Loans (Tables)

6 Months Ended

Jun. 30, 2020

Receivables [Abstract]

Loans

Loans were as follows:

	June 30, 2020		Percentage of Total		December 31, 2019		Percentage of Total
Commercial and industrial	$	5,004,229	27.9	%	$	5,187,466	35.2	%
Energy:
Production	1,162,673		6.5		1,348,900		9.2
Service	164,597		0.9		192,996		1.3
Other	97,610		0.5		110,986		0.8
Total energy	1,424,880		7.9		1,652,882		11.2
Paycheck Protection Program	3,162,279		17.6		—		—
Commercial real estate:
Commercial mortgages	5,042,546		28.1		4,594,113		31.1
Construction	1,265,550		7.0		1,312,659		8.9
Land	316,839		1.8		289,467		2.0
Total commercial real estate	6,624,935		36.9		6,196,239		42.0
Consumer real estate:
Home equity loans	346,210		1.9		375,596		2.6
Home equity lines of credit	395,099		2.2		354,671		2.4
Other	508,876		2.8		464,146		3.1
Total consumer real estate	1,250,185		6.9		1,194,413		8.1
Total real estate	7,875,120		43.8		7,390,652		50.1
Consumer and other	505,429		2.8		519,332		3.5
Total loans	$	17,971,937	100.0	%	$	14,750,332	100.0	%

Non-Accrual Loans, Segregated by Class of Loans

Non-accrual loans, segregated by class of loans, were as follows:

	June 30, 2020				December 31, 2019
	Total Non-Accrual		Non-Accrual with No Credit Loss Allowance		Total Non-Accrual		Non-Accrual with No Credit Loss Allowance
Commercial and industrial	$	27,146	$	10,623	$	26,038	$	13,266
Energy	36,239		30,892		65,761		3,281
Paycheck Protection Program	—		—		—		—
Commercial real estate:
Buildings, land and other	12,154		6,513		8,912		6,558
Construction	1,869		677		665		665
Consumer real estate	2,035		2,035		922		922
Consumer and other	18		—		5		—
Total	$	79,461	$	50,740	$	102,303	$	24,692

Financing Receivable, Non-Accrual Loans, Segregated by Class of Loan and Year of Origination

The following table presents non-accrual loans as of June 30, 2020 by class and year of origination.

	2020		2019		2018		2017		2016		Prior		Revolving Loans		Revolving Loans Converted to Term		Total
Commercial and industrial	$	1,439	$	2,951	$	8,023	$	2,130	$	290	$	111	$	8,163	$	4,039	$	27,146
Energy	27,628		—		—		—		—		—		2,929		5,682		36,239
Paycheck Protection Program	—		—		—		—		—		—		—		—		—
Commercial real estate:
Buildings, land and other	249		5,763		33		1,393		659		3,700		357		—		12,154
Construction	1,192		677		—		—		—		—		—		—		1,869
Consumer real estate	—		—		418		211		350		663		336		57		2,035
Consumer and other	—		—		—		—		—		—		18		—		18
Total	$	30,508	$	9,391	$	8,474	$	3,734	$	1,299	$	4,474	$	11,803	$	9,778	$	79,461

Age Analysis of Past Due Loans, Segregated by Class of Loans

An age analysis of past due loans (including both accruing and non-accruing loans), segregated by class of loans, as of June 30, 2020 was as follows:

	Loans 30-89 Days Past Due		Loans 90 or More Days Past Due		Total Past Due Loans		Current Loans		Total Loans		Accruing Loans 90 or More Days Past Due
Commercial and industrial	$	34,018	$	23,765	$	57,783	$	4,946,446	$	5,004,229	$	7,669
Energy	9,319		7,978		17,297		1,407,583		1,424,880		2,466
Paycheck Protection Program	—		—		—		3,162,279		3,162,279		—
Commercial real estate:
Buildings, land and other	10,271		9,593		19,864		5,339,521		5,359,385		5,225
Construction	3,164		—		3,164		1,262,386		1,265,550		—
Consumer real estate	10,437		5,876		16,313		1,233,872		1,250,185		4,661
Consumer and other	7,621		976		8,597		496,832		505,429		976
Total	$	74,830	$	48,188	$	123,018	$	17,848,919	$	17,971,937	$	20,997

Troubled Debt Restructurings

Troubled debt restructurings during the six months ended June 30, 2020 and June 30, 2019 are set forth in the following table.

	Six Months Ended June 30, 2020				Six Months Ended June 30, 2019
	Balance at Restructure		Balance at Period-End		Balance at Restructure		Balance at Period-End
Commercial and industrial	$	3,660	$	3,652	$	677	$	555
Commercial real estate:
Buildings, land and other	6,606		6,606		7,347		7,308
Construction	1,192		1,192		—		—
Consumer and other	1,104		1,104		—		—
	$	12,562	$	12,554	$	8,024	$	7,863

Restructured Loans Past Due in Excess of 90 Days on Financing Receivables

Additional information related to restructured loans as of or for the three months ended June 30, 2020 and June 30, 2019 is set forth in the following table.

