Loans and Allowances for Credit Losses (Tables)

6 Months Ended

Jun. 30, 2023

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, 2023								December 31, 2022
	Fixed Rate		Variable Rate		Non-accrual		Total		Fixed Rate		Variable Rate		Non-accrual		Total
Commercial	$	3,492,786	$	10,968,453	$	73,277	$	14,534,516	$	3,392,422	$	10,759,780	$	60,297	$	14,212,499
Commercial real estate	878,947		4,074,459		17,395		4,970,801		874,716		3,715,491		16,570		4,606,777
Loans to individuals	2,133,208		1,557,555		41,579		3,732,342		2,099,165		1,593,779		44,930		3,737,874
Total	$	6,504,941	$	16,600,467	$	132,251	$	23,237,659	$	6,366,303	$	16,069,050	$	121,797	$	22,557,150

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, 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	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 losses	2,048		(2,809)		(218)		(979)
Ending balance	$	20,294	$	37,681	$	1,965	$	59,940

	Three Months Ended
	June 30, 2022
	Commercial		Commercial Real Estate		Loans to Individuals		Total
Allowance for loan losses:
Beginning balance	$	151,448	$	58,974	$	36,051	$	246,473
Provision for loan losses	(15,468)		4,085		5,225		(6,158)
Loans charged off	(6)		(78)		(1,284)		(1,368)
Recoveries of loans previously charged off	1,588		16		563		2,167
Ending balance	$	137,562	$	62,997	$	40,555	$	241,114
Allowance for off-balance sheet credit risk from unfunded loan commitments:
Beginning balance	$	13,966	$	20,465	$	1,814	$	36,245
Provision for off-balance sheet credit risk	1,873		4,205		(73)		6,005
Ending balance	$	15,839	$	24,670	$	1,741	$	42,250

	Six Months Ended
	June 30, 2022
	Commercial		Commercial Real Estate		Loans to Individuals		Total
Allowance for loan losses:
Beginning balance	$	162,056	$	58,553	$	35,812	$	256,421
Provision for loan losses	(20,586)		4,553		5,908		(10,125)
Loans charged off	(6,087)		(269)		(2,817)		(9,173)
Recoveries of loans previously charged off	2,179		160		1,652		3,991
Ending balance	$	137,562	$	62,997	$	40,555	$	241,114
Allowance for off-balance sheet credit risk from unfunded loan commitments:
Beginning balance	$	13,812	$	17,442	$	1,723	$	32,977
Provision for off-balance sheet credit risk	2,027		7,228		18		9,273
Ending balance	$	15,839	$	24,670	$	1,741	$	42,250

A $17.0 million provision for credit losses was necessary for the second quarter of 2023, primarily related to higher assumed commercial real estate vacancy rates during the forecast period and overall loan portfolio growth during the quarter.

The allowance for loan losses and recorded investment of the related loans by portfolio segment for each measurement method at June 30, 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	$	14,461,239	$	135,453	$	73,277	$	7,816	$	14,534,516	$	143,269
Commercial real estate	4,953,406		74,797		17,395		1,550		4,970,801		76,347
Loans to individuals	3,690,763		43,098		41,579		—		3,732,342		43,098
Total	$	23,105,408	$	253,348	$	132,251	$	9,366	$	23,237,659	$	262,714

The allowance for loan losses and recorded investment of the related loans by portfolio segment for each measurement method at December 31, 2022 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	$	14,152,202	$	127,566	$	60,297	$	4,020	$	14,212,499	$	131,586
Commercial real estate	4,590,207		56,098		16,570		1,550		4,606,777		57,648
Loans to individuals	3,692,944		46,470		44,930		—		3,737,874		46,470
Total	$	22,435,353	$	230,134	$	121,797	$	5,570	$	22,557,150	$	235,704

Schedule of Credit Quality Indicators [Table Text Block]

