Texas Capital Bancshares (TCBI) 10-Q 18 Oct 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 17, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	TEXAS CAPITAL BANCSHARES INC/TX
Entity Central Index Key	1,077,428
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		50,181,585

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets
Cash and due from banks	$ 169,481	$ 178,010
Interest-bearing deposits in other banks	2,585,570	2,697,581
Federal funds sold and securities purchased under resale agreements	30,000	30,000
Investment securities	117,389	23,511
Loans held for sale ($1,651.9 million and $1,007.7 million at September 30, 2018 and December 31, 2017, respectively, at fair value)	1,651,930	1,011,004
Loans held for investment, mortgage finance	5,477,787	5,308,160
Loans held for investment (net of unearned income)	16,569,538	15,366,252
Less: Allowance for loan losses	190,306	184,655
Loans held for investment, net	21,857,019	20,489,757
Mortgage servicing rights, net	86,359	85,327
Premises and equipment, net	24,004	25,176
Accrued interest receivable and other assets	586,668	516,239
Goodwill and intangible assets, net	18,687	19,040
Total assets	27,127,107	25,075,645
Non-interest-bearing
Non-interest-bearing	7,031,460	7,812,660
Interest-bearing	13,354,177	11,310,520
Total deposits	20,385,637	19,123,180
Accrued interest payable	17,218	7,680
Other liabilities	215,909	182,212
Federal funds purchased and repurchase agreements	486,818	365,040
Other borrowings	3,200,000	2,800,000
Subordinated notes, net	281,677	281,406
Trust preferred subordinated debentures	113,406	113,406
Total liabilities	24,700,665	22,872,924
Stockholders’ equity:
Preferred stock, $.01 par value, $1,000 liquidation value; Authorized shares - 10,000,000; Issued shares – 6,000,000 shares issued at June 30, 2017 and December 31, 2016, respectively	150,000	150,000
Common stock, $.01 par value; Authorized shares - 100,000,000; Issued shares – 45,595,669 and 49,504,079 at June 30, 2017 and December 31, 2016, respectively	502	496
Additional paid-in capital	965,286	961,305
Retained earnings	1,312,038	1,090,500
Treasury stock – shares at cost: 417 at September 30, 2018 and December 31, 2017	(8)	(8)
Accumulated other comprehensive income, net of taxes	(1,376)	428
Total stockholders’ equity	2,426,442	2,202,721
Total liabilities and stockholders’ equity	$ 27,127,107	$ 25,075,645

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parentheticals) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Loans held for sale	$ 1,651,930	$ 1,007,695
Preferred stock, par value	$ 0.01	$ 0.01
Preferred Stock, shares authorized	10,000,000	10,000,000
Preferred Stock, shares issued	6,000,000	6,000,000
Common Stock, par value	$ 0.01	$ 0.01
Common Stock, shares authorized	100,000,000	100,000,000
Common Stock, shares issued	50,177,677	49,643,761
Treasury Stock, shares	417	417

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME AND OTHER COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Interest income
Interest and fees on loans	$ 291,189	$ 229,116	$ 814,500	$ 607,386
Investment securities	1,161	341	1,560	853
Federal funds sold and securities purchased under resale agreements	1,018	642	2,808	1,606
Interest-bearing deposits in other banks	8,386	7,544	23,607	19,935
Total interest income	301,754	237,643	842,475	629,780
Interest expense
Deposits	52,034	22,435	123,343	52,261
Federal funds purchased	1,800	891	4,434	1,869
Other borrowings	10,317	4,835	24,481	9,757
Subordinated notes	4,191	4,191	12,573	12,573
Trust preferred subordinated debentures	1,237	930	3,457	2,641
Total interest expense	69,579	33,282	168,288	79,101
Net interest income	232,175	204,361	674,187	550,679
Provision for credit losses	13,000	20,000	52,000	42,000
Net interest income after provision for credit losses	219,175	184,361	622,187	508,679
Non-interest income
Service charges on deposit accounts	3,477	3,211	9,619	9,323
Wealth management and trust fee income	2,065	1,627	5,996	4,386
Bank owned life insurance (BOLI) income	643	615	1,959	1,562
Brokered loan fees	6,141	6,152	17,124	17,639
Servicing income	4,987	4,486	15,446	10,387
Swap fees	1,355	647	4,269	3,404
Other	6,850	2,265	8,331	8,181
Total non-interest income	25,518	19,003	62,744	54,882
Non-interest expense
Salaries and employee benefits	77,327	67,882	222,268	194,039
Net occupancy expense	8,362	6,436	22,952	19,062
Marketing	10,214	7,242	29,127	18,349
Legal and professional	10,764	6,395	29,948	20,975
Communications and technology	7,435	6,002	21,211	24,414
FDIC insurance assessment	6,524	6,203	18,884	16,800
Servicing related expenses	4,207	3,897	12,379	8,329
Allowance and other carrying costs for other real estate owned (OREO)	(1,864)	105	467	315
Other	13,174	10,668	37,998	30,455
Total non-interest expense	136,143	114,830	395,234	332,738
Income before income taxes	108,550	88,534	289,697	230,823
Income tax expense	22,998	29,850	60,764	78,502
Net income	85,552	58,684	228,933	152,321
Preferred stock dividends	2,438	2,438	7,313	7,313
Net income available to common stockholders	83,114	56,246	221,620	145,008
Other comprehensive income (loss)
Change in net unrealized gain (loss) on available-for-sale debt securities arising during period, before-tax	(2,223)	52	(2,390)	22
Income tax expense (benefit) related to net unrealized gain on available-for-sale debt securities	(467)	18	(502)	8
Other comprehensive income (loss), net of tax	(1,756)	34	(1,888)	14
Comprehensive income	$ 83,796	$ 58,718	$ 227,045	$ 152,335
Basic earnings per common share (usd per share)	$ 1.66	$ 1.13	$ 4.45	$ 2.93
Diluted earnings per common share (usd per share)	$ 1.65	$ 1.12	$ 4.41	$ 2.89

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss), Net of Taxes
Stockholders' equity, beginning balance at Dec. 31, 2016	$ 2,009,557	$ 150,000	$ 495	$ 955,468	$ 903,187	$ (8)	$ 415
Shares, outstanding, beginning balance at Dec. 31, 2016		6,000,000	49,504,079			417
Comprehensive income:
Net income	152,321				152,321
Change in unrealized gain on available-for-sale securities, net of taxes	14						14
Total comprehensive income	152,335
Stock-based compensation expense recognized in earnings	5,717			5,717
Preferred stock dividend	(7,313)				(7,313)
Issuance of common stock related to warrants - value			33,595
Issuance of stock related to stock-based awards - value	(1,933)		$ (1)	(1,934)
Issuance of stock related to stock-based awards - shares			84,568
Stockholders' equity, ending balance at Sep. 30, 2017	2,158,363	$ 150,000	$ 496	959,251	1,048,195	$ (8)	429
Shares, outstanding, ending balance at Sep. 30, 2017		6,000,000	49,622,242			417
Stockholders' equity, beginning balance at Dec. 31, 2017	2,202,721	$ 150,000	$ 496	961,305	1,090,500	$ (8)	428
Shares, outstanding, beginning balance at Dec. 31, 2017		6,000,000	49,643,761			417
Comprehensive income:
Net income	228,933				228,933
Change in unrealized gain on available-for-sale securities, net of taxes	(1,888)						(1,888)
Total comprehensive income	227,045
Stock-based compensation expense recognized in earnings	6,383			6,383
Preferred stock dividend	(7,313)				(7,313)
Issuance of common stock related to warrants - value			436,855
Issuance of common stock related to warrants - shares	0		$ (5)	(5)
Issuance of stock related to stock-based awards - value	(2,396)		$ (1)	(2,397)
Issuance of stock related to stock-based awards - shares			97,061
Stockholders' equity, ending balance at Sep. 30, 2018	2,426,442	$ 150,000	$ 502	$ 965,286	1,312,038	$ (8)	(1,376)
Shares, outstanding, ending balance at Sep. 30, 2018		6,000,000	50,177,677			417
Impact of adoption of new accounting standards	$ 2				$ (82)		$ 84

CONSOLIDATED STATEMENTS OF ST_2

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parentheticals) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Stockholders' Equity [Abstract]
Income tax expense (benefit) related to net unrealized gain on available-for-sale debt securities	$ (467)	$ 18	$ (502)	$ 8

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities
Income from continuing operations	$ 228,933	$ 152,321
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	52,000	42,000
Depreciation and amortization	24,776	19,624
Increase (decrease) in valuation allowance on mortgage servicing rights	(2,823)	216
Bank owned life insurance (BOLI) income	(1,959)	(1,562)
Stock-based compensation expense	15,633	15,021
Purchases and originations of loans held for sale	(5,012,188)	(4,315,065)
Proceeds from sales and repayments of loans held for sale	4,321,485	4,282,910
Proceeds from sale of MSRs	22,439	0
Net loss on sale of loans held for sale and other assets	8,182	1,005
Technology write-off	0	5,285
Changes in operating assets and liabilities:
Accrued interest receivable and other assets	(79,107)	(68,672)
Accrued interest payable and other liabilities	33,920	8,434
Net cash provided by (used in) operating activities	(388,709)	141,517
Investing activities
Purchases of available-for-sale investment securities	(99,295)	(97,381)
Maturities and calls of available-for-sale securities	0	94,775
Principal payments received on available-for-sale securities	2,998	3,278
Originations of mortgage finance loans	(73,661,362)	(62,284,036)
Proceeds from pay-offs of mortgage finance loans	73,491,735	61,139,089
Net increase in loans held for investment, excluding mortgage finance loans	(1,248,423)	(1,856,253)
Purchase of premises and equipment, net	(5,655)	(9,056)
Proceeds from sale of foreclosed assets, net	13,645	767
Net cash used in investing activities	(1,506,357)	(3,008,817)
Financing activities
Net increase in deposits	1,262,457	2,064,426
Costs from issuance of stock related to stock-based awards and warrants	(2,396)	(1,933)
Preferred dividends paid	(7,313)	(7,313)
Net increase in other borrowings	400,000	500,000
Net increase in Federal funds purchased and repurchase agreements	121,778	(26,079)
Net cash provided by financing activities	1,774,526	2,529,101
Net decrease in cash and cash equivalents	(120,540)	(338,199)
Cash and cash equivalents at beginning of period	2,905,591	2,839,352
Cash and cash equivalents at end of period	2,785,051	2,501,153
Supplemental disclosures of cash flow information:
Cash paid during the period for interest	158,750	80,037
Cash paid during the period for income taxes	64,225	72,485
Transfers from loans/leases to OREO and other repossessed assets	$ 0	$ 0

OPERATIONS AND SUMMARY OF SIGNI

OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Operations and summary of significant accounting policies	OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Organization and Nature of Business Texas Capital Bancshares, Inc. (the “Company”), a Delaware corporation, was incorporated in November 1996 and commenced banking operations in December 1998. The consolidated financial statements of the Company include the accounts of Texas Capital Bancshares, Inc. and its wholly owned subsidiary, Texas Capital Bank, National Association (the “Bank”). We serve the needs of commercial businesses and successful professionals and entrepreneurs located in Texas as well as operate several lines of business serving a regional and national clientèle of commercial borrowers. We are primarily a secured lender with a majority of our loans being made to businesses headquartered or with operations in Texas. At the same time, our national lines of business continue to provide specialized lending products,as well as treasury services, deposit products and other complementary banking services, to businesses throughout the United States. Basis of Presentation Our accounting and reporting policies conform to accounting principles generally accepted in the United States (“GAAP”) and to generally accepted practices within the banking industry. Certain prior period balances have been reclassified to conform to the current period presentation. The consolidated interim financial statements are unaudited and certain information and footnote disclosures presented in accordance with GAAP have been condensed or omitted. In the opinion of management, the interim financial statements include all normal and recurring adjustments and the disclosures made are adequate to make the interim financial information not misleading. The consolidated financial statements have been prepared in accordance with GAAP for interim financial information and the instructions to Form 10-Q adopted by the Securities and Exchange Commission (“SEC”). Accordingly, the financial statements do not include all of the information and footnotes required by GAAP for complete financial statements and should be read in conjunction with our consolidated financial statements, and notes thereto, for the year ended December 31, 2017 , included in our Annual Report on Form 10-K filed with the SEC on February 14, 2018 (the “ 2017 Form 10-K”). Operating results for the interim periods disclosed herein are not necessarily indicative of the results that may be expected for a full year or any future period. Accounting Changes ASU 2018-02 " Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income" ("ASU 2018-02") allows a reclassification from accumulated other comprehensive income (loss) ("AOCI") to retained earnings for the stranded tax effects caused by the revaluation of deferred taxes resulting from the newly enacted corporate tax rate in the Tax Cuts and Jobs Act. The ASU is effective in years beginning after December 15, 2018, but permits early adoption in a period for which financial statements have not yet been issued. We have elected to early adopt the ASU as of January 1, 2018. The adoption of the guidance resulted in an insignificant cumulative-effect adjustment that decreased retained earnings and increased AOCI in the first quarter of 2018. ASU 2016-15 "Statement of Cash Flows (Topic 230)" ("ASU 2016-15") is intended to reduce the diversity in practice around how certain transactions are classified within the statement of cash flows. ASU 2016-15 became effective for us on January 1, 2018 and did not have a significant impact on our financial statements. ASU 2016-01 "Financial Instruments - Overall (Subtopic 825-10): Recognition of Financial Assets and Financial Liabilities, ("ASU 2016-01") makes targeted amendments to the guidance for recognition, measurement, presentation and disclosure of financial instruments. ASU 2016-01 requires equity investments, other than equity method investments, to be measured at fair value with changes in fair value recognized in net income. The ASU requires a cumulative-effect adjustment to retained earnings as of the beginning of the reporting period of adoption to reclassify the cumulative change in fair value of equity securities previously recognized in AOCI. ASU 2016-01 became effective for us on January 1, 2018. The adoption of the guidance resulted in an insignificant cumulative-effect adjustment that increased retained earnings, with offsetting related adjustments to deferred taxes and AOCI. ASU 2016-01 also emphasizes the existing requirement to use exit prices to measure fair value for disclosure purposes and clarifies that entities should not make use of a practicability exception in determining the fair value of loans. Accordingly, we refined the calculation used to determine the disclosed fair value of our loans held for investment portfolio as part of adopting this standard. The refined calculation did not have a significant impact on our fair value disclosures. See Note 11 - Fair Value Disclosures. ASU 2014-09 "Revenue from Contracts with Customers (Topic 606)" ("ASU 2014-09") implements a common revenue standard that clarifies the principles for recognizing revenue. The core principle of ASU 2014-09 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 establishes a five-step model which entities must follow to recognize revenue and removes inconsistencies and weaknesses in existing guidance. The guidance does not apply to revenue associated with financial instruments, including loans and investment securities that are accounted for under other GAAP, which comprises a significant portion of our revenue stream. ASU 2014-09 became effective for us on January 1, 2018 and had no material effect on how we recognize revenue or to our consolidated financial statements and disclosures. See below for additional information related to revenue generated from contracts with customers. Revenue Recognition Accounting Standards Codification ("ASC") 606, Revenue from Contracts with Customers ("ASC 606"), establishes principles for reporting information about the nature, amount, timing and uncertainty of revenue and cash flows arising from the entity's contracts to provide goods or services to customers. The core principle requires an entity to recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration that it expects to be entitled to receive in exchange for those goods or services recognized as performance obligations are satisfied. The majority of our revenue-generating transactions are not subject to ASC 606, including revenue generated from financial instruments, such as our loans, letters of credit, derivatives and investment securities, as well as revenue related to our mortgage servicing activities, as these activities are subject to other GAAP discussed elsewhere within our disclosures. Descriptions of our revenue-generating activities that are within the scope of ASC 606, which are presented in our income statements as components of non-interest income are as follows: • Service charges on deposit accounts - these represent general service fees for monthly account maintenance and activity- or transaction-based fees and consist of transaction-based revenue, time-based revenue (service period), item-based revenue or some other individual attribute-based revenue. Revenue is recognized when our performance obligation is completed which is generally monthly for account maintenance services or when a transaction has been completed (such as a wire transfer). Payments for such performance obligations are generally received at the time the performance obligations are satisfied. • Wealth management and trust fee income - this represents monthly fees due from wealth management customers as consideration for managing the customers' assets. Wealth management and trust services include custody of assets, investment management, escrow services, fees for trust services and similar fiduciary activities. Revenue is recognized when our performance obligation is completed each month, which is generally the time that payment is received. Also included are fees received from third party broker-dealers as part of a revenue-sharing agreement for fees earned from customers that we refer to the third party. These fees are paid to us by the third party on a quarterly basis and recognized ratably throughout the quarter as our performance obligation is satisfied. • Brokered loan fees - these represent fees for the administration and funding of purchased mortgage loan interests as well as facility renewal and application fees received from mortgage originator customers in our warehouse lending business. Also included are fees received from independent correspondent mortgage lenders as consideration for our purchase of individual residential mortgage loans through our Mortgage Correspondent Aggregation ("MCA") business. Revenue related to the warehouse lending business is recognized when the related loan interest is disposed (i.e., through sale or payoff) or upon receipt of the facility renewal or application. Revenue related to our MCA business is recognized at the time a loan is purchased. • Other non-interest income primarily includes items such as letter of credit fees, gains on sale of loans held for sale and servicing fees related to the MCA program, none of which are subject to the requirements of ASC 606. Investment Securities Investment securities include available-for-sale debt securities and equity securities at fair value. Debt Securities Debt securities are classified as trading, available-for-sale or held-to-maturity. Management classifies debt securities at the time of purchase and re-assesses such designation at each balance sheet date; however, transfers between categories from this re-assessment are rare. Trading Account Debt securities acquired for resale in anticipation of short-term market movements are classified as trading, with realized and unrealized gains and losses recognized in income. To date, we have not had any activity in our trading account. Held-to-Maturity Debt securities are classified as held to maturity when we have the positive intent and ability to hold the securities to maturity. Held-to-maturity securities are stated at amortized cost. Debt securities not classified as held-to-maturity or trading are classified as available-for-sale. Available-for-Sale Available-for-sale debt securities are stated at fair value, with the unrealized gains and losses reported as a separate component of AOCI, net of tax. The amortized cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity, or in the case of mortgage-backed securities, over the estimated life of the security. Such amortization and accretion is included in interest income from securities. Realized gains and losses and declines in value judged to be other-than-temporary are included in gain (loss) on sale of securities. In estimating other-than-temporary impairment losses, we consider, among other things, length of time and the extent to which the fair value have been less than cost, the financial condition and near-term prospects of the issuer and the intent and our ability to retain our investment in the issuer for a period of time sufficient to allow for any time anticpated recovery in fair value. The cost of securities sold is based on the specific identification method. All debt securities are available-for-sale as of September 30, 2018 and December 31, 2017 . Equity Securities Beginning January 1, 2018, upon adoption of ASU 2016-01, equity securities with readily determinable fair values are stated at fair value with realized and unrealized gains and losses reported in other non-interest income in the consolidated statements of income and other comprehensive income. For periods prior to January 1, 2018, equity securities were classified as available-for-sale and stated at fair value with unrealized gains and losses reported as a separate component of AOCI, net of tax. Equity securities without readily determinable fair values are recorded at cost less any impairment, if any. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates. The allowance for loan losses, the fair value of stock-based compensation awards, the fair value of mortgage servicing rights ("MSRs") and the status of contingencies are particularly susceptible to significant change.

EARNINGS PER COMMON SHARE

EARNINGS PER COMMON SHARE	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
EARNINGS PER COMMON SHARE	EARNINGS PER COMMON SHARE The following table presents the computation of basic and diluted earnings per share (in thousands except share data): Three months ended Nine months ended 2018 2017 2018 2017 Numerator: Net income $ 85,552 $ 58,684 $ 228,933 $ 152,321 Preferred stock dividends 2,438 2,438 7,313 7,313 Net income available to common stockholders 83,114 56,246 $ 221,620 145,008 Denominator: Denominator for basic earnings per share—weighted average shares 50,163,433 49,607,028 49,853,515 49,573,456 Effect of employee stock-based awards (1) 207,391 214,468 240,376 235,011 Effect of warrants to purchase common stock 10,525 429,370 115,537 431,551 Denominator for dilutive earnings per share—adjusted weighted average shares and assumed conversions 50,381,349 50,250,866 50,209,428 50,240,018 Basic earnings per common share $ 1.66 $ 1.13 $ 4.45 $ 2.93 Diluted earnings per common share $ 1.65 $ 1.12 $ 4.41 $ 2.89 (1) SARs and RSUs outstanding of 4,000 at September 30, 2018 and 6,200 at September 30, 2017 have not been included in diluted earnings per share because to do so would have been anti-dilutive for the periods presented.

