Texas Capital Bancshares (TCBI) 10-Q 18 Apr 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	Apr. 18, 2019
Document And Entity Information [Abstract]
Entity Registrant Name	TEXAS CAPITAL BANCSHARES INC/TX
Entity Central Index Key	0001077428
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	Q1
Amendment Flag	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		50,273,887
Entity Current Reporting Status	Yes

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Assets
Cash and due from banks	$ 177,137	$ 214,191
Interest-bearing deposits in other banks	2,129,155	2,815,684
Federal funds sold and securities purchased under resale agreements	25,000	50,190
Investment securities	230,749	120,216
Loans held for sale ($1,901.6 million at March 31, 2019 and $1,969.2 million at December 31, 2018, at fair value)	1,901,637	1,969,474
Loans held for investment, mortgage finance	6,299,710	5,877,524
Loans held for investment (net of unearned income)	17,061,590	16,690,550
Less: Allowance for loan losses	(208,573)	(191,522)
Loans held for investment, net	23,152,727	22,376,552
Mortgage servicing rights, net	44,088	42,474
Premises and equipment, net	24,200	23,802
Accrued interest receivable and other assets	679,966	626,614
Goodwill and intangible assets, net	18,452	18,570
Total assets	28,383,111	28,257,767
Deposits:
Non-interest-bearing	6,743,607	7,317,161
Interest-bearing	13,906,520	13,288,952
Total deposits	20,650,127	20,606,113
Accrued interest payable	24,488	20,675
Other liabilities	233,398	194,238
Federal funds purchased and repurchase agreements	897,892	641,174
Other borrowings	3,600,000	3,900,000
Subordinated notes, net	281,858	281,767
Trust preferred subordinated debentures	113,406	113,406
Total liabilities	25,801,169	25,757,373
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	503	502
Additional paid-in capital	969,079	967,890
Retained earnings	1,461,893	1,381,492
Treasury stock (shares at cost: 417 at March 31, 2019 and December 31, 2018)	(8)	(8)
Accumulated other comprehensive income, net of taxes	475	518
Total stockholders’ equity	2,581,942	2,500,394
Total liabilities and stockholders’ equity	$ 28,383,111	$ 28,257,767

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Loans held for sale ($1,901.6 million at March 31, 2019 and $1,969.2 million at December 31, 2018, at fair value)	$ 1,901,600,000	$ 1,969,200,000
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, Liquidation value	$ 1,000	$ 1,000
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	50,264,028	50,201,127
Treasury stock, shares	417	417

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME AND OTHER COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Interest income
Interest and fees on loans	$ 312,703	$ 243,864
Investment securities	1,460	206
Federal funds sold and securities purchased under resale agreements	379	1,045
Interest-bearing deposits in other banks	11,019	8,754
Total interest income	325,561	253,869
Interest expense
Deposits	69,054	31,702
Federal funds purchased	3,516	969
Other borrowings	11,854	5,680
Subordinated notes	4,191	4,191
Trust preferred subordinated debentures	1,332	1,027
Total interest expense	89,947	43,569
Net interest income	235,614	210,300
Provision for credit losses	20,000	12,000
Net interest income after provision for credit losses	215,614	198,300
Non-interest income
Service charges on deposit accounts	2,979	3,137
Wealth management and trust fee income	2,009	1,924
Brokered loan fees	5,066	5,168
Servicing income	2,734	5,492
Swap fees	1,031	1,562
Net gain/(loss) on sale of loans held for sale	(505)	(2,173)
Other	16,700	4,837
Total non-interest income	30,014	19,947
Non-interest expense
Salaries and employee benefits	77,823	72,537
Net occupancy expense	7,879	7,234
Marketing	11,708	8,677
Legal and professional	10,030	7,530
Communications and technology	9,198	6,633
FDIC insurance assessment	5,122	6,103
Servicing related expenses	5,382	3,805
Allowance and other carrying costs for other real estate owned	0	2,155
Other	13,236	12,286
Total non-interest expense	140,378	126,960
Income before income taxes	105,250	91,287
Income tax expense	22,411	19,342
Net income	82,839	71,945
Preferred stock dividends	(2,438)	(2,438)
Net income available to common stockholders	80,401	69,507
Other comprehensive income (loss)
Change in unrealized gain (loss) on available-for-sale debt securities arising during period, before tax	(53)	(63)
Income tax expense (benefit) related to unrealized loss on available-for-sale debt securities	(10)	(13)
Other comprehensive income (loss), net of tax	(43)	(50)
Comprehensive income	$ 82,796	$ 71,895
Basic earnings per common share
Basic earnings per common share	$ 1.60	$ 1.40
Diluted earnings per common share
Diluted earnings per common share	$ 1.60	$ 1.38

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, 2017		(6,000,000)	(49,643,761)			(417)
Beginning balance - Amount at Dec. 31, 2017	$ 2,202,721	$ 150,000	$ 496	$ 961,305	$ 1,090,500	$ (8)	$ 428
Comprehensive income:
Net income	71,945				71,945
Change in unrealized gain (loss) on available-for-sale securities, net of taxes	(50)						(50)
Comprehensive income	71,895
Stock-based compensation expense recognized in earnings	1,957			1,957
Preferred stock dividends	(2,438)				(2,438)
Issuance of stock related to stock-based awards - Shares			26,430
Issuance of stock related to stock-based awards - Amount	(708)		$ 1	(709)
Ending balance - Amount at Mar. 31, 2018	2,273,429	$ 150,000	$ 497	962,553	1,159,925	$ (8)	462
Ending balance - Shares at Mar. 31, 2018		(6,000,000)	(49,670,191)			(417)
Beginning balance - Shares at Dec. 31, 2018		(6,000,000)	(50,201,127)			(417)
Beginning balance - Amount at Dec. 31, 2018	2,500,394	$ 150,000	$ 502	967,890	1,381,492	$ (8)	518
Comprehensive income:
Net income	82,839				82,839
Change in unrealized gain (loss) on available-for-sale securities, net of taxes	(43)						(43)
Comprehensive income	82,796
Stock-based compensation expense recognized in earnings	2,423			2,423
Preferred stock dividends	(2,438)				(2,438)
Issuance of stock related to stock-based awards - Shares			54,133
Issuance of stock related to stock-based awards - Amount	(1,233)		$ 1	(1,234)
Ending balance - Amount at Mar. 31, 2019	2,581,942	$ 150,000	$ 503	969,079	$ 1,461,893	$ (8)	$ 475
Ending balance - Shares at Mar. 31, 2019		(6,000,000)	(50,264,028)			(417)
Comprehensive income:
Stock Issued During Period, Shares, Other			8,768
Stock Issued During Period, Value, Other	$ 0		$ 0	$ 0

CONSOLIDATED STATEMENTS OF ST_2

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Stockholders' Equity [Abstract]
Income tax expense (benefit) related to unrealized loss on available-for-sale securities	$ 10	$ 13

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities
Net income	$ 82,839	$ 71,945
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	20,000	12,000
Depreciation and amortization	7,792	8,240
Net (gain)/loss on sale of loans held for sale	505	2,173
Increase (decrease) in valuation allowance on mortgage servicing rights	2,931	(757)
Stock-based compensation expense	4,488	5,971
Purchases and originations of loans held for sale	(1,550,059)	(1,479,006)
Proceeds from sales and repayments of loans held for sale	1,602,923	1,381,277
Other real estate owned write-down	0	2,000
Changes in operating assets and liabilities:
Accrued interest receivable and other assets	(58,278)	15,238
Accrued interest payable and other liabilities	51,023	(13,757)
Net cash provided by (used in) operating activities	164,164	5,324
Investing activities
Purchases of available-for-sale investment securities	(109,928)	(2,455)
Principal payments received on available-for-sale securities	307	763
Originations of mortgage finance loans	(24,328,971)	(19,821,894)
Proceeds from pay-offs of mortgage finance loans	23,906,785	20,440,116
Net increase in loans held for investment, excluding mortgage finance loans	(375,628)	(380,725)
Purchase of premises and equipment, net	(2,642)	(4,441)
Proceeds from sale of other real estate owned, net	79	184
Net cash provided by/(used in) by investing activities	(909,998)	231,548
Financing activities
Net increase/(decrease) in deposits	44,014	(358,647)
Costs from issuance of stock related to stock-based awards and warrants	(1,233)	(708)
Preferred dividends paid	(2,438)	(2,438)
Net increase/(decrease) in other borrowings	(300,000)	(500,000)
Net increase (decrease) in Federal funds purchased and repurchase agreements	256,718	170,500
Net cash provided by/(used in) financing activities	(2,939)	(691,293)
Net increase/(decrease) in cash and cash equivalents	(748,773)	(454,421)
Cash and cash equivalents at beginning of period	3,080,065	2,905,591
Cash and cash equivalents at end of period	2,331,292	2,451,170
Supplemental disclosures of cash flow information:
Cash paid during the period for interest	86,134	46,075
Cash paid during the period for income taxes	$ 6	$ 266

Operations and Summary of Signi

Operations and Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2019
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 lending 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. The consolidated interim financial statements are unaudited and certain information and footnote disclosures presented in accordance with GAAP have been condensed or omitted. In the opinion of management, the interim financial statements include all normal and recurring adjustments and the disclosures made are adequate to make the interim financial information not misleading. The consolidated financial statements have been prepared in accordance with GAAP for interim financial information and the instructions to Form 10-Q adopted by the Securities and Exchange Commission (“SEC”). Accordingly, the financial statements do not include all of the information and footnotes required by GAAP for complete financial statements and should be read in conjunction with our consolidated financial statements, and notes thereto, for the year ended December 31, 2018 , included in our Annual Report on Form 10-K filed with the SEC on February 14, 2019 (the “ 2018 Form 10-K”). Operating results for the interim periods disclosed herein are not necessarily indicative of the results that may be expected for a full year or any future period. Accounting Changes ASU 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 have not restated comparative periods. Of the optional practical expedients available under ASU 2016-02, all have been adopted except for the hindsight practical expedient. Our operating leases relate primarily to office space and bank branches. As a result of implementing ASU 2016-02, we recognized an operating lease right-of-use ("ROU") asset of $64 million and an operating lease liability of $74 million on January 1, 2019, with no impact on our consolidated statement of income or consolidated statement of cash flows compared to the prior lease accounting model. The ROU asset and operating lease liability are recorded in other assets and other liabilities, respectively, in the consolidated balance sheets. See Note 7 - Leases for additional information. 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.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The following table presents the computation of basic and diluted earnings per share: Three months ended March 31, (in thousands except per share data) 2019 2018 Numerator: Net income $ 82,839 $ 71,945 Preferred stock dividends 2,438 2,438 Net income available to common stockholders $ 80,401 $ 69,507 Denominator: Denominator for basic earnings per share—weighted average shares 50,229,797 49,650,884 Effect of employee stock-based awards(1) 115,602 255,794 Effect of warrants to purchase common stock — 446,819 Denominator for dilutive earnings per share—adjusted weighted average shares and assumed conversions 50,345,399 50,353,497 Basic earnings per common share $ 1.60 $ 1.40 Diluted earnings per common share $ 1.60 $ 1.38 (1) SARs and RSUs outstanding of 411,065 at March 31, 2019 and 5,139 at March 31, 2018 have not been included in diluted earnings per share because to do so would have been antidilutive for the periods presented.

