Loans and Allowances for Credit Losses (Tables)

3 Months Ended

Mar. 31, 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):

	March 31, 2021								December 31, 2020
	Fixed Rate		Variable Rate		Non-accrual		Total		Fixed Rate		Variable Rate		Non-accrual		Total
Commercial	$	3,264,973	$	9,245,738	$	147,073	$	12,657,784	$	3,174,203	$	9,736,173	$	167,159	$	13,077,535
Commercial real estate	1,019,531		3,456,573		27,243		4,503,347		1,047,486		3,623,806		27,246		4,698,538
Paycheck protection program	1,848,550		—		—		1,848,550		1,682,310		—		—		1,682,310
Loans to individuals	2,146,671		1,335,792		41,703		3,524,166		2,174,874		1,333,975		40,288		3,549,137
Total	$	8,279,725	$	14,038,103	$	216,019	$	22,533,847	$	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
	March 31, 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	(9,893)		(4,579)		—		(7,298)		—		(21,770)
Loans charged off	(15,345)		(263)		—		(1,297)		—		(16,905)
Recoveries of loans previously charged off	1,676		30		—		731		—		2,437
Ending Balance	$	231,372	$	81,746	$	—	$	39,284	—		$	352,402
Allowance for off-balance sheet credit risk from unfunded loan commitments:
Beginning balance	$	14,422	$	20,571	$	—	$	1,928	$	—	$	36,921
Provision for off-balance sheet credit risk	(1,686)		(2,273)		—		(85)		—		(4,044)
Ending Balance	$	12,736	$	18,298	$	—	$	1,843	$	—	$	32,877

	Three Months Ended
	March 31, 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	77,723		5,115		—		13,126		—		95,964
Loans charged off	(16,615)		(886)		—		(1,416)		—		(18,917)
Recoveries of loans previously charged off	462		47		—		1,187		—		1,696
Ending Balance	$	213,438	$	51,461	$	—	$	50,412	—		$	315,311
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	2,462		808		—		107		—		3,377
Ending Balance	$	14,040	$	12,575	$	—	$	1,899	—		$	28,514

Changes in our reasonable and supportable forecasts of macroeconomic variables, primarily due to the anticipated impact of the on-going COVID-19 pandemic, and other assumptions, resulted in a $31.1 million reduction in the allowance for lending activities during the first quarter of 2021. Changes in the loan portfolio characteristics, including specific impairment and losses, loan balances and risk grading resulted in a $5.2 million increase in the allowance for lending activities.

The allowance for loan losses and recorded investment of the related loans by portfolio segment for each measurement method at March 31, 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	$	12,510,711	$	214,711	$	147,073	$	16,661	$	12,657,784	$	231,372
Commercial real estate	4,476,104		78,356		27,243		3,390		4,503,347		81,746
Paycheck protection program	1,848,550		—		—		—		1,848,550		—
Loans to individuals	3,482,463		39,284		41,703		—		3,524,166		39,284
Total	$	22,317,828	$	332,351	$	216,019	$	20,051	$	22,533,847	$	352,402

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 March 31, 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	$	63,102	$	81,658	$	51,881	$	78,812	$	6,731	$	8,019	$	2,388,115	$	—	$	2,678,318
Special Mention	17,000		—		—		—		—		—		144,976		—		161,976
Accruing Substandard	—		24,051		1,319		1,337		—		11,922		221,765		—		260,394
Nonaccrual	—		21,008		2,488		—		—		13,340		64,964		—		101,800
Total energy	80,102		126,717		55,688		80,149		6,731		33,281		2,819,820		—		3,202,488
Healthcare
Pass	114,646		570,755		617,791		615,371		394,541		780,397		153,973		—		3,247,474
Special Mention	—		—		—		—		—		504		5		—		509
Accruing Substandard	—		—		27,500		1,032		—		11,056		—		—		39,588
Nonaccrual	—		—		18		—		—		2,660		509		—		3,187
Total healthcare	114,646		570,755		645,309		616,403		394,541		794,617		154,487		—		3,290,758
Services
Pass	182,186		542,579		381,122		327,241		300,688		1,005,483		574,095		627		3,314,021
Special Mention	—		138		1,446		1,008		7		1,844		1,971		—		6,414
Accruing Substandard	—		421		11,238		18,435		5,288		9,471		28,627		—		73,480
Nonaccrual	—		4,732		448		766		14,369		7,033		685		—		28,033
Total services	182,186		547,870		394,254		347,450		320,352		1,023,831		605,378		627		3,421,948
General business
Pass	118,267		361,002		370,674		274,644		209,218		297,857		1,032,658		2,305		2,666,625
Special Mention	—		189		4,850		3,401		7,469		1,781		4,903		—		22,593
Accruing Substandard	—		1,392		2,575		12,901		8,738		10,287		3,408		18		39,319
Nonaccrual	—		1,675		3,887		5,893		1,430		565		558		45		14,053
Total general business	118,267		364,258		381,986		296,839		226,855		310,490		1,041,527		2,368		2,742,590
Total commercial	495,201		1,609,600		1,477,237		1,340,841		948,479		2,162,219		4,621,212		2,995		12,657,784
Commercial real estate:
Pass	73,306		812,635		1,215,895		796,047		430,066		951,180		163,737		37		4,442,903
Special Mention	—		—		—		3,201		14,110		6,900		—		—		24,211
Accruing Substandard	—		—		—		—		4,454		4,509		27		—		8,990
Nonaccrual	—		—		8,300		—		—		18,943		—		—		27,243
Total commercial real estate	73,306		812,635		1,224,195		799,248		448,630		981,532		163,764		37		4,503,347

