Loans and Allowances for Credit Losses (Tables)

9 Months Ended

Sep. 30, 2021

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):

	September 30, 2021								December 31, 2020
	Fixed Rate		Variable Rate		Non-accrual		Total		Fixed Rate		Variable Rate		Non-accrual		Total
Commercial	$	3,337,034	$	8,757,432	$	80,674	$	12,175,140	$	3,174,203	$	9,736,173	$	167,159	$	13,077,535
Commercial real estate	968,223		3,127,446		21,223		4,116,892		1,047,486		3,623,806		27,246		4,698,538
Paycheck protection program	536,052		—		—		536,052		1,682,310		—		—		1,682,310
Loans to individuals	2,086,645		1,393,157		40,050		3,519,852		2,174,874		1,333,975		40,288		3,549,137
Total	$	6,927,954	$	13,278,035	$	141,947	$	20,347,936	$	8,078,873	$	14,693,954	$	234,693	$	23,007,520

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
	September 30, 2021
	Commercial		Commercial Real Estate		Paycheck Protection Program		Loans to Individuals		Nonspecific Allowance		Total
Allowance for loan losses:
Beginning balance	$	198,303	$	70,540	$	—	$	43,047	$	—	$	311,890
Provision for loan losses	(15,996)		(9,418)		—		(1,981)		—		(27,395)
Loans charged off	(6,979)		(1,422)		—		(1,183)		—		(9,584)
Recoveries of loans previously charged off	832		228		—		709		—		1,769
Ending Balance	$	176,160	$	59,928	$	—	$	40,592	—		$	276,680
Allowance for off-balance sheet credit risk from unfunded loan commitments:
Beginning balance	$	10,094	$	12,348	$	—	$	1,845	$	—	$	24,287
Provision for off-balance sheet credit risk	2,772		2,294		—		(114)		—		4,952
Ending Balance	$	12,866	$	14,642	$	—	$	1,731	$	—	$	29,239

	Nine Months Ended
	September 30, 2021
	Commercial		Commercial Real Estate		Paycheck Protection Program		Loans to Individuals		Nonspecific Allowance		Total
Allowance for loan losses:
Beginning balance	$	254,934	$	86,558	$	—	$	47,148	$	—	$	388,640
Provision for loan losses	(44,331)		(24,579)		—		(5,319)		—		(74,229)
Loans charged off	(38,826)		(2,485)		—		(3,482)		—		(44,793)
Recoveries	4,383		434		—		2,245		—		7,062
Ending balance	$	176,160	$	59,928	$	—	$	40,592	$	—	$	276,680
Allowance for off-balance sheet credit risk from unfunded loan commitments:
Beginning balance	$	14,422	$	20,571	$	—	$	1,928	$	—	$	36,921
Transition adjustment	—		—		—		—		—		—
Beginning balance, adjusted	14,422		20,571		—		1,928		—		36,921
Provision for off-balance sheet credit losses	(1,556)		(5,929)		—		(197)		—		(7,682)
Ending balance	$	12,866	$	14,642	$	—	$	1,731	$	—	$	29,239

	Three Months Ended
	September 30, 2020
	Commercial		Commercial Real Estate		Paycheck Protection Program		Loans to Individuals		Nonspecific Allowance		Total
Allowance for loan losses:
Beginning balance	$	310,422	$	68,756	$	—	$	56,419	$	—	$	435,597
Provision for loan losses	2,108		3,118		—		1,383		—		6,609
Loans charged off	(25,319)		(413)		—		(929)		—		(26,661)
Recoveries of loans previously charged off	3,066		114		—		1,052		—		4,232
Ending Balance	$	290,277	$	71,575	$	—	$	57,925	—		$	419,777
Allowance for off-balance sheet credit risk from unfunded loan commitments:
Beginning balance	$	14,582	$	16,419	$	—	$	1,918	$	—	$	32,919
Transition adjustment	—		—		—		—		—		—
Beginning balance, adjusted	14,582		16,419		—		1,918		—		32,919
Provision for off-balance sheet credit risk	(2,618)		(2,426)		—		94		—		(4,950)
Ending Balance	$	11,964	$	13,993	$	—	$	2,012	—		$	27,969