Investment Securities

Investment Securities	3 Months Ended
	Mar. 31, 2019
Debt Securities, Available-for-sale [Abstract]
Investment Securities	Investment 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 March 31, 2019 Available-for-sale debt securities: Residential mortgage-backed securities $ 6,567 $ 361 $ — $ 6,928 Tax-exempt asset-backed securities 187,528 4,316 — 191,844 Credit risk transfer securities 14,713 — (4,076 ) 10,637 $ 208,808 $ 4,677 $ (4,076 ) $ 209,409 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 During the first quarter of 2019, we acquired a $92.0 million tax-exempt security backed with underlying cash flows from municipal revenue bonds, as well as $15.0 million in credit risk transfer ("CRT") securities. The securities were all recorded as available-for-sale upon acquisition and subsequently marked to fair value as of quarter end. CRT securities represent unsecured obligations issued by government sponsored entities ("GSEs") such as Freddie Mac and are designed to transfer mortgage credit risk from the GSE to private investors. CRT securities are structured to be subject to the performance of a reference pool of mortgage loans in which we share in 50% of the first losses with the GSE. If the reference pool incurs losses, the amount we will recover on the notes is reduced by our share of the amount of such losses, which could potentially be up to 100% of the amount outstanding. The CRT securities are generally interest-only for an initial period of time and are restricted from being transferred until a future date. 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 March 31, 2019 Available-for-sale: Residential mortgage-backed securities:(1) Amortized cost $ — $ 1,419 $ — $ 5,148 $ 6,567 Estimated fair value — 1,516 — 5,412 6,928 Weighted average yield(3) 6.50 % 5.54 % — % 4.59 % 4.79 % Tax-exempt asset-backed securities:(1) Amortized Cost — — — 187,528 187,528 Estimated fair value — — — 191,844 191,844 Weighted average yield(2)(3) — % — % — % 4.20 % 4.20 % CRT securities: Amortized Cost — — — 14,713 14,713 Estimated fair value — — — 10,637 10,637 Weighted average yield(3) — % — % — % 2.49 % 2.49 % Total available-for-sale debt securities: Amortized cost $ 208,808 Estimated fair value $ 209,409 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 (1) Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without prepayment penalties. (2) Yields have been adjusted to a tax equivalent basis assuming a 21% federal tax rate. (3) Yields are calculated based on amortized cost. The following table discloses as of March 31, 2019 our available-for-sale debt securities that have been in a continuous unrealized loss position for less than 12 months and those that have been in a continuous unrealized loss position for 12 or more months: March 31, 2019 Less Than 12 Months 12 Months or Longer Total (in thousands) Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss CRT securities $ 14,713 $ (4,076 ) $ — $ — $ 14,713 $ (4,076 ) At March 31, 2019 , the CRT securities were the only available-for-sale debt securities in an unrealized loss position. We conduct periodic reviews of securities with unrealized losses to evaluate whether the impairment is other-than-temporary. Unrealized losses that are determined to be temporary in nature are recorded, net of tax, in accumulated other comprehensive income ("AOCI") for available-for-sale debt securities. When we have the intent to sell or we believe we will more likely than not be required to sell an available-for-sale debt security, the entire excess of its amortized cost basis over its fair value is recognized in earnings. For available-for-sale debt securities that we do not intend to sell and are not likely to be required to sell, only the credit-related impairment is recognized in earnings and any non-credit-related impairment is recorded in AOCI. Based on the results of our periodic review of available-for-sale debt securities in an unrealized loss position at March 31, 2019, we recorded a $331,000 other-than-temporary credit-related impairment on the CRT securities, reducing the amortized cost of the securities. The loss was measured as the excess of the amortized costs basis of the security over the present value of cash flows expected to be collected and was recorded in other non-interest expense. These securities also have unrealized losses, which we do not believe are other-than-temporary. We have evaluated the near-term prospects of the investments in relation to the severity and duration of the impairment and based on that evaluation have determined that we have the ability and intent to hold the investments until recovery of fair value. Available-for-sale debt securities with carrying values of approximately $4.6 million and $1.6 million were pledged to secure certain customer repurchase agreements and deposits at March 31, 2019 . The comparative amounts at December 31, 2018 were $4.8 million and $1.7 million , respectively. Equity Securities Equity securities consist of Community Reinvestment Act funds and investments related to our non-qualified deferred compensation plan. At March 31, 2019 and December 31, 2018 , we had $21.3 million and $17.2 million , respectively, in equity securities recorded at fair value. The following is a summary of unrealized and realized gains/(losses) recognized on equity securities in other non-interest income in the consolidated statements of income: Three months ended March 31, (in thousands) 2019 2018 Net gains/(losses) recognized during the period $ 1,266 $ (212 ) Less: Realized net gains/(losses) recognized during the period on equity securities sold (30 ) — Unrealized net gains/(losses) recognized during the period on equity securities still held $ 1,296 $ (212 )

Loans Held for Investment and A

Loans Held for Investment and Allowance for Loan Losses	3 Months Ended
	Mar. 31, 2019
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: (in thousands) March 31, 2019 December 31, 2018 Commercial $ 10,673,960 $ 10,373,288 Mortgage finance(1) 6,299,710 5,877,524 Construction 2,493,192 2,120,966 Real estate 3,642,566 3,929,117 Consumer 61,377 63,438 Equipment leases 292,248 312,191 Gross loans held for investment 23,463,053 22,676,524 Deferred income (net of direct origination costs) (101,753 ) (108,450 ) Allowance for loan losses (208,573 ) (191,522 ) Total loans held for investment, net $ 23,152,727 $ 22,376,552 (1) Balances at March 31, 2019 and December 31, 2018 are stated net of $185.4 million and $193.0 million of participations sold, respectively. 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 March 31, 2019 Grade: Pass $ 10,205,865 $ 6,299,710 $ 2,478,880 $ 3,526,380 $ 59,759 $ 289,664 $ 22,860,258 Special mention 200,920 — — 75,755 — 1,975 278,650 Substandard-accruing 145,988 — 14,312 27,980 1,566 609 190,455 Non-accrual 121,187 — — 12,451 52 — 133,690 Total loans held for investment $ 10,673,960 $ 6,299,710 $ 2,493,192 $ 3,642,566 $ 61,377 $ 292,248 $ 23,463,053 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 The allowance for loan losses is comprised of general reserves and specific reserves for impaired loans based on our estimate of losses inherent in the portfolio at the balance sheet date, but not yet identified with specified loans. We believe the allowance at March 31, 2019 to be appropriate, given management's assessment of losses inherent in the portfolio as of the evaluation date, the 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 Three months ended March 31, 2019 Allowance for loan losses: Beginning balance $ 129,442 $ — $ 19,242 $ 33,353 $ 425 $ 1,829 $ 7,231 $ 191,522 Provision for loan losses 25,506 1,300 3,583 (1,272 ) (46 ) (201 ) (7,231 ) 21,639 Charge-offs 4,865 — — — — — — 4,865 Recoveries 266 — — — 10 1 — 277 Net charge-offs (recoveries) 4,599 — — — (10 ) (1 ) — 4,588 Ending balance $ 150,349 $ 1,300 $ 22,825 $ 32,081 $ 389 $ 1,629 $ — $ 208,573 Period end allowance for loan losses allocated to: Loans individually evaluated for impairment $ 27,409 $ — $ — $ 1,599 $ 10 $ — $ — $ 29,018 Loans collectively evaluated for impairment 122,940 1,300 22,825 30,482 379 1,629 — 179,555 Total $ 150,349 $ 1,300 $ 22,825 $ 32,081 $ 389 $ 1,629 $ — $ 208,573 Period end loans allocated to: Loans individually evaluated for impairment $ 121,187 $ — $ — $ 18,709 $ 52 $ — $ — $ 139,948 Loans collectively evaluated for impairment 10,552,773 6,299,710 2,493,192 3,623,857 61,325 292,248 — 23,323,105 Total $ 10,673,960 $ 6,299,710 $ 2,493,192 $ 3,642,566 $ 61,377 $ 292,248 $ — $ 23,463,053 Three months ended March 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 17,546 — (518 ) (200 ) (178 ) (18 ) (5,184 ) 11,448 Charge-offs 5,667 — — — — — — 5,667 Recoveries 360 — — 24 59 19 — 462 Net charge-offs (recoveries) 5,307 — — (24 ) (59 ) (19 ) — 5,205 Ending balance $ 131,045 $ — $ 18,755 $ 34,111 $ 238 $ 3,543 $ 3,206 $ 190,898 Period end allowance for loan losses allocated to: Loans individually evaluated for impairment $ 34,897 $ — $ — $ 22 $ 2 $ — $ — $ 34,921 Loans collectively evaluated for impairment 96,148 — 18,755 34,089 236 3,543 3,206 155,977 Total $ 131,045 $ — $ 18,755 $ 34,111 $ 238 $ 3,543 $ 3,206 $ 190,898 Period end loans allocated to: Loans individually evaluated for impairment $ 123,206 $ — $ — $ 1,187 $ 72 $ — $ — $ 124,465 Loans collectively evaluated for impairment 9,337,818 4,689,938 2,224,403 3,833,571 47,239 276,303 — 20,409,272 Total $ 9,461,024 $ 4,689,938 $ 2,224,403 $ 3,834,758 $ 47,311 $ 276,303 $ — $ 20,533,737 During the first quarter of 2019, we refined our methodology for calculating the allowance for loan losses to improve the specificity of the risk weights and the risk-weighting process for each product type assigned to the loans in our held for investment portfolio. As a result of these refinements, management is better able to allocate inherent losses previously accounted for in the additional qualitative reserve component of our allowance for loan losses to specific product types and credit risk grades, thus eliminating the additional qualitative reserve component of our allowance for loan losses in the first quarter of 2019. Additionally, this improved specificity and consideration of current mortgage market conditions has resulted in the allocation of a portion of the company’s provision for loan losses to our mortgage finance loan portfolio for the first time in the first quarter of 2019. 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 March 31, 2019 With no related allowance recorded: Commercial Business loans $ 21,075 $ 37,077 $ — $ 12,218 $ — Energy loans 9,048 10,124 — 5,724 — Real estate Market risk — — — — — Commercial 7,220 7,220 — 4,048 — Secured by 1-4 family 1,228 1,228 — 683 — Consumer — — — — — Equipment leases — — — — — Total impaired loans with no allowance recorded $ 38,571 $ 55,649 $ — $ 22,673 $ — With an allowance recorded: Commercial Business loans $ 23,374 $ 23,909 $ 9,663 $ 11,687 $ — Energy loans 67,690 70,551 17,746 28,195 — Real estate Market risk 8,478 8,478 1,378 2,826 — Commercial — — — — — Secured by 1-4 family 1,783 1,783 221 647 — Consumer 52 52 10 30 — Equipment leases — — — — — Total impaired loans with an allowance recorded $ 101,377 $ 104,773 $ 29,018 $ 43,385 $ — Combined: Commercial Business loans $ 44,449 $ 60,986 $ 9,663 $ 23,905 $ — Energy loans 76,738 80,675 17,746 33,919 — Real estate Market risk 8,478 8,478 1,378 2,826 — Commercial 7,220 7,220 — 4,048 — Secured by 1-4 family 3,011 3,011 221 1,330 — Consumer 52 52 10 30 — Equipment leases — — — — — Total impaired loans $ 139,948 $ 160,422 $ 29,018 $ 66,058 $ — (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 — 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 — 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 — 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 Average impaired loans outstanding during the three months ended March 31, 2019 , and 2018 totaled $66.1 million and $109.9 million , respectively. As of March 31, 2019 and December 31, 2018, 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 March 31, 2019 Commercial Business loans $ 32,935 $ 13,524 $ 12,093 $ 58,552 $ 44,449 $ 8,869,686 $ 8,972,687 Energy 603 — — 603 76,738 1,623,932 1,701,273 Mortgage finance loans — — — — — 6,299,710 6,299,710 Construction Market risk 688 14,312 — 15,000 — 2,367,746 2,382,746 Commercial — — — — — 80,659 80,659 Secured by 1-4 family — — — — — 29,787 29,787 Real estate Market risk 5,030 607 — 5,637 8,478 2,546,670 2,560,785 Commercial 4,834 669 — 5,503 962 719,349 725,814 Secured by 1-4 family 7,748 — 86 7,834 3,011 345,122 355,967 Consumer 2,442 75 66 2,583 52 58,742 61,377 Equipment leases 1,697 — — 1,697 — 290,551 292,248 Total loans held for investment $ 55,977 $ 29,187 $ 12,245 $ 97,409 $ 133,690 $ 23,231,954 $ 23,463,053 (1) Loans past due 90 days and still accruing includes premium finance loans of $12.0 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 March 31, 2019 and December 31, 2018 , we did not have any loans considered restructured that were not on non-accrual. Of the non-accrual loans at March 31, 2019 and December 31, 2018 , $38.4 million and $20.0 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 March 31, 2019 of loans that have been restructured during the three months ended March 31, 2019 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 Three months ended March 31, 2019 Commercial: Energy loans 1 $ 22,540 — $ — 1 $ 22,540 We did not have any loans that were restructured during the three months ended March 31, 2018. 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 March 31, 2019 , all of the above loans restructured in 2019 are on non-accrual. The restructuring of the loans did not have a significant impact on our allowance for loan losses at March 31, 2019 or 2018 . As of March 31, 2019 and 2018 , 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	3 Months Ended
	Mar. 31, 2019
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: Three months ended March 31, (in thousands) 2019 2018 Beginning balance $ 79 $ 11,742 Sales (79 ) (184 ) Valuation allowance for OREO — (2,000 ) Ending balance $ — $ 9,558

