Securities (Tables)

12 Months Ended

Dec. 31, 2020

Investments, Debt and Equity Securities [Abstract]

Book Values and Approximate Fair Values of Investment Securities

The book values and approximate fair values of investment securities at December 31, 2020 and 2019 are summarized as follows:

	2020					2019
	Amortized Cost		Fair Value	Unrealized		Amortized Cost	Fair Value	Unrealized
($ in thousands)				Gains	(Losses)			Gains	(Losses)
Securities available for sale:
Government-sponsored enterprise securities	$	70,016	70,206	371	(181)	20,000	20,009	17	(8)
Mortgage-backed securities	1,318,998		1,337,706	20,832	(2,124)	758,491	767,285	9,463	(669)
Corporate bonds	43,670		45,220	1,760	(210)	33,711	34,651	1,025	(85)
Total available for sale	1,432,684		1,453,132	22,963	(2,515)	812,202	821,945	10,505	(762)
Securities held to maturity:
Mortgage-backed securities	29,959		30,900	941	—	41,423	41,542	125	(6)
State and local governments	137,592		139,834	2,407	(165)	26,509	26,791	285	(3)
Total held to maturity	$	167,551	170,734	3,348	(165)	67,932	68,333	410	(9)

Schedule of Information Regarding Securities with Unrealized Losses

The following table presents information regarding securities with unrealized losses at December 31, 2020:

($ in thousands)	Securities in an Unrealized Loss Position for Less than 12 Months			Securities in an Unrealized Loss Position for More than 12 Months		Total
	Fair Value		Unrealized Losses	Fair Value	Unrealized Losses	Fair Value	Unrealized Losses
Government-sponsored enterprise securities	$	29,812	181	—	—	29,812	181
Mortgage-backed securities	497,992		1,957	6,168	167	504,160	2,124
Corporate bonds	3,956		45	835	165	4,791	210
State and local governments	23,310		165	—	—	23,310	165
Total temporarily impaired securities	$	555,070	2,348	7,003	332	562,073	2,680

The following table presents information regarding securities with unrealized losses at December 31, 2019:

($ in thousands)	Securities in an Unrealized Loss Position for Less than 12 Months			Securities in an Unrealized Loss Position for More than 12 Months		Total
	Fair Value		Unrealized Losses	Fair Value	Unrealized Losses	Fair Value	Unrealized Losses
Government-sponsored enterprise securities	$	4,992	8	—	—	4,992	8
Mortgage-backed securities	77,274		293	50,851	382	128,125	675
Corporate bonds	—		—	915	85	915	85
State and local governments	—		—	934	3	934	3
Total temporarily impaired securities	$	82,266	301	52,700	470	134,966	771

Schedule of Book Values and Approximate Fair Values of Investment Securities by Contractual Maturity

The book values and approximate fair values of investment securities at December 31, 2020, by contractual maturity, are summarized in the table below. Expected maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties.

	Securities Available for Sale			Securities Held to Maturity
($ in thousands)	Amortized Cost		Fair Value	Amortized Cost		Fair Value
Debt securities
Due within one year	$	—	—	$	2,087	2,101
Due after one year but within five years	28,670		30,265	2,915		3,008
Due after five years but within ten years	74,016		74,400	3,418		3,536
Due after ten years	11,000		10,761	129,172		131,189
Mortgage-backed securities	1,318,998		1,337,706	29,959		30,900
Total securities	$	1,432,684	1,453,132	$	167,551	170,734