	Nine Months Ended
	September 30, 2020
	Commercial		Commercial Real Estate		Paycheck Protection Program		Loans to Individuals		Nonspecific Allowance		Total
Allowance for loan losses:
Beginning balance	$	118,187	$	51,805	$	—	$	23,572	$	17,195	$	210,759
Transition adjustment	33,681		(4,620)		—		13,943		(17,195)		25,809
Beginning balance, adjusted	151,868		47,185		—		37,515		—		236,568
Provision for loan losses	190,984		25,454		—		20,500		—		236,938
Loans charged off	(56,421)		(1,300)		—		(3,427)		—		(61,148)
Recoveries of loans previously charged off	3,846		236		—		3,337		—		7,419
Ending Balance	$	290,277	$	71,575	$	—	$	57,925	—		$	419,777
Allowance for off-balance sheet credit risk from unfunded loan commitments:
Beginning balance	$	1,434	$	107	$	—	$	44	$	—	$	1,585
Transition adjustment	10,144		11,660		—		1,748		—		23,552
Beginning balance, adjusted	11,578		11,767		—		1,792		—		25,137
Provision for off-balance sheet credit risk	386		2,226		—		220		—		2,832
Ending Balance	$	11,964	$	13,993	$	—	$	2,012	—		$	27,969

Changes in our reasonable and supportable forecasts of macroeconomic variables, primarily due to continued strength in commodity prices and a continued optimistic outlook for economic growth in GDP and labor markets resulted in a $12.3 million negative provision for credit losses related to lending activities during the third quarter of 2021. Changes in the loan portfolio characteristics, including specific impairment and losses, loan balances, risk grading and changes in payment profile resulted in a $10.1 million negative provision for credit losses related to lending activities.

The allowance for loan losses and recorded investment of the related loans by portfolio segment for each measurement method at September 30, 2021 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	$	12,094,466	$	168,325	$	80,674	$	7,835	$	12,175,140	$	176,160
Commercial real estate	4,095,669		57,579		21,223		2,349		4,116,892		59,928
Paycheck protection program	536,052		—		—		—		536,052		—
Loans to individuals	3,479,802		40,592		40,050		—		3,519,852		40,592
Total	$	20,205,989	$	266,496	$	141,947	$	10,184	$	20,347,936	$	276,680

The allowance for loan losses and recorded investment of the related loans by portfolio segment for each measurement method at December 31, 2020 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	$	12,910,376	$	235,882	$	167,159	$	19,052	$	13,077,535	$	254,934
Commercial real estate	4,671,292		83,169		27,246		3,389		4,698,538		86,558
Paycheck protection program	1,682,310		—		—		—		1,682,310		—
Loans to individuals	3,508,849		47,148		40,288		—		3,549,137		47,148
Total	$	22,772,827	$	366,199	$	234,693	$	22,441	$	23,007,520	$	388,640

Schedule of Credit Quality Indicators [Table Text Block]

The following table summarizes the Company’s loan portfolio at September 30, 2021 by the risk grade categories and vintage (in thousands): 