SECURITIES

SECURITIES	9 Months Ended
	Sep. 30, 2018
Available-for-sale Securities [Abstract]
INVESTMENT SECURITIES	Available-for-Sale Debt Securities The following is a summary of available-for-sale debt securities (in thousands): September 30, 2018 Amortized Gross Gross Estimated Residential mortgage-backed securities $ 7,299 $ 410 $ — $ 7,709 Tax-exempt asset-backed securities 95,521 — (2,152 ) 93,369 $ 102,820 $ 410 $ (2,152 ) $ 101,078 December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Residential mortgage-backed securities $ 10,297 $ 648 $ — $ 10,945 During the third quarter of 2018, we purchased a $95.5 million tax-exempt security backed with underlying cash flows from municipal revenue bonds. The security was recorded as available-for-sale upon purchase and subsequently marked to fair value as of quarter end. The amortized cost and estimated fair value of available-for-sale debt securities are presented below by contractual maturity (in thousands, except percentage data): September 30, 2018 Less Than After One After Five After Ten Total Residential mortgage-backed securities: (1) Amortized cost 12 1,727 — 5,560 7,299 Estimated fair value 13 1,846 — 5,850 7,709 Weighted average yield (3) 6.23 % 5.55 % — % 3.79 % 4.21 % Tax-exempt asset-backed securities:(1) Amortized cost — — — 95,521 95,521 Estimated fair value — — — 93,369 93,369 Weighted average yield(2)(3) — % — % — % 4.25 % 4.25 % Total available-for-sale debt securities: Amortized cost $ 102,820 Estimated fair value $ 101,078 December 31, 2017 Less Than After One After Five After Ten Total Residential mortgage-backed securities:(1) Amortized cost $ 409 $ 819 $ 1,502 $ 7,567 $ 10,297 Estimated fair value 418 916 1,636 7,975 10,945 Weighted average yield(3) 4.59 % 6.02 % 5.32 % 3.45 % 3.97 % (1) Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without prepayment penalties. (2) Yields have been adjusted to a tax equivalent basis assuming a 21% federal tax rate. (3) Yields are calculated based on amortized cost. The following table discloses as of September 30, 2018 our available-for-sale debt securities that have been in a continuous unrealized loss position for less than 12 months and those that have been in a continuous unrealized loss position for 12 or more months (in thousands): September 30, 2018 Less Than 12 Months 12 Months or Longer Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Tax-exempt asset-backed securities $ 93,369 $ (2,152 ) $ — $ — $ 93,369 $ (2,152 ) At September 30, 2018 , we had three available-for-sale debt securities in an unrealized loss position. We do not believe these unrealized losses are "other than temporary." We have evaluated the near-term prospects of the investments in relation to the severity and duration of the impairment and based on that evaluation we have determined that we have the ability and intent to hold the investments until recovery of fair value. At December 31, 2017 , we did not have any available-for-sale debt securities in an unrealized loss position. At September 30, 2018 , available-for-sale debt securities with carrying values of $1.9 million and $5.1 million were pledged to secure certain deposits and repurchase agreements, respectively. Equity Securities Equity securities consist of Community Reinvestment Act funds and investments related to our non-qualified deferred compensation plan. At September 30, 2018 and December 31, 2017 , we had $16.3 million and $12.6 million , respectively, in equity securities recorded at fair value. Prior to January 1, 2018, equity securities were stated at fair value with unrealized gains and losses reported as a separate component of AOCI, net of tax. At December 31, 2017 , net unrealized gains of $10,000 had been recognized in AOCI. On January 1, 2018, these unrealized gains and losses were reclassified out of AOCI and into retained earnings with subsequent changes in fair value being recognized in other non-interest income. The following is a summary of unrealized and realized gains and losses recognized in net income on equity securities during the three and nine months ended September 30, 2018 (in thousands): Three months ended Nine months ended September 30, 2018 September 30, 2018 Net gains and (losses) recognized during the period on equity securities $ 253 $ 149 Less: Net gains and (losses) recognized during the period on equity securities sold during the period 18 180 Unrealized gains and (losses) recognized during the reporting period on equity securities still held at the reporting date $ 235 $ (31 )

LOANS AND ALLOWANCE FOR LOAN LO

LOANS AND ALLOWANCE FOR LOAN LOSSES	9 Months Ended
	Sep. 30, 2018
Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract]
Loans and allowance for credit losses	LOANS HELD FOR INVESTMENT AND ALLOWANCE FOR LOAN LOSSES At September 30, 2018 and December 31, 2017 , loans held for investment were as follows (in thousands): September 30, December 31, Commercial $ 10,116,945 $ 9,189,811 Mortgage finance 5,477,787 5,308,160 Construction 2,263,463 2,166,208 Real estate 3,924,682 3,794,577 Consumer 51,692 48,684 Leases 319,411 264,903 Gross loans held for investment 22,153,980 20,772,343 Deferred income (net of direct origination costs) (106,655 ) (97,931 ) Allowance for loan losses (190,306 ) (184,655 ) Total loans held for investment, net $ 21,857,019 $ 20,489,757 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. We have agreements with mortgage lenders and purchase interests in individual loans they originate. The ownership interests collateralizing our mortgage finance loans are typically held on our balance sheet for 10 to 20 days, and substantially all loans are conforming loans. Substantially all mortgage loans are underwritten consistently with established programs for permanent financing with financially sound investors. Balances as of September 30, 2018 and December 31, 2017 are stated net of $174.1 million and $171.2 million of 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 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 loan defaults, increasing risk of exposure to classification, non-performing status, reserve allocation and actual credit loss and foreclosure. These loans typically have floating rates and require 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. 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 September 30, 2018 and December 31, 2017 , we had a blanket floating lien on certain real estate-secured loans, mortgage finance loans and certain investment securities used as collateral for Federal Home Loan Bank 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 September 30, 2018 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 September 30, 2018 and December 31, 2017 (in thousands): September 30, 2018 Commercial Mortgage Finance Construction Real Estate Consumer Leases Total Grade: Pass $ 9,851,525 $ 5,477,787 $ 2,250,650 $ 3,845,393 $ 50,064 $ 318,969 $ 21,794,388 Special mention 96,168 — 12,813 44,486 — 442 153,909 Substandard-accruing 64,295 — — 32,288 1,568 — 98,151 Non-accrual 104,957 — — 2,515 60 — 107,532 Total loans held for investment $ 10,116,945 $ 5,477,787 $ 2,263,463 $ 3,924,682 $ 51,692 $ 319,411 $ 22,153,980 December 31, 2017 Commercial Mortgage Finance Construction Real Estate Consumer Leases Total Grade: Pass $ 8,967,471 $ 5,308,160 $ 2,152,654 $ 3,706,541 $ 48,591 $ 249,865 $ 20,433,282 Special mention 19,958 — 13,554 53,652 — 495 87,659 Substandard-accruing 102,651 — — 32,671 93 14,543 149,958 Non-accrual 99,731 — — 1,713 — — 101,444 Total loans held for investment $ 9,189,811 $ 5,308,160 $ 2,166,208 $ 3,794,577 $ 48,684 $ 264,903 $ 20,772,343 The following table details activity in the allowance for loan losses by portfolio segment for the 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. September 30, 2018 (in thousands) Commercial Mortgage Finance Construction Real Estate Consumer Leases Additional Qualitative Reserve Total Beginning balance $ 118,806 $ — $ 19,273 $ 34,287 $ 357 $ 3,542 $ 8,390 $ 184,655 Provision for loan losses 55,808 — 331 (1,635 ) 757 (1,425 ) (3,048 ) 50,788 Charge-offs 45,273 — — — 767 319 — 46,359 Recoveries 1,069 — — 43 78 32 — 1,222 Net charge-offs (recoveries) 44,204 — — (43 ) 689 287 — 45,137 Ending balance $ 130,410 $ — $ 19,604 $ 32,695 $ 425 $ 1,830 $ 5,342 $ 190,306 Period end amount allocated to: Loans individually evaluated for impairment $ 30,855 $ — $ — $ 70 $ 10 $ — $ — $ 30,935 Loans collectively evaluated for impairment 99,555 — 19,604 32,625 415 1,830 5,342 159,371 Ending balance $ 130,410 $ — $ 19,604 $ 32,695 $ 425 $ 1,830 $ 5,342 $ 190,306 September 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 21,388 — 4,431 12,948 221 2,774 1,899 43,661 Charge-offs 32,146 — 59 290 180 — — 32,675 Recoveries 3,574 — 104 74 56 9 — 3,817 Net charge-offs (recoveries) 28,572 — (45 ) 216 124 (9 ) — 28,858 Ending balance $ 121,584 $ — $ 17,620 $ 31,881 $ 338 $ 3,907 $ 7,599 $ 182,929 Period end amount allocated to: Loans individually evaluated for impairment $ 24,410 $ — $ — $ 26 $ — $ — $ — $ 24,436 Loans collectively evaluated for impairment 97,174 — 17,620 31,855 338 3,907 7,599 158,493 Ending balance $ 121,584 $ — $ 17,620 $ 31,881 $ 338 $ 3,907 $ 7,599 $ 182,929 The table below presents the activity in the allowance for off-balance sheet credit losses related to unfunded commitments for the three and nine months ended September 30, 2018 and 2017 (in thousands). This allowance is recorded in other liabilities in the consolidated balance sheet. Three months ended September 30, Nine months ended September 30, 2018 2017 2018 2017 Beginning balance $ 10,458 $ 9,205 $ 9,071 $ 11,422 Provision for off-balance sheet credit losses (175 ) 556 1,212 (1,661 ) Ending balance $ 10,283 $ 9,761 $ 10,283 $ 9,761 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. The decrease in the additional qualitative reserve at September 30, 2018 as compared to December 31, 2017 was primarily related to the resolution of remaining uncertainty regarding the impact to our loan portfolio from Hurricanes Harvey and Irma. We believe the level of additional qualitative reserves at September 30, 2018 is warranted due to uncertainties and unpredictable factors that have 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 uncertainties or unpredictable events. Our recorded investment in loans as of September 30, 2018 , December 31, 2017 and September 30, 2017 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): September 30, 2018 Commercial Mortgage Finance Construction Real Estate Consumer Leases Total Loans individually evaluated for impairment $ 105,522 $ — $ — $ 9,057 $ 60 $ — $ 114,639 Loans collectively evaluated for impairment 10,011,423 5,477,787 2,263,463 3,915,625 51,632 319,411 22,039,341 Total $ 10,116,945 $ 5,477,787 $ 2,263,463 $ 3,924,682 $ 51,692 $ 319,411 $ 22,153,980 December 31, 2017 Commercial Mortgage Finance Construction Real Estate Consumer Leases Total Loans individually evaluated for impairment $ 100,676 $ — $ — $ 2,008 $ — $ — $ 102,684 Loans collectively evaluated for impairment 9,089,135 5,308,160 2,166,208 3,792,569 48,684 264,903 20,669,659 Total $ 9,189,811 $ 5,308,160 $ 2,166,208 $ 3,794,577 $ 48,684 $ 264,903 $ 20,772,343 September 30, 2017 Commercial Mortgage Finance Construction Real Estate Consumer Leases Total Loans individually evaluated for impairment $ 117,426 $ — $ — $ 2,117 $ — $ — $ 119,543 Loans collectively evaluated for impairment 8,693,399 5,642,285 2,099,355 3,681,447 70,436 259,720 20,446,642 Total $ 8,810,825 $ 5,642,285 $ 2,099,355 $ 3,683,564 $ 70,436 $ 259,720 $ 20,566,185 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, 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 both September 30, 2018 and December 31, 2017 , none of our non-accrual loans were earning interest income on a cash basis. 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 September 30, 2018 and December 31, 2017 (in thousands): September 30, 2018 Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized With no related allowance recorded: Commercial Business loans $ 14,669 $ 21,428 $ — $ 16,045 $ 133 Energy 12,777 13,953 — 18,653 — Construction Market risk — — — — — Real estate Market risk — — — — — Commercial 7,557 7,557 — 1,787 — Secured by 1-4 family 1,263 1,263 — 561 — Consumer — — — — — Leases — — — — — Total impaired loans with no allowance recorded $ 36,266 $ 44,201 $ — $ 37,046 $ 133 With an allowance recorded: Commercial Business loans $ 59,618 $ 78,304 $ 24,180 $ 39,880 $ — Energy 18,458 19,718 6,675 27,312 — Construction Market risk — — — — — Real estate Market risk — — — 66 — Commercial — — — 111 — Secured by 1-4 family 237 237 70 171 — Consumer 60 60 10 53 — Leases — — — 367 — Total impaired loans with an allowance recorded $ 78,373 $ 98,319 $ 30,935 $ 67,960 $ — Combined: Commercial Business loans $ 74,287 $ 99,732 $ 24,180 $ 55,925 $ 133 Energy 31,235 33,671 6,675 45,965 — Construction Market risk — — — — — Real estate Market risk — — — 66 — Commercial 7,557 7,557 — 1,898 — Secured by 1-4 family 1,500 1,500 70 732 — Consumer 60 60 10 53 — Leases — — — 367 — Total impaired loans $ 114,639 $ 142,520 $ 30,935 $ 105,006 $ 133 December 31, 2017 Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized With no related allowance recorded: Commercial Business loans $ 16,835 $ 18,257 $ — $ 22,964 $ — Energy 21,426 22,602 — 36,579 — Construction Market risk — — — — — Real estate Market risk — — — — — Commercial 1,096 1,096 — 2,166 — Secured by 1-4 family — — — — — Consumer — — — — — Leases — — — — — Total impaired loans with no allowance recorded $ 39,357 $ 41,955 $ — $ 61,709 $ — With an allowance recorded: Commercial Business loans $ 18,645 $ 19,020 $ 2,544 $ 16,960 $ — Energy 43,770 55,875 21,772 50,867 6 Construction Market risk — — — 27 — Real estate Market risk 295 295 6 485 — Commercial 499 499 75 166 — Secured by 1-4 family 118 118 20 516 — Consumer — — — 33 — Leases — — — 14 — Total impaired loans with an allowance recorded $ 63,327 $ 75,807 $ 24,417 $ 69,068 $ 6 Combined: Commercial Business loans $ 35,480 $ 37,277 $ 2,544 $ 39,924 $ — Energy 65,196 78,477 21,772 87,446 6 Construction Market risk — — — 27 — Real estate Market risk 295 295 6 485 — Commercial 1,595 1,595 75 2,332 — Secured by 1-4 family 118 118 20 516 — Consumer — — — 33 — Leases — — — 14 — Total impaired loans $ 102,684 $ 117,762 $ 24,417 $ 130,777 $ 6 Average impaired loans outstanding during the nine months ended September 30, 2018 and 2017 totaled $105.0 million and $ 135.9 million , respectively. The table below provides an age analysis of our loans held for investment as of September 30, 2018 (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 $ 51,154 $ 4,304 $ 9,882 $ 65,340 $ 73,722 $ 8,488,962 $ 8,628,024 Energy 13,000 2,281 — 15,281 31,235 1,442,405 1,488,921 Mortgage finance loans — — — — — 5,477,787 5,477,787 Construction Market risk — — — — — 2,182,653 2,182,653 Commercial — — — — — 53,116 53,116 Secured by 1-4 family — — — — — 27,694 27,694 Real estate Market risk 3,471 — 1,413 4,884 — 2,759,177 2,764,061 Commercial 4,192 — — 4,192 1,015 814,646 819,853 Secured by 1-4 family 1,538 85 — 1,623 1,500 337,645 340,768 Consumer — — — — 60 51,632 51,692 Leases 92 — — 92 — 319,319 319,411 Total loans held for investment $ 73,447 $ 6,670 $ 11,295 $ 91,412 $ 107,532 $ 21,955,036 $ 22,153,980 (1) Loans past due 90 days and still accruing includes premium finance loans of $8.2 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 September 30, 2018 and December 31, 2017 , we did not have any loans considered restructured that were not on non-accrual. Of the non-accrual loans at September 30, 2018 and December 31, 2017 , $22.5 million and $18.8 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 the loans that were restructured during the nine months ended September 30, 2018 and 2017 (in thousands): As of and for the nine months ended September 30, 2018 Number of Restructured Loans Balance at Restructure Balance at Period-End Energy loans 5 $ 12,358 $ 12,332 Commercial business loans 2 2,582 2,582 Total new restructured loans 7 $ 14,940 $ 14,914 As of and for the nine months ended September 30, 2017 Number of Restructured Loans Balance at Restructure Balance at Period-End Energy loans 1 $ 1,070 $ — Commercial business loans 1 599 721 Total new restructured loans 2 $ 1,669 $ 721 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 September 30, 2018 or 2017 . The following table provides information on how loans were modified as restructured during the nine months ended September 30, 2018 and 2017 (in thousands): Nine months ended September 30, 2018 2017 Extended maturity $ — $ 721 Adjusted payment schedule 14,914 — Total $ 14,914 $ 721 As of September 30, 2018 and 2017 , we did not have any loans that were restructured within the last 12 months that subsequently defaulted.

OREO AND VALUATION ALLOWANCE FO

OREO AND VALUATION ALLOWANCE FOR LOSSES ON OREO	9 Months Ended
	Sep. 30, 2018
Real Estate Owned, Disclosure of Detailed Components [Abstract]
OREO AND VALUATION ALLOWANCE FOR LOSSES ON OREO	OREO AND VALUATION ALLOWANCE FOR LOSSES ON OREO The table below presents a summary of the activity related to OREO (in thousands): Three months ended September 30, Nine months ended September 30, 2018 2017 2018 2017 Beginning balance $ 9,526 $ 18,689 $ 11,742 $ 18,961 Additions — — — — Sales (11,447 ) (457 ) (11,663 ) (729 ) Valuation allowance for OREO 2,000 (101 ) — (101 ) Ending balance $ 79 $ 18,131 $ 79 $ 18,131 During the third quarter of 2018, we sold our largest OREO property and recorded a $2.0 million gain on sale, as well as a reversal of a $2.0 million valuation allowance that was recorded on the property during the first quarter of 2018. The gain on sale was recorded in other non-interest income and the reversal of the valuation allowance was recorded in other non-interest expense. When foreclosure occurs, the acquired asset is recorded at fair value less selling costs, generally based on appraised value, which may result in partial charge-off of the loan. Subsequent write-downs required for declines in value are recorded through a valuation allowance or taken directly against the asset and charged to other non-interest expense.

