Loans and Allowances for Credit Losses (Tables)

6 Months Ended

Jun. 30, 2024

Loans and Leases Receivable, Net Amount [Abstract]

Schedule of Loans by Portfolio Segment [Table Text Block]

Portfolio segments of the loan portfolio are as follows (in thousands):

	June 30, 2024								December 31, 2023
	Fixed Rate		Variable Rate		Non-accrual		Total		Fixed Rate		Variable Rate		Non-accrual		Total
Commercial	$	3,604,024	$	11,960,951	$	58,434	$	15,623,409	$	3,558,563	$	11,135,075	$	110,131	$	14,803,769
Commercial real estate	756,055		4,314,637		12,883		5,083,575		791,757		4,538,570		7,320		5,337,647
Loans to individuals	2,428,707		1,398,524		19,366		3,846,597		2,282,914		1,452,620		28,018		3,763,552
Total	$	6,788,786	$	17,674,112	$	90,683	$	24,553,581	$	6,633,234	$	17,126,265	$	145,469	$	23,904,968

Rollforward of Allowance For Loan Losses And Accrual for Off-Balance Sheet Credit Losses [Table Text Block]

The activity in the allowance for loan losses and the allowance for off-balance sheet credit losses related to loan commitments and standby letters of credit is summarized as follows (in thousands):

	Three Months Ended
	June 30, 2024
	Commercial		Commercial Real Estate		Loans to Individuals		Total
Allowance for loan losses:
Beginning balance	$	146,267	$	97,479	$	37,877	$	281,623
Provision for loan losses	10,441		(1,042)		3,749		13,148
Loans charged off	(6,391)		(205)		(1,344)		(7,940)
Recoveries of loans previously charged off	420		24		551		995
Ending balance	$	150,737	$	96,256	$	40,833	$	287,826
Allowance for off-balance sheet credit risk from unfunded loan commitments:
Beginning balance	$	17,790	$	27,865	$	1,664	$	47,319
Provision for off-balance sheet credit risk	(474)		(4,551)		42		(4,983)
Ending balance	$	17,316	$	23,314	$	1,706	$	42,336

	Six Months Ended
	June 30, 2024
	Commercial		Commercial Real Estate		Loans to Individuals		Total
Allowance for loan losses:
Beginning balance	$	141,232	$	94,718	$	41,173	$	277,123
Provision for loan losses	18,752		2,953		1,403		23,108
Loans charged off	(10,631)		(1,455)		(2,914)		(15,000)
Recoveries of loans previously charged off	1,384		40		1,171		2,595
Ending balance	$	150,737	$	96,256	$	40,833	$	287,826
Allowance for off-balance sheet credit risk from unfunded loan commitments:
Beginning balance	$	19,762	$	27,439	$	1,776	$	48,977
Provision for off-balance sheet credit risk	(2,446)		(4,125)		(70)		(6,641)
Ending balance	$	17,316	$	23,314	$	1,706	$	42,336

	Three Months Ended
	June 30, 2023
	Commercial		Commercial Real Estate		Loans to Individuals		Total
Allowance for loan losses:
Beginning balance	$	139,898	$	66,003	$	43,559	$	249,460
Provision for loan losses	5,420		14,300		237		19,957
Loans charged off	(2,797)		(4,000)		(1,252)		(8,049)
Recoveries of loans previously charged off	748		44		554		1,346
Ending balance	$	143,269	$	76,347	$	43,098	$	262,714
Allowance for off-balance sheet credit risk from unfunded loan commitments:
Beginning balance	$	20,608	$	40,211	$	2,124	$	62,943
Provision for off-balance sheet credit risk	(314)		(2,530)		(159)		(3,003)
Ending balance	$	20,294	$	37,681	$	1,965	$	59,940

	Six Months Ended
	June 30, 2023
	Commercial		Commercial Real Estate		Loans to Individuals		Total
Allowance for loan losses:
Beginning balance	$	131,586	$	57,648	$	46,470	$	235,704
Provision for loan losses	11,750		24,726		(1,994)		34,482
Loans charged off	(2,809)		(6,208)		(2,699)		(11,716)
Recoveries of loans previously charged off	2,742		181		1,321		4,244
Ending balance	$	143,269	$	76,347	$	43,098	$	262,714
Allowance for off-balance sheet credit risk from unfunded loan commitments:
Beginning balance	$	18,246	$	40,490	$	2,183	$	60,919
Provision for off-balance sheet credit risk	2,048		(2,809)		(218)		(979)
Ending balance	$	20,294	$	37,681	$	1,965	$	59,940

An $8.0 million provision for credit losses was necessary for the second quarter of 2024, reflecting continued loan growth and a stable economic outlook.