	Origination Year
	2021		2020		2019		2018		2017		Prior		Revolving Loans		Revolving Loans Converted to Term Loans		Total
Paycheck protection program:
Pass	544,128		1,304,422		—		—		—		—		—		—		1,848,550
Total paycheck protection program	544,128		1,304,422		—		—		—		—		—		—		1,848,550
Loans to individuals:
Residential mortgage
Pass	124,830		534,781		119,866		100,259		103,645		433,347		318,319		23,567		1,758,614
Special Mention	—		22		—		1,851		—		3,429		204		74		5,580
Accruing Substandard	—		—		—		—		—		—		400		—		400
Nonaccrual	—		626		124		1,913		728		24,658		4,013		822		32,884
Total residential mortgage	124,830		535,429		119,990		104,023		104,373		461,434		322,936		24,463		1,797,478
Residential mortgage guaranteed by U.S. government agencies
Pass	—		7,101		32,171		35,189		45,744		291,282		—		—		411,487
Nonaccrual	—		—		—		873		—		7,691		—		—		8,564
Total residential mortgage guaranteed by U.S. government agencies	—		7,101		32,171		36,062		45,744		298,973		—		—		420,051
Personal:
Pass	44,298		215,962		192,533		73,230		97,757		155,714		524,716		1,370		1,305,580
Special Mention	—		28		14		21		2		474		12		—		551
Accruing Substandard	—		—		215		—		—		17		19		—		251
Nonaccrual	—		2		11		60		73		81		28		—		255
Total personal	44,298		215,992		192,773		73,311		97,832		156,286		524,775		1,370		1,306,637
Total loans to individuals	169,128		758,522		344,934		213,396		247,949		916,693		847,711		25,833		3,524,166
Total loans	$	1,281,763	$	4,485,179	$	3,046,366	$	2,353,485	$	1,645,058	$	4,060,444	$	5,632,687	$	28,865	$	22,533,847

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 March 31, 2021 follows (in thousands): 

	As of March 31, 2021
	Total		With No Allowance		With Allowance		Related Allowance
Commercial:
Energy	$	101,800	$	48,042	$	53,758	$	13,893
Healthcare	3,187		3,187		—		—
Services	28,033		24,046		3,987		2,650
General business	14,053		13,935		118		118
Total commercial	147,073		89,210		57,863		16,661
Commercial real estate	27,243		13,642		13,601		3,390
Loans to individuals:
Residential mortgage	32,884		32,884		—		—
Residential mortgage guaranteed by U.S. government agencies	8,564		8,564		—		—
Personal	255		255		—		—
Total loans to individuals	41,703		41,703		—		—
Total	$	216,019	$	144,555	$	71,464	$	20,051

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 March 31, 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	$	3,183,861	$	—	$	—	$	18,627	$	3,202,488	$	—
Healthcare	3,287,571		—		—		3,187		3,290,758		—
Services	3,404,154		1,791		208		15,795		3,421,948		—
General business	2,722,467		7,712		1,843		10,568		2,742,590		145
Total commercial	12,598,053		9,503		2,051		48,177		12,657,784		145
Commercial real estate	4,482,750		134		—		20,463		4,503,347		—
Paycheck protection program	1,848,550		—		—		—		1,848,550		—
Loans to individuals:
Residential mortgage	1,782,825		7,215		415		7,023		1,797,478		250
Residential mortgage guaranteed by U.S. government agencies	274,265		50,175		13,059		82,552		420,051		77,009
Personal	1,306,435		90		40		72		1,306,637		—
Total loans to individuals	3,363,525		57,480		13,514		89,647		3,524,166		77,259
Total	$	22,292,878	$	67,117	$	15,565	$	158,287	$	22,533,847	$	77,404

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