Texas Capital Bancshares (TCBI) 10-K 14 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Feb. 13, 2019	Jun. 29, 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-K
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	FY
Amendment Flag	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		50,239,639
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 4,567,174,000

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets
Cash and due from banks	$ 214,191	$ 178,010
Interest-bearing deposits in other banks	2,815,684	2,697,581
Federal funds sold and securities purchased under resale agreements	50,190	30,000
Investment securities	120,216	23,511
Loans held for sale ($1,969.2 million and $1,007.7 million at December 2018 and 2017, respectively, at fair value)	1,969,474	1,011,004
Loans held for investment, mortgage finance	5,877,524	5,308,160
Loans held for investment (net of unearned income)	16,690,550	15,366,252
Less: Allowance for loan losses	(191,522)	(184,655)
Loans held for investment, net	22,376,552	20,489,757
Mortgage servicing rights, net	42,474	85,327
Premises and equipment, net	23,802	25,176
Accrued interest receivable and other assets	626,614	516,239
Goodwill and intangible assets, net	18,570	19,040
Total assets	28,257,767	25,075,645
Deposits:
Non-interest-bearing	7,317,161	7,812,660
Interest-bearing	13,288,952	11,310,520
Total deposits	20,606,113	19,123,180
Accrued interest payable	20,675	7,680
Other liabilities	194,238	182,212
Federal funds purchased and repurchase agreements	641,174	365,040
Other borrowings	3,900,000	2,800,000
Subordinated notes, net	281,767	281,406
Trust preferred subordinated debentures	113,406	113,406
Total liabilities	25,757,373	22,872,924
Comprehensive income:
Preferred stock, $.01 par value, $1,000 liquidation value: Authorized shares - 10,000,000; Issued shares - 6,000,000 shares issued at December 31, 2018 and 2017	150,000	150,000
Common stock, $.01 par value: Authorized shares - 100,000,000; Issued shares - 45,735,424 and 41,036,787 at December 31, 2018 and 2017, respectively	502	496
Additional paid-in capital	967,890	961,305
Retained earnings	1,381,492	1,090,500
Treasury stock (shares at cost: 417 at December 31, 2018 and 2017)	(8)	(8)
Accumulated other comprehensive income, net of taxes	518	428
Total stockholders’ equity	2,500,394	2,202,721
Total liabilities and stockholders’ equity	$ 28,257,767	$ 25,075,645

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Loans held for sale ($1,007.7 million and $968.9 million at December 2017 and 2016, respectively, at fair value)	$ 1,969,200,000	$ 1,007,700,000
Preferred stock, Liquidation value	$ 1,000	$ 1,000
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	50,201,127	49,643,761
Treasury stock, shares	417	417

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME AND OTHER COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest income
Interest and fees on loans	$ 1,124,970	$ 846,292	$ 684,582
Investment securities	2,834	1,066	967
Federal funds sold and securities purchased under resale agreements	3,792	2,542	1,547
Interest-bearing deposits in other banks	32,597	29,399	16,312
Total interest income	1,164,193	879,299	703,408
Interest expense
Deposits	185,116	79,886	37,175
Federal funds purchased	6,531	2,592	518
Other borrowings	36,207	15,137	6,128
Subordinated notes	16,764	16,764	16,764
Trust preferred subordinated debentures	4,715	3,592	3,009
Total interest expense	249,333	117,971	63,594
Net interest income	914,860	761,328	639,814
Provision for credit losses	87,000	44,000	77,000
Net interest income after provision for credit losses	827,860	717,328	562,814
Non-interest income
Service charges on deposit accounts	12,787	12,432	10,341
Wealth management and trust fee income	8,148	6,153	4,268
Brokered loan fees	22,532	23,331	25,339
Servicing income	18,307	15,657	1,715
Swap fees	5,625	3,990	2,866
Gain/(Loss) on sale of loans held for sale	(15,934)	(2,387)	2,547
Other	26,559	15,080	13,704
Total non-interest income	78,024	74,256	60,780
Non-interest expense
Salaries and employee benefits	291,768	264,231	228,985
Net occupancy expense	30,342	25,811	23,221
Marketing	39,335	26,787	17,303
Legal and professional	42,990	29,731	23,326
Communications and technology	30,056	31,004	25,562
FDIC insurance assessment	24,307	23,510	24,440
Servicing related expenses	14,934	15,506	1,703
Allowance and other carrying costs for other real estate owned	474	6,437	824
Other	50,890	42,859	37,033
Total non-interest expense	525,096	465,876	382,397
Income before income taxes	380,788	325,708	241,197
Income tax expense	79,964	128,645	86,078
Net income	300,824	197,063	155,119
Preferred stock dividends	(9,750)	(9,750)	(9,750)
Net income available to common stockholders	291,074	187,313	145,369
Other comprehensive income (loss)
Change in unrealized gain (loss) on available-for-sale debt securities arising during period, before tax	7	19	(467)
Income tax expense (benefit) related to unrealized loss on available-for-sale debt securities	1	6	(164)
Other comprehensive income (loss), net of tax	6	13	(303)
Comprehensive income	$ 300,830	$ 197,076	$ 154,816
Basic earnings per common share
Basic earnings per common share	$ 5.83	$ 3.78	$ 3.14
Diluted earnings per common share
Diluted earnings per common share	$ 5.79	$ 3.73	$ 3.11

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
Beginning balance - Shares at Dec. 31, 2015		6,000,000	45,874,224			417
Beginning balance - Amount at Dec. 31, 2015	$ 1,623,533	$ 150,000	$ 459	$ 714,546	$ 757,818	$ (8)	$ 718
Comprehensive income:
Net income	155,119				155,119
Change in unrealized gain (loss) on available-for-sale securities, net of taxes	(303)						(303)
Comprehensive income	154,816
Employee Service Share-based Compensation, Tax Benefit from Exercise of Stock Options	1,879			1,879
Stock-based compensation expense recognized in earnings	5,093			5,093
Preferred stock dividends	(9,750)				(9,750)
Issuance of stock related to stock-based awards - Shares			172,459
Issuance of stock related to stock-based awards - Amount	(2,481)		$ 1	(2,482)
Issuance of stock - Shares			3,450,000
Issuance of stock - Amount	236,467		$ 35	236,432
Ending balance - Amount at Dec. 31, 2016	2,009,557	$ 150,000	$ 495	955,468	903,187	$ (8)	415
Ending balance - Shares at Dec. 31, 2016		6,000,000	49,504,079			417
Comprehensive income:
Stock Issued During Period, Shares, Other			7,396
Stock Issued During Period, Value, Other	0		$ 0	0
Net income	197,063				197,063
Change in unrealized gain (loss) on available-for-sale securities, net of taxes	13						13
Comprehensive income	197,076
Stock-based compensation expense recognized in earnings	8,079			8,079
Preferred stock dividends	(9,750)				(9,750)
Issuance of stock related to stock-based awards - Shares			106,087
Issuance of stock related to stock-based awards - Amount	(2,241)		$ 1	(2,242)
Ending balance - Amount at Dec. 31, 2017	2,202,721	$ 150,000	$ 496	961,305	1,090,500	$ (8)	428
Ending balance - Shares at Dec. 31, 2017		6,000,000	49,643,761			417
Comprehensive income:
Stock Issued During Period, Shares, Other			33,595
Stock Issued During Period, Value, Other	0		$ 0	0
Net income	300,824				300,824
Change in unrealized gain (loss) on available-for-sale securities, net of taxes	6						6
Comprehensive income	300,830
Stock-based compensation expense recognized in earnings	8,973			8,973
Preferred stock dividends	(9,750)				(9,750)
Issuance of stock related to stock-based awards - Shares			120,242
Issuance of stock related to stock-based awards - Amount	(2,382)		$ 1	(2,383)
Ending balance - Amount at Dec. 31, 2018	$ 2,500,394	$ 150,000	$ 502	967,890	$ 1,381,492	$ (8)	$ 518
Ending balance - Shares at Dec. 31, 2018		6,000,000	50,201,127			417
Comprehensive income:
Stock Issued During Period, Shares, Other			437,124
Stock Issued During Period, Value, Other			$ 5	$ (5)

CONSOLIDATED STATEMENTS OF ST_2

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Stockholders' Equity [Abstract]
Income tax expense (benefit) related to unrealized loss on available-for-sale securities	$ 1	$ 6	$ (164)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities
Net income	$ 300,824	$ 197,063	$ 155,119
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	87,000	44,000	77,000
Deferred tax expense (benefit)	(6,400)	31,276	(2,946)
Depreciation and amortization	32,022	27,871	21,814
Net (gain)/loss on sale of loans held for sale	15,934	2,387	(2,547)
Increase (decrease) in valuation allowance on mortgage servicing rights	(2,823)	2,823	0
Stock-based compensation expense	16,938	22,019	13,578
Excess tax benefits from stock-based compensation arrangements	0	0	(2,013)
Purchases and originations of loans held for sale	(6,753,709)	(5,556,964)	(3,327,482)
Proceeds from sales and repayments of loans held for sale	5,759,067	5,457,117	2,405,592
Technology write-off	0	5,285	0
Other real estate owned write-down	0	6,111	0
Changes in operating assets and liabilities:
Accrued interest receivable and other assets	(123,542)	(117,116)	(61,832)
Accrued interest payable and other liabilities	(5,026)	10,289	(2,576)
Net cash provided by (used in) operating activities	(679,715)	132,161	(726,293)
Investing activities
Purchases of available-for-sale investment securities	(101,558)	(97,776)	(1,760)
Maturities and calls of available-for-sale securities	0	94,775	555
Principal payments received on available-for-sale securities	3,426	4,383	5,856
Originations of mortgage finance loans	(99,151,237)	(86,931,566)	(100,574,326)
Proceeds from pay-offs of mortgage finance loans	98,581,873	86,120,744	101,043,264
Proceeds from sale of mortgage servicing rights	(70,824)	0	0
Net increase in loans held for investment, excluding mortgage finance loans	(1,402,068)	(2,395,063)	(1,321,733)
Purchase of premises and equipment, net	(7,651)	(12,265)	(2,176)
Proceeds from sale of other real estate owned, net	13,645	1,023	110
Net cash used in investing activities	(1,992,746)	(3,215,745)	(850,210)
Financing activities
Net increase in deposits	1,482,933	2,106,349	1,932,212
Costs from issuance of stock related to stock-based awards and warrants	(2,382)	(2,241)	(2,481)
Net proceeds from issuance of common stock	0	0	236,467
Preferred dividends paid	(9,750)	(9,750)	(9,750)
Net increase in other borrowings	1,100,000	800,000	500,000
Excess tax benefits from stock-based compensation arrangements	0	0	2,013
Net increase (decrease) in Federal funds purchased and repurchase agreements	276,134	255,465	(33,476)
Net cash provided by financing activities	2,846,935	3,149,823	2,624,985
Net increase in cash and cash equivalents	174,474	66,239	1,048,482
Cash and cash equivalents at beginning of period	2,905,591	2,839,352	1,790,870
Cash and cash equivalents at end of period	3,080,065	2,905,591	2,839,352
Supplemental disclosures of cash flow information:
Cash paid during the period for interest	236,338	115,789	63,193
Cash paid during the period for income taxes	75,405	103,871	88,262
Transfers from loans/leases to other real estate owned and other repossessed assets	$ 0	$ 0	$ 18,822

Operations and Summary of Signi

Operations and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 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 or national clientele of commercial borrowers. We are primarily a secured lender, with the majority of our loans held for investment, excluding mortgage finance loans and other national lines of business, being made to businesses headquartered or with operations in Texas. Our national lines of business provide specialized leading products 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. 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 financial instruments and the status of contingencies are particularly susceptible to significant change. Basic and Diluted Earnings Per Common Share Basic earnings per common share is based on net income available to common stockholders divided by the weighted-average number of common shares outstanding during the period excluding non-vested stock. Diluted earnings per common share include the dilutive effect of stock options and non-vested stock awards granted using the treasury stock method. A reconciliation of the weighted-average shares used in calculating basic earnings per common share and the weighted average common shares used in calculating diluted earnings per common share for the reported periods is provided in Note 2 — Earnings Per Share. Accumulated Other Comprehensive Income Unrealized gains or losses on our available-for-sale debt securities (after applicable income tax expense or benefit) are included in accumulated other comprehensive income (loss), net ("AOCI"). AOCI is reported in the accompanying consolidated statements of stockholders’ equity and consolidated statements of income and other comprehensive income. GAAP does not permit the adjustment of tax amounts in AOCI for changes in tax rates, the effects become stranded in AOCI. 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 "Tax Act") are reclassified from AOCI to retained earnings in accordance with our early adoption of ASU 2018-02 Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income." Cash and Cash Equivalents Cash equivalents include amounts due from banks, interest-bearing deposits in other banks, Federal funds sold and securities purchased under resale agreements. 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 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. The cost of securities sold is based on the specific identification method. All debt securities are available-for-sale as of December 31, 2018 and 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 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. Loans Loans Held for Sale Through our mortgage correspondent aggregation ("MCA") program, 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 third parties such as Ginnie Mae or to GSEs such as Fannie Mae or Freddie Mac. In some cases, we retain the mortgage servicing rights. Once purchased, these loans are classified as held for sale and are carried at fair value pursuant to our election of the fair value option in accordance with Accounting Standards Codification ("ASC") 825, Financial Instruments . At the commitment date, we enter into a corresponding forward sale commitment with a third party, typically Ginnie Mae or a GSE, to deliver the loans within a specified timeframe. The estimated gain/loss for the entire transaction (from initial purchase commitment to final delivery of loans) is recorded as an asset or liability. The fair value of loans held for sale is derived from observable current market prices, when available, and includes the fair value of the mortgage servicing rights. Adjustments to reflect unrealized gains and losses resulting from changes in fair value and realized gains and losses upon ultimate sale of the loans are classified as gain/(loss) on sale of loans held for sale in the consolidated statements of income and other comprehensive income. 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 managed through forward sales contracts, which set the price for loans that will be delivered in the next 60 to 90 days. Pursuant to Ginnie Mae servicing guidelines, we have the unilateral right, but not the obligation, to repurchase certain delinquent loans securitized in Ginnie Mae pools, if they meet defined delinquent loan criteria. Once the delinquency criteria have been met, and regardless of whether the repurchase option has been exercised, we account for these loans as if they had been repurchased and recognize the loans and a corresponding liability as held for sale and other liabilities, respectively, in the consolidated balance sheets. If the loans are actually repurchased, the liability is cash settled and the loans continue to be reported as held for sale. As an approved lender, we may collect losses incurred on repurchased loans through a claims process with the government agency. From time to time we hold for sale the guaranteed portion of Small Business Administration 7(a) loans, which are carried at lower of cost or market. Loans Held for Investment Loans held for investment (including financing leases) are stated at the amount of unpaid principal reduced by deferred income (net of costs). Interest on loans is recognized using the simple-interest method on the daily balances of the principal amounts outstanding. Loan origination fees, net of direct loan origination costs, and commitment fees, are deferred and amortized as an adjustment to yield over the life of the loan, or over the commitment period, as applicable. 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 loan agreement. Reserves on impaired loans are measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate or the fair value of the underlying collateral, less cost to sell. Impaired loans, or portions thereof, are charged off when a confirmed loss exists. 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 contractual interest rate, extension of the maturity date at a contractual interest rate lower than the current rate for new debt with similar risk, or a reduction of the face amount of debt, or forgiveness of either principal or accrued interest. A loan continues to qualify as restructured until a consistent payment history or change in borrower’s financial condition has been evidenced, generally 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 modified terms in calendar years after the year of the restructure. The accrual of interest on loans is discontinued when there is a clear indication that the borrower’s cash flow may not be sufficient to meet payments as they become due, which is generally when a loan is 90 days past due. When a loan is placed on non-accrual status, all previously accrued and unpaid interest is reversed. Interest income is subsequently recognized on a cash basis as long as the remaining book balance of the asset is deemed to be collectible. If collectability is questionable, then cash payments are applied to principal. 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. Loans held for investment includes legal ownership interests in mortgage loans that we purchase through our mortgage warehouse lending division. The ownership interests are purchased from unaffiliated mortgage originators who are seeking additional funding through sale of the undivided ownership interests to facilitate their ability to originate loans. The mortgage originator has no obligation to offer and we have no obligation to purchase these interests. The originator closes mortgage loans consistent with underwriting standards established by approved investors, and, at the time of the sale to the investor, our ownership interest and that of the originator are delivered by us to the investor selected by the originator and approved by us. We typically purchase up to a 99% ownership interest in each mortgage with the originator owning the remaining percentage. These mortgage ownership interests are generally held by us for a period of less than 30 days and more typically 10-20 days. Because of conditions in agreements with originators designed to reduce transaction risks, under ASC 860, Transfers and Servicing of Financial Assets (“ASC 860”), the ownership interests do not qualify as participating interests. Under ASC 860, the ownership interests are deemed to be loans to the originators and payments we receive from investors are deemed to be payments made by or on behalf of the originator to repay the loan deemed made to the originator. Because we have an actual, legal ownership interest in the underlying residential mortgage loan, these interests are extensions of credit to the originators that are secured by the mortgage loans as collateral. Due to market conditions or events of default by the investor or the originator, we could be required to purchase the remaining interests in the mortgage loans and hold them beyond the expected 10-20 days. Mortgage loans acquired under these conditions would require mark-to-market adjustments to income and could require future allocations of the allowance for loan losses or be subject to charge off in the event the loans become impaired. Mortgage loan interests purchased and disposed of as expected receive no allocation of the allowance for loan losses due to the minimal loss experience with these assets. Allowance for Loan Losses The allowance for loan losses is comprised of general reserves, specific reserves for impaired loans and an additional qualitative reserve, all based on our estimate of losses inherent in the portfolio at the balance sheet date, but not yet identified with specified loans. In order to determine the allowance for loan losses, all loans are assigned a credit grade. Loan commitments graded substandard or worse and greater than $500,000 are specifically reviewed for loss potential. Loans deemed to be impaired, as well as restructured loans and loans formerly reported as restructured, are assigned a specific reserve based on the losses expected to be realized from those loans. For purposes of determining the general reserve, the remainder of the portfolio is segregated by product types to recognize differing risk profiles among portfolio segments, and then further segregated by credit grades. Each credit grade is assigned a risk factor, or reserve allocation percentage. These risk factors are multiplied by the outstanding principal balance of each loan and risk-weighted by product type to calculate a required reserve. A similar process is employed to calculate a reserve assigned to off-balance sheet commitments, specifically unfunded loan commitments and letters of credit, and any needed reserve is recorded in other liabilities. Even though portions of the allowance may be allocated to specific loans, the entire allowance is available for any credit that, in management’s judgment, should be charged off. We have several pass credit grades that are assigned to loans based on varying levels of risk, ranging from credits that are secured by cash or marketable securities, to watch credits which have all the characteristics of an acceptable credit risk but warrant more than the normal level of monitoring. Within our criticized/classified credit grades are special mention, substandard, and doubtful. Special mention loans are those that are currently protected by the sound worth and paying capacity of the borrower, but that are potentially weak and constitute an additional credit risk. These loans have the potential to deteriorate to a substandard grade due to the existence of financial or administrative deficiencies. Substandard loans have a well-defined weakness or weaknesses that jeopardize the liquidation of the debt. They are characterized by the distinct possibility that we will sustain some loss if the deficiencies are not corrected. Some substandard loans are inappropriately protected by sound worth and paying capacity of the borrower and of the collateral pledged and may be considered impaired. Substandard loans can be accruing or can be on non-accrual depending on the circumstances of the individual loans. Loans classified as doubtful have all the weaknesses inherent in substandard loans with the added characteristics that the weaknesses make collection or liquidation in full highly questionable and improbable. The possibility of loss is extremely high. All doubtful loans are on non-accrual. The allowance allocation percentages assigned to each credit grade have been developed based primarily on an analysis of our historical loss rates. The level of the allowance reflects management’s continuing evaluation of conditions likely to impact the amount of losses expected to be incurred in the Bank’s loan portfolio. Such conditions include, without limitation, credit quality indicators such as amounts and percentages of loans classified as past due, criticized and non-performing, conditions internal to the Bank such as the skill and experience of lending and credit personnel and effectiveness of credit review processes, the rate of portfolio growth, the extent of hold limits and loan concentrations, such as loans to specific borrowers, loans to groups of affiliated borrowers, loans to borrowers in defined industry groups and loans to borrowers, and collateral, in defined geographic locations. Conditions external to the Bank that may impact incurred losses that are also considered by management in the evaluation of the allowance include the general health of the national economy and regional economies where the Bank operates, international economic conditions, domestic and international political events that may impact the Bank’s loan portfolio, regulatory developments deemed relevant to risk assessment and classification of credits and circumstances that may have negative consequences for industries or specific borrowers where the Bank has exposure. Management’s assessment of the allowance begins with a review of historical credit loss experience as a baseline before consideration of current environmental issues both internal and external to the Bank that might reasonably cause the measure of incurred loss to differ from historical experience. The Bank’s allowance methodology employs a loss migration technique to determine historical loss percentages applicable to all defined credit risk grades. The methodology also calculates historical loss percentages by portfolio segment and computes segment weights as a measure of the relative risk of loans in each segment compared to the entire portfolio. These processes allow for a continuous review of not only absolute historical loss percentages but also an assessment of credit risk grade migration, positive and negative, and changes in portfolio composition as defined by portfolio segment. Management has identified certain measures that are believed to offer guidance as leading, concurrent and trailing indicators respectively of general economic health that in turn are thought to be relevant to the measure of incurred loss in the Bank’s loan portfolio. These together with other internal and external risk elements have been individually quantified and collectively compiled into an aggregate range of adjustment from which management selects a single qualitative factor ("Q Factor"). This Q Factor is added or subtracted from historical loss rates, as relevant, to compute an appropriate reserve based upon actual portfolio composition as defined by portfolio segment and credit risk grade composition. By compiling identified risk elements into a range of possible adjustment and selection by management of a single factor from the range, management minimizes the risk of over-adjusting historical loss rates for changes in multiple contributing elements that may individually be signaling the same change in incurred loss. The specific Q Factor adjustment and application of any management overlay to model calculated segment weights reflects management’s determination that the allowance model is calculating an appropriate level of the allowance in the context of all known loan portfolio quality and concentration issues as well as other environmental factors that are reasonably believed to cause the measure of incurred loss, inclusive of unidentified losses inherent in the current portfolio, to differ from historical experience. Because credit risk grade migration, both positive and negative, can significantly trail triggering events such as change in economic conditions, commodity prices or interest rates or changes in collateral values or changes in regulatory interpretation or application of laws or standards impacting the Bank’s lending activities, management’s interpretation of the collective impact of all such issues on incurred loss guides management’s selection of an appropriate Q Factor adjustment. The additional qualitative reserve component of the allowance that is not derived by the allowance allocation percentages compensates for the uncertainty and complexity in estimating loan and lease losses associated with circumstances or events that are out of the ordinary, not predictable in amount or frequency or not reasonably correlated with either past experience and/or general economic conditions. Examples of such events include natural disasters such as hurricanes and borrower fraud through act or omission in delivery of accurate financial reporting or certification of collateral value. These situations, while not common, do not necessarily correlate well 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 such unpredictable events. The methodology used in the periodic review of the appropriateness of the allowance, which is performed at least quarterly, is designed to be dynamic and responsive to changes in portfolio credit quality. Changes are reflected in the general allowance, in specific reserves as the collectability of classified loans is evaluated with new information and in the additional qualitative reserve. As our portfolio has matured, historical loss ratios have been closely monitored. Our reserve appropriateness relies primarily on our loss history, supplemented by our additional qualitative reserve. The review of the appropriateness of the allowance is performed by executive management and presented to the audit and risk committees of our board of directors for their review. The committees report to the board as part of the board's review on a quarterly basis of the Company's consolidated financial statements. Other Real Estate Owned Other real estate owned (“OREO”), which is included in other assets on the consolidated balance sheet, consists of real estate that has been foreclosed. 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 through a charge to the allowance for loan losses, if necessary. Subsequent write-downs required for declines in value are recorded through a valuation allowance, or taken directly to the asset, and are recorded in allowance and other carrying costs for OREO in the consolidated statements of income and other comprehensive income. Gains or losses on sale of OREO are recorded in other non-interest income in the consolidated statements of income and other comprehensive income. Mortgage Servicing Rights, Net Mortgage servicing rights ("MSRs") are created by selling mortgage loans with servicing rights retained. We identify classes of servicing rights based upon the nature of the underlying assumptions used to value the asset along with the risks associated with the underlying asset. Based upon these criteria we have one class of MSRs, residential. MSRs are recognized based on the estimated fair value of the mortgage loans and the related servicing rights at the date of sale using values derived from a valuation model. MSRs are reported on the consolidated balance sheets at amortized cost, less a valuation allowance if the fair value of identified strata within the MSR portfolio are determined to have a fair value that is less than amortized cost. MSRs are amortized proportionally over the estimated life of the projected net servicing revenue and are periodically evaluated for impairment. Loan servicing fee income represents income earned for servicing mortgage loans owned by investors and includes mortgage servicing fees and other ancillary servicing income. Servicing fees are recorded as income when earned and are reported in non-interest income on the consolidated statements of income and other comprehensive income. MSR valuation allowance expense and servicing related expenses are recorded in servicing related expenses in the consolidated statements of income and other comprehensive income. Goodwill and Other Intangible Assets, Net Intangible assets are acquired assets that lack physical substance but can be distinguished from goodwill because of contractual or other legal rights or because the asset is capable of being sold or exchanged either on its own or in combination with a related contract, asset, or liability. Our intangible assets relate primarily to loan customer relationships purchased as part of business acquisitions. Intangible assets with definite useful lives are amortized over their estimated life. Goodwill and intangible assets are tested for impairment at least annually or whenever changes in circumstances indicate the carrying amount of the assets may not be recoverable from future undiscounted cash flows. If impaired, the assets are recorded at fair value. Premises and Equipment, Net Premises and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets. Furniture and equipment is generally depreciated over three to five years , while leasehold improvements are generally depreciated over the term of their respective lease. Gains or losses on disposals of premises and equipment are included in other non-interest income in the consolidated statements of income and other comprehensive income. Software Costs incurred in connection with development or purchase of internal use software and cloud computing arrangements, including an in-substance software license, are capitalized. Amortization is computed on a straight-line basis over the estimated useful life of the asset, which generally range from one to five years . Capitalized internal use software is included in other assets in the consolidated balance sheets. Financial Instruments with Off-Balance Sheet Risk The Company has undertaken certain guarantee obligations in the ordinary course of business which include liabilities with off-balance sheet risk. We consider the following arrangements to be guarantees: commitments to extend credit, standby letters of credit and indemnification agreements included within third party contractual arrangements. 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. 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 will include 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 actual losses experienced from actual activity. Revenue Recognition 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). Payment 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 managemen