The allowance for loan losses and recorded investment of the related loans by portfolio segment for each measurement method at June 30, 2024 is as follows (in thousands):

	Collectively Measured for General Allowances				Individually Measured for Specific Allowances				Total
	Recorded Investment		Related Allowance		Recorded Investment		Related Allowance		Recorded Investment		Related Allowance
Commercial	$	15,564,975	$	148,523	$	58,434	$	2,214	$	15,623,409	$	150,737
Commercial real estate	5,070,692		96,256		12,883		—		5,083,575		96,256
Loans to individuals	3,827,231		40,833		19,366		—		3,846,597		40,833
Total	$	24,462,898	$	285,612	$	90,683	$	2,214	$	24,553,581	$	287,826

The allowance for loan losses and recorded investment of the related loans by portfolio segment for each measurement method at December 31, 2023 is as follows (in thousands):

	Collectively Measured for General Allowances				Individually Measured for Specific Allowances				Total
	Recorded Investment		Related Allowance		Recorded Investment		Related Allowance		Recorded Investment		Related Allowance
Commercial	$	14,693,638	$	138,540	$	110,131	$	2,692	$	14,803,769	$	141,232
Commercial real estate	5,330,327		94,718		7,320		—		5,337,647		94,718
Loans to individuals	3,735,534		41,173		28,018		—		3,763,552		41,173
Total	$	23,759,499	$	274,431	$	145,469	$	2,692	$	23,904,968	$	277,123

Schedule of Credit Quality Indicators [Table Text Block]

The following table summarizes the Company’s loan portfolio at June 30, 2024 by the risk grade categories and vintage (in thousands): 

	Origination Year
	2024		2023		2022		2021		2020		Prior		Revolving Loans		Revolving Loans Converted to Term Loans		Total
Commercial:
Healthcare
Pass	$	275,268	$	625,281	$	921,843	$	565,653	$	379,669	$	992,889	$	262,814	$	12	$	4,023,429
Special Mention	—		15,000		31,907		1,178		—		49,823		505		—		98,413
Accruing Substandard	—		—		110		18,287		58,103		10,896		975		—		88,371
Nonaccrual	—		1,375		237		—		—		19,233		—		—		20,845
Total healthcare	275,268		641,656		954,097		585,118		437,772		1,072,841		264,294		12		4,231,058
Loans charged off, year-to-date	—		—		—		—		—		6,840		—		—		6,840
Services
Pass	330,400		735,946		506,992		350,009		211,087		691,191		704,785		459		3,530,869
Special Mention	—		1,814		1,035		898		—		8,330		1,758		—		13,835
Accruing Substandard	—		—		17,437		147		1,607		8,929		436		719		29,275
Nonaccrual	—		—		—		1,361		363		—		1,441		—		3,165
Total services	330,400		737,760		525,464		352,415		213,057		708,450		708,420		1,178		3,577,144
Loans charged off, year-to-date	—		—		—		—		10		—		9		—		19
Energy
Pass	55,874		103,305		78,634		2,707		7,288		20,140		3,123,257		—		3,391,205
Special Mention	—		—		—		—		—		—		17,662		—		17,662
Accruing Substandard	—		—		—		—		—		—		13,950		—		13,950
Nonaccrual	—		—		—		—		—		80		28,588		—		28,668
Total energy	55,874		103,305		78,634		2,707		7,288		20,220		3,183,457		—		3,451,485
Loans charged off, year-to-date	—		—		—		—		—		—		—		—		—
General business
Pass	543,566		741,365		376,769		191,698		128,816		346,596		1,918,875		1,733		4,249,418
Special Mention	2,488		15,760		5,201		11,765		535		1,764		9,307		—		46,820
Accruing Substandard	—		4,090		38,900		1,542		1,193		6,539		9,301		163		61,728
Nonaccrual	—		994		66		—		—		35		4,658		3		5,756
Total general business	546,054		762,209		420,936		205,005		130,544		354,934		1,942,141		1,899		4,363,722
Loans charged off, year-to-date	—		27		1,399		—		—		158		2,182		6		3,772
Total commercial	1,207,596		2,244,930		1,979,131		1,145,245		788,661		2,156,445		6,098,312		3,089		15,623,409
Commercial real estate:
Pass	39,377		449,401		2,084,982		919,126		343,462		1,025,082		136,787		—		4,998,217
Special Mention	—		403		14,907		32,131		—		16,949		—		—		64,390
Accruing Substandard	—		—		—		—		—		8,085		—		—		8,085
Nonaccrual	—		2,885		—		—		—		9,998		—		—		12,883
Total commercial real estate	39,377		452,689		2,099,889		951,257		343,462		1,060,114		136,787		—		5,083,575
Loans charged off, year-to-date	—		—		—		—		—		1,455		—		—		1,455

