Investment Securities (Tables)

12 Months Ended

Dec. 31, 2019

Investment Securities.

Schedule of amortized cost and fair values of investment securities

	Amortized		Gross Unrealized				Estimated
(Dollars in thousands)	Cost		Gains		Losses		Fair Value
December 31, 2019:
Available-for-sale:
U.S. government-sponsored mortgage-backed securities	$	7,905	$	723	$	—	$	8,628
Total	$	7,905	$	723	$	—	$	8,628
Held-to-maturity:
U.S. government-sponsored mortgage-backed securities	$	363,883	$	8,436	$	(1,014)	$	371,305
Total	$	363,883	$	8,436	$	(1,014)	$	371,305
December 31, 2018:
Available-for-sale:
U.S. government-sponsored mortgage-backed securities	$	2,644	$	—	$	(84)	$	2,560
Total	$	2,644	$	—	$	(84)	$	2,560
Held-to-maturity:
U.S. government-sponsored mortgage-backed securities	$	371,442	$	2,056	$	(9,279)	$	364,219
Trust preferred securities		75		628		—		703
Total	$	371,517	$	2,684	$	(9,279)	$	364,922

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 within 5 years	$	—	$	—
Due after 5 years through 10 years		—		—
Due after 10 years		7,905		8,628
Total	$	7,905	$	8,628
Held-to-maturity:
Due within 5 years	$	—	$	—
Due after 5 years through 10 years		60		61
Due after 10 years		363,823		371,244
Total	$	363,883	$	371,305

Schedule of realized gains and losses and proceeds from sales of securities held to maturity

(Dollars in thousands)	2019		2018
Proceeds from sales	$	8,644	$	4,462
Gross gains		2,910		45
Gross losses		—		—

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)
December 31, 2019:
Held-to-maturity:
U.S. government-sponsored mortgage-backed securities	$	55,882	$	(302)	$	34,492	$	(712)	30	$	90,374	$	(1,014)
December 31, 2018:
Available-for-sale:
U.S. government-sponsored mortgage-backed securities	$	—	$	—	$	2,560	$	(84)	1	$	2,560	$	(84)
Held-to-maturity:
U.S. government-sponsored mortgage-backed securities	$	57,154	$	(254)	$	220,338	$	(9,025)	81	$	277,492	$	(9,279)