Investment Securities

Investment Securities	12 Months Ended
	Dec. 31, 2018
Debt Securities, Available-for-sale [Abstract]
Investment Securities	Securities Available-for-Sale Debt Securities The following is a summary of available-for-sale debt securities: (in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value December 31, 2018 Available-for-sale debt securities: Residential mortgage-backed securities $ 6,874 $ 368 $ — $ 7,242 Tax-exempt asset-backed securities 95,518 286 — 95,804 $ 102,392 $ 654 $ — $ 103,046 December 31, 2017 Available-for-sale debt securities: 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 December 31, 2018 . The amortized cost and estimated fair value of available-for-sale debt securities are presented below by contractual maturity: (in thousands, except percentage data) Less Than One Year After One Through Five Years After Five Through Ten Years After Ten Years Total December 31, 2018 Available-for-sale: Residential mortgage-backed securities:(1) Amortized cost $ 3 $ 1,573 $ — $ 5,298 $ 6,874 Estimated fair value 4 1,668 — 5,570 7,242 Weighted average yield(3) 6.50 % 5.54 % — % 4.53 % 4.76 % Tax-exempt asset-backed securities:(1) Amortized Cost — — — 95,518 95,518 Estimated fair value — — — 95,804 95,804 Weighted average yield(2)(3) — % — % — % 4.25 % 4.25 % Total available-for-sale debt securities: Amortized cost $ 102,392 Estimated fair value $ 103,046 December 31, 2017 Available-for-sale: 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. Available-for-sale debt securities with carrying values of approximately $4.8 million and $1.7 million were pledged to secure certain customer repurchase agreements and deposits at December 31, 2018 . The comparative amounts at December 31, 2017 were $7.3 million and $1.6 million , respectively. Equity Securities Equity securities consist of Community Reinvestment Act funds and investments related to our non-qualified deferred compensation plan. At December 31, 2018 and December 31, 2017 , we had $17.2 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/(losses) recognized in net income on equity securities: Year Ended (in thousands) Net gains/(losses) recognized during the period $ (975 ) Less: Realized net gains/(losses) recognized during the period on equity securities sold 460 Unrealized net gains/(losses) recognized during the period on equity securities still held $ (1,435 )

Loans Held for Investment and A

Loans Held for Investment and Allowance for Loan Losses	12 Months Ended
	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract]
Loans Held for Investment and Allowance for Loan Losses	Loans Held for Investment and Allowance for Loan Losses Loans held for investment are summarized by portfolio segment as follows: December 31, (in thousands) 2018 2017 Commercial $ 10,373,288 $ 9,189,811 Mortgage finance 5,877,524 5,308,160 Construction 2,120,966 2,166,208 Real estate 3,929,117 3,794,577 Consumer 63,438 48,684 Equipment leases 312,191 264,903 Gross loans held for investment 22,676,524 20,772,343 Deferred income (net of direct origination costs) (108,450 ) (97,931 ) Allowance for loan losses (191,522 ) (184,655 ) Total loans held for investment, net $ 22,376,552 $ 20,489,757 Summary of Loan Loss Experience The following tables summarize the credit risk profile of our loans held for investment by internally assigned grades and non-accrual status: (in thousands) Commercial Mortgage Finance Construction Real Estate Consumer Equipment Leases Total December 31, 2018 Grade: Pass $ 10,034,597 $ 5,877,524 $ 2,099,955 $ 3,850,811 $ 61,815 $ 309,775 $ 22,234,477 Special mention 120,531 — 21,011 47,644 — 2,223 191,409 Substandard-accruing 140,297 — — 28,205 1,568 193 170,263 Non-accrual 77,863 — — 2,457 55 — 80,375 Total loans held for investment $ 10,373,288 $ 5,877,524 $ 2,120,966 $ 3,929,117 $ 63,438 $ 312,191 $ 22,676,524 December 31, 2017 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 allowance for loan losses is comprised of general reserves, specific reserves for impaired loans and an additional qualitative reserve all based on our estimate of losses inherent in the portfolio at the balance sheet date, but not yet identified with specified loans. For further discussion of the components of the allowance for loan losses as well as details regarding how the estimate of inherent losses is determined, refer to the Allowance for Loan Losses subheading in Note 1 - Operations and Summary of Significant Accounting Policies. We believe the allowance at December 31, 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 table details activity in the allowance for loan losses, as well as the recorded investment in loans held for investment, by portfolio segment and disaggregated on the basis of our impairment methodology. Allocation of a portion of the allowance to one category of loans does not preclude its availability to absorb losses in other categories. (in thousands) Commercial Mortgage Finance Construction Real Estate Consumer Equipment Leases Additional Qualitative Reserve Total Year ended December 31, 2018 Allowance for loan losses: Beginning balance $ 118,806 $ — $ 19,273 $ 34,287 $ 357 $ 3,542 $ 8,390 $ 184,655 Provision for loan losses 87,860 — (31 ) (1,003 ) 397 (1,427 ) (1,159 ) 84,637 Charge-offs 79,692 — — — 767 319 — 80,778 Recoveries 2,468 — — 69 438 33 — 3,008 Net charge-offs (recoveries) 77,224 — — (69 ) 329 286 — 77,770 Ending balance $ 129,442 $ — $ 19,242 $ 33,353 $ 425 $ 1,829 $ 7,231 $ 191,522 Period end allowance for loan losses allocated to: Loans individually evaluated for impairment $ 8,252 $ — $ — $ 48 $ 10 $ — $ — $ 8,310 Loans collectively evaluated for impairment 121,190 — 19,242 33,305 415 1,829 7,231 183,212 Total $ 129,442 $ — $ 19,242 $ 33,353 $ 425 $ 1,829 $ 7,231 $ 191,522 Period end loans allocated to: Loans individually evaluated for impairment $ 78,428 $ — $ — $ 8,857 $ 55 $ — $ — $ 87,340 Loans collectively evaluated for impairment 10,294,860 5,877,524 2,120,966 3,920,260 63,383 312,191 — 22,589,184 Total $ 10,373,288 $ 5,877,524 $ 2,120,966 $ 3,929,117 $ 63,438 $ 312,191 $ — $ 22,676,524 Year ended December 31, 2017 Allowance for loan losses: Beginning balance $ 128,768 $ — $ 13,144 $ 19,149 $ 241 $ 1,124 $ 5,700 $ 168,126 Provision for loan losses 19,590 — 6,084 15,353 226 2,408 2,690 46,351 Charge-offs 34,145 — 59 290 180 — — 34,674 Recoveries 4,593 — 104 75 70 10 — 4,852 Net charge-offs (recoveries) 29,552 — (45 ) 215 110 (10 ) — 29,822 Ending balance $ 118,806 $ — $ 19,273 $ 34,287 $ 357 $ 3,542 $ 8,390 $ 184,655 Period end allowance for loan losses allocated to: Loans individually evaluated for impairment $ 24,316 $ — $ — $ 101 $ — $ — $ — $ 24,417 Loans collectively evaluated for impairment 94,490 — 19,273 34,186 357 3,542 8,390 160,238 Total $ 118,806 $ — $ 19,273 $ 34,287 $ 357 $ 3,542 $ 8,390 $ 184,655 Period end loans allocated to: 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 We have traditionally maintained an additional qualitative reserve component to compensate for the uncertainty and complexity in estimating loan and lease losses associated with circumstances or events that are out of the ordinary, not predictable in amount or frequency or not reasonably correlated with other past experience and/or general economic conditions. At December 31, 2018 , the additional qualitative reserve as a percentage of loans held for investment was 0.03% compared to 0.04% at December 31, 2017 . The decline in the additional qualitative reserve at December 31, 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. The following tables detail our impaired loans held for investment by portfolio segment. In accordance with ASC 310, Receivables , we have also included all restructured and formerly restructured loans in our impaired loan totals. (in thousands) Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized December 31, 2018 With no related allowance recorded: Commercial Business loans $ 23,367 $ 55,008 $ — $ 16,426 $ 133 Energy loans 12,188 13,363 — 17,135 — Construction Market risk — — — — — Real estate Market risk — — — — — Commercial 7,388 7,388 — 3,215 — Secured by 1-4 family 1,233 1,233 — 734 — Consumer — — — — — Equipment leases — — — — — Total impaired loans with no allowance recorded $ 44,176 $ 76,992 $ — $ 37,510 $ 133 With an allowance recorded: Commercial Business loans $ 17,529 $ 17,564 $ 4,679 $ 41,307 $ — Energy loans 25,344 28,105 3,573 25,672 — Construction Market risk — — — — — Real estate Market risk — — — 49 — Commercial — — — 83 — Secured by 1-4 family 236 236 48 188 — Consumer 55 55 10 54 — Equipment leases — — — 275 — Total impaired loans with an allowance recorded $ 43,164 $ 45,960 $ 8,310 $ 67,628 $ — Combined: Commercial Business loans $ 40,896 $ 72,572 $ 4,679 $ 57,733 $ 133 Energy loans 37,532 41,468 3,573 42,807 — Construction Market risk — — — — — Real estate Market risk — — — 49 — Commercial 7,388 7,388 — 3,298 — Secured by 1-4 family 1,469 1,469 48 922 — Consumer 55 55 10 54 — Equipment leases — — — 275 — Total impaired loans $ 87,340 $ 122,952 $ 8,310 $ 105,138 $ 133 (in thousands) Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized December 31, 2017 With no related allowance recorded: Commercial Business loans $ 16,835 $ 18,257 $ — $ 22,964 $ — Energy loans 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 — — — — — Equipment 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 loans 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 — Equipment 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 loans 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 — Equipment leases — — — 14 — Total impaired loans $ 102,684 $ 117,762 $ 24,417 $ 130,777 $ 6 Average impaired loans outstanding during the years ended December 31, 2018 , 2017 and 2016 totaled $105.1 million , $130.8 million and $174.1 million , respectively. For the years ended December 31, 2018 , 2017 and 2016 , we recognized $133,000 , $6,000 and $62,000 , respectively, in interest income on non-accrual loans. Additional interest income that would have been recorded if the loans had been current during the years ended December 31, 2018 , 2017 and 2016 totaled $8.5 million , $19.0 million and $7.9 million , respectively. As of December 31, 2018 and 2017 , none of our non-accrual loans were earning interest income on a cash basis. The table below provides an age analysis of our loans held for investment: (in thousands) 30-59 Days Past Due 60-89 Days Past Due Greater Than 90 Days(1) Total Past Due Non-accrual Current Total December 31, 2018 Commercial Business loans $ 16,845 $ 13,680 $ 9,163 $ 39,688 $ 40,331 $ 8,662,285 $ 8,742,304 Energy — 1,150 — 1,150 37,532 1,592,302 1,630,984 Mortgage finance loans — — — — — 5,877,524 5,877,524 Construction Market risk — 2,551 — 2,551 — 2,028,062 2,030,613 Commercial — — — — — 64,957 64,957 Secured by 1-4 family 59 — — 59 — 25,337 25,396 Real estate Market risk 1,738 — — 1,738 — 2,786,299 2,788,037 Commercial 1,643 4,595 — 6,238 988 776,232 783,458 Secured by 1-4 family 1,484 44 190 1,718 1,469 354,435 357,622 Consumer — — — — 55 63,383 63,438 Equipment leases 256 — — 256 — 311,935 312,191 Total loans held for investment $ 22,025 $ 22,020 $ 9,353 $ 53,398 $ 80,375 $ 22,542,751 $ 22,676,524 (1) Loans past due 90 days and still accruing includes premium finance loans of $9.2 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. As of December 31, 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 December 31, 2018 and 2017 , $20.0 million and $18.8 million , respectively, met the criteria for restructured. These loans had no unfunded commitments at their respective balance sheet dates. The following table details the recorded investment at December 31, 2018 and 2017 of loans that have been restructured during the years ended December 31, 2018 and 2017 by type of modification: Extended Maturity Adjusted Payment Schedule Total (in thousands, except number of contracts) Number of Contracts Balance at Period End Number of Contracts Balance at Period End Number of Contracts Balance at Period End Year Ended December 31, 2018 Commercial Business loans — $ — 2 $ 2,411 2 $ 2,411 Energy loans — — 5 10,047 5 10,047 Total — $ — 7 $ 12,458 $ 7 $ 12,458 Year Ended December 31, 2017 Commercial Business loans 1 $ 712 2 $ 6,928 $ 3 $ 7,640 Energy loans 1 — — — 1 — Total 2 $ 712 2 $ 6,928 $ 4 $ 7,640 Restructured loans generally include terms to temporarily place the loan on interest only, extend the payment terms or reduce the interest rate. We did not forgive any principal on the above loans. At December 31, 2018 , all of the above loans restructured in 2018 are on non-accrual. The restructuring of the loans did not have a significant impact on our allowance for loan losses at December 31, 2018 or 2017 . As of December 31, 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	12 Months Ended
	Dec. 31, 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: Year ended December 31, (in thousands) 2018 2017 2016 Beginning balance $ 11,742 $ 18,961 $ 278 Additions — — 18,822 Sales (11,663 ) (1,108 ) (139 ) Valuation allowance for OREO — — — Direct write-downs — (6,111 ) — Ending balance $ 79 $ 11,742 $ 18,961 During 2017, we recorded a $6.1 million write-down on one asset. In 2018, we sold this asset and recorded a $2.0 million gain on sale. The gain on sale was recorded in other non-interest income.

Certain Transfers of Financial

Certain Transfers of Financial Assets	12 Months Ended
	Dec. 31, 2018
Transfers and Servicing [Abstract]
Certain Transfers of Financial Assets	Certain Transfers of Financial Assets The table below presents a reconciliation of the changes in loans held for sale: Year Ended December 31, (in thousands) 2018 2017 Outstanding balance: Beginning balance $ 1,012,580 $ 980,414 Loans purchased 6,753,709 5,556,964 Payments and loans sold (5,816,504 ) (5,524,798 ) Ending balance(1) 1,949,785 1,012,580 Fair value adjustment: Beginning balance (1,576 ) 8,333 Increase/(decrease) to fair value 21,265 9,909 Ending balance 19,689 (1,576 ) Loans held for sale at fair value(1) $ 1,969,474 $ 1,011,004 (1) Includes $299,000 and $3.3 million of loans held for sale that are carried at lower of cost or market as of December 31, 2018 and 2017 , respectively. No loans held for sale were on non-accrual as of December 31, 2018 or December 31, 2017 . At December 31, 2018 and December 31, 2017 , we had $16.8 million and $19.7 million , respectively, in loans held for sale that were 90 days or more past due. The $16.8 million in loans held for sale that were 90 days or more past due at December 31, 2018 included $16.0 million in loans guaranteed by U.S. government agencies that were purchased 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. At December 31, 2017 $19.0 million of the $19.7 million in loans held for sale that were 90 days or more past due were 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 held for sale on our balance sheet regardless of whether the repurchase option has been exercised. From time to time we retain the right to service the loans sold through our MCA program, creating MSRs which are recorded as assets on our balance sheet. A summary of MSR activity is as follows: Year Ended December 31, (in thousands) 2018 2017 MSRs: Balance, beginning of year $ 88,150 $ 28,536 Capitalized servicing rights 39,149 67,970 Amortization (9,278 ) (8,356 ) Sales (75,547 ) — Balance, end of period $ 42,474 $ 88,150 Valuation allowance: Balance, beginning of year $ 2,823 $ — Increase in valuation allowance (2,823 ) 2,823 Balance, end of period $ — $ 2,823 MSRs, net(1) $ 42,474 $ 85,327 MSRs, fair value $ 44,502 $ 86,321 At December 31, 2018 and 2017 , our servicing portfolio of residential mortgage loans had an outstanding principal balance of $3.9 billion and $7.0 billion , respectively. The decline in MSRs, as well as in the outstanding balance of loans in our servicing portfolio, resulted primarily from the completion of MSR sales in 2018, as well as our strategic decision to retain fewer MSRs on loans sold through our MCA program in 2018. In connection with the servicing of these loans, we hold deposits in the name of investors 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 bank accounts at the Bank. These deposits, included in total non-interest-bearing deposits on the consolidated balance sheets, were $37.9 million at December 31, 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 review the key assumptions used in the discounted cash flow model and make adjustments as necessary to estimate the fair value of the MSRs. At December 31, 2017 , the estimated fair value of MSRs was adjusted in anticipation of a sale of Ginnie Mae MSRs in the first quarter of 2018, which resulted in a $2.8 million impairment charge. There was no impairment charge at December 31, 2018 . The following summarizes the assumptions used by management to determine the fair value of MSRs: December 31, 2018 2017 Average discount rates 9.55 % 9.90 % Expected prepayment speeds 9.77 % 9.99 % Weighted-average life, in years 7.0 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: December 31, (in thousands) 2018 2017 50 bp adverse change in prepayment speed $ (6,028 ) $ (11,896 ) 100 bp adverse change in prepayment speed (11,629 ) (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. Our estimated repurchase, indemnification and make whole obligation exposure totaled $1.6 million and $1.3 million at December 31, 2018 and December 31, 2017 , respectively, and is recorded in other liabilities in the consolidated balance sheets. We incurred $ 258,000 in losses due to repurchase, indemnification and make-whole obligations during the year ended December 31, 2018 compared to $31,000 in 2017 .

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill and other intangible assets are summarized as follows: (in thousands) Gross Goodwill and Intangible Assets Accumulated Amortization Net Goodwill and Intangible Assets December 31, 2018 Goodwill $ 15,468 $ (374 ) $ 15,094 Intangible assets—customer relationships and trademarks 9,006 (5,530 ) 3,476 Total goodwill and intangible assets $ 24,474 $ (5,904 ) $ 18,570 December 31, 2017 Goodwill $ 15,468 $ (374 ) $ 15,094 Intangible assets—customer relationships and trademarks 9,006 (5,060 ) 3,946 Total goodwill and intangible assets $ 24,474 $ (5,434 ) $ 19,040 Amortization expense related to intangible assets totaled $470,000 in 2018 , $472,000 in 2017 and $448,000 in 2016 . The estimated aggregate future amortization expense for intangible assets remaining as of December 31, 2018 is as follows: (in thousands) 2019 $ 470 2020 432 2021 405 2022 405 2023 382 Thereafter 1,382 Total $ 3,476

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Premises and Equipment	Premises and Equipment Premises and equipment are summarized as follows: December 31, (in thousands) 2018 2017 Premises $ 27,999 $ 25,790 Furniture and equipment 35,130 32,234 Total cost 63,129 58,024 Accumulated depreciation (39,327 ) (32,848 ) Total premises and equipment, net $ 23,802 $ 25,176 Depreciation expense for the above premises and equipment was approximately $9.0 million, $6.9 million and $6.0 million in 2018 , 2017 and 2016 , respectively. We lease various premises under operating leases with various expiration dates extending through March 2032. Rent expense incurred under operating leases totaled approximately $16.5 million , $14.4 million and $13.7 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. Minimum future lease payments under operating leases are as follows at December 31, 2018 : (in thousands) Minimum Payments 2019 $ 14,652 2020 15,549 2021 15,846 2022 15,012 2023 14,070 2024 and thereafter 28,666 Total $ 103,795

Deposits

Deposits	12 Months Ended
	Dec. 31, 2018
Deposits [Abstract]
Deposits	Deposits Deposits are summarized as follows: December 31, (in thousands) 2018 2017 Non-interest-bearing demand deposits $ 7,317,161 $ 7,812,660 Interest-bearing deposits Transaction 3,051,535 2,567,208 Savings 8,222,893 8,214,059 Time 2,014,524 529,253 Total interest-bearing deposits 13,288,952 11,310,520 Total deposits $ 20,606,113 $ 19,123,180 The scheduled maturities of interest-bearing time deposits were as follows at December 31, 2018 : (in thousands) 2019 $ 1,990,962 2020 21,894 2021 778 2022 263 2023 127 2024 and after 500 Total $ 2,014,524 At December 31, 2018 and 2017 , interest-bearing time deposits of $250,000 or more were approximately $270.2 million and $300.5 million, respectively.

Short-Term and Other Borrowings

Short-Term and Other Borrowings	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Short-Term and Other Borrowings	Borrowings The following table summarizes our short-term and other borrowings: (dollar amounts in thousands) Federal Funds Purchased Customer Repurchase Agreements FHLB Borrowings December 31, 2018 Amount outstanding at year-end $ 629,169 $ 12,005 $ 3,900,000 Interest rate at year-end 2.54 % 0.09 % 2.56 % Average balance outstanding during the year $ 323,140 $ 9,812 $ 1,769,452 Weighted-average interest rate during the year 2.02 % 0.09 % 2.05 % Maximum month-end outstanding during the year $ 629,169 $ 13,835 $ 4,000,000 December 31, 2017 Amount outstanding at year-end $ 359,338 $ 5,702 $ 2,800,000 Interest rate at year-end 1.45 % 0.03 % 1.35 % Average balance outstanding during the year $ 215,895 $ 6,590 $ 1,395,753 Weighted-average interest rate during the year 1.20 % 0.04 % 1.08 % Maximum month-end outstanding during the year $ 544,203 $ 8,727 $ 2,800,000 December 31, 2016 Amount outstanding at year-end $ 101,800 $ 7,775 $ 2,000,000 Interest rate at year-end 0.80 % 0.05 % 0.61 % Average balance outstanding during the year $ 90,904 $ 15,380 $ 1,367,267 Weighted-average interest rate during the year 0.57 % 0.06 % 0.43 % Maximum month-end outstanding during the year $ 263,989 $ 18,884 $ 2,025,000 The following table summarizes our other borrowing capacities net of balances outstanding. As of December 31, 2018 , all are scheduled to mature within one year. December 31, (in thousands) 2018 2017 2016 FHLB borrowing capacity relating to loans $ 4,568,842 $ 3,890,995 $ 3,057,915 FHLB borrowing capacity relating to securities 721 2,071 1,653 Total FHLB borrowing capacity(1) $ 4,569,563 $ 3,893,066 $ 3,059,568 Unused Federal funds lines available from commercial banks $ 620,000 $ 885,000 $ 1,118,000 Unused Federal Reserve Borrowings capacity $ 4,933,965 $ 4,114,594 $ 3,179,087 Unused revolving line of credit(2) $ 130,000 $ 130,000 $ 130,000 (1) FHLB borrowings are collateralized by a blanket floating lien on certain real estate secured loans, mortgage finance assets and also certain pledged securities. (2) Unsecured revolving, non-amortizing line of credit with maturity date of December 17, 2019. Proceeds may be used for general corporate purposes, including funding regulatory capital infusions into the Bank. The loan agreement contains customary financial covenants and restrictions. No borrowings were made against this line of credit during 2018 or 2017; the average borrowings during the year ended December 31, 2016 were $6.8 million .

