INVESTMENTS (Tables)

9 Months Ended

Sep. 30, 2019

Investments, Debt and Equity Securities [Abstract]

Summary of Held-To-Maturity and Available-For-Sale Investment Securities

The following is a summary of HTM and AFS investment securities as of September 30, 2019:

	Held-to-maturity									Available-for-sale
(Dollars in thousands)	Amortized cost		Unrecognized gain		Unrecognized loss			Fair value		Amortized cost		Unrealized gain		Unrealized loss			Fair value
U.S. Treasuries	$	0	$	0	$	0		$	0	$	99	$	1	$	0		$	100
Securities of U.S. government agencies and corporations	0		0		0			0		156		3		0			159
Mortgage-backed securities - residential	22,367		184		(41		)	22,510		416,446		9,679		(103		)	426,022
Mortgage-backed securities - commercial	104,586		1,105		(828		)	104,863		440,457		6,929		(2,052		)	445,334
Collateralized mortgage obligations	10,545		0		(118		)	10,427		799,072		20,067		(208		)	818,931
Obligations of state and other political subdivisions	11,280		705		(61		)	11,924		588,634		25,140		(61		)	613,713
Asset-backed securities	0		0		0			0		465,542		1,652		(1,107		)	466,087
Other securities	0		0		0			0		78,745		1,654		(243		)	80,156
Total	$	148,778	$	1,994	$	(1,048	)	$	149,724	$	2,789,151	$	65,125	$	(3,774	)	$	2,850,502

The following is a summary of HTM and AFS investment securities as of December 31, 2018:

	Held-to-maturity									Available-for-sale
(Dollars in thousands)	Amortized cost		Unrecognized gain		Unrecognized loss			Fair value		Amortized cost		Unrealized gain		Unrealized loss			Fair value
U.S. Treasuries	$	0	$	0	$	0		$	0	$	99	$	0	$	(2	)	$	97
Securities of U.S. government agencies and corporations	0		0		0			0		32,095		57		(233		)	31,919
Mortgage-backed securities - residential	25,565		0		(1,045		)	24,520		565,071		691		(7,163		)	558,599
Mortgage-backed securities - commercial	147,780		258		(4,385		)	143,653		423,797		819		(3,581		)	421,035
Collateralized mortgage obligations	12,540		0		(633		)	11,907		928,586		4,319		(6,158		)	926,747
Obligations of state and other political subdivisions	243,443		1,954		(1,359		)	244,038		257,300		2,554		(1,429		)	258,425
Asset-backed securities	0		0		0			0		511,430		611		(2,810		)	509,231
Other securities	0		0		0			0		73,948		358		(1,104		)	73,202
Total	$	429,328	$	2,212	$	(7,422	)	$	424,118	$	2,792,326	$	9,409	$	(22,480	)	$	2,779,255

Summary of Investment Securities by Estimated Maturity

The following table provides a summary of investment securities by contractual maturity as of September 30, 2019, except for residential and commercial mortgage-backed securities, collateralized mortgage obligations and asset-backed securities, which are shown as single totals due to the unpredictability of the timing in principal repayments.

	Held-to-maturity				Available-for-sale
(Dollars in thousands)	Amortized cost		Fair value		Amortized cost		Fair value
By Contractual Maturity:
Due in one year or less	$	0	$	0	$	8,694	$	8,713
Due after one year through five years	0		0		48,276		49,127
Due after five years through ten years	4,321		4,830		147,357		152,333
Due after ten years	6,959		7,094		463,307		483,955
Mortgage-backed securities - residential	22,367		22,510		416,446		426,022
Mortgage-backed securities - commercial	104,586		104,863		440,457		445,334
Collateralized mortgage obligations	10,545		10,427		799,072		818,931
Asset-backed securities	0		0		465,542		466,087
Total	$	148,778	$	149,724	$	2,789,151	$	2,850,502

Age of Gross Unrealized Losses and Associated Fair Value by Investment Category

The following tables provide the fair value and gross unrealized losses on investment securities in an unrealized loss position, aggregated by investment category and the length of time the individual securities have been in a continuous loss position:

	September 30, 2019
	Less than 12 months					12 months or more					Total
(Dollars in thousands)	Fair value		Unrealized loss			Fair value		Unrealized loss			Fair value		Unrealized loss
U.S. Treasuries	$	0	$	0		$	0	$	0		$	0	$	0
Securities of U.S. Government agencies and corporations	0		0			0		0			0		0
Mortgage-backed securities - residential	14,365		(45		)	11,851		(99		)	26,216		(144		)
Mortgage-backed securities - commercial	52,281		(60		)	89,681		(2,820		)	141,962		(2,880		)
Collateralized mortgage obligations	43,732		(107		)	29,908		(219		)	73,640		(326		)
Obligations of state and other political subdivisions	14,202		(44		)	6,714		(78		)	20,916		(122		)
Asset-backed securities	259,681		(824		)	40,776		(283		)	300,457		(1,107		)
Other securities	4,160		(10		)	5,525		(233		)	9,685		(243		)
Total	$	388,421	$	(1,090	)	$	184,455	$	(3,732	)	$	572,876	$	(4,822	)

	December 31, 2018
	Less than 12 months					12 months or more					Total
	Fair		Unrealized			Fair		Unrealized			Fair		Unrealized
(Dollars in thousands)	value		loss			value		loss			value		loss
U.S. Treasuries	$	0	$	0		$	97	$	(2	)	$	97	$	(2	)
Securities of U.S. Government agencies and corporations	0		0			16,777		(233		)	16,777		(233		)
Mortgage-backed securities - residential	186,029		(935		)	264,795		(7,273		)	450,824		(8,208		)
Mortgage-backed securities - commercial	147,754		(369		)	232,363		(7,597		)	380,117		(7,966		)
Collateralized mortgage obligations	194,795		(1,546		)	240,514		(5,245		)	435,309		(6,791		)
Obligations of state and other political subdivisions	62,805		(299		)	86,644		(2,489		)	149,449		(2,788		)
Asset-backed securities	336,437		(2,312		)	37,105		(498		)	373,542		(2,810		)
Other securities	33,752		(884		)	4,570		(220		)	38,322		(1,104		)
Total	$	961,572	$	(6,345	)	$	882,865	$	(23,557	)	$	1,844,437	$	(29,902	)