The following table summarizes the Company’s loan portfolio at June 30, 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:
Energy
Pass	$	120,233	$	99,929	$	50,910	$	8,713	$	10,528	$	10,884	$	3,185,817	$	—	$	3,487,014
Accruing Substandard	—		—		—		—		651		1,050		—		—		1,701
Nonaccrual	—		—		—		—		—		117		19,920		—		20,037
Total energy	120,233		99,929		50,910		8,713		11,179		12,051		3,205,737		—		3,508,752
Loans charged-off, year-to-date	—		—		—		—		—		—		—		—		—
Healthcare
Pass	357,976		857,991		584,067		465,489		367,300		958,933		275,267		17		3,867,040
Special Mention	—		—		18,722		6,986		14,025		32,123		980		—		72,836
Accruing Substandard	—		540		—		—		—		12,518		1,700		—		14,758
Nonaccrual	—		—		—		—		25,967		10,786		—		—		36,753
Total healthcare	357,976		858,531		602,789		472,475		407,292		1,014,360		277,947		17		3,991,387
Loans charged-off, year-to-date	—		—		—		—		—		—		—		—		—
Services
Pass	378,254		681,854		461,897		262,276		158,543		759,638		820,662		607		3,523,731
Special Mention	—		18,244		252		180		623		2,171		3,963		—		25,433
Accruing Substandard	—		629		836		1,756		2,556		3,372		22,259		56		31,464
Nonaccrual	—		—		4,137		404		—		—		—		—		4,541
Total services	378,254		700,727		467,122		264,616		161,722		765,181		846,884		663		3,585,169
Loans charged-off, year-to-date	—		—		882		—		—		—		1,899		—		2,781
General business
Pass	443,873		624,377		292,674		158,127		158,780		339,584		1,327,452		2,352		3,347,219
Special Mention	898		3,461		7,449		44		114		1,485		15,563		—		29,014
Accruing Substandard	—		41,341		2,931		46		—		6,072		10,629		10		61,029
Nonaccrual	—		—		—		—		14		60		11,843		29		11,946
Total general business	444,771		669,179		303,054		158,217		158,908		347,201		1,365,487		2,391		3,449,208
Loans charged-off, year-to-date	—		—		—		2		—		12		4		10		28
Total commercial	1,301,234		2,328,366		1,423,875		904,021		739,101		2,138,793		5,696,055		3,071		14,534,516
Commercial real estate:
Pass	281,559		1,541,831		1,173,425		491,657		543,242		790,115		117,939		—		4,939,768
Special Mention	—		—		—		—		—		13,638		—		—		13,638
Nonaccrual	—		—		—		—		7,343		10,052		—		—		17,395
Total commercial real estate	281,559		1,541,831		1,173,425		491,657		550,585		813,805		117,939		—		4,970,801
Loans charged-off, year-to-date	—		—		—		—		—		6,208		—		—		6,208

	Origination Year
	2023		2022		2021		2020		2019		Prior		Revolving Loans		Revolving Loans Converted to Term Loans		Total
Loans to individuals:
Residential mortgage
Pass	190,406		339,049		359,330		363,831		59,080		267,776		356,384		22,218		1,958,074
Special Mention	—		246		—		1,347		—		355		3,388		—		5,336
Accruing Substandard	—		—		—		—		—		54		253		—		307
Nonaccrual	—		1,147		2,280		2,828		729		20,042		2,228		719		29,973
Total residential mortgage	190,406		340,442		361,610		368,006		59,809		288,227		362,253		22,937		1,993,690
Loans charged-off, year-to-date	—		—		7		—		—		4		1		—		12
Residential mortgage guaranteed by U.S. government agencies
Pass	—		1,184		2,089		5,872		7,690		157,862		—		—		174,697
Nonaccrual	—		—		—		299		641		10,533		—		—		11,473
Total residential mortgage guaranteed by U.S. government agencies	—		1,184		2,089		6,171		8,331		168,395		—		—		186,170
Personal:
Pass	83,233		230,418		175,862		151,387		130,574		199,122		575,095		249		1,545,940
Special Mention	—		47		82		49		7		3		6,056		—		6,244
Accruing Substandard	—		—		—		—		160		—		5		—		165
Nonaccrual	—		36		5		45		5		14		28		—		133
Total personal	83,233		230,501		175,949		151,481		130,746		199,139		581,184		249		1,552,482
Loans charged-off, year-to-date	—		43		40		16		—		2,584		4		1		2,688
Total loans to individuals	273,639		572,127		539,648		525,658		198,886		655,761		943,437		23,186		3,732,342
Total loans	$	1,856,432	$	4,442,324	$	3,136,948	$	1,921,336	$	1,488,572	$	3,608,359	$	6,757,431	$	26,257	$	23,237,659