	June 30, 2020		June 30, 2019
Restructured loans past due in excess of 90 days at period-end:
Number of loans	—		—
Dollar amount of loans	$	—	$	—
Restructured loans on non-accrual status at period end	7,631		3,890
Charge-offs of restructured loans:
Recognized in connection with restructuring	—		—
Recognized on previously restructured loans	—		—

Weighted Average Risk Grades for All Commercial Loans by Class and Year of Origination

The following tables present weighted-average risk grades for all commercial loans, by class and year of origination/renewal as of June 30, 2020. Paycheck Protection Program (“PPP”) loans are excluded as such loans are fully guaranteed by the Small Business Administration (“SBA”).

	2020		2019		2018		2017		2016		Prior		Revolving Loans		Revolving Loans Converted to Term		Total		W/A Risk Grade
Commercial and industrial
Risk grades 1-8	$	964,725	$	717,740	$	381,096	$	293,462	$	135,834	$	131,562	$	1,870,668	$	43,753	$	4,538,840	6.12
Risk grade 9	40,097		40,498		47,038		23,292		17,302		10,094		100,309		7,624		286,254		9.00
Risk grade 10	511		6,542		13,823		6,106		1,106		914		55,019		322		84,343		10.00
Risk grade 11	627		11,037		8,118		3,825		978		2,258		32,625		8,178		67,646		11.00
Risk grade 12	—		400		6,891		1,366		290		111		3,921		2,416		15,395		12.00
Risk grade 13	1,439		2,551		1,132		764		—		—		4,242		1,623		11,751		13.00
	$	1,007,399	$	778,768	$	458,098	$	328,815	$	155,510	$	144,939	$	2,066,784	$	63,916	$	5,004,229	6.45
W/A Risk grade	5.86		6.75		7.25		6.26		6.51		6.08		6.46		7.90		6.45
Energy
Risk grades 1-8	$	464,306	$	34,818	$	15,531	$	7,152	$	2,177	$	4,931	$	458,761	$	18,745	$	1,006,421	6.17
Risk grade 9	109,731		14,431		3,754		18		—		—		97,175		16,594		241,703		9.00
Risk grade 10	32,588		228		1,203		1,032		930		—		10,054		952		46,987		10.00
Risk grade 11	59,119		341		1,268		3,261		—		1,110		28,152		279		93,530		11.00
Risk grade 12	27,628		—		—		—		—		—		2,929		3,432		33,989		12.00
Risk grade 13	—		—		—		—		—		—		—		2,250		2,250		13.00
	$	693,372	$	49,818	$	21,756	$	11,463	$	3,107	$	6,041	$	597,071	$	42,252	$	1,424,880	7.24
W/A Risk grade	7.42		7.76		7.73		8.56		7.50		7.67		6.82		8.90		7.24

	2020		2019		2018		2017		2016		Prior		Revolving Loans		Revolving Loans Converted to Term		Total		W/A Risk Grade
Commercial real estate:
Buildings, land, other
Risk grades 1-8	$	738,500	$	1,050,204	$	781,460	$	749,286	$	471,551	$	812,382	$	68,195	$	54,199	$	4,725,777	6.97
Risk grade 9	2,459		75,727		41,972		67,920		77,455		103,423		2,150		783		371,889		9.00
Risk grade 10	995		20,053		3,206		35,727		29,801		56,419		2,422		2,876		151,499		10.00
Risk grade 11	3,353		11,407		3,798		38,848		14,901		20,944		3,100		1,715		98,066		11.00
Risk grade 12	249		4,963		33		1,393		659		3,450		294		—		11,041		12.00
Risk grade 13	—		800		—		—		—		250		63		—		1,113		13.00
	$	745,556	$	1,163,154	$	830,469	$	893,174	$	594,367	$	996,868	$	76,224	$	59,573	$	5,359,385	7.28
W/A Risk grade	7.20		7.27		7.13		7.44		7.62		7.17		7.29		6.93		7.28
Construction
Risk grades 1-8	$	189,575	$	435,960	$	362,978	$	764	$	1,178	$	16,956	$	131,793	$	—	$	1,139,204	7.15
Risk grade 9	3,103		11,714		49,915		7,818		6,984		—		14,514		—		94,048		9.00
Risk grade 10	13,124		12,864		2,589		891		—		—		—		—		29,468		10.00
Risk grade 11	—		—		—		—		—		961		—		—		961		11.00
Risk grade 12	992		677		—		—		—		—		—		—		1,669		12.00
Risk grade 13	200		—		—		—		—		—		—		—		200		13.00
	$	206,994	$	461,215	$	415,482	$	9,473	$	8,162	$	17,917	$	146,307	$	—	$	1,265,550	7.36
W/A Risk grade	7.30		7.23		7.64		9.00		8.75		6.31		6.97		—		7.36
Total commercial real estate	$	952,550	$	1,624,369	$	1,245,951	$	902,647	$	602,529	$	1,014,785	$	222,531	$	59,573	$	6,624,935	7.30
W/A Risk grade	7.22		7.26		7.30		7.45		7.63		7.16		7.08		6.93		7.30