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2018
Subordinated Borrowings [Abstract]
Long-Term Debt	Long-Term Debt From November 2002 to September 2006 various Texas Capital Statutory Trusts were created and subsequently issued floating rate trust preferred securities in various private offerings totaling $113.4 million . As of December 31, 2018 , the details of the trust preferred subordinated debentures are summarized below: (dollar amounts in thousands) Texas Capital Texas Capital Texas Capital Texas Capital Texas Capital Date issued November 19, 2002 April 10, 2003 October 6, 2005 April 28, 2006 September 29, 2006 Trust preferred securities issued $10,310 $10,310 $25,774 $25,774 $41,238 Floating or fixed rate securities Floating Floating Floating Floating Floating Interest rate on subordinated debentures 3 month LIBOR 3 month LIBOR 3 month LIBOR 3 month LIBOR 3 month LIBOR Maturity date November 2032 April 2033 December 2035 June 2036 December 2036 On September 21, 2012, the Company issued $111.0 million of subordinated notes. The notes mature in September 2042 and bear interest at a rate of 6.50% per annum, payable quarterly. The indenture governing the notes contains customary covenants and restrictions. On January 31, 2014, the Bank issued $175.0 million of subordinated notes in an offering to institutional investors exempt from registration under Section 3(a)(2) of the Securities Act of 1933 and 12 C.F.R. Part 16. The notes mature in January 2026 and bear interest at a rate of 5.25% per annum, payable semi-annually. The notes are unsecured and are subordinate to the Bank’s obligations to its depositors, its obligations under banker’s acceptances and letters of credit, certain obligations to Federal Reserve Banks and the FDIC and the Bank’s obligations to its other creditors, except any obligations which expressly rank on a parity with or junior to the notes. The notes qualify as Tier 2 capital for regulatory capital purposes, subject to applicable limitations.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes 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 remeasured certain deferred tax assets and liabilities based on the rates at which they were expected to be recognized in the future, which was generally 21%, and as a result we recorded a $17.6 million provisional remeasurement write-off, which was recorded as additional income tax expense during 2017. During 2018, after completing the full analysis of the impact of the Tax Act, we recorded an insignificant additional provision. Income tax expense/(benefit) consists of the following: Year ended December 31, (in thousands) 2018 2017 2016 Current: Federal $ 82,556 $ 94,112 $ 86,612 State 3,808 3,257 2,412 Total 86,364 97,369 89,024 Deferred: Federal (6,400 ) 31,276 (2,946 ) State — — — Total (6,400 ) 31,276 (2,946 ) Total expense: Federal 76,156 125,388 83,666 State 3,808 3,257 2,412 Total $ 79,964 $ 128,645 $ 86,078 The reconciliation of our effective income tax rate to the U.S. federal statutory tax rate is as follows: Year ended December 31, 2018 2017 2016 U.S. statutory rate 21 % 35 % 35 % State taxes 1 % 1 % 1 % Non-deductible expenses 1 % 1 % 1 % Deferred tax asset remeasurement write-off — % 5 % — % Non-taxable income (1 )% (1 )% (1 )% Other (1 )% (1 )% — % Effective tax rate 21 % 40 % 36 % The tax effect of unrealized gains and losses on available-for-sale debt securities is recorded to other comprehensive income and is not a component of income tax expense/(benefit). We are no longer subject to U.S. federal income tax examinations for years before 2015 or state and local income tax examinations for years before 2014 . The table below summarizes significant components of our deferred tax assets and liabilities utilizing the federal corporate income tax rate of 21%. Management believes it is more likely than not that all of the deferred tax assets will be realized. Our net deferred tax assets are included in other assets in the consolidated balance sheets. December 31, (in thousands) 2018 2017 Deferred tax assets: Allowance for credit losses $ 44,224 $ 42,213 Loan origination fees 11,328 10,084 Stock compensation 3,363 4,460 Non-accrual interest 1,724 1,680 Non-qualified deferred compensation 2,211 1,217 Other 2,517 3,380 Total deferred tax assets 65,367 63,034 Deferred tax liabilities: Loan origination costs (2,049 ) (1,304 ) Leases (9,000 ) (6,850 ) MSRs (9,184 ) (17,619 ) Depreciation (8,233 ) (7,354 ) Unrealized gain on securities (138 ) (138 ) Other (2,662 ) (2,068 ) Total deferred tax liabilities (31,266 ) (35,333 ) Net deferred tax asset $ 34,101 $ 27,701

Stock-Based Compensation and Em

Stock-Based Compensation and Employee Benefits	12 Months Ended
	Dec. 31, 2018
Compensation Related Costs [Abstract]
Stock-Based Compensation and Employee Benefits	Stock-Based Compensation and Employee Benefits We have a qualified retirement plan, with a salary deferral feature designed to qualify under Section 401 of the Internal Revenue Code (“the 401(k) Plan”). The 401(k) Plan permits our employees to defer a portion of their compensation. Matching contributions may be made in amounts and at times determined by the Company. We contributed approximately $9.6 million , $8.4 million , and $6.8 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. Employees are eligible to participate in the 401(k) Plan when they meet certain requirements concerning minimum age and period of credited service. All contributions to the 401(k) Plan are invested in accordance with participant elections among certain investment options. During 2000, we implemented an Employee Stock Purchase Plan (“ESPP”). Employees are eligible for the plan when they meet certain requirements concerning period of credited service and minimum hours worked. Eligible employees may contribute a minimum of 1% to a maximum of 10% of eligible compensation up to the Section 423 of the Internal Revenue Code limit of $25,000. In 2006, stockholders approved the 2006 ESPP, which allocated 400,000 shares for purchase. As of December 31, 2018 , 2017 and 2016 , 143,348 , 132,285 and 124,572 shares had been purchased on behalf of the employees under the 2006 ESPP. We have stock-based compensation plans under which equity-based compensation grants are made by the board of directors, or its designated committee. Grants are subject to vesting requirements. Under the plans, we may grant, among other things, non-qualified stock options, incentive stock options, restricted stock, restricted stock units (“RSUs”), stock appreciation rights (“SARs”), cash-settled performance units or any combination thereof to employees and non-employee directors. A total of 2,550,000 shares are authorized for grant under the plans. Total shares remaining available for grant under the plans at December 31, 2018 were 2,121,515 . We also offer a non-qualified deferred compensation plan for our executives and key members of management in order to assist us in attracting and retaining these individuals. Participants in the plan may elect to defer up to 75% of their annual salary and/or short-term incentive payout into deferral accounts that mirror the gains or losses of investments selected by the participants. The plan allows us to make discretionary contributions on behalf of a participant as well as matching contributions. We made matching contributions of $1.0 million in 2018 and discretionary contributions of $260,000 in 2017 . All participant contributions to the plan and any related earnings are immediately vested and may be withdrawn upon the participant's separation from service, death or disability or upon a date specified by the participant. The deferrals are recorded to salaries and benefits as a reduction and a corresponding accrual is recorded in other liabilities. A summary of our SAR activity and related information is as follows. These rights are time based and generally vest ratably over a period of five years. December 31, 2018 December 31, 2017 December 31, 2016 SARs Weighted Average Exercise Price SARs Weighted Average Exercise Price SARs Weighted Average Exercise Price SARs outstanding at beginning of year 74,363 $ 30.12 125,863 $ 31.68 360,544 $ 25.73 SARs granted — — — — — — SARs exercised (33,013 ) 31.35 (51,500 ) 33.94 (234,681 ) 22.54 SARs forfeited — — — — — — SARs outstanding at year-end 41,350 $ 29.13 74,363 $ 30.12 125,863 $ 31.68 SARs vested and exercisable at year-end 39,750 $ 27.81 60,463 $ 26.02 94,463 $ 26.73 Weighted average remaining contractual life of SARs vested (in years) 2.33 2.82 3.62 Compensation expense $ 121,000 $ 265,000 $ 307,000 Unrecognized compensation expense $ 6,000 $ 127,000 $ 392,000 Weighted average period over which unrecognized compensation expense is expected to be recognized (in years) 0.17 0.75 1.52 Fair value of shares vested during the year $ 210,807 $ 294,000 $ 337,000 Weighted average remaining contractual life of SARs (in years) 2.44 3.35 4.32 Intrinsic value of SARs exercised $ 925,479 $ 3,802,000 $ 4,881,000 A summary of our RSU activity and related information is as follows. Grants of RSUs include both performance-based and time-based vesting conditions and generally vest over a three-year period. December 31, 2018 December 31, 2017 December 31, 2016 RSUs Weighted Average Grant Date Fair Value RSUs Weighted RSUs Weighted RSUs outstanding at beginning of year 423,732 $ 60.01 425,055 $ 51.28 333,174 $ 48.60 RSUs granted 95,891 88.07 121,243 80.40 213,577 51.75 RSUs vested (121,507 ) 54.97 (102,057 ) 48.93 (94,296 ) 42.87 RSUs forfeited (48,583 ) 63.60 (20,509 ) 54.75 (27,400 ) 51.18 RSUs outstanding at year-end 349,533 $ 69.11 423,732 $ 60.01 425,055 $ 51.28 Compensation expense $ 8,803,000 $ 7,790,000 $ 4,771,000 Unrecognized compensation expense $ 16,538,000 $ 18,730,000 $ 17,167,000 Weighted average period over which unrecognized compensation expense is expected to be recognized (in years) 2.90 3.15 3.37 Weighted average remaining contractual life of RSUs (in years) 8.13 8.33 8.65 In 2016, we began granting shares of restricted stock ("RSAs") to non-employee directors at the time that they join the board. These restricted shares generally vest ratably over a period of three years. We recorded compensation expense of $62,000, $61,000 and $35,000 for the years ended December 31, 2018, 2017 and 2016, respectively. Total compensation cost for all share-based arrangements was $9.0 million, $8.1 million and $5.1 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. We granted 138,773 cash-settled units in 2018 , with a total of 325,719 outstanding at December 31, 2018 , all of which are time-based and vest ratably over a period of four years . We granted 121,260 and 224,071 cash-settled units in 2017 and 2016 , respectively. Since these units have a cash payout feature, they are accounted for under the liability method with related expense based on the stock price at period end. Compensation cost for the cash-settled units was $8.0 million, $13.9 million and $8.5 million for the years ended December 31, 2018 , 2017 and 2016 , respectively.

Financial Instruments with Off-

Financial Instruments with Off-Balance Sheet Risk	12 Months Ended
	Dec. 31, 2018
Risks and Uncertainties [Abstract]
Financial Instruments with Off-Balance Sheet Risk	Financial Instruments with Off-Balance Sheet Risk The table below presents our financial instruments with off-balance sheet risk, as well as the activity in the allowance for off-balance sheet credit losses related to those financial instruments. This allowance is recorded in other liabilities on the consolidated balance sheet. Year Ended December 31, (in thousands) 2018 2017 Beginning balance of allowance for off-balance sheet credit losses $ 9,071 $ 11,422 Provision for off-balance sheet credit losses 2,363 (2,351 ) Ending balance of allowance for off-balance sheet credit losses $ 11,434 $ 9,071 Commitments to extend credit - period end balance $ 8,030,198 $ 6,957,847 Standby letters of credit - period end balance $ 236,537 $ 230,958

Regulatory Restrictions

Regulatory Restrictions	12 Months Ended
	Dec. 31, 2018
Regulatory Capital Requirements [Abstract]
Regulatory Restrictions	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 was 1.875% and during 2017 was 1.25%. 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 regulation 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 December 31, 2018 , that the Company and the Bank meet 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 December 31, 2018 and 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 change could reduce 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 effect on 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 (dollars in thousands) Capital Amount Ratio Capital Amount Ratio Capital Amount Ratio Capital Amount Ratio December 31, 2018 CET1 Company $ 2,330,599 8.58 % $ 1,732,501 6.38 % $ 1,902,354 7.00 % N/A N/A Bank 2,340,988 8.62 % 1,731,955 6.38 % 1,901,755 7.00 % 1,765,915 6.50 % Total capital (to risk-weighted assets) Company 3,074,097 11.31 % 2,683,679 9.88 % 2,853,532 10.50 % N/A N/A Bank 2,925,872 10.77 % 2,682,833 9.88 % 2,852,632 10.50 % 2,716,793 10.00 % Tier 1 capital (to risk-weighted assets) Company 2,589,374 9.53 % 2,140,149 7.88 % 2,310,002 8.50 % N/A N/A Bank 2,499,763 9.20 % 2,139,474 7.88 % 2,309,274 8.50 % 2,173,434 8.00 % Tier 1 capital (to average assets)(1) Company 2,589,374 9.87 % 1,049,694 4.00 % 1,049,694 4.00 % N/A N/A Bank 2,499,763 9.53 % 1,049,296 4.00 % 1,049,296 4.00 % 1,311,620 5.00 % 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, 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 December 31, 2018 , our total mortgage finance loans were $5.9 billion compared to the average for the quarter ended December 31, 2018 of $5.0 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 period-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 period-end balance is representative of risk characteristics that would justify higher allocations. However, we monitor our capital allocation to confirm that all capital levels remain above well-capitalized levels. Dividends that may be paid by banks are routinely restricted by various regulatory authorities. The amount that can be paid in any calendar year without prior approval of our 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 2018 , 2017 or 2016 . The required reserve balances at the Federal Reserve at December 31, 2018 and 2017 were approximately $157.7 million and $197.3 million, respectively.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The following table presents the computation of basic and diluted earnings per share: Year ended December 31, (in thousands except per share data) 2018 2017 2016 Numerator: Net income $ 300,824 $ 197,063 $ 155,119 Preferred stock dividends 9,750 9,750 9,750 Net income available to common stockholders $ 291,074 $ 187,313 $ 145,369 Denominator: Denominator for basic earnings per share—weighted average shares 49,936,702 49,587,169 46,239,210 Effect of employee stock-based awards(1) 218,275 239,008 128,228 Effect of warrants to purchase common stock 117,895 433,657 398,464 Denominator for dilutive earnings per share—adjusted weighted average shares and assumed conversions 50,272,872 50,259,834 46,765,902 Basic earnings per common share $ 5.83 $ 3.78 $ 3.14 Diluted earnings per common share $ 5.79 $ 3.73 $ 3.11 (1) SARs and RSUs outstanding of 27,100 , 13,500 and 150,416 in 2018 , 2017 and 2016 , respectively, have not been included in diluted earnings per share because to do so would have been antidilutive for the periods presented.

Fair Value Disclosures

Fair Value Disclosures	12 Months Ended
	Dec. 31, 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. 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. 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 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. Assets and liabilities measured at fair value are as follows: Fair Value Measurements Using (in thousands) Level 1 Level 2 Level 3 December 31, 2018 Available-for-sale debt securities:(1) Residential mortgage-backed securities $ — $ 7,242 $ — Tax-exempt asset-backed securities — — 95,804 Equity securities(1)(2) 10,262 6,908 — Loans held for sale(3) — 1,952,760 16,415 Loans held for investment(4)(6) — — 29,885 OREO(5)(6) — — 79 Derivative assets(7) — 21,806 — Derivative liabilities(7) — 41,375 — Non-qualified deferred compensation plan liabilities(8) 10,148 — — 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 purchased through our MCA program 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 generally correspond to the fair value of the invested assets, and are measured at fair value on a recurring basis, generally monthly. Level 3 Valuations The following table presents a reconciliation of the level 3 fair value category measured at fair value on a recurring basis using Level 3 inputs: Net Realized/Unrealized Gains (Losses) (in thousands) Balance at Beginning of Period Purchases / Additions Sales / Reductions Realized Unrealized Balance at End of Period Year ended December 31, 2018 Tax-exempt asset-backed securities(1) $ — $ 95,521 $ (3 ) $ — $ 286 $ 95,804 Loans held for sale(2) $ — $ 38,430 $ (20,591 ) $ (173 ) $ (1,251 ) $ 16,415 (1) Unrealized gains/(losses) on available-for-sale debt securities are recorded in AOCI. Realized gains/(losses) are recorded in other non-interest income. (2) Realized and unrealized gains/(losses) on loans held for sale are recorded in gain/(loss) on sale of loans held for sale. Tax-exempt asset-backed securities The fair value of tax-exempt asset-backed securities is based on a discounted cash flow model, which utilizes Level 3, or unobservable, inputs, the most significant of which were a discount rate and weighted-average life. At December 31, 2018 , a discount rate of 4.21% and a weighted-average life of 9.2 years were utilized to determine the fair value of these securities. 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 December 31, 2018 , the fair value of these loans was calculated using a weighted-average discounted price of 92.9% . Loans held for investment Certain impaired loans held for investment are reported at fair value through a specific valuation allowance allocation of the allowance for loan losses based upon the fair value of the underlying collateral. The $29.9 million fair value of loans held for investment at December 31, 2018 reported above includes impaired loans held for investment with a carrying value of $32.2 million that were reduced by specific valuation allowance allocations totaling $2.3 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 December 31, 2018 and 2017 , OREO had a carrying value of $79,000 and $11.7 million , respectively, with no specific valuation allowance. The fair value of OREO was computed based on third party appraisals, which are Level 3 valuation 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: December 31, 2018 December 31, 2017 (in thousands) Carrying Amount Estimated Fair Value Carrying Estimated Financial assets: Level 1 inputs: Cash and cash equivalents $ 3,080,065 $ 3,080,065 $ 2,905,591 $ 2,905,591 Investment securities 10,262 10,262 5,460 5,460 Level 2 inputs: Investment securities 14,150 14,150 18,051 18,051 Loans held for sale 1,953,059 1,953,059 1,011,004 1,011,004 Derivative assets 21,806 21,806 16,719 16,719 Level 3 inputs: Investment securities 95,804 95,804 — — Loans held for sale 16,415 16,415 — — Loans held for investment, net 22,376,552 22,347,876 20,489,757 20,480,802 Financial liabilities: Level 2 inputs: Federal funds purchased 629,169 629,169 359,338 359,338 Customer repurchase agreements 12,005 12,005 5,702 5,702 Other borrowings 3,900,000 3,900,000 2,800,000 2,800,000 Subordinated notes 281,767 283,349 281,406 285,485 Trust preferred subordinated debentures 113,406 113,406 113,406 113,406 Derivative liabilities 41,375 41,375 17,377 17,377 Level 3 inputs: Deposits 20,606,113 20,608,494 19,123,180 19,124,121 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 discounted cash flow 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. 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.

Parent Company Only

Parent Company Only	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
Parent Company Only	Parent Company Only Summarized financial information for Texas Capital Bancshares, Inc. – Parent Company Only are as follows: Balance Sheet December 31, (in thousands) 2018 2017 Assets Cash and cash equivalents $ 89,561 $ 144,635 Loans held for investment (net of unearned income) 7,500 7,500 Investment in subsidiaries 2,534,341 2,184,601 Other assets 87,451 86,300 Total assets $ 2,718,853 $ 2,423,036 Liabilities and Stockholders’ Equity Other liabilities $ 1,471 $ 1,244 Subordinated notes 108,614 108,513 Trust preferred subordinated debentures 113,406 113,406 Total liabilities 223,491 223,163 Preferred stock 150,000 150,000 Common stock 502 496 Additional paid-in capital 978,042 971,457 Retained earnings 1,366,308 1,077,500 Treasury stock (8 ) (8 ) Accumulated other comprehensive income 518 428 Total stockholders’ equity 2,495,362 2,199,873 Total liabilities and stockholders’ equity $ 2,718,853 $ 2,423,036 Statement of Earnings Year ended December 31, (in thousands) 2018 2017 2016 Interest on loans $ 3,398 $ 3,271 $ 3,250 Dividend income 10,400 10,400 10,400 Other income 142 108 90 Total income 13,940 13,779 13,740 Other non-interest income 7 13 152 Interest expense 12,031 10,908 10,525 Salaries and employee benefits 588 489 431 Legal and professional 2,020 1,700 1,429 Other non-interest expense 2,013 1,761 1,594 Total expense 16,652 14,858 13,979 Income (loss) before income taxes and equity in undistributed income of subsidiary (2,705 ) (1,066 ) (87 ) Income tax expense (benefit) (587 ) (371 ) (33 ) Income (loss) before equity in undistributed income of subsidiary (2,118 ) (695 ) (54 ) Equity in undistributed income of subsidiary 300,758 194,118 151,445 Net income 298,640 193,423 151,391 Preferred stock dividends 9,750 9,750 9,750 Net income available to common stockholders $ 288,890 $ 183,673 $ 141,641 Statements of Cash Flows Year ended December 31, (in thousands) 2018 2017 2016 Operating Activities Net income $ 298,640 $ 193,423 $ 151,391 Adjustments to reconcile net income to net cash used in operating activities: Equity in undistributed income of subsidiary (300,758 ) (194,118 ) (151,445 ) Amortization 101 101 101 Increase in other assets (1,152 ) (739 ) (10 ) Excess tax benefits from stock-based compensation arrangements — — (2,013 ) Increase (decrease) in other liabilities 227 (40 ) 165 Net cash used in operating activities (2,942 ) (1,373 ) (1,811 ) Investing Activities Net increase in loans held for investment — (7,500 ) — Investments in and advances to subsidiaries (40,000 ) (55,000 ) (57,000 ) Net cash used in investing activities (40,000 ) (62,500 ) (57,000 ) Financing Activities Proceeds from sale of stock related to stock-based awards (2,382 ) (2,241 ) (2,481 ) Proceeds from sale of common stock — — 236,467 Preferred dividends paid (9,750 ) (9,750 ) (9,750 ) Excess tax benefits from stock-based compensation arrangements — — 2,013 Net cash provided by (used in) financing activities (12,132 ) (11,991 ) 226,249 Net increase (decrease) in cash and cash equivalents (55,074 ) (75,864 ) 167,438 Cash and cash equivalents at beginning of year 144,635 220,499 53,061 Cash and cash equivalents at end of year $ 89,561 $ 144,635 $ 220,499

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions During 2018 and 2017, we have had transactions with our directors, executive officers and their affiliates and our employees. These transactions were made in the ordinary course of business and include extensions of credit and deposit transactions. The Bank had approximately $13.5 million in deposits from related parties, including directors, stockholders and their affiliates at both December 31, 2018 and 2017 . In February 2018, the Bank signed an agreement with Total System Services, Inc. ("TSYS"), under which TSYS will provide transaction processing services to the Bank in exchange for a fee, estimated to be $400,000 to $600,000 per year. A member of the Company’s board of directors, is the Senior Executive Vice President and Chief Information Officer of TSYS.

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments The notional amounts and estimated fair values of derivative positions outstanding are presented in the following table: December 31, 2018 December 31, 2017 Estimated Fair Value Estimated Fair Value (in thousands) Notional Amount Asset Derivative Liability Derivative Notional Amount Asset Derivative Liability Derivative Non-hedging derivatives: Financial institution counterparties: Commercial loan/lease interest rate swaps $ 1,579,328 $ 7,978 $ 16,719 $ 1,393,764 $ 4,736 $ 15,482 Commercial loan/lease interest rate caps 606,950 1,109 4 242,700 421 7 Foreign currency forward contracts 39,737 2,263 59 2,466 4 69 Customer counterparties: Commercial loan/lease interest rate swaps 1,579,328 16,719 7,978 1,393,764 15,482 4,736 Commercial loan/lease interest rate caps 606,950 4 1,109 242,700 7 421 Foreign currency forward contracts 39,737 59 2,263 2,466 69 4 Economic hedging interest rate derivatives: Loan purchase commitments 167,984 1,442 6 253,815 635 190 Forward sale commitments 1,928,527 — 21,005 1,086,224 — 1,103 Gross derivatives 29,574 49,143 21,354 22,012 Offsetting derivative assets/liabilities (7,768 ) (7,768 ) (4,635 ) (4,635 ) Net derivatives included in the consolidated balance sheets $ 21,806 $ 41,375 $ 16,719 $ 17,377 The weighted-average receive and pay interest rates for interest rate swaps outstanding were as follows: December 31, 2018 Weighted-Average Interest Rate December 31, 2017 Weighted-Average Interest Rate Received Paid Received Paid Non-hedging interest rate swaps 4.24 % 4.20 % 3.59 % 4.34 % The weighted-average strike rate for outstanding interest rate caps was 3.20% at December 31, 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 $18.7 million at December 31, 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 sale commitments. At December 31, 2018 , we had $25.3 million in cash collateral pledged for these derivatives, of which $11.2 million was included in interest-bearing deposits in other banks and $14.1 million was included in accrued interest receivable and other assets. At December 31, 2017 , we had $15.2 million in cash collateral pledged for these derivatives, of which $14.0 million was included in interest-bearing deposits 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 13 risk participation agreements where we are a participant bank with a notional amount of $149.1 million at December 31, 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 $1.5 million at December 31, 2018 and $221,000 at December 31, 2017 . The fair value of these exposures was insignificant to the consolidated financial statements at both December 31, 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 9 risk participation agreements where we are the lead bank having a notional amount of $114.8 million at December 31, 2018 , compared to 10 agreements having a notional amount of $86.3 million at December 31, 2017 .

Stockholder's Equity

Stockholder's Equity	12 Months Ended
	Dec. 31, 2018
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Stockholders’ Equity On December 2, 2016, we completed a sale of 3.45 million shares of our common stock in a public offering. Net proceeds from the sale totaled $236.4 million . The additional equity was used for general corporate purposes, including repayment of $20.0 million of short-term debt and as additional capital to support continued loan growth.