	Origination Year
	2021		2020		2019		2018		2017		Prior		Revolving Loans		Revolving Loans Converted to Term Loans		Total
Commercial:
Energy
Pass	$	154,735	$	38,019	$	33,135	$	14,559	$	4,987	$	19,327	$	2,306,845	$	—	$	2,571,607
Special Mention	565		1,607		—		—		—		—		750		—		2,922
Accruing Substandard	—		23,065		1,230		1,100		—		6		168,629		—		194,030
Nonaccrual	—		20,722		1,570		—		—		9,409		13,799		—		45,500
Total energy	155,300		83,413		35,935		15,659		4,987		28,742		2,490,023		—		2,814,059
Healthcare
Pass	383,462		593,123		576,153		521,156		329,791		720,489		149,119		—		3,273,293
Special Mention	6,883		—		15,746		—		5,834		—		5		—		28,468
Accruing Substandard	—		—		27,292		7,304		—		10,775		—		—		45,371
Nonaccrual	—		—		—		—		—		—		509		—		509
Total healthcare	390,345		593,123		619,191		528,460		335,625		731,264		149,633		—		3,347,641
Services
Pass	430,099		501,607		334,009		298,665		240,892		847,065		584,197		415		3,236,949
Special Mention	453		412		2,779		49		3,318		11,085		2,027		203		20,326
Accruing Substandard	26		76		10,575		16,418		1,839		5,603		5,896		—		40,433
Nonaccrual	—		4,529		—		230		14,220		6,232		503		—		25,714
Total services	430,578		506,624		347,363		315,362		260,269		869,985		592,623		618		3,323,422
General business
Pass	457,490		246,333		295,089		212,899		188,407		230,442		1,002,036		2,025		2,634,721
Special Mention	232		1,380		66		1,469		3,937		318		8,697		—		16,099
Accruing Substandard	365		1,230		2,458		7,961		8,694		6,906		2,633		—		30,247
Nonaccrual	—		1,582		4,235		1,240		770		531		462		131		8,951
Total general business	458,087		250,525		301,848		223,569		201,808		238,197		1,013,828		2,156		2,690,018
Total commercial	1,434,310		1,433,685		1,304,337		1,083,050		802,689		1,868,188		4,246,107		2,774		12,175,140
Commercial real estate:
Pass	374,519		805,102		1,104,404		466,778		336,206		822,068		140,050		33		4,049,160
Special Mention	—		—		—		6,683		10,943		6,760		—		—		24,386
Accruing Substandard	—		—		—		13,288		4,480		4,355		—		—		22,123
Nonaccrual	—		—		8,244		—		—		12,979		—		—		21,223
Total commercial real estate	374,519		805,102		1,112,648		486,749		351,629		846,162		140,050		33		4,116,892

	Origination Year
	2021		2020		2019		2018		2017		Prior		Revolving Loans		Revolving Loans Converted to Term Loans		Total
Paycheck protection program:
Pass	450,844		85,208		—		—		—		—		—		—		536,052
Total paycheck protection program	450,844		85,208		—		—		—		—		—		—		536,052
Loans to individuals:
Residential mortgage
Pass	325,951		478,460		93,556		67,648		80,208		333,932		313,255		22,305		1,715,315
Special Mention	—		—		82		13		—		283		248		—		626
Accruing Substandard	—		—		—		—		—		126		479		23		628
Nonaccrual	758		1,446		341		1,051		688		23,457		2,097		836		30,674
Total residential mortgage	326,709		479,906		93,979		68,712		80,896		357,798		316,079		23,164		1,747,243
Residential mortgage guaranteed by U.S. government agencies
Pass	348		10,308		24,350		30,941		35,341		266,510		—		—		367,798
Nonaccrual	—		—		82		244		143		8,719		—		—		9,188
Total residential mortgage guaranteed by U.S. government agencies	348		10,308		24,432		31,185		35,484		275,229		—		—		376,986
Personal:
Pass	154,436		199,604		183,461		69,075		97,119		136,837		553,702		887		1,395,121
Special Mention	14		15		23		10		—		45		5		—		112
Accruing Substandard	—		—		180		1		—		—		21		—		202
Nonaccrual	19		9		10		25		38		61		26		—		188
Total personal	154,469		199,628		183,674		69,111		97,157		136,943		553,754		887		1,395,623
Total loans to individuals	481,526		689,842		302,085		169,008		213,537		769,970		869,833		24,051		3,519,852
Total loans	$	2,741,199	$	3,013,837	$	2,719,070	$	1,738,807	$	1,367,855	$	3,484,320	$	5,255,990	$	26,858	$	20,347,936

The following table summarizes the Company’s loan portfolio at December 31, 2020 by the risk grade categories and vintage (in thousands): 

