Securities (Tables)

12 Months Ended

Dec. 31, 2023

Schedule Of Gain Loss On Investments Including Marketable Securities And Investments Held At Cost Income Statement Reported Amounts Summary [Line Items]

Amortized Cost and Fair Value of Debt Securities Available for Sale

Securities Available for Sale
	December 31, 2023								December 31, 2022
			Gross		Gross						Gross		Gross
	Amortized		Unrealized		Unrealized		Fair		Amortized		Unrealized		Unrealized		Fair
($ in thousands)	Cost		Gains		Losses		Value		Cost		Gains		Losses		Value
U.S. Treasury and government agency    securities	$	97,741	$	1,581	$	1,514	$	97,808	$	113,211	$	—	$	2,346	$	110,865
Municipal obligations		203,533		79		2,200		201,412		207,014		59		3,981		203,092
Residential mortgage-backed securities		2,440,411		2,734		329,279		2,113,866		2,655,381		224		398,619		2,256,986
Commercial mortgage-backed securities		2,683,872		7,176		253,576		2,437,472		3,234,278		2,032		342,880		2,893,430
Collateralized mortgage obligations		47,661		—		3,376		44,285		76,830		—		6,242		70,588
Corporate debt securities		23,500		—		3,148		20,352		23,500		—		2,420		21,080
Total	$	5,496,718	$	11,570	$	593,093	$	4,915,195	$	6,310,214	$	2,315	$	756,488	$	5,556,041

Amortized Cost and Fair Value of Debt Securities Held to Maturity

Securities Held to Maturity
	December 31, 2023								December 31, 2022
			Gross		Gross						Gross		Gross
	Amortized		Unrealized		Unrealized		Fair		Amortized		Unrealized		Unrealized		Fair
($ in thousands)	Cost		Gains		Losses		Value		Cost		Gains		Losses		Value
U.S. Treasury and government agency    securities	$	413,490	$	179	$	43,971	$	369,698	$	426,454	$	21	$	49,044	$	377,431
Municipal obligations		664,488		1,252		19,593		646,147		698,908		753		26,558		673,103
Residential mortgage-backed securities		654,262		—		59,223		595,039		734,478		—		72,532		661,946
Commercial mortgage-backed securities		920,048		—		75,803		844,245		948,691		—		87,211		861,480
Collateralized mortgage obligations		32,491		—		1,702		30,789		43,964		—		2,526		41,438
Total	$	2,684,779	$	1,431	$	200,292	$	2,485,918	$	2,852,495	$	774	$	237,871	$	2,615,398

Proceeds from Gross Gains on and Gross Losses on Sale of Securities

The following table presents the proceeds from, gross gains on, and gross losses on sales of securities during the years ended December 31, 2023, 2022 and 2021. Net gains or losses are reflected in the "Securities transactions, net" line item on the Consolidated Statements of Income.

	Years Ended December 31,
($ in thousands)	2023		2022		2021
Proceeds	$	977,114	$	73,219	$	198,681
Gross gains		—		—		1,649
Gross losses		65,380		87		1,316

Available for Sale Securities [Member]

Schedule Of Gain Loss On Investments Including Marketable Securities And Investments Held At Cost Income Statement Reported Amounts Summary [Line Items]

Amortized Cost and Fair Value of Debt Securities by Contractual Maturity

($ in thousands)	Amortized Cost		Fair Value
Debt Securities Available for Sale
Due in one year or less	$	115,178	$	113,610
Due after one year through five years		439,302		429,623
Due after five years through ten years		2,638,039		2,385,895
Due after ten years		2,304,199		1,986,067
Total available for sale debt securities	$	5,496,718	$	4,915,195

Securities with Unrealized Losses

Available for sale
	December 31, 2023
	Losses < 12 Months				Losses 12 Months or >				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
($ in thousands)	Value		Losses		Value		Losses		Value		Losses
U.S. Treasury and government agency securities	$	—	$	—	$	7,790	$	1,514	$	7,790	$	1,514
Municipal obligations		49,832		374		128,965		1,826		178,797		2,200
Residential mortgage-backed securities		3,062		25		1,795,154		329,254		1,798,216		329,279
Commercial mortgage-backed securities		—		—		2,227,703		253,576		2,227,703		253,576
Collateralized mortgage obligations		—		—		44,285		3,376		44,285		3,376
Corporate debt securities		—		—		19,852		3,148		19,852		3,148
Total	$	52,894	$	399	$	4,223,749	$	592,694	$	4,276,643	$	593,093

Available for sale
	December 31, 2022
	Losses < 12 Months				Losses 12 Months or >				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
($ in thousands)	Value		Losses		Value		Losses		Value		Losses
U.S. Treasury and government agency securities	$	102,607	$	754	$	8,258	$	1,592	$	110,865	$	2,346
Municipal obligations		192,334		3,981		—		—		192,334		3,981
Residential mortgage-backed securities		636,060		49,790		1,611,832		348,829		2,247,892		398,619
Commercial mortgage-backed securities		1,489,974		114,195		1,351,530		228,685		2,841,504		342,880
Collateralized mortgage obligations		41,703		3,275		28,884		2,967		70,587		6,242
Corporate debt securities		13,194		1,306		7,386		1,114		20,580		2,420
Total	$	2,475,872	$	173,301	$	3,007,890	$	583,187	$	5,483,762	$	756,488

Held-to-maturity Securities [Member]

Schedule Of Gain Loss On Investments Including Marketable Securities And Investments Held At Cost Income Statement Reported Amounts Summary [Line Items]

Amortized Cost and Fair Value of Debt Securities by Contractual Maturity

($ in thousands)	Amortized Cost		Fair Value
Debt Securities Held to Maturity
Due in one year or less	$	91,699	$	90,110
Due after one year through five years		664,913		634,463
Due after five years through ten years		791,158		742,927
Due after ten years		1,137,009		1,018,418
Total held to maturity debt securities	$	2,684,779	$	2,485,918

Securities with Unrealized Losses

Held to maturity
	December 31, 2023
	Losses < 12 Months				Losses 12 Months or >				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
($ in thousands)	Value		Losses		Value		Losses		Value		Losses
U.S. Treasury and government agency securities	$	9,530	$	63	$	339,533	$	43,908	$	349,063	$	43,971
Municipal obligations		343,401		1,801		226,165		17,792		569,566		19,593
Residential mortgage-backed securities		—		—		595,039		59,223		595,039		59,223
Commercial mortgage-backed securities		—		—		844,245		75,803		844,245		75,803
Collateralized mortgage obligations		—		—		30,789		1,702		30,789		1,702
Total	$	352,931	$	1,864	$	2,035,771	$	198,428	$	2,388,702	$	200,292

Held to maturity	December 31, 2022
	Losses < 12 Months				Losses 12 Months or >				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
($ in thousands)	Value		Losses		Value		Losses		Value		Losses
U.S. Treasury and government agency securities	$	145,893	$	13,245	$	226,499	$	35,799	$	372,392	$	49,044
Municipal obligations		560,288		8,878		64,346		17,680		624,634		26,558
Residential mortgage-backed securities		391,146		30,515		270,800		42,017		661,946		72,532
Commercial mortgage-backed securities		697,827		56,899		163,653		30,312		861,480		87,211
Collateralized mortgage obligations		41,438		2,526		—		—		41,438		2,526
Total	$	1,836,592	$	112,063	$	725,298	$	125,808	$	2,561,890	$	237,871