CERTAIN TRANSFERS OF FINANCIAL

CERTAIN TRANSFERS OF FINANCIAL ASSETS	9 Months Ended
	Sep. 30, 2018
Transfers and Servicing [Abstract]
CERTAIN TRANSFERS OF FINANCIAL ASSETS	CERTAIN TRANSFERS OF FINANCIAL ASSETS Through our MCA business, we commit to purchase residential mortgage loans from independent correspondent lenders and deliver those loans into the secondary market via whole loan sales to independent third parties or in securitization transactions to Ginnie Mae and government sponsored entities ("GSEs") such as Fannie Mae and Freddie Mac. We have elected to carry these loans at fair value based on sales commitments, market quotes or pricing models. Gains and losses on the sale of mortgage loans held for sale and changes in the fair value of the loans held for sale and related derivatives are included in other non-interest income on the consolidated statements of income and other comprehensive income. For the nine months ended September 30, 2018 and 2017 , losses totaled $7.8 million and $1.0 million , respectively. Residential mortgage loans held for sale are subject to both credit and interest rate risk. Credit risk is managed through underwriting policies and procedures, including collateral requirements, which are generally accepted by the secondary loan markets. Exposure to interest rate fluctuations is partially mitigated through forward sales contracts, which set the price for loans that will be delivered in the next 60 to 90 days. The table below presents the unpaid principal balance of loans held for sale and related fair values at September 30, 2018 and December 31, 2017 (in thousands): September 30, 2018 December 31, 2017 Outstanding balance(1) $ 1,658,630 $ 1,009,271 Fair value(1) 1,651,930 1,007,695 Fair value over/(under) outstanding balance $ (6,700 ) $ (1,576 ) (1) Does not include $3.3 million of Small Business Administration ("SBA") loans held for sale carried at lower of cost or market as of December 31, 2017 . No loans held for sale were on non-accrual as of September 30, 2018 or December 31, 2017 . At September 30, 2018 and December 31, 2017 , we had $25.2 million and $19.7 million , respectively, in outstanding balances of loans held for sale that were 90 days or more past due. The $25.2 million loans held for sale that were 90 days or more past due at September 30, 2018 included $19.8 million in loans guaranteed by U.S. government agencies that were repurchased out of Ginnie Mae securities and recorded as loans held for sale, at fair value, on the balance sheet. Interest on these past due loans accrues at the debenture rate guaranteed by the U.S. government. Also included in the $25.2 million were $5.0 million in loans that, pursuant to Ginnie Mae servicing guidelines, we have the unilateral right, but not the obligation, to repurchase if defined delinquent loan criteria are met, and therefore must record as loans held for sale on our balance sheet regardless of whether the repurchase option has been exercised. The comparable balances at December 31, 2017 were no loans repurchased and $19.0 million in loans for which we have the unilateral right but not the obligation to repurchase. The table below presents a reconciliation of the changes in loans held for sale for the nine months ended September 30, 2018 and 2017 (in thousands): Nine months ended September 30, 2018 2017 Beginning balance $ 1,011,004 $ 968,929 Loans purchased 5,012,188 4,315,065 Payments and loans sold (4,366,138 ) (4,337,919 ) Change in fair value (5,124 ) 9,908 Ending balance $ 1,651,930 $ 955,983 We generally retain the right to service the loans sold, creating MSRs which are recorded as assets on our balance sheet. A summary of MSR activity for the nine months ended September 30, 2018 and 2017 is as follows (in thousands): Nine months ended September 30, 2018 2017 MSRs: Balance, beginning of year $ 88,150 $ 28,536 Capitalized servicing rights 32,871 54,614 Amortization (7,920 ) (5,304 ) Sales (26,742 ) — Balance, end of period $ 86,359 $ 77,846 Valuation allowance: Balance, beginning of year $ 2,823 $ — Increase (decrease) in valuation allowance (2,823 ) 216 Balance, end of period $ — $ 216 MSRs, net(1) $ 86,359 $ 77,630 MSRs, fair value $ 98,391 $ 78,940 (1) MSRs are reported on the consolidated balance sheets at amortized cost, less a valuation allowance if the fair value of identified strata, determined by interest rates, within the MSR portfolio are determined to have a fair value that is less than amortized cost. We completed a sale of Ginnie Mae MSRs in the first quarter of 2018. In anticipation of this sale, the fair value of the MSRs at December 31, 2017 was adjusted, resulting in a $2.8 million impairment charge taken in the fourth quarter of 2017 that was subsequently reversed upon completion of the sale in the first quarter of 2018. At September 30, 2018 and December 31, 2017 , our servicing portfolio of residential mortgage loans had an outstanding principal balance of $7.3 billion and $7.0 billion , respectively. In connection with the servicing of these loans, we hold deposits in the names of the investors who own the loans representing escrow funds for taxes and insurance, as well as collections in transit to the investors. These escrow funds are segregated and held in separate non-interest-bearing accounts at the Bank. These deposits, included in total non-interest-bearing deposits on the consolidated balance sheets, were $96.5 million at September 30, 2018 and $73.4 million at December 31, 2017 . The estimated fair value of the MSR assets is obtained from an independent third party and reviewed by management on a quarterly basis. MSRs typically do not trade in an active, open market with readily observable prices; as such, the fair value of MSRs is determined using a discounted cash flow model to calculate the present value of the estimated future net servicing income. The assumptions utilized in the discounted cash flow model are based on market data for comparable assets, where available. Each quarter, management and the independent third party discuss the key assumptions used in the discounted cash flow model and make adjustments as necessary to estimate the fair value of the MSRs. As of September 30, 2018 and December 31, 2017 , management used the following assumptions to determine the fair value of MSRs: September 30, 2018 December 31, 2017 Average discount rates 9.62 % 9.90 % Expected prepayment speeds 8.31 % 9.99 % Weighted average life, in years 7.9 7.0 A sensitivity analysis of changes in the fair value of our MSR portfolio resulting from certain key assumptions is presented in the following table (in thousands): September 30, 2018 December 31, 2017 50 bp adverse change in prepayment speed $ (11,581 ) $ (11,896 ) 100 bp adverse change in prepayment speed (24,868 ) (28,226 ) These sensitivities are hypothetical and actual results may differ materially due to a number of factors. The effect on fair value of a 10% variation in assumptions generally cannot be determined with confidence because the relationship of the change in assumptions to the fair value may not be linear. Additionally, the impact of a variation in a particular assumption on the fair value is calculated while holding other assumptions constant. In reality, changes in one factor may be correlated with changes in other factors, which could impact the sensitivity analysis as presented. In conjunction with the sale and securitization of loans held for sale, we may be exposed to liability resulting from recourse agreements and repurchase agreements. If it is determined subsequent to our sale of a loan that the loan sold is in breach of the representations or warranties made in the applicable sale agreement, we may have an obligation to either (a) repurchase the loan for the unpaid principal balance, accrued interest and related advances, (b) indemnify the purchaser against any loss it suffers or (c) make the purchaser whole for the economic benefits of the loan. Our repurchase, indemnification and make whole obligations vary based upon the terms of the applicable agreements, the nature of the asserted breach and the status of the mortgage loan at the time a claim is made. We establish reserves for estimated losses of this nature inherent in the origination of mortgage loans by estimating the losses inherent in the population of all loans sold based on trends in claims and actual loss severities experienced. The reserve includes accruals for probable contingent losses in addition to those identified in the pipeline of claims received. The estimation process is designed to include amounts based on any actual losses experienced from actual repurchase activity. Our estimated exposure related to loans previously sold and currently held for sale was $1.6 million at September 30, 2018 and $1.3 million at December 31, 2017 and is recorded in other liabilities in the consolidated balance sheets. We had $187,000 in losses due to repurchase, indemnification and make-whole obligations during the nine months ended September 30, 2018 and $14,000 in losses during the nine months ended September 30, 2017 .

FINANCIAL INSTRUMENTS WITH OFF-

FINANCIAL INSTRUMENTS WITH OFF-BALANCE SHEET RISK	9 Months Ended
	Sep. 30, 2018
Risks and Uncertainties [Abstract]
FINANCIAL INSTRUMENTS WITH OFF-BALANCE SHEET RISK	FINANCIAL INSTRUMENTS WITH OFF-BALANCE SHEET RISK The Bank is a party to financial instruments with off-balance sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments include commitments to extend credit and standby letters of credit that involve varying degrees of credit risk in excess of the amount recognized in the consolidated balance sheets. The Bank’s exposure to credit loss in the event of non-performance by the other party to the financial instrument for commitments to extend credit and standby letters of credit is represented by the contractual amount of these instruments. The Bank uses the same credit policies in making commitments and conditional obligations as it does for on-balance sheet instruments. The amount of collateral obtained, if deemed necessary, is based on management’s credit evaluation of the borrower. Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. Since many of the commitments may expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. The Bank evaluates each customer’s creditworthiness on a case-by-case basis. Standby letters of credit are conditional commitments issued by the Bank to guarantee the performance of a customer to a third party. Those guarantees are primarily issued to support public and private borrowing arrangements. The credit risk involved in issuing letters of credit is essentially the same as that involved in extending loan facilities to customers. The table below summarizes our off-balance sheet financial instruments whose contract amounts represented credit risk (in thousands): September 30, 2018 December 31, 2017 Commitments to extend credit $ 7,510,397 $ 6,957,847 Standby letters of credit 235,471 230,958 At September 30, 2018 and December 31, 2017 , we had $10.3 million and $9.1 million , respectively, in allowance for off-balance sheet credit losses related to these off-balance sheet commitments recorded in other liabilities in the consolidated balance sheets.

REGULATORY MATTERS

REGULATORY MATTERS	9 Months Ended
	Sep. 30, 2017
Regulatory Capital Requirements [Abstract]
REGULATORY MATTERS	REGULATORY MATTERS The Company and the Bank are subject to various regulatory capital requirements administered by the federal banking agencies. Failure to meet minimum capital requirements can initiate certain mandatory (and possibly additional discretionary) actions by regulators that, if undertaken, could have a direct material adverse effect on the Company’s and the Bank’s financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, the Company and the Bank must meet specific capital guidelines that involve quantitative measures of the Company’s and the Bank’s assets, liabilities, and certain off-balance sheet items as calculated under regulatory accounting practices. The Company’s and the Bank’s capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weightings and other factors. The Basel III regulatory capital framework (the "Basel III Capital Rules") adopted by U.S. federal regulatory authorities, among other things, (i) establishes the capital measure called "Common Equity Tier 1" ("CET1"), (ii) specifies that Tier 1 capital consist of CET1 and "Additional Tier 1 Capital" instruments meeting stated requirements, (iii) requires that most deductions/adjustments to regulatory capital measures be made to CET1 and not to other components of capital and (iv) defines the scope of the deductions/adjustments to the capital measures. The Basel III Capital Rules became effective for us on January 1, 2015 with certain transition provisions fully phasing in over a period ending on January 1, 2019. Additionally, the Basel III Capital Rules require that we maintain a capital conservation buffer with respect to each of CET1, Tier 1 and total capital to risk-weighted assets, which provides for capital levels that exceed the minimum risk-based capital adequacy requirements. The capital conservation buffer is subject to a three year phase-in period that began on January 1, 2016 and will be fully phased in on January 1, 2019 at 2.5%. The required phase-in capital conservation buffer during 2018 is 1.875% and was 1.25% during 2017 . A financial institution with a conservation buffer of less than the required amount is subject to limitations on capital distributions, including dividend payments and stock repurchases, and certain discretionary bonus payments to executive officers. Quantitative measures established by these regulations to ensure capital adequacy require the Company and the Bank to maintain minimum amounts and ratios of CET1, Tier 1 and total capital to risk-weighted assets, and of Tier 1 capital to average assets, each as defined in the regulations. Management believes, as of September 30, 2018 , that the Company and the Bank met all capital adequacy requirements to which they are subject. Financial institutions are categorized as well capitalized or adequately capitalized, based on minimum total risk-based, Tier 1 risk-based, CET1 and Tier 1 leverage ratios. As shown in the table below, the Company’s capital ratios exceeded the regulatory definition of adequately capitalized as of September 30, 2018 and December 31, 2017 . Based upon the information in its most recently filed call report, the Bank met the capital ratios necessary to be well capitalized. The regulatory authorities can apply changes in classification of assets and such changes may retroactively subject the Company to changes in capital ratios. Any such changes could result in reducing one or more capital ratios below well-capitalized status. In addition, a change may result in imposition of additional assessments by the FDIC or could result in regulatory actions that could have a material adverse effect on our financial condition and results of operations. Because our Bank had less than $15.0 billion in total consolidated assets as of December 31, 2009, we are allowed to continue to classify our trust preferred securities, all of which were issued prior to May 19, 2010, as Tier 1 capital. The table below summarizes our actual and required capital ratios under the Basel III Capital Rules: Actual Minimum Capital Required - Basel III Phase-In Schedule Minimum capital Required - Basel III Fully Phased-In Required to be Considered Well Capitalized Capital Amount Ratio Capital Amount Ratio Capital Amount Ratio Capital Amount Ratio As of September 30, 2018: CET1 Company $ 2,258,596 8.64 % $ 1,667,255 6.38 % $ 1,830,712 7.00 % N/A N/A Bank 2,266,454 8.67 % 1,665,912 6.38 % 1,829,237 7.00 % 1,698,577 6.50 % Total capital (to risk-weighted assets) Company 2,999,161 11.47 % 2,582,611 9.88 % 2,746,067 10.50 % N/A N/A Bank 2,848,430 10.90 % 2,580,531 9.88 % 2,743,856 10.50 % 2,613,196 10.00 % Tier 1 capital (to risk-weighted assets) Company 2,516,895 9.62 % 2,059,550 7.88 % 2,223,007 8.50 % N/A N/A Bank 2,424,753 9.28 % 2,057,892 7.88 % 2,221,217 8.50 % 2,090,557 8.00 % Tier 1 capital (to average assets)(1) Company 2,516,895 9.70 % 1,038,268 4.00 % 1,038,268 4.00 % N/A N/A Bank 2,424,753 9.35 % 1,037,796 4.00 % 1,037,796 4.00 % 1,297,245 5.00 % As of December 31, 2017: CET1 Company $ 2,033,830 8.45 % $ 1,384,448 5.75 % $ 1,685,464 7.00 % N/A N/A Bank 1,992,152 8.28 % 1,383,475 5.75 % 1,684,231 7.00 % 1,563,929 6.50 % Total capital (to risk-weighted assets) Company 2,768,153 11.50 % 2,227,221 9.25 % 2,528,196 10.50 % N/A N/A Bank 2,567,961 10.67 % 2,225,591 9.25 % 2,526,347 10.50 % 2,406,044 10.00 % Tier 1 capital (to risk-weighted assets) Company 2,293,016 9.52 % 1,745,659 7.25 % 2,046,635 8.50 % N/A N/A Bank 2,151,338 8.94 % 1,744,382 7.25 % 2,045,138 8.50 % 1,924,835 8.00 % Tier 1 capital (to average assets)(1) Company 2,293,016 9.15 % 1,002,494 4.00 % 1,002,494 4.00 % N/A N/A Bank 2,151,338 8.59 % 1,002,144 4.00 % 1,002,144 4.00 % 1,252,680 5.00 % (1) The Tier 1 capital ratio (to average assets) is not impacted by the Basel III Capital Rules; however, it should be noted that the Federal Reserve Board and the FDIC may require the Company and the Bank, respectively, to maintain a Tier 1 capital ratio (to average assets) above the required minimum. Our mortgage finance loan volumes can increase significantly at month end, causing a meaningful difference between ending balance and average balance for any period. At September 30, 2018 , our total mortgage finance loans were $5.5 billion compared to the average for the three months ended September 30, 2018 of $5.4 billion . As CET1, Tier 1 and total capital ratios are calculated using quarter-end risk-weighted assets and our mortgage finance loans are 100% risk-weighted (excluding MCA mortgage loans held for sale, which receive lower risk weights), the quarter-end fluctuation in these balances can significantly impact our reported ratios. Due to the actual risk profile and liquidity of this asset class, we manage capital allocated to mortgage finance loans based on changing trends in average balances and do not believe that the quarter-end balance is representative of risk characteristics that would justify higher allocations. However, we continue to monitor our capital allocation to confirm that all capital levels remain above well-capitalized levels. Dividends that may be paid by subsidiary banks are routinely restricted by various regulatory authorities. The amount that can be paid in any calendar year without prior approval of the Bank’s regulatory agencies cannot exceed the lesser of the net profits (as defined) for that year plus the net profits for the preceding two calendar years, or retained earnings. The Basel III Capital Rules further limit the amount of dividends that may be paid by our Bank. No dividends were declared or paid on our common stock during the nine months ended September 30, 2018 or 2017 .

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	9 Months Ended
	Sep. 30, 2018
Compensation Related Costs [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION We have long-term incentive plans under which stock-based compensation awards are granted to employees and directors by the board of directors, or its designated committee. Grants are subject to vesting requirements and may include, among other things, nonqualified stock options, stock appreciation rights ("SARs"), restricted stock units ("RSUs"), restricted stock and performance units, or any combination thereof. There are 2,550,000 total shares authorized for grant under the plans. The table below summarizes our stock-based compensation expense for the three and nine months ended September 30, 2018 and 2017 (in thousands): Three months ended September 30, Nine months ended September 30, 2018 2017 2018 2017 Stock-settled awards: SARs $ 19 $ 64 $ 112 $ 210 RSUs 2,261 2,184 6,235 5,491 Restricted stock 12 8 36 16 Cash-settled performance units 2,144 3,811 9,250 9,304 Total $ 4,436 $ 6,067 $ 15,633 $ 15,021 (in thousands) September 30, 2018 Unrecognized compensation expense related to unvested stock-settled awards $ 17,487 Weighted average period over which expense is expected to be recognized, in years 2.8

INCOME TAXES (Notes)

INCOME TAXES (Notes)	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The Tax Cuts and Jobs Act (the "Tax Act") enacted in December 2017 reduced the federal corporate income tax rate from 35% to 21% effective January 1, 2018. As a result of the Tax Act, we re-measured certain deferred tax assets and liabilities based on the rates at which they are expected to reverse in the future, which is generally 21%. However, we are still analyzing certain aspects of the Tax Act and refining our calculations, which could potentially affect the measurement of these balances or potentially give rise to new deferred tax amounts. The provisional amount recorded in 2017 related to the re-measurement of our deferred tax asset was $17.6 million , and no further adjustments were made during the nine months ended September 30, 2018 . The reconciliation of our total effective income tax rate to the U.S. federal statutory tax rate for the nine months ended September 30, 2018 and 2017 is as follows: Nine months ended September 30, 2018 2017 U.S. statutory rate 21 % 35 % State taxes 1 % 1 % Non-deductible expenses 1 % — % Non-taxable income (1 )% (1 )% Other (1 )% (1 )% Effective tax rate 21 % 34 %

