Loans (Tables)

9 Months Ended

Sep. 30, 2018

Loans were as follows:



	September 30, 2018		Percentage of Total		December 31, 2017		Percentage of Total
Commercial and industrial	$	5,029,754	36.4	%	$	4,792,388	36.4	%
Energy:
Production	1,220,771		8.8		1,182,326		9.0
Service	164,889		1.2		171,795		1.3
Other	133,708		1.0		144,972		1.1
Total energy	1,519,368		11.0		1,499,093		11.4
Commercial real estate:
Commercial mortgages	4,078,787		29.5		3,887,742		29.6
Construction	1,208,870		8.7		1,066,696		8.1
Land	315,384		2.3		331,986		2.5
Total commercial real estate	5,603,041		40.5		5,286,424		40.2
Consumer real estate:
Home equity loans	352,292		2.5		355,342		2.7
Home equity lines of credit	326,876		2.4		291,950		2.2
Other	419,965		3.1		376,002		2.9
Total consumer real estate	1,099,133		8.0		1,023,294		7.8
Total real estate	6,702,174		48.5		6,309,718		48.0
Consumer and other	563,542		4.1		544,466		4.2
Total loans	$	13,814,838	100.0	%	$	13,145,665	100.0	%

Non-Accrual Loans, Segregated by Class of Loans

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



	September 30, 2018		December 31, 2017
Commercial and industrial	$	12,278	$	46,186
Energy	51,802		94,302
Commercial real estate:
Buildings, land and other	15,913		7,589
Construction	—		—
Consumer real estate	971		2,109
Consumer and other	1,637		128
Total	$	82,601	$	150,314

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 September 30, 2018 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	$	33,985	$	10,250	$	44,235	$	4,985,519	$	5,029,754	$	3,963
Energy	3,251		2,221		5,472		1,513,896		1,519,368		818
Commercial real estate:
Buildings, land and other	21,596		2,980		24,576		4,369,595		4,394,171		2,606
Construction	784		1,042		1,826		1,207,044		1,208,870		1,042
Consumer real estate	7,743		1,773		9,516		1,089,617		1,099,133		1,432
Consumer and other	6,098		1,766		7,864		555,678		563,542		1,724
Total	$	73,457	$	20,032	$	93,489	$	13,721,349	$	13,814,838	$	11,585

Impaired Loans

Impaired loans are set forth in the following table. No interest income was recognized on impaired loans subsequent to their classification as impaired.



	Unpaid Contractual Principal Balance		Recorded Investment With No Allowance		Recorded Investment With Allowance		Total Recorded Investment		Related Allowance
September 30, 2018
Commercial and industrial	$	19,857	$	3,153	$	6,574	$	9,727	$	4,622
Energy	68,087		7,942		43,614		51,556		12,672
Commercial real estate:
Buildings, land and other	15,961		2,309		12,876		15,185		2,599
Construction	—		—		—		—		—
Consumer real estate	293		293		—		293		—
Consumer and other	1,595		—		1,595		1,595		1,595
Total	$	105,793	$	13,697	$	64,659	$	78,356	$	21,488
December 31, 2017
Commercial and industrial	$	60,781	$	28,038	$	15,722	$	43,760	$	7,553
Energy	99,606		33,080		61,162		94,242		13,267
Commercial real estate:
Buildings, land and other	10,795		6,394		—		6,394		—
Construction	—		—		—		—		—
Consumer real estate	1,214		1,214		—		1,214		—
Consumer and other	—		—		—		—		—
Total	$	172,396	$	68,726	$	76,884	$	145,610	$	20,820

Average Recorded Investment In Impaired Loans

The average recorded investment in impaired loans was as follows:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Commercial and industrial	$	13,447	$	26,910	$	21,025	$	26,651
Energy	78,772		76,008		82,640		72,055
Commercial real estate:
Buildings, land and other	14,306		5,553		12,328		6,106
Construction	—		—		—		—
Consumer real estate	671		1,209		807		1,155
Consumer and other	1,073		—		805		13
Total	$	108,269	$	109,680	$	117,605	$	105,980

Troubled Debt Restructurings

Troubled debt restructurings during the nine months ended September 30, 2018 and September 30, 2017 are set forth in the following table.



	Nine Months Ended September 30, 2018				Nine Months Ended September 30, 2017
	Balance at Restructure		Balance at Period-End		Balance at Restructure		Balance at Period-End
Commercial and industrial	$	2,203	$	—	$	4,026	$	3,875
Energy	13,708		—		56,097		55,023
	$	15,911	$	—	$	60,123	$	58,898

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

Additional information related to restructured loans as of or for the nine months ended September 30, 2018 and September 30, 2017 is set forth in the following table.



