Loans and allowance for credit losses | LOANS HELD FOR INVESTMENT AND ALLOWANCE FOR LOAN LOSSES At June 30, 2017 and December 31, 2016 , loans held for investment were as follows (in thousands): June 30, December 31, Commercial $ 8,250,952 $ 7,291,545 Mortgage finance 5,183,600 4,497,338 Construction 2,242,562 2,098,706 Real estate 3,569,787 3,462,203 Consumer 39,122 34,587 Leases 274,863 185,529 Gross loans held for investment 19,560,886 17,569,908 Deferred income (net of direct origination costs) (96,933 ) (71,559 ) Allowance for loan losses (174,225 ) (168,126 ) Total loans held for investment $ 19,289,728 $ 17,330,223 Commercial Loans and Leases. Our commercial loan portfolio is comprised of lines of credit for working capital and term loans and leases to finance equipment and other business assets. Our energy production loans are generally collateralized with proven reserves based on appropriate valuation standards and take into account the risk of oil and gas price volatility. Our commercial loans and leases are underwritten after carefully evaluating and understanding the borrower’s ability to operate profitably. Our underwriting standards are designed to promote relationship banking rather than to make loans on a transaction basis. Our lines of credit typically are limited to a percentage of the value of the assets securing the line. Lines of credit and term loans typically are reviewed annually, or more frequently, as needed, and are supported by accounts receivable, inventory, equipment and other assets of our clients’ businesses. Mortgage Finance Loans. Our mortgage finance loans consist of ownership interests purchased in single-family residential mortgages funded through our mortgage finance group. These loans are typically held on our balance sheet for 10 to 20 days. We have agreements with mortgage lenders and purchase interests in individual loans they originate. All loans are underwritten consistent with established programs for permanent financing with financially sound investors. Substantially all loans are conforming loans. Balances as of June 30, 2017 and December 31, 2016 are stated net of $234.1 million and $839.0 million participations sold, respectively. Construction Loans. Our construction loan portfolio consists primarily of single- and multi-family residential properties and commercial projects used in manufacturing, warehousing, service or retail businesses. Our construction loans generally have terms of one to three years. We typically make construction loans to developers, builders and contractors that have an established record of successful project completion and loan repayment and have a substantial equity investment in the borrowers. Loan amounts are derived primarily from the Bank's evaluation of expected cash flows available to service debt from stabilized projects under hypothetically stressed conditions. Construction loans are also based in part upon estimates of costs and value associated with the completed project. Sources of repayment for these types of loans may be pre-committed permanent loans from other lenders, sales of developed property, or an interim loan commitment from us until permanent financing is obtained. The nature of these loans makes ultimate repayment sensitive to overall economic conditions. Borrowers may not be able to correct conditions of default in loans, increasing risk of exposure to classification, non-performing status, reserve allocation and actual credit loss and foreclosure. These loans typically have floating rates and commitment fees. Real Estate Loans. A portion of our real estate loan portfolio is comprised of loans secured by properties other than market risk or investment-type real estate. Market risk loans are real estate loans where the primary source of repayment is expected to come from the sale, permanent financing or lease of the real property collateral. We generally provide temporary financing for commercial and residential property. These loans are viewed primarily as cash flow loans and secondarily as loans secured by real estate. Our real estate loans generally have maximum terms of five to seven years, and we provide loans with both floating and fixed rates. We generally avoid long-term loans for commercial real estate held for investment. Real estate loans may be more adversely affected by conditions in the real estate markets or in the general economy. Appraised values may be highly variable due to market conditions and the impact of the inability of potential purchasers and lessees to obtain financing and a lack of transactions at comparable values. At June 30, 2017 and December 31, 2016 , we had a blanket floating lien on certain real estate-secured loans, mortgage finance loans and certain securities used as collateral for Federal Home Loan Bank (“FHLB”) borrowings. Summary