Securities (Tables)

9 Months Ended

Sep. 30, 2024

Investments, Debt and Equity Securities [Abstract]

Schedule of Equity securities gains and losses [Table Text Block]

	Three Months Ended				Nine Months Ended
	September 30				September 30
	2024		2023		2024		2023
	Dollars in thousands
Net gains (losses) recognized during the period on equity securities	$	685	$	(363)	1,187		272
Less: net gains (losses) recognized during the period on equity securities sold during the period	81		(34)		519		(33)
Unrealized gains (losses) recognized during the reporting period on equity securities still held at the reporting date	$	604	$	(329)	$	668	$	305

Debt Securities, Available-for-sale [Table Text Block]

The following table summarizes the amortized cost, allowance for credit losses, and fair value of available for sale securities and the corresponding amounts of gross unrealized gains and losses recognized in accumulated other comprehensive income (loss) at the dates indicated:

	September 30, 2024										December 31, 2023
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Allowance for credit losses		Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Allowance for credit losses		Fair Value
	(Dollars in thousands)
U.S. government agency securities	$	229,642	$	—	$	(16,558)	$	—	$	213,084	$	230,198	$	—	$	(23,060)	$	—	$	207,138
U.S. treasury securities	674,920		—		(34,007)		—		640,913		824,597		—		(55,495)		—		769,102
Agency mortgage-backed securities	346,931		60		(29,282)		—		317,709		314,269		24		(37,246)		—		277,047
Agency collateralized mortgage obligations	32,277		8		(1,646)		—		30,639		35,713		6		(2,530)		—		33,189
State, county, and municipal securities	196		—		—		—		196		195		—		(5)		—		190
Pooled trust preferred securities issued by banks and insurers	1,180		—		(153)		—		1,027		1,188		—		(170)		—		1,018
Small business administration pooled securities	49,587		—		(5,944)		—		43,643		53,702		—		(7,130)		—		46,572
Total available for sale securities	$	1,334,733	$	68	$	(87,590)	$	—	$	1,247,211	$	1,459,862	$	30	$	(125,636)	$	—	$	1,334,256

Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value [Table Text Block]

These available for sale securities are aggregated by major security type and length of time that individual securities have been in a continuous unrealized loss position:

	September 30, 2024
		Less than 12 months				12 months or longer				Total
	# of  holdings	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
	(Dollars in thousands)
U.S. government agency securities	9	$	—	$	—	$	213,084	$	(16,558)	$	213,084	$	(16,558)
U.S. treasury securities	14	—		—		640,913		(34,007)		640,913		(34,007)
Agency mortgage-backed securities	104	47,479		(188)		266,901		(29,094)		314,380		(29,282)
Agency collateralized mortgage obligations	9	—		—		28,452		(1,646)		28,452		(1,646)
Pooled trust preferred securities issued by banks and insurers	1	—		—		1,027		(153)		1,027		(153)
Small business administration pooled securities	8	—		—		43,643		(5,944)		43,643		(5,944)
Total	145	$	47,479	$	(188)	$	1,194,020	$	(87,402)	$	1,241,499	$	(87,590)
	December 31, 2023
		Less than 12 months				12 months or longer				Total
	# of  holdings	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
	(Dollars in thousands)
U.S. government agency securities	9	$	—	$	—	$	207,138	$	(23,060)	$	207,138	$	(23,060)
U.S. treasury securities	17	—		—		769,102		(55,495)		769,102		(55,495)
Agency mortgage-backed securities	115	1,091		(11)		273,447		(37,235)		274,538		(37,246)
Agency collateralized mortgage obligations	12	339		(2)		31,682		(2,528)		32,021		(2,530)
State, county, and municipal securities	1	190		(5)		—		—		190		(5)
Pooled trust preferred securities issued by banks and insurers	1	—		—		1,018		(170)		1,018		(170)
Small business administration pooled securities	8	—		—		46,572		(7,130)		46,572		(7,130)
Total	163	$	1,620	$	(18)	$	1,328,959	$	(125,618)	$	1,330,579	$	(125,636)