FAIR VALUE DISCLOSURES

FAIR VALUE DISCLOSURES	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
FAIR VALUE DISCLOSURES	FAIR VALUE DISCLOSURES We determine the fair market values of our assets and liabilities measured at fair value on a recurring and nonrecurring basis using the fair value hierarchy as prescribed in ASC 820, Fair Value Measurements and Disclosures . The standard describes three levels of inputs that may be used to measure fair value as provided below. Level 1 Quoted prices in active markets for identical assets or liabilities. This category includes the assets and liabilities related to our non-qualified deferred compensation plan where values are based on quoted market prices for identical equity securities in an active market. Level 2 Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 2 assets include agency mortgage-backed debt securities and Community Reinvestment Act funds. This category also includes certain loans held for sale and derivative assets and liabilities where values are obtained from independent pricing services using observable market data. Level 3 Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, discounted cash flow methodologies or similar techniques, as well as instruments for which the determination of fair values requires significant management judgment or estimation. This category includes tax-exempt asset-backed securities for which fair value is determined using a price-based model and certain loans held for sale for which fair values are determined using third party pricing models. This category also includes impaired loans and OREO where collateral values have been based on third party appraisals; however, comparative sales data typically used in appraisals may be unavailable or more subjective in certain markets due to lack of market activity. Assets and liabilities measured at fair value at September 30, 2018 and December 31, 2017 are as follows (in thousands): Fair Value Measurements Using September 30, 2018 Level 1 Level 2 Level 3 Available-for-sale debt securities:(1) Residential mortgage-backed securities $ — $ 7,709 $ — Tax-exempt asset-backed securities — — 93,369 Equity securities(1)(2) 9,461 6,850 — Loans held for sale (3) — 1,630,017 21,913 Loans held for investment(4)(6) — — 19,823 OREO(5)(6) — — 79 Derivative assets(7) — 35,781 — Derivative liabilities(7) — 27,381 — Non-qualified deferred compensation plan liabilities (8) 10,467 — — December 31, 2017 Available-for-sale debt securities:(1) Residential mortgage-backed securities $ — $ 10,945 $ — Equity securities(1)(2) 5,460 7,106 — Loans held for sale(3) — 1,007,695 — Loans held for investment(4)(6) — — 21,216 OREO(5)(6) — — 11,742 Derivative assets(7) — 16,719 — Derivative liabilities(7) — 17,377 — Non-qualified deferred compensation plan liabilities (8) 5,587 — — (1) Securities are measured at fair value on a recurring basis, generally monthly, except for tax-exempt asset-backed securities which are measured quarterly. (2) Equity securities consist of Community Reinvestment Act funds and investments related to our non-qualified deferred compensation plan. (3) Loans held for sale, excluding SBA loans which are carried at lower of cost or market, are measured at fair value on a recurring basis, generally monthly. (4) Includes impaired loans that have been measured for impairment at the fair value of the loan’s collateral. (5) OREO is transferred from loans to OREO at fair value less selling costs. (6) Loans held for investment and OREO are measured on a nonrecurring basis, generally annually or more often as warranted by market and economic conditions. (7) Derivative assets and liabilities are measured at fair value on a recurring basis, generally quarterly. (8) Non-qualified deferred compensation plan liabilities represent the fair value of the obligation to the employee, which corresponds to the fair value of the invested assets, and are measured at fair value on a recurring basis, generally monthly. Level 3 Valuations Financial instruments are considered Level 3 when their values are determined using pricing models, discounted cash flow methodologies or similar techniques and at least one significant model assumption or input is unobservable. Level 3 financial instruments include those for which the determination of fair value requires significant management judgment or estimation. Currently, we measure the fair value of tax-exempt asset-backed securities using a price-based model and certain loans held for sale using third party pricing models on a recurring basis, and measure certain collateral dependent impaired loans and OREO on a nonrecurring basis as described below. Level 3 Fair Value Rollforward The following table presents a reconciliation for the three and nine months ended September 30, 2018 of the level 3 fair value category measured at fair value on a recurring basis using Level 3 inputs (in thousands): Net Realized/Unrealized Gains (Losses) Balance at Beginning of Period Purchases / Additions Sales / Reductions Realized Unrealized Balance at End of Period Three months ended September 30, 2018 Tax-exempt asset-backed securities(1) $ — $ 95,521 $ — $ — $ (2,152 ) $ 93,369 Loans held for sale(2) $ 27,929 $ 901 $ (6,948 ) $ (134 ) $ 165 $ 21,913 Nine months ended September 30, 2018 Tax-exempt asset-backed securities $ — $ 95,521 $ — $ — $ (2,152 ) $ 93,369 Loans held for sale $ — $ 38,430 $ (14,936 ) $ (66 ) $ (1,515 ) $ 21,913 (1) Changes in fair value of available-for-sale debt securities are recorded in accumulated other comprehensive income. (2) Recorded in other non-interest income. Tax-exempt asset-backed securities The fair value of tax-exempt asset-backed securities is based on a price-based model, which utilizes Level 3, or unobservable, inputs. The fair value of these securities is generally based upon quoted prices of the underlying assets, which are used to calculate a weighted-average value. Other considerations include credit deterioration of underlying bonds, the probability of the sponsor exercising their call option and liquidity risks due to the instrument not being actively traded. At September 30, 2018 , the fair value of these securities was calculated using a weighted-average price of 97.7% . Loans held for sale The fair value of loans held for sale using Level 3 inputs include loans that cannot be sold through normal sale channels and thus require significant management judgment or estimation when determining the fair value. The fair value of such loans is generally based upon quoted prices of comparable loans with a liquidity discount applied. At September 30, 2018 , the fair value of these loans was calculated using a weighted-average discounted price of 93.5% . Loans held for investment At September 30, 2018 and December 31, 2017 , certain impaired loans held for investment were reported at fair value through a specific allocation of the allowance for loan losses based upon the fair value of the underlying collateral. The $19.8 million fair value of loans held for investment at September 30, 2018 reported above includes impaired loans held for investment with a carrying value of $28.0 million that were reduced by specific allowance allocations totaling $8.2 million based on collateral valuations utilizing Level 3 inputs. The $21.2 million fair value of loans held for investment at December 31, 2017 reported above includes impaired loans with a carrying value of $32.2 million that were reduced by specific valuation allowance allocations totaling $11.0 million based on collateral valuations utilizing Level 3 inputs. Fair values were based on third party appraisals, which are Level 3 inputs. OREO Certain foreclosed assets, upon initial recognition, are recorded at fair value less estimated selling costs. At September 30, 2018 and December 31, 2017 , OREO had a carrying value of $79,000 and $11.7 million , respectively, with no valuation allowance at September 30, 2018 or December 31, 2017 . The fair value of OREO was computed based on third party appraisals, which are Level 3 inputs. Fair Value of Financial Instruments GAAP requires disclosure of fair value information about financial instruments, whether or not recognized on the balance sheet, for which it is practical to estimate that value. In cases where quoted market prices are not available, fair values are based on estimates using present value or other valuation techniques. Those techniques are significantly affected by the assumptions used, including the discount rate and estimates of future cash flows. This disclosure does not and is not intended to represent the fair value of the Company. A summary of the carrying amounts and estimated fair values of financial instruments is as follows (in thousands): September 30, 2018 December 31, 2017 Carrying Amount Estimated Fair Value Carrying Estimated Financial assets: Level 1 inputs: Cash and cash equivalents $ 2,785,051 $ 2,785,051 $ 2,905,591 $ 2,905,591 Investment securities 9,461 9,461 5,460 5,460 Level 2 inputs: Investment securities 14,559 14,559 18,051 18,051 Loans held for sale 1,630,017 1,630,017 1,011,004 1,011,004 Derivative assets 35,781 35,781 16,719 16,719 Level 3 inputs: Investment securities 93,369 93,369 — — Loans held for sale 21,913 21,913 — — Loans held for investment, net 21,857,019 21,843,389 20,489,757 20,480,802 Financial liabilities: Level 2 inputs: Federal funds purchased 475,842 475,842 359,338 359,338 Customer repurchase agreements 10,976 10,976 5,702 5,702 Other borrowings 3,200,000 3,200,000 2,800,000 2,800,000 Subordinated notes 281,677 282,247 281,406 285,485 Derivative liabilities 27,381 27,381 17,377 17,377 Level 3 inputs: Deposits 20,385,637 20,386,435 19,123,180 19,124,121 Trust preferred subordinated debentures 113,406 113,406 113,406 113,406 The following methods and assumptions were used by the Company in estimating its fair value disclosures for financial instruments: Investment Securities Within the investment securities portfolio, we hold equity securities related to our non-qualified deferred compensation plan that are valued using quoted market prices for identical equity securities in an active market, and are classified as Level 1 assets in the fair value hierarchy. The fair value of the remaining equity securities and residential mortgage-backed securities in our investment portfolio are based on prices obtained from independent pricing services that are based on quoted market prices for the same or similar securities, and are characterized as Level 2 assets in the fair value hierarchy. We have obtained documentation from our primary pricing service regarding their processes and controls applicable to pricing investment securities, and on a quarterly basis we independently verify the prices that we receive from the service provider using two additional independent pricing sources. We also hold tax-exempt asset-backed securities that are valued using a price-based model, which utilizes Level 3 inputs, and are classified as Level 3 assets in the fair value hierarchy. Loans Held for Sale Fair value for loans held for sale is derived from quoted market prices for similar loans, in which case they are characterized as Level 2 assets in the fair value hierarchy, or is derived from third party pricing models, in which case they are characterized as Level 3 assets in the fair value hierarchy. Derivatives The estimated fair value of interest rate swaps and caps is obtained from independent pricing services based on quoted market prices for similar derivative contracts and these financial instruments are characterized as Level 2 assets and liabilities in the fair value hierarchy. On a quarterly basis, we independently verify the fair value using an additional independent pricing source. Any significant differences are investigated and resolved. Foreign currency forward contracts are valued based upon quoted market prices obtained from independent pricing services for similar derivative contracts. As such, these financial instruments are characterized as Level 2 assets and liabilities in the fair value hierarchy. The derivative instruments related to the loans held for sale portfolio include loan purchase commitments and forward sales commitments. Loan purchase commitments are valued based upon the fair value of the underlying mortgage loans to be purchased, which is based on observable market data for similar loans. Forward sales commitments are valued based upon quoted market prices from brokers. As such, these loan purchase commitments and forward sales commitments are characterized as Level 2 assets or liabilities in the fair value hierarchy.

DERIVATIVE FINANCIAL INSTRUMENT

DERIVATIVE FINANCIAL INSTRUMENTS	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE FINANCIAL INSTRUMENTS	DERIVATIVE FINANCIAL INSTRUMENTS The fair value of derivative positions outstanding is included in accrued interest receivable and other assets and other liabilities in the accompanying consolidated balance sheets on a net basis when a right of offset exists, based on transactions with a single counterparty that are subject to a legally enforceable master netting agreement. We enter into interest rate derivative positions that are not designated as hedging instruments. These derivative positions relate to transactions in which we enter into an interest rate swap, cap and/or floor with a customer while at the same time entering into an offsetting interest rate swap, cap and/or floor with another financial institution. In connection with each swap transaction, we agree to pay interest to the customer on a notional amount at a variable interest rate and receive interest from the customer on a similar notional amount at a fixed interest rate. At the same time, we agree to pay another financial institution the same fixed interest rate on the same notional amount and receive the same variable interest rate on the same notional amount. The transaction allows our customer to effectively convert a variable rate loan to a fixed rate. Because we act as an intermediary for our customer, changes in the fair value of the underlying derivative contracts substantially offset each other and do not have a material impact on our results of operations. We also enter into foreign currency forward contracts that are not designated as hedging instruments. These derivative instruments relate to transactions in which we enter into a contract with a customer to buy or sell a foreign currency at a future date for a specified price while at the same time entering into an offsetting contract with a financial institution to buy or sell the same currency at the same future date for a specified price. These transactions allow our customers to manage their exposure to foreign currency exchange rate fluctuations. Because we act as an intermediary for our customer, changes in the fair value of the underlying derivative instruments substantially offset each other and do not have a material impact on our results of operations. We also enter into loan purchase commitment contracts with mortgage originators to purchase residential mortgage loans at a future date, as well as forward sales commitment contracts to sell residential mortgage loans at a future date as part of our MCA program. The objective of these transactions is to mitigate our exposure to interest rate risk associated with the purchase of mortgage loans held for sale. Any changes in fair value are recorded in other non-interest expense in the consolidated statements of income and other comprehensive income. The notional amounts and estimated fair values of interest rate derivative positions outstanding at September 30, 2018 and December 31, 2017 are presented in the following tables (in thousands): September 30, 2018 December 31, 2017 Estimated Fair Value Estimated Fair Value Notional Amount Asset Derivative Liability Derivative Notional Amount Asset Derivative Liability Derivative Non-hedging interest rate derivatives: Financial institution counterparties: Commercial loan/lease interest rate swaps $ 1,593,483 $ 21,796 $ 4,691 $ 1,393,764 $ 4,736 $ 15,482 Commercial loan/lease interest rate caps 567,490 2,525 17 242,700 421 7 Foreign currency forward contracts 50,975 2,441 — 2,466 4 69 Customer counterparties: Commercial loan/lease interest rate swaps 1,593,483 4,691 21,796 1,393,764 15,482 4,736 Commercial loan/lease interest rate caps 567,490 17 2,525 242,700 7 421 Foreign currency forward contracts 50,975 — 2,441 2,466 69 4 Economic hedging interest rate derivatives: Loan purchase commitments 308,933 1,104 81 253,815 635 190 Forward sales commitments 1,851,500 7,441 64 1,086,224 — 1,103 Gross derivatives 40,015 31,615 21,354 22,012 Offsetting derivative assets/liabilities (4,234 ) (4,234 ) (4,635 ) (4,635 ) Net derivatives included in the consolidated balance sheets $ 35,781 $ 27,381 $ 16,719 $ 17,377 The weighted average received and paid interest rates for interest rate swaps outstanding at September 30, 2018 and December 31, 2017 were as follows: September 30, 2018 December 31, 2017 Received Paid Received Paid Non-hedging interest rate swaps 3.92 % 4.17 % 3.59 % 4.34 % The weighted average strike rate for outstanding interest rate caps was 3.17% at September 30, 2018 and 2.40% at December 31, 2017 . Our credit exposure on derivative instruments is limited to the net favorable value and interest payments by each counterparty. In some cases collateral may be required from the counterparties involved if the net value of the derivative instruments exceeds a nominal amount . Our credit exposure associated with these instruments, net of any collateral pledged, was approximately $20.9 million at September 30, 2018 and approximately $16.7 million at December 31, 2017 . Collateral levels are monitored and adjusted on a regular basis for changes in interest rate swap and cap values, as well as for changes in the value of forward sales commitments. At September 30, 2018 , we had pledged to counterparties $740,000 in cash collateral for these derivatives, all of which was included in interest-bearing deposits in other banks, and counterparties had pledged to us $17.9 million in cash collateral included in interest-bearing deposits. At December 31, 2017 , we had pledged to counterparties $15.2 million in cash collateral for these derivatives, of which $14.0 million was included in interest-bearing deposits in other banks and $1.2 million was included in accrued interest receivable and other assets. We also enter into credit risk participation agreements with financial institution counterparties for interest rate swaps related to loans in which we are either a participant or a lead bank. The risk participation agreements entered into by us as a participant bank provide credit protection to the financial institution counterparty should the borrower fail to perform on its interest rate derivative contract with that financial institution. We are party to 14 risk participation agreements where we are a participant bank having a notional amount of $133.1 million at September 30, 2018 , compared to 15 risk participation agreements having a notional amount of $157.1 million at December 31, 2017 . The maximum estimated exposure to these agreements, assuming 100% default by all obligors, was approximately $120,000 at September 30, 2018 and $221,000 at December 31, 2017 . The fair value of these exposures was insignificant to the consolidated financial statements at both September 30, 2018 and December 31, 2017 . Risk participation agreements entered into by us as the lead bank provide credit protection to us should the borrower fail to perform on its interest rate derivative contract with us. We are party to 10 risk participation agreements where we are the lead bank having a notional amount of $122.4 million at September 30, 2018 , compared to 10 agreements having a notional amount of $86.3 million at December 31, 2017 .

NEW ACCOUNTING PRONOUNCEMENTS

NEW ACCOUNTING PRONOUNCEMENTS	9 Months Ended
	Sep. 30, 2018
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
NEW ACCOUNTING PRONOUNCEMENTS	NEW ACCOUNTING PRONOUNCEMENTS ASU 2018-15 "Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40 - Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract" ("ASU 2018-15") aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). ASU 2018-15 will be effective for us on January 1, 2020 and is not expected to have an impact on our consolidated financial statements as we currently apply this guidance in practice. ASU 2018-13 "Fair Value Measurement (Topic 820) - Changes to the Disclosure Requirements for Fair Value Measurement" ("ASU 2018-13") removes the requirement to disclose the amount of and reasons for transfers between Level 1 and Level 2 fair value measurement methodologies, the policy for timing of transfers between levels and the valuation processes for Level 3 fair value measurements. It also adds a requirement to disclose changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period and the range and weighted average of significant unobservable inputs used to develop Level 3 measurements. For certain unobservable inputs, entities may disclose other quantitative information in lieu of the weighted average if the other quantitative information would be a more reasonable and rational method to reflect the distribution of unobservable inputs used to develop Level 3 fair value measurements. ASU 2018-13 will be effective for us on January 1, 2020. We are evaluating the impact adoption will have on our disclosures. ASU 2016-13 "Financial Instruments - Credit Losses (Topic 326)" ("ASU 2016-13") requires an entity to utilize a new impairment model known as the current expected credit loss ("CECL") model to estimate its lifetime "expected credit loss" and record an allowance that, when deducted from the amortized cost basis of the financial asset, presents the net amount expected to be collected on the financial asset. The CECL model is expected to result in more timely recognition of credit losses. ASU 2016-13 also requires new disclosures for financial assets measured at amortized cost, loans and available-for-sale debt securities. Entities will apply the standard's provisions as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is adopted. ASU 2016-13 will be effective for us on January 1, 2020. We are evaluating the impact adoption of ASU 2016-13 will have on our consolidated financial statements and disclosures. While we are currently unable to reasonably estimate the impact of adopting ASU 2016-13, we expect that the impact of adoption could be significantly influenced by the composition, characteristics and quality of our loan portfolio as well as the prevailing economic conditions and forecasts as of the adoption date. As part of our evaluation process, we have established a steering committee and working group that includes individuals from various functional areas to assess processes, portfolio segmentation, systems requirements and needed resources to implement this new accounting standard. ASU 2016-02 " Leases (Topic 842) " ("ASU 2016-02") requires that lessees and lessors recognize lease assets and lease liabilities on the balance sheet and disclose key information about leasing arrangements. ASU 2016-02 will be effective for us on January 1, 2019. ASU 2016-02 provides for a modified retrospective transition approach requiring lessees to recognize and measure leases on the balance sheet at the beginning of either the earliest period presented or as of the beginning of the period of adoption with the option to elect certain practical expedients. We are electing to apply ASU 2016-02 as of the beginning of the period of adoption (January 1, 2019) and will not restate comparative periods. We also expect to elect certain optional practical expedients. We have implemented a third party software solution to assist with the accounting under the new standard. Our operating leases relate primarily to office space and bank branches. Based on our current lease portfolio, we anticipate recognizing a lease liability and related right-of-use asset on our balance sheet, with an immaterial impact on our income statement compared to the current lease accounting model. However, the ultimate impact of the standard will depend on the company’s lease portfolio as of the adoption date.

Summary of Significant Accounti

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Nature of Business	Organization and Nature of Business Texas Capital Bancshares, Inc. (the “Company”), a Delaware corporation, was incorporated in November 1996 and commenced banking operations in December 1998. The consolidated financial statements of the Company include the accounts of Texas Capital Bancshares, Inc. and its wholly owned subsidiary, Texas Capital Bank, National Association (the “Bank”). We serve the needs of commercial businesses and successful professionals and entrepreneurs located in Texas as well as operate several lines of business serving a regional and national clientèle of commercial borrowers. We are primarily a secured lender with a majority of our loans being made to businesses headquartered or with operations in Texas. At the same time, our national lines of business continue to provide specialized lending products,as well as treasury services, deposit products and other complementary banking services, to businesses throughout the United States.
Basis of Presentation	Basis of Presentation Our accounting and reporting policies conform to accounting principles generally accepted in the United States (“GAAP”) and to generally accepted practices within the banking industry. Certain prior period balances have been reclassified to conform to the current period presentation. The consolidated interim financial statements are unaudited and certain information and footnote disclosures presented in accordance with GAAP have been condensed or omitted. In the opinion of management, the interim financial statements include all normal and recurring adjustments and the disclosures made are adequate to make the interim financial information not misleading. The consolidated financial statements have been prepared in accordance with GAAP for interim financial information and the instructions to Form 10-Q adopted by the Securities and Exchange Commission (“SEC”). Accordingly, the financial statements do not include all of the information and footnotes required by GAAP for complete financial statements and should be read in conjunction with our consolidated financial statements, and notes thereto, for the year ended December 31, 2017 , included in our Annual Report on Form 10-K filed with the SEC on February 14, 2018 (the “ 2017 Form 10-K”). Operating results for the interim periods disclosed herein are not necessarily indicative of the results that may be expected for a full year or any future period.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates. The allowance for loan losses, the fair value of stock-based compensation awards, the fair value of mortgage servicing rights ("MSRs") and the status of contingencies are particularly susceptible to significant change.

EARNINGS PER COMMON SHARE (Tabl

EARNINGS PER COMMON SHARE (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Schedule of computation of basic and diluted earnings per share	The following table presents the computation of basic and diluted earnings per share (in thousands except share data): Three months ended Nine months ended 2018 2017 2018 2017 Numerator: Net income $ 85,552 $ 58,684 $ 228,933 $ 152,321 Preferred stock dividends 2,438 2,438 7,313 7,313 Net income available to common stockholders 83,114 56,246 $ 221,620 145,008 Denominator: Denominator for basic earnings per share—weighted average shares 50,163,433 49,607,028 49,853,515 49,573,456 Effect of employee stock-based awards (1) 207,391 214,468 240,376 235,011 Effect of warrants to purchase common stock 10,525 429,370 115,537 431,551 Denominator for dilutive earnings per share—adjusted weighted average shares and assumed conversions 50,381,349 50,250,866 50,209,428 50,240,018 Basic earnings per common share $ 1.66 $ 1.13 $ 4.45 $ 2.93 Diluted earnings per common share $ 1.65 $ 1.12 $ 4.41 $ 2.89 (1) SARs and RSUs outstanding of 4,000 at September 30, 2018 and 6,200 at September 30, 2017 have not been included in diluted earnings per share because to do so would have been anti-dilutive for the periods presented.