of Loan Loss Experience The allowance for loan losses is comprised of general reserves, specific reserves for impaired loans and an additional qualitative reserve based on our estimate of losses inherent in the portfolio at the balance sheet date, but not yet identified with specified loans. We consider the allowance at June 30, 2017 to be appropriate, given management's assessment of losses inherent in the portfolio as of the evaluation date, the significant growth in the loan and lease portfolio, current economic conditions in our market areas and other factors. The following tables summarize the credit risk profile of our loan portfolio by internally assigned grades and non-accrual status as of June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 Commercial Mortgage Finance Construction Real Estate Consumer Leases Total Grade: Pass $ 7,984,302 $ 5,183,600 $ 2,236,870 $ 3,523,118 $ 38,637 $ 254,772 $ 19,221,299 Special mention 43,223 — 5,692 26,290 369 2,666 78,240 Substandard-accruing 103,859 — — 16,217 116 17,425 137,617 Non-accrual 119,568 — — 4,162 — — 123,730 Total loans held for investment $ 8,250,952 $ 5,183,600 $ 2,242,562 $ 3,569,787 $ 39,122 $ 274,863 $ 19,560,886 December 31, 2016 Commercial Mortgage Finance Construction Real Estate Consumer Leases Total Grade: Pass $ 6,941,310 $ 4,497,338 $ 2,074,859 $ 3,430,346 $ 34,249 $ 181,914 $ 17,160,016 Special mention 69,447 — 10,901 21,932 — 3,532 105,812 Substandard-accruing 115,848 — 12,787 7,516 138 — 136,289 Non-accrual 164,940 — 159 2,409 200 83 167,791 Total loans held for investment $ 7,291,545 $ 4,497,338 $ 2,098,706 $ 3,462,203 $ 34,587 $ 185,529 $ 17,569,908 The following table details activity in the allowance for loan losses by portfolio segment for the six months ended June 30, 2017 and 2016 . Allocation of a portion of the allowance to one category of loans does not preclude its availability to absorb losses in other categories. June 30, 2017 (in thousands) Commercial Mortgage Finance Construction Real Estate Consumer Leases Additional Qualitative Reserve Total Beginning balance $ 128,768 $ — $ 13,144 $ 19,149 $ 241 $ 1,124 $ 5,700 $ 168,126 Provision for loan losses 19,384 — 680 3,436 287 2,989 (2,559 ) 24,217 Charge-offs 21,543 — — 40 180 — — 21,763 Recoveries 3,442 — 101 53 41 8 — 3,645 Net charge-offs (recoveries) 18,101 — (101 ) (13 ) 139 (8 ) — 18,118 Ending balance $ 130,051 $ — $ 13,925 $ 22,598 $ 389 $ 4,121 $ 3,141 $ 174,225 Period end amount allocated to: Loans individually evaluated for impairment $ 28,382 $ — $ — $ 180 $ — $ — $ — $ 28,562 Loans collectively evaluated for impairment 101,669 — 13,925 22,418 389 4,121 3,141 145,663 Ending balance $ 130,051 $ — $ 13,925 $ 22,598 $ 389 $ 4,121 $ 3,141 $ 174,225 June 30, 2016 (in thousands) Commercial Mortgage Finance Construction Real Estate Consumer Leases Additional Qualitative Reserve Total Beginning balance $ 112,446 $ — $ 6,836 $ 13,381 $ 338 $ 3,931 $ 4,179 $ 141,111 Provision for loan losses 44,324 — 758 1,423 (28 ) (2,531 ) 1,710 45,656 Charge-offs 24,287 — — 528 — — — 24,815 Recoveries 5,334 — 34 21 11 45 — 5,445 Net charge-offs (recoveries) 18,953 — (34 ) 507 (11 ) (45 ) — 19,370 Ending balance $ 137,817 $ — $ 7,628 $ 14,297 $ 321 $ 1,445 $ 5,889 $ 167,397 Period end amount allocated to: Loans individually evaluated for impairment $ 30,775 $ — $ — $ 196 $ — $ — $ — $ 30,971 Loans collectively evaluated for impairment 107,042 — 7,628 14,101 321 1,445 5,889 136,426 Ending balance $ 137,817 $ — $ 7,628 $ 14,297 $ 321 $ 1,445 $ 5,889 $ 167,397 The table below presents the activity in the portion of the allowance for credit losses related to losses on unfunded commitments for the three and six months ended June 30, 2017 and 2016 (in thousands). This liability is recorded in other liabilities in the consolidated balance sheet. Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Beginning balance $ 10,847 $ 10,216 $ 11,422 $ 9,011 Provision for off-balance sheet credit losses (1,642 ) (861 ) (2,217 ) 344 Ending balance $ 9,205 $ 9,355 $ 9,205 $ 9,355 We have traditionally maintained an additional qualitative reserve component to compensate for the uncertainty and complexity in estimating loan and lease losses including factors and conditions that may not be fully reflected in the determination and application of the allowance allocation percentages. We believe the level of additional qualitative reserve at June 30, 2017 is warranted due to the continued uncertain economic environment which has produced losses, including those resulting from borrowers' misstatement of financial information or inaccurate certification of collateral values. Such losses are not necessarily correlated with historical loss trends or general economic conditions. Our methodology used to calculate the allowance considers historical losses; however, the