Certain Transfers of Financial

Certain Transfers of Financial Assets	3 Months Ended
	Mar. 31, 2019
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: Three Months Ended March 31, Three Months Ended March 31, (in thousands) 2019 2018 Outstanding balance: Beginning balance(1) $ 1,949,785 $ 1,012,580 Loans purchased 1,550,059 1,479,006 Payments and loans sold (1,617,518 ) (1,399,683 ) Ending balance 1,882,326 1,091,903 Fair value adjustment: Beginning balance(1) 19,689 (1,576 ) Increase/(decrease) to fair value (378 ) (1,762 ) Ending balance 19,311 (3,338 ) Loans held for sale at fair value $ 1,901,637 $ 1,088,565 (1) Includes $299,000 of loans held for sale that are carried at lower of cost or market as of December 31, 2018 . No loans held for sale were on non-accrual as of March 31, 2019 or December 31, 2018 . At March 31, 2019 and December 31, 2018 , we had $13.7 million and $16.8 million , respectively, in loans held for sale that were 90 days or more past due. The $13.7 million in loans held for sale that were 90 days or more past due at March 31, 2019 included $12.5 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. Also included in the $13.7 million were $317,000 in loans that, pursuant to Ginnie Mae servicing guidelines, we have the unilateral right, but not the obligation, to repurchase if defined delinquent loan criteria are met, and therefore must record as held for sale on our balance sheet regardless of whether the repurchase option has been exercised. At December 31, 2018 $16.0 million of the $16.8 million in loans held for sale were 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. 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: Three months ended March 31, (in thousands) 2019 2018 MSRs: Balance, beginning of year $ 42,474 $ 88,150 Capitalized servicing rights 6,138 16,750 Amortization (1,593 ) (2,741 ) Sales — (25,598 ) Balance, end of period $ 47,019 $ 76,561 Valuation allowance: Balance, beginning of year $ — $ 2,823 Increase (decrease) in valuation allowance 2,931 (2,823 ) Balance, end of period $ 2,931 $ — MSRs, net $ 44,088 $ 76,561 MSRs, fair value $ 44,691 $ 82,274 At March 31, 2019 and December 31, 2018 , our servicing portfolio of residential mortgage loans had an outstanding principal balance of $4.4 billion and $3.9 billion , respectively. 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 $49.6 million at March 31, 2019 and $37.9 million at December 31, 2018 . 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 March 31, 2019 , the estimated fair value of MSRs was adjusted as a result of the decline in mortgage interest rates experienced in the first quarter of 2019, which resulted in a $2.9 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: March 31, 2019 December 31, 2018 Average discount rates 9.54 % 9.55 % Expected prepayment speeds 12.07 % 9.77 % Weighted-average life, in years 6.1 7.0 A sensitivity analysis of changes in the fair value of our MSR portfolio resulting from certain key assumptions is presented in the following table: (in thousands) March 31, 2019 December 31, 2018 50 bp adverse change in prepayment speed $ (6,407 ) $ (6,028 ) 100 bp adverse change in prepayment speed (10,989 ) (11,629 ) 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 at both March 31, 2018 and December 31, 2018 , respectively, and is recorded in other liabilities in the consolidated balance sheets. We incurred $ 162,000 in losses due to repurchase, indemnification and make-whole obligations during the three months ended March 31, 2019 compared to $56,000 during the three months ended March 31, 2018 .

Leases

Leases	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Leases	Leases Operating leases in which we are the lessee are recorded as operating lease ROU assets and operating lease liabilities, included in other assets and other liabilities, respectively, on our consolidated balance sheets. We do not currently have any significant finance leases in which we are the lessee. Operating lease ROU assets represent our right to use an underlying asset during the lease term and operating lease liabilities represent our obligation to make lease payments arising from the lease. ROU assets and operating lease liabilities are recognized at lease commencement based on the present value of the remaining lease payments using a discount rate that represents our incremental borrowing rate at the lease commencement date. ROU assets are further adjusted for lease incentives. Operating lease expense, which is comprised of amortization of the ROU asset and the implicit interest accreted on the operating lease liability, is recognized on a straight-line basis over the lease term, and is recorded in net occupancy expense in the consolidated statements of income and other comprehensive income. Our leases relate primarily to office space and bank branches with remaining lease terms of generally 1 to 11 years . Certain lease arrangements contain extension options which typically range from 5 to 10 years at the then fair market rental rates. As these extension options are not generally considered reasonably certain of exercise, they are not included in the lease term. As of March 31, 2019, operating lease ROU assets and liabilities were $62.2 million and $71.7 million , respectively. The table below summarizes our net lease cost: (in thousands) Three months ended Operating lease cost $ 3,516 Variable lease cost 903 Sublease income (31 ) Net lease cost $ 4,388 The table below summarizes other information related to our operating leases: (in thousands except for percent and period data) Three months ended Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 3,781 Right-of-use assets obtained in exchange for new finance lease liabilities 64,493 Weighted-average remaining lease term - operating leases, in years 5.9 Weighted-average discount rate - operating leases 2.8 % The table below summarizes the maturity of remaining lease liabilities: (in thousands) March 31, 2019 2019 $ 10,878 2020 14,521 2021 14,236 2022 13,372 2023 12,400 2024 and thereafter 12,327 Total lease payments 77,734 Less: Interest (6,048 ) Present value of lease liabilities $ 71,686 As of March 31, 2019, we have $18.4 million in additional operating leases for office space that have not yet commenced that are anticipated to commence during the second quarter of 2019.

Financial Instruments with Off-

Financial Instruments with Off-Balance Sheet Risk	3 Months Ended
	Mar. 31, 2019
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. Three months ended March 31, (in thousands) 2019 2018 Beginning balance of allowance for off-balance sheet credit losses $ 11,434 $ 9,071 Provision for off-balance sheet credit losses (1,639 ) 552 Ending balance of allowance for off-balance sheet credit losses $ 9,795 $ 9,623 (in thousands) March 31, 2019 December 31, 2018 Commitments to extend credit - period end balance $ 7,846,910 $ 8,030,198 Standby letters of credit - period end balance $ 265,125 $ 236,537

Regulatory Restrictions

Regulatory Restrictions	3 Months Ended
	Mar. 31, 2019
Regulatory Capital Requirements [Abstract]
Regulatory Restrictions	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 that fully phased in beginning 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 was fully phased-in on January 1, 2019 at 2.5% . The required phase-in capital conservation buffer during 2018 was 1.875% . 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 March 31, 2019 , 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 March 31, 2019 and December 31, 2018 . 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 adverse effect on our financial condition and results of operations. Because our Bank had less than $15.0 billion in total consolidated assets as of December 31, 2009, we are allowed to continue to classify our trust preferred securities, all of which were issued prior to May 19, 2010, as Tier 1 capital. The table below summarizes our actual and required capital ratios under the Basel III Capital Rules: Actual Minimum Capital Required - Basel III Phase-In Schedule Minimum capital Required - Basel III Fully Phased-In Required to be Considered Well Capitalized (dollars in thousands) Capital Amount Ratio Capital Amount Ratio Capital Amount Ratio Capital Amount Ratio March 31, 2019 CET1 Company $ 2,412,290 8.64 % N/A N/A $ 1,954,119 7.00 % N/A N/A Bank 2,426,687 8.70 % N/A N/A 1,953,530 7.00 % 1,813,992 6.50 % Total capital (to risk-weighted assets) Company 3,169,288 11.35 % N/A N/A 2,931,179 10.50 % N/A N/A Bank 3,025,046 10.84 % N/A N/A 2,930,295 10.50 % 2,790,757 10.00 % Tier 1 capital (to risk-weighted assets) Company 2,669,063 9.56 % N/A N/A 2,372,859 8.50 % N/A N/A Bank 2,583,460 9.26 % N/A N/A 2,372,143 8.50 % 2,232,605 8.00 % Tier 1 capital (to average assets)(1) Company 2,669,063 10.02 % N/A N/A 1,065,414 4.00 % N/A N/A Bank 2,583,460 9.70 % N/A N/A 1,064,951 4.00 % 1,331,188 5.00 % 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 % (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 March 31, 2019 , our total mortgage finance loans were $6.3 billion compared to the average for the quarter ended March 31, 2019 of $4.9 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 the three months ended March 31, 2019 , or 2018 .

Stock-based Compensation

Stock-based Compensation	3 Months Ended
	Mar. 31, 2019
Compensation Related Costs [Abstract]
Stock-based Compensation	Stock-based Compensation We have long-term incentive plans under which stock-based compensation awards are granted to employees and directors by the board of directors, or its designated committee. Grants are subject to vesting requirements and may include, among other things, nonqualified stock options, stock appreciation rights ("SARs"), restricted stock units ("RSUs"), restricted stock and performance units, or any combination thereof. There are 2,550,000 total shares authorized for grant under the plans. The table below summarizes our stock-based compensation expense for the three months ended March 31, 2019 and 2018 : Three months ended March 31, (in thousands) 2019 2018 Stock-settled awards: SARs $ 6 $ 50 RSUs 2,407 1,896 Restricted stock 10 11 Cash-settled performance units 2,065 4,014 Total $ 4,488 $ 5,971 (in thousands except period data) March 31, 2019 Unrecognized compensation expense related to unvested stock-settled awards $ 30,167 Weighted average period over which expense is expected to be recognized, in years 3.3

Fair Value Disclosures

Fair Value Disclosures	3 Months Ended
	Mar. 31, 2019
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 March 31, 2019 Available-for-sale debt securities:(1) Residential mortgage-backed securities $ — $ 6,928 $ — Tax-exempt asset-backed securities — — 191,844 CRT securities — — 10,637 Equity securities(1)(2) 14,338 7,002 — Loans held for sale(3) — 1,888,591 13,046 Loans held for investment(4)(6) — — 39,719 Derivative assets(7) — 31,049 — Derivative liabilities(7) — 42,288 — Non-qualified deferred compensation plan liabilities(8) 14,548 — — 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 — — (1) Securities are measured at fair value on a recurring basis, generally monthly, except for tax-exempt asset-backed securities and CRT 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 corresponds 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: Net Realized/Unrealized Gains (Losses) (in thousands) Balance at Beginning of Period Purchases / Additions Sales / Reductions Realized Unrealized Balance at End of Period Three months ended March 31, 2019 Available-for-sale debt securities:(1) Tax-exempt asset-backed securities $ 95,804 $ 92,010 $ — $ — $ 4,030 $ 191,844 CRT securities $ — $ 15,044 $ — $ (331 ) $ (4,076 ) $ 10,637 Loans held for sale(2) $ 16,415 $ — $ (3,878 ) $ 216 $ 293 $ 13,046 Three months ended March 31, 2018 Loans held for sale(2) $ — $ 36,092 $ — $ — $ (1,841 ) $ 34,251 (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 March 31, 2019 , a discount rate of 3.89% and a weighted-average life of 8.4 years were utilized to determine the fair value of these securities, compared to 4.21% and 9.2 years, respectively, at December 31, 2018 . CRT securities The fair value of CRT 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 March 31, 2019 , a discount rate of 6.92% and a weighted-average life of 8.6 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 March 31, 2019 , the fair value of these loans was calculated using a weighted-average discounted price of 93.2% compared to 92.9% at December 31, 2018 . 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 $39.7 million fair value of loans held for investment at March 31, 2019 reported above includes impaired loans held for investment with a carrying value of $53.0 million that were reduced by specific valuation allowance allocations totaling $13.3 million based on collateral valuations utilizing Level 3 inputs. The $29.9 million fair value of loans held for investment at December 31, 2018 reported above includes impaired loans 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. 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 , OREO had a carrying value of $79,000 , with no specific valuation allowance. The fair value of OREO was computed based on third party appraisals, which are Level 3 inputs. Fair Value of Financial Instruments GAAP requires disclosure of fair value information about financial instruments, whether or not recognized on the balance sheet, for which it is practical to estimate that value. In cases where quoted market prices are not available, fair values are based on estimates using present value or other valuation techniques. Those techniques are significantly affected by the assumptions used, including the discount rate and estimates of future cash flows. This disclosure does not and is not intended to represent the fair value of the Company. A summary of the carrying amounts and estimated fair values of financial instruments is as follows: March 31, 2019 December 31, 2018 (in thousands) Carrying Amount Estimated Fair Value Carrying Estimated Financial assets: Level 1 inputs: Cash and cash equivalents $ 2,331,292 $ 2,331,292 $ 3,080,065 $ 3,080,065 Investment securities 14,338 14,338 10,262 10,262 Level 2 inputs: Investment securities 13,930 13,930 14,150 14,150 Loans held for sale 1,888,591 1,888,591 1,953,059 1,953,059 Derivative assets 31,049 31,049 21,806 21,806 Level 3 inputs: Investment securities 202,481 202,481 95,804 95,804 Loans held for sale 13,046 13,046 16,415 16,415 Loans held for investment, net 23,152,727 23,152,057 22,376,552 22,347,876 Financial liabilities: Level 2 inputs: Federal funds purchased 886,426 886,426 629,169 629,169 Customer repurchase agreements 11,466 11,466 12,005 12,005 Other borrowings 3,600,000 3,600,000 3,900,000 3,900,000 Subordinated notes 281,858 289,179 281,767 283,349 Trust preferred subordinated debentures 113,406 113,406 113,406 113,406 Derivative liabilities 42,288 42,288 41,375 41,375 Level 3 inputs: Deposits 20,650,127 20,651,839 20,606,113 20,608,494 The estimated fair value for cash and cash equivalents, variable rate loans and variable rate debt approximates carrying value. 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 and CRT 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.