Quarterly Financial Data

Quarterly Financial Data	12 Months Ended
	Dec. 31, 2018
Selected Quarterly Financial Information [Abstract]
Quarterly Financial Information	Quarterly Financial Data (unaudited) The tables below summarize our quarterly financial information: 2018 Selected Quarterly Financial Data (in thousands, except per share data) Fourth Third Second First Interest income $ 321,718 $ 301,754 $ 286,852 $ 253,869 Interest expense 81,045 69,579 55,140 43,569 Net interest income 240,673 232,175 231,712 210,300 Provision for credit losses 35,000 13,000 27,000 12,000 Net interest income after provision for credit losses 205,673 219,175 204,712 198,300 Non-interest income 15,280 25,518 17,279 19,947 Non-interest expense 129,862 136,143 132,131 126,960 Income before income taxes 91,091 108,550 89,860 91,287 Income tax expense 19,200 22,998 18,424 19,342 Net income 71,891 85,552 71,436 71,945 Preferred stock dividends 2,437 2,438 2,437 2,438 Net income available to common stockholders $ 69,454 $ 83,114 $ 68,999 $ 69,507 Basic earnings per share: $ 1.38 $ 1.66 $ 1.39 $ 1.40 Diluted earnings per share: $ 1.38 $ 1.65 $ 1.38 $ 1.38 2017 Selected Quarterly Financial Data (in thousands, except per share data) Fourth Third Second First Interest income $ 249,519 $ 237,643 $ 208,191 $ 183,946 Interest expense 38,870 33,282 25,232 20,587 Net interest income 210,649 204,361 182,959 163,359 Provision for credit losses 2,000 20,000 13,000 9,000 Net interest income after provision for credit losses 208,649 184,361 169,959 154,359 Non-interest income 19,374 19,003 18,769 17,110 Non-interest expense 133,138 114,830 111,814 106,094 Income before income taxes 94,885 88,534 76,914 65,375 Income tax expense 50,143 29,850 25,819 22,833 Net income 44,742 58,684 51,095 42,542 Preferred stock dividends 2,437 2,438 2,437 2,438 Net income available to common stockholders $ 42,305 $ 56,246 $ 48,658 $ 40,104 Basic earnings per share: $ 0.85 $ 1.13 $ 0.98 $ 0.81 Diluted earnings per share: $ 0.84 $ 1.12 $ 0.97 $ 0.80

New Accounting Standards

New Accounting Standards	12 Months Ended
	Dec. 31, 2018
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
New Accounting Standards	New Accounting Standards 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 was 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 have elected 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 lease portfolio as of December 31, 2018, we anticipate recognizing a lease liability on our balance sheet of approximately $75 million with an offsetting right-of-use asset net of lease incentives, with an immaterial impact on our income statement compared to the current lease accounting model.

Operations and Summary of Sig_2

Operations and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 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 or national clientele of commercial borrowers. We are primarily a secured lender, with the majority of our loans held for investment, excluding mortgage finance loans and other national lines of business, being made to businesses headquartered or with operations in Texas.
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.
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 financial instruments and the status of contingencies are particularly susceptible to significant change.
Basic and Diluted Earnings Per Common Share	Basic and Diluted Earnings Per Common Share Basic earnings per common share is based on net income available to common stockholders divided by the weighted-average number of common shares outstanding during the period excluding non-vested stock. Diluted earnings per common share include the dilutive effect of stock options and non-vested stock awards granted using the treasury stock method. A reconciliation of the weighted-average shares used in calculating basic earnings per common share and the weighted average common shares used in calculating diluted earnings per common share for the reported periods is provided in Note 2 — Earnings Per Share.
Accumulated Other Comprehensive Income	Accumulated Other Comprehensive Income Unrealized gains or losses on our available-for-sale debt securities (after applicable income tax expense or benefit) are included in accumulated other comprehensive income (loss), net ("AOCI"). AOCI is reported in the accompanying consolidated statements of stockholders’ equity and consolidated statements of income and other comprehensive income. GAAP does not permit the adjustment of tax amounts in AOCI for changes in tax rates, the effects become stranded in AOCI. 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 "Tax Act") are reclassified from AOCI to retained earnings in accordance with our early adoption of ASU 2018-02 Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income."
Cash and Cash Equivalents	Cash and Cash Equivalents Cash equivalents include amounts due from banks, interest-bearing deposits in other banks, Federal funds sold and securities purchased under resale agreements.
Investment Securities	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 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. The cost of securities sold is based on the specific identification method. All debt securities are available-for-sale as of December 31, 2018 and 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 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.
Loans	Loans Loans Held for Sale Through our mortgage correspondent aggregation ("MCA") program, 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 third parties such as Ginnie Mae or to GSEs such as Fannie Mae or Freddie Mac. In some cases, we retain the mortgage servicing rights. Once purchased, these loans are classified as held for sale and are carried at fair value pursuant to our election of the fair value option in accordance with Accounting Standards Codification ("ASC") 825, Financial Instruments . At the commitment date, we enter into a corresponding forward sale commitment with a third party, typically Ginnie Mae or a GSE, to deliver the loans within a specified timeframe. The estimated gain/loss for the entire transaction (from initial purchase commitment to final delivery of loans) is recorded as an asset or liability. The fair value of loans held for sale is derived from observable current market prices, when available, and includes the fair value of the mortgage servicing rights. Adjustments to reflect unrealized gains and losses resulting from changes in fair value and realized gains and losses upon ultimate sale of the loans are classified as gain/(loss) on sale of loans held for sale in the consolidated statements of income and other comprehensive income. 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 managed through forward sales contracts, which set the price for loans that will be delivered in the next 60 to 90 days. Pursuant to Ginnie Mae servicing guidelines, we have the unilateral right, but not the obligation, to repurchase certain delinquent loans securitized in Ginnie Mae pools, if they meet defined delinquent loan criteria. Once the delinquency criteria have been met, and regardless of whether the repurchase option has been exercised, we account for these loans as if they had been repurchased and recognize the loans and a corresponding liability as held for sale and other liabilities, respectively, in the consolidated balance sheets. If the loans are actually repurchased, the liability is cash settled and the loans continue to be reported as held for sale. As an approved lender, we may collect losses incurred on repurchased loans through a claims process with the government agency. From time to time we hold for sale the guaranteed portion of Small Business Administration 7(a) loans, which are carried at lower of cost or market. Loans Held for Investment Loans held for investment (including financing leases) are stated at the amount of unpaid principal reduced by deferred income (net of costs). Interest on loans is recognized using the simple-interest method on the daily balances of the principal amounts outstanding. Loan origination fees, net of direct loan origination costs, and commitment fees, are deferred and amortized as an adjustment to yield over the life of the loan, or over the commitment period, as applicable. 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 loan agreement. Reserves on impaired loans are measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate or the fair value of the underlying collateral, less cost to sell. Impaired loans, or portions thereof, are charged off when a confirmed loss exists. 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 contractual interest rate, extension of the maturity date at a contractual interest rate lower than the current rate for new debt with similar risk, or a reduction of the face amount of debt, or forgiveness of either principal or accrued interest. A loan continues to qualify as restructured until a consistent payment history or change in borrower’s financial condition has been evidenced, generally 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 modified terms in calendar years after the year of the restructure. The accrual of interest on loans is discontinued when there is a clear indication that the borrower’s cash flow may not be sufficient to meet payments as they become due, which is generally when a loan is 90 days past due. When a loan is placed on non-accrual status, all previously accrued and unpaid interest is reversed. Interest income is subsequently recognized on a cash basis as long as the remaining book balance of the asset is deemed to be collectible. If collectability is questionable, then cash payments are applied to principal. 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. Loans held for investment includes legal ownership interests in mortgage loans that we purchase through our mortgage warehouse lending division. The ownership interests are purchased from unaffiliated mortgage originators who are seeking additional funding through sale of the undivided ownership interests to facilitate their ability to originate loans. The mortgage originator has no obligation to offer and we have no obligation to purchase these interests. The originator closes mortgage loans consistent with underwriting standards established by approved investors, and, at the time of the sale to the investor, our ownership interest and that of the originator are delivered by us to the investor selected by the originator and approved by us. We typically purchase up to a 99% ownership interest in each mortgage with the originator owning the remaining percentage. These mortgage ownership interests are generally held by us for a period of less than 30 days and more typically 10-20 days. Because of conditions in agreements with originators designed to reduce transaction risks, under ASC 860, Transfers and Servicing of Financial Assets (“ASC 860”), the ownership interests do not qualify as participating interests. Under ASC 860, the ownership interests are deemed to be loans to the originators and payments we receive from investors are deemed to be payments made by or on behalf of the originator to repay the loan deemed made to the originator. Because we have an actual, legal ownership interest in the underlying residential mortgage loan, these interests are extensions of credit to the originators that are secured by the mortgage loans as collateral. Due to market conditions or events of default by the investor or the originator, we could be required to purchase the remaining interests in the mortgage loans and hold them beyond the expected 10-20 days. Mortgage loans acquired under these conditions would require mark-to-market adjustments to income and could require future allocations of the allowance for loan losses or be subject to charge off in the event the loans become impaired. Mortgage loan interests purchased and disposed of as expected receive no allocation of the allowance for loan losses due to the minimal loss experience with these assets.
Allowance for Loan Losses	Allowance for Loan Losses The allowance for loan losses is comprised of general reserves, specific reserves for impaired loans and an additional qualitative reserve, all based on our estimate of losses inherent in the portfolio at the balance sheet date, but not yet identified with specified loans. In order to determine the allowance for loan losses, all loans are assigned a credit grade. Loan commitments graded substandard or worse and greater than $500,000 are specifically reviewed for loss potential. Loans deemed to be impaired, as well as restructured loans and loans formerly reported as restructured, are assigned a specific reserve based on the losses expected to be realized from those loans. For purposes of determining the general reserve, the remainder of the portfolio is segregated by product types to recognize differing risk profiles among portfolio segments, and then further segregated by credit grades. Each credit grade is assigned a risk factor, or reserve allocation percentage. These risk factors are multiplied by the outstanding principal balance of each loan and risk-weighted by product type to calculate a required reserve. A similar process is employed to calculate a reserve assigned to off-balance sheet commitments, specifically unfunded loan commitments and letters of credit, and any needed reserve is recorded in other liabilities. Even though portions of the allowance may be allocated to specific loans, the entire allowance is available for any credit that, in management’s judgment, should be charged off. We have several pass credit grades that are assigned to loans based on varying levels of risk, ranging from credits that are secured by cash or marketable securities, to watch credits which have all the characteristics of an acceptable credit risk but warrant more than the normal level of monitoring. Within our criticized/classified credit grades are special mention, substandard, and doubtful. Special mention loans are those that are currently protected by the sound worth and paying capacity of the borrower, but that are potentially weak and constitute an additional credit risk. These loans have the potential to deteriorate to a substandard grade due to the existence of financial or administrative deficiencies. Substandard loans have a well-defined weakness or weaknesses that jeopardize the liquidation of the debt. They are characterized by the distinct possibility that we will sustain some loss if the deficiencies are not corrected. Some substandard loans are inappropriately protected by sound worth and paying capacity of the borrower and of the collateral pledged and may be considered impaired. Substandard loans can be accruing or can be on non-accrual depending on the circumstances of the individual loans. Loans classified as doubtful have all the weaknesses inherent in substandard loans with the added characteristics that the weaknesses make collection or liquidation in full highly questionable and improbable. The possibility of loss is extremely high. All doubtful loans are on non-accrual. The allowance allocation percentages assigned to each credit grade have been developed based primarily on an analysis of our historical loss rates. The level of the allowance reflects management’s continuing evaluation of conditions likely to impact the amount of losses expected to be incurred in the Bank’s loan portfolio. Such conditions include, without limitation, credit quality indicators such as amounts and percentages of loans classified as past due, criticized and non-performing, conditions internal to the Bank such as the skill and experience of lending and credit personnel and effectiveness of credit review processes, the rate of portfolio growth, the extent of hold limits and loan concentrations, such as loans to specific borrowers, loans to groups of affiliated borrowers, loans to borrowers in defined industry groups and loans to borrowers, and collateral, in defined geographic locations. Conditions external to the Bank that may impact incurred losses that are also considered by management in the evaluation of the allowance include the general health of the national economy and regional economies where the Bank operates, international economic conditions, domestic and international political events that may impact the Bank’s loan portfolio, regulatory developments deemed relevant to risk assessment and classification of credits and circumstances that may have negative consequences for industries or specific borrowers where the Bank has exposure. Management’s assessment of the allowance begins with a review of historical credit loss experience as a baseline before consideration of current environmental issues both internal and external to the Bank that might reasonably cause the measure of incurred loss to differ from historical experience. The Bank’s allowance methodology employs a loss migration technique to determine historical loss percentages applicable to all defined credit risk grades. The methodology also calculates historical loss percentages by portfolio segment and computes segment weights as a measure of the relative risk of loans in each segment compared to the entire portfolio. These processes allow for a continuous review of not only absolute historical loss percentages but also an assessment of credit risk grade migration, positive and negative, and changes in portfolio composition as defined by portfolio segment. Management has identified certain measures that are believed to offer guidance as leading, concurrent and trailing indicators respectively of general economic health that in turn are thought to be relevant to the measure of incurred loss in the Bank’s loan portfolio. These together with other internal and external risk elements have been individually quantified and collectively compiled into an aggregate range of adjustment from which management selects a single qualitative factor ("Q Factor"). This Q Factor is added or subtracted from historical loss rates, as relevant, to compute an appropriate reserve based upon actual portfolio composition as defined by portfolio segment and credit risk grade composition. By compiling identified risk elements into a range of possible adjustment and selection by management of a single factor from the range, management minimizes the risk of over-adjusting historical loss rates for changes in multiple contributing elements that may individually be signaling the same change in incurred loss. The specific Q Factor adjustment and application of any management overlay to model calculated segment weights reflects management’s determination that the allowance model is calculating an appropriate level of the allowance in the context of all known loan portfolio quality and concentration issues as well as other environmental factors that are reasonably believed to cause the measure of incurred loss, inclusive of unidentified losses inherent in the current portfolio, to differ from historical experience. Because credit risk grade migration, both positive and negative, can significantly trail triggering events such as change in economic conditions, commodity prices or interest rates or changes in collateral values or changes in regulatory interpretation or application of laws or standards impacting the Bank’s lending activities, management’s interpretation of the collective impact of all such issues on incurred loss guides management’s selection of an appropriate Q Factor adjustment. The additional qualitative reserve component of the allowance that is not derived by the allowance allocation percentages compensates for the uncertainty and complexity in estimating loan and lease losses associated with circumstances or events that are out of the ordinary, not predictable in amount or frequency or not reasonably correlated with either past experience and/or general economic conditions. Examples of such events include natural disasters such as hurricanes and borrower fraud through act or omission in delivery of accurate financial reporting or certification of collateral value. These situations, while not common, do not necessarily correlate well 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 such unpredictable events. The methodology used in the periodic review of the appropriateness of the allowance, which is performed at least quarterly, is designed to be dynamic and responsive to changes in portfolio credit quality. Changes are reflected in the general allowance, in specific reserves as the collectability of classified loans is evaluated with new information and in the additional qualitative reserve. As our portfolio has matured, historical loss ratios have been closely monitored. Our reserve appropriateness relies primarily on our loss history, supplemented by our additional qualitative reserve. The review of the appropriateness of the allowance is performed by executive management and presented to the audit and risk committees of our board of directors for their review. The committees report to the board as part of the board's review on a quarterly basis of the Company's consolidated financial statements.
Other Real Estate Owned	Other Real Estate Owned Other real estate owned (“OREO”), which is included in other assets on the consolidated balance sheet, consists of real estate that has been foreclosed. 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 through a charge to the allowance for loan losses, if necessary. Subsequent write-downs required for declines in value are recorded through a valuation allowance, or taken directly to the asset, and are recorded in allowance and other carrying costs for OREO in the consolidated statements of income and other comprehensive income. Gains or losses on sale of OREO are recorded in other non-interest income in the consolidated statements of income and other comprehensive income.
Mortgage Servicing Rights	Mortgage Servicing Rights, Net Mortgage servicing rights ("MSRs") are created by selling mortgage loans with servicing rights retained. We identify classes of servicing rights based upon the nature of the underlying assumptions used to value the asset along with the risks associated with the underlying asset. Based upon these criteria we have one class of MSRs, residential. MSRs are recognized based on the estimated fair value of the mortgage loans and the related servicing rights at the date of sale using values derived from a valuation model. MSRs are reported on the consolidated balance sheets at amortized cost, less a valuation allowance if the fair value of identified strata within the MSR portfolio are determined to have a fair value that is less than amortized cost. MSRs are amortized proportionally over the estimated life of the projected net servicing revenue and are periodically evaluated for impairment. Loan servicing fee income represents income earned for servicing mortgage loans owned by investors and includes mortgage servicing fees and other ancillary servicing income. Servicing fees are recorded as income when earned and are reported in non-interest income on the consolidated statements of income and other comprehensive income. MSR valuation allowance expense and servicing related expenses are recorded in servicing related expenses in the consolidated statements of income and other comprehensive income.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets, Net Intangible assets are acquired assets that lack physical substance but can be distinguished from goodwill because of contractual or other legal rights or because the asset is capable of being sold or exchanged either on its own or in combination with a related contract, asset, or liability. Our intangible assets relate primarily to loan customer relationships purchased as part of business acquisitions. Intangible assets with definite useful lives are amortized over their estimated life. Goodwill and intangible assets are tested for impairment at least annually or whenever changes in circumstances indicate the carrying amount of the assets may not be recoverable from future undiscounted cash flows. If impaired, the assets are recorded at fair value.
Premises and Equipment	Premises and Equipment, Net Premises and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets. Furniture and equipment is generally depreciated over three to five years , while leasehold improvements are generally depreciated over the term of their respective lease. Gains or losses on disposals of premises and equipment are included in other non-interest income in the consolidated statements of income and other comprehensive income.
Software	Software Costs incurred in connection with development or purchase of internal use software and cloud computing arrangements, including an in-substance software license, are capitalized. Amortization is computed on a straight-line basis over the estimated useful life of the asset, which generally range from one to five years . Capitalized internal use software is included in other assets in the consolidated balance sheets.
Financial Instruments with Off-Balance Sheet Risk	Financial Instruments with Off-Balance Sheet Risk The Company has undertaken certain guarantee obligations in the ordinary course of business which include liabilities with off-balance sheet risk. We consider the following arrangements to be guarantees: commitments to extend credit, standby letters of credit and indemnification agreements included within third party contractual arrangements. 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. 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 will include 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 actual losses experienced from actual activity.
Revenue Recognition	Revenue Recognition 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). Payment 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 a third party broker-dealer 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 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, bank owned life insurance income, dividends on FHLB and FRB stock and other general operating income, none of which are subject to the requirements of ASC 606.
Stock-based Compensation	Stock-based Compensation We account for all stock-based compensation transactions in accordance with ASC 718, Compensation — Stock Compensation (“ASC 718”), which requires that stock compensation transactions be recognized as compensation expense in the consolidated statement of income and other comprehensive income based on their fair values on the measurement date, which is the date of the grant.
Income Taxes	Income Taxes The Company and its subsidiary file a consolidated federal income tax return. We utilize the liability method in accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based upon the difference between the values of the assets and liabilities as reflected in the financial statements and their related tax basis using enacted tax rates in effect for the year in which the differences are expected to be recovered or settled. As changes in tax law or rates are enacted, deferred tax assets and liabilities are adjusted through the provision for income taxes. A valuation allowance is provided against deferred tax assets unless it is more likely than not that such deferred tax assets will be realized.
Fair Values of Financial Instruments	Fair Values of Financial Instruments ASC 820, Fair Value Measurements and Disclosures (“ASC 820”), defines fair value, establishes a framework for measuring fair value under GAAP and enhances disclosures about fair value measurements. In general, fair values of financial instruments are based upon quoted market prices, where available. If such quoted market prices are not available, fair value is 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.
Derivative Financial Instruments	Derivative Financial Instruments All contracts that satisfy the definition of a derivative are recorded at fair value in other assets and other liabilities in the consolidated balance sheets. We record the derivatives 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 contracts 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 designed 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.
Segment Reporting	Segment Reporting We have determined that all of our lending divisions and subsidiaries meet the aggregation criteria of ASC 280, Segment Reporting , since all offer similar products and services, operate with similar processes, have similar customers and are collectively reviewed by the chief operating decision maker.

Investment Securities (Tables)

Investment Securities (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Securities, Available-for-sale [Abstract]
Summary of securities	The following is a summary of available-for-sale debt securities: (in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value December 31, 2018 Available-for-sale debt securities: Residential mortgage-backed securities $ 6,874 $ 368 $ — $ 7,242 Tax-exempt asset-backed securities 95,518 286 — 95,804 $ 102,392 $ 654 $ — $ 103,046 December 31, 2017 Available-for-sale debt securities: 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) Less Than One Year After One Through Five Years After Five Through Ten Years After Ten Years Total December 31, 2018 Available-for-sale: Residential mortgage-backed securities:(1) Amortized cost $ 3 $ 1,573 $ — $ 5,298 $ 6,874 Estimated fair value 4 1,668 — 5,570 7,242 Weighted average yield(3) 6.50 % 5.54 % — % 4.53 % 4.76 % Tax-exempt asset-backed securities:(1) Amortized Cost — — — 95,518 95,518 Estimated fair value — — — 95,804 95,804 Weighted average yield(2)(3) — % — % — % 4.25 % 4.25 % Total available-for-sale debt securities: Amortized cost $ 102,392 Estimated fair value $ 103,046 December 31, 2017 Available-for-sale: 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/(losses) recognized in net income on equity securities	The following is a summary of unrealized and realized gains/(losses) recognized in net income on equity securities: Year Ended (in thousands) Net gains/(losses) recognized during the period $ (975 ) Less: Realized net gains/(losses) recognized during the period on equity securities sold 460 Unrealized net gains/(losses) recognized during the period on equity securities still held $ (1,435 )