	Origination Year
	2024		2023		2022		2021		2020		Prior		Revolving Loans		Revolving Loans Converted to Term Loans		Total
Loans to individuals:
Residential mortgage
Pass	249,631		377,061		308,510		330,796		332,439		267,548		378,185		21,123		2,265,293
Special Mention	—		42		193		176		—		155		1,575		—		2,141
Accruing Substandard	—		49		—		3		—		—		1,113		—		1,165
Nonaccrual	—		107		433		434		510		8,218		2,377		548		12,627
Total residential mortgage	249,631		377,259		309,136		331,409		332,949		275,921		383,250		21,671		2,281,226
Loans charged off, year-to-date	—		—		—		—		—		5		9		—		14
Residential mortgage guaranteed by U.S. government agencies
Pass	—		893		3,466		2,727		3,982		114,140		—		—		125,208
Nonaccrual	—		—		—		—		280		6,337		—		—		6,617
Total residential mortgage guaranteed by U.S. government agencies	—		893		3,466		2,727		4,262		120,477		—		—		131,825
Personal
Pass	148,880		180,029		187,435		133,383		110,809		171,280		499,184		92		1,431,092
Special Mention	—		28		35		65		15		2		1		—		146
Accruing Substandard	—		30		12		3		7		144		1,990		—		2,186
Nonaccrual	—		26		44		11		9		8		24		—		122
Total personal	148,880		180,113		187,526		133,462		110,840		171,434		501,199		92		1,433,546
Loans charged off, year-to-date1	2,732		51		45		26		—		—		26		20		2,900
Total loans to individuals	398,511		558,265		500,128		467,598		448,051		567,832		884,449		21,763		3,846,597
Total loans	$	1,645,484	$	3,255,884	$	4,579,148	$	2,564,100	$	1,580,174	$	3,784,391	$	7,119,548	$	24,852	$	24,553,581

1    Includes charge-offs on deposit overdrafts, which are generally charged off at 60 days past due.

The following table summarizes the Company's loan portfolio at December 31, 2023 by the risk grade categories and vintage (in thousands): 