historical loss rates for specific product types or credit risk grades may not fully incorporate the effects of continued weakness in the economy. Our recorded investment in loans as of June 30, 2017 , December 31, 2016 and June 30, 2016 related to each balance in the allowance for loan losses by portfolio segment and disaggregated on the basis of our impairment methodology was as follows (in thousands): June 30, 2017 Commercial Mortgage Finance Construction Real Estate Consumer Leases Total Loans individually evaluated for impairment $ 120,770 $ — $ — $ 4,514 $ — $ — $ 125,284 Loans collectively evaluated for impairment 8,130,182 5,183,600 2,242,562 3,565,273 39,122 274,863 19,435,602 Total $ 8,250,952 $ 5,183,600 $ 2,242,562 $ 3,569,787 $ 39,122 $ 274,863 $ 19,560,886 December 31, 2016 Commercial Mortgage Finance Construction Real Estate Consumer Leases Total Loans individually evaluated for impairment $ 166,669 $ — $ 159 $ 3,751 $ 200 $ 83 $ 170,862 Loans collectively evaluated for impairment 7,124,876 4,497,338 2,098,547 3,458,452 34,387 185,446 17,399,046 Total $ 7,291,545 $ 4,497,338 $ 2,098,706 $ 3,462,203 $ 34,587 $ 185,529 $ 17,569,908 June 30, 2016 Commercial Mortgage Finance Construction Real Estate Consumer Leases Total Loans individually evaluated for impairment $ 164,339 $ — $ — $ 4,210 $ — $ — $ 168,549 Loans collectively evaluated for impairment 7,014,025 5,260,027 2,023,725 3,224,643 26,283 103,565 17,652,268 Total $ 7,178,364 $ 5,260,027 $ 2,023,725 $ 3,228,853 $ 26,283 $ 103,565 $ 17,820,817 Generally we place loans on non-accrual when there is a clear indication that the borrower’s cash flow may not be sufficient to meet payments as they become due, which is generally when a loan is 90 days past due. When a loan is placed on non-accrual status, all previously accrued and unpaid interest is reversed. Interest income is subsequently recognized on a cash basis as long as the remaining unpaid principal amount of the loan is deemed to be fully collectible. If collectability is questionable, then cash payments are applied to principal. As of June 30, 2017 , none of our non-accrual loans were earning on a cash basis compared to $ 811,000 at December 31, 2016 . A loan is placed back on accrual status when both principal and interest are current and it is probable that we will be able to collect all amounts due (both principal and interest) according to the terms of the loan agreement. A loan held for investment is considered impaired when, based on current information and events, it is probable that we will be unable to collect all amounts due (both principal and interest) according to the terms of the original loan agreement. In accordance with ASC 310 Receivables , we have also included all restructured and formerly restructured loans in our impaired loan totals. The following tables detail our impaired loans, by portfolio class, as of June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized With no related allowance recorded: Commercial Business loans $ 21,624 $ 23,873 $ — $ 24,135 $ — Energy 36,577 47,821 — 41,206 — Construction Market risk — — — — — Real estate Market risk — — — — — Commercial 2,591 2,591 — 2,435 — Secured by 1-4 family — — — — — Consumer — — — — — Leases — — — — — Total impaired loans with no allowance recorded $ 60,792 $ 74,285 $ — $ 67,776 $ — With an allowance recorded: Commercial Business loans $ 16,510 $ 17,330 $ 2,908 $ 21,320 $ — Energy 46,059 59,761 25,474 58,030 6 Construction Market risk — — — 53 — Real estate Market risk 352 352 8 1,009 — Commercial — — — — — Secured by 1-4 family 1,571 1,571 172 1,153 — Consumer — — — 133 — Leases — — — 55 — Total impaired loans with an allowance recorded $ 64,492 $ 79,014 $ 28,562 $ 81,753 $ 6 Combined: Commercial Business loans $ 38,134 $ 41,203 $ 2,908 $ 45,455 $ — Energy 82,636 107,582 25,474 99,236 6 Construction Market risk — — — 53 — Real estate Market risk 352 352 8 1,009 — Commercial 2,591 2,591 — 2,435 — Secured by 1-4 family 1,571 1,571 172 1,153 — Consumer — — — 133 — Leases — — — 55 — Total impaired loans $ 125,284 $ 153,299 $ 28,562 $ 149,529 $ 6 December 31, 2016 Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized With no related allowance recorded: Commercial Business loans $ 23,868 $ 27,992 $ — $ 12,361 $ — Energy 46,753 54,522 — 54,075 — Construction Market risk — — — 2,778 — Real estate Market risk — — — — — Commercial 2,083 2,083 — 4,483 38 Secured by 1-4 family — — — — — Consumer — — — — — Leases — — — 403 — Total impaired loans with no allowance recorded $ 72,704 $ 84,597 $ — $ 74,100 $ 38 With an allowance recorded: Commercial Business loans $ 21,303 $ 21,303 $ 7,055 $ 22,277 $ — Energy 74,745 88,987 27,350 73,637 24 Construction Market risk 159 159 24 53 — Real estate Market risk 1,342 1,342 20 3,000 — Commercial — — — — — Secured by 1-4 