Weighted Average Risk Grades for All Commercial Loans by Class

The following tables present weighted average risk grades for all commercial loans by class as of December 31, 2019.

	Commercial and Industrial			Energy			Commercial Real Estate - Buildings, Land and Other			Commercial Real Estate - Construction			Total Commercial Real Estate
	W/A Risk Grade	Loans		W/A Risk Grade	Loans		W/A Risk Grade	Loans		W/A Risk Grade	Loans		W/A Risk Grade	Loans
Risk grades 1-8	6.17	$	4,788,857	5.90	$	1,488,301	6.78	$	4,523,271	7.25	$	1,274,098	6.88	$	5,797,369
Risk grade 9	9.00	247,212		9.00	32,163		9.00	163,714		9.00	21,509		9.00	185,223
Risk grade 10	10.00	71,472		10.00	51,898		10.00	103,626		10.00	15,243		10.00	118,869
Risk grade 11	11.00	53,887		11.00	14,760		11.00	84,057		11.00	1,144		11.00	85,201
Risk grade 12	12.00	18,189		12.00	45,514		12.00	8,529		12.00	665		12.00	9,194
Risk grade 13	13.00	7,849		13.00	20,246		13.00	383		13.00	—		13.00	383
Total	6.44	$	5,187,466	6.39	$	1,652,882	7.01	$	4,883,580	7.31	$	1,312,659	7.07	$	6,196,239

Age analysis of Past Due Consumer Loans by Class and Year of Origination

Information about the payment status of consumer loans, segregated by portfolio segment and year of origination, as of June 30, 2020 was as follows:

	2020		2019		2018		2017		2016		Prior		Revolving Loans		Revolving Loans Converted to Term		Total
Consumer real estate:
Past due 30-89 days	$	308	$	392	$	744	$	1,424	$	951	$	5,552	$	594	$	472	$	10,437
Past due 90 or more days	631		139		825		364		385		1,622		1,772		138		5,876
Total past due	939		531		1,569		1,788		1,336		7,174		2,366		610		16,313
Current loans	153,945		208,060		125,413		107,404		84,106		162,656		373,461		18,827		1,233,872
Total	$	154,884	$	208,591	$	126,982	$	109,192	$	85,442	$	169,830	$	375,827	$	19,437	$	1,250,185
Consumer and other:
Past due 30-89 days	$	995	$	164	$	88	$	10	$	35	$	1	$	6,157	$	171	$	7,621
Past due 90 or more days	83		43		3		—		—		—		791		56		976
Total past due	1,078		207		91		10		35		1		6,948		227		8,597
Current loans	28,816		39,651		11,925		3,775		2,421		1,292		382,499		26,453		496,832
Total	$	29,894	$	39,858	$	12,016	$	3,785	$	2,456	$	1,293	$	389,447	$	26,680	$	505,429

Revolving Loans Converted to Term [Table Text Block]

Revolving loans that converted to term during the three and six months ended June 30, 2020 were as follows:

	Three Months Ended June 30, 2020		Six Months Ended June 30, 2020
Commercial and industrial	$	9,405	$	18,975
Energy	26,839		42,186
Commercial real estate:
Buildings, land and other	—		7,551
Construction	—		—
Consumer real estate	905		1,955
Consumer and other	10,371		10,371
Total	$	47,520	$	81,038

Financing Receivable, Allowance for Credit Loss By Loan Class Calculated in Accordance With CECL Methodology

The following table presents details of the allowance for credit losses on loans segregated by loan portfolio segment as of June 30, 2020, calculated in accordance with the CECL methodology described above. No allowance for credit losses has been recognized for PPP loans as such loans are fully guaranteed by the SBA.