	Origination Year
	2023		2022		2021		2020		2019		Prior		Revolving Loans		Revolving Loans Converted to Term Loans		Total
Commercial:
Healthcare
Pass	650,768		895,602		590,736		409,001		331,897		809,858		281,378		15		3,969,255
Special Mention	—		—		—		21,791		—		31,235		5		—		53,031
Accruing Substandard	—		2,128		18,508		6,911		—		10,896		975		—		39,418
Nonaccrual	—		—		—		30,290		23,129		28,110		—		—		81,529
Total healthcare	650,768		897,730		609,244		467,993		355,026		880,099		282,358		15		4,143,233
Loans charged off, year-to-date	—		—		—		—		2,500		—		—		—		2,500
Services
Pass	900,090		526,776		401,872		228,818		106,112		643,477		730,729		595		3,538,469
Special Mention	—		1,085		1,520		1,341		534		4,522		81		—		9,083
Accruing Substandard	—		13,712		178		326		3,972		3,746		3,108		13		25,055
Nonaccrual	—		—		1,635		338		—		—		1,643		—		3,616
Total services	900,090		541,573		405,205		230,823		110,618		651,745		735,561		608		3,576,223
Loans charged off, year-to-date	—		—		3,060		—		—		—		2,642		—		5,702
Energy
Pass	$	190,122	$	100,006	$	43,769	$	7,876	$	9,562	$	11,583	$	3,025,590	$	—	$	3,388,508
Special Mention	—		—		—		—		—		—		13,950		—		13,950
Accruing Substandard	—		—		—		—		—		—		16,800		—		16,800
Nonaccrual	—		—		—		—		—		99		17,744		—		17,843
Total energy	190,122		100,006		43,769		7,876		9,562		11,682		3,074,084		—		3,437,101
General business
Pass	942,468		436,832		224,735		138,951		101,100		287,744		1,389,128		2,164		3,523,122
Special Mention	10,264		16,167		8,420		1,253		321		8,295		897		—		45,617
Accruing Substandard	4,401		33,194		1,716		27		—		—		31,992		—		71,330
Nonaccrual	—		1,134		—		—		—		48		5,956		5		7,143
Total general business	957,133		487,327		234,871		140,231		101,421		296,087		1,427,973		2,169		3,647,212
Loans charged off, year-to-date	—		—		4,598		2		—		48		10		38		4,696
Total commercial	2,698,113		2,026,636		1,293,089		846,923		576,627		1,839,613		5,519,976		2,792		14,803,769
Commercial real estate:
Pass	396,891		1,941,913		1,194,759		416,647		513,555		705,092		136,095		—		5,304,952
Special Mention	—		476		—		—		—		19,171		—		—		19,647
Accruing Substandard	2,992		—		3		—		—		2,733		—		—		5,728
Nonaccrual	—		—		—		—		7,170		150		—		—		7,320
Total commercial real estate	399,883		1,942,389		1,194,762		416,647		520,725		727,146		136,095		—		5,337,647
Loans charged off, year-to-date	—		—		—		—		—		8,446		—		—		8,446

	Origination Year
	2023		2022		2021		2020		2019		Prior		Revolving Loans		Revolving Loans Converted to Term Loans		Total
Loans to individuals:
Residential mortgage
Pass	426,089		320,733		342,927		349,742		54,801		243,356		375,739		23,895		2,137,282
Special Mention	157		140		131		1,361		18		134		2,982		93		5,016
Accruing Substandard	—		150		—		—		37		49		50		—		286
Nonaccrual	79		1,419		237		544		344		12,381		2,387		665		18,056
Total residential mortgage	426,325		322,442		343,295		351,647		55,200		255,920		381,158		24,653		2,160,640
Loans charged off, year-to-date	—		—		51		4		—		17		—		1		73
Residential mortgage guaranteed by U.S. government agencies
Pass	633		1,788		2,220		4,297		6,441		124,719		—		—		140,098
Nonaccrual	—		—		—		280		375		9,054		—		—		9,709
Total residential mortgage guaranteed by U.S. government agencies	633		1,788		2,220		4,577		6,816		133,773		—		—		149,807
Personal
Pass	218,401		229,580		149,291		136,215		75,348		137,629		503,841		145		1,450,450
Special Mention	66		39		106		30		8		—		1,918		3		2,170
Accruing Substandard	—		64		12		9		144		—		3		—		232
Nonaccrual	4		51		9		16		3		12		158		—		253
Total personal	218,471		229,734		149,418		136,270		75,503		137,641		505,920		148		1,453,105
Loans charged off, year-to-date1	5,636		82		96		43		—		10		6		26		5,899
Total loans to individuals	645,429		553,964		494,933		492,494		137,519		527,334		887,078		24,801		3,763,552
Total loans	$	3,743,425	$	4,522,989	$	2,982,784	$	1,756,064	$	1,234,871	$	3,094,093	$	6,543,149	$	27,593	$	23,904,968