Loans Held for Investment and_2

Loans Held for Investment and Allowance for Loan Losses (Tables)	12 Months Ended
	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract]
Schedule of loans held for investments	Loans held for investment are summarized by portfolio segment as follows: December 31, (in thousands) 2018 2017 Commercial $ 10,373,288 $ 9,189,811 Mortgage finance 5,877,524 5,308,160 Construction 2,120,966 2,166,208 Real estate 3,929,117 3,794,577 Consumer 63,438 48,684 Equipment leases 312,191 264,903 Gross loans held for investment 22,676,524 20,772,343 Deferred income (net of direct origination costs) (108,450 ) (97,931 ) Allowance for loan losses (191,522 ) (184,655 ) Total loans held for investment, net $ 22,376,552 $ 20,489,757
Schedule of the credit risk profile of loan portfolio by internally assigned grades and nonaccrual status	The following tables summarize the credit risk profile of our loans held for investment by internally assigned grades and non-accrual status: (in thousands) Commercial Mortgage Finance Construction Real Estate Consumer Equipment Leases Total December 31, 2018 Grade: Pass $ 10,034,597 $ 5,877,524 $ 2,099,955 $ 3,850,811 $ 61,815 $ 309,775 $ 22,234,477 Special mention 120,531 — 21,011 47,644 — 2,223 191,409 Substandard-accruing 140,297 — — 28,205 1,568 193 170,263 Non-accrual 77,863 — — 2,457 55 — 80,375 Total loans held for investment $ 10,373,288 $ 5,877,524 $ 2,120,966 $ 3,929,117 $ 63,438 $ 312,191 $ 22,676,524 December 31, 2017 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	Allocation of a portion of the allowance to one category of loans does not preclude its availability to absorb losses in other categories. (in thousands) Commercial Mortgage Finance Construction Real Estate Consumer Equipment Leases Additional Qualitative Reserve Total Year ended December 31, 2018 Allowance for loan losses: Beginning balance $ 118,806 $ — $ 19,273 $ 34,287 $ 357 $ 3,542 $ 8,390 $ 184,655 Provision for loan losses 87,860 — (31 ) (1,003 ) 397 (1,427 ) (1,159 ) 84,637 Charge-offs 79,692 — — — 767 319 — 80,778 Recoveries 2,468 — — 69 438 33 — 3,008 Net charge-offs (recoveries) 77,224 — — (69 ) 329 286 — 77,770 Ending balance $ 129,442 $ — $ 19,242 $ 33,353 $ 425 $ 1,829 $ 7,231 $ 191,522 Period end allowance for loan losses allocated to: Loans individually evaluated for impairment $ 8,252 $ — $ — $ 48 $ 10 $ — $ — $ 8,310 Loans collectively evaluated for impairment 121,190 — 19,242 33,305 415 1,829 7,231 183,212 Total $ 129,442 $ — $ 19,242 $ 33,353 $ 425 $ 1,829 $ 7,231 $ 191,522 Period end loans allocated to: Loans individually evaluated for impairment $ 78,428 $ — $ — $ 8,857 $ 55 $ — $ — $ 87,340 Loans collectively evaluated for impairment 10,294,860 5,877,524 2,120,966 3,920,260 63,383 312,191 — 22,589,184 Total $ 10,373,288 $ 5,877,524 $ 2,120,966 $ 3,929,117 $ 63,438 $ 312,191 $ — $ 22,676,524 Year ended December 31, 2017 Allowance for loan losses: Beginning balance $ 128,768 $ — $ 13,144 $ 19,149 $ 241 $ 1,124 $ 5,700 $ 168,126 Provision for loan losses 19,590 — 6,084 15,353 226 2,408 2,690 46,351 Charge-offs 34,145 — 59 290 180 — — 34,674 Recoveries 4,593 — 104 75 70 10 — 4,852 Net charge-offs (recoveries) 29,552 — (45 ) 215 110 (10 ) — 29,822 Ending balance $ 118,806 $ — $ 19,273 $ 34,287 $ 357 $ 3,542 $ 8,390 $ 184,655 Period end allowance for loan losses allocated to: Loans individually evaluated for impairment $ 24,316 $ — $ — $ 101 $ — $ — $ — $ 24,417 Loans collectively evaluated for impairment 94,490 — 19,273 34,186 357 3,542 8,390 160,238 Total $ 118,806 $ — $ 19,273 $ 34,287 $ 357 $ 3,542 $ 8,390 $ 184,655 Period end loans allocated to: 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
Schedule of impaired loans, by portfolio class	The following tables detail our impaired loans held for investment by portfolio segment. In accordance with ASC 310, Receivables , we have also included all restructured and formerly restructured loans in our impaired loan totals. (in thousands) Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized December 31, 2018 With no related allowance recorded: Commercial Business loans $ 23,367 $ 55,008 $ — $ 16,426 $ 133 Energy loans 12,188 13,363 — 17,135 — Construction Market risk — — — — — Real estate Market risk — — — — — Commercial 7,388 7,388 — 3,215 — Secured by 1-4 family 1,233 1,233 — 734 — Consumer — — — — — Equipment leases — — — — — Total impaired loans with no allowance recorded $ 44,176 $ 76,992 $ — $ 37,510 $ 133 With an allowance recorded: Commercial Business loans $ 17,529 $ 17,564 $ 4,679 $ 41,307 $ — Energy loans 25,344 28,105 3,573 25,672 — Construction Market risk — — — — — Real estate Market risk — — — 49 — Commercial — — — 83 — Secured by 1-4 family 236 236 48 188 — Consumer 55 55 10 54 — Equipment leases — — — 275 — Total impaired loans with an allowance recorded $ 43,164 $ 45,960 $ 8,310 $ 67,628 $ — Combined: Commercial Business loans $ 40,896 $ 72,572 $ 4,679 $ 57,733 $ 133 Energy loans 37,532 41,468 3,573 42,807 — Construction Market risk — — — — — Real estate Market risk — — — 49 — Commercial 7,388 7,388 — 3,298 — Secured by 1-4 family 1,469 1,469 48 922 — Consumer 55 55 10 54 — Equipment leases — — — 275 — Total impaired loans $ 87,340 $ 122,952 $ 8,310 $ 105,138 $ 133 (in thousands) Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized December 31, 2017 With no related allowance recorded: Commercial Business loans $ 16,835 $ 18,257 $ — $ 22,964 $ — Energy loans 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 — — — — — Equipment 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 loans 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 — Equipment 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 loans 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 — Equipment 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: (in thousands) 30-59 Days Past Due 60-89 Days Past Due Greater Than 90 Days(1) Total Past Due Non-accrual Current Total December 31, 2018 Commercial Business loans $ 16,845 $ 13,680 $ 9,163 $ 39,688 $ 40,331 $ 8,662,285 $ 8,742,304 Energy — 1,150 — 1,150 37,532 1,592,302 1,630,984 Mortgage finance loans — — — — — 5,877,524 5,877,524 Construction Market risk — 2,551 — 2,551 — 2,028,062 2,030,613 Commercial — — — — — 64,957 64,957 Secured by 1-4 family 59 — — 59 — 25,337 25,396 Real estate Market risk 1,738 — — 1,738 — 2,786,299 2,788,037 Commercial 1,643 4,595 — 6,238 988 776,232 783,458 Secured by 1-4 family 1,484 44 190 1,718 1,469 354,435 357,622 Consumer — — — — 55 63,383 63,438 Equipment leases 256 — — 256 — 311,935 312,191 Total loans held for investment $ 22,025 $ 22,020 $ 9,353 $ 53,398 $ 80,375 $ 22,542,751 $ 22,676,524 (1) Loans past due 90 days and still accruing includes premium finance loans of $9.2 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 details the recorded investment at December 31, 2018 and 2017 of loans that have been restructured during the years ended December 31, 2018 and 2017 by type of modification: Extended Maturity Adjusted Payment Schedule Total (in thousands, except number of contracts) Number of Contracts Balance at Period End Number of Contracts Balance at Period End Number of Contracts Balance at Period End Year Ended December 31, 2018 Commercial Business loans — $ — 2 $ 2,411 2 $ 2,411 Energy loans — — 5 10,047 5 10,047 Total — $ — 7 $ 12,458 $ 7 $ 12,458 Year Ended December 31, 2017 Commercial Business loans 1 $ 712 2 $ 6,928 $ 3 $ 7,640 Energy loans 1 — — — 1 — Total 2 $ 712 2 $ 6,928 $ 4 $ 7,640

OREO and Valuation Allowance _2

OREO and Valuation Allowance for Losses on OREO (Tables)	12 Months Ended
	Dec. 31, 2018
Real Estate Owned, Disclosure of Detailed Components [Abstract]
Summary of the activity related to OREO	The table below presents a summary of the activity related to OREO: Year ended December 31, (in thousands) 2018 2017 2016 Beginning balance $ 11,742 $ 18,961 $ 278 Additions — — 18,822 Sales (11,663 ) (1,108 ) (139 ) Valuation allowance for OREO — — — Direct write-downs — (6,111 ) — Ending balance $ 79 $ 11,742 $ 18,961 During 2017, we recorded a $6.1 million write-down on one asset. In 2018, we sold this asset and recorded a $2.0 million gain on sale. The gain on sale was recorded in other non-interest income.

Certain Transfers of Financia_2

Certain Transfers of Financial Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Transfers and Servicing [Abstract]
Schedule of Loans Held-for-sale [Table Text Block]	The table below presents a reconciliation of the changes in loans held for sale: Year Ended December 31, (in thousands) 2018 2017 Outstanding balance: Beginning balance $ 1,012,580 $ 980,414 Loans purchased 6,753,709 5,556,964 Payments and loans sold (5,816,504 ) (5,524,798 ) Ending balance(1) 1,949,785 1,012,580 Fair value adjustment: Beginning balance (1,576 ) 8,333 Increase/(decrease) to fair value 21,265 9,909 Ending balance 19,689 (1,576 ) Loans held for sale at fair value(1) $ 1,969,474 $ 1,011,004 (1) Includes $299,000 and $3.3 million of loans held for sale that are carried at lower of cost or market as of December 31, 2018 and 2017 , respectively.
Schedule of Mortgage Servicing Rights Activity [Table Text Block]	retain the right to service the loans sold through our MCA program, creating MSRs which are recorded as assets on our balance sheet. A summary of MSR activity is as follows: Year Ended December 31, (in thousands) 2018 2017 MSRs: Balance, beginning of year $ 88,150 $ 28,536 Capitalized servicing rights 39,149 67,970 Amortization (9,278 ) (8,356 ) Sales (75,547 ) — Balance, end of period $ 42,474 $ 88,150 Valuation allowance: Balance, beginning of year $ 2,823 $ — Increase in valuation allowance (2,823 ) 2,823 Balance, end of period $ — $ 2,823 MSRs, net(1) $ 42,474 $ 85,327 MSRs, fair value $ 44,502 $ 86,321
Schedule of Fair Value Assumption Used to Value Mortgage Servicing Rights Retained [Table Text Block]	The following summarizes the assumptions used by management to determine the fair value of MSRs: December 31, 2018 2017 Average discount rates 9.55 % 9.90 % Expected prepayment speeds 9.77 % 9.99 % Weighted-average life, in years 7.0 7.0
Schedule of Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets [Table Text Block]	A sensitivity analysis of changes in the fair value of our MSR portfolio resulting from certain key assumptions is presented in the following table: December 31, (in thousands) 2018 2017 50 bp adverse change in prepayment speed $ (6,028 ) $ (11,896 ) 100 bp adverse change in prepayment speed (11,629 ) (28,226 )

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of goodwill and other intangible assets	Goodwill and other intangible assets are summarized as follows: (in thousands) Gross Goodwill and Intangible Assets Accumulated Amortization Net Goodwill and Intangible Assets December 31, 2018 Goodwill $ 15,468 $ (374 ) $ 15,094 Intangible assets—customer relationships and trademarks 9,006 (5,530 ) 3,476 Total goodwill and intangible assets $ 24,474 $ (5,904 ) $ 18,570 December 31, 2017 Goodwill $ 15,468 $ (374 ) $ 15,094 Intangible assets—customer relationships and trademarks 9,006 (5,060 ) 3,946 Total goodwill and intangible assets $ 24,474 $ (5,434 ) $ 19,040
Schedule of estimated aggregate future amortization expense for intangible assets	The estimated aggregate future amortization expense for intangible assets remaining as of December 31, 2018 is as follows: (in thousands) 2019 $ 470 2020 432 2021 405 2022 405 2023 382 Thereafter 1,382 Total $ 3,476

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Summary of premises and equipment	Premises and equipment are summarized as follows: December 31, (in thousands) 2018 2017 Premises $ 27,999 $ 25,790 Furniture and equipment 35,130 32,234 Total cost 63,129 58,024 Accumulated depreciation (39,327 ) (32,848 ) Total premises and equipment, net $ 23,802 $ 25,176
Schedule of minimum future lease payments under operating leases	Minimum future lease payments under operating leases are as follows at December 31, 2018 : (in thousands) Minimum Payments 2019 $ 14,652 2020 15,549 2021 15,846 2022 15,012 2023 14,070 2024 and thereafter 28,666 Total $ 103,795

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2018
Deposits [Abstract]
Schedule of deposits	Deposits are summarized as follows: December 31, (in thousands) 2018 2017 Non-interest-bearing demand deposits $ 7,317,161 $ 7,812,660 Interest-bearing deposits Transaction 3,051,535 2,567,208 Savings 8,222,893 8,214,059 Time 2,014,524 529,253 Total interest-bearing deposits 13,288,952 11,310,520 Total deposits $ 20,606,113 $ 19,123,180
Schedule of maturities of interest-bearing time deposits	The scheduled maturities of interest-bearing time deposits were as follows at December 31, 2018 : (in thousands) 2019 $ 1,990,962 2020 21,894 2021 778 2022 263 2023 127 2024 and after 500 Total $ 2,014,524

Short-Term and Other Borrowin_2

Short-Term and Other Borrowings (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Summary of borrowings	The following table summarizes our short-term and other borrowings: (dollar amounts in thousands) Federal Funds Purchased Customer Repurchase Agreements FHLB Borrowings December 31, 2018 Amount outstanding at year-end $ 629,169 $ 12,005 $ 3,900,000 Interest rate at year-end 2.54 % 0.09 % 2.56 % Average balance outstanding during the year $ 323,140 $ 9,812 $ 1,769,452 Weighted-average interest rate during the year 2.02 % 0.09 % 2.05 % Maximum month-end outstanding during the year $ 629,169 $ 13,835 $ 4,000,000 December 31, 2017 Amount outstanding at year-end $ 359,338 $ 5,702 $ 2,800,000 Interest rate at year-end 1.45 % 0.03 % 1.35 % Average balance outstanding during the year $ 215,895 $ 6,590 $ 1,395,753 Weighted-average interest rate during the year 1.20 % 0.04 % 1.08 % Maximum month-end outstanding during the year $ 544,203 $ 8,727 $ 2,800,000 December 31, 2016 Amount outstanding at year-end $ 101,800 $ 7,775 $ 2,000,000 Interest rate at year-end 0.80 % 0.05 % 0.61 % Average balance outstanding during the year $ 90,904 $ 15,380 $ 1,367,267 Weighted-average interest rate during the year 0.57 % 0.06 % 0.43 % Maximum month-end outstanding during the year $ 263,989 $ 18,884 $ 2,025,000
Summary of other borrowing capacities	The following table summarizes our other borrowing capacities net of balances outstanding. As of December 31, 2018 , all are scheduled to mature within one year. December 31, (in thousands) 2018 2017 2016 FHLB borrowing capacity relating to loans $ 4,568,842 $ 3,890,995 $ 3,057,915 FHLB borrowing capacity relating to securities 721 2,071 1,653 Total FHLB borrowing capacity(1) $ 4,569,563 $ 3,893,066 $ 3,059,568 Unused Federal funds lines available from commercial banks $ 620,000 $ 885,000 $ 1,118,000 Unused Federal Reserve Borrowings capacity $ 4,933,965 $ 4,114,594 $ 3,179,087 Unused revolving line of credit(2) $ 130,000 $ 130,000 $ 130,000 (1) FHLB borrowings are collateralized by a blanket floating lien on certain real estate secured loans, mortgage finance assets and also certain pledged securities. (2) Unsecured revolving, non-amortizing line of credit with maturity date of December 17, 2019. Proceeds may be used for general corporate purposes, including funding regulatory capital infusions into the Bank. The loan agreement contains customary financial covenants and restrictions. No borrowings were made against this line of credit during 2018 or 2017; the average borrowings during the year ended December 31, 2016 were $6.8 million .

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2018
Subordinated Borrowings [Abstract]
Schedule of details of the trust preferred subordinated debentures	As of December 31, 2018 , the details of the trust preferred subordinated debentures are summarized below: (dollar amounts in thousands) Texas Capital Texas Capital Texas Capital Texas Capital Texas Capital Date issued November 19, 2002 April 10, 2003 October 6, 2005 April 28, 2006 September 29, 2006 Trust preferred securities issued $10,310 $10,310 $25,774 $25,774 $41,238 Floating or fixed rate securities Floating Floating Floating Floating Floating Interest rate on subordinated debentures 3 month LIBOR 3 month LIBOR 3 month LIBOR 3 month LIBOR 3 month LIBOR Maturity date November 2032 April 2033 December 2035 June 2036 December 2036

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Schedule of income tax expense/(benefit)	Year ended December 31, (in thousands) 2018 2017 2016 Current: Federal $ 82,556 $ 94,112 $ 86,612 State 3,808 3,257 2,412 Total 86,364 97,369 89,024 Deferred: Federal (6,400 ) 31,276 (2,946 ) State — — — Total (6,400 ) 31,276 (2,946 ) Total expense: Federal 76,156 125,388 83,666 State 3,808 3,257 2,412 Total $ 79,964 $ 128,645 $ 86,078
Schedule of deferred tax assets and liabilities	December 31, (in thousands) 2018 2017 Deferred tax assets: Allowance for credit losses $ 44,224 $ 42,213 Loan origination fees 11,328 10,084 Stock compensation 3,363 4,460 Non-accrual interest 1,724 1,680 Non-qualified deferred compensation 2,211 1,217 Other 2,517 3,380 Total deferred tax assets 65,367 63,034 Deferred tax liabilities: Loan origination costs (2,049 ) (1,304 ) Leases (9,000 ) (6,850 ) MSRs (9,184 ) (17,619 ) Depreciation (8,233 ) (7,354 ) Unrealized gain on securities (138 ) (138 ) Other (2,662 ) (2,068 ) Total deferred tax liabilities (31,266 ) (35,333 ) Net deferred tax asset $ 34,101 $ 27,701
Reconciliation of income attributable to continuing operations	The reconciliation of our effective income tax rate to the U.S. federal statutory tax rate is as follows: Year ended December 31, 2018 2017 2016 U.S. statutory rate 21 % 35 % 35 % State taxes 1 % 1 % 1 % Non-deductible expenses 1 % 1 % 1 % Deferred tax asset remeasurement write-off — % 5 % — % Non-taxable income (1 )% (1 )% (1 )% Other (1 )% (1 )% — % Effective tax rate 21 % 40 % 36 %

Stock-Based Compensation and _2

Stock-Based Compensation and Employee Benefits (Tables)	12 Months Ended
	Dec. 31, 2018
Compensation Related Costs [Abstract]
Schedule of stock appreciation rights activity	A summary of our SAR activity and related information is as follows. These rights are time based and generally vest ratably over a period of five years. December 31, 2018 December 31, 2017 December 31, 2016 SARs Weighted Average Exercise Price SARs Weighted Average Exercise Price SARs Weighted Average Exercise Price SARs outstanding at beginning of year 74,363 $ 30.12 125,863 $ 31.68 360,544 $ 25.73 SARs granted — — — — — — SARs exercised (33,013 ) 31.35 (51,500 ) 33.94 (234,681 ) 22.54 SARs forfeited — — — — — — SARs outstanding at year-end 41,350 $ 29.13 74,363 $ 30.12 125,863 $ 31.68 SARs vested and exercisable at year-end 39,750 $ 27.81 60,463 $ 26.02 94,463 $ 26.73 Weighted average remaining contractual life of SARs vested (in years) 2.33 2.82 3.62 Compensation expense $ 121,000 $ 265,000 $ 307,000 Unrecognized compensation expense $ 6,000 $ 127,000 $ 392,000 Weighted average period over which unrecognized compensation expense is expected to be recognized (in years) 0.17 0.75 1.52 Fair value of shares vested during the year $ 210,807 $ 294,000 $ 337,000 Weighted average remaining contractual life of SARs (in years) 2.44 3.35 4.32 Intrinsic value of SARs exercised $ 925,479 $ 3,802,000 $ 4,881,000
Summary of status and changes in nonvested restricted stock units	ummary of our RSU activity and related information is as follows. Grants of RSUs include both performance-based and time-based vesting conditions and generally vest over a three-year period. December 31, 2018 December 31, 2017 December 31, 2016 RSUs Weighted Average Grant Date Fair Value RSUs Weighted RSUs Weighted RSUs outstanding at beginning of year 423,732 $ 60.01 425,055 $ 51.28 333,174 $ 48.60 RSUs granted 95,891 88.07 121,243 80.40 213,577 51.75 RSUs vested (121,507 ) 54.97 (102,057 ) 48.93 (94,296 ) 42.87 RSUs forfeited (48,583 ) 63.60 (20,509 ) 54.75 (27,400 ) 51.18 RSUs outstanding at year-end 349,533 $ 69.11 423,732 $ 60.01 425,055 $ 51.28 Compensation expense $ 8,803,000 $ 7,790,000 $ 4,771,000 Unrecognized compensation expense $ 16,538,000 $ 18,730,000 $ 17,167,000 Weighted average period over which unrecognized compensation expense is expected to be recognized (in years) 2.90 3.15 3.37 Weighted average remaining contractual life of RSUs (in years) 8.13 8.33 8.65

Financial Instruments with Of_2

Financial Instruments with Off-Balance Sheet Risk (Tables)	12 Months Ended
	Dec. 31, 2018
Risks and Uncertainties [Abstract]
Schedule of financial instruments with off-balance sheet risk	The table below presents our financial instruments with off-balance sheet risk, as well as the activity in the allowance for off-balance sheet credit losses related to those financial instruments. This allowance is recorded in other liabilities on the consolidated balance sheet. Year Ended December 31, (in thousands) 2018 2017 Beginning balance of allowance for off-balance sheet credit losses $ 9,071 $ 11,422 Provision for off-balance sheet credit losses 2,363 (2,351 ) Ending balance of allowance for off-balance sheet credit losses $ 11,434 $ 9,071 Commitments to extend credit - period end balance $ 8,030,198 $ 6,957,847 Standby letters of credit - period end balance $ 236,537 $ 230,958

Regulatory Restrictions (Tables

Regulatory Restrictions (Tables)	12 Months Ended
	Dec. 31, 2018
Regulatory Capital Requirements [Abstract]
Schedule of compliance with Regulatory Capital Requirements	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 (dollars in thousands) Capital Amount Ratio Capital Amount Ratio Capital Amount Ratio Capital Amount Ratio December 31, 2018 CET1 Company $ 2,330,599 8.58 % $ 1,732,501 6.38 % $ 1,902,354 7.00 % N/A N/A Bank 2,340,988 8.62 % 1,731,955 6.38 % 1,901,755 7.00 % 1,765,915 6.50 % Total capital (to risk-weighted assets) Company 3,074,097 11.31 % 2,683,679 9.88 % 2,853,532 10.50 % N/A N/A Bank 2,925,872 10.77 % 2,682,833 9.88 % 2,852,632 10.50 % 2,716,793 10.00 % Tier 1 capital (to risk-weighted assets) Company 2,589,374 9.53 % 2,140,149 7.88 % 2,310,002 8.50 % N/A N/A Bank 2,499,763 9.20 % 2,139,474 7.88 % 2,309,274 8.50 % 2,173,434 8.00 % Tier 1 capital (to average assets)(1) Company 2,589,374 9.87 % 1,049,694 4.00 % 1,049,694 4.00 % N/A N/A Bank 2,499,763 9.53 % 1,049,296 4.00 % 1,049,296 4.00 % 1,311,620 5.00 % 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, 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.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 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: Year ended December 31, (in thousands except per share data) 2018 2017 2016 Numerator: Net income $ 300,824 $ 197,063 $ 155,119 Preferred stock dividends 9,750 9,750 9,750 Net income available to common stockholders $ 291,074 $ 187,313 $ 145,369 Denominator: Denominator for basic earnings per share—weighted average shares 49,936,702 49,587,169 46,239,210 Effect of employee stock-based awards(1) 218,275 239,008 128,228 Effect of warrants to purchase common stock 117,895 433,657 398,464 Denominator for dilutive earnings per share—adjusted weighted average shares and assumed conversions 50,272,872 50,259,834 46,765,902 Basic earnings per common share $ 5.83 $ 3.78 $ 3.14 Diluted earnings per common share $ 5.79 $ 3.73 $ 3.11 (1) SARs and RSUs outstanding of 27,100 , 13,500 and 150,416 in 2018 , 2017 and 2016 , respectively, have not been included in diluted earnings per share because to do so would have been antidilutive for the periods presented.