Derivative Financial Instrument

Derivative Financial Instruments	3 Months Ended
	Mar. 31, 2019
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: March 31, 2019 December 31, 2018 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 $ 1,590,394 $ 3,626 $ 27,508 $ 1,579,328 $ 7,978 $ 16,719 Commercial loan/lease interest rate caps 649,549 383 2 606,950 1,109 4 Foreign currency forward contracts 21,580 1,847 14 39,737 2,263 59 Customer counterparties: Commercial loan/lease interest rate swaps 1,590,394 27,508 3,626 1,579,328 16,719 7,978 Commercial loan/lease interest rate caps 649,549 2 383 606,950 4 1,109 Foreign currency forward contracts 21,580 14 1,847 39,737 59 2,263 Economic hedging interest rate derivatives: Loan purchase commitments 239,573 1,297 77 167,984 1,442 6 Forward sale commitments 1,623,500 — 12,459 1,928,527 — 21,005 Gross derivatives 34,677 45,916 29,574 49,143 Offsetting derivative assets/liabilities (3,628 ) (3,628 ) (7,768 ) (7,768 ) Net derivatives included in the consolidated balance sheets $ 31,049 $ 42,288 $ 21,806 $ 41,375 The weighted-average received and paid interest rates for interest rate swaps outstanding were as follows: March 31, 2019 Weighted-Average Interest Rate December 31, 2018 Weighted-Average Interest Rate Received Paid Received Paid Non-hedging interest rate swaps 4.14 % 4.09 % 4.24 % 4.20 % The weighted-average strike rate for outstanding interest rate caps was 3.22% at March 31, 2019 and 3.20% at December 31, 2018 . 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 $30.0 million at March 31, 2019 and approximately $18.7 million at December 31, 2018 . 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 March 31, 2019 , we had $43.5 million in cash collateral pledged for these derivatives, of which $31.7 million was included in interest-bearing deposits in other banks and $11.8 million was included in accrued interest receivable and other assets. 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 and $14.1 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 12 risk participation agreements where we are a participant bank with a notional amount of $144.7 million at March 31, 2019 , compared to 13 risk participation agreements having a notional amount of $149.1 million at December 31, 2018 . The maximum estimated exposure to these agreements, assuming 100% default by all obligors, was approximately $2.2 million at March 31, 2019 and $1.5 million at December 31, 2018 . The fair value of these exposures was insignificant to the consolidated financial statements at both March 31, 2019 and December 31, 2018 . Risk participation agreements entered into by us as the lead bank provide credit protection to us should the borrower fail to perform on its interest rate derivative contract with us. We are party to 10 risk participation agreements where we are the lead bank having a notional amount of $124.3 million at March 31, 2019 , compared to 9 agreements having a notional amount of $114.8 million at December 31, 2018 .

New Accounting Standards

New Accounting Standards	3 Months Ended
	Mar. 31, 2019
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
New Accounting Standards	New Accounting Standards ASU 2019-01 "Leases (Topic 842)" ("ASU 2019-1") provides clarifications to increase transparency and comparability among organizations by recognizing lease assets and liabilities on the balance sheet and disclosing essential information about leasing transactions. Specifically, ASU 2019-01 (i) allows the fair value of the underlying asset reported by lessors that are not manufacturers or dealers to continue to be its cost and not fair value as measured under the fair value definition, (ii) allows for the cash flows received for sales-type and direct financing leases to continue to be presented as results from investing, and (iii) clarifies that entities do not have to disclose the effect of the lease standard on adoption year interim amounts. ASU 2019-01 will be effective for us on January 1, 2020 and will not have any material impact on our consolidated financial statements. 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 implement this new accounting standard. Implementation activities have focused on data capture and portfolio segmentation with continued progress toward model validation and testing.

Operations and Summary of Sig_2

Operations and Summary of Significant Accounting Policies Operations and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2019
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. Our national lines of business provide specialized lending products to businesses throughout the United States.
Basis of Accounting	Basis of Presentation Our accounting and reporting policies conform to accounting principles generally accepted in the United States ("GAAP") and to generally accepted practices within the banking industry. Certain prior period balances have been reclassified to conform to the current period presentation. The consolidated interim financial statements are unaudited and certain information and footnote disclosures presented in accordance with GAAP have been condensed or omitted. In the opinion of management, the interim financial statements include all normal and recurring adjustments and the disclosures made are adequate to make the interim financial information not misleading. The consolidated financial statements have been prepared in accordance with GAAP for interim financial information and the instructions to Form 10-Q adopted by the Securities and Exchange Commission (“SEC”). Accordingly, the financial statements do not include all of the information and footnotes required by GAAP for complete financial statements and should be read in conjunction with our consolidated financial statements, and notes thereto, for the year ended December 31, 2018 , included in our Annual Report on Form 10-K filed with the SEC on February 14, 2019 (the “ 2018 Form 10-K”). Operating results for the interim periods disclosed herein are not necessarily indicative of the results that may be expected for a full year or any future period.
New Accounting Pronouncements	Accounting Changes 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 have not restated comparative periods. Of the optional practical expedients available under ASU 2016-02, all have been adopted except for the hindsight practical expedient. Our operating leases relate primarily to office space and bank branches. As a result of implementing ASU 2016-02, we recognized an operating lease right-of-use ("ROU") asset of $64 million and an operating lease liability of $74 million on January 1, 2019, with no impact on our consolidated statement of income or consolidated statement of cash flows compared to the prior lease accounting model. The ROU asset and operating lease liability are recorded in other assets and other liabilities, respectively, in the consolidated balance sheets. See Note 7 - Leases for additional information.
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.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2019
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: Three months ended March 31, (in thousands except per share data) 2019 2018 Numerator: Net income $ 82,839 $ 71,945 Preferred stock dividends 2,438 2,438 Net income available to common stockholders $ 80,401 $ 69,507 Denominator: Denominator for basic earnings per share—weighted average shares 50,229,797 49,650,884 Effect of employee stock-based awards(1) 115,602 255,794 Effect of warrants to purchase common stock — 446,819 Denominator for dilutive earnings per share—adjusted weighted average shares and assumed conversions 50,345,399 50,353,497 Basic earnings per common share $ 1.60 $ 1.40 Diluted earnings per common share $ 1.60 $ 1.38 (1) SARs and RSUs outstanding of 411,065 at March 31, 2019 and 5,139 at March 31, 2018 have not been included in diluted earnings per share because to do so would have been antidilutive for the periods presented.

Investment Securities (Tables)

Investment Securities (Tables)	3 Months Ended
	Mar. 31, 2019
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 March 31, 2019 Available-for-sale debt securities: Residential mortgage-backed securities $ 6,567 $ 361 $ — $ 6,928 Tax-exempt asset-backed securities 187,528 4,316 — 191,844 Credit risk transfer securities 14,713 — (4,076 ) 10,637 $ 208,808 $ 4,677 $ (4,076 ) $ 209,409 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
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 March 31, 2019 Available-for-sale: Residential mortgage-backed securities:(1) Amortized cost $ — $ 1,419 $ — $ 5,148 $ 6,567 Estimated fair value — 1,516 — 5,412 6,928 Weighted average yield(3) 6.50 % 5.54 % — % 4.59 % 4.79 % Tax-exempt asset-backed securities:(1) Amortized Cost — — — 187,528 187,528 Estimated fair value — — — 191,844 191,844 Weighted average yield(2)(3) — % — % — % 4.20 % 4.20 % CRT securities: Amortized Cost — — — 14,713 14,713 Estimated fair value — — — 10,637 10,637 Weighted average yield(3) — % — % — % 2.49 % 2.49 % Total available-for-sale debt securities: Amortized cost $ 208,808 Estimated fair value $ 209,409 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 (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 on equity securities in other non-interest income in the consolidated statements of income: Three months ended March 31, (in thousands) 2019 2018 Net gains/(losses) recognized during the period $ 1,266 $ (212 ) Less: Realized net gains/(losses) recognized during the period on equity securities sold (30 ) — Unrealized net gains/(losses) recognized during the period on equity securities still held $ 1,296 $ (212 )

Loans Held for Investment and_2

Loans Held for Investment and Allowance for Loan Losses (Tables)	3 Months Ended
	Mar. 31, 2019
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: (in thousands) March 31, 2019 December 31, 2018 Commercial $ 10,673,960 $ 10,373,288 Mortgage finance(1) 6,299,710 5,877,524 Construction 2,493,192 2,120,966 Real estate 3,642,566 3,929,117 Consumer 61,377 63,438 Equipment leases 292,248 312,191 Gross loans held for investment 23,463,053 22,676,524 Deferred income (net of direct origination costs) (101,753 ) (108,450 ) Allowance for loan losses (208,573 ) (191,522 ) Total loans held for investment, net $ 23,152,727 $ 22,376,552 (1) Balances at March 31, 2019 and December 31, 2018 are stated net of $185.4 million and $193.0 million of participations sold, respectively.
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 March 31, 2019 Grade: Pass $ 10,205,865 $ 6,299,710 $ 2,478,880 $ 3,526,380 $ 59,759 $ 289,664 $ 22,860,258 Special mention 200,920 — — 75,755 — 1,975 278,650 Substandard-accruing 145,988 — 14,312 27,980 1,566 609 190,455 Non-accrual 121,187 — — 12,451 52 — 133,690 Total loans held for investment $ 10,673,960 $ 6,299,710 $ 2,493,192 $ 3,642,566 $ 61,377 $ 292,248 $ 23,463,053 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
Schedule of activity in the reserve for loan losses by portfolio segment	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 Three months ended March 31, 2019 Allowance for loan losses: Beginning balance $ 129,442 $ — $ 19,242 $ 33,353 $ 425 $ 1,829 $ 7,231 $ 191,522 Provision for loan losses 25,506 1,300 3,583 (1,272 ) (46 ) (201 ) (7,231 ) 21,639 Charge-offs 4,865 — — — — — — 4,865 Recoveries 266 — — — 10 1 — 277 Net charge-offs (recoveries) 4,599 — — — (10 ) (1 ) — 4,588 Ending balance $ 150,349 $ 1,300 $ 22,825 $ 32,081 $ 389 $ 1,629 $ — $ 208,573 Period end allowance for loan losses allocated to: Loans individually evaluated for impairment $ 27,409 $ — $ — $ 1,599 $ 10 $ — $ — $ 29,018 Loans collectively evaluated for impairment 122,940 1,300 22,825 30,482 379 1,629 — 179,555 Total $ 150,349 $ 1,300 $ 22,825 $ 32,081 $ 389 $ 1,629 $ — $ 208,573 Period end loans allocated to: Loans individually evaluated for impairment $ 121,187 $ — $ — $ 18,709 $ 52 $ — $ — $ 139,948 Loans collectively evaluated for impairment 10,552,773 6,299,710 2,493,192 3,623,857 61,325 292,248 — 23,323,105 Total $ 10,673,960 $ 6,299,710 $ 2,493,192 $ 3,642,566 $ 61,377 $ 292,248 $ — $ 23,463,053 Three months ended March 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 17,546 — (518 ) (200 ) (178 ) (18 ) (5,184 ) 11,448 Charge-offs 5,667 — — — — — — 5,667 Recoveries 360 — — 24 59 19 — 462 Net charge-offs (recoveries) 5,307 — — (24 ) (59 ) (19 ) — 5,205 Ending balance $ 131,045 $ — $ 18,755 $ 34,111 $ 238 $ 3,543 $ 3,206 $ 190,898 Period end allowance for loan losses allocated to: Loans individually evaluated for impairment $ 34,897 $ — $ — $ 22 $ 2 $ — $ — $ 34,921 Loans collectively evaluated for impairment 96,148 — 18,755 34,089 236 3,543 3,206 155,977 Total $ 131,045 $ — $ 18,755 $ 34,111 $ 238 $ 3,543 $ 3,206 $ 190,898 Period end loans allocated to: Loans individually evaluated for impairment $ 123,206 $ — $ — $ 1,187 $ 72 $ — $ — $ 124,465 Loans collectively evaluated for impairment 9,337,818 4,689,938 2,224,403 3,833,571 47,239 276,303 — 20,409,272 Total $ 9,461,024 $ 4,689,938 $ 2,224,403 $ 3,834,758 $ 47,311 $ 276,303 $ — $ 20,533,737
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 March 31, 2019 With no related allowance recorded: Commercial Business loans $ 21,075 $ 37,077 $ — $ 12,218 $ — Energy loans 9,048 10,124 — 5,724 — Real estate Market risk — — — — — Commercial 7,220 7,220 — 4,048 — Secured by 1-4 family 1,228 1,228 — 683 — Consumer — — — — — Equipment leases — — — — — Total impaired loans with no allowance recorded $ 38,571 $ 55,649 $ — $ 22,673 $ — With an allowance recorded: Commercial Business loans $ 23,374 $ 23,909 $ 9,663 $ 11,687 $ — Energy loans 67,690 70,551 17,746 28,195 — Real estate Market risk 8,478 8,478 1,378 2,826 — Commercial — — — — — Secured by 1-4 family 1,783 1,783 221 647 — Consumer 52 52 10 30 — Equipment leases — — — — — Total impaired loans with an allowance recorded $ 101,377 $ 104,773 $ 29,018 $ 43,385 $ — Combined: Commercial Business loans $ 44,449 $ 60,986 $ 9,663 $ 23,905 $ — Energy loans 76,738 80,675 17,746 33,919 — Real estate Market risk 8,478 8,478 1,378 2,826 — Commercial 7,220 7,220 — 4,048 — Secured by 1-4 family 3,011 3,011 221 1,330 — Consumer 52 52 10 30 — Equipment leases — — — — — Total impaired loans $ 139,948 $ 160,422 $ 29,018 $ 66,058 $ — (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 — 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 — 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 — 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 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 March 31, 2019 Commercial Business loans $ 32,935 $ 13,524 $ 12,093 $ 58,552 $ 44,449 $ 8,869,686 $ 8,972,687 Energy 603 — — 603 76,738 1,623,932 1,701,273 Mortgage finance loans — — — — — 6,299,710 6,299,710 Construction Market risk 688 14,312 — 15,000 — 2,367,746 2,382,746 Commercial — — — — — 80,659 80,659 Secured by 1-4 family — — — — — 29,787 29,787 Real estate Market risk 5,030 607 — 5,637 8,478 2,546,670 2,560,785 Commercial 4,834 669 — 5,503 962 719,349 725,814 Secured by 1-4 family 7,748 — 86 7,834 3,011 345,122 355,967 Consumer 2,442 75 66 2,583 52 58,742 61,377 Equipment leases 1,697 — — 1,697 — 290,551 292,248 Total loans held for investment $ 55,977 $ 29,187 $ 12,245 $ 97,409 $ 133,690 $ 23,231,954 $ 23,463,053 (1) Loans past due 90 days and still accruing includes premium finance loans of $12.0 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 March 31, 2019 of loans that have been restructured during the three months ended March 31, 2019 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 Three months ended March 31, 2019 Commercial: Energy loans 1 $ 22,540 — $ — 1 $ 22,540