INVESTMENT SECURITIES (Tables)

INVESTMENT SECURITIES (Tables)	9 Months Ended
	Sep. 30, 2018
Available-for-sale Securities [Abstract]
Schedule of summary of securities	The following is a summary of available-for-sale debt securities (in thousands): September 30, 2018 Amortized Gross Gross Estimated Residential mortgage-backed securities $ 7,299 $ 410 $ — $ 7,709 Tax-exempt asset-backed securities 95,521 — (2,152 ) 93,369 $ 102,820 $ 410 $ (2,152 ) $ 101,078 December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Residential mortgage-backed securities $ 10,297 $ 648 $ — $ 10,945
Schedule of amortized cost and estimated fair value of securities	The amortized cost and estimated fair value of available-for-sale debt securities are presented below by contractual maturity (in thousands, except percentage data): September 30, 2018 Less Than After One After Five After Ten Total Residential mortgage-backed securities: (1) Amortized cost 12 1,727 — 5,560 7,299 Estimated fair value 13 1,846 — 5,850 7,709 Weighted average yield (3) 6.23 % 5.55 % — % 3.79 % 4.21 % Tax-exempt asset-backed securities:(1) Amortized cost — — — 95,521 95,521 Estimated fair value — — — 93,369 93,369 Weighted average yield(2)(3) — % — % — % 4.25 % 4.25 % Total available-for-sale debt securities: Amortized cost $ 102,820 Estimated fair value $ 101,078 December 31, 2017 Less Than After One After Five After Ten Total Residential mortgage-backed securities:(1) Amortized cost $ 409 $ 819 $ 1,502 $ 7,567 $ 10,297 Estimated fair value 418 916 1,636 7,975 10,945 Weighted average yield(3) 4.59 % 6.02 % 5.32 % 3.45 % 3.97 % (1) Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without prepayment penalties. (2) Yields have been adjusted to a tax equivalent basis assuming a 21% federal tax rate. (3) Yields are calculated based on amortized cost.
Summary of unrealized and realized gains and losses recognized on equity securities	The following is a summary of unrealized and realized gains and losses recognized in net income on equity securities during the three and nine months ended September 30, 2018 (in thousands): Three months ended Nine months ended September 30, 2018 September 30, 2018 Net gains and (losses) recognized during the period on equity securities $ 253 $ 149 Less: Net gains and (losses) recognized during the period on equity securities sold during the period 18 180 Unrealized gains and (losses) recognized during the reporting period on equity securities still held at the reporting date $ 235 $ (31 )
Schedule of debt securities, available for sale	The following table discloses as of September 30, 2018 our available-for-sale debt securities that have been in a continuous unrealized loss position for less than 12 months and those that have been in a continuous unrealized loss position for 12 or more months (in thousands): September 30, 2018 Less Than 12 Months 12 Months or Longer Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Tax-exempt asset-backed securities $ 93,369 $ (2,152 ) $ — $ — $ 93,369 $ (2,152 )

LOANS AND ALLOWANCE FOR LOAN _2

LOANS AND ALLOWANCE FOR LOAN LOSSES (Tables)	9 Months Ended
	Sep. 30, 2018
Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract]
Schedule of loans held for investments	At September 30, 2018 and December 31, 2017 , loans held for investment were as follows (in thousands): September 30, December 31, Commercial $ 10,116,945 $ 9,189,811 Mortgage finance 5,477,787 5,308,160 Construction 2,263,463 2,166,208 Real estate 3,924,682 3,794,577 Consumer 51,692 48,684 Leases 319,411 264,903 Gross loans held for investment 22,153,980 20,772,343 Deferred income (net of direct origination costs) (106,655 ) (97,931 ) Allowance for loan losses (190,306 ) (184,655 ) Total loans held for investment, net $ 21,857,019 $ 20,489,757
Schedule of the credit risk profile of loan portfolio by internally assigned grades and non-accrual status	The following tables summarize the credit risk profile of our loan portfolio by internally assigned grades and non-accrual status as of September 30, 2018 and December 31, 2017 (in thousands): September 30, 2018 Commercial Mortgage Finance Construction Real Estate Consumer Leases Total Grade: Pass $ 9,851,525 $ 5,477,787 $ 2,250,650 $ 3,845,393 $ 50,064 $ 318,969 $ 21,794,388 Special mention 96,168 — 12,813 44,486 — 442 153,909 Substandard-accruing 64,295 — — 32,288 1,568 — 98,151 Non-accrual 104,957 — — 2,515 60 — 107,532 Total loans held for investment $ 10,116,945 $ 5,477,787 $ 2,263,463 $ 3,924,682 $ 51,692 $ 319,411 $ 22,153,980 December 31, 2017 Commercial Mortgage Finance Construction Real Estate Consumer Leases Total Grade: Pass $ 8,967,471 $ 5,308,160 $ 2,152,654 $ 3,706,541 $ 48,591 $ 249,865 $ 20,433,282 Special mention 19,958 — 13,554 53,652 — 495 87,659 Substandard-accruing 102,651 — — 32,671 93 14,543 149,958 Non-accrual 99,731 — — 1,713 — — 101,444 Total loans held for investment $ 9,189,811 $ 5,308,160 $ 2,166,208 $ 3,794,577 $ 48,684 $ 264,903 $ 20,772,343
Schedule of activity in the reserve for loan losses by portfolio segment	The following table details activity in the allowance for loan losses by portfolio segment for the 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. September 30, 2018 (in thousands) Commercial Mortgage Finance Construction Real Estate Consumer Leases Additional Qualitative Reserve Total Beginning balance $ 118,806 $ — $ 19,273 $ 34,287 $ 357 $ 3,542 $ 8,390 $ 184,655 Provision for loan losses 55,808 — 331 (1,635 ) 757 (1,425 ) (3,048 ) 50,788 Charge-offs 45,273 — — — 767 319 — 46,359 Recoveries 1,069 — — 43 78 32 — 1,222 Net charge-offs (recoveries) 44,204 — — (43 ) 689 287 — 45,137 Ending balance $ 130,410 $ — $ 19,604 $ 32,695 $ 425 $ 1,830 $ 5,342 $ 190,306 Period end amount allocated to: Loans individually evaluated for impairment $ 30,855 $ — $ — $ 70 $ 10 $ — $ — $ 30,935 Loans collectively evaluated for impairment 99,555 — 19,604 32,625 415 1,830 5,342 159,371 Ending balance $ 130,410 $ — $ 19,604 $ 32,695 $ 425 $ 1,830 $ 5,342 $ 190,306 September 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 21,388 — 4,431 12,948 221 2,774 1,899 43,661 Charge-offs 32,146 — 59 290 180 — — 32,675 Recoveries 3,574 — 104 74 56 9 — 3,817 Net charge-offs (recoveries) 28,572 — (45 ) 216 124 (9 ) — 28,858 Ending balance $ 121,584 $ — $ 17,620 $ 31,881 $ 338 $ 3,907 $ 7,599 $ 182,929 Period end amount allocated to: Loans individually evaluated for impairment $ 24,410 $ — $ — $ 26 $ — $ — $ — $ 24,436 Loans collectively evaluated for impairment 97,174 — 17,620 31,855 338 3,907 7,599 158,493 Ending balance $ 121,584 $ — $ 17,620 $ 31,881 $ 338 $ 3,907 $ 7,599 $ 182,929
Schedule of allowance for credit losses related to unfunded commitments	The table below presents the activity in the allowance for off-balance sheet credit losses related to unfunded commitments for the three and nine months ended September 30, 2018 and 2017 (in thousands). This allowance is recorded in other liabilities in the consolidated balance sheet. Three months ended September 30, Nine months ended September 30, 2018 2017 2018 2017 Beginning balance $ 10,458 $ 9,205 $ 9,071 $ 11,422 Provision for off-balance sheet credit losses (175 ) 556 1,212 (1,661 ) Ending balance $ 10,283 $ 9,761 $ 10,283 $ 9,761
Schedule of recorded investment in loans related to each balance in the allowance for loan losses	Our recorded investment in loans as of September 30, 2018 , December 31, 2017 and September 30, 2017 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): September 30, 2018 Commercial Mortgage Finance Construction Real Estate Consumer Leases Total Loans individually evaluated for impairment $ 105,522 $ — $ — $ 9,057 $ 60 $ — $ 114,639 Loans collectively evaluated for impairment 10,011,423 5,477,787 2,263,463 3,915,625 51,632 319,411 22,039,341 Total $ 10,116,945 $ 5,477,787 $ 2,263,463 $ 3,924,682 $ 51,692 $ 319,411 $ 22,153,980 December 31, 2017 Commercial Mortgage Finance Construction Real Estate Consumer Leases Total Loans individually evaluated for impairment $ 100,676 $ — $ — $ 2,008 $ — $ — $ 102,684 Loans collectively evaluated for impairment 9,089,135 5,308,160 2,166,208 3,792,569 48,684 264,903 20,669,659 Total $ 9,189,811 $ 5,308,160 $ 2,166,208 $ 3,794,577 $ 48,684 $ 264,903 $ 20,772,343 September 30, 2017 Commercial Mortgage Finance Construction Real Estate Consumer Leases Total Loans individually evaluated for impairment $ 117,426 $ — $ — $ 2,117 $ — $ — $ 119,543 Loans collectively evaluated for impairment 8,693,399 5,642,285 2,099,355 3,681,447 70,436 259,720 20,446,642 Total $ 8,810,825 $ 5,642,285 $ 2,099,355 $ 3,683,564 $ 70,436 $ 259,720 $ 20,566,185
Schedule of impaired loans, by portfolio class	The following tables detail our impaired loans, by portfolio class, as of September 30, 2018 and December 31, 2017 (in thousands): September 30, 2018 Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized With no related allowance recorded: Commercial Business loans $ 14,669 $ 21,428 $ — $ 16,045 $ 133 Energy 12,777 13,953 — 18,653 — Construction Market risk — — — — — Real estate Market risk — — — — — Commercial 7,557 7,557 — 1,787 — Secured by 1-4 family 1,263 1,263 — 561 — Consumer — — — — — Leases — — — — — Total impaired loans with no allowance recorded $ 36,266 $ 44,201 $ — $ 37,046 $ 133 With an allowance recorded: Commercial Business loans $ 59,618 $ 78,304 $ 24,180 $ 39,880 $ — Energy 18,458 19,718 6,675 27,312 — Construction Market risk — — — — — Real estate Market risk — — — 66 — Commercial — — — 111 — Secured by 1-4 family 237 237 70 171 — Consumer 60 60 10 53 — Leases — — — 367 — Total impaired loans with an allowance recorded $ 78,373 $ 98,319 $ 30,935 $ 67,960 $ — Combined: Commercial Business loans $ 74,287 $ 99,732 $ 24,180 $ 55,925 $ 133 Energy 31,235 33,671 6,675 45,965 — Construction Market risk — — — — — Real estate Market risk — — — 66 — Commercial 7,557 7,557 — 1,898 — Secured by 1-4 family 1,500 1,500 70 732 — Consumer 60 60 10 53 — Leases — — — 367 — Total impaired loans $ 114,639 $ 142,520 $ 30,935 $ 105,006 $ 133 December 31, 2017 Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized With no related allowance recorded: Commercial Business loans $ 16,835 $ 18,257 $ — $ 22,964 $ — Energy 21,426 22,602 — 36,579 — Construction Market risk — — — — — Real estate Market risk — — — — — Commercial 1,096 1,096 — 2,166 — Secured by 1-4 family — — — — — Consumer — — — — — Leases — — — — — Total impaired loans with no allowance recorded $ 39,357 $ 41,955 $ — $ 61,709 $ — With an allowance recorded: Commercial Business loans $ 18,645 $ 19,020 $ 2,544 $ 16,960 $ — Energy 43,770 55,875 21,772 50,867 6 Construction Market risk — — — 27 — Real estate Market risk 295 295 6 485 — Commercial 499 499 75 166 — Secured by 1-4 family 118 118 20 516 — Consumer — — — 33 — Leases — — — 14 — Total impaired loans with an allowance recorded $ 63,327 $ 75,807 $ 24,417 $ 69,068 $ 6 Combined: Commercial Business loans $ 35,480 $ 37,277 $ 2,544 $ 39,924 $ — Energy 65,196 78,477 21,772 87,446 6 Construction Market risk — — — 27 — Real estate Market risk 295 295 6 485 — Commercial 1,595 1,595 75 2,332 — Secured by 1-4 family 118 118 20 516 — Consumer — — — 33 — Leases — — — 14 — Total impaired loans $ 102,684 $ 117,762 $ 24,417 $ 130,777 $ 6
Schedule of an age analysis of accruing past due loans	The table below provides an age analysis of our loans held for investment as of September 30, 2018 (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 $ 51,154 $ 4,304 $ 9,882 $ 65,340 $ 73,722 $ 8,488,962 $ 8,628,024 Energy 13,000 2,281 — 15,281 31,235 1,442,405 1,488,921 Mortgage finance loans — — — — — 5,477,787 5,477,787 Construction Market risk — — — — — 2,182,653 2,182,653 Commercial — — — — — 53,116 53,116 Secured by 1-4 family — — — — — 27,694 27,694 Real estate Market risk 3,471 — 1,413 4,884 — 2,759,177 2,764,061 Commercial 4,192 — — 4,192 1,015 814,646 819,853 Secured by 1-4 family 1,538 85 — 1,623 1,500 337,645 340,768 Consumer — — — — 60 51,632 51,692 Leases 92 — — 92 — 319,319 319,411 Total loans held for investment $ 73,447 $ 6,670 $ 11,295 $ 91,412 $ 107,532 $ 21,955,036 $ 22,153,980 (1) Loans past due 90 days and still accruing includes premium finance loans of $8.2 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.
Schedule of loans that have been restructured	The following table provides information on how loans were modified as restructured during the nine months ended September 30, 2018 and 2017 (in thousands): Nine months ended September 30, 2018 2017 Extended maturity $ — $ 721 Adjusted payment schedule 14,914 — Total $ 14,914 $ 721 The following table summarizes the loans that were restructured during the nine months ended September 30, 2018 and 2017 (in thousands): As of and for the nine months ended September 30, 2018 Number of Restructured Loans Balance at Restructure Balance at Period-End Energy loans 5 $ 12,358 $ 12,332 Commercial business loans 2 2,582 2,582 Total new restructured loans 7 $ 14,940 $ 14,914 As of and for the nine months ended September 30, 2017 Number of Restructured Loans Balance at Restructure Balance at Period-End Energy loans 1 $ 1,070 $ — Commercial business loans 1 599 721 Total new restructured loans 2 $ 1,669 $ 721

OREO AND VALUATION ALLOWANCE _2

OREO AND VALUATION ALLOWANCE FOR LOSSES ON OREO (Tables)	9 Months Ended
	Sep. 30, 2018
Real Estate Owned, Disclosure of Detailed Components [Abstract]
Schedule of the activity related to OREO	The table below presents a summary of the activity related to OREO (in thousands): Three months ended September 30, Nine months ended September 30, 2018 2017 2018 2017 Beginning balance $ 9,526 $ 18,689 $ 11,742 $ 18,961 Additions — — — — Sales (11,447 ) (457 ) (11,663 ) (729 ) Valuation allowance for OREO 2,000 (101 ) — (101 ) Ending balance $ 79 $ 18,131 $ 79 $ 18,131

CERTAIN TRANSFERS OF FINANCIA_2

CERTAIN TRANSFERS OF FINANCIAL ASSETS (Tables)	9 Months Ended
	Sep. 30, 2018
Transfers and Servicing [Abstract]
Schedule of Loans Held for Sale	The table below presents the unpaid principal balance of loans held for sale and related fair values at September 30, 2018 and December 31, 2017 (in thousands): September 30, 2018 December 31, 2017 Outstanding balance(1) $ 1,658,630 $ 1,009,271 Fair value(1) 1,651,930 1,007,695 Fair value over/(under) outstanding balance $ (6,700 ) $ (1,576 ) The table below presents a reconciliation of the changes in loans held for sale for the nine months ended September 30, 2018 and 2017 (in thousands): Nine months ended September 30, 2018 2017 Beginning balance $ 1,011,004 $ 968,929 Loans purchased 5,012,188 4,315,065 Payments and loans sold (4,366,138 ) (4,337,919 ) Change in fair value (5,124 ) 9,908 Ending balance $ 1,651,930 $ 955,983
Servicing Asset at Amortized Cost	We generally retain the right to service the loans sold, creating MSRs which are recorded as assets on our balance sheet. A summary of MSR activity for the nine months ended September 30, 2018 and 2017 is as follows (in thousands): Nine months ended September 30, 2018 2017 MSRs: Balance, beginning of year $ 88,150 $ 28,536 Capitalized servicing rights 32,871 54,614 Amortization (7,920 ) (5,304 ) Sales (26,742 ) — Balance, end of period $ 86,359 $ 77,846 Valuation allowance: Balance, beginning of year $ 2,823 $ — Increase (decrease) in valuation allowance (2,823 ) 216 Balance, end of period $ — $ 216 MSRs, net(1) $ 86,359 $ 77,630 MSRs, fair value $ 98,391 $ 78,940 (1) MSRs are reported on the consolidated balance sheets at amortized cost
Schedule of Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities	As of September 30, 2018 and December 31, 2017 , management used the following assumptions to determine the fair value of MSRs: September 30, 2018 December 31, 2017 Average discount rates 9.62 % 9.90 % Expected prepayment speeds 8.31 % 9.99 % Weighted average life, in years 7.9 7.0
Schedule of Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets	A sensitivity analysis of changes in the fair value of our MSR portfolio resulting from certain key assumptions is presented in the following table (in thousands): September 30, 2018 December 31, 2017 50 bp adverse change in prepayment speed $ (11,581 ) $ (11,896 ) 100 bp adverse change in prepayment speed (24,868 ) (28,226 )

FINANCIAL INSTRUMENTS WITH OF_2

FINANCIAL INSTRUMENTS WITH OFF-BALANCE SHEET RISK (Tables)	9 Months Ended
	Sep. 30, 2018
Risks and Uncertainties [Abstract]
Schedule of financial instruments with off-balance sheet risk	The table below summarizes our off-balance sheet financial instruments whose contract amounts represented credit risk (in thousands): September 30, 2018 December 31, 2017 Commitments to extend credit $ 7,510,397 $ 6,957,847 Standby letters of credit 235,471 230,958 At September 30, 2018 and December 31, 2017 , we had $10.3 million and $9.1 million , respectively, in allowance for off-balance sheet credit losses related to these off-balance sheet commitments recorded in other liabilities in the consolidated balance sheets.

REGULATORY MATTERS (Tables)

REGULATORY MATTERS (Tables)	9 Months Ended
	Sep. 30, 2018
Regulatory Capital Requirements [Abstract]
Schedule of capital ratios	The table below summarizes our actual and required capital ratios under the Basel III Capital Rules: Actual Minimum Capital Required - Basel III Phase-In Schedule Minimum capital Required - Basel III Fully Phased-In Required to be Considered Well Capitalized Capital Amount Ratio Capital Amount Ratio Capital Amount Ratio Capital Amount Ratio As of September 30, 2018: CET1 Company $ 2,258,596 8.64 % $ 1,667,255 6.38 % $ 1,830,712 7.00 % N/A N/A Bank 2,266,454 8.67 % 1,665,912 6.38 % 1,829,237 7.00 % 1,698,577 6.50 % Total capital (to risk-weighted assets) Company 2,999,161 11.47 % 2,582,611 9.88 % 2,746,067 10.50 % N/A N/A Bank 2,848,430 10.90 % 2,580,531 9.88 % 2,743,856 10.50 % 2,613,196 10.00 % Tier 1 capital (to risk-weighted assets) Company 2,516,895 9.62 % 2,059,550 7.88 % 2,223,007 8.50 % N/A N/A Bank 2,424,753 9.28 % 2,057,892 7.88 % 2,221,217 8.50 % 2,090,557 8.00 % Tier 1 capital (to average assets)(1) Company 2,516,895 9.70 % 1,038,268 4.00 % 1,038,268 4.00 % N/A N/A Bank 2,424,753 9.35 % 1,037,796 4.00 % 1,037,796 4.00 % 1,297,245 5.00 % As of December 31, 2017: CET1 Company $ 2,033,830 8.45 % $ 1,384,448 5.75 % $ 1,685,464 7.00 % N/A N/A Bank 1,992,152 8.28 % 1,383,475 5.75 % 1,684,231 7.00 % 1,563,929 6.50 % Total capital (to risk-weighted assets) Company 2,768,153 11.50 % 2,227,221 9.25 % 2,528,196 10.50 % N/A N/A Bank 2,567,961 10.67 % 2,225,591 9.25 % 2,526,347 10.50 % 2,406,044 10.00 % Tier 1 capital (to risk-weighted assets) Company 2,293,016 9.52 % 1,745,659 7.25 % 2,046,635 8.50 % N/A N/A Bank 2,151,338 8.94 % 1,744,382 7.25 % 2,045,138 8.50 % 1,924,835 8.00 % Tier 1 capital (to average assets)(1) Company 2,293,016 9.15 % 1,002,494 4.00 % 1,002,494 4.00 % N/A N/A Bank 2,151,338 8.59 % 1,002,144 4.00 % 1,002,144 4.00 % 1,252,680 5.00 % (1) The Tier 1 capital ratio (to average assets) is not impacted by the Basel III Capital Rules; however, it should be noted that the Federal Reserve Board and the FDIC may require the Company and the Bank, respectively, to maintain a Tier 1 capital ratio (to average assets) above the required minimum.