Fair Value Disclosures (Tables)

Fair Value Disclosures (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Schedule of assets and liabilities measured at fair value	Assets and liabilities measured at fair value are as follows: Fair Value Measurements Using (in thousands) Level 1 Level 2 Level 3 December 31, 2018 Available-for-sale debt securities:(1) Residential mortgage-backed securities $ — $ 7,242 $ — Tax-exempt asset-backed securities — — 95,804 Equity securities(1)(2) 10,262 6,908 — Loans held for sale(3) — 1,952,760 16,415 Loans held for investment(4)(6) — — 29,885 OREO(5)(6) — — 79 Derivative assets(7) — 21,806 — Derivative liabilities(7) — 41,375 — Non-qualified deferred compensation plan liabilities(8) 10,148 — — 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 purchased through our MCA program 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 generally correspond to the fair value of the invested assets, and are measured at fair value on a recurring basis, generally monthly.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	The following table presents a reconciliation of the level 3 fair value category measured at fair value on a recurring basis using Level 3 inputs: Net Realized/Unrealized Gains (Losses) (in thousands) Balance at Beginning of Period Purchases / Additions Sales / Reductions Realized Unrealized Balance at End of Period Year ended December 31, 2018 Tax-exempt asset-backed securities(1) $ — $ 95,521 $ (3 ) $ — $ 286 $ 95,804 Loans held for sale(2) $ — $ 38,430 $ (20,591 ) $ (173 ) $ (1,251 ) $ 16,415 (1) Unrealized gains/(losses) on available-for-sale debt securities are recorded in AOCI. Realized gains/(losses) are recorded in other non-interest income. (2) Realized and unrealized gains/(losses) on loans held for sale are recorded in gain/(loss) on sale of loans held for sale.
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: December 31, 2018 December 31, 2017 (in thousands) Carrying Amount Estimated Fair Value Carrying Estimated Financial assets: Level 1 inputs: Cash and cash equivalents $ 3,080,065 $ 3,080,065 $ 2,905,591 $ 2,905,591 Investment securities 10,262 10,262 5,460 5,460 Level 2 inputs: Investment securities 14,150 14,150 18,051 18,051 Loans held for sale 1,953,059 1,953,059 1,011,004 1,011,004 Derivative assets 21,806 21,806 16,719 16,719 Level 3 inputs: Investment securities 95,804 95,804 — — Loans held for sale 16,415 16,415 — — Loans held for investment, net 22,376,552 22,347,876 20,489,757 20,480,802 Financial liabilities: Level 2 inputs: Federal funds purchased 629,169 629,169 359,338 359,338 Customer repurchase agreements 12,005 12,005 5,702 5,702 Other borrowings 3,900,000 3,900,000 2,800,000 2,800,000 Subordinated notes 281,767 283,349 281,406 285,485 Trust preferred subordinated debentures 113,406 113,406 113,406 113,406 Derivative liabilities 41,375 41,375 17,377 17,377 Level 3 inputs: Deposits 20,606,113 20,608,494 19,123,180 19,124,121

Parent Company Only (Tables)

Parent Company Only (Tables)	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
Balance Sheet	Balance Sheet December 31, (in thousands) 2018 2017 Assets Cash and cash equivalents $ 89,561 $ 144,635 Loans held for investment (net of unearned income) 7,500 7,500 Investment in subsidiaries 2,534,341 2,184,601 Other assets 87,451 86,300 Total assets $ 2,718,853 $ 2,423,036 Liabilities and Stockholders’ Equity Other liabilities $ 1,471 $ 1,244 Subordinated notes 108,614 108,513 Trust preferred subordinated debentures 113,406 113,406 Total liabilities 223,491 223,163 Preferred stock 150,000 150,000 Common stock 502 496 Additional paid-in capital 978,042 971,457 Retained earnings 1,366,308 1,077,500 Treasury stock (8 ) (8 ) Accumulated other comprehensive income 518 428 Total stockholders’ equity 2,495,362 2,199,873 Total liabilities and stockholders’ equity $ 2,718,853 $ 2,423,036
Statement of Earnings	Statement of Earnings Year ended December 31, (in thousands) 2018 2017 2016 Interest on loans $ 3,398 $ 3,271 $ 3,250 Dividend income 10,400 10,400 10,400 Other income 142 108 90 Total income 13,940 13,779 13,740 Other non-interest income 7 13 152 Interest expense 12,031 10,908 10,525 Salaries and employee benefits 588 489 431 Legal and professional 2,020 1,700 1,429 Other non-interest expense 2,013 1,761 1,594 Total expense 16,652 14,858 13,979 Income (loss) before income taxes and equity in undistributed income of subsidiary (2,705 ) (1,066 ) (87 ) Income tax expense (benefit) (587 ) (371 ) (33 ) Income (loss) before equity in undistributed income of subsidiary (2,118 ) (695 ) (54 ) Equity in undistributed income of subsidiary 300,758 194,118 151,445 Net income 298,640 193,423 151,391 Preferred stock dividends 9,750 9,750 9,750 Net income available to common stockholders $ 288,890 $ 183,673 $ 141,641
Statement of Cash Flows	Statements of Cash Flows Year ended December 31, (in thousands) 2018 2017 2016 Operating Activities Net income $ 298,640 $ 193,423 $ 151,391 Adjustments to reconcile net income to net cash used in operating activities: Equity in undistributed income of subsidiary (300,758 ) (194,118 ) (151,445 ) Amortization 101 101 101 Increase in other assets (1,152 ) (739 ) (10 ) Excess tax benefits from stock-based compensation arrangements — — (2,013 ) Increase (decrease) in other liabilities 227 (40 ) 165 Net cash used in operating activities (2,942 ) (1,373 ) (1,811 ) Investing Activities Net increase in loans held for investment — (7,500 ) — Investments in and advances to subsidiaries (40,000 ) (55,000 ) (57,000 ) Net cash used in investing activities (40,000 ) (62,500 ) (57,000 ) Financing Activities Proceeds from sale of stock related to stock-based awards (2,382 ) (2,241 ) (2,481 ) Proceeds from sale of common stock — — 236,467 Preferred dividends paid (9,750 ) (9,750 ) (9,750 ) Excess tax benefits from stock-based compensation arrangements — — 2,013 Net cash provided by (used in) financing activities (12,132 ) (11,991 ) 226,249 Net increase (decrease) in cash and cash equivalents (55,074 ) (75,864 ) 167,438 Cash and cash equivalents at beginning of year 144,635 220,499 53,061 Cash and cash equivalents at end of year $ 89,561 $ 144,635 $ 220,499

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments	The notional amounts and estimated fair values of derivative positions outstanding are presented in the following table: December 31, 2018 December 31, 2017 Estimated Fair Value Estimated Fair Value (in thousands) Notional Amount Asset Derivative Liability Derivative Notional Amount Asset Derivative Liability Derivative Non-hedging derivatives: Financial institution counterparties: Commercial loan/lease interest rate swaps $ 1,579,328 $ 7,978 $ 16,719 $ 1,393,764 $ 4,736 $ 15,482 Commercial loan/lease interest rate caps 606,950 1,109 4 242,700 421 7 Foreign currency forward contracts 39,737 2,263 59 2,466 4 69 Customer counterparties: Commercial loan/lease interest rate swaps 1,579,328 16,719 7,978 1,393,764 15,482 4,736 Commercial loan/lease interest rate caps 606,950 4 1,109 242,700 7 421 Foreign currency forward contracts 39,737 59 2,263 2,466 69 4 Economic hedging interest rate derivatives: Loan purchase commitments 167,984 1,442 6 253,815 635 190 Forward sale commitments 1,928,527 — 21,005 1,086,224 — 1,103 Gross derivatives 29,574 49,143 21,354 22,012 Offsetting derivative assets/liabilities (7,768 ) (7,768 ) (4,635 ) (4,635 ) Net derivatives included in the consolidated balance sheets $ 21,806 $ 41,375 $ 16,719 $ 17,377
Schedule Of Weighted Average Interest Rate Received And Paid	The weighted-average receive and pay interest rates for interest rate swaps outstanding were as follows: December 31, 2018 Weighted-Average Interest Rate December 31, 2017 Weighted-Average Interest Rate Received Paid Received Paid Non-hedging interest rate swaps 4.24 % 4.20 % 3.59 % 4.34 %

Quarterly Financial Data (Table

Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2018
Selected Quarterly Financial Information [Abstract]
Schedule of Quarterly Financial Information	2018 Selected Quarterly Financial Data (in thousands, except per share data) Fourth Third Second First Interest income $ 321,718 $ 301,754 $ 286,852 $ 253,869 Interest expense 81,045 69,579 55,140 43,569 Net interest income 240,673 232,175 231,712 210,300 Provision for credit losses 35,000 13,000 27,000 12,000 Net interest income after provision for credit losses 205,673 219,175 204,712 198,300 Non-interest income 15,280 25,518 17,279 19,947 Non-interest expense 129,862 136,143 132,131 126,960 Income before income taxes 91,091 108,550 89,860 91,287 Income tax expense 19,200 22,998 18,424 19,342 Net income 71,891 85,552 71,436 71,945 Preferred stock dividends 2,437 2,438 2,437 2,438 Net income available to common stockholders $ 69,454 $ 83,114 $ 68,999 $ 69,507 Basic earnings per share: $ 1.38 $ 1.66 $ 1.39 $ 1.40 Diluted earnings per share: $ 1.38 $ 1.65 $ 1.38 $ 1.38 2017 Selected Quarterly Financial Data (in thousands, except per share data) Fourth Third Second First Interest income $ 249,519 $ 237,643 $ 208,191 $ 183,946 Interest expense 38,870 33,282 25,232 20,587 Net interest income 210,649 204,361 182,959 163,359 Provision for credit losses 2,000 20,000 13,000 9,000 Net interest income after provision for credit losses 208,649 184,361 169,959 154,359 Non-interest income 19,374 19,003 18,769 17,110 Non-interest expense 133,138 114,830 111,814 106,094 Income before income taxes 94,885 88,534 76,914 65,375 Income tax expense 50,143 29,850 25,819 22,833 Net income 44,742 58,684 51,095 42,542 Preferred stock dividends 2,437 2,438 2,437 2,438 Net income available to common stockholders $ 42,305 $ 56,246 $ 48,658 $ 40,104 Basic earnings per share: $ 0.85 $ 1.13 $ 0.98 $ 0.81 Diluted earnings per share: $ 0.84 $ 1.12 $ 0.97 $ 0.80

Operations and Summary of Sig_3

Operations and Summary of Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2018
Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Useful life	1 year
Maximum
Property, Plant and Equipment [Line Items]
Useful life	5 years
Useful life	5 years

Investment Securities (Details)

Investment Securities (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost		$ 102,392
Gross Unrealized Gains		654
Gross Unrealized Losses		0
Estimated Fair Value		103,046
Payments to acquire AFS securities, debt		101,558	$ 97,776	$ 1,760
Residential mortgage-backed securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost		6,874	10,297
Gross Unrealized Gains		368	648
Gross Unrealized Losses		0	0
Estimated Fair Value		7,242	$ 10,945
Tax-exempt asset-backed securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost		95,518
Gross Unrealized Gains		286
Gross Unrealized Losses		0
Estimated Fair Value		$ 95,804
Payments to acquire AFS securities, debt	$ 95,500

Investment Securities (Details

Investment Securities (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Amortized cost
Amortized Cost	$ 102,392
Estimated fair value
Total	103,046
Investment securities	$ 103,046
Available-for-sale Securities, Other Disclosure Items
Federal tax rate (percent)	21.00%	35.00%	35.00%
Customer repurchase agreements
Available-for-sale Securities, Other Disclosure Items
Available-for-sale debt securities pledged to secure certain customer repurchase agreements and deposits	$ 4,800	$ 7,300
Residential mortgage-backed securities
Amortized cost
Less Than One Year	3	409
After One Through Five Years	1,573	819
After Five Through Ten Years	0	1,502
After Ten Years	5,298	7,567
Amortized Cost	6,874	10,297
Estimated fair value
Less Than One Year	4	418
After One Through Five Years	1,668	916
After Five Through Ten Years	0	1,636
After Ten Years	5,570	7,975
Investment securities	$ 7,242	$ 10,945
Weighted average yield
Less Than One Year	6.50%	4.59%
After One Through Five Years	5.54%	6.02%
After Five Through Ten Years	0.00%	5.32%
After Ten Years	4.53%	3.45%
Total	4.76%	3.97%
Tax-exempt asset-backed securities
Amortized cost
Less Than One Year	$ 0
After One Through Five Years	0
After Five Through Ten Years	0
After Ten Years	95,518
Amortized Cost	95,518
Estimated fair value
Less Than One Year	0
After One Through Five Years	0
After Five Through Ten Years	0
After Ten Years	95,804
Investment securities	$ 95,804
Weighted average yield
Less Than One Year	0.00%
After One Through Five Years	0.00%
After Five Through Ten Years	0.00%
After Ten Years	4.25%
Total	4.25%
Deposits
Available-for-sale Securities, Other Disclosure Items
Available-for-sale debt securities pledged to secure certain customer repurchase agreements and deposits	$ 1,700	$ 1,600

Investment Securities (Detail_2

Investment Securities (Details 2) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Abstract]
Estimated fair value	$ 17,200,000	$ 12,600,000
Net unrealized gains reclassified out of AOCI into retained earnings		$ 10,000
Net gains/(losses) recognized during the period	(975,000)
Less: Realized net gains/(losses) recognized during the period on equity securities sold	460,000
Unrealized net gains/(losses) recognized during the period on equity securities still held	$ (1,435,000)

Loans Held for Investment and_3

Loans Held for Investment and Allowance for Loan Losses (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loans and Leases Receivable, Net Reported Amount
Commercial	$ 10,373,288	$ 9,189,811
Mortgage finance	5,877,524	5,308,160
Construction	2,120,966	2,166,208
Real estate	3,929,117	3,794,577
Consumer	63,438	48,684
Equipment leases	312,191	264,903
Gross loans held for investment	22,676,524	20,772,343
Deferred income (net of direct origination costs)	(108,450)	(97,931)
Allowance for loan losses	(191,522)	(184,655)	$ (168,126)
Loans held for investment, net	$ 22,376,552	$ 20,489,757

Loans Held for Investment and_4

Loans Held for Investment and Allowance for Loan Losses (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Additional qualitative reserve as percentage of loans held for investment	0.03%	0.04%
Average impaired loans outstanding	$ 105,138	$ 130,777	$ 174,100
Interest income recognized on non-accrual loans	100	0	100
Interest lost on non-accrual loans	8,500	19,000	$ 7,900
Non-accrual loans earning on cash basis	0
Nonaccrual loans that met the criteria for restructured	$ 20,000	$ 18,800

Loans Held for Investment and_5

Loans Held for Investment and Allowance for Loan Losses (Details 2) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Commercial	$ 10,373,288	$ 9,189,811
Mortgage finance	5,877,524	5,308,160
Construction	2,120,966	2,166,208
Real estate	3,929,117	3,794,577
Consumer	63,438	48,684
Equipment leases	312,191	264,903
Total	22,676,524	20,772,343
Pass
Financing Receivable, Recorded Investment [Line Items]
Commercial	10,034,597	8,967,471
Mortgage finance	5,877,524	5,308,160
Construction	2,099,955	2,152,654
Real estate	3,850,811	3,706,541
Consumer	61,815	48,591
Equipment leases	309,775	249,865
Total	22,234,477	20,433,282
Special mention
Financing Receivable, Recorded Investment [Line Items]
Commercial	120,531	19,958
Mortgage finance	0	0
Construction	21,011	13,554
Real estate	47,644	53,652
Consumer	0	0
Equipment leases	2,223	495
Total	191,409	87,659
Substandard-accruing
Financing Receivable, Recorded Investment [Line Items]
Commercial	140,297	102,651
Mortgage finance	0	0
Construction	0	0
Real estate	28,205	32,671
Consumer	1,568	93
Equipment leases	193	14,543
Total	170,263	149,958
Non-accrual
Financing Receivable, Recorded Investment [Line Items]
Commercial	77,863	99,731
Mortgage finance	0	0
Construction	0	0
Real estate	2,457	1,713
Consumer	55	0
Equipment leases	0	0
Total	$ 80,375	$ 101,444

Loans Held for Investment and_6

Loans Held for Investment and Allowance for Loan Losses (Details 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 184,655	$ 168,126
Provision for loan losses	84,637	46,351
Charge-offs	80,778	34,674
Recoveries	3,008	4,852
Net charge-offs (recoveries)	77,770	29,822
Ending balance	191,522	184,655
Period end allowance for loan losses allocated to:
Loans individually evaluated for impairment	8,310	24,417
Loans collectively evaluated for impairment	183,212	160,238
Period end loans allocated to:
Loans individually evaluated for impairment	87,340	102,684
Loans collectively evaluated for impairment	22,589,184	20,669,659
Gross loans held for investment	$ 22,676,524	$ 20,772,343
Additional qualitative reserve as percentage of loans held for investment	0.03%	0.04%
Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 118,806	$ 128,768
Provision for loan losses	87,860	19,590
Charge-offs	79,692	34,145
Recoveries	2,468	4,593
Net charge-offs (recoveries)	77,224	29,552
Ending balance	129,442	118,806
Period end allowance for loan losses allocated to:
Loans individually evaluated for impairment	8,252	24,316
Loans collectively evaluated for impairment	121,190	94,490
Period end loans allocated to:
Loans individually evaluated for impairment	78,428	100,676
Loans collectively evaluated for impairment	10,294,860	9,089,135
Gross loans held for investment	10,373,288	9,189,811
Mortgage Finance
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	0	0
Provision for loan losses	0	0
Charge-offs	0	0
Recoveries	0	0
Net charge-offs (recoveries)	0	0
Ending balance	0	0
Period end allowance for loan losses allocated to:
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	0	0
Period end loans allocated to:
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	5,877,524	5,308,160
Gross loans held for investment	5,877,524	5,308,160
Construction
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	19,273	13,144
Provision for loan losses	(31)	6,084
Charge-offs	0	59
Recoveries	0	104
Net charge-offs (recoveries)	0	(45)
Ending balance	19,242	19,273
Period end allowance for loan losses allocated to:
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	19,242	19,273
Period end loans allocated to:
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	2,120,966	2,166,208
Gross loans held for investment	2,120,966	2,166,208
Real Estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	34,287	19,149
Provision for loan losses	(1,003)	15,353
Charge-offs	0	290
Recoveries	69	75
Net charge-offs (recoveries)	(69)	215
Ending balance	33,353	34,287
Period end allowance for loan losses allocated to:
Loans individually evaluated for impairment	48	101
Loans collectively evaluated for impairment	33,305	34,186
Period end loans allocated to:
Loans individually evaluated for impairment	8,857	2,008
Loans collectively evaluated for impairment	3,920,260	3,792,569
Gross loans held for investment	3,929,117	3,794,577
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	357	241
Provision for loan losses	397	226
Charge-offs	767	180
Recoveries	438	70
Net charge-offs (recoveries)	329	110
Ending balance	425	357
Period end allowance for loan losses allocated to:
Loans individually evaluated for impairment	10	0
Loans collectively evaluated for impairment	415	357
Period end loans allocated to:
Loans individually evaluated for impairment	55	0
Loans collectively evaluated for impairment	63,383	48,684
Gross loans held for investment	63,438	48,684
Equipment Leases
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	3,542	1,124
Provision for loan losses	(1,427)	2,408
Charge-offs	319	0
Recoveries	33	10
Net charge-offs (recoveries)	286	(10)
Ending balance	1,829	3,542
Period end allowance for loan losses allocated to:
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	1,829	3,542
Period end loans allocated to:
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	312,191	264,903
Gross loans held for investment	312,191	264,903
Additional Qualitative Reserve
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	8,390	5,700
Provision for loan losses	(1,159)	2,690
Charge-offs	0	0
Recoveries	0	0
Net charge-offs (recoveries)	0	0
Ending balance	7,231	8,390
Period end allowance for loan losses allocated to:
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	7,231	8,390
Period end loans allocated to:
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	0	0
Gross loans held for investment	$ 0	$ 0

Loans Held for Investment and_7

Loans Held for Investment and Allowance for Loan Losses (Details 6) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Recorded Investment
With No Related Allowanced Recorded, Recorded Investment	$ 44,176	$ 39,357
With An Allowanced Recorded, Recorded Investment	43,164	63,327
Combined, Recorded Investment	87,340	102,684
Unpaid Principal Balance
With No Related Allowanced Recorded, Unpaid Principal Balance	76,992	41,955
With An Allowanced Recorded, Unpaid Principal Balance	45,960	75,807
Combined, Unpaid Principal Balance	122,952	117,762
Related Allowance	8,310	24,417
Average Recorded Investment
With No Related Allowanced Recorded, Average Recorded Investment	37,510	61,709
With An Allowanced Recorded, Average Recorded Investment	67,628	69,068
Combined, Average Recorded Investment	105,138	130,777	$ 174,100
Interest Income Recognized
With No Related Allowanced Recorded, Interest Income Recognized	133	0
With An Allowanced Recorded, Interest Income Recognized	0	6
Interest income recognized on non-accrual loans	100	0	$ 100
Commercial | Business loans
Recorded Investment
With No Related Allowanced Recorded, Recorded Investment	23,367	16,835
With An Allowanced Recorded, Recorded Investment	17,529	18,645
Combined, Recorded Investment	40,896	35,480
Unpaid Principal Balance
With No Related Allowanced Recorded, Unpaid Principal Balance	55,008	18,257
With An Allowanced Recorded, Unpaid Principal Balance	17,564	19,020
Combined, Unpaid Principal Balance	72,572	37,277
Related Allowance	4,679	2,544
Average Recorded Investment
With No Related Allowanced Recorded, Average Recorded Investment	16,426	22,964
With An Allowanced Recorded, Average Recorded Investment	41,307	16,960
Combined, Average Recorded Investment	57,733	39,924
Interest Income Recognized
With No Related Allowanced Recorded, Interest Income Recognized	133	0
With An Allowanced Recorded, Interest Income Recognized	0	0
Combined, Interest Income Recognized	133	0
Commercial | Energy loans
Recorded Investment
With No Related Allowanced Recorded, Recorded Investment	12,188	21,426
With An Allowanced Recorded, Recorded Investment	25,344	43,770
Combined, Recorded Investment	37,532	65,196
Unpaid Principal Balance
With No Related Allowanced Recorded, Unpaid Principal Balance	13,363	22,602
With An Allowanced Recorded, Unpaid Principal Balance	28,105	55,875
Combined, Unpaid Principal Balance	41,468	78,477
Related Allowance	3,573	21,772
Average Recorded Investment
With No Related Allowanced Recorded, Average Recorded Investment	17,135	36,579
With An Allowanced Recorded, Average Recorded Investment	25,672	50,867
Combined, Average Recorded Investment	42,807	87,446
Interest Income Recognized
With No Related Allowanced Recorded, Interest Income Recognized	0	0
With An Allowanced Recorded, Interest Income Recognized	0	6
Combined, Interest Income Recognized	0	6
Construction | Market risk
Recorded Investment
With No Related Allowanced Recorded, Recorded Investment	0	0
With An Allowanced Recorded, Recorded Investment	0	0
Combined, Recorded Investment	0	0
Unpaid Principal Balance
With No Related Allowanced Recorded, Unpaid Principal Balance	0	0
With An Allowanced Recorded, Unpaid Principal Balance	0	0
Combined, Unpaid Principal Balance	0	0
Related Allowance	0	0
Average Recorded Investment
With No Related Allowanced Recorded, Average Recorded Investment	0	0
With An Allowanced Recorded, Average Recorded Investment	0	27
Combined, Average Recorded Investment	0	27
Interest Income Recognized
With No Related Allowanced Recorded, Interest Income Recognized	0	0
With An Allowanced Recorded, Interest Income Recognized	0	0
Combined, Interest Income Recognized	0	0
Real estate | Market risk
Recorded Investment
With No Related Allowanced Recorded, Recorded Investment	0	0
With An Allowanced Recorded, Recorded Investment	0	295
Combined, Recorded Investment	0	295
Unpaid Principal Balance
With No Related Allowanced Recorded, Unpaid Principal Balance	0	0
With An Allowanced Recorded, Unpaid Principal Balance	0	295
Combined, Unpaid Principal Balance	0	295
Related Allowance	0	6
Average Recorded Investment
With No Related Allowanced Recorded, Average Recorded Investment	0	0
With An Allowanced Recorded, Average Recorded Investment	49	485
Combined, Average Recorded Investment	49	485
Interest Income Recognized
With No Related Allowanced Recorded, Interest Income Recognized	0	0
With An Allowanced Recorded, Interest Income Recognized	0	0
Combined, Interest Income Recognized	0	0
Real estate | Commercial
Recorded Investment
With No Related Allowanced Recorded, Recorded Investment	7,388	1,096
With An Allowanced Recorded, Recorded Investment	0	499
Combined, Recorded Investment	7,388	1,595
Unpaid Principal Balance
With No Related Allowanced Recorded, Unpaid Principal Balance	7,388	1,096
With An Allowanced Recorded, Unpaid Principal Balance	0	499
Combined, Unpaid Principal Balance	7,388	1,595
Related Allowance	0	75
Average Recorded Investment
With No Related Allowanced Recorded, Average Recorded Investment	3,215	2,166
With An Allowanced Recorded, Average Recorded Investment	83	166
Combined, Average Recorded Investment	3,298	2,332
Interest Income Recognized
With No Related Allowanced Recorded, Interest Income Recognized	0	0
With An Allowanced Recorded, Interest Income Recognized	0	0
Combined, Interest Income Recognized	0	0
Real estate | Secured by 1-4 family
Recorded Investment
With No Related Allowanced Recorded, Recorded Investment	1,233	0
With An Allowanced Recorded, Recorded Investment	236	118
Combined, Recorded Investment	1,469	118
Unpaid Principal Balance
With No Related Allowanced Recorded, Unpaid Principal Balance	1,233	0
With An Allowanced Recorded, Unpaid Principal Balance	236	118
Combined, Unpaid Principal Balance	1,469	118
Related Allowance	48	20
Average Recorded Investment
With No Related Allowanced Recorded, Average Recorded Investment	734	0
With An Allowanced Recorded, Average Recorded Investment	188	516
Combined, Average Recorded Investment	922	516
Interest Income Recognized
With No Related Allowanced Recorded, Interest Income Recognized	0	0
With An Allowanced Recorded, Interest Income Recognized	0	0
Combined, Interest Income Recognized	0	0
Consumer
Recorded Investment
With No Related Allowanced Recorded, Recorded Investment	0	0
With An Allowanced Recorded, Recorded Investment	55	0
Combined, Recorded Investment	55	0
Unpaid Principal Balance
With No Related Allowanced Recorded, Unpaid Principal Balance	0	0
With An Allowanced Recorded, Unpaid Principal Balance	55	0
Combined, Unpaid Principal Balance	55	0
Related Allowance	10	0
Average Recorded Investment
With No Related Allowanced Recorded, Average Recorded Investment	0	0
With An Allowanced Recorded, Average Recorded Investment	54	33
Combined, Average Recorded Investment	54	33
Interest Income Recognized
With No Related Allowanced Recorded, Interest Income Recognized	0	0
With An Allowanced Recorded, Interest Income Recognized	0	0
Combined, Interest Income Recognized	0	0
Equipment leases
Recorded Investment
With No Related Allowanced Recorded, Recorded Investment	0	0
With An Allowanced Recorded, Recorded Investment	0	0
Combined, Recorded Investment	0	0
Unpaid Principal Balance
With No Related Allowanced Recorded, Unpaid Principal Balance	0	0
With An Allowanced Recorded, Unpaid Principal Balance	0	0
Combined, Unpaid Principal Balance	0	0
Related Allowance	0	0
Average Recorded Investment
With No Related Allowanced Recorded, Average Recorded Investment	0	0
With An Allowanced Recorded, Average Recorded Investment	275	14
Combined, Average Recorded Investment	275	14
Interest Income Recognized
With No Related Allowanced Recorded, Interest Income Recognized	0	0
With An Allowanced Recorded, Interest Income Recognized	0	0
Combined, Interest Income Recognized	$ 0	$ 0

