Investment Securities (Tables)

9 Months Ended

Sep. 30, 2017

Investments, Debt and Equity Securities [Abstract]

Schedule of Amortized Cost and Estimated Fair Value of Available-for-Sale and Held-to-Maturity 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:
September 30, 2017
CMO	$	269,267	$	895	$	2,354	$	267,808
FNMA MBS	434,920		1,545		5,223		431,242
FHLMC MBS	85,564		277		779		85,062
GNMA MBS	25,723		289		315		25,697
Other investments	640		—		16		624
	$	816,114	$	3,006	$	8,687	$	810,433
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⁾
September 30, 2017
State and political subdivisions	$	161,721	$	1,796	$	120	$	163,397
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 $1.8 million and $2.2 million at September 30, 2017 and December 31, 2016, respectively, related to securities transferred, which are offset in Accumulated Other Comprehensive Income, net of tax

Schedule of Maturities of Investment Securities Available-for-Sale and Held-to-Maturity

The scheduled maturities of investment securities available for sale and held to maturity at September 30, 2017 and December 31, 2016 are presented in the table below:



	Available for Sale ⁽¹⁾
	Amortized		Fair
(Dollars in thousands)	Cost		Value
September 30, 2017
Within one year	$	—	$	—
After one year but within five years	4,007		4,002
After five years but within ten years	201,919		198,334
After ten years	609,548		607,473
	$	815,474	$	809,809
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
	Amortized		Fair
(Dollars in thousands)	Cost		Value
September 30, 2017
Within one year	$	328	$	326
After one year but within five years	5,437		5,491
After five years but within ten years	15,672		15,838
After ten years	140,284		141,742
	$	161,721	$	163,397
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 and $0.6 million as of September 30, 2017 and December 31, 2016 which has no stated maturity.

Schedule of Investment Securities' Gross Unrealized Losses and Fair Value by Investment Category

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 September 30, 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:
CMO	$	114,939	$	1,188	$	43,775	$	1,166	$	158,714	$	2,354
FNMA MBS	188,153		2,299		74,801		2,924		262,954		5,223
FHLMC MBS	45,317		497		7,892		282		53,209		779
GNMA MBS	4,856		83		10,687		232		15,543		315
Other investments	—		—		624		16		624		16
Total temporarily impaired investments	$	353,265	$	4,067	$	137,779	$	4,620	$	491,044	$	8,687

	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	$	13,571	$	48	$	6,700	$	72	$	20,271	$	120
Total temporarily impaired investments	$	13,571	$	48	$	6,700	$	72	$	20,271	$	120



	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