OREO and Valuation Allowance _2

OREO and Valuation Allowance for Losses on OREO (Tables)	3 Months Ended
	Mar. 31, 2019
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: Three months ended March 31, (in thousands) 2019 2018 Beginning balance $ 79 $ 11,742 Sales (79 ) (184 ) Valuation allowance for OREO — (2,000 ) Ending balance $ — $ 9,558

Certain Transfers of Financia_2

Certain Transfers of Financial Assets (Tables)	3 Months Ended
	Mar. 31, 2019
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: Three Months Ended March 31, Three Months Ended March 31, (in thousands) 2019 2018 Outstanding balance: Beginning balance(1) $ 1,949,785 $ 1,012,580 Loans purchased 1,550,059 1,479,006 Payments and loans sold (1,617,518 ) (1,399,683 ) Ending balance 1,882,326 1,091,903 Fair value adjustment: Beginning balance(1) 19,689 (1,576 ) Increase/(decrease) to fair value (378 ) (1,762 ) Ending balance 19,311 (3,338 ) Loans held for sale at fair value $ 1,901,637 $ 1,088,565 (1) Includes $299,000 of loans held for sale that are carried at lower of cost or market as of December 31, 2018 .
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: Three months ended March 31, (in thousands) 2019 2018 MSRs: Balance, beginning of year $ 42,474 $ 88,150 Capitalized servicing rights 6,138 16,750 Amortization (1,593 ) (2,741 ) Sales — (25,598 ) Balance, end of period $ 47,019 $ 76,561 Valuation allowance: Balance, beginning of year $ — $ 2,823 Increase (decrease) in valuation allowance 2,931 (2,823 ) Balance, end of period $ 2,931 $ — MSRs, net $ 44,088 $ 76,561 MSRs, fair value $ 44,691 $ 82,274
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: March 31, 2019 December 31, 2018 Average discount rates 9.54 % 9.55 % Expected prepayment speeds 12.07 % 9.77 % Weighted-average life, in years 6.1 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: (in thousands) March 31, 2019 December 31, 2018 50 bp adverse change in prepayment speed $ (6,407 ) $ (6,028 ) 100 bp adverse change in prepayment speed (10,989 ) (11,629 )

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Summary of lease cost and other information, operating leases	The table below summarizes our net lease cost: (in thousands) Three months ended Operating lease cost $ 3,516 Variable lease cost 903 Sublease income (31 ) Net lease cost $ 4,388 The table below summarizes other information related to our operating leases: (in thousands except for percent and period data) Three months ended Cash paid for amounts included in the measurement of lease liabilities Operating cash flows from operating leases $ 3,781 Right-of-use assets obtained in exchange for new finance lease liabilities 64,493 Weighted-average remaining lease term - operating leases, in years 5.9 Weighted-average discount rate - operating leases 2.8 %
Summary of maturity of remaining lease liabilities	The table below summarizes the maturity of remaining lease liabilities: (in thousands) March 31, 2019 2019 $ 10,878 2020 14,521 2021 14,236 2022 13,372 2023 12,400 2024 and thereafter 12,327 Total lease payments 77,734 Less: Interest (6,048 ) Present value of lease liabilities $ 71,686

Financial Instruments with Of_2

Financial Instruments with Off-Balance Sheet Risk (Tables)	3 Months Ended
	Mar. 31, 2019
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. Three months ended March 31, (in thousands) 2019 2018 Beginning balance of allowance for off-balance sheet credit losses $ 11,434 $ 9,071 Provision for off-balance sheet credit losses (1,639 ) 552 Ending balance of allowance for off-balance sheet credit losses $ 9,795 $ 9,623 (in thousands) March 31, 2019 December 31, 2018 Commitments to extend credit - period end balance $ 7,846,910 $ 8,030,198 Standby letters of credit - period end balance $ 265,125 $ 236,537

Regulatory Restrictions (Tables

Regulatory Restrictions (Tables)	3 Months Ended
	Mar. 31, 2019
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 March 31, 2019 CET1 Company $ 2,412,290 8.64 % N/A N/A $ 1,954,119 7.00 % N/A N/A Bank 2,426,687 8.70 % N/A N/A 1,953,530 7.00 % 1,813,992 6.50 % Total capital (to risk-weighted assets) Company 3,169,288 11.35 % N/A N/A 2,931,179 10.50 % N/A N/A Bank 3,025,046 10.84 % N/A N/A 2,930,295 10.50 % 2,790,757 10.00 % Tier 1 capital (to risk-weighted assets) Company 2,669,063 9.56 % N/A N/A 2,372,859 8.50 % N/A N/A Bank 2,583,460 9.26 % N/A N/A 2,372,143 8.50 % 2,232,605 8.00 % Tier 1 capital (to average assets)(1) Company 2,669,063 10.02 % N/A N/A 1,065,414 4.00 % N/A N/A Bank 2,583,460 9.70 % N/A N/A 1,064,951 4.00 % 1,331,188 5.00 % 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 % (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.

Stock-based Compensation (Table

Stock-based Compensation (Tables)	3 Months Ended
	Mar. 31, 2019
Compensation Related Costs [Abstract]
Schedule of stock-based compensation costs	The table below summarizes our stock-based compensation expense for the three months ended March 31, 2019 and 2018 : Three months ended March 31, (in thousands) 2019 2018 Stock-settled awards: SARs $ 6 $ 50 RSUs 2,407 1,896 Restricted stock 10 11 Cash-settled performance units 2,065 4,014 Total $ 4,488 $ 5,971
Schedule of unrecognized compensation costs	(in thousands except period data) March 31, 2019 Unrecognized compensation expense related to unvested stock-settled awards $ 30,167 Weighted average period over which expense is expected to be recognized, in years 3.3

Fair Value Disclosures (Tables)

Fair Value Disclosures (Tables)	3 Months Ended
	Mar. 31, 2019
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 March 31, 2019 Available-for-sale debt securities:(1) Residential mortgage-backed securities $ — $ 6,928 $ — Tax-exempt asset-backed securities — — 191,844 CRT securities — — 10,637 Equity securities(1)(2) 14,338 7,002 — Loans held for sale(3) — 1,888,591 13,046 Loans held for investment(4)(6) — — 39,719 Derivative assets(7) — 31,049 — Derivative liabilities(7) — 42,288 — Non-qualified deferred compensation plan liabilities(8) 14,548 — — 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 — — (1) Securities are measured at fair value on a recurring basis, generally monthly, except for tax-exempt asset-backed securities and CRT 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 corresponds 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: Net Realized/Unrealized Gains (Losses) (in thousands) Balance at Beginning of Period Purchases / Additions Sales / Reductions Realized Unrealized Balance at End of Period Three months ended March 31, 2019 Available-for-sale debt securities:(1) Tax-exempt asset-backed securities $ 95,804 $ 92,010 $ — $ — $ 4,030 $ 191,844 CRT securities $ — $ 15,044 $ — $ (331 ) $ (4,076 ) $ 10,637 Loans held for sale(2) $ 16,415 $ — $ (3,878 ) $ 216 $ 293 $ 13,046 Three months ended March 31, 2018 Loans held for sale(2) $ — $ 36,092 $ — $ — $ (1,841 ) $ 34,251 (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: March 31, 2019 December 31, 2018 (in thousands) Carrying Amount Estimated Fair Value Carrying Estimated Financial assets: Level 1 inputs: Cash and cash equivalents $ 2,331,292 $ 2,331,292 $ 3,080,065 $ 3,080,065 Investment securities 14,338 14,338 10,262 10,262 Level 2 inputs: Investment securities 13,930 13,930 14,150 14,150 Loans held for sale 1,888,591 1,888,591 1,953,059 1,953,059 Derivative assets 31,049 31,049 21,806 21,806 Level 3 inputs: Investment securities 202,481 202,481 95,804 95,804 Loans held for sale 13,046 13,046 16,415 16,415 Loans held for investment, net 23,152,727 23,152,057 22,376,552 22,347,876 Financial liabilities: Level 2 inputs: Federal funds purchased 886,426 886,426 629,169 629,169 Customer repurchase agreements 11,466 11,466 12,005 12,005 Other borrowings 3,600,000 3,600,000 3,900,000 3,900,000 Subordinated notes 281,858 289,179 281,767 283,349 Trust preferred subordinated debentures 113,406 113,406 113,406 113,406 Derivative liabilities 42,288 42,288 41,375 41,375 Level 3 inputs: Deposits 20,650,127 20,651,839 20,606,113 20,608,494

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2019
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: March 31, 2019 December 31, 2018 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 $ 1,590,394 $ 3,626 $ 27,508 $ 1,579,328 $ 7,978 $ 16,719 Commercial loan/lease interest rate caps 649,549 383 2 606,950 1,109 4 Foreign currency forward contracts 21,580 1,847 14 39,737 2,263 59 Customer counterparties: Commercial loan/lease interest rate swaps 1,590,394 27,508 3,626 1,579,328 16,719 7,978 Commercial loan/lease interest rate caps 649,549 2 383 606,950 4 1,109 Foreign currency forward contracts 21,580 14 1,847 39,737 59 2,263 Economic hedging interest rate derivatives: Loan purchase commitments 239,573 1,297 77 167,984 1,442 6 Forward sale commitments 1,623,500 — 12,459 1,928,527 — 21,005 Gross derivatives 34,677 45,916 29,574 49,143 Offsetting derivative assets/liabilities (3,628 ) (3,628 ) (7,768 ) (7,768 ) Net derivatives included in the consolidated balance sheets $ 31,049 $ 42,288 $ 21,806 $ 41,375
Schedule Of Weighted Average Interest Rate Received And Paid	The weighted-average received and paid interest rates for interest rate swaps outstanding were as follows: March 31, 2019 Weighted-Average Interest Rate December 31, 2018 Weighted-Average Interest Rate Received Paid Received Paid Non-hedging interest rate swaps 4.14 % 4.09 % 4.24 % 4.20 %

Operations and Summary of Sig_3

Operations and Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019
Property, Plant and Equipment [Line Items]
Operating lease ROU assets	$ 62,200
Operating lease liabilities	$ 71,686
Accounting Standards Update 2016-02
Property, Plant and Equipment [Line Items]
Operating lease ROU assets		$ 64,000
Operating lease liabilities		$ 74,000

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Numerator:
Net income	$ 82,839	$ 71,945
Preferred stock dividends	2,438	2,438
Net income available to common stockholders	$ 80,401	$ 69,507
Denominator:
Denominator for basic earnings per share—weighted average shares	50,229,797	49,650,884
Effect of employee stock-based awards	115,602	255,794
Effect of warrants to purchase common stock	0	446,819
Denominator for dilutive earnings per share—adjusted weighted average shares and assumed conversions	50,345,399	50,353,497
Basic earnings per common share	$ 1.60	$ 1.40
Diluted earnings per common share	$ 1.60	$ 1.38
Stock options excluded from computation of EPS	411,065	5,139

Investment Securities (Details)

Investment Securities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	$ 208,808		$ 102,392
Gross Unrealized Gains	4,677		654
Gross Unrealized Losses	(4,076)		0
Estimated Fair Value	209,409		103,046
Payments to acquire AFS securities, debt	109,928	$ 2,455
Residential mortgage-backed securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	6,567		6,874
Gross Unrealized Gains	361		368
Gross Unrealized Losses	0		0
Estimated Fair Value	6,928		7,242
Tax-exempt asset-backed securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	187,528		95,518
Gross Unrealized Gains	4,316		286
Gross Unrealized Losses	0		0
Estimated Fair Value	191,844		$ 95,804
Payments to acquire AFS securities, debt	92,000
Credit risk transfer securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	14,713
Gross Unrealized Gains	0
Gross Unrealized Losses	(4,076)
Estimated Fair Value	10,637
Payments to acquire AFS securities, debt	$ 15,000
Percentage of share of first losses	50.00%
Percentage of potential recovery on notes	100.00%