Loans Held for Investment and_8

Loans Held for Investment and Allowance for Loan Losses (Details 7) $ in Thousands	Dec. 31, 2018USD ($)
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 53,398
Non-accrual	80,375
Current	22,542,751
Total	22,676,524
Premium finance loans past due and still accruing	9,200
Commercial | Business loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	39,688
Non-accrual	40,331
Current	8,662,285
Total	8,742,304
Commercial | Energy loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,150
Non-accrual	37,532
Current	1,592,302
Total	1,630,984
Mortgage Finance
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Non-accrual	0
Current	5,877,524
Total	5,877,524
Construction | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,551
Non-accrual	0
Current	2,028,062
Total	2,030,613
Construction | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Non-accrual	0
Current	64,957
Total	64,957
Construction | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	59
Non-accrual	0
Current	25,337
Total	25,396
Real estate | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,738
Non-accrual	0
Current	2,786,299
Total	2,788,037
Real estate | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,238
Non-accrual	988
Current	776,232
Total	783,458
Real estate | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,718
Non-accrual	1,469
Current	354,435
Total	357,622
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Non-accrual	55
Current	63,383
Total	63,438
Equipment leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	256
Non-accrual	0
Current	311,935
Total	312,191
30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	22,025
30 to 59 Days Past Due | Commercial | Business loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	16,845
30 to 59 Days Past Due | Commercial | Energy loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
30 to 59 Days Past Due | Mortgage Finance
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
30 to 59 Days Past Due | Construction | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
30 to 59 Days Past Due | Construction | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
30 to 59 Days Past Due | Construction | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	59
30 to 59 Days Past Due | Real estate | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,738
30 to 59 Days Past Due | Real estate | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,643
30 to 59 Days Past Due | Real estate | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,484
30 to 59 Days Past Due | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
30 to 59 Days Past Due | Equipment leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	256
60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	22,020
60 to 89 Days Past Due | Commercial | Business loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	13,680
60 to 89 Days Past Due | Commercial | Energy loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,150
60 to 89 Days Past Due | Mortgage Finance
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
60 to 89 Days Past Due | Construction | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,551
60 to 89 Days Past Due | Construction | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
60 to 89 Days Past Due | Construction | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
60 to 89 Days Past Due | Real estate | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
60 to 89 Days Past Due | Real estate | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,595
60 to 89 Days Past Due | Real estate | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	44
60 to 89 Days Past Due | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
60 to 89 Days Past Due | Equipment leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Greater Than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	9,353
Greater Than 90 Days | Commercial | Business loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	9,163
Greater Than 90 Days | Commercial | Energy loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Greater Than 90 Days | Mortgage Finance
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Greater Than 90 Days | Construction | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Greater Than 90 Days | Construction | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Greater Than 90 Days | Construction | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Greater Than 90 Days | Real estate | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Greater Than 90 Days | Real estate | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Greater Than 90 Days | Real estate | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	190
Greater Than 90 Days | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Greater Than 90 Days | Equipment leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 0

Loans Held for Investment and_9

Loans Held for Investment and Allowance for Loan Losses (Details 8) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)loan	Dec. 31, 2017USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of Contracts | loan	7	4
Loans modified as restructured loans | $	$ 12,458	$ 7,640
Extended maturity
Financing Receivable, Modifications [Line Items]
Number of Contracts | loan	0	2
Loans modified as restructured loans | $	$ 0	$ 712
Adjusted payment schedule
Financing Receivable, Modifications [Line Items]
Number of Contracts | loan	7	2
Loans modified as restructured loans | $	$ 12,458	$ 6,928
Commercial | Business loans
Financing Receivable, Modifications [Line Items]
Number of Contracts | loan	2	3
Loans modified as restructured loans | $	$ 2,411	$ 7,640
Commercial | Business loans | Extended maturity
Financing Receivable, Modifications [Line Items]
Number of Contracts | loan	0	1
Loans modified as restructured loans | $	$ 0	$ 712
Commercial | Business loans | Adjusted payment schedule
Financing Receivable, Modifications [Line Items]
Number of Contracts | loan	2	2
Loans modified as restructured loans | $	$ 2,411	$ 6,928
Commercial | Energy loans
Financing Receivable, Modifications [Line Items]
Number of Contracts | loan	5	1
Loans modified as restructured loans | $	$ 10,047	$ 0
Commercial | Energy loans | Extended maturity
Financing Receivable, Modifications [Line Items]
Number of Contracts | loan	0	1
Loans modified as restructured loans | $	$ 0	$ 0
Commercial | Energy loans | Adjusted payment schedule
Financing Receivable, Modifications [Line Items]
Number of Contracts | loan	5	0
Loans modified as restructured loans | $	$ 10,047	$ 0

OREO and Valuation Allowance _3

OREO and Valuation Allowance for Losses on OREO (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Real Estate [Roll Forward]
Beginning balance	$ 11,742	$ 18,961	$ 278
Additions	0	0	18,822
Sales	(11,663)	(1,108)	(139)
Valuation allowance for OREO	0	0	0
Direct write-downs	0	(6,111)	0
Ending balance	79	11,742	18,961
Other real estate owned write-down	$ 0	6,111	$ 0
Gain on sale		$ 2,000

Certain Transfers of Financia_3

Certain Transfers of Financial Assets Certain Transfers of Financial Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Outstanding balance:
Beginning balance	$ 1,012,580	$ 980,414
Loans purchased	6,753,709	5,556,964
Payments and loans sold	5,816,504	5,524,798
Ending balance	1,949,785	1,012,580
Fair value adjustment:
Increase/(decrease) to fair value	21,265	9,909
Loans held for sale	1,969,474	1,011,004
Fair value over (under) outstanding balance	19,689	(1,576)	$ 8,333
Small Business Administration Loans [Member]
Fair value adjustment:
Fair value over (under) outstanding balance	$ 299	$ 3,300

Certain Transfers of Financia_4

Certain Transfers of Financial Assets (Details 1) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loans and Leases Receivable Disclosure [Line Items]
Loans held for sale	$ 1,949,785,000	$ 1,012,580,000	$ 980,414,000
Estimated exposure related to servicing assets	1,600,000	1,300,000
Principal amount outstanding of loans in servicing portfolio	3,900,000,000	7,000,000,000
Escrow deposits related to servicing portfolio	37,900,000	73,400,000
Losses due to repurchase indemnification and make-whole obligations	258,000	31,000
Greater Than 90 Days
Loans and Leases Receivable Disclosure [Line Items]
Loans held for sale	16,800,000	19,700,000
Mortgage servicing rights
Loans and Leases Receivable Disclosure [Line Items]
Impairment charges	2,800,000
Government guarantees | Greater Than 90 Days
Loans and Leases Receivable Disclosure [Line Items]
Loans held for sale	16,000,000	$ 19,000,000
Non-accrual
Loans and Leases Receivable Disclosure [Line Items]
Loans held for sale	$ 0

Certain Transfers of Financia_5

Certain Transfers of Financial Assets (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Valuation Allowance for Impairment of Recognized Servicing Assets, Sales and Disposals [Abstract]
Valuation allowance, beginning balance	$ 1,300
Valuation allowance, ending balance	1,600	$ 1,300
Mortgage Servicing Rights
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Balance, beginning of year	88,150	28,536
Capitalized servicing rights	39,149	67,970
Amortization	(9,278)	(8,356)
Sales	(75,547)	0
Balance, end of period	42,474	88,150
Valuation Allowance for Impairment of Recognized Servicing Assets, Sales and Disposals [Abstract]
Valuation allowance, beginning balance	2,823	0
Increase in valuation allowance	(2,823)	2,823
Valuation allowance, ending balance	0	2,823
MSRs, net	42,474	85,327
Fair value	$ 44,502	$ 86,321

Certain Transfers of Financia_6

Certain Transfers of Financial Assets (Details 3) - Mortgage Servicing Rights	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items]
Average discount rates (percent)	9.55%	9.90%
Expected prepayment speeds (percent)	9.77%	9.99%
Weighted-average life, in years	7 years	7 years

Certain Transfers of Financia_7

Certain Transfers of Financial Assets Certain Transfers of Financial Assets (Details 4) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Transfers and Servicing [Abstract]
50 bp adverse change in prepayment speed	$ (6,028)	$ (11,896)
100 bp adverse change in prepayment speed	$ (11,629)	$ (28,226)

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Goodwill
Gross	$ 15,468	$ 15,468
Accumulated Amortization	(374)	(374)
Net	15,094	15,094
Intangible assets—customer relationships and trademarks
Gross	9,006	9,006
Accumulated Amortization	(5,530)	(5,060)
Net	3,476	3,946
Total goodwill and intangible assets
Gross	24,474	24,474
Accumulated Amortization	(5,904)	(5,434)
Net	$ 18,570	$ 19,040

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets (Details 1) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
2,016	$ 470
2,017	432
2,018	405
2,019	405
2,020	382
Thereafter	1,382
Net	$ 3,476	$ 3,946

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Total intangible assets	$ 18,570	$ 19,040
Amortization expense related to intangible assets	$ 470	$ 472	$ 448

Premises and Equipment (Details

Premises and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summary of premises and equipment
Premises and equipment, gross	$ 63,129	$ 58,024
Accumulated depreciation	(39,327)	(32,848)
Total premises and equipment, net	23,802	25,176
Depreciation, Depletion and Amortization
Depreciation expense	9,000	6,900	$ 6,000
Premises
Summary of premises and equipment
Premises and equipment, gross	27,999	25,790
Furniture and equipment
Summary of premises and equipment
Premises and equipment, gross	$ 35,130	$ 32,234

Premises and Equipment Premises

Premises and Equipment Premises and Equipment (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Rent expense	$ 16,500	$ 14,400	$ 13,700
2,019	14,652
2,020	15,549
2,021	15,846
2,022	15,012
2,023	14,070
2024 and thereafter	28,666
Total	$ 103,795

Deposits (Details)

Deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Non-interest bearing deposits
Non-interest-bearing demand deposits	$ 7,317,161	$ 7,812,660
Interest-bearing deposits
Transaction	3,051,535	2,567,208
Savings	8,222,893	8,214,059
Time	2,014,524	529,253
Total interest-bearing deposits	13,288,952	11,310,520
Total deposits	$ 20,606,113	$ 19,123,180

Deposits (Details 1)

Deposits (Details 1) $ in Thousands	Dec. 31, 2018USD ($)
Scheduled maturities of interest bearing time deposits
2,015	$ 1,990,962
2,016	21,894
2,017	778
2,018	263
2,019	127
2024 and after	500
Interest bearing time deposits, total	$ 2,014,524

Deposits (Details 2)

Deposits (Details 2) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deposits [Abstract]
Deposits from related parties	$ 13.5	$ 13.5
Interest-bearing time deposits of $250,000 or more	$ 270.2	$ 300.5

Short-Term and Other Borrowin_3

Short-Term and Other Borrowings (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Federal funds purchased
Debt Instrument [Line Items]
Amount outstanding at year-end	$ 629,169	$ 359,338	$ 101,800
Interest rate at year-end	2.54%	1.45%	0.80%
Average balance outstanding during the year	$ 323,140	$ 215,895	$ 90,904
Weighted-average interest rate during the year	2.02%	1.20%	0.57%
Maximum outstanding at any month end	$ 629,169	$ 544,203	$ 263,989
Customer repurchase agreements
Debt Instrument [Line Items]
Amount outstanding at year-end	$ 12,005	$ 5,702	$ 7,775
Interest rate at year-end	0.09%	0.03%	0.05%
Average balance outstanding during the year	$ 9,812	$ 6,590	$ 15,380
Weighted-average interest rate during the year	0.09%	0.04%	0.06%
Maximum outstanding at any month end	$ 13,835	$ 8,727	$ 18,884
FHLB borrowings
Debt Instrument [Line Items]
Amount outstanding at year-end	$ 3,900,000	$ 2,800,000	$ 2,000,000
Interest rate at year-end	2.56%	1.35%	0.61%
Average balance outstanding during the year	$ 1,769,452	$ 1,395,753	$ 1,367,267
Weighted-average interest rate during the year	2.05%	1.08%	0.43%
Maximum outstanding at any month end	$ 4,000,000	$ 2,800,000	$ 2,025,000

Short-Term and Other Borrowin_4

Short-Term and Other Borrowings (Details 1) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summary of other borrowing capacities
Total FHLB borrowing capacity	$ 4,569,563,000	$ 3,893,066,000	$ 3,059,568,000
Unused Federal funds lines available from commercial banks	620,000,000	885,000,000	1,118,000,000
Unused Federal Reserve Borrowings capacity	4,933,965,000	4,114,594,000	3,179,087,000
Unused revolving line of credit	130,000,000	130,000,000	130,000,000
Average amount oustanding	0	0	6,800,000
FHLB borrowing capacity relating to loans
Summary of other borrowing capacities
Total FHLB borrowing capacity	4,568,842,000	3,890,995,000	3,057,915,000
FHLB borrowing capacity relating to securities
Summary of other borrowing capacities
Total FHLB borrowing capacity	$ 721,000	$ 2,071,000	$ 1,653,000

Long-Term Debt (Details)

Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Jan. 31, 2014	Sep. 21, 2012
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Trust preferred securities issued	$ 113,406	$ 113,406	$ 175,000	$ 111,000
Stated interest rate			5.25%	6.50%
Trust preferred subordinated debentures
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Total borrowings	$ 113,400

Long-Term Debt (Details 1)

Long-Term Debt (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Jan. 31, 2014	Sep. 21, 2012
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Trust preferred securities issued	$ 113,406	$ 113,406	$ 175,000	$ 111,000
Texas Capital Bancshares Statutory Trust I
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Date issued	Nov. 19, 2002
Trust preferred securities issued	$ 10,310
Floating or fixed rate securities	Floating
Maturity date	Nov. 30, 2032
Texas Capital Bancshares Statutory Trust I | LIBOR
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Interest rate on subordinated debentures	3 month LIBOR + 3.35%
Interest rate on subordinated debentures, spread on variable rate	3.35%
Texas Capital Statutory Trust II
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Date issued	Apr. 10, 2003
Trust preferred securities issued	$ 10,310
Floating or fixed rate securities	Floating
Maturity date	Apr. 30, 2033
Texas Capital Statutory Trust II | LIBOR
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Interest rate on subordinated debentures	3 month LIBOR + 3.25%
Interest rate on subordinated debentures, spread on variable rate	3.25%
Texas Capital Statutory Trust III
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Date issued	Oct. 6, 2005
Trust preferred securities issued	$ 25,774
Floating or fixed rate securities	Floating
Maturity date	Dec. 31, 2035
Texas Capital Statutory Trust III | LIBOR
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Interest rate on subordinated debentures	3 month LIBOR + 1.51%
Interest rate on subordinated debentures, spread on variable rate	1.51%
Texas Capital Statutory Trust IV
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Date issued	Apr. 28, 2006
Trust preferred securities issued	$ 25,774
Floating or fixed rate securities	Floating
Maturity date	Jun. 30, 2036
Texas Capital Statutory Trust IV | LIBOR
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Interest rate on subordinated debentures	3 month LIBOR + 1.60%
Interest rate on subordinated debentures, spread on variable rate	1.60%
Texas Capital Statutory Trust V
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Date issued	Sep. 29, 2006
Trust preferred securities issued	$ 41,238
Floating or fixed rate securities	Floating
Maturity date	Dec. 31, 2036
Texas Capital Statutory Trust V | LIBOR
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Interest rate on subordinated debentures	3 month LIBOR + 1.71%
Interest rate on subordinated debentures, spread on variable rate	1.71%

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Tax impact of TCJA									$ 17,600
Current:
Federal									82,556	$ 94,112	$ 86,612
State									3,808	3,257	2,412
Total									86,364	97,369	89,024
Deferred:
Federal									(6,400)	31,276	(2,946)
State									0	0	0
Total									(6,400)	31,276	(2,946)
Total expense:
Federal									76,156	125,388	83,666
State									3,808	3,257	2,412
Total	$ 19,200	$ 22,998	$ 18,424	$ 19,342	$ 50,143	$ 29,850	$ 25,819	$ 22,833	$ 79,964	$ 128,645	$ 86,078

Income Taxes (Details 1)

Income Taxes (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Tax at U.S. statutory rate	21.00%	35.00%	35.00%
State taxes (percent)	1.00%	1.00%	1.00%
Non-deductible expenses (percent)	1.00%	1.00%	1.00%
Deductible tax asset write-off (percent)	0.00%	5.00%	0.00%
Non-taxable income (percent)	(1.00%)	(1.00%)	(1.00%)
Other (percent)	(1.00%)	(1.00%)	(0.00%)
Total (percent)	21.00%	40.00%	36.00%
Deferred tax assets:
Allowance for credit losses	$ 44,224	$ 42,213
Loan origination fees	11,328	10,084
Stock compensation	3,363	4,460
Non-accrual interest	1,724	1,680
Non-qualified deferred compensation	2,211	1,217
Other	2,517	3,380
Total deferred tax assets	65,367	63,034
Deferred tax liabilities:
Loan origination costs	(2,049)	(1,304)
Leases	(9,000)	(6,850)
MSRs	(9,184)	(17,619)
Depreciation	(8,233)	(7,354)
Unrealized gain on securities	(138)	(138)
Other	(2,662)	(2,068)
Total deferred tax liabilities	(31,266)	(35,333)
Net deferred tax asset	$ 34,101	$ 27,701

Stock-Based Compensation and _3

Stock-Based Compensation and Employee Benefits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employer contribution	$ 9,600,000	$ 8,400,000	$ 6,800,000
Eligible employee contribution, minimum (in percent)	1.00%
Eligible employee contribution, maximum (in percent)	10.00%
Number of shares authorized under the plan	2,550,000
Number of shares available to be issued under the plan	2,121,515
Compensation expense	$ 8,803,000
Compensation cost for all share-based arrangements, net of taxes	9,000,000	8,100,000	$ 5,100,000
Employer discretionary contributions	$ 1,000,000	$ 260,000
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	95,891	121,243	213,577
Compensation expense		$ 7,790,000	$ 4,771,000
Weighted average remaining contractual life of SARs (in years)	8 years 1 month 16 days	8 years 4 months	8 years 7 months 24 days
Weighted average period over which unrecognized compensation expense is expected to be recognized (in years)	2 years 10 months 25 days	3 years 1 month 25 days	3 years 4 months 15 days
SARs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	0	0	0
Compensation expense	$ 121,000	$ 265,000	$ 307,000
Weighted average remaining contractual life of SARs (in years)	2 years 5 months 9 days	3 years 4 months 5 days	4 years 3 months 24 days
Weighted average period over which unrecognized compensation expense is expected to be recognized (in years)	2 months 1 day	9 months	1 year 6 months 7 days
Cash based performance
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of cash-based performance units issued in period	138,773	121,260	224,071
Number of cash-based performance units outstanding	325,719
Cash-based compensation expense	$ 8,000,000	$ 13,900,000	$ 8,500,000
Service based
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	4 years
Minimum | RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	4 years	4 years	4 years
Maximum | RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	5 years	5 years	5 years
Director | RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			0
2006 ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized under the plan	400,000
Number of shares purchased under the plan	143,348	132,285	124,572

Stock-Based Compensation and _4

Stock-Based Compensation and Employee Benefits (Details 3) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Additional Information:
Compensation expense	$ 8,803,000
Unrecognized compensation expense	$ 16,538,000
SARs
SARs
RSUs outstanding at beginning of year	74,363	125,863	360,544
Granted	0	0	0
SARs exercised	(33,013)	(51,500)	(234,681)
SARs forfeited	0	0	0
RSUs outstanding at year-end	41,350	74,363	125,863
Weighted Average Exercise Price
SARs outstanding at beginning of year, weighted average exercise price	$ 30.12	$ 31.68	$ 25.73
SARs granted, weighted average exercise price	0	0	0
SARs exercised, weighted average exercise price	31.35	33.94	22.54
SARs forfeited, weighted average exercise price	0	0	0
SARs outstanding at year end, weighted average exercise price	$ 29.13	$ 30.12	$ 31.68
Additional Information:
SARs vested and exercisable at year-end	39,750	60,463	94,463
SARs vested and exercisable at year end, weighted average exercise price	$ 27.81	$ 26.02	$ 26.73
Weighted average remaining contractual life of SARs vested (in years)	2 years 3 months 29 days	2 years 9 months 27 days	3 years 7 months 12 days
Compensation expense	$ 121,000	$ 265,000	$ 307,000
Unrecognized compensation expense	$ 6,000	$ 127,000	$ 392,000
Weighted average period over which unrecognized compensation expense is expected to be recognized (in years)	2 months 1 day	9 months	1 year 6 months 7 days
Fair value of shares vested during the year	$ 210,807	$ 294,000	$ 337,000
Weighted average remaining contractual life of SARs (in years)	2 years 5 months 9 days	3 years 4 months 5 days	4 years 3 months 24 days
Intrinsic value of SARs exercised	$ 925,479	$ 3,802,000	$ 4,881,000

Stock-Based Compensation and _5

Stock-Based Compensation and Employee Benefits (Details 4) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Weighted- Average Grant- Date Fair Value
Compensation expense	$ 8,803,000
Unrecognized compensation expense	$ 16,538,000
RSUs
Number of Shares
RSUs outstanding at beginning of year	423,732	425,055	333,174
Granted	95,891	121,243	213,577
RSUs exercised	(121,507)	(102,057)	(94,296)
SARs forfeited	(48,583)	(20,509)	(27,400)
RSUs outstanding at year-end	349,533	423,732	425,055
Weighted- Average Grant- Date Fair Value
Balance at beginning of year, weighted average grant-date fair value	$ 60.01	$ 51.28	$ 48.60
Granted, weighted average grant-date fair value	88.07	80.40	51.75
RSUs exercised	54.97	48.93	42.87
Forfeited, weighted average grant-date fair value	63.60	54.75	51.18
Balance at year end, weighted average grant-date fair value	$ 69.11	$ 60.01	$ 51.28
Compensation expense		$ 7,790,000	$ 4,771,000
Unrecognized compensation expense		$ 18,730,000	$ 17,167,000
Weighted average period over which unrecognized compensation expense is expected to be recognized (in years)	2 years 10 months 25 days	3 years 1 month 25 days	3 years 4 months 15 days
Weighted average remaining contractual life of RSUs (in years)	8 years 1 month 16 days	8 years 4 months	8 years 7 months 24 days

Financial Instruments with Of_3

Financial Instruments with Off-Balance Sheet Risk (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Allowance For Off-Balance Sheet Credit Losses [Roll Forward]
Beginning balance of allowance for off-balance sheet credit losses	$ 9,071	$ 11,422
Provision for off-balance sheet credit losses	2,363	(2,351)
Ending balance of allowance for off-balance sheet credit losses	11,434	9,071
Commitments to extend credit
Allowance For Off-Balance Sheet Credit Losses [Roll Forward]
Off-balance sheet liability	8,030,198	6,957,847
Standby letters of credit
Allowance For Off-Balance Sheet Credit Losses [Roll Forward]
Off-balance sheet liability	$ 236,537	$ 230,958