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	9 Months Ended
	Sep. 30, 2018
Compensation Related Costs [Abstract]
Schedule of stock-based compensation costs	tock-based compensation expense for the three and nine months ended September 30, 2018 and 2017 (in thousands): Three months ended September 30, Nine months ended September 30, 2018 2017 2018 2017 Stock-settled awards: SARs $ 19 $ 64 $ 112 $ 210 RSUs 2,261 2,184 6,235 5,491 Restricted stock 12 8 36 16 Cash-settled performance units 2,144 3,811 9,250 9,304 Total $ 4,436 $ 6,067 $ 15,633 $ 15,021
Schedule of unrecognized compensation costs	(in thousands) September 30, 2018 Unrecognized compensation expense related to unvested stock-settled awards $ 17,487 Weighted average period over which expense is expected to be recognized, in years 2.8

INCOME TAXES (Tables)

INCOME TAXES (Tables)	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Reconciliation	The reconciliation of our total effective income tax rate to the U.S. federal statutory tax rate for the nine months ended September 30, 2018 and 2017 is as follows: Nine months ended September 30, 2018 2017 U.S. statutory rate 21 % 35 % State taxes 1 % 1 % Non-deductible expenses 1 % — % Non-taxable income (1 )% (1 )% Other (1 )% (1 )% Effective tax rate 21 % 34 %

FAIR VALUE DISCLOSURES (Tables)

FAIR VALUE DISCLOSURES (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Schedule of assets and liabilities measured at fair value	Assets and liabilities measured at fair value at September 30, 2018 and December 31, 2017 are as follows (in thousands): Fair Value Measurements Using September 30, 2018 Level 1 Level 2 Level 3 Available-for-sale debt securities:(1) Residential mortgage-backed securities $ — $ 7,709 $ — Tax-exempt asset-backed securities — — 93,369 Equity securities(1)(2) 9,461 6,850 — Loans held for sale (3) — 1,630,017 21,913 Loans held for investment(4)(6) — — 19,823 OREO(5)(6) — — 79 Derivative assets(7) — 35,781 — Derivative liabilities(7) — 27,381 — Non-qualified deferred compensation plan liabilities (8) 10,467 — — December 31, 2017 Available-for-sale debt securities:(1) Residential mortgage-backed securities $ — $ 10,945 $ — Equity securities(1)(2) 5,460 7,106 — Loans held for sale(3) — 1,007,695 — Loans held for investment(4)(6) — — 21,216 OREO(5)(6) — — 11,742 Derivative assets(7) — 16,719 — Derivative liabilities(7) — 17,377 — Non-qualified deferred compensation plan liabilities (8) 5,587 — — (1) Securities are measured at fair value on a recurring basis, generally monthly, except for tax-exempt asset-backed securities which are measured quarterly. (2) Equity securities consist of Community Reinvestment Act funds and investments related to our non-qualified deferred compensation plan. (3) Loans held for sale, excluding SBA loans which are carried at lower of cost or market, are measured at fair value on a recurring basis, generally monthly. (4) Includes impaired loans that have been measured for impairment at the fair value of the loan’s collateral. (5) OREO is transferred from loans to OREO at fair value less selling costs. (6) Loans held for investment and OREO are measured on a nonrecurring basis, generally annually or more often as warranted by market and economic conditions. (7) Derivative assets and liabilities are measured at fair value on a recurring basis, generally quarterly. (8) Non-qualified deferred compensation plan liabilities represent the fair value of the obligation to the employee, which corresponds to the fair value of the invested assets, and are measured at fair value on a recurring basis, generally monthly.
Summary of the carrying amounts and estimated fair values of financial instruments	A summary of the carrying amounts and estimated fair values of financial instruments is as follows (in thousands): September 30, 2018 December 31, 2017 Carrying Amount Estimated Fair Value Carrying Estimated Financial assets: Level 1 inputs: Cash and cash equivalents $ 2,785,051 $ 2,785,051 $ 2,905,591 $ 2,905,591 Investment securities 9,461 9,461 5,460 5,460 Level 2 inputs: Investment securities 14,559 14,559 18,051 18,051 Loans held for sale 1,630,017 1,630,017 1,011,004 1,011,004 Derivative assets 35,781 35,781 16,719 16,719 Level 3 inputs: Investment securities 93,369 93,369 — — Loans held for sale 21,913 21,913 — — Loans held for investment, net 21,857,019 21,843,389 20,489,757 20,480,802 Financial liabilities: Level 2 inputs: Federal funds purchased 475,842 475,842 359,338 359,338 Customer repurchase agreements 10,976 10,976 5,702 5,702 Other borrowings 3,200,000 3,200,000 2,800,000 2,800,000 Subordinated notes 281,677 282,247 281,406 285,485 Derivative liabilities 27,381 27,381 17,377 17,377 Level 3 inputs: Deposits 20,385,637 20,386,435 19,123,180 19,124,121 Trust preferred subordinated debentures 113,406 113,406 113,406 113,406
Reconciliation of loans held for sale	The following table presents a reconciliation for the three and nine months ended September 30, 2018 of the level 3 fair value category measured at fair value on a recurring basis using Level 3 inputs (in thousands): Net Realized/Unrealized Gains (Losses) Balance at Beginning of Period Purchases / Additions Sales / Reductions Realized Unrealized Balance at End of Period Three months ended September 30, 2018 Tax-exempt asset-backed securities(1) $ — $ 95,521 $ — $ — $ (2,152 ) $ 93,369 Loans held for sale(2) $ 27,929 $ 901 $ (6,948 ) $ (134 ) $ 165 $ 21,913 Nine months ended September 30, 2018 Tax-exempt asset-backed securities $ — $ 95,521 $ — $ — $ (2,152 ) $ 93,369 Loans held for sale $ — $ 38,430 $ (14,936 ) $ (66 ) $ (1,515 ) $ 21,913

DERIVATIVE FINANCIAL INSTRUME_2

DERIVATIVE FINANCIAL INSTRUMENTS (Tables)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of notional amounts and estimated fair values of interest rate derivative positions	The notional amounts and estimated fair values of interest rate derivative positions outstanding at September 30, 2018 and December 31, 2017 are presented in the following tables (in thousands): September 30, 2018 December 31, 2017 Estimated Fair Value Estimated Fair Value Notional Amount Asset Derivative Liability Derivative Notional Amount Asset Derivative Liability Derivative Non-hedging interest rate derivatives: Financial institution counterparties: Commercial loan/lease interest rate swaps $ 1,593,483 $ 21,796 $ 4,691 $ 1,393,764 $ 4,736 $ 15,482 Commercial loan/lease interest rate caps 567,490 2,525 17 242,700 421 7 Foreign currency forward contracts 50,975 2,441 — 2,466 4 69 Customer counterparties: Commercial loan/lease interest rate swaps 1,593,483 4,691 21,796 1,393,764 15,482 4,736 Commercial loan/lease interest rate caps 567,490 17 2,525 242,700 7 421 Foreign currency forward contracts 50,975 — 2,441 2,466 69 4 Economic hedging interest rate derivatives: Loan purchase commitments 308,933 1,104 81 253,815 635 190 Forward sales commitments 1,851,500 7,441 64 1,086,224 — 1,103 Gross derivatives 40,015 31,615 21,354 22,012 Offsetting derivative assets/liabilities (4,234 ) (4,234 ) (4,635 ) (4,635 ) Net derivatives included in the consolidated balance sheets $ 35,781 $ 27,381 $ 16,719 $ 17,377
Schedule of the weighted-average receive and pay interest rate swaps	The weighted average received and paid interest rates for interest rate swaps outstanding at September 30, 2018 and December 31, 2017 were as follows: September 30, 2018 December 31, 2017 Received Paid Received Paid Non-hedging interest rate swaps 3.92 % 4.17 % 3.59 % 4.34 %

EARNINGS PER COMMON SHARE (Deta

EARNINGS PER COMMON SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator:
Net income		$ 85,552	$ 58,684	$ 228,933	$ 152,321
Preferred stock dividends		2,438	2,438	7,313	7,313
Net income available to common stockholders		$ 83,114	$ 56,246	$ 221,620	$ 145,008
Denominator:
Denominator for basic earnings per share—weighted average shares		50,163,433	49,607,028	49,853,515	49,573,456
Effect of employee stock-based awards	[1]	207,391	214,468	240,376	235,011
Effect of warrants to purchase common stock		10,525	429,370	115,537	431,551
Denominator for dilutive earnings per share—adjusted weighted average shares and assumed conversions		50,381,349	50,250,866	50,209,428	50,240,018
Basic earnings per common share (usd per share)		$ 1.66	$ 1.13	$ 4.45	$ 2.93
Diluted earnings per common share (usd per share)		$ 1.65	$ 1.12	$ 4.41	$ 2.89
Stock options, SARs and RSUs excluded from computation of diluted EPS				4,000	6,200
[1]	SARs and RSUs outstanding of 4,000 at September 30, 2018 and 6,200 at September 30, 2017 have not been included in diluted earnings per share because to do so would have been anti-dilutive for the periods presented.

INVESTMENT SECURITIES (Details)

INVESTMENT SECURITIES (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Summary of Available-for-Sale Securities
Amortized Cost	$ 102,820
Gross Unrealized Gains	410
Gross Unrealized Losses	2,152
Estimated Fair Value	101,078
Residential mortgage-backed securities
Summary of Available-for-Sale Securities
Amortized Cost	7,299	$ 10,297
Gross Unrealized Gains	410	648
Gross Unrealized Losses	0	0
Estimated Fair Value	7,709	$ 10,945
Tax-exempt asset-backed securities
Summary of Available-for-Sale Securities
Amortized Cost	95,521
Gross Unrealized Gains	0
Gross Unrealized Losses	2,152
Estimated Fair Value	$ 93,369

INVESTMENT SECURITIES (Details

INVESTMENT SECURITIES (Details 1) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Sep. 30, 2018	Dec. 31, 2017
The amortized cost and fair value of available-for-sale securites by maturity
Estimated Fair Value		$ 117,389	$ 23,511
Estimated Fair Value		16,300	12,600
Available-for-sale Debt Securities, Amortized Cost Basis		102,820
Available-for-sale Securities, Other Disclosure Items
Estimated Fair Value		101,078
Residential mortgage-backed securities
The amortized cost and fair value of available-for-sale securites by maturity
Amortized cost, Less Than One Year	[1]	12	409
Amortized cost, After One Through Five Years	[1]	1,727	819
Amortized cost, After Five Through Ten Years	[1]	0	1,502
Amortized cost, After Ten Years	[1]	5,560	7,567
Amortized Cost	[1]	7,299	10,297
Estimated fair value, Less Than One Year	[1]	13	418
Estimated fair value, After One Through Five Years	[1]	1,846	916
Estimated fair value, After Five Through Ten Years	[1]	0	1,636
Estimated fair value, After Ten Years	[1]	5,850	7,975
Estimated Fair Value	[1]	$ 7,709	$ 10,945
Weighted average yield, Less Than One Year	[1]	6.23%	4.59%
Weighted average yield, After One Through Five Years	[1]	5.55%	6.02%
Weighted average yield, After Five Through Ten Years	[1]	0.00%	5.32%
Weighted average yield, After Ten Years	[1]	3.79%	3.45%
Weighted average yield, Total	[1]	4.21%	3.97%
Available-for-sale Debt Securities, Amortized Cost Basis		$ 7,299	$ 10,297
Available-for-sale Securities, Other Disclosure Items
Estimated Fair Value		7,709	10,945
Deposits
Available-for-sale Securities, Other Disclosure Items
Available-for-sale securities pledged as collateral		1,900
Repurchase agreements
Available-for-sale Securities, Other Disclosure Items
Available-for-sale securities pledged as collateral		5,100
Tax-exempt asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Payments to acquire AFS securities, debt		95,500
The amortized cost and fair value of available-for-sale securites by maturity
Amortized cost, Less Than One Year	[1]	0
Amortized cost, After One Through Five Years	[1]	0
Amortized cost, After Five Through Ten Years	[1]	0
Amortized cost, After Ten Years	[1]	95,521
Amortized Cost	[1]	95,521
Estimated fair value, Less Than One Year	[1]	0
Estimated fair value, After One Through Five Years	[1]	0
Estimated fair value, After Five Through Ten Years	[1]	0
Estimated fair value, After Ten Years	[1]	93,369
Estimated Fair Value	[1]	$ 93,369
Weighted average yield, Less Than One Year	[1]	0.00%
Weighted average yield, After One Through Five Years	[1]	0.00%
Weighted average yield, After Five Through Ten Years	[1]	0.00%
Weighted average yield, After Ten Years	[1]	4.25%
Weighted average yield, Total	[1]	4.25%
Available-for-sale Debt Securities, Amortized Cost Basis		$ 95,521
Available-for-sale Securities, Other Disclosure Items
Estimated Fair Value		$ 93,369
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Available-for-sale Securities, Other Disclosure Items
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent			$ 10
[1]	Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without prepayment penalties.

INVESTMENT SECURITIES (Detail_2

INVESTMENT SECURITIES (Details 3) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018
Available-for-sale Securities [Abstract]
Realized Investment Gains (Losses)	$ 253	$ 149
Gain (Loss) on Sale of Equity Investments	18	180
Unrealized Gain (Loss) on Investments	$ 235	$ (31)

INVESTMENT SECURITIES Details 4

INVESTMENT SECURITIES Details 4 (Details) $ in Thousands	Sep. 30, 2018USD ($)
Available-for-sale Securities [Abstract]
Less Than 12 Months, Fair Value	$ 93,369
Less Than 12 Months, Unrealized Loss	(2,152)
12 Months or Longer, Fair Value	0
12 Months or Longer, Unrealized Loss	0
Total, Fair Value	93,369
Total, Unrealized Loss	$ (2,152)

LOANS AND ALLOWANCE FOR LOAN _3

LOANS AND ALLOWANCE FOR LOAN LOSSES (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Loans and Leases Receivable, Net Reported Amount
Commercial	$ 10,116,945	$ 9,189,811
Mortgage finance	5,477,787	5,308,160
Construction	2,263,463	2,166,208
Real estate	3,924,682	3,794,577
Consumer	51,692	48,684
Leases	319,411	264,903
Gross loans held for investment	22,153,980	20,772,343	$ 20,566,185
Deferred income (net of direct origination costs)	(106,655)	(97,931)
Allowance for loan losses	(190,306)	(184,655)		$ (182,929)	$ (168,126)
Loans held for investment, net	21,857,019	20,489,757
Participating mortgage finance loans	$ 174,100	$ 171,200

LOANS AND ALLOWANCE FOR LOAN _4

LOANS AND ALLOWANCE FOR LOAN LOSSES - Credit Risk Profile (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Financing Receivable, Recorded Investment [Line Items]
Commercial	$ 10,116,945	$ 9,189,811
Mortgage finance	5,477,787	5,308,160
Construction	2,263,463	2,166,208
Real estate	3,924,682	3,794,577
Consumer	51,692	48,684
Leases	319,411	264,903
Gross loans held for investment	22,153,980	20,772,343	$ 20,566,185
Pass
Financing Receivable, Recorded Investment [Line Items]
Commercial	9,851,525	8,967,471
Mortgage finance	5,477,787	5,308,160
Construction	2,250,650	2,152,654
Real estate	3,845,393	3,706,541
Consumer	50,064	48,591
Leases	318,969	249,865
Gross loans held for investment	21,794,388	20,433,282
Special mention
Financing Receivable, Recorded Investment [Line Items]
Commercial	96,168	19,958
Mortgage finance	0	0
Construction	12,813	13,554
Real estate	44,486	53,652
Consumer	0	0
Leases	442	495
Gross loans held for investment	153,909	87,659
Substandard-accruing
Financing Receivable, Recorded Investment [Line Items]
Commercial	64,295	102,651
Mortgage finance	0	0
Construction	0	0
Real estate	32,288	32,671
Consumer	1,568	93
Leases	0	14,543
Gross loans held for investment	98,151	149,958
Non-accrual
Financing Receivable, Recorded Investment [Line Items]
Commercial	104,957	99,731
Mortgage finance	0	0
Construction	0	0
Real estate	2,515	1,713
Consumer	60	0
Leases	0	0
Gross loans held for investment	$ 107,532	$ 101,444

LOANS AND ALLOWANCE FOR LOAN _5

LOANS AND ALLOWANCE FOR LOAN LOSSES (Details 2) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable Modifications Non Accrual Loans Met Criteria For Restrucutred			$ 22,500	$ 18,800
Reserve for loan losses:
Beginning balance	$ 184,655	$ 168,126
Provision for loan losses	50,788	43,661
Charge-offs	46,359	32,675
Recoveries	1,222	3,817
Net charge-offs (recoveries)	45,137	28,858
Period end amount allocated to:
Loans individually evaluated for impairment			30,935		$ 24,436
Loans collectively evaluated for impairment			159,371		158,493
Ending balance	184,655	168,126	190,306	184,655	182,929
Commercial
Reserve for loan losses:
Beginning balance	118,806	128,768
Provision for loan losses	55,808	21,388
Charge-offs	45,273	32,146
Recoveries	1,069	3,574
Net charge-offs (recoveries)	44,204	28,572
Period end amount allocated to:
Loans individually evaluated for impairment			30,855		24,410
Loans collectively evaluated for impairment			99,555		97,174
Ending balance	118,806	128,768	130,410	118,806	121,584
Mortgage finance loans
Reserve for loan losses:
Beginning balance	0	0
Provision for loan losses	0	0
Charge-offs	0	0
Recoveries	0	0
Net charge-offs (recoveries)	0	0
Period end amount allocated to:
Loans individually evaluated for impairment			0		0
Loans collectively evaluated for impairment			0		0
Ending balance	0	0	0	0	0
Construction
Reserve for loan losses:
Beginning balance	19,273	13,144
Provision for loan losses	331	4,431
Charge-offs	0	59
Recoveries	0	104
Net charge-offs (recoveries)	0	(45)
Period end amount allocated to:
Loans individually evaluated for impairment			0		0
Loans collectively evaluated for impairment			19,604		17,620
Ending balance	19,273	13,144	19,604	19,273	17,620
Real Estate
Reserve for loan losses:
Beginning balance	34,287	19,149
Provision for loan losses	(1,635)	12,948
Charge-offs	0	290
Recoveries	43	74
Net charge-offs (recoveries)	(43)	216
Period end amount allocated to:
Loans individually evaluated for impairment			70		26
Loans collectively evaluated for impairment			32,625		31,855
Ending balance	34,287	19,149	32,695	34,287	31,881
Consumer
Reserve for loan losses:
Beginning balance	357	241
Provision for loan losses	757	221
Charge-offs	767	180
Recoveries	78	56
Net charge-offs (recoveries)	689	124
Period end amount allocated to:
Loans individually evaluated for impairment			10		0
Loans collectively evaluated for impairment			415		338
Ending balance	357	241	425	357	338
Leases
Reserve for loan losses:
Beginning balance	3,542	1,124
Provision for loan losses	(1,425)	2,774
Charge-offs	319	0
Recoveries	32	9
Net charge-offs (recoveries)	287	(9)
Period end amount allocated to:
Loans individually evaluated for impairment			0		0
Loans collectively evaluated for impairment			1,830		3,907
Ending balance	3,542	1,124	1,830	3,542	3,907
Unallocated
Reserve for loan losses:
Beginning balance	8,390	5,700
Provision for loan losses	(3,048)	1,899
Charge-offs	0	0
Recoveries	0	0
Net charge-offs (recoveries)	0	0
Period end amount allocated to:
Loans individually evaluated for impairment			0		0
Loans collectively evaluated for impairment			5,342		7,599
Ending balance	$ 8,390	$ 5,700	$ 5,342	$ 8,390	$ 7,599