	Commercial and Industrial		Energy		Commercial Real Estate		Consumer Real Estate		Consumer and Other		Total
Modeled expected credit losses	$	86,016	$	17,977	$	121,978	$	8,865	$	8,224	$	243,060
Q-Factor and other qualitative adjustments	430		20,590		(29,867)		133		43		(8,671)
Specific allocations	12,090		2,250		1,314		—		18		15,672
Total	$	98,536	$	40,817	$	93,425	$	8,998	$	8,285	$	250,061

Allowance for Credit Losses By Loan Class in Accordance With Methodology Used Prior to CECL

The following table presents details of the allowance for credit losses on loans segregated by loan portfolio segment as of December 31, 2019, calculated in accordance with our prior incurred loss methodology described in our 2019 Form 10-K.

	Commercial and Industrial		Energy		Commercial Real Estate		Consumer Real Estate		Consumer and Other		Total
Historical valuation allowances	$	29,015	$	7,873	$	21,947	$	2,690	$	7,562	$	69,087
Specific valuation allowances	7,849		20,246		383		—		5		28,483
General valuation allowances	9,840		5,196		4,201		904		(409)		19,732
Macroeconomic valuation allowances	4,889		4,067		4,506		519		884		14,865
Total	$	51,593	$	37,382	$	31,037	$	4,113	$	8,042	$	132,167

Activity in Allowance for Loan Losses by Portfolio Segment

The following table details activity in the allowance for credit losses on loans by portfolio segment for the three and six months ended June 30, 2020 and 2019. Allocation of a portion of the allowance to one category of loans does not preclude its availability to absorb losses in other categories. No allowance for credit losses has been recognized for PPP loans as such loans are fully guaranteed by the SBA.

	Commercial and Industrial		Energy		Commercial Real Estate		Consumer Real Estate		Consumer and Other		Total
Three months ended:
June 30, 2020
Beginning balance	$	92,152	$	103,201	$	52,319	$	8,170	$	8,039	$	263,881
Credit loss expense	7,334		(27,342)		44,587		352		2,297		27,228
Charge-offs	(1,841)		(35,042)		(3,511)		(135)		(4,178)		(44,707)
Recoveries	891		—		30		611		2,127		3,659
Net charge-offs	(950)		(35,042)		(3,481)		476		(2,051)		(41,048)
Ending balance	$	98,536	$	40,817	$	93,425	$	8,998	$	8,285	$	250,061
June 30, 2019
Beginning balance	$	58,571	$	25,343	$	36,455	$	5,661	$	10,320	$	136,350
Credit loss expense	1,597		2,446		(13)		262		2,108		6,400
Charge-offs	(3,389)		(2,000)		(557)		(601)		(5,103)		(11,650)
Recoveries	935		29		29		315		2,521		3,829
Net charge-offs	(2,454)		(1,971)		(528)		(286)		(2,582)		(7,821)
Ending balance	$	57,714	$	25,818	$	35,914	$	5,637	$	9,846	$	134,929
Six months ended:
June 30, 2020
Beginning balance	$	51,593	$	37,382	$	31,037	$	4,113	$	8,042	$	132,167
Impact of adopting ASC 326	21,263		(10,453)		(13,519)		2,392		(2,248)		(2,565)
Credit loss expense	29,284		82,664		79,348		1,922		6,935		200,153
Charge-offs	(6,210)		(68,842)		(3,584)		(420)		(9,183)		(88,239)
Recoveries	2,606		66		143		991		4,739		8,545
Net charge-offs	(3,604)		(68,776)		(3,441)		571		(4,444)		(79,694)
Ending balance	$	98,536	$	40,817	$	93,425	$	8,998	$	8,285	$	250,061
June 30, 2019
Beginning balance	$	48,580	$	29,052	$	38,777	$	6,103	$	9,620	$	132,132
Credit loss expense	13,526		(1,310)		(2,365)		1,509		6,043		17,403
Charge-offs	(6,077)		(2,000)		(617)		(2,379)		(10,800)		(21,873)
Recoveries	1,685		76		119		404		4,983		7,267
Net charge-offs	(4,392)		(1,924)		(498)		(1,975)		(5,817)		(14,606)
Ending balance	$	57,714	$	25,818	$	35,914	$	5,637	$	9,846	$	134,929

Investment in Loans Related to Allowance for Loan Losses by Portfolio Segment Disaggregated Based on Impairment Methodology

The following table presents loans that were evaluated for expected credit losses on an individual basis and the related specific allocations, by loan portfolio segment as of June 30, 2020 and December 31, 2019.

	June 30, 2020				December 31, 2019
	Loan Balance		Specific Allocations		Loan Balance		Specific Allocations
Commercial and industrial	$	46,087	$	12,090	$	24,360	$	7,849
Energy	35,904		2,250		65,244		20,246
Paycheck Protection Program	—		—		—		—
Commercial real estate:
Buildings, land and other	28,582		1,114		8,609		383
Construction	1,869		200		665		—
Consumer real estate	1,334		—		570		—
Consumer and other	18		18		5		5
Total	$	113,794	$	15,672	$	99,453	$	28,483