	Origination Year
	2020		2019		2018		2017		2016		Prior		Revolving Loans		Revolving Loans Converted to Term Loans		Total
Commercial:
Energy
Pass	$	112,614	$	51,863	$	89,346	$	7,178	$	1,148	$	7,956	$	2,548,663	$	—	$	2,818,768
Special Mention	—		—		—		—		—		—		202,590		—		202,590
Accruing Substandard	24,000		1,363		1,453		—		12,667		—		283,294		—		322,777
Nonaccrual	21,076		2,607		—		—		—		21,064		80,312		—		125,059
Total energy	157,690		55,833		90,799		7,178		13,815		29,020		3,114,859		—		3,469,194
Healthcare
Pass	536,745		615,221		638,302		422,834		234,399		658,286		147,132		—		3,252,919
Special Mention	—		27,500		—		—		—		8,282		5		—		35,787
Accruing Substandard	—		—		1,191		929		132		11,387		—		—		13,639
Nonaccrual	—		18		183		—		—		2,935		509		—		3,645
Total healthcare	536,745		642,739		639,676		423,763		234,531		680,890		147,646		—		3,305,990
Services
Pass	534,853		436,384		372,867		307,374		373,785		683,936		665,491		682		3,375,372
Special Mention	150		9,057		389		291		2,038		2,000		3,063		—		16,988
Accruing Substandard	429		6,380		26,008		6,027		5,030		7,954		38,797		—		90,625
Nonaccrual	4,833		448		—		12,590		1,049		6,138		540		—		25,598
Total services	540,265		452,269		399,264		326,282		381,902		700,028		707,891		682		3,508,583
General business
Pass	419,756		394,985		310,273		236,222		103,987		186,600		1,055,878		2,316		2,710,017
Special Mention	197		4,519		9,713		7,803		2,511		3,159		2,483		19		30,404
Accruing Substandard	1,432		3,069		6,694		10,935		10,042		3,729		4,449		140		40,490
Nonaccrual	1,675		3,728		4,863		1,436		530		107		477		41		12,857
Total general business	423,060		406,301		331,543		256,396		117,070		193,595		1,063,287		2,516		2,793,768
Total commercial	1,657,760		1,557,142		1,461,282		1,013,619		747,318		1,603,533		5,033,683		3,198		13,077,535
Commercial real estate:
Pass	725,577		1,211,338		954,226		489,193		314,899		722,475		223,131		38		4,640,877
Special Mention	—		—		259		12,311		2,725		5,831		—		—		21,126
Accruing Substandard	—		—		—		4,410		—		4,852		27		—		9,289
Nonaccrual	—		8,300		—		232		7,468		11,246		—		—		27,246
Total commercial real estate	725,577		1,219,638		954,485		506,146		325,092		744,404		223,158		38		4,698,538

	Origination Year
	2020		2019		2018		2017		2016		Prior		Revolving Loans		Revolving Loans Converted to Term Loans		Total
Paycheck protection program:
Pass	1,682,310		—		—		—		—		—		—		—		1,682,310
Total paycheck protection program	1,682,310		—		—		—		—		—		—		—		1,682,310
Loans to individuals:
Residential mortgage
Pass	564,325		149,832		120,875		124,930		158,801		348,292		335,259		24,553		1,826,867
Special Mention	33		11		2,094		—		59		318		950		10		3,475
Accruing Substandard	—		—		51		—		—		34		272		76		433
Nonaccrual	648		104		1,658		784		2,010		22,415		3,835		774		32,228
Total residential mortgage	565,006		149,947		124,678		125,714		160,870		371,059		340,316		25,413		1,863,003
Residential mortgage guaranteed by U.S. government agencies
Pass	4,859		33,880		34,464		43,099		58,264		226,380		—		—		400,946
Nonaccrual	—		—		545		—		309		6,887		—		—		7,741
Total residential mortgage guaranteed by U.S. government agencies	4,859		33,880		35,009		43,099		58,573		233,267		—		—		408,687
Personal:
Pass	219,873		200,580		76,246		100,229		64,104		102,126		510,571		1,510		1,275,239
Special Mention	39		55		66		—		469		31		965		—		1,625
Accruing Substandard	11		214		10		—		—		—		29		—		264
Nonaccrual	28		17		57		73		50		49		45		—		319
Total personal	219,951		200,866		76,379		100,302		64,623		102,206		511,610		1,510		1,277,447
Total loans to individuals	789,816		384,693		236,066		269,115		284,066		706,532		851,926		26,923		3,549,137
Total loans	$	4,855,463	$	3,161,473	$	2,651,833	$	1,788,880	$	1,356,476	$	3,054,469	$	6,108,767	$	30,159	$	23,007,520