LOANS AND ALLOWANCE FOR LOAN _6

LOANS AND ALLOWANCE FOR LOAN LOSSES - Allowance for Credit Losses Related to Unfunded Commitments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Provision for off-balance sheet credit losses	$ 13,000	$ 20,000	$ 52,000	$ 42,000
Unfunded Loan Commitment
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	10,458	9,205	9,071	11,422
Provision for off-balance sheet credit losses	(175)	556	1,212	(1,661)
Ending balance	$ 10,283	$ 9,761	$ 10,283	$ 9,761

LOANS AND ALLOWANCE FOR LOAN _7

LOANS AND ALLOWANCE FOR LOAN LOSSES (Details 3) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans individually evaluated for impairment	$ 114,639	$ 102,684	$ 119,543
Loans collectively evaluated for impairment	22,039,341	20,669,659	20,446,642
Gross loans held for investment	22,153,980	20,772,343	20,566,185
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans individually evaluated for impairment	105,522	100,676	117,426
Loans collectively evaluated for impairment	10,011,423	9,089,135	8,693,399
Gross loans held for investment	10,116,945	9,189,811	8,810,825
Mortgage finance loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans individually evaluated for impairment	0	0	0
Loans collectively evaluated for impairment	5,477,787	5,308,160	5,642,285
Gross loans held for investment	5,477,787	5,308,160	5,642,285
Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans individually evaluated for impairment	0	0	0
Loans collectively evaluated for impairment	2,263,463	2,166,208	2,099,355
Gross loans held for investment	2,263,463	2,166,208	2,099,355
Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans individually evaluated for impairment	9,057	2,008	2,117
Loans collectively evaluated for impairment	3,915,625	3,792,569	3,681,447
Gross loans held for investment	3,924,682	3,794,577	3,683,564
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans individually evaluated for impairment	60	0	0
Loans collectively evaluated for impairment	51,632	48,684	70,436
Gross loans held for investment	51,692	48,684	70,436
Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans individually evaluated for impairment	0	0	0
Loans collectively evaluated for impairment	319,411	264,903	259,720
Gross loans held for investment	$ 319,411	$ 264,903	$ 259,720

LOANS AND ALLOWANCE FOR LOAN _8

LOANS AND ALLOWANCE FOR LOAN LOSSES (Details 4) $ in Millions	Sep. 30, 2018USD ($)
Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract]
Non-accrual loans earning on a cash basis	$ 0

LOANS AND ALLOWANCE FOR LOAN _9

LOANS AND ALLOWANCE FOR LOAN LOSSES (Details 5) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Commercial business loans | Energy
Financing Receivable, Impaired [Line Items]
Recorded investment			$ 21,426
With no related allowance recorded:
Financing Receivable, Impaired [Line Items]
Recorded investment	$ 36,266		39,357
Unpaid principal balance	44,201		41,955
Related allowance	0		0
Average recorded investment	37,046		61,709
Interest income recognized	133		0
With no related allowance recorded: | Commercial business loans | Business loans
Financing Receivable, Impaired [Line Items]
Recorded investment	14,669		16,835
Unpaid principal balance	21,428		18,257
Related allowance	0		0
Average recorded investment	16,045		22,964
Interest income recognized	133		0
With no related allowance recorded: | Commercial business loans | Energy
Financing Receivable, Impaired [Line Items]
Recorded investment	12,777
Unpaid principal balance	13,953		22,602
Related allowance	0		0
Average recorded investment	18,653		36,579
Interest income recognized	0		0
With no related allowance recorded: | Construction | Market risk
Financing Receivable, Impaired [Line Items]
Recorded investment	0		0
Unpaid principal balance	0		0
Related allowance	0		0
Average recorded investment	0		0
Interest income recognized	0		0
With no related allowance recorded: | Real estate | Market risk
Financing Receivable, Impaired [Line Items]
Recorded investment	0		0
Unpaid principal balance	0		0
Related allowance	0		0
Average recorded investment	0		0
Interest income recognized	0		0
With no related allowance recorded: | Real estate | Commercial
Financing Receivable, Impaired [Line Items]
Recorded investment	7,557		1,096
Unpaid principal balance	7,557		1,096
Related allowance	0		0
Average recorded investment	1,787		2,166
Interest income recognized	0		0
With no related allowance recorded: | Real estate | Secured by 1-4 family
Financing Receivable, Impaired [Line Items]
Recorded investment	1,263		0
Unpaid principal balance	1,263		0
Related allowance	0		0
Average recorded investment	561		0
Interest income recognized	0		0
With no related allowance recorded: | Consumer
Financing Receivable, Impaired [Line Items]
Recorded investment	0		0
Unpaid principal balance	0		0
Related allowance	0		0
Average recorded investment	0		0
Interest income recognized	0		0
With no related allowance recorded: | Leases
Financing Receivable, Impaired [Line Items]
Recorded investment	0		0
Unpaid principal balance	0		0
Related allowance	0		0
Average recorded investment	0		0
Interest income recognized	0		0
With an allowance recorded:
Financing Receivable, Impaired [Line Items]
Recorded investment	78,373		63,327
Unpaid principal balance	98,319		75,807
Related allowance	30,935		24,417
Average recorded investment	67,960		69,068
Interest income recognized	0		6
With an allowance recorded: | Commercial business loans | Business loans
Financing Receivable, Impaired [Line Items]
Recorded investment	59,618		18,645
Unpaid principal balance	78,304		19,020
Related allowance	24,180		2,544
Average recorded investment	39,880		16,960
Interest income recognized	0		0
With an allowance recorded: | Commercial business loans | Energy
Financing Receivable, Impaired [Line Items]
Recorded investment	18,458		43,770
Unpaid principal balance	19,718		55,875
Related allowance	6,675		21,772
Average recorded investment	27,312		50,867
Interest income recognized	0		6
With an allowance recorded: | Construction | Market risk
Financing Receivable, Impaired [Line Items]
Recorded investment	0		0
Unpaid principal balance	0		0
Related allowance	0		0
Average recorded investment	0		27
Interest income recognized	0		0
With an allowance recorded: | Real estate | Market risk
Financing Receivable, Impaired [Line Items]
Recorded investment	0		295
Unpaid principal balance	0		295
Related allowance	0		6
Average recorded investment	66		485
Interest income recognized	0		0
With an allowance recorded: | Real estate | Commercial
Financing Receivable, Impaired [Line Items]
Recorded investment	0		499
Unpaid principal balance	0		499
Related allowance	0		75
Average recorded investment	111		166
Interest income recognized	0		0
With an allowance recorded: | Real estate | Secured by 1-4 family
Financing Receivable, Impaired [Line Items]
Recorded investment	237		118
Unpaid principal balance	237		118
Related allowance	70		20
Average recorded investment	171		516
Interest income recognized	0		0
With an allowance recorded: | Consumer
Financing Receivable, Impaired [Line Items]
Recorded investment	60		0
Unpaid principal balance	60		0
Related allowance	10		0
Average recorded investment	53		33
Interest income recognized	0		0
With an allowance recorded: | Leases
Financing Receivable, Impaired [Line Items]
Recorded investment	0		0
Unpaid principal balance	0		0
Related allowance	0		0
Average recorded investment	367		14
Interest income recognized	0		0
Combined:
Financing Receivable, Impaired [Line Items]
Recorded investment	114,639		102,684
Unpaid principal balance	142,520		117,762
Related allowance	30,935		24,417
Average recorded investment	105,006	$ 135,900	130,777
Interest income recognized	133		6
Combined: | Commercial business loans | Business loans
Financing Receivable, Impaired [Line Items]
Recorded investment	74,287		35,480
Unpaid principal balance	99,732		37,277
Related allowance	24,180		2,544
Average recorded investment	55,925		39,924
Interest income recognized	133		0
Combined: | Commercial business loans | Energy
Financing Receivable, Impaired [Line Items]
Recorded investment	31,235		65,196
Unpaid principal balance	33,671		78,477
Related allowance	6,675		21,772
Average recorded investment	45,965		87,446
Interest income recognized	0		6
Combined: | Construction | Market risk
Financing Receivable, Impaired [Line Items]
Recorded investment	0		0
Unpaid principal balance	0		0
Related allowance	0		0
Average recorded investment	0		27
Interest income recognized	0		0
Combined: | Real estate | Market risk
Financing Receivable, Impaired [Line Items]
Recorded investment	0		295
Unpaid principal balance	0		295
Related allowance	0		6
Average recorded investment	66		485
Interest income recognized	0		0
Combined: | Real estate | Commercial
Financing Receivable, Impaired [Line Items]
Recorded investment	7,557		1,595
Unpaid principal balance	7,557		1,595
Related allowance	0		75
Average recorded investment	1,898		2,332
Interest income recognized	0		0
Combined: | Real estate | Secured by 1-4 family
Financing Receivable, Impaired [Line Items]
Recorded investment	1,500		118
Unpaid principal balance	1,500		118
Related allowance	70		20
Average recorded investment	732		516
Interest income recognized	0		0
Combined: | Consumer
Financing Receivable, Impaired [Line Items]
Recorded investment	60		0
Unpaid principal balance	60		0
Related allowance	10		0
Average recorded investment	53		33
Interest income recognized	0		0
Combined: | Leases
Financing Receivable, Impaired [Line Items]
Recorded investment	0		0
Unpaid principal balance	0		0
Related allowance	0		0
Average recorded investment	367		14
Interest income recognized	$ 0		$ 0

LOANS AND ALLOWANCE FOR LOAN_10

LOANS AND ALLOWANCE FOR LOAN LOSSES (Details 6) $ in Thousands	Sep. 30, 2018USD ($)
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	$ 91,412
Non-accrual	107,532
Current	21,955,036
Total	22,153,980
Premium finance loans past due 90 days and still accruing	8,200
Commercial business loans | Business loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	65,340
Non-accrual	73,722
Current	8,488,962
Total	8,628,024
Commercial business loans | Energy
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	15,281
Non-accrual	31,235
Current	1,442,405
Total	1,488,921
Mortgage finance loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0
Non-accrual	0
Current	5,477,787
Total	5,477,787
Construction | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0
Non-accrual	0
Current	2,182,653
Total	2,182,653
Construction | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0
Non-accrual	0
Current	53,116
Total	53,116
Construction | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0
Non-accrual	0
Current	27,694
Total	27,694
Real estate | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	4,884
Non-accrual	0
Current	2,759,177
Total	2,764,061
Real estate | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	4,192
Non-accrual	1,015
Current	814,646
Total	819,853
Real estate | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	1,623
Non-accrual	1,500
Current	337,645
Total	340,768
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0
Non-accrual	60
Current	51,632
Total	51,692
Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	92
Non-accrual	0
Current	319,319
Total	319,411
30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	73,447
30-59 Days Past Due | Commercial business loans | Business loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	51,154
30-59 Days Past Due | Commercial business loans | Energy
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	13,000
30-59 Days Past Due | Mortgage finance loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0
30-59 Days Past Due | Construction | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0
30-59 Days Past Due | Construction | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0
30-59 Days Past Due | Construction | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0
30-59 Days Past Due | Real estate | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	3,471
30-59 Days Past Due | Real estate | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	4,192
30-59 Days Past Due | Real estate | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	1,538
30-59 Days Past Due | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0
30-59 Days Past Due | Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	92
60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	6,670
60-89 Days Past Due | Commercial business loans | Business loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	4,304
60-89 Days Past Due | Commercial business loans | Energy
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	2,281
60-89 Days Past Due | Mortgage finance loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0
60-89 Days Past Due | Construction | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0
60-89 Days Past Due | Construction | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0
60-89 Days Past Due | Construction | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0
60-89 Days Past Due | Real estate | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0
60-89 Days Past Due | Real estate | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0
60-89 Days Past Due | Real estate | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	85
60-89 Days Past Due | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0
60-89 Days Past Due | Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0
Greater Than 90 Days and Accruing(1)
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	11,295	[1]
Greater Than 90 Days and Accruing(1) | Commercial business loans | Business loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	9,882	[1]
Greater Than 90 Days and Accruing(1) | Commercial business loans | Energy
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	[1]
Greater Than 90 Days and Accruing(1) | Mortgage finance loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	[1]
Greater Than 90 Days and Accruing(1) | Construction | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	[1]
Greater Than 90 Days and Accruing(1) | Construction | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	[1]
Greater Than 90 Days and Accruing(1) | Construction | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	[1]
Greater Than 90 Days and Accruing(1) | Real estate | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	1,413	[1]
Greater Than 90 Days and Accruing(1) | Real estate | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	[1]
Greater Than 90 Days and Accruing(1) | Real estate | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	[1]
Greater Than 90 Days and Accruing(1) | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	[1]
Greater Than 90 Days and Accruing(1) | Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	$ 0	[1]
[1]	Loans past due 90 days and still accruing includes premium finance loans of $8.2 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.

LOANS AND ALLOWANCE FOR LOAN_11

LOANS AND ALLOWANCE FOR LOAN LOSSES (Details 7) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)
Financing Receivable, Modifications [Line Items]
Number of restructured loans	7	2
Pre-restructuring outstanding recorded investment	$ 14,940	$ 1,669
Post-restructuring outstanding recorded investment	$ 14,914	$ 721
Energy loans
Financing Receivable, Modifications [Line Items]
Number of restructured loans	5	1
Pre-restructuring outstanding recorded investment	$ 12,358	$ 1,070
Post-restructuring outstanding recorded investment	$ 12,332	$ 0
Commercial business loans
Financing Receivable, Modifications [Line Items]
Number of restructured loans	2	1
Pre-restructuring outstanding recorded investment	$ 2,582	$ 599
Post-restructuring outstanding recorded investment	$ 2,582	$ 721

LOANS AND ALLOWANCE FOR LOAN_12

LOANS AND ALLOWANCE FOR LOAN LOSSES - TDR Summary (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2017
Financing Receivable, Modifications [Line Items]
Details of how restructured loans were modified	$ 14,914	$ 721
Extended maturity
Financing Receivable, Modifications [Line Items]
Details of how restructured loans were modified	0	721
Adjusted payment schedule
Financing Receivable, Modifications [Line Items]
Details of how restructured loans were modified	$ 14,914	$ 0

OREO AND VALUATION ALLOWANCE _3

OREO AND VALUATION ALLOWANCE FOR LOSSES ON OREO (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Real Estate Owned, Disclosure of Detailed Components [Abstract]
Gains (Losses) on Sales of Other Real Estate	$ 2,000
Real Estate Acquired Through Foreclosure [Roll Forward]
Beginning balance	9,526	$ 18,689	$ 11,742	$ 18,961
Additions	0	0	0	0
Sales	(11,447)	(457)	(11,663)	(729)
Valuation allowance for OREO	(2,000)	101	0	101
Ending balance	$ 79	$ 18,131	$ 79	$ 18,131

CERTAIN TRANSFERS OF FINANCIA_3

CERTAIN TRANSFERS OF FINANCIAL ASSETS (Details) - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Loans and Leases Receivable Disclosure [Line Items]
Fair value over/(under) outstanding balance	$ (6,700,000)		$ (1,576,000)
Outstanding principal balance of loans in servicing portfolio Financial Assets, Principal Amount Outstanding	7,300,000,000		7,000,000,000
Escrow fund deposits related to servicing assets	96,500,000		73,400,000
Estimated exposure related to servicing assets	1,600,000		1,300,000
Loss Contingency Accrual, Payments	187,000
Losses due to repurchase, indemnification or make-whole obligations		$ 14,000
Total past due	91,412,000
Loans held for sale, at fair value	1,651,930,000		1,011,004,000
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Maturity Greater than 90 Days [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total past due	25,200,000		19,700,000
Government Guaranteed Mortgage Loans upon Foreclosure Receivable [Member] | Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Maturity Greater than 90 Days [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total past due	5,000,000		19,000,000
Loans held for sale, at fair value	$ 19,800,000
Small Business Administration Loans [Member] | Disposal Group, Held-for-sale, Not Discontinued Operations [Member]
Loans and Leases Receivable Disclosure [Line Items]
Fair value over/(under) outstanding balance			$ 3,300,000

CERTAIN TRANSFERS OF FINANCIA_4

CERTAIN TRANSFERS OF FINANCIAL ASSETS (Details 1) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Transfers and Servicing [Abstract]
Unpaid principal balance	$ 1,658,630	$ 1,009,271
Fair value	1,651,930	1,007,695
Fair value over/(under) outstanding balance	$ (6,700)	(1,576)
Loans held for sale carried at lower of cost or market		$ 0

CERTAIN TRANSFERS OF FINANCIA_5

CERTAIN TRANSFERS OF FINANCIAL ASSETS (Details 2) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Transfers and Servicing [Abstract]
Gain (Loss) on Sale of Notes Receivable	$ 7,800	$ 1,000
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Beginning balance	1,011,004	968,929
Loans purchased	5,012,188	4,315,065
Payments and loans sold	(4,366,138)	(4,337,919)
Change in fair value	(5,124)	9,908
Ending balance	$ 1,651,930	$ 955,983
Loans held for sale carried at lower of cost or market			$ 0

CERTAIN TRANSFERS OF FINANCIA_6

CERTAIN TRANSFERS OF FINANCIAL ASSETS (Details 3) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Valuation allowance:
MSRs, net(1)	$ 86,359	$ 77,630
MSR
MSRs:
Balance, beginning of year	88,150	28,536
Capitalized servicing rights	32,871	54,614
Amortization	(7,920)	(5,304)
Sales	(26,742)	0
Balance, end of period	86,359	77,846
Valuation allowance:
Balance, beginning of year	2,823	0
Increase (decrease) in valuation allowance	(2,823)	216
Balance, end of period	0	216
MSRs, net(1)	$ 98,391	$ 78,940

CERTAIN TRANSFERS OF FINANCIA_7

CERTAIN TRANSFERS OF FINANCIAL ASSETS (Details 4) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended		12 Months Ended
	Dec. 31, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Servicing Assets at Fair Value [Line Items]
Impairment charges		$ 0	$ 5,285
Average discount rates (percent)		9.62%		9.90%
Expected prepayment speeds (percent)		8.31%		9.99%
Weighted average life, in years		7 years 10 months 24 days		7 years
Servicing Asset [Member]
Servicing Assets at Fair Value [Line Items]
Impairment charges	$ 2,800

CERTAIN TRANSFERS OF FINANCIA_8

CERTAIN TRANSFERS OF FINANCIAL ASSETS (Details 5) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Transfers and Servicing [Abstract]
50 bp adverse change in prepayment speed	$ (11,581)	$ (11,896)
100 bp adverse change in prepayment speed	$ (24,868)	$ (28,226)

FINANCIAL INSTRUMENTS WITH OF_3

FINANCIAL INSTRUMENTS WITH OFF-BALANCE SHEET RISK (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financing receivable allowance for credit losses off balance sheet liability	$ 10,300	$ 9,100
Commitments to extend credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet financial instruments whose contract amounts represented credit risk	7,510,397	6,957,847
Standby letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet financial instruments whose contract amounts represented credit risk	$ 235,471	$ 230,958

REGULATORY MATTERS (Details)