	September 30, 2018		September 30, 2017
Restructured loans past due in excess of 90 days at period-end:
Number of loans	—		1
Dollar amount of loans	$	—	$	43,137
Restructured loans on non-accrual status at period end	—		54,082
Charge-offs of restructured loans:
Recognized in connection with restructuring	—		—
Recognized on previously restructured loans	4,650		9,951
Proceeds from sale of restructured loans	15,750		—

Weighted Average Risk Grades for All Commercial Loans by Class

The following tables present weighted-average risk grades for all commercial loans by class.



	September 30, 2018			December 31, 2017
	Weighted Average Risk Grade	Loans		Weighted Average Risk Grade	Loans
Commercial and industrial:
Risk grades 1-8	6.10	$	4,755,739	6.06	$	4,378,839
Risk grade 9	9.00	123,199		9.00	170,285
Risk grade 10	10.00	67,645		10.00	99,260
Risk grade 11	11.00	70,893		11.00	97,818
Risk grade 12	12.00	7,656		12.00	38,633
Risk grade 13	13.00	4,622		13.00	7,553
Total	6.31	$	5,029,754	6.41	$	4,792,388
Energy
Risk grades 1-8	5.81	$	1,367,235	6.01	$	1,199,207
Risk grade 9	9.00	13,352		9.00	50,427
Risk grade 10	10.00	42,862		10.00	64,282
Risk grade 11	11.00	44,116		11.00	90,875
Risk grade 12	12.00	39,131		12.00	81,035
Risk grade 13	13.00	12,672		13.00	13,267
Total	6.32	$	1,519,368	6.97	$	1,499,093
Commercial real estate:
Buildings, land and other
Risk grades 1-8	6.77	$	4,091,571	6.75	$	3,868,659
Risk grade 9	9.00	135,521		9.00	151,487
Risk grade 10	10.00	60,169		10.00	129,391
Risk grade 11	11.00	90,997		11.00	62,602
Risk grade 12	12.00	13,314		12.00	7,589
Risk grade 13	13.00	2,599		13.00	—
Total	6.99	$	4,394,171	7.00	$	4,219,728
Construction
Risk grades 1-8	7.10	$	1,129,492	7.11	$	1,019,635
Risk grade 9	9.00	51,058		9.00	18,042
Risk grade 10	10.00	26,035		10.00	23,393
Risk grade 11	11.00	2,285		11.00	5,626
Risk grade 12	12.00	—		12.00	—
Risk grade 13	13.00	—		13.00	—
Total	7.25	$	1,208,870	7.23	$	1,066,696

Net (Charge-Offs)/Recoveries, Segregated by Class of Loans

Net (charge-offs)/recoveries, segregated by class of loans, were as follows:



	Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017
Commercial and industrial	$	(7,807	)	$	(4,565	)	$	(19,030	)	$	(12,155	)
Energy	(5,347		)	451			(10,272		)	(10,010		)
Commercial real estate:
Buildings, land and other	33			266			(288		)	768
Construction	3			2			11			8
Consumer real estate	(388		)	(629		)	(1,078		)	(422		)
Consumer and other	(1,792		)	(1,760		)	(4,975		)	(4,289		)
Total	$	(15,298	)	$	(6,235	)	$	(35,632	)	$	(26,100	)

Unallocated Portion of Allowance for Loan Losses

The following table presents details of the allowance for loan losses allocated to each portfolio segment as of September 30, 2018 and December 31, 2017 and detailed on the basis of the impairment evaluation methodology we used:



	Commercial and Industrial		Energy		Commercial Real Estate		Consumer Real Estate		Consumer and Other			Total
September 30, 2018
Historical valuation allowances	$	25,582	$	9,654	$	20,441	$	2,641	$	6,815		$	65,133
Specific valuation allowances	4,622		12,672		2,599		—		1,595			21,488
General valuation allowances	9,361		5,849		4,187		1,620		(114		)	20,903
Macroeconomic valuation allowances	11,426		3,270		11,977		1,933		1,448			30,054
Total	$	50,991	$	31,445	$	39,204	$	6,194	$	9,744		$	137,578
Allocated to loans:
Individually evaluated	$	4,622	$	12,672	$	2,599	$	—	$	1,595		$	21,488
Collectively evaluated	46,369		18,773		36,605		6,194		8,149			116,090
Total	$	50,991	$	31,445	$	39,204	$	6,194	$	9,744		$	137,578
December 31, 2017
Historical valuation allowances	$	26,401	$	22,073	$	18,931	$	2,473	$	5,603		$	75,481
Specific valuation allowances	7,553		13,267		—		—		—			20,820
General valuation allowances	9,112		7,964		4,165		2,133		(91		)	23,283
Macroeconomic valuation allowances	16,548		8,224		7,852		1,051		2,105			35,780
Total	$	59,614	$	51,528	$	30,948	$	5,657	$	7,617		$	155,364
Allocated to loans:
Individually evaluated	$	7,553	$	13,267	$	—	$	—	$	—		$	20,820
Collectively evaluated	52,061		38,261		30,948		5,657		7,617			134,544
Total	$	59,614	$	51,528	$	30,948	$	5,657	$	7,617		$	155,364