Regulatory Restrictions (Detail

Regulatory Restrictions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Regulatory Capital Requirements [Abstract]
Required reserve balance at the Federal Reserve	$ 157,700	$ 197,300
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Mortgage finance	5,877,524	5,308,160
Mortgage Finance, Average Balance	5,000,000
Common Equity Tier 1 [Abstract]
CET1, actual amount	2,330,599	2,033,830
Total capital (to risk-weighted assets):
Total capital (to risk weighted assets), actual amount	3,074,097	2,768,153
Tier 1 capital (to risk-weighted assets):
Tier 1 capital (to risk-weighted assets), actual amount	2,589,374	2,293,016
Tier 1 capital (to average assets):
Tier 1 capital (to average assets), actual amount	$ 2,589,374	$ 2,293,016
Risk Based Ratios [Abstract]
CET1, actual ratio	8.58%	8.45%
Total capital (to risk weighted assets), actual ratio	11.31%	11.50%
Tier 1 capital (to risk-weighted assets), actual ratio	9.53%	9.52%
Tier 1 capital (to average assets), actual ratio	9.87%	9.15%
Bank
Common Equity Tier 1 [Abstract]
CET1, actual amount	$ 2,340,988	$ 1,992,152
CET1 to be well capitalized under prompt corrective action provisions, amount	1,765,915	1,563,929
Total capital (to risk-weighted assets):
Total capital (to risk weighted assets), actual amount	2,925,872	2,567,961
Total capital (to risk weighted assets) to be well capitalized under prompt corrective action provisions, amount	2,716,793	2,406,044
Tier 1 capital (to risk-weighted assets):
Tier 1 capital (to risk-weighted assets), actual amount	2,499,763	2,151,338
Tier 1 capital (to risk weighted assets) to be well capitalized under prompt corrective action provisions, amount	2,173,434	1,924,835
Tier 1 capital (to average assets):
Tier 1 capital (to average assets), actual amount	2,499,763	2,151,338
Tier 1 capital (to average assets) to be well capitalized under prompt corrective action provisions, amount	$ 1,311,620	$ 1,252,680
Risk Based Ratios [Abstract]
CET1, actual ratio	8.62%	8.28%
CET1 to be well capitalized under prompt corrective action provisions, ratio	6.50%	6.50%
Total capital (to risk weighted assets), actual ratio	10.77%	10.67%
Total capital (to risk weighted assets) to be well capitalized under prompt corrective action provisions, ratio	10.00%	10.00%
Tier 1 capital (to risk-weighted assets), actual ratio	9.20%	8.94%
Tier 1 capital (to risk weighted assets) to be well capitalized under prompt corrective action provisions, ratio	8.00%	8.00%
Tier 1 capital (to average assets), actual ratio	9.53%	8.59%
Tier 1 capital (to average assets) to be well capitalized under prompt corrective action provisions, ratio	5.00%	5.00%
Basel III, Phase-In Schedule
Common Equity Tier 1 [Abstract]
CET1 for capital adequacy purposes, amount	$ 1,732,501	$ 1,384,448
Total capital (to risk-weighted assets):
Total capital (to risk weighted assets) for capital adequacy purposes, amount	2,683,679	2,227,221
Tier 1 capital (to risk-weighted assets):
Tier 1 capital (to risk-weighted assets) for capital adequacy purposes, amount	2,140,149	1,745,659
Tier 1 capital (to average assets):
Tier 1 capital (to average assets) for capital adequacy purposes, amount	$ 1,049,694	$ 1,002,494
Risk Based Ratios [Abstract]
CET1 for capital adequacy purposes, ratio	6.38%	5.75%
Total capital (to risk weighted assets) for capital adequacy purposes, ratio	9.88%	9.25%
Tier 1 capital (to risk-weighted assets) for capital adequacy purposes, ratio	7.88%	7.25%
Tier 1 capital (to average assets) for capital adequacy purposes, ratio	4.00%	4.00%
Basel III, Phase-In Schedule | Bank
Common Equity Tier 1 [Abstract]
CET1 for capital adequacy purposes, amount	$ 1,731,955	$ 1,383,475
Total capital (to risk-weighted assets):
Total capital (to risk weighted assets) for capital adequacy purposes, amount	2,682,833	2,225,591
Tier 1 capital (to risk-weighted assets):
Tier 1 capital (to risk-weighted assets) for capital adequacy purposes, amount	2,139,474	1,744,382
Tier 1 capital (to average assets):
Tier 1 capital (to average assets) for capital adequacy purposes, amount	$ 1,049,296	$ 1,002,144
Risk Based Ratios [Abstract]
CET1 for capital adequacy purposes, ratio	6.38%	5.75%
Total capital (to risk weighted assets) for capital adequacy purposes, ratio	9.88%	9.25%
Tier 1 capital (to risk-weighted assets) for capital adequacy purposes, ratio	7.88%	7.25%
Tier 1 capital (to average assets) for capital adequacy purposes, ratio	4.00%	4.00%
Basel III, Phased-In
Common Equity Tier 1 [Abstract]
CET1 for capital adequacy purposes, amount	$ 1,902,354	$ 1,685,464
Total capital (to risk-weighted assets):
Total capital (to risk weighted assets) for capital adequacy purposes, amount	2,853,532	2,528,196
Tier 1 capital (to risk-weighted assets):
Tier 1 capital (to risk-weighted assets) for capital adequacy purposes, amount	2,310,002	2,046,635
Tier 1 capital (to average assets):
Tier 1 capital (to average assets) for capital adequacy purposes, amount	$ 1,049,694	$ 1,002,494
Risk Based Ratios [Abstract]
CET1 for capital adequacy purposes, ratio	7.00%	7.00%
Total capital (to risk weighted assets) for capital adequacy purposes, ratio	10.50%	10.50%
Tier 1 capital (to risk-weighted assets) for capital adequacy purposes, ratio	8.50%	8.50%
Tier 1 capital (to average assets) for capital adequacy purposes, ratio	4.00%	4.00%
Basel III, Phased-In | Bank
Common Equity Tier 1 [Abstract]
CET1 for capital adequacy purposes, amount	$ 1,901,755	$ 1,684,231
Total capital (to risk-weighted assets):
Total capital (to risk weighted assets) for capital adequacy purposes, amount	2,852,632	2,526,347
Tier 1 capital (to risk-weighted assets):
Tier 1 capital (to risk-weighted assets) for capital adequacy purposes, amount	2,309,274	2,045,138
Tier 1 capital (to average assets):
Tier 1 capital (to average assets) for capital adequacy purposes, amount	$ 1,049,296	$ 1,002,144
Risk Based Ratios [Abstract]
CET1 for capital adequacy purposes, ratio	7.00%	7.00%
Total capital (to risk weighted assets) for capital adequacy purposes, ratio	10.50%	10.50%
Tier 1 capital (to risk-weighted assets) for capital adequacy purposes, ratio	8.50%	8.50%
Tier 1 capital (to average assets) for capital adequacy purposes, ratio	4.00%	4.00%

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Numerator:
Net income	$ 71,891	$ 85,552	$ 71,436	$ 71,945	$ 44,742	$ 58,684	$ 51,095	$ 42,542	$ 300,824	$ 197,063	$ 155,119
Preferred stock dividends	2,437	2,438	2,437	2,438	2,437	2,438	2,437	2,438	9,750	9,750	9,750
Net income available to common stockholders	$ 69,454	$ 83,114	$ 68,999	$ 69,507	$ 42,305	$ 56,246	$ 48,658	$ 40,104	$ 291,074	$ 187,313	$ 145,369
Denominator:
Denominator for basic earnings per share—weighted average shares									49,936,702	49,587,169	46,239,210
Effect of employee stock-based awards									218,275	239,008	128,228
Effect of warrants to purchase common stock									117,895	433,657	398,464
Denominator for dilutive earnings per share—adjusted weighted average shares and assumed conversions									50,272,872	50,259,834	46,765,902
Basic earnings per common share	$ 1.38	$ 1.66	$ 1.39	$ 1.40	$ 0.85	$ 1.13	$ 0.98	$ 0.81	$ 5.83	$ 3.78	$ 3.14
Diluted earnings per common share	$ 1.38	$ 1.65	$ 1.38	$ 1.38	$ 0.84	$ 1.12	$ 0.97	$ 0.80	$ 5.79	$ 3.73	$ 3.11
Stock options excluded from computation of EPS									27,100	13,500	150,416

Fair Value Disclosures (Details

Fair Value Disclosures (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	$ 103,046
Investment securities	103,046
Loans held for sale	1,969,200	$ 1,007,700
OREO	79	11,742	$ 18,961	$ 278
Tax-exempt asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	95,804
Fair value measurements, recurring basis | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0	0
Derivative assets	0	0
Derivative liabilities	0	0
Non-qualified deferred compensation plan liabilities	10,148	5,587
Fair value measurements, recurring basis | Level 1 | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	0	0
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]
Investment securities	0
Fair value measurements, recurring basis | Level 1 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	10,262	5,460
Fair value measurements, recurring basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	1,952,760	1,007,695
Derivative assets	21,806	16,719
Derivative liabilities	41,375	17,377
Non-qualified deferred compensation plan liabilities	0	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]
Investment securities	7,242	10,945
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]
Investment securities	0
Fair value measurements, recurring basis | Level 2 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	6,908	7,106
Fair value measurements, recurring basis | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	16,415	0
Derivative assets	0	0
Derivative liabilities	0	0
Non-qualified deferred compensation plan liabilities	0	0
Fair value measurements, recurring basis | Level 3 | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	0	0
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]
Investment securities	95,804
Fair value measurements, recurring basis | Level 3 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	0	0
Fair value measurements, nonrecurring basis | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	0	0
OREO	0	0
Fair value measurements, nonrecurring basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	0	0
OREO	0	0
Fair value measurements, nonrecurring basis | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	29,885	21,216
OREO	$ 79	$ 11,742

Fair Value Disclosures (Detai_2

Fair Value Disclosures (Details 1) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Tax-exempt asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at Beginning of Period	$ 0
Purchases / Additions	95,521
Sales / Reductions	(3)
Realized	0
Unrealized	286
Balance at End of Period	95,804
Loans held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at Beginning of Period	0
Purchases / Additions	38,430
Sales / Reductions	(20,591)
Realized	(173)
Unrealized	(1,251)
Balance at End of Period	$ 16,415

Fair Value Disclosures (Detai_3

Fair Value Disclosures (Details 2) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Impaired loans
Fair Value Assets Measured On Non Recurring Basis Unobservable Input Reconciliation [Line Items]
Asset measured on nonrecurring basis, carrying value	$ 32,200	$ 32,200
Asset measured on nonrecurring basis, specific valuation allowance	2,300	11,000
Asset measured on nonrecurring basis, reported fair value	29,900	21,200
OREO
Fair Value Assets Measured On Non Recurring Basis Unobservable Input Reconciliation [Line Items]
Asset measured on nonrecurring basis, carrying value	$ 79	$ 11,742
Measurement Input, Discount Rate
Fair Value Assets Measured On Non Recurring Basis Unobservable Input Reconciliation [Line Items]
Asset-Backed Securities, Measurement Input	0.0421
Asset-Backed Securities, Term	9 years 2 months 13 days
Loans Held-for-sale, Measurement Input	0.929

Fair Value Disclosures (Detai_4

Fair Value Disclosures (Details 3) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	$ 103,046
Loans held for sale	1,969,200	$ 1,007,700
Subordinated notes	281,767	281,406
Level 1 | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	10,262	5,460
Level 1 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	3,080,065	2,905,591
Investment securities	10,262	5,460
Level 2 | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	14,150	18,051
Loans held for sale	1,953,059	1,011,004
Derivative assets	21,806	16,719
Federal funds purchased	629,169	359,338
Customer repurchase agreements	12,005	5,702
Other borrowings	3,900,000	2,800,000
Subordinated notes	281,767	281,406
Derivative liabilities	41,375	17,377
Level 2 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	14,150	18,051
Loans held for sale	1,953,059	1,011,004
Derivative assets	21,806	16,719
Federal funds purchased	629,169	359,338
Customer repurchase agreements	12,005	5,702
Other borrowings	3,900,000	2,800,000
Subordinated notes	283,349	285,485
Derivative liabilities	41,375	17,377
Level 3 | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	95,804	0
Loans held for sale	16,415	0
Loans held for investment, net	22,376,552	20,489,757
Deposits	20,606,113	19,123,180
Trust preferred subordinated debentures	113,406	113,406
Level 3 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	95,804	0
Loans held for sale	16,415	0
Loans held for investment, net	22,347,876	20,480,802
Deposits	20,608,494	19,124,121
Trust preferred subordinated debentures	$ 113,406	$ 113,406

Parent Company Only (Details)

Parent Company Only (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 31, 2014	Sep. 21, 2012
Assets
Cash and cash equivalents	$ 3,080,065	$ 2,905,591	$ 2,839,352	$ 1,790,870
Loans held for investment (net of unearned income)	16,690,550	15,366,252
Other assets	626,614	516,239
Total assets	28,257,767	25,075,645
Liabilities and Stockholders’ Equity
Subordinated notes, net	281,767	281,406
Trust preferred subordinated debentures	113,406	113,406			$ 175,000	$ 111,000
Total liabilities	25,757,373	22,872,924
Preferred stock	150,000	150,000
Common stock	502	496
Additional paid-in capital	967,890	961,305
Retained earnings	1,381,492	1,090,500
Treasury stock	(8)	(8)
Accumulated other comprehensive income	518	428
Total stockholders’ equity	2,500,394	2,202,721	2,009,557	1,623,533
Total liabilities and stockholders’ equity	28,257,767	25,075,645
Texas Capital Bancshares, Inc.
Assets
Cash and cash equivalents	89,561	144,635	$ 220,499	$ 53,061
Loans held for investment (net of unearned income)	7,500	7,500
Investment in subsidiaries	2,534,341	2,184,601
Other assets	87,451	86,300
Total assets	2,718,853	2,423,036
Liabilities and Stockholders’ Equity
Other liabilities	1,471	1,244
Subordinated notes, net	108,614	108,513
Trust preferred subordinated debentures	113,406	113,406
Total liabilities	223,491	223,163
Preferred stock	150,000	150,000
Common stock	502	496
Additional paid-in capital	978,042	971,457
Retained earnings	1,366,308	1,077,500
Treasury stock	(8)	(8)
Accumulated other comprehensive income	518	428
Total stockholders’ equity	2,495,362	2,199,873
Total liabilities and stockholders’ equity	$ 2,718,853	$ 2,423,036

Parent Company Only (Details 1)

Parent Company Only (Details 1) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Earnings
Interest on loans									$ 1,124,970	$ 846,292	$ 684,582
Other non-interest income									26,559	15,080	13,704
Interest expense	$ 81,045	$ 69,579	$ 55,140	$ 43,569	$ 38,870	$ 33,282	$ 25,232	$ 20,587	249,333	117,971	63,594
Salaries and employee benefits									291,768	264,231	228,985
Legal and professional									42,990	29,731	23,326
Other non-interest expense									50,890	42,859	37,033
Income tax expense	19,200	22,998	18,424	19,342	50,143	29,850	25,819	22,833	79,964	128,645	86,078
Net income	71,891	85,552	71,436	71,945	44,742	58,684	51,095	42,542	300,824	197,063	155,119
Preferred stock dividends	2,437	2,438	2,437	2,438	2,437	2,438	2,437	2,438	9,750	9,750	9,750
Net income available to common stockholders	$ 69,454	$ 83,114	$ 68,999	$ 69,507	$ 42,305	$ 56,246	$ 48,658	$ 40,104	291,074	187,313	145,369
Texas Capital Bancshares, Inc.
Statement of Earnings
Interest on loans									3,398	3,271	3,250
Dividend income									10,400	10,400	10,400
Other income									142	108	90
Total income									13,940	13,779	13,740
Other non-interest income									7	13	152
Interest expense									12,031	10,908	10,525
Salaries and employee benefits									588	489	431
Legal and professional									2,020	1,700	1,429
Other non-interest expense									2,013	1,761	1,594
Total expense									16,652	14,858	13,979
Income (loss) before income taxes and equity in undistributed income of subsidiary									(2,705)	(1,066)	(87)
Income tax expense									(587)	(371)	(33)
Income before income taxes									(2,118)	(695)	(54)
Equity in undistributed income of subsidiary									300,758	194,118	151,445
Net income									298,640	193,423	151,391
Preferred stock dividends									9,750	9,750	9,750
Net income available to common stockholders									$ 288,890	$ 183,673	$ 141,641

Parent Company Only (Details 2)

Parent Company Only (Details 2) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities
Net income	$ 71,891	$ 85,552	$ 71,436	$ 71,945	$ 44,742	$ 58,684	$ 51,095	$ 42,542	$ 300,824	$ 197,063	$ 155,119
Adjustments to reconcile net income to net cash used in operating activities:
Increase in other assets									(123,542)	(117,116)	(61,832)
Excess tax benefits from stock-based compensation arrangements									0	0	(2,013)
Increase (decrease) in other liabilities									(5,026)	10,289	(2,576)
Net cash provided by (used in) operating activities									(679,715)	132,161	(726,293)
Investing Activities
Net cash used in investing activities									(1,992,746)	(3,215,745)	(850,210)
Financing Activities
Proceeds from sale of common stock									0	0	236,467
Preferred dividends paid									(9,750)	(9,750)	(9,750)
Net other borrowings									1,100,000	800,000	500,000
Excess tax benefits from stock-based compensation arrangements									0	0	2,013
Net cash provided by financing activities									2,846,935	3,149,823	2,624,985
Net increase (decrease) in cash and cash equivalents									174,474	66,239	1,048,482
Cash and cash equivalents at beginning of period				2,905,591				2,839,352	2,905,591	2,839,352	1,790,870
Cash and cash equivalents at end of period	3,080,065				2,905,591				3,080,065	2,905,591	2,839,352
Texas Capital Bancshares, Inc.
Operating activities
Net income									298,640	193,423	151,391
Adjustments to reconcile net income to net cash used in operating activities:
Equity in undistributed income of subsidiary									(300,758)	(194,118)	(151,445)
Amortization									101	101	101
Increase in other assets									(1,152)	(739)	(10)
Excess tax benefits from stock-based compensation arrangements									0	0	(2,013)
Increase (decrease) in other liabilities									227	(40)	165
Net cash provided by (used in) operating activities									(2,942)	(1,373)	(1,811)
Investing Activities
Net increase in loans held for investment									0	(7,500)	0
Investments in and advances to subsidiaries									(40,000)	(55,000)	(57,000)
Net cash used in investing activities									(40,000)	(62,500)	(57,000)
Financing Activities
Costs from issuance of stock related to stock-based awards and warrants									(2,382)	(2,241)	(2,481)
Proceeds from sale of common stock									0	0	236,467
Preferred dividends paid									(9,750)	(9,750)	(9,750)
Excess tax benefits from stock-based compensation arrangements									0	0	2,013
Net cash provided by financing activities									(12,132)	(11,991)	226,249
Net increase (decrease) in cash and cash equivalents									(55,074)	(75,864)	167,438
Cash and cash equivalents at beginning of period				$ 144,635				$ 220,499	144,635	220,499	53,061
Cash and cash equivalents at end of period	$ 89,561				$ 144,635				$ 89,561	$ 144,635	$ 220,499

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Millions	1 Months Ended
	Feb. 28, 2018	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Deposits from related parties		$ 13.5	$ 13.5
Minimum | Director
Related Party Transaction [Line Items]
Transaction processing services fee	$ 0.4
Maximum | Director
Related Party Transaction [Line Items]
Transaction processing services fee	$ 0.6

Derivative Financial Instrume_3

Derivative Financial Instruments (Details 1) - Non-hedging - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Estimated fair value, asset derivative	$ 29,574	$ 21,354
Estimated fair value, liability derivative	49,143	22,012
Offsetting derivative liabilities	(7,768)	(4,635)
Offsetting derivative assets	(7,768)	(4,635)
Net asset derivatives included in the consolidated balance sheets	21,806	16,719
Net liability derivatives included in the consolidated balance sheets	41,375	17,377
Interest rate contract | Loan purchase commitments
Derivative [Line Items]
Notional amount	167,984	253,815
Estimated fair value, asset derivative	1,442	635
Estimated fair value, liability derivative	6	190
Interest rate contract | Loan purchase commitments
Derivative [Line Items]
Notional amount	1,928,527	1,086,224
Estimated fair value, asset derivative	0	0
Estimated fair value, liability derivative	21,005	1,103
Financial institution counterparties | Commercial loan/lease | Interest rate swap
Derivative [Line Items]
Notional amount	1,579,328	1,393,764
Estimated fair value, asset derivative	7,978	4,736
Estimated fair value, liability derivative	16,719	15,482
Financial institution counterparties | Commercial loan/lease | Interest rate cap
Derivative [Line Items]
Notional amount	606,950	242,700
Estimated fair value, asset derivative	1,109	421
Estimated fair value, liability derivative	4	7
Financial institution counterparties | Commercial loan/lease | Foreign currency forward contracts
Derivative [Line Items]
Notional amount	39,737	2,466
Estimated fair value, asset derivative	2,263	4
Estimated fair value, liability derivative	59	69
Customer counterparties | Commercial loan/lease | Interest rate swap
Derivative [Line Items]
Notional amount	1,579,328	1,393,764
Estimated fair value, asset derivative	16,719	15,482
Estimated fair value, liability derivative	7,978	4,736
Customer counterparties | Commercial loan/lease | Interest rate cap
Derivative [Line Items]
Notional amount	606,950	242,700
Estimated fair value, asset derivative	4	7
Estimated fair value, liability derivative	1,109	421
Customer counterparties | Commercial loan/lease | Foreign currency forward contracts
Derivative [Line Items]
Notional amount	39,737	2,466
Estimated fair value, asset derivative	59	69
Estimated fair value, liability derivative	$ 2,263	$ 4

Derivative Financial Instrume_4

Derivative Financial Instruments Derivative Financial Instruments (Details 2) - Non-hedging - Commercial loan/lease - Interest rate swap	Dec. 31, 2018	Dec. 31, 2017
Interest rate received
Derivative [Line Items]
Weighted average fixed interest rate	4.24%	3.59%
Interest rate paid
Derivative [Line Items]
Weighted average fixed interest rate	4.20%	4.34%

Derivative Financial Instrume_5

Derivative Financial Instruments Derivative Financial Instruments (Details 3)	Dec. 31, 2018USD ($)instrument	Dec. 31, 2017USD ($)instrument
Derivative [Line Items]
Cash collateral pledged for derivatives	$ 25,300,000	$ 15,200,000
Risk participation agreement - participant bank
Derivative [Line Items]
Instruments held | instrument	13	15
Maximum exposure	$ 1,500,000	$ 221,000
Notional amount	$ 149,000,000	$ 157,000,000
Risk participation agreement - lead bank
Derivative [Line Items]
Instruments held | instrument	9	10
Notional amount	$ 114,800,000	$ 86,300,000
Non-hedging | Commercial loan/lease
Derivative [Line Items]
Credit risk exposure, net of collateral pledged, relating to derivatives	$ 18,700,000	$ 16,700,000
Non-hedging | Interest rate cap | Commercial loan/lease
Derivative [Line Items]
Weighted average fixed interest rate	3.20%	2.40%
Interest-bearing deposits
Derivative [Line Items]
Cash collateral pledged for derivatives	$ 11,200,000	$ 14,000,000
Other assets
Derivative [Line Items]
Cash collateral pledged for derivatives	$ 14,100,000	$ 1,200,000

Stockholder's Equity (Details)

Stockholder's Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 02, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity Distribution Agreement [Line Items]
Net proceeds from issuance of stock				$ 236,467
Par value of preferred stock		$ 0.01	$ 0.01
Payments of dividends on preferred stock		$ 9,750	$ 9,750	9,750
Common Stock
Equity Distribution Agreement [Line Items]
Net proceeds from issuance of stock	$ 236,400			$ 35
Issuance of stock - shares	3,450,000			3,450,000
Repayments of short-term debt	$ 0

Quarterly Financial Data (Detai

Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Selected Quarterly Financial Information [Abstract]
Interest income	$ 321,718	$ 301,754	$ 286,852	$ 253,869	$ 249,519	$ 237,643	$ 208,191	$ 183,946	$ 1,164,193	$ 879,299	$ 703,408
Interest expense	81,045	69,579	55,140	43,569	38,870	33,282	25,232	20,587	249,333	117,971	63,594
Net interest income	240,673	232,175	231,712	210,300	210,649	204,361	182,959	163,359	914,860	761,328	639,814
Provision for credit losses	35,000	13,000	27,000	12,000	2,000	20,000	13,000	9,000	87,000	44,000	77,000
Net interest income after provision for credit losses	205,673	219,175	204,712	198,300	208,649	184,361	169,959	154,359	827,860	717,328	562,814
Non-interest income	15,280	25,518	17,279	19,947	19,374	19,003	18,769	17,110	78,024	74,256	60,780
Non-interest expense	129,862	136,143	132,131	126,960	133,138	114,830	111,814	106,094	525,096	465,876	382,397
Income before income taxes	91,091	108,550	89,860	91,287	94,885	88,534	76,914	65,375	380,788	325,708	241,197
Income tax expense	19,200	22,998	18,424	19,342	50,143	29,850	25,819	22,833	79,964	128,645	86,078
Net income	71,891	85,552	71,436	71,945	44,742	58,684	51,095	42,542	300,824	197,063	155,119
Preferred stock dividends	2,437	2,438	2,437	2,438	2,437	2,438	2,437	2,438	9,750	9,750	9,750
Net income available to common stockholders	$ 69,454	$ 83,114	$ 68,999	$ 69,507	$ 42,305	$ 56,246	$ 48,658	$ 40,104	$ 291,074	$ 187,313	$ 145,369
Basic earnings per share:
Basic earnings per common share	$ 1.38	$ 1.66	$ 1.39	$ 1.40	$ 0.85	$ 1.13	$ 0.98	$ 0.81	$ 5.83	$ 3.78	$ 3.14
Diluted earnings per share:
Diluted earnings per common share	$ 1.38	$ 1.65	$ 1.38	$ 1.38	$ 0.84	$ 1.12	$ 0.97	$ 0.80	$ 5.79	$ 3.73	$ 3.11
Average shares
Basic									49,936,702	49,587,169	46,239,210
Diluted									50,272,872	50,259,834	46,765,902

New Accounting Standards New Ac

New Accounting Standards New Accounting Standards (Details) - Subsequent Event - Accounting Standards Update 2016-02 $ in Millions	Jan. 01, 2019USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Lease, Right-of-Use Asset	$ 75
Lease liability	$ 75

Uncategorized Items - tcbi-2018

Label	Element	Value
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 2,000
AOCI Attributable to Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	84,000
Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (82,000)