other investments	634		20		—		—		634		20
Total temporarily impaired investments	522,016		13,556		4,239		95		526,255		13,651

	Less than 12 months				12 months or longer				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
(Dollars in thousands)	Value		Loss		Value		Loss		Value		Loss
Held-to-maturity securities:
State and political subdivisions	$	84,121	$	969	$	1,960	$	47	$	86,081	$	1,016
Total temporarily impaired investments	$	84,121	$	969	$	1,960	$	47	$	86,081	$	1,016



	Duration of Unrealized Loss Position
	Less than 12 months				12 months or longer				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
(Dollars in thousands)	Value		Loss		Value		Loss		Value		Loss
Available-for-sale securities:
GSE	$	21,996	$	60	$	—	$	—	$	21,996	$	60
CMO	160,572		3,867		4,654		90		165,226		3,957
FNMA MBS	50,878		1,330		—		—		50,878		1,330
FHLMC MBS	300,403		9,404		—		—		300,403		9,404
GNMA MBS	16,480		427		—		—		16,480		427
Other investments	623		3		—		—		623		3
Total temporarily impaired investments	$	550,952	$	15,091	$	4,654	$	90	$	555,606	$	15,181

	Less than 12 months				12 months or longer				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
(Dollars in thousands)	Value		Loss		Value		Loss		Value		Loss
Held-to-maturity securities:
State and political subdivisions	$	112,642	$	1,374	$	695	$	11	$	113,337	$	1,385
Total temporarily impaired investments	$	112,642	$	1,374	$	695	$	11	$	113,337	$	1,385

At March 31, 2017, we owned investment securities totaling $612.3 million for which the amortized cost basis exceeded fair value. Total unrealized losses on these securities were $14.7 million at March 31, 2017. The temporary impairment is the result of changes in market interest rates subsequent to the purchase of the securities. Our investment portfolio is reviewed each quarter for indications of OTTI. This review includes analyzing the length of time and the extent to which the fair value has been lower than the amortized cost, the financial condition and near-term prospects of the issuer, including any specific events which may influence the operations of the issuer and our intent and ability to hold the investment for a period of time sufficient to allow for full recovery of the unrealized loss. We evaluate our intent and ability to hold securities based upon our investment strategy for the particular type of security and our cash flow needs, liquidity position, capital adequacy and interest rate risk position. We do not have the intent to sell, nor is it more likely-than-not we will be required to sell these securities before we are able to recover the amortized cost basis.

All securities, with the exception of one having a fair value of $1.0 million at March 31, 2017, were AA-rated or better at the time of purchase and remained investment grade at March 31, 2017. All securities were evaluated for OTTI at March 31, 2017 and December 31, 2016. The result of this evaluation showed no OTTI as of March 31, 2017 or December 31, 2016. The estimated weighted average duration of MBS was 5.34 years at March 31, 2017.