Investment Securities (Details

Investment Securities (Details 1) - USD ($)	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Amortized cost
Amortized Cost	$ 208,808,000	$ 102,392,000
Estimated fair value
Total	209,409,000	103,046,000
Investment securities	209,409,000	103,046,000
Weighted average yield
Debt Securities, Available-for-sale, Amortized Cost	$ 208,808,000	102,392,000
Available-for-sale Securities, Other Disclosure Items
Federal tax rate (percent)	21.00%
Customer repurchase agreements
Available-for-sale Securities, Other Disclosure Items
Available-for-sale debt securities pledged to secure certain customer repurchase agreements and deposits	$ 4,600,000	4,800,000
Residential mortgage-backed securities
Amortized cost
Less Than One Year	0	3,000
After One Through Five Years	1,419,000	1,573,000
After Five Through Ten Years	0	0
After Ten Years	5,148,000	5,298,000
Amortized Cost	6,567,000	6,874,000
Estimated fair value
Less Than One Year	0	4,000
After One Through Five Years	1,516,000	1,668,000
After Five Through Ten Years	0	0
After Ten Years	5,412,000	5,570,000
Investment securities	$ 6,928,000	$ 7,242,000
Weighted average yield
Less Than One Year	6.50%	6.50%
After One Through Five Years	5.54%	5.54%
After Five Through Ten Years	0.00%	0.00%
After Ten Years	4.59%	4.53%
Total	4.79%	4.76%
Debt Securities, Available-for-sale, Amortized Cost	$ 6,567,000	$ 6,874,000
Tax-exempt asset-backed securities
Amortized cost
Less Than One Year	0	0
After One Through Five Years	0	0
After Five Through Ten Years	0	0
After Ten Years	187,528,000	95,518,000
Amortized Cost	187,528,000	95,518,000
Estimated fair value
Less Than One Year	0	0
After One Through Five Years	0	0
After Five Through Ten Years	0	0
After Ten Years	191,844,000	95,804,000
Investment securities	$ 191,844,000	$ 95,804,000
Weighted average yield
Less Than One Year	0.00%	0.00%
After One Through Five Years	0.00%	0.00%
After Five Through Ten Years	0.00%	0.00%
After Ten Years	4.20%	4.25%
Total	4.20%	4.25%
Debt Securities, Available-for-sale, Amortized Cost	$ 187,528,000	$ 95,518,000
Credit risk transfer securities
Amortized cost
Less Than One Year	0
After One Through Five Years	0
After Five Through Ten Years	0
After Ten Years	14,713,000
Amortized Cost	14,713,000
Estimated fair value
Less Than One Year	0
After One Through Five Years	0
After Five Through Ten Years	0
After Ten Years	10,637,000
Investment securities	$ 10,637,000
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	2.49%
Total	2.49%
Debt Securities, Available-for-sale, Amortized Cost	$ 14,713,000
Less Than 12 Months, Fair Value	14,713,000
Less Than 12 Months, Unrealized Loss	(4,076,000)
12 Months or Longer, Fair Value	0
12 Months or Longer, Unrealized Loss	0
Total, Fair Value	14,713,000
Total, Unrealized Loss	(4,076,000)
Available-for-sale Securities, Other Disclosure Items
Other-than-temporary credit-related impairment	331,000
Deposits
Available-for-sale Securities, Other Disclosure Items
Available-for-sale debt securities pledged to secure certain customer repurchase agreements and deposits	$ 1,600,000	$ 1,700,000

Investment Securities (Detail_2

Investment Securities (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Debt Securities, Available-for-sale [Abstract]
Estimated fair value	$ 21,300		$ 17,200
Net gains/(losses) recognized during the period	1,266	$ (212)
Less: Realized net gains/(losses) recognized during the period on equity securities sold	(30)	0
Unrealized net gains/(losses) recognized during the period on equity securities still held	$ 1,296	$ (212)

Loans Held for Investment and_3

Loans Held for Investment and Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Loans and Leases Receivable, Net Reported Amount
Commercial	$ 10,673,960		$ 10,373,288
Mortgage finance(1)	6,299,710		5,877,524
Construction	2,493,192		2,120,966
Real estate	3,642,566		3,929,117
Consumer	61,377		63,438
Equipment leases	292,248		312,191
Gross loans held for investment	23,463,053	$ 20,533,737	22,676,524
Deferred income (net of direct origination costs)	(101,753)		(108,450)
Allowance for loan losses	(208,573)	(190,898)	(191,522)	$ (184,655)
Loans held for investment, net	23,152,727		$ 22,376,552
Proceeds from participations sold	$ 185,400	$ 193,000

Loans Held for Investment and_4

Loans Held for Investment and Allowance for Loan Losses (Details 1) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Financing Receivable, Allowance for Credit Losses [Line Items]
Average impaired loans outstanding	$ 66,058,000	$ 109,900,000	$ 105,138,000
Interest income recognized on non-accrual loans	0		133,000
Nonaccrual loans that met the criteria for restructured	$ 38,400,000		$ 20,000,000

Loans Held for Investment and_5

Loans Held for Investment and Allowance for Loan Losses (Details 2) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Financing Receivable, Recorded Investment [Line Items]
Commercial	$ 10,673,960	$ 10,373,288
Mortgage finance(1)	6,299,710	5,877,524
Construction	2,493,192	2,120,966
Real estate	3,642,566	3,929,117
Consumer	61,377	63,438
Equipment leases	292,248	312,191
Total	23,463,053	22,676,524	$ 20,533,737
Pass
Financing Receivable, Recorded Investment [Line Items]
Commercial	10,205,865	10,034,597
Mortgage finance(1)	6,299,710	5,877,524
Construction	2,478,880	2,099,955
Real estate	3,526,380	3,850,811
Consumer	59,759	61,815
Equipment leases	289,664	309,775
Total	22,860,258	22,234,477
Special mention
Financing Receivable, Recorded Investment [Line Items]
Commercial	200,920	120,531
Mortgage finance(1)	0	0
Construction	0	21,011
Real estate	75,755	47,644
Consumer	0	0
Equipment leases	1,975	2,223
Total	278,650	191,409
Substandard-accruing
Financing Receivable, Recorded Investment [Line Items]
Commercial	145,988	140,297
Mortgage finance(1)	0	0
Construction	14,312	0
Real estate	27,980	28,205
Consumer	1,566	1,568
Equipment leases	609	193
Total	190,455	170,263
Non-accrual
Financing Receivable, Recorded Investment [Line Items]
Commercial	121,187	77,863
Mortgage finance(1)	0	0
Construction	0	0
Real estate	12,451	2,457
Consumer	52	55
Equipment leases	0	0
Total	$ 133,690	$ 80,375

Loans Held for Investment and_6

Loans Held for Investment and Allowance for Loan Losses (Details 3) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 191,522	$ 184,655
Provision for loan losses	21,639	11,448
Charge-offs	4,865	5,667
Recoveries	277	462
Net charge-offs (recoveries)	4,588	5,205
Ending balance	208,573	190,898
Period end allowance for loan losses allocated to:
Loans individually evaluated for impairment	29,018	34,921
Loans collectively evaluated for impairment	179,555	155,977
Period end loans allocated to:
Loans individually evaluated for impairment	139,948	124,465
Loans collectively evaluated for impairment	23,323,105	20,409,272
Gross loans held for investment	23,463,053	20,533,737	$ 22,676,524
Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	129,442	118,806
Provision for loan losses	25,506	17,546
Charge-offs	4,865	5,667
Recoveries	266	360
Net charge-offs (recoveries)	4,599	5,307
Ending balance	150,349	131,045
Period end allowance for loan losses allocated to:
Loans individually evaluated for impairment	27,409	34,897
Loans collectively evaluated for impairment	122,940	96,148
Period end loans allocated to:
Loans individually evaluated for impairment	121,187	123,206
Loans collectively evaluated for impairment	10,552,773	9,337,818
Gross loans held for investment	10,673,960	9,461,024
Mortgage Finance
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	0	0
Provision for loan losses	1,300	0
Charge-offs	0	0
Recoveries	0	0
Net charge-offs (recoveries)	0	0
Ending balance	1,300	0
Period end allowance for loan losses allocated to:
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	1,300	0
Period end loans allocated to:
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	6,299,710	4,689,938
Gross loans held for investment	6,299,710	4,689,938
Construction
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	19,242	19,273
Provision for loan losses	3,583	(518)
Charge-offs	0	0
Recoveries	0	0
Net charge-offs (recoveries)	0	0
Ending balance	22,825	18,755
Period end allowance for loan losses allocated to:
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	22,825	18,755
Period end loans allocated to:
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	2,493,192	2,224,403
Gross loans held for investment	2,493,192	2,224,403
Real Estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	33,353	34,287
Provision for loan losses	(1,272)	(200)
Charge-offs	0	0
Recoveries	0	24
Net charge-offs (recoveries)	0	(24)
Ending balance	32,081	34,111
Period end allowance for loan losses allocated to:
Loans individually evaluated for impairment	1,599	22
Loans collectively evaluated for impairment	30,482	34,089
Period end loans allocated to:
Loans individually evaluated for impairment	18,709	1,187
Loans collectively evaluated for impairment	3,623,857	3,833,571
Gross loans held for investment	3,642,566	3,834,758
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	425	357
Provision for loan losses	(46)	(178)
Charge-offs	0	0
Recoveries	10	59
Net charge-offs (recoveries)	(10)	(59)
Ending balance	389	238
Period end allowance for loan losses allocated to:
Loans individually evaluated for impairment	10	2
Loans collectively evaluated for impairment	379	236
Period end loans allocated to:
Loans individually evaluated for impairment	52	72
Loans collectively evaluated for impairment	61,325	47,239
Gross loans held for investment	61,377	47,311
Equipment Leases
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,829	3,542
Provision for loan losses	(201)	(18)
Charge-offs	0	0
Recoveries	1	19
Net charge-offs (recoveries)	(1)	(19)
Ending balance	1,629	3,543
Period end allowance for loan losses allocated to:
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	1,629	3,543
Period end loans allocated to:
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	292,248	276,303
Gross loans held for investment	292,248	276,303
Additional Qualitative Reserve
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	7,231	8,390
Provision for loan losses	(7,231)	(5,184)
Charge-offs	0	0
Recoveries	0	0
Net charge-offs (recoveries)	0	0
Ending balance	0	3,206
Period end allowance for loan losses allocated to:
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	0	3,206
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 ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Recorded Investment
With No Related Allowanced Recorded, Recorded Investment	$ 38,571,000		$ 44,176,000
With An Allowanced Recorded, Recorded Investment	101,377,000		43,164,000
Combined, Recorded Investment	139,948,000		87,340,000
Unpaid Principal Balance
With No Related Allowanced Recorded, Unpaid Principal Balance	55,649,000		76,992,000
With An Allowanced Recorded, Unpaid Principal Balance	104,773,000		45,960,000
Combined, Unpaid Principal Balance	160,422,000		122,952,000
Related Allowance	29,018,000		8,310,000
Average Recorded Investment
With No Related Allowanced Recorded, Average Recorded Investment	22,673,000		37,510,000
With An Allowanced Recorded, Average Recorded Investment	43,385,000		67,628,000
Combined, Average Recorded Investment	66,058,000	$ 109,900,000	105,138,000
Interest Income Recognized
With No Related Allowanced Recorded, Interest Income Recognized	0		133,000
With An Allowanced Recorded, Interest Income Recognized	0		0
Interest income recognized on non-accrual loans	0		133,000
Commercial | Business loans
Recorded Investment
With No Related Allowanced Recorded, Recorded Investment	21,075,000		23,367,000
With An Allowanced Recorded, Recorded Investment	23,374,000		17,529,000
Combined, Recorded Investment	44,449,000		40,896,000
Unpaid Principal Balance
With No Related Allowanced Recorded, Unpaid Principal Balance	37,077,000		55,008,000
With An Allowanced Recorded, Unpaid Principal Balance	23,909,000		17,564,000
Combined, Unpaid Principal Balance	60,986,000		72,572,000
Related Allowance	9,663,000		4,679,000
Average Recorded Investment
With No Related Allowanced Recorded, Average Recorded Investment	12,218,000		16,426,000
With An Allowanced Recorded, Average Recorded Investment	11,687,000		41,307,000
Combined, Average Recorded Investment	23,905,000		57,733,000
Interest Income Recognized
With No Related Allowanced Recorded, Interest Income Recognized	0		133,000
With An Allowanced Recorded, Interest Income Recognized	0		0
Combined, Interest Income Recognized	0		133,000
Commercial | Energy loans
Recorded Investment
With No Related Allowanced Recorded, Recorded Investment	9,048,000		12,188,000
With An Allowanced Recorded, Recorded Investment	67,690,000		25,344,000
Combined, Recorded Investment	76,738,000		37,532,000
Unpaid Principal Balance
With No Related Allowanced Recorded, Unpaid Principal Balance	10,124,000		13,363,000
With An Allowanced Recorded, Unpaid Principal Balance	70,551,000		28,105,000
Combined, Unpaid Principal Balance	80,675,000		41,468,000
Related Allowance	17,746,000		3,573,000
Average Recorded Investment
With No Related Allowanced Recorded, Average Recorded Investment	5,724,000		17,135,000
With An Allowanced Recorded, Average Recorded Investment	28,195,000		25,672,000
Combined, Average Recorded Investment	33,919,000		42,807,000
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	8,478,000		0
Combined, Recorded Investment	8,478,000		0
Unpaid Principal Balance
With No Related Allowanced Recorded, Unpaid Principal Balance	0		0
With An Allowanced Recorded, Unpaid Principal Balance	8,478,000		0
Combined, Unpaid Principal Balance	8,478,000		0
Related Allowance	1,378,000		0
Average Recorded Investment
With No Related Allowanced Recorded, Average Recorded Investment	0		0
With An Allowanced Recorded, Average Recorded Investment	2,826,000		49,000
Combined, Average Recorded Investment	2,826,000		49,000
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	7,220,000		7,388,000
With An Allowanced Recorded, Recorded Investment	0		0
Combined, Recorded Investment	7,220,000		7,388,000
Unpaid Principal Balance
With No Related Allowanced Recorded, Unpaid Principal Balance	7,220,000		7,388,000
With An Allowanced Recorded, Unpaid Principal Balance	0		0
Combined, Unpaid Principal Balance	7,220,000		7,388,000
Related Allowance	0		0
Average Recorded Investment
With No Related Allowanced Recorded, Average Recorded Investment	4,048,000		3,215,000
With An Allowanced Recorded, Average Recorded Investment	0		83,000
Combined, Average Recorded Investment	4,048,000		3,298,000
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	1,228,000		1,233,000
With An Allowanced Recorded, Recorded Investment	1,783,000		236,000
Combined, Recorded Investment	3,011,000		1,469,000
Unpaid Principal Balance
With No Related Allowanced Recorded, Unpaid Principal Balance	1,228,000		1,233,000
With An Allowanced Recorded, Unpaid Principal Balance	1,783,000		236,000
Combined, Unpaid Principal Balance	3,011,000		1,469,000
Related Allowance	221,000		48,000
Average Recorded Investment
With No Related Allowanced Recorded, Average Recorded Investment	683,000		734,000
With An Allowanced Recorded, Average Recorded Investment	647,000		188,000
Combined, Average Recorded Investment	1,330,000		922,000
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	52,000		55,000
Combined, Recorded Investment	52,000		55,000
Unpaid Principal Balance
With No Related Allowanced Recorded, Unpaid Principal Balance	0		0
With An Allowanced Recorded, Unpaid Principal Balance	52,000		55,000
Combined, Unpaid Principal Balance	52,000		55,000
Related Allowance	10,000		10,000
Average Recorded Investment
With No Related Allowanced Recorded, Average Recorded Investment	0		0
With An Allowanced Recorded, Average Recorded Investment	30,000		54,000
Combined, Average Recorded Investment	30,000		54,000
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	0		275,000
Combined, Average Recorded Investment	0		275,000
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	Mar. 31, 2019USD ($)
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 97,409
Non-accrual	133,690
Current	23,231,954
Total	23,463,053
Premium finance loans past due and still accruing	12,000
Commercial | Business loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	58,552
Non-accrual	44,449
Current	8,869,686
Total	8,972,687
Commercial | Energy loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	603
Non-accrual	76,738
Current	1,623,932
Total	1,701,273
Mortgage Finance
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Non-accrual	0
Current	6,299,710
Total	6,299,710
Construction | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	15,000
Non-accrual	0
Current	2,367,746
Total	2,382,746
Construction | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Non-accrual	0
Current	80,659
Total	80,659
Construction | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Non-accrual	0
Current	29,787
Total	29,787
Real estate | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,637
Non-accrual	8,478
Current	2,546,670
Total	2,560,785
Real estate | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,503
Non-accrual	962
Current	719,349
Total	725,814
Real estate | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	7,834
Non-accrual	3,011
Current	345,122
Total	355,967
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,583
Non-accrual	52
Current	58,742
Total	61,377
Equipment leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,697
Non-accrual	0
Current	290,551
Total	292,248
30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	55,977
30 to 59 Days Past Due | Commercial | Business loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	32,935
30 to 59 Days Past Due | Commercial | Energy loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	603
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	688
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	0
30 to 59 Days Past Due | Real estate | Market risk
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,030
30 to 59 Days Past Due | Real estate | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,834
30 to 59 Days Past Due | Real estate | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	7,748
30 to 59 Days Past Due | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,442
30 to 59 Days Past Due | Equipment leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,697
60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	29,187
60 to 89 Days Past Due | Commercial | Business loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	13,524
60 to 89 Days Past Due | Commercial | Energy loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
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	14,312
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	607
60 to 89 Days Past Due | Real estate | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	669
60 to 89 Days Past Due | Real estate | Secured by 1-4 family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
60 to 89 Days Past Due | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	75
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	12,245
Greater Than 90 Days | Commercial | Business loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	12,093
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	86
Greater Than 90 Days | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	66
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	3 Months Ended
	Mar. 31, 2019USD ($)loan	Dec. 31, 2018USD ($)
Financing Receivable, Modifications [Line Items]
Nonaccrual loans that met the criteria for restructured	$ 38,400	$ 20,000
Commercial | Energy loans
Financing Receivable, Modifications [Line Items]
Number of Contracts | loan	1
Loans modified as restructured loans	$ 22,540
Commercial | Energy loans | Extended maturity
Financing Receivable, Modifications [Line Items]
Number of Contracts | loan	1
Loans modified as restructured loans	$ 22,540
Commercial | Energy loans | Adjusted payment schedule
Financing Receivable, Modifications [Line Items]
Number of Contracts | loan	0
Loans modified as restructured loans	$ 0