The following table summarizes the Company's loan portfolio at December 31, 2022 by the risk grade categories and vintage (in thousands): 

	Origination Year
	2022		2021		2020		2019		2018		Prior		Revolving Loans		Revolving Loans Converted to Term Loans		Total
Commercial:
Energy
Pass	$	157,745	$	76,951	$	30,284	$	12,783	$	5,992	$	4,980	$	3,104,906	$	—	$	3,393,641
Accruing Substandard	—		—		—		664		385		683		28,018		—		29,750
Nonaccrual	—		—		—		—		—		159		1,240		—		1,399
Total energy	157,745		76,951		30,284		13,447		6,377		5,822		3,134,164		—		3,424,790
Healthcare
Pass	932,097		604,886		476,854		404,204		464,989		618,163		245,898		20		3,747,111
Special Mention	—		—		—		20,071		—		18,859		4		—		38,934
Accruing Substandard	—		—		—		—		—		14,304		3,634		—		17,938
Nonaccrual	—		—		—		26,480		6,373		8,181		—		—		41,034
Total healthcare	932,097		604,886		476,854		450,755		471,362		659,507		249,536		20		3,845,017
Services
Pass	821,785		496,510		286,085		193,481		156,736		696,300		722,371		639		3,373,907
Special Mention	502		5,139		989		771		894		1,345		8,668		—		18,308
Accruing Substandard	—		—		—		2,459		43		2,789		17,665		122		23,078
Nonaccrual	—		5,570		449		—		—		2,389		7,820		—		16,228
Total services	822,287		507,219		287,523		196,711		157,673		702,823		756,524		761		3,431,521
General business
Pass	725,894		361,839		198,274		172,878		139,140		283,694		1,570,536		2,329		3,454,584
Special Mention	17,759		13,065		208		71		7		2,291		7,094		26		40,521
Accruing Substandard	—		2,169		66		4,130		4,680		3,287		94		4		14,430
Nonaccrual	—		—		1,052		14		72		5		485		8		1,636
Total general business	743,653		377,073		199,600		177,093		143,899		289,277		1,578,209		2,367		3,511,171
Total commercial	2,655,782		1,566,129		994,261		838,006		779,311		1,657,429		5,718,433		3,148		14,212,499
Commercial real estate:
Pass	1,188,483		1,158,002		552,616		641,102		247,625		633,304		161,616		—		4,582,748
Accruing Substandard	—		—		—		7,459		—		—		—		—		7,459
Nonaccrual	—		—		—		—		—		16,570		—		—		16,570
Total commercial real estate	1,188,483		1,158,002		552,616		648,561		247,625		649,874		161,616		—		4,606,777

	Origination Year
	2022		2021		2020		2019		2018		Prior		Revolving Loans		Revolving Loans Converted to Term Loans		Total
Loans to individuals:
Residential mortgage
Pass	354,497		373,190		393,002		63,142		40,525		260,625		352,126		22,176		1,859,283
Special Mention	—		81		42		—		142		388		527		87		1,267
Accruing Substandard	—		—		187		—		—		138		117		1		443
Nonaccrual	32		1,656		2,717		362		1,904		20,139		2,216		765		29,791
Total residential mortgage	354,529		374,927		395,948		63,504		42,571		281,290		354,986		23,029		1,890,784
Residential mortgage guaranteed by U.S. government agencies
Pass	289		2,254		9,000		10,722		17,244		191,426		—		—		230,935
Nonaccrual	—		—		299		1,460		2,319		10,927		—		—		15,005
Total residential mortgage guaranteed by U.S. government agencies	289		2,254		9,299		12,182		19,563		202,353		—		—		245,940
Personal:
Pass	254,497		193,095		154,887		172,114		68,871		201,278		549,187		332		1,594,261
Special Mention	47		28		40		12		17		—		6,003		4		6,151
Accruing Substandard	—		444		—		160		—		—		—		—		604
Nonaccrual	38		7		12		22		14		18		23		—		134
Total personal	254,582		193,574		154,939		172,308		68,902		201,296		555,213		336		1,601,150
Total loans to individuals	609,400		570,755		560,186		247,994		131,036		684,939		910,199		23,365		3,737,874
Total loans	$	4,453,665	$	3,294,886	$	2,107,063	$	1,734,561	$	1,157,972	$	2,992,242	$	6,790,248	$	26,513	$	22,557,150

