Investment Securities (Tables)

6 Months Ended

Jun. 30, 2021

Investments, Debt and Equity Securities [Abstract]

Schedule of investment securities available-for-sale

The following table shows investment securities available-for-sale.

(Dollars in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
June 30, 2021
U.S. Treasury and Federal agencies securities	$	767,147	$	6,325	$	(3,594)	$	769,878
U.S. States and political subdivisions securities	89,938		1,761		(564)		91,135
Mortgage-backed securities — Federal agencies	517,713		8,093		(2,911)		522,895
Corporate debt securities	27,508		906		—		28,414
Foreign government and other securities	700		—		—		700
Total debt securities available-for-sale	$	1,403,006	$	17,085	$	(7,069)	$	1,413,022
December 31, 2020
U.S. Treasury and Federal agencies securities	$	610,195	$	9,521	$	(234)	$	619,482
U.S. States and political subdivisions securities	78,812		2,346		(31)		81,127
Mortgage-backed securities — Federal agencies	442,748		11,237		(196)		453,789
Corporate debt securities	40,813		1,556		—		42,369
Foreign government and other securities	700		—		—		700
Total debt securities available-for-sale	$	1,173,268	$	24,660	$	(461)	$	1,197,467

Schedule of contractual maturities of investments in debt securities available-for-sale

The following table shows the contractual maturities of investments in debt securities available-for-sale at June 30, 2021. Expected maturities will differ from contractual maturities, because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.

(Dollars in thousands)	Amortized Cost		Fair Value
Due in one year or less	$	104,525	$	105,576
Due after one year through five years	633,313		638,184
Due after five years through ten years	146,985		145,918
Due after ten years	470		449
Mortgage-backed securities	517,713		522,895
Total debt securities available-for-sale	$	1,403,006	$	1,413,022

Schedule of gross unrealized losses and fair value by investment category and age

The following table summarizes gross unrealized losses and fair value by investment category and age. At June 30, 2021, the Company’s available-for-sale securities portfolio consisted of 657 securities, 169 of which were in an unrealized loss position.

	Less than 12 Months				12 months or Longer				Total
(Dollars in thousands)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
June 30, 2021
U.S. Treasury and Federal agencies securities	$	405,494	$	(3,594)	$	—	$	—	$	405,494	$	(3,594)
U.S. States and political subdivisions securities	31,702		(545)		421		(19)		32,123		(564)
Mortgage-backed securities - Federal agencies	232,737		(2,904)		550		(7)		233,287		(2,911)
Corporate debt securities	—		—		—		—		—		—
Foreign government and other securities	200		—		—		—		200		—
Total debt securities available-for-sale	$	670,133	$	(7,043)	$	971	$	(26)	$	671,104	$	(7,069)
December 31, 2020
U.S. Treasury and Federal agencies securities	$	136,534	$	(234)	$	—	$	—	$	136,534	$	(234)
U.S. States and political subdivisions securities	6,391		(30)		199		(1)		6,590		(31)
Mortgage-backed securities - Federal agencies	67,736		(187)		3,274		(9)		71,010		(196)
Corporate debt securities	—		—		—		—		—		—
Foreign government and other securities	200		—		—		—		200		—
Total debt securities available-for-sale	$	210,861	$	(451)	$	3,473	$	(10)	$	214,334	$	(461)

Schedule of gross realized gains and losses from securities available-for-sale portfolio

The following table shows the gross realized gains and losses from the available-for-sale debt securities portfolio. Realized gains and losses of all securities are computed using the specific identification cost basis.

	Three Months Ended June 30,				Six Months Ended June 30,
(Dollars in thousands)	2021		2020		2021		2020
Gross realized gains	$	221	$	5	$	221	$	285
Gross realized losses	(901)		(6)		(901)		(6)
Net realized gains (losses)	$	(680)	$	(1)	$	(680)	$	279