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

Our recorded investment in loans as of September 30, 2018 and December 31, 2017 related to each balance in the allowance for loan losses by portfolio segment and detailed on the basis of the impairment methodology we used was as follows:



	Commercial and Industrial		Energy		Commercial Real Estate		Consumer Real Estate		Consumer and Other		Total
September 30, 2018
Individually evaluated	$	9,727	$	51,556	$	15,185	$	293	$	1,595	$	78,356
Collectively evaluated	5,020,027		1,467,812		5,587,856		1,098,840		561,947		13,736,482
Total	$	5,029,754	$	1,519,368	$	5,603,041	$	1,099,133	$	563,542	$	13,814,838
December 31, 2017
Individually evaluated	$	43,760	$	94,242	$	6,394	$	1,214	$	—	$	145,610
Collectively evaluated	4,748,628		1,404,851		5,280,030		1,022,080		544,466		13,000,055
Total	$	4,792,388	$	1,499,093	$	5,286,424	$	1,023,294	$	544,466	$	13,145,665

Activity in Allowance for Loan Losses by Portfolio Segment

The following table details activity in the allowance for loan losses by portfolio segment for the three and nine months ended September 30, 2018 and 2017. Allocation of a portion of the allowance to one category of loans does not preclude its availability to absorb losses in other categories.



	Commercial and Industrial			Energy			Commercial Real Estate			Consumer Real Estate			Consumer and Other			Total
Three months ended:
September 30, 2018
Beginning balance	$	57,713		$	37,313		$	38,918		$	6,336		$	9,946		$	150,226
Provision for loan losses	1,085			(521		)	250			246			1,590			2,650
Charge-offs	(8,491		)	(5,400		)	—			(431		)	(4,274		)	(18,596		)
Recoveries	684			53			36			43			2,482			3,298
Net charge-offs	(7,807		)	(5,347		)	36			(388		)	(1,792		)	(15,298		)
Ending balance	$	50,991		$	31,445		$	39,204		$	6,194		$	9,744		$	137,578
September 30, 2017
Beginning balance	$	48,906		$	54,277		$	33,002		$	5,535		$	7,838		$	149,558
Provision for loan losses	4,096			(2,815		)	4,805			1,969			2,925			10,980
Charge-offs	(5,468		)	—			—			(766		)	(4,120		)	(10,354		)
Recoveries	903			451			268			137			2,360			4,119
Net charge-offs	(4,565		)	451			268			(629		)	(1,760		)	(6,235		)
Ending balance	$	48,437		$	51,913		$	38,075		$	6,875		$	9,003		$	154,303

Nine months ended:
September 30, 2018
Beginning balance	$	59,614		$	51,528		$	30,948		$	5,657		$	7,617		$	155,364
Provision for loan losses	10,407			(9,811		)	8,533			1,615			7,102			17,846
Charge-offs	(21,896		)	(10,939		)	(619		)	(1,632		)	(12,240		)	(47,326		)
Recoveries	2,866			667			342			554			7,265			11,694
Net charge-offs	(19,030		)	(10,272		)	(277		)	(1,078		)	(4,975		)	(35,632		)
Ending balance	$	50,991		$	31,445		$	39,204		$	6,194		$	9,744		$	137,578
September 30, 2017
Beginning balance	$	52,915		$	60,653		$	30,213		$	4,238		$	5,026		$	153,045
Provision for loan losses	7,677			1,270			7,086			3,059			8,266			27,358
Charge-offs	(14,574		)	(10,595		)	(14		)	(779		)	(11,291		)	(37,253		)
Recoveries	2,419			585			790			357			7,002			11,153
Net charge-offs	(12,155		)	(10,010		)	776			(422		)	(4,289		)	(26,100		)
Ending balance	$	48,437		$	51,913		$	38,075		$	6,875		$	9,003		$	154,303