family 326 326 113 435 — Consumer 200 200 30 67 — Leases 83 83 13 548 — Total impaired loans with an allowance recorded $ 98,158 $ 112,400 $ 34,605 $ 100,017 $ 24 Combined: Commercial Business loans $ 45,171 $ 49,295 $ 7,055 $ 34,638 $ — Energy 121,498 143,509 27,350 127,712 24 Construction Market risk 159 159 24 2,831 — Real estate Market risk 1,342 1,342 20 3,000 — Commercial 2,083 2,083 — 4,483 38 Secured by 1-4 family 326 326 113 435 — Consumer 200 200 30 67 — Leases 83 83 13 951 — Total impaired loans $ 170,862 $ 196,997 $ 34,605 $ 174,117 $ 62 Average impaired loans outstanding during the six months ended June 30, 2017 and 2016 totaled $149.5 million and $ 177.5 million , respectively. The table below provides an age analysis of our loans held for investment as of June 30, 2017 (in thousands): 30-59 Days Past Due 60-89 Days Past Due Greater Than 90 Days and Accruing(1) Total Past Due Non-accrual Current Total Commercial Business loans $ 22,321 $ 6,988 $ 9,340 $ 38,649 $ 36,932 $ 7,205,942 $ 7,281,523 Energy 1,579 — — 1,579 82,636 885,214 969,429 Mortgage finance loans — — — — — 5,183,600 5,183,600 Construction Market risk — — — — — 2,216,582 2,216,582 Secured by 1-4 family — — — — — 25,980 25,980 Real estate Market risk 3,899 — 1,630 5,529 — 2,597,565 2,603,094 Commercial 536 10,778 — 11,314 2,591 713,946 727,851 Secured by 1-4 family 5,221 57 107 5,385 1,571 231,886 238,842 Consumer — — — — — 39,122 39,122 Leases 117 — — 117 — 274,746 274,863 Total loans held for investment $ 33,673 $ 17,823 $ 11,077 $ 62,573 $ 123,730 $ 19,374,583 $ 19,560,886 (1) Loans past due 90 days and still accruing includes premium finance loans of $6.3 million . These loans are generally secured by obligations of insurance carriers to refund premiums on canceled insurance policies. The refund of premiums from the insurance carriers can take 180 days or longer from the cancellation date. Restructured loans are loans on which, due to the borrower’s financial difficulties, we have granted a concession that we would not otherwise consider for borrowers of similar credit quality. This may include a transfer of real estate or other assets from the borrower, a modification of loan terms, or a combination of the two. Modifications of terms that could potentially qualify as a restructuring include reduction of the contractual interest rate, extension of the maturity date at a contractual interest rate lower than the current rate for new debt with similar risk, a reduction of the face amount of debt or forgiveness of either principal or accrued interest. At June 30, 2017 and December 31, 2016 , we did not have any loans considered restructured that were not on non-accrual. Of the non-accrual loans at June 30, 2017 and December 31, 2016 , $16.7 million and $18.1 million , respectively, met the criteria for restructured. These loans had no unfunded commitments at their respective balance sheet dates. A loan continues to qualify as restructured until a consistent payment history or change in borrower’s financial condition has been evidenced, generally over no less than twelve months. Assuming that the restructuring agreement specifies an interest rate at the time of the restructuring that is greater than or equal to the rate that we are willing to accept for a new extension of credit with comparable risk, then the loan no longer has to be considered a restructuring if it is in compliance with the modified terms in calendar years after the year of the restructure. The following table summarizes, for the six months ended June 30, 2017 and 2016 , loans that were restructured during 2017 and 2016 (in thousands): June 30, 2017 Number of Restructured Loans Balance at Restructure Balance at Period-End Energy loans 1 $ 1,070 $ 700 Commercial business loans 1 $ 599 $ 672 Total new restructured loans in 2017 2 $ 1,669 $ 1,372 June 30, 2016 Number of Restructured Loans Balance at Restructure Balance at Period-End Energy loans 2 $ 14,235 $ 14,054 Total new restructured loans in 2016 2 $ 14,235 $ 14,054 The restructured loans generally include terms to temporarily place loans on interest only, extend the payment terms or reduce the interest rate. We did not forgive any principal on the above loans. The restructuring of the loans did not have a significant impact on our allowance for loan losses at June 30, 2017 or 2016 . The following table provides information on how restructured loans were modified during the six months ended June 30, 2017 and 2016 (in thousands): Six months ended June 30, 2017 2016 Extended maturity $ 700 $ — Adjusted payment schedule — 12,735 Combination of maturity extension and payment schedule adjustment — 1,319 Other 672 — Total $ 1,372 $ 14,054 As of June 30, 2017 and 2016 , we did not have any loans that were restructured within the last 12 months that subsequently defaulted. |