Investment Securities (Tables)

3 Months Ended

Mar. 31, 2024

Investment Securities

Schedule of amortized cost and fair values of investment securities

	Amortized		Gross Unrealized				Estimated
(Dollars in thousands)	Cost		Gains		Losses		Fair Value			ACL
March 31, 2024:
Available-for-sale:
Mortgage-backed securities issued by U.S. government-sponsored enterprises	$	22,415	$	—	$	(2,932)	$	19,483	$	—
Held-to-maturity:
Mortgage-backed securities issued by U.S. government agencies or U.S. government-sponsored enterprises		677,578		36		(130,324)		547,290		—
Total	$	699,993	$	36	$	(133,256)	$	566,773	$	—
December 31, 2023:
Available-for-sale:
Mortgage-backed securities issued by U.S. government-sponsored enterprises	$	22,563	$	—	$	(2,392)	$	20,171	$	—
Held-to-maturity:
Mortgage-backed securities issued by U.S. government agencies or U.S. government-sponsored enterprises		685,728		68		(117,668)		568,128		—
Total	$	708,291	$	68	$	(120,060)	$	588,299	$	—

Schedule of amortized cost and estimated fair value of investment securities by maturity

	Amortized		Estimated
(Dollars in thousands)	Cost		Fair Value
Available-for-sale:
Due after 10 years	$	22,415	$	19,483
Total	$	22,415	$	19,483
Held-to-maturity:
Due within 5 years	$	12	$	12
Due after 5 years through 10 years		6		6
Due after 10 years		677,560		547,272
Total	$	677,578	$	547,290

Summary of investment securities in an unrealized loss position

	Less Than 12 Months				12 Months or Longer				Total
			Unrealized				Unrealized		Number of			Unrealized
Description of securities	Fair Value		Losses		Fair Value		Losses		Securities	Fair Value		Losses
(Dollars in thousands)
March 31, 2024:
Available-for-sale:
Mortgage-backed securities issued by U.S. government-sponsored enterprises	$	—	$	—	$	19,483	$	(2,932)	4	$	19,483	$	(2,932)
Held-to-maturity:
Mortgage-backed securities issued by U.S. government agencies or U.S. government-sponsored enterprises		—		—		544,088		(130,324)	152		544,088		(130,324)
Total	$	—	$	—	$	563,571	$	(133,256)	156	$	563,571	$	(133,256)
December 31, 2023:
Available-for-sale:
Mortgage-backed securities issued by U.S. government sponsored enterprises	$	—	$	—	$	20,171	$	(2,392)	4	$	20,171	$	(2,392)
Held-to-maturity:
Mortgage-backed securities issued by U.S. government agencies or U.S. government-sponsored enterprises		10,326		(107)		554,514		(117,561)	152		564,840		(117,668)
Total	$	10,326	$	(107)	$	574,685	$	(119,953)	156	$	585,011	$	(120,060)