OREO and Valuation Allowance _3

OREO and Valuation Allowance for Losses on OREO (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Other Real Estate [Roll Forward]
Beginning balance	$ 79	$ 11,742
Sales	(79)	(184)
Valuation allowance for OREO	0	(2,000)
Ending balance	0	9,558
Other real estate owned write-down	$ 0	$ 2,000

Certain Transfers of Financia_3

Certain Transfers of Financial Assets Certain Transfers of Financial Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Outstanding balance:
Beginning balance(1)	$ 1,949,785	$ 1,012,580
Loans purchased	1,550,059	1,479,006
Payments and loans sold	(1,617,518)	(1,399,683)
Ending balance	1,882,326	1,091,903
Fair value adjustment:
Increase/(decrease) to fair value	(378)	(1,762)
Loans held for sale	1,901,637	1,088,565	$ 1,969,474
Fair value over (under) outstanding balance	$ 19,311	$ (3,338)	19,689	$ (1,576)
Small Business Administration Loans [Member]
Fair value adjustment:
Fair value over (under) outstanding balance			$ 299

Certain Transfers of Financia_4

Certain Transfers of Financial Assets (Details 1) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Loans and Leases Receivable Disclosure [Line Items]
Loans held for sale	$ 1,882,326,000	$ 1,091,903,000	$ 1,949,785,000	$ 1,012,580,000
Total Past Due	97,409,000
Estimated exposure related to servicing assets	1,600,000
Principal amount outstanding of loans in servicing portfolio	4,400,000,000		3,900,000,000
Escrow deposits related to servicing portfolio	49,600,000		37,900,000
Losses due to repurchase indemnification and make-whole obligations	162,000	$ 56,000
Greater Than 90 Days
Loans and Leases Receivable Disclosure [Line Items]
Loans held for sale	13,700,000		16,800,000
Total Past Due	12,245,000
Mortgage servicing rights
Loans and Leases Receivable Disclosure [Line Items]
Impairment charges	2,900,000
Government guarantees | Greater Than 90 Days
Loans and Leases Receivable Disclosure [Line Items]
Loans held for sale	12,500,000		16,000,000
Government guarantees | Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Greater Than 90 Days
Loans and Leases Receivable Disclosure [Line Items]
Total Past Due	317,000
Non-accrual
Loans and Leases Receivable Disclosure [Line Items]
Loans held for sale	$ 0		$ 0

Certain Transfers of Financia_5

Certain Transfers of Financial Assets (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Valuation Allowance for Impairment of Recognized Servicing Assets, Sales and Disposals [Abstract]
Valuation allowance, ending balance	$ 1,600
Mortgage Servicing Rights
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Balance, beginning of year	42,474	$ 88,150
Capitalized servicing rights	6,138	16,750
Amortization	(1,593)	(2,741)
Sales	0	(25,598)
Balance, end of period	47,019	76,561
Valuation Allowance for Impairment of Recognized Servicing Assets, Sales and Disposals [Abstract]
Valuation allowance, beginning balance	0	2,823
Increase (decrease) in valuation allowance	2,931	(2,823)
Valuation allowance, ending balance	2,931	0
MSRs, net	44,088	76,561
Fair value	$ 44,691	$ 82,274

Certain Transfers of Financia_6

Certain Transfers of Financial Assets (Details 3) - Mortgage Servicing Rights	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
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)	9.54%	9.55%
Expected prepayment speeds (percent)	12.07%	9.77%
Weighted-average life, in years	6 years 19 days	7 years

Certain Transfers of Financia_7

Certain Transfers of Financial Assets Certain Transfers of Financial Assets (Details 4) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Transfers and Servicing [Abstract]
50 bp adverse change in prepayment speed	$ (6,407)	$ (6,028)
100 bp adverse change in prepayment speed	$ (10,989)	$ (11,629)

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Thousands	Mar. 31, 2019USD ($)
Lessee, Lease, Description [Line Items]
Operating lease ROU assets	$ 62,200
Operating lease liabilities	71,686
Operating lease not yet commenced	$ 18,400
Minimum
Lessee, Lease, Description [Line Items]
Lease terms	1 year
Extension options	5 years
Maximum
Lessee, Lease, Description [Line Items]
Lease terms	11 years
Extension options	10 years

Leases - Net lease cost (Detail

Leases - Net lease cost (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Leases [Abstract]
Operating lease cost	$ 3,516
Variable lease cost	903
Sublease income	(31)
Net lease cost	$ 4,388

Leases - Other information (Det

Leases - Other information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Leases [Abstract]
Operating cash flows from operating leases	$ 3,781
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 64,493
Weighted-average remaining lease term - operating leases, in years	5 years 10 months 15 days
Weighted-average discount rate - operating leases	2.80%

Leases - Maturity of remaining

Leases - Maturity of remaining lease liabilities (Details) $ in Thousands	Mar. 31, 2019USD ($)
Leases [Abstract]
2019	$ 10,878
2020	14,521
2021	14,236
2022	13,372
2023	12,400
2024 and thereafter	12,327
Total lease payments	77,734
Less: Interest	(6,048)
Present value of lease liabilities	$ 71,686

Financial Instruments with Of_3

Financial Instruments with Off-Balance Sheet Risk (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Allowance For Off-Balance Sheet Credit Losses [Roll Forward]
Beginning balance of allowance for off-balance sheet credit losses	$ 11,434	$ 9,071
Provision for off-balance sheet credit losses	(1,639)	552
Ending balance of allowance for off-balance sheet credit losses	9,795	$ 9,623
Commitments to extend credit
Allowance For Off-Balance Sheet Credit Losses [Roll Forward]
Off-balance sheet liability	7,846,910		$ 8,030,198
Standby letters of credit
Allowance For Off-Balance Sheet Credit Losses [Roll Forward]
Off-balance sheet liability	$ 265,125		$ 236,537

