Securities (Tables)

9 Months Ended

Sep. 30, 2024

Securities

Schedule of amortized cost and estimated fair value of securities

			Gross		Gross		Allowance		Estimated
	Amortized		Unrealized		Unrealized		for Credit		Fair
September 30, 2024	Cost		Gains		(Losses)		Losses		Value
	(Dollars in thousands)
Securities available-for-sale:
U.S. Treasury	$	185,602	$	—	$	(1,440)	$	—	$	184,162
Agency mortgage-backed securities		56,373		—		(2,923)		—		53,450
Total	$	241,975	$	—	$	(4,363)	$	—	$	237,612
			Gross		Gross		Estimated		Allowance
	Amortized		Unrecognized		Unrecognized		Fair		for Credit
September 30, 2024	Cost		Gains		(Losses)		Value		Losses
	(Dollars in thousands)
Securities held-to-maturity:
Agency mortgage-backed securities	$	573,621	$	381	$	(72,377)	$	501,625	$	—
Municipals - exempt from Federal tax		30,584		3		(679)		29,908		(12)
Total	$	604,205	$	384	$	(73,056)	$	531,533	$	(12)

			Gross		Gross		Allowance		Estimated
	Amortized		Unrealized		Unrealized		for Credit		Fair
December 31, 2023	Cost		Gains		(Losses)		Losses		Value
	(Dollars in thousands)
Securities available-for-sale:
U.S. Treasury	$	387,990	$	—	$	(5,621)	$	—	$	382,369
Agency mortgage-backed securities		64,580		—		(4,313)		—		60,267
Total	$	452,570	$	—	$	(9,934)	$	—	$	442,636
			Gross		Gross		Estimated		Allowance
	Amortized		Unrecognized		Unrecognized		Fair		for Credit
December 31, 2023	Cost		Gains		(Losses)		Value		Losses
	(Dollars in thousands)
Securities held-to-maturity:
Agency mortgage-backed securities	$	618,374	$	282	$	(86,011)	$	532,645	$	—
Municipals - exempt from Federal tax		32,203		3		(724)		31,482		(12)
Total	$	650,577	$	285	$	(86,735)	$	564,127	$	(12)

Schedule of securities with unrealized losses

	Less Than 12 Months				12 Months or More				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
September 30, 2024	Value		(Losses)		Value		(Losses)		Value		(Losses)
	(Dollars in thousands)
Securities available-for-sale:
U.S. Treasury	$	—	$	—	$	184,162	$	(1,440)	$	184,162	$	(1,440)
Agency mortgage-backed securities		—		—		53,450		(2,923)		53,450		(2,923)
Total	$	—	$	—	$	237,612	$	(4,363)	$	237,612	$	(4,363)
Securities held-to-maturity:
Agency mortgage-backed securities	$	—	$	—	$	490,099	$	(72,377)	$	490,099	$	(72,377)
Municipals — exempt from Federal tax		4,288		(40)		20,521		(639)		24,809		(679)
Total	$	4,288	$	(40)	$	510,620	$	(73,016)	$	514,908	$	(73,056)

	Less Than 12 Months				12 Months or More				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
December 31, 2023	Value		(Losses)		Value		(Losses)		Value		(Losses)
	(Dollars in thousands)
Securities available-for-sale:
U.S. Treasury	$	4,926	$	(40)	$	377,443	$	(5,581)	$	382,369	$	(5,621)
Agency mortgage-backed securities		—		—		60,267		(4,313)		60,267		(4,313)
Total	$	4,926	$	(40)	$	437,710	$	(9,894)	$	442,636	$	(9,934)
Securities held-to-maturity:
Agency mortgage-backed securities	$	—	$	—	$	520,615	$	(86,011)	$	520,615	$	(86,011)
Municipals — exempt from Federal tax		9,790		(176)		13,151		(548)		22,941		(724)
Total	$	9,790	$	(176)	$	533,766	$	(86,559)	$	543,556	$	(86,735)

Schedule of amortized cost and estimated fair values of securities, by contractual maturity

	Available-for-sale
	Amortized		Estimated
	Cost		Fair Value
	(Dollars in thousands)
Due three months or less	$	8,981	$	8,972
Due after three months through one year		176,621		175,190
Agency mortgage-backed securities		56,373		53,450
Total	$	241,975	$	237,612
	Held-to-maturity
	Amortized		Estimated
	Cost (1)		Fair Value
	(Dollars in thousands)
Due after three months through one year	$	1,805	$	1,799
Due after one through five years		7,395		7,307
Due after five through ten years		21,384		20,802
Agency mortgage-backed securities		573,621		501,625
Total	$	604,205	$	531,533

(1) Gross of the allowance for credit losses of ($12,000) at September 30, 2024.

Schedule of roll-forward by major security type of the allowance for credit losses on debt securities held-to-maturity

		Municipals
		(Dollars in thousands)
Beginning balance January 1, 2024	$	12
Provision for credit losses		—
Ending balance September 30, 2024	$	12