Securities (Tables)

6 Months Ended

Jun. 30, 2018

Investments, Debt and Equity Securities [Abstract]

Schedule of Fair Value and Amortized Cost of Available-for-sale and Held-to-maturity Debt Securities

The following table presents the fair value and amortized cost of available-for-sale and held-to-maturity debt securities:


	June 30, 2018									December 31, 2017
*(unaudited, in thousands)*	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Available-for-sale debt securities
U.S. Treasury	$	9,926	$	—	$	(13	)	$	9,913	$	—	$	—	$	—		$	—
U.S. Government sponsored entities and agencies		103,152		—		(2,470	)		100,682		72,425		24		(606	)		71,843
Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies		1,413,937		98		(40,618	)		1,373,417		954,115		214		(19,407	)		934,922
Commerical mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies		145,104		55		(4,512	)		140,647		116,448		4		(1,585	)		114,867
Obligations of states and political subdivisions		126,143		1,866		(1,210	)		126,799		102,363		2,927		(460	)		104,830
Corporate debt securities		45,070		211		(168	)		45,113		35,234		228		(59	)		35,403

Total available-for-sale debt securities	$	1,843,332	$	2,230	$	(48,991	)	$	1,796,571	$	1,280,585	$	3,397	$	(22,117	)	$	1,261,865

Held-to-maturity debt securities
U.S. Government sponsored entities and agencies	$	11,877	$	—	$	(390	)	$	11,487	$	11,465	$	—	$	(325	)	$	11,140
Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies		161,090		203		(5,740	)		155,553		170,025		544		(2,609	)		167,960
Obligations of states and political subdivisions		813,456		9,017		(6,065	)		816,408		794,655		17,364		(1,609	)		810,410
Corporate debt securities		33,323		4		(664	)		32,663		33,355		919		—			34,274

Total held-to-maturity debt securities	$	1,019,746	$	9,224	$	(12,859	)	$	1,016,111	$	1,009,500	$	18,827	$	(4,543	)	$	1,023,784

Total debt securities	$	2,863,078	$	11,454	$	(61,850	)	$	2,812,682	$	2,290,085	$	22,224	$	(26,660	)	$	2,285,649

Schedule of Fair Value of Available-for-sale and Held-to-maturity Debt Securities by Contractual Maturity

The following table presents the fair value of available-for-sale and held-to-maturity debt securities by contractual maturity at June 30, 2018. In some instances, the issuers may have the right to call or prepay obligations without penalty prior to the contractual maturity date.

June 30, 2018

(unaudited, in thousands)

One Year
or less

One to
Five Years

Five to
Ten Years

After
Ten Years

Mortgage-backed
securities

Total

Available-for-sale debt securities

U.S. Treasury

9,913

—

9,913

U.S. Government sponsored entities and agencies

10,459

6,302

13,739

6,802

63,380

100,682

Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies ⁽¹⁾

—

1,373,417

Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies ⁽¹⁾

—

140,647

Obligations of states and political subdivisions

9,629

23,831

51,042

42,297

—

126,799

Corporate debt securities

9,801

33,364

1,948

—

45,113

Total available-for-sale debt securities

39,802

63,497

66,729

49,099

1,577,444

1,796,571

Held-to-maturity debt securities ⁽²⁾

U.S. Government sponsored entities and agencies

—

11,487

Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies ⁽¹⁾

—

155,553

Obligations of states and political subdivisions

6,410

123,247

393,073

293,678

816,408

Corporate debt securities

—

7,448

25,215

—

32,663

Total held-to-maturity debt securities

6,410

130,695

418,288

293,678

167,040

1,016,111

Total debt securities

46,212

194,192

485,017

342,777

1,744,484

2,812,682

⁽¹⁾	Mortgage-backed and collateralized mortgage securities, which have prepayment provisions, are not assigned to maturity categories due to fluctuations in their prepayment speeds.

⁽²⁾	The held-to-maturity debt securities portfolio is carried at an amortized cost of $1.0 billion.

Schedule of Gross Realized Gains and Losses on the Sales and Calls of Securities as well as Gains and Losses on Equity Securities

The following table presents the gross realized gains and losses on sales and calls of available-for-sale and held-to-maturity debt securities, as well as gains and losses on equity securities for the three and six months ended June 30, 2018 and 2017, respectively.


	For the Three Months Ended June 30,					For the Six Months Ended June 30,
*(unaudited, in thousands)*	2018		2017			2018			2017
Debt securities:
Gross realized gains	$	5	$	562		$	12		$	574
Gross realized losses		—		(68	)		(18	)		(68	)

Net gains (losses) on debt securities	$	5	$	494		$	(6	)	$	506

Equity securities:
Unrealized gains recognized on securities still held	$	347	$	—		$	319		$	—
Net realized gains recognized on securities sold		6		—			6			—

Net gains on equity securities	$	353	$	—		$	325		$	—

Net securities gains	$	358	$	494		$	319		$	506

Schedule of Unrealized Losses on Debt Securities

The following tables provide information on unrealized losses on debt securities that have been in an unrealized loss position for less than twelve months and twelve months or more as of June 30, 2018 and December 31, 2017:


	June 30, 2018
	Less than 12 months							12 months or more							Total
	Fair		Unrealized			# of		Fair		Unrealized			# of		Fair		Unrealized			# of
*(unaudited, dollars in thousands)*	Value		Losses			Securities		Value		Losses			Securities		Value		Losses			Securities
U.S. Treasury	$	9,913	$	(13	)		1	$	—	$	—			—	$	9,913	$	(13	)		1
U.S. Government sponsored entities and agencies		71,179		(1,885	)		23		40,491		(975	)		8		111,670		(2,860	)		31
Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies		864,036		(16,625	)		160		610,641		(29,733	)		201		1,474,677		(46,358	)		361
Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies		104,546		(3,531	)		13		23,225		(981	)		4		127,771		(4,512	)		17
Obligations of states and political subdivisions		357,070		(5,019	)		571		76,447		(2,256	)		163		433,517		(7,275	)		734
Corporate debt securities		43,559		(791	)		21		1,948		(41	)		1		45,507		(832	)		22

Total temporarily impaired securities	$	1,450,303	$	(27,864	)		789	$	752,752	$	(33,986	)		377	$	2,203,055	$	(61,850	)		1,166


	December 31, 2017
	Less than 12 months							12 months or more							Total
	Fair		Unrealized			# of		Fair		Unrealized			# of		Fair		Unrealized			# of
*(unaudited, dollars in thousands)*	Value		Losses			Securities		Value		Losses			Securities		Value		Losses			Securities
U.S. Government sponsored entities and agencies	$	24,776	$	(160	)		4	$	42,248	$	(771	)		8	$	67,024	$	(931	)		12
Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies		423,794		(5,039	)		87		637,461		(16,977	)		193		1,061,255		(22,016	)		280
Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies		79,061		(1,089	)		10		27,852		(496	)		6		106,913		(1,585	)		16
Obligations of states and political subdivisions		132,831		(852	)		210		77,554		(1,217	)		160		210,385		(2,069	)		370
Corporate debt securities		4,015		(19	)		1		1,948		(40	)		1		5,963		(59	)		2

Total temporarily impaired securities	$	664,477	$	(7,159	)		312	$	787,063	$	(19,501	)		368	$	1,451,540	$	(26,660	)		680