Financing Receivable, Nonaccrual [Table Text Block]

A summary of nonaccruing loans at June 30, 2023 follows (in thousands): 

	As of June 30, 2023
	Total		With No Allowance		With Allowance		Related Allowance
Commercial:
Energy	$	20,037	$	20,037	$	—	$	—
Healthcare	36,753		36,753		—		—
Services	4,541		404		4,137		3,218
General business	11,946		7,348		4,598		4,598
Total commercial	73,277		64,542		8,735		7,816
Commercial real estate	17,395		7,504		9,891		1,550
Loans to individuals:
Residential mortgage	29,973		29,973		—		—
Residential mortgage guaranteed by U.S. government agencies	11,473		11,473		—		—
Personal	133		133		—		—
Total loans to individuals	41,579		41,579		—		—
Total	$	132,251	$	113,625	$	18,626	$	9,366

A summary of nonaccruing loans at December 31, 2022 follows (in thousands): 

	As of December 31, 2022
	Total		With No Allowance		With Allowance		Related Allowance
Commercial:
Energy	$	1,399	$	1,399	$	—	$	—
Healthcare	41,034		34,661		6,373		946
Services	16,228		7,835		8,393		3,074
General business	1,636		1,636		—		—
Total commercial	60,297		45,531		14,766		4,020
Commercial real estate	16,570		393		16,177		1,550
Loans to individuals:
Residential mortgage	29,791		29,791		—		—
Residential mortgage guaranteed by U.S. government agencies	15,005		15,005		—		—
Personal	134		134		—		—
Total loans to individuals	44,930		44,930		—		—
Total	$	121,797	$	90,854	$	30,943	$	5,570

Summary of Loans by Aging Status [Table Text Block]

A summary of loans currently performing and past due as of June 30, 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:
Energy	$	3,508,752	$	—	$	—	$	—	$	3,508,752	$	—
Healthcare	3,959,317		—		—		32,070		3,991,387		—
Services	3,582,538		2,172		55		404		3,585,169		—
General business	3,444,191		4,893		118		6		3,449,208		6
Total commercial	14,494,798		7,065		173		32,480		14,534,516		6
Commercial real estate	4,963,458		—		—		7,343		4,970,801		—
Loans to individuals:
Residential mortgage	1,976,973		10,537		2,850		3,330		1,993,690		54
Residential mortgage guaranteed by U.S. government agencies	75,333		30,504		18,302		62,031		186,170		55,782
Personal	1,548,084		3,185		1,009		204		1,552,482		160
Total loans to individuals	3,600,390		44,226		22,161		65,565		3,732,342		55,996
Total	$	23,058,646	$	51,291	$	22,334	$	105,388	$	23,237,659	$	56,002

A summary of loans currently performing and past due as of December 31, 2022 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:
Energy	$	3,424,766	$	24	$	—	$	—	$	3,424,790	$	—
Healthcare	3,812,164		5,914		26,480		459		3,845,017		—
Services	3,423,042		1,060		2,461		4,958		3,431,521		—
General business	3,509,094		257		1,424		396		3,511,171		396
Total commercial	14,169,066		7,255		30,365		5,813		14,212,499		396
Commercial real estate	4,606,029		531		—		217		4,606,777		—
Loans to individuals:
Residential mortgage	1,872,155		10,632		1,828		6,169		1,890,784		114
Residential mortgage guaranteed by U.S. government agencies	108,019		36,119		19,400		82,402		245,940		75,604
Personal	1,600,595		502		21		32		1,601,150		—
Total loans to individuals	3,580,769		47,253		21,249		88,603		3,737,874		75,718
Total	$	22,355,864	$	55,039	$	51,614	$	94,633	$	22,557,150	$	76,114