Securities (Tables)

9 Months Ended

Sep. 30, 2019

Investments Debt And Equity Securities [Abstract]

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

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

	September 30, 2019									December 31, 2018
(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	$	29,817	$	61	$	—		$	29,878	$	19,882	$	3	$	(7	)	$	19,878
U.S. Government sponsored entities and agencies		116,508		4,012		(79	)		120,441		142,852		556		(1,756	)		141,652
Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies		1,663,942		21,469		(4,346	)		1,681,065		1,585,864		2,912		(27,521	)		1,561,255
Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies		183,634		4,716		(45	)		188,305		171,671		264		(2,963	)		168,972
Obligations of states and political subdivisions		145,593		5,771		(1	)		151,363		184,057		2,039		(982	)		185,114
Corporate debt securities		37,684		592		(129	)		38,147		37,730		87		(559	)		37,258
Total available-for-sale debt securities	$	2,177,178	$	36,621	$	(4,600	)	$	2,209,199	$	2,142,056	$	5,861	$	(33,788	)	$	2,114,129
Held-to-maturity debt securities
U.S. Government sponsored entities and agencies	$	9,854	$	53	$	(46	)	$	9,861	$	10,823	$	6	$	(329	)	$	10,500
Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies		129,797		1,273		(155	)		130,915		148,300		204		(4,170	)		144,334
Obligations of states and political subdivisions		679,932		22,244		(170	)		702,006		828,520		8,771		(4,012	)		833,279
Corporate debt securities		33,241		1,786		—			35,027		33,291		12		(673	)		32,630
Total held-to-maturity debt securities	$	852,824	$	25,356	$	(371	)	$	877,809	$	1,020,934	$	8,993	$	(9,184	)	$	1,020,743
Total debt securities	$	3,030,002	$	61,977	$	(4,971	)	$	3,087,008	$	3,162,990	$	14,854	$	(42,972	)	$	3,134,872

Schedule of Amortized Cost and Fair Value of Available-for-Sale and Held-to-Maturity Securities by Contractual Maturity

The following table presents the amortized cost and fair value of available-for-sale and held-to-maturity debt securities by contractual maturity date at September 30, 2019. Actual maturities will differ from contractual maturities because borrowers may have the right to call or prepay debt obligations with or without prepayment penalties. Mortgage-backed securities and collateralized mortgage obligations are classified in the table below based on their contractual maturity date; however, principal payments are received on a monthly basis.

(unaudited, in thousands)	Amortized Cost		Fair Value
Available-for-sale debt securities
Less than one year	$	61,932	$	61,992
1-5 years		116,281		117,740
5-10 years		407,897		416,454
Over 10 years		1,591,068		1,613,013
Total available-for-sale debt securities	$	2,177,178	$	2,209,199
Held-to-maturity debt securities
Less than one year	$	18,138	$	18,201
1-5 years		127,140		130,634
5-10 years		328,315		338,075
Over 10 years		379,231		390,899
Total held-to-maturity debt securities	$	852,824	$	877,809
Total debt securities	$	3,030,002	$	3,087,008

Schedule of Gross Realized Gains and Losses on the Sales and Calls of 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 from both sales and market adjustments from the adoption of ASU 2016-01 effective January 1, 2018, for the three and nine months ended September 30, 2019 and 2018, respectively.

	For the Three Months Ended September 30,						For the Nine Months Ended September 30,
(unaudited, in thousands)	2019			2018			2019			2018
Debt securities:
Gross realized gains	$	1,096		$	88		$	1,443		$	100
Gross realized losses		(741	)		(13	)		(950	)		(31	)
Net gains (losses) on debt securities	$	355		$	75		$	493		$	69
Equity securities:
Net unrealized gains (losses) recognized on securities still held	$	(120	)	$	11		$	748		$	330
Net realized gains (losses) recognized on securities sold		—			(2	)		2,559			4
Net gains (losses) on equity securities	$	(120	)	$	9		$	3,307		$	334
Net securities gains	$	235		$	84		$	3,800		$	403

Schedule of Unrealized Losses on Investment 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 September 30, 2019 and December 31, 2018, respectively:

	September 30, 2019
	Less than 12 months							12 months or more							Total
(unaudited, dollars in thousands)	Fair Value		Unrealized Losses			# of Securities		Fair Value		Unrealized Losses			# of Securities		Fair Value		Unrealized Losses			# of Securities
U.S. Government sponsored entities and agencies	$	5,383	$	(17	)		4	$	6,781	$	(108	)		2	$	12,164	$	(125	)		6
Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies		347,848		(1,515	)		70		306,696		(2,986	)		128		654,544		(4,501	)		198
Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies		11,066		(38	)		3		3,729		(7	)		2		14,795		(45	)		5
Obligations of states and political subdivisions		12,650		(39	)		21		7,581		(132	)		17		20,231		(171	)		38
Corporate debt securities		—		—			—		7,896		(129	)		3		7,896		(129	)		3
Total temporarily impaired securities	$	376,947	$	(1,609	)		98	$	332,683	$	(3,362	)		152	$	709,630	$	(4,971	)	$	250

	December 31, 2018
	Less than 12 months							12 months or more							Total
(unaudited, dollars in thousands)	Fair Value		Unrealized Losses			# of Securities		Fair Value		Unrealized Losses			# of Securities		Fair Value		Unrealized Losses			# of Securities
U.S. Treasury	$	9,972	$	(7	)		1	$	—	$	—			—	$	9,972	$	(7	)		1
U.S. Government sponsored entities and agencies		18,926		(148	)		8		76,385		(1,937	)		14		95,311		(2,085	)		22
Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies		285,534		(1,862	)		44		922,698		(29,829	)		291		1,208,232		(31,691	)		335
Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies		9,186		(18	)		6		111,068		(2,945	)		14		120,254		(2,963	)		20
Obligations of states and political subdivisions		104,469		(439	)		207		303,681		(4,555	)		513		408,150		(4,994	)		720
Corporate debt securities		38,791		(898	)		18		11,452		(334	)		5		50,243		(1,232	)		23
Total temporarily impaired securities	$	466,878	$	(3,372	)		284	$	1,425,284	$	(39,600	)		837	$	1,892,162	$	(42,972	)		1,121