1    Includes charge-offs on deposit overdrafts, which are generally charged off at 60 days past due.

Financing Receivable, Nonaccrual [Table Text Block]

A summary of nonaccruing loans at June 30, 2024 follows (in thousands): 

	As of June 30, 2024
	Total		With No Allowance		With Allowance		Related Allowance
Commercial:
Healthcare	$	20,845	$	10,930	$	9,915	$	1,700
Services	3,165		1,521		1,644		441
Energy	28,668		28,668		—		—
General business	5,756		5,618		138		73
Total commercial	58,434		46,737		11,697		2,214
Commercial real estate	12,883		12,883		—		—
Loans to individuals:
Residential mortgage	12,627		12,627		—		—
Residential mortgage guaranteed by U.S. government agencies	6,617		6,617		—		—
Personal	122		122		—		—
Total loans to individuals	19,366		19,366		—		—
Total	$	90,683	$	78,986	$	11,697	$	2,214

A summary of nonaccruing loans at December 31, 2023 follows (in thousands): 

	As of December 31, 2023
	Total		With No Allowance		With Allowance		Related Allowance
Commercial:
Healthcare	$	81,529	$	40,372	$	41,157	$	1,478
Services	3,616		1,684		1,932		1,214
Energy	17,843		17,843		—		—
General business	7,143		7,143		—		—
Total commercial	110,131		67,042		43,089		2,692
Commercial real estate	7,320		7,320		—		—
Loans to individuals:
Residential mortgage	18,056		18,056		—		—
Residential mortgage guaranteed by U.S. government agencies	9,709		9,709		—		—
Personal	253		253		—		—
Total loans to individuals	28,018		28,018		—		—
Total	$	145,469	$	102,380	$	43,089	$	2,692

Summary of Loans by Aging Status [Table Text Block]

A summary of loans currently performing and past due as of June 30, 2024 is as follows (in thousands):

			Past Due								Past Due 90 Days or More and Accruing
	Current		30 to 59 Days		60 to 89 Days		90 Days or More		Total
Commercial:
Healthcare	$	4,214,505	$	1,375	$	4,415	$	10,763	$	4,231,058	$	—
Services	3,575,551		—		1,158		435		3,577,144		72
Energy	3,451,485		—		—		—		3,451,485		—
General business	4,354,147		1,044		163		8,368		4,363,722		2,794
Total commercial	15,595,688		2,419		5,736		19,566		15,623,409		2,866
Commercial real estate	5,073,416		—		3,021		7,138		5,083,575		—
Loans to individuals:
Residential mortgage	2,267,945		9,907		1,615		1,759		2,281,226		97
Residential mortgage guaranteed by U.S. government agencies	40,693		23,918		15,796		51,418		131,825		46,579
Personal	1,432,561		933		52		—		1,433,546		—
Total loans to individuals	3,741,199		34,758		17,463		53,177		3,846,597		46,676
Total	$	24,410,303	$	37,177	$	26,220	$	79,881	$	24,553,581	$	49,542

A summary of loans currently performing and past due as of December 31, 2023 is as follows (in thousands):

			Past Due								Past Due 90 Days or More and Accruing
	Current		30 to 59 Days		60 to 89 Days		90 Days or More		Total
Commercial:
Healthcare	$	4,071,336	$	18,019	$	30,290	$	23,588	$	4,143,233	$	—
Services	3,575,787		2		—		434		3,576,223		—
Energy	3,437,101		—		—		—		3,437,101		—
General business	3,639,775		412		1,157		5,868		3,647,212		—
Total commercial	14,723,999		18,433		31,447		29,890		14,803,769		—
Commercial real estate	5,327,481		2,992		—		7,174		5,337,647		3
Loans to individuals:
Residential mortgage	2,149,927		6,340		1,494		2,879		2,160,640		36
Residential mortgage guaranteed by U.S. government agencies	54,122		25,085		17,053		53,547		149,807		48,201
Personal	1,450,302		2,561		88		154		1,453,105		131
Total loans to individuals	3,654,351		33,986		18,635		56,580		3,763,552		48,368
Total	$	23,705,831	$	55,411	$	50,082	$	93,644	$	23,904,968	$	48,371