Debt Securities, Held-to-maturity [Table Text Block]

The following table summarizes the amortized cost, fair value and allowance for credit losses of held to maturity securities and the corresponding amounts of gross unrealized gains and losses recognized at the dates indicated:

	September 30, 2024										December 31, 2023
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Allowance for credit losses		Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Allowance for credit losses		Fair Value
	(Dollars in thousands)
U.S. government agency securities	$	28,218	$	—	$	(156)	$	—	$	28,062	$	29,521	$	—	$	(1,113)	$	—	$	28,408
U.S. treasury securities	100,772		—		(6,582)		—		94,190		100,712		—		(9,177)		—		91,535
Agency mortgage-backed securities	798,919		644		(48,044)		—		751,519		829,431		175		(65,878)		—		763,728
Agency collateralized mortgage obligations	437,552		—		(57,209)		—		380,343		477,517		—		(69,606)		—		407,911
Single issuer trust preferred securities issued by banks	1,500		—		(49)		—		1,451		1,500		—		(127)		—		1,373
Small business administration pooled securities	125,354		482		(3,936)		—		121,900		130,426		384		(6,157)		—		124,653
Total held to maturity securities	$	1,492,315	$	1,126	$	(115,976)	$	—	$	1,377,465	$	1,569,107	$	559	$	(152,058)	$	—	$	1,417,608

Schedule of contractual maturities of securities [Table Text Block]

A schedule of the contractual maturities of securities available for sale and securities held to maturity at September 30, 2024 is presented below:

	Due in one year or less				Due after one year to five years				Due after five to ten years				Due after ten years				Total
	Amortized Cost		Fair Value		Amortized Cost		Fair Value		Amortized Cost		Fair Value		Amortized Cost		Fair Value		Amortized Cost		Fair Value
	(Dollars in thousands)
Available for sale securities
U.S. government agency securities	$	—	$	—	$	229,642	$	213,084	$	—	$	—	$	—	$	—	$	229,642	$	213,084
U.S. treasury securities	196,815		192,493		478,105		448,420		—		—		—		—		674,920		640,913
Agency mortgage-backed securities	16		16		139,183		128,734		71,034		66,751		136,698		122,208		346,931		317,709
Agency collateralized mortgage obligations	—		—		—		—		2,598		2,446		29,679		28,193		32,277		30,639
State, county, and municipal securities	—		—		196		196		—		—		—		—		196		196
Pooled trust preferred securities issued by banks and insurers	—		—		—		—		—		—		1,180		1,027		1,180		1,027
Small business administration pooled securities	—		—		—		—		—		—		49,587		43,643		49,587		43,643
Total available for sale securities	$	196,831	$	192,509	$	847,126	$	790,434	$	73,632	$	69,197	$	217,144	$	195,071	$	1,334,733	$	1,247,211
Held to maturity securities
U.S. government agency securities	$	28,218	$	28,062	$	—	$	—	$	—	$	—	$	—	$	—	$	28,218	$	28,062
U.S. treasury securities	—		—		99,779		93,334		993		856		—		—		100,772		94,190
Agency mortgage-backed securities	—		—		463,840		441,693		158,938		142,894		176,141		166,932		798,919		751,519
Agency collateralized mortgage obligations	—		—		63,176		60,049		17,779		16,183		356,597		304,111		437,552		380,343
Single issuer trust preferred securities issued by banks	—		—		1,500		1,451		—		—		—		—		1,500		1,451
Small business administration pooled securities	—		—		—		—		7,076		6,643		118,278		115,257		125,354		121,900
Total held to maturity securities	$	28,218	$	28,062	$	628,295	$	596,527	$	184,786	$	166,576	$	651,016	$	586,300	$	1,492,315	$	1,377,465
Total	$	225,049	$	220,571	$	1,475,421	$	1,386,961	$	258,418	$	235,773	$	868,160	$	781,371	$	2,827,048	$	2,624,676