REGULATORY MATTERS (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2009
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Assets	$ 27,127,107	$ 27,127,107		$ 25,075,645	$ 15,000,000
Common Equity Tier 1 Capital	$ 2,258,596	$ 2,258,596		$ 2,033,830
Tier 1 capital	9.62%	9.62%		9.52%
Total capital	11.47%	11.47%		11.50%
Tier 1 leverage	9.70%	9.70%		9.15%
Mortgage finance	$ 5,477,787	$ 5,477,787		$ 5,308,160
Mortgage finance, average balance	$ 5,400,000
Common Equity Tier 1, Capital to Risk Weighted Assets	8.64%	8.64%		8.45%
Capital	$ 2,999,161	$ 2,999,161		$ 2,768,153
Tier One Risk Based Capital	2,516,895	2,516,895		2,293,016
Tier One Leverage Capital	2,516,895	$ 2,516,895		2,293,016
Common Stock, Dividends, Per Share, Declared		$ 0	$ 0
Common Stock, Dividends, Per Share, Cash Paid		$ 0	$ 0
Subsidiaries [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier 1 Capital	$ 2,266,454	$ 2,266,454		$ 1,992,152
Tier 1 capital	9.28%	9.28%		8.94%
Total capital	10.90%	10.90%		10.67%
Tier 1 leverage	9.35%	9.35%		8.59%
Common Equity Tier 1, Capital to Risk Weighted Assets	8.67%	8.67%		8.28%
Common Equity Tier 1, Capital Required to be Well Capitalized	$ 1,698,577	$ 1,698,577		$ 1,563,929
Common Equity Tier 1, Capital Required to be Well Capitalized to Risk Weighted Assets	6.50%	6.50%		6.50%
Capital	$ 2,848,430	$ 2,848,430		$ 2,567,961
Capital Required to be Well Capitalized	$ 2,613,196	$ 2,613,196		$ 2,406,044
Capital Required to be Well Capitalized to Risk Weighted Assets	10.00%	10.00%		10.00%
Tier One Risk Based Capital	$ 2,424,753	$ 2,424,753		$ 2,151,338
Tier One Risk Based Capital Required to be Well Capitalized	$ 2,090,557	$ 2,090,557		$ 1,924,835
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	8.00%	8.00%		8.00%
Tier One Leverage Capital	$ 2,424,753	$ 2,424,753		$ 2,151,338
Tier One Leverage Capital Required to be Well Capitalized	$ 1,297,245	$ 1,297,245		$ 1,252,680
Tier One Leverage Capital Required to be Well Capitalized to Average Assets	5.00%	5.00%		5.00%
Advanced Approach, Phase-In Schedule [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier 1, Capital Required for Capital Adequacy	$ 1,667,255	$ 1,667,255		$ 1,384,448
Common Equity Tier 1, Capital Required for Capital Adequacy to Risk Weighted Assets	6.38%	6.38%		5.75%
Capital Required for Capital Adequacy	$ 2,582,611	$ 2,582,611		$ 2,227,221
Capital Required for Capital Adequacy to Risk Weighted Assets	9.88%	9.88%		9.25%
Tier One Risk Based Capital Required for Capital Adequacy	$ 2,059,550	$ 2,059,550		$ 1,745,659
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	7.88%	7.88%		7.25%
Tier One Leverage Capital Required for Capital Adequacy	$ 1,038,268	$ 1,038,268		$ 1,002,494
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	4.00%	4.00%		4.00%
Advanced Approach, Phase-In Schedule [Member] | Subsidiaries [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier 1, Capital Required for Capital Adequacy	$ 1,665,912	$ 1,665,912		$ 1,383,475
Common Equity Tier 1, Capital Required for Capital Adequacy to Risk Weighted Assets	6.38%	6.38%		5.75%
Capital Required for Capital Adequacy	$ 2,580,531	$ 2,580,531		$ 2,225,591
Capital Required for Capital Adequacy to Risk Weighted Assets	9.88%	9.88%		9.25%
Tier One Risk Based Capital Required for Capital Adequacy	$ 2,057,892	$ 2,057,892		$ 1,744,382
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	7.88%	7.88%		7.25%
Tier One Leverage Capital Required for Capital Adequacy	$ 1,037,796	$ 1,037,796		$ 1,002,144
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	4.00%	4.00%		4.00%
Advanced Approach, Phased-In [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier 1, Capital Required for Capital Adequacy	$ 1,830,712	$ 1,830,712		$ 1,685,464
Common Equity Tier 1, Capital Required for Capital Adequacy to Risk Weighted Assets	7.00%	7.00%		7.00%
Capital Required for Capital Adequacy	$ 2,746,067	$ 2,746,067		$ 2,528,196
Capital Required for Capital Adequacy to Risk Weighted Assets	10.50%	10.50%		10.50%
Tier One Risk Based Capital Required for Capital Adequacy	$ 2,223,007	$ 2,223,007		$ 2,046,635
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	8.50%	8.50%		8.50%
Tier One Leverage Capital Required for Capital Adequacy	$ 1,038,268	$ 1,038,268		$ 1,002,494
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	4.00%	4.00%		4.00%
Advanced Approach, Phased-In [Member] | Subsidiaries [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier 1, Capital Required for Capital Adequacy	$ 1,829,237	$ 1,829,237		$ 1,684,231
Common Equity Tier 1, Capital Required for Capital Adequacy to Risk Weighted Assets	7.00%	7.00%		7.00%
Capital Required for Capital Adequacy	$ 2,743,856	$ 2,743,856		$ 2,526,347
Capital Required for Capital Adequacy to Risk Weighted Assets	10.50%	10.50%		10.50%
Tier One Risk Based Capital Required for Capital Adequacy	$ 2,221,217	$ 2,221,217		$ 2,045,138
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	8.50%	8.50%		8.50%
Tier One Leverage Capital Required for Capital Adequacy	$ 1,037,796	$ 1,037,796		$ 1,002,144
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	4.00%	4.00%		4.00%

STOCK-BASED COMPENSATION (Detai

STOCK-BASED COMPENSATION (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Restricted stock units, additional disclosures
Compensation expense	$ 4,436	$ 6,067	$ 15,633	$ 15,021
Unrecognized compensation expense related to unvested stock-settled awards	17,487		$ 17,487
Weighted average period over which expense is expected to be recognized, in years			2 years 9 months
SARs
Restricted stock units, additional disclosures
Compensation expense	19	64	$ 112	210
RSUs
Restricted stock units, additional disclosures
Compensation expense	2,261	2,184	6,235	5,491
Restricted stock
Restricted stock units, additional disclosures
Compensation expense	12	8	36	16
Cash-settled performance units
Restricted stock units, additional disclosures
Compensation expense	$ 2,144	$ 3,811	$ 9,250	$ 9,304
2015 Long-Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock shares that can be issued for compensation under the Plan	2,550,000		2,550,000

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($) $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Tax Cuts And Jobs Act Of 2017, change in tax rate, income tax expense (benefit)			$ 17.6
U.S. statutory rate	21.00%	35.00%
State taxes	1.00%	1.00%
Non-deductible expenses	1.00%	0.00%
Non-taxable income	(1.00%)	(1.00%)
Other	(1.00%)	(1.00%)
Effective tax rate	21.00%	34.00%

FAIR VALUE DISCLOSURES (Assets

FAIR VALUE DISCLOSURES (Assets and Liabilities) (Details) - USD ($)		Sep. 30, 2018		Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value		$ 117,389,000		$ 23,511,000
Loans held for sale		1,651,930,000		1,007,695,000
OREO	[1],[2]	79,000		11,700,000
Derivative assets		35,781,000		16,719,000
Derivative liabilities		27,381,000		17,377,000
Tax-exempt asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	[3]	93,369,000
Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	[3]	7,709,000		10,945,000
Fair value measurements, recurring basis | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	[4]	0		0
Derivative assets	[4]	0		0
Derivative liabilities	[4]	0		0
Non-qualified deferred compensation plan liabilities		10,467,000	[4]	5,587,000	[5]
Fair value measurements, recurring basis | Level 1 | Tax-exempt asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	[6]	0
Fair value measurements, recurring basis | Level 1 | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	[6]	0		0
Fair value measurements, recurring basis | Level 1 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	[6],[7]	9,461,000		5,460,000
Fair value measurements, recurring basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	[4]	1,630,017,000		1,007,695,000
Derivative assets	[4]	35,781,000		16,719,000
Derivative liabilities	[4]	27,381,000		17,377,000
Non-qualified deferred compensation plan liabilities		0	[4]	0	[5]
Fair value measurements, recurring basis | Level 2 | Tax-exempt asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	[6]	0
Fair value measurements, recurring basis | Level 2 | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	[6]	7,709,000		10,945,000
Fair value measurements, recurring basis | Level 2 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	[6],[7]	6,850,000		7,106,000
Fair value measurements, recurring basis | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	[4]	21,913,000		0
Derivative assets	[4]	0		0
Derivative liabilities	[4]	0		0
Non-qualified deferred compensation plan liabilities		0	[4]	0	[5]
Fair value measurements, recurring basis | Level 3 | Tax-exempt asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	[6]	93,369,000
Fair value measurements, recurring basis | Level 3 | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	[6]	0		0
Fair value measurements, recurring basis | Level 3 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	[6],[7]	0		0
Fair value measurements, nonrecurring basis | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for investment	[1],[8]	0		0
OREO	[1],[2]	0		0
Fair value measurements, nonrecurring basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for investment	[1],[8]	0		0
OREO	[1],[2]	0		0
Fair value measurements, nonrecurring basis | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for investment	[1],[8]	19,823,000		21,216,000
OREO	[1],[2]	$ 79,000		$ 11,742,000
[1]	Loans held for investment and OREO are measured on a nonrecurring basis, generally annually or more often as warranted by market and economic conditions.
[2]	OREO is transferred from loans to OREO at fair value less selling costs.
[3]	Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without prepayment penalties.
[4]	Derivative assets and liabilities are measured at fair value on a recurring basis, generally quarterly.
[5]	Non-qualified deferred compensation plan liabilities represent the fair value of the obligation to the employee, which corresponds to the fair value of the invested assets, and are measured at fair value on a recurring basis, generally monthly.
[6]	Securities are measured at fair value on a recurring basis, generally monthly
[7]	Equity securities consist of Community Reinvestment Act funds and investments related to our non-qualified deferred compensation plan.
[8]	Includes impaired loans that have been measured for impairment at the fair value of the loan’s collateral.

FAIR VALUE DISCLOSURES (Financi

FAIR VALUE DISCLOSURES (Financial Instruments) (Details)		3 Months Ended	9 Months Ended
		Sep. 30, 2018USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Dec. 31, 2017USD ($)
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Balance at Beginning of Period			$ 1,007,695,000
Balance at End of Period		$ 1,651,930,000	1,651,930,000
OREO	[1],[2]			$ 79,000		$ 11,700,000
Real Estate Owned, Valuation Allowance						0
Estimated Fair Value				117,389,000		23,511,000
Loans held for sale		1,651,930,000	1,007,695,000	1,651,930,000		1,007,695,000
Derivative assets				35,781,000		16,719,000
Senior Notes				281,677,000		281,406,000
Derivative liabilities				27,381,000		17,377,000
Level 1 | Carrying amount
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Cash and cash equivalents				2,785,051,000		2,905,591,000
Estimated Fair Value				9,461,000		5,460,000
Level 1 | Estimated fair value
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Cash and cash equivalents				2,785,051,000		2,905,591,000
Estimated Fair Value				9,461,000		5,460,000
Level 1 | Fair value measurements, recurring basis
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Balance at Beginning of Period	[3]		0
Balance at End of Period	[3]	0	0
Loans held for sale	[3]	0	0	0		0
Derivative assets	[3]			0		0
Derivative liabilities	[3]			0		0
Level 1 | Fair value measurements, nonrecurring basis
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
OREO	[1],[2]			0		0
Loans held for investment, net	[1],[4]			0		0
Level 2 | Carrying amount
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Balance at Beginning of Period			1,011,004,000
Balance at End of Period		1,630,017,000	1,630,017,000
Estimated Fair Value				14,559,000		18,051,000
Loans held for sale		1,630,017,000	1,011,004,000	1,630,017,000		1,011,004,000
Derivative assets				35,781,000		16,719,000
Federal funds purchased				475,842,000		359,338,000
Customer repurchase agreements				10,976,000		5,702,000
Other borrowings				3,200,000,000		2,800,000,000
Senior Notes				281,677,000		281,406,000
Derivative liabilities				27,381,000		17,377,000
Level 2 | Estimated fair value
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Balance at Beginning of Period			1,011,004,000
Balance at End of Period		1,630,017,000	1,630,017,000
Estimated Fair Value				14,559,000		18,051,000
Loans held for sale		1,630,017,000	1,011,004,000	1,630,017,000		1,011,004,000
Derivative assets				35,781,000		16,719,000
Federal funds purchased				475,842,000		359,338,000
Customer repurchase agreements				10,976,000		5,702,000
Other borrowings				3,200,000,000		2,800,000,000
Senior Notes				282,247,000		285,485,000
Derivative liabilities				27,381,000		17,377,000
Level 2 | Fair value measurements, recurring basis
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Balance at Beginning of Period	[3]		1,007,695,000
Balance at End of Period	[3]	1,630,017,000	1,630,017,000
Loans held for sale	[3]	1,630,017,000	1,007,695,000	1,630,017,000		1,007,695,000
Derivative assets	[3]			35,781,000		16,719,000
Derivative liabilities	[3]			27,381,000		17,377,000
Level 2 | Fair value measurements, nonrecurring basis
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
OREO	[1],[2]			0		0
Loans held for investment, net	[1],[4]			0		0
Level 3 | Carrying amount
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Balance at Beginning of Period			0
Balance at End of Period		21,913,000	21,913,000
Estimated Fair Value				93,369,000		0
Loans held for sale		21,913,000	0	21,913,000		0
Loans held for investment, net				21,857,019,000		20,489,757,000
Deposits				20,385,637,000		19,123,180,000
Trust preferred subordinated debentures				113,406,000		113,406,000
Level 3 | Estimated fair value
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Balance at Beginning of Period			0
Balance at End of Period		21,913,000	21,913,000
Estimated Fair Value				93,369,000		0
Loans held for sale		21,913,000	0	21,913,000		0
Loans held for investment, net				21,843,389,000		20,480,802,000
Deposits				20,386,435,000		19,124,121,000
Trust preferred subordinated debentures				113,406,000		113,406,000
Level 3 | Fair value measurements, recurring basis
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Balance at Beginning of Period	[3]		0
Balance at End of Period	[3]	21,913,000	21,913,000
Loans held for sale	[3]	21,913,000	0	21,913,000		0
Derivative assets	[3]			0		0
Derivative liabilities	[3]			0		0
Level 3 | Fair value measurements, nonrecurring basis
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Carrying value of impaired loans				28,000,000		32,200,000
Allowance allocation of impaired loans				8,200,000		11,000,000
OREO	[1],[2]			79,000		11,742,000
Loans held for investment, net	[1],[4]			19,823,000		21,216,000
Tax-exempt asset-backed securities
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Estimated Fair Value	[5]			93,369,000
Tax-exempt asset-backed securities | Level 1 | Fair value measurements, recurring basis
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Estimated Fair Value	[6]			0
Tax-exempt asset-backed securities | Level 2 | Fair value measurements, recurring basis
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Estimated Fair Value	[6]			0
Tax-exempt asset-backed securities | Level 3 | Fair value measurements, recurring basis
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Estimated Fair Value	[6]			$ 93,369,000
Tax-exempt asset-backed securities
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Fair Value Inputs, Projected Price				0.977
Tax-exempt asset-backed securities | Level 3 | Fair value measurements, recurring basis | Estimated fair value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, Fair Value Disclosure				$ 93,369,000	$ 0
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Balance at Beginning of Period			0
Purchases / Additions		95,521,000	95,521,000
Sales / Reductions		0	0
Realized		0	0
Unrealized		(2,152,000)	(2,152,000)
Balance at End of Period		93,369,000	93,369,000
Loans held for sale		93,369,000	0	$ 93,369,000		0
Loans held for sale
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Fair Value Inputs, Projected Price				0.935
Loans held for sale | Level 3 | Fair value measurements, recurring basis | Estimated fair value
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Balance at Beginning of Period		27,929,000	0
Purchases / Additions		901,000	38,430,000
Sales / Reductions		(6,948,000)	(14,936,000)
Realized		(134,000)	(66,000)
Unrealized		165,000	(1,515,000)
Balance at End of Period		21,913,000	21,913,000
Loans held for sale		$ 27,929,000	$ 0	$ 21,913,000	$ 27,929,000	$ 0
[1]	Loans held for investment and OREO are measured on a nonrecurring basis, generally annually or more often as warranted by market and economic conditions.
[2]	OREO is transferred from loans to OREO at fair value less selling costs.
[3]	Derivative assets and liabilities are measured at fair value on a recurring basis, generally quarterly.
[4]	Includes impaired loans that have been measured for impairment at the fair value of the loan’s collateral.
[5]	Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without prepayment penalties.
[6]	Securities are measured at fair value on a recurring basis, generally monthly

DERIVATIVE FINANCIAL INSTRUME_3

DERIVATIVE FINANCIAL INSTRUMENTS (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)instrument	Dec. 31, 2017USD ($)instrument
Derivatives, Fair Value [Line Items]
Asset Derivative	$ 40,015	$ 21,354
Liability Derivative	31,615	22,012
Offsetting derivative asset	(4,234)	(4,635)
Offsetting derivative liability	(4,234)	(4,635)
Derivative asset, net	35,781	16,719
Derivative liability, net	$ 27,381	17,377
Description of credit risk exposure on interest rate swaps and caps	Our credit exposure on derivative instruments is limited to the net favorable value and interest payments by each counterparty. In some cases collateral may be required from the counterparties involved if the net value of the derivative instruments exceeds a nominal amount
Credit exposure relating to interest rate swaps and caps	$ 20,900	16,700
Cash collateral pledge for derivatives	740	15,200
Interest-bearing deposits
Derivatives, Fair Value [Line Items]
Cash collateral pledge for derivatives		14,000
Accrued interest receivable and other assets
Derivatives, Fair Value [Line Items]
Cash collateral pledge for derivatives		$ 1,200
Interest-bearing Deposit Liability
Derivatives, Fair Value [Line Items]
Cash collateral pledge for derivatives	$ 17,900
Commercial loan/lease interest rate swaps | Non-hedging interest rate derivatives/swaps | Commercial loan/lease | Weighted-average interest rate received
Derivatives, Fair Value [Line Items]
Weighted-average interest rate received and paid	3.92%	3.59%
Commercial loan/lease interest rate swaps | Non-hedging interest rate derivatives/swaps | Commercial loan/lease | Weighted-average interest rate paid
Derivatives, Fair Value [Line Items]
Weighted-average interest rate received and paid	4.17%	4.34%
Commercial loan/lease interest rate caps
Derivatives, Fair Value [Line Items]
Weighted-average interest rate received and paid	3.17%	2.40%
Risk Participation Agreement - Participant Bank [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	$ 133,100	$ 157,100
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 120	$ 221
Derivative, number of instruments held | instrument	14	15
Risk Participation Agreements - Lead Bank [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	$ 122,400	$ 86,300
Derivative, number of instruments held | instrument	10	10
Financial institution counterparties: | Commercial loan/lease interest rate swaps | Non-hedging interest rate derivatives/swaps | Commercial loan/lease
Derivatives, Fair Value [Line Items]
Notional Amount	$ 1,593,483	$ 1,393,764
Asset Derivative	21,796	4,736
Liability Derivative	4,691	15,482
Financial institution counterparties: | Commercial loan/lease interest rate caps | Non-hedging interest rate derivatives/swaps | Commercial loan/lease
Derivatives, Fair Value [Line Items]
Notional Amount	567,490	242,700
Asset Derivative	2,525	421
Liability Derivative	17	7
Financial institution counterparties: | Foreign Exchange Forward [Member] | Non-hedging interest rate derivatives/swaps | Commercial loan/lease
Derivatives, Fair Value [Line Items]
Notional Amount	50,975	2,466
Asset Derivative	2,441	4
Liability Derivative	0	69
Customer counterparties: | Commercial loan/lease interest rate swaps | Non-hedging interest rate derivatives/swaps | Commercial loan/lease
Derivatives, Fair Value [Line Items]
Notional Amount	1,593,483	1,393,764
Asset Derivative	4,691	15,482
Liability Derivative	21,796	4,736
Customer counterparties: | Commercial loan/lease interest rate caps | Non-hedging interest rate derivatives/swaps | Commercial loan/lease
Derivatives, Fair Value [Line Items]
Notional Amount	567,490	242,700
Asset Derivative	17	7
Liability Derivative	2,525	421
Customer counterparties: | Foreign Exchange Forward [Member] | Non-hedging interest rate derivatives/swaps | Commercial loan/lease
Derivatives, Fair Value [Line Items]
Notional Amount	50,975	2,466
Asset Derivative	0	69
Liability Derivative	2,441	4
Loan purchase commitments | Interest rate derivative | Economic hedging interest rate derivatives
Derivatives, Fair Value [Line Items]
Asset Derivative	1,104	635
Liability Derivative	81	190
Forward sales commitments | Interest rate derivative | Economic hedging interest rate derivatives
Derivatives, Fair Value [Line Items]
Asset Derivative	7,441	0
Liability Derivative	64	1,103
Loan Purchase Commitments [Member] | Interest rate derivative | Non-hedging interest rate derivatives/swaps
Derivatives, Fair Value [Line Items]
Notional Amount	308,933	253,815
Forward Contracts [Member] | Interest rate derivative | Non-hedging interest rate derivatives/swaps
Derivatives, Fair Value [Line Items]
Notional Amount	$ 1,851,500	$ 1,086,224