Financing Receivable, Nonaccrual [Table Text Block]

A summary of nonaccruing loans at September 30, 2021 follows (in thousands): 

	As of September 30, 2021
	Total		With No Allowance		With Allowance		Related Allowance
Commercial:
Energy	$	45,500	$	40,998	$	4,502	$	2,417
Healthcare	509		509		—		—
Services	25,714		18,512		7,202		4,918
General business	8,951		5,526		3,425		500
Total commercial	80,674		65,545		15,129		7,835
Commercial real estate	21,223		12,979		8,244		2,349
Loans to individuals:
Residential mortgage	30,674		30,674		—		—
Residential mortgage guaranteed by U.S. government agencies	9,188		9,188		—		—
Personal	188		188		—		—
Total loans to individuals	40,050		40,050		—		—
Total	$	141,947	$	118,574	$	23,373	$	10,184

A summary of nonaccruing loans at December 31, 2020 follows (in thousands): 

	As of December 31, 2020
	Total		With No Allowance		With Allowance		Related Allowance
Commercial:
Energy	$	125,059	$	76,633	$	48,426	$	16,478
Healthcare	3,645		3,645		—		—
Services	25,598		20,810		4,788		2,574
General business	12,857		12,857		—		—
Total commercial	167,159		113,945		53,214		19,052
Commercial real estate	27,246		13,645		13,601		3,389
Loans to individuals:
Residential mortgage	32,228		32,228		—		—
Residential mortgage guaranteed by U.S. government agencies	7,741		7,741		—		—
Personal	319		319		—		—
Total loans to individuals	40,288		40,288		—		—
Total	$	234,693	$	167,878	$	66,815	$	22,441

Summary of Loans by Aging Status [Table Text Block]

A summary of loans currently performing and past due as of September 30, 2021 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	$	2,803,488	$	—	$	—	$	10,571	$	2,814,059	$	—
Healthcare	3,346,740		404		—		497		3,347,641		—
Services	3,309,658		3,092		1,648		9,024		3,323,422		—
General business	2,678,878		1,732		1,821		7,587		2,690,018		200
Total commercial	12,138,764		5,228		3,469		27,679		12,175,140		200
Commercial real estate	4,105,791		1,505		—		9,596		4,116,892		—
Paycheck protection program	536,052		—		—		—		536,052		—
Loans to individuals:
Residential mortgage	1,731,942		6,147		2,269		6,885		1,747,243		23
Residential mortgage guaranteed by U.S. government agencies	204,901		35,894		18,028		118,163		376,986		111,835
Personal	1,395,445		74		37		67		1,395,623		—
Total loans to individuals	3,332,288		42,115		20,334		125,115		3,519,852		111,858
Total	$	20,112,895	$	48,848	$	23,803	$	162,390	$	20,347,936	$	112,058

A summary of loans currently performing and past due as of December 31, 2020 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	$	3,410,995	$	12,735	$	4,050	$	41,414	$	3,469,194	$	—
Healthcare	3,302,345		—		—		3,645		3,305,990		—
Services	3,489,423		3,278		177		15,705		3,508,583		326
General business	2,776,038		1,206		6,277		10,247		2,793,768		4,495
Total commercial	12,978,801		17,219		10,504		71,011		13,077,535		4,821
Commercial real estate	4,672,279		276		5,310		20,673		4,698,538		5,126
Paycheck protection program	1,682,310		—		—		—		1,682,310		—
Loans to individuals:
Residential mortgage	1,849,304		5,812		837		7,050		1,863,003		181
Residential mortgage guaranteed by U.S. government agencies	262,102		41,389		22,041		83,155		408,687		78,349
Personal	1,273,702		3,317		90		338		1,277,447		241
Total loans to individuals	3,385,108		50,518		22,968		90,543		3,549,137		78,771
Total	$	22,718,498	$	68,013	$	38,782	$	182,227	$	23,007,520	$	88,718