Regulatory Restrictions (Detail

Regulatory Restrictions (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2009
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Assets	$ 28,383,111		$ 28,257,767		$ 15,000,000
Mortgage finance(1)	6,299,710		5,877,524
Mortgage Finance, Average Balance	$ 4,900,000
Common Equity Tier 1 [Abstract]
CET1, actual amount			2,412,290	$ 2,330,599
Total capital (to risk-weighted assets):
Total capital (to risk weighted assets), actual amount			3,169,288	3,074,097
Tier 1 capital (to risk-weighted assets):
Tier 1 capital (to risk-weighted assets), actual amount			2,669,063	2,589,374
Tier 1 capital (to average assets):
Tier 1 capital (to average assets), actual amount			$ 2,669,063	$ 2,589,374
Risk Based Ratios [Abstract]
CET1, actual ratio			8.64%	8.58%
Total capital (to risk weighted assets), actual ratio			11.35%	11.31%
Tier 1 capital (to risk-weighted assets), actual ratio			9.56%	9.53%
Tier 1 capital (to average assets), actual ratio			10.02%	9.87%
Bank
Common Equity Tier 1 [Abstract]
CET1, actual amount			$ 2,426,687	$ 2,340,988
CET1 to be well capitalized under prompt corrective action provisions, amount			1,813,992	1,765,915
Total capital (to risk-weighted assets):
Total capital (to risk weighted assets), actual amount			3,025,046	2,925,872
Total capital (to risk weighted assets) to be well capitalized under prompt corrective action provisions, amount			2,790,757	2,716,793
Tier 1 capital (to risk-weighted assets):
Tier 1 capital (to risk-weighted assets), actual amount			2,583,460	2,499,763
Tier 1 capital (to risk weighted assets) to be well capitalized under prompt corrective action provisions, amount			2,232,605	2,173,434
Tier 1 capital (to average assets):
Tier 1 capital (to average assets), actual amount			2,583,460	2,499,763
Tier 1 capital (to average assets) to be well capitalized under prompt corrective action provisions, amount			$ 1,331,188	$ 1,311,620
Risk Based Ratios [Abstract]
CET1, actual ratio			8.70%	8.62%
CET1 to be well capitalized under prompt corrective action provisions, ratio			6.50%	6.50%
Total capital (to risk weighted assets), actual ratio			10.84%	10.77%
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			9.26%	9.20%
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			9.70%	9.53%
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
Total capital (to risk-weighted assets):
Total capital (to risk weighted assets) for capital adequacy purposes, amount				2,683,679
Tier 1 capital (to risk-weighted assets):
Tier 1 capital (to risk-weighted assets) for capital adequacy purposes, amount				2,140,149
Tier 1 capital (to average assets):
Tier 1 capital (to average assets) for capital adequacy purposes, amount				$ 1,049,694
Risk Based Ratios [Abstract]
CET1 for capital adequacy purposes, ratio				6.38%
Total capital (to risk weighted assets) for capital adequacy purposes, ratio				9.88%
Tier 1 capital (to risk-weighted assets) for capital adequacy purposes, ratio				7.88%
Tier 1 capital (to average assets) for capital adequacy purposes, ratio				4.00%
Basel III, Phase-In Schedule | Bank
Common Equity Tier 1 [Abstract]
CET1 for capital adequacy purposes, amount				$ 1,731,955
Total capital (to risk-weighted assets):
Total capital (to risk weighted assets) for capital adequacy purposes, amount				2,682,833
Tier 1 capital (to risk-weighted assets):
Tier 1 capital (to risk-weighted assets) for capital adequacy purposes, amount				2,139,474
Tier 1 capital (to average assets):
Tier 1 capital (to average assets) for capital adequacy purposes, amount				$ 1,049,296
Risk Based Ratios [Abstract]
CET1 for capital adequacy purposes, ratio				6.38%
Total capital (to risk weighted assets) for capital adequacy purposes, ratio				9.88%
Tier 1 capital (to risk-weighted assets) for capital adequacy purposes, ratio				7.88%
Tier 1 capital (to average assets) for capital adequacy purposes, ratio				4.00%
Basel III, Phased-In
Common Equity Tier 1 [Abstract]
CET1 for capital adequacy purposes, amount			$ 1,954,119	$ 1,902,354
Total capital (to risk-weighted assets):
Total capital (to risk weighted assets) for capital adequacy purposes, amount			2,931,179	2,853,532
Tier 1 capital (to risk-weighted assets):
Tier 1 capital (to risk-weighted assets) for capital adequacy purposes, amount			2,372,859	2,310,002
Tier 1 capital (to average assets):
Tier 1 capital (to average assets) for capital adequacy purposes, amount			$ 1,065,414	$ 1,049,694
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%
Total capital (to risk weighted assets) to be well capitalized under prompt corrective action provisions, ratio		1.875%
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%
Tier 1 capital (to average assets) to be well capitalized under prompt corrective action provisions, ratio		2.50%
Basel III, Phased-In | Bank
Common Equity Tier 1 [Abstract]
CET1 for capital adequacy purposes, amount			$ 1,953,530	$ 1,901,755
Total capital (to risk-weighted assets):
Total capital (to risk weighted assets) for capital adequacy purposes, amount			2,930,295	2,852,632
Tier 1 capital (to risk-weighted assets):
Tier 1 capital (to risk-weighted assets) for capital adequacy purposes, amount			2,372,143	2,309,274
Tier 1 capital (to average assets):
Tier 1 capital (to average assets) for capital adequacy purposes, amount			$ 1,064,951	$ 1,049,296
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%

Stock-based Compensation (Detai

Stock-based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 4,488	$ 5,971
Unrecognized compensation expense related to unvested stock-settled awards	$ 30,167
Weighted average period over which unrecognized compensation expense is expected to be recognized (in years)	3 years 3 months 15 days
SARs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 6	50
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	2,407	1,896
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	10	11
Cash-settled performance units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 2,065	$ 4,014
Long-Term Incentive Plan 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized under the plan	2,550,000

Fair Value Disclosures (Details

Fair Value Disclosures (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	$ 209,409	$ 103,046
Investment securities	209,409	103,046
Loans held for sale	1,901,600	1,969,200
OREO	0	79	$ 9,558	$ 11,742
Tax-exempt asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	191,844	95,804
Credit risk transfer securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	10,637
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	14,548	10,148
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	0
Fair value measurements, recurring basis | Level 1 | Credit risk transfer 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	14,338	10,262
Fair value measurements, recurring basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	1,888,591	1,952,760
Derivative liabilities		41,375
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	6,928	7,242
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	0
Fair value measurements, recurring basis | Level 2 | Credit risk transfer 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	7,002	6,908
Fair value measurements, recurring basis | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	13,046	16,415
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	191,844	95,804
Fair value measurements, recurring basis | Level 3 | Credit risk transfer securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities	10,637
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
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
Fair value measurements, nonrecurring basis | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	39,719	29,885
OREO		79
Not Designated as Hedging Instrument [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		21,806
Derivative liabilities		41,375
Not Designated as Hedging Instrument [Member] | Fair value measurements, recurring basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	31,049	$ 21,806
Derivative liabilities	$ 42,288

Fair Value Disclosures (Detai_2

Fair Value Disclosures (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Tax-exempt asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at Beginning of Period	$ 95,804
Purchases / Additions	92,010
Sales / Reductions	0
Realized	0
Unrealized	4,030
Balance at End of Period	191,844
Credit risk transfer securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at Beginning of Period	0
Purchases / Additions	15,044
Sales / Reductions	0
Realized	(331)
Unrealized	(4,076)
Balance at End of Period	10,637
Loans held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at Beginning of Period	16,415	$ 0
Purchases / Additions	0	36,092
Sales / Reductions	(3,878)	0
Realized	216	0
Unrealized	293	(1,841)
Balance at End of Period	$ 13,046	$ 34,251

Fair Value Disclosures (Detai_3

Fair Value Disclosures (Details 2) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Impaired loans
Fair Value Assets Measured On Non Recurring Basis Unobservable Input Reconciliation [Line Items]
Asset measured on nonrecurring basis, carrying value	$ 53,000	$ 32,200
Asset measured on nonrecurring basis, specific valuation allowance	13,300	2,300
Asset measured on nonrecurring basis, reported fair value	$ 39,700	29,900
OREO
Fair Value Assets Measured On Non Recurring Basis Unobservable Input Reconciliation [Line Items]
Asset measured on nonrecurring basis, carrying value		$ 79
Measurement Input, Discount Rate
Fair Value Assets Measured On Non Recurring Basis Unobservable Input Reconciliation [Line Items]
Loans Held-for-sale, Measurement Input	0.932	0.929
Measurement Input, Discount Rate | Tax-exempt asset-backed securities
Fair Value Assets Measured On Non Recurring Basis Unobservable Input Reconciliation [Line Items]
Asset-Backed Securities, Measurement Input	0.0389	0.0421
Asset-Backed Securities, Term	8 years 4 months 15 days	9 years 2 months
Measurement Input, Discount Rate | Credit risk transfer securities
Fair Value Assets Measured On Non Recurring Basis Unobservable Input Reconciliation [Line Items]
Asset-Backed Securities, Measurement Input	0.0692
Asset-Backed Securities, Term	8 years 6 months 20 days

Fair Value Disclosures (Detai_4

Fair Value Disclosures (Details 3) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	$ 209,409	$ 103,046
Loans held for sale	1,901,600	1,969,200
Subordinated notes	281,858	281,767
Level 1 | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	14,338	10,262
Level 1 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	2,331,292	3,080,065
Investment securities	14,338	10,262
Level 2 | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	13,930	14,150
Loans held for sale	1,888,591	1,953,059
Derivative assets		21,806
Federal funds purchased	886,426	629,169
Customer repurchase agreements	11,466	12,005
Other borrowings	3,600,000	3,900,000
Subordinated notes	281,858	281,767
Derivative liabilities		41,375
Level 2 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	13,930	14,150
Loans held for sale	1,888,591	1,953,059
Derivative assets	31,049	21,806
Federal funds purchased	886,426	629,169
Customer repurchase agreements	11,466	12,005
Other borrowings	3,600,000	3,900,000
Subordinated notes	289,179	283,349
Derivative liabilities	42,288	41,375
Level 3 | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities	202,481	95,804
Loans held for sale	13,046	16,415
Loans held for investment, net	23,152,727	22,376,552
Deposits	20,650,127	20,606,113
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	202,481	95,804
Loans held for sale	13,046	16,415
Loans held for investment, net	23,152,057	22,347,876
Deposits	20,651,839	20,608,494
Trust preferred subordinated debentures	$ 113,406	$ 113,406

Derivative Financial Instrume_3

Derivative Financial Instruments (Details 1) - Non-hedging - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Estimated fair value, asset derivative	$ 34,677	$ 29,574
Estimated fair value, liability derivative	45,916	49,143
Offsetting derivative liabilities	(3,628)	(7,768)
Offsetting derivative assets	(3,628)	(7,768)
Net asset derivatives included in the consolidated balance sheets		21,806
Net liability derivatives included in the consolidated balance sheets		41,375
Interest rate contract | Loan purchase commitments
Derivative [Line Items]
Notional amount	239,573	167,984
Estimated fair value, asset derivative	1,297	1,442
Estimated fair value, liability derivative	77	6
Interest rate contract | Loan purchase commitments
Derivative [Line Items]
Notional amount	1,623,500	1,928,527
Estimated fair value, asset derivative	0	0
Estimated fair value, liability derivative	12,459	21,005
Financial institution counterparties | Commercial loan/lease | Interest rate swap
Derivative [Line Items]
Notional amount	1,590,394	1,579,328
Estimated fair value, asset derivative	3,626	7,978
Estimated fair value, liability derivative	27,508	16,719
Financial institution counterparties | Commercial loan/lease | Interest rate cap
Derivative [Line Items]
Notional amount	649,549	606,950
Estimated fair value, asset derivative	383	1,109
Estimated fair value, liability derivative	2	4
Financial institution counterparties | Commercial loan/lease | Foreign currency forward contracts
Derivative [Line Items]
Notional amount	21,580	39,737
Estimated fair value, asset derivative	1,847	2,263
Estimated fair value, liability derivative	14	59
Customer counterparties | Commercial loan/lease | Interest rate swap
Derivative [Line Items]
Notional amount	1,590,394	1,579,328
Estimated fair value, asset derivative	27,508	16,719
Estimated fair value, liability derivative	3,626	7,978
Customer counterparties | Commercial loan/lease | Interest rate cap
Derivative [Line Items]
Notional amount	649,549	606,950
Estimated fair value, asset derivative	2	4
Estimated fair value, liability derivative	383	1,109
Customer counterparties | Commercial loan/lease | Foreign currency forward contracts
Derivative [Line Items]
Notional amount	21,580	39,737
Estimated fair value, asset derivative	14	59
Estimated fair value, liability derivative	$ 1,847	$ 2,263

Derivative Financial Instrume_4

Derivative Financial Instruments Derivative Financial Instruments (Details 2) - Non-hedging - Commercial loan/lease - Interest rate swap	Mar. 31, 2019	Dec. 31, 2018
Interest rate received
Derivative [Line Items]
Weighted average fixed interest rate	4.14%	4.24%
Interest rate paid
Derivative [Line Items]
Weighted average fixed interest rate	4.09%	4.20%

Derivative Financial Instrume_5

Derivative Financial Instruments Derivative Financial Instruments (Details 3) $ in Millions	Mar. 31, 2019USD ($)instrument	Dec. 31, 2018USD ($)instrument
Derivative [Line Items]
Cash collateral pledged for derivatives	$ 43.5	$ 25.3
Risk participation agreement - participant bank
Derivative [Line Items]
Instruments held | instrument	12	13
Maximum exposure	$ 2.2	$ 1.5
Notional amount	$ 144.7	$ 149.1
Risk participation agreement - lead bank
Derivative [Line Items]
Instruments held | instrument	10	9
Notional amount	$ 124.3	$ 114.8
Non-hedging | Commercial loan/lease
Derivative [Line Items]
Credit risk exposure, net of collateral pledged, relating to derivatives	$ 30	$ 18.7
Non-hedging | Interest rate cap | Commercial loan/lease
Derivative [Line Items]
Weighted average fixed interest rate	3.22%	3.20%
Interest-bearing deposits
Derivative [Line Items]
Cash collateral pledged for derivatives	$ 31.7	$ 11.2
Other assets
Derivative [Line Items]
Cash collateral pledged for derivatives	$ 11.8	$ 14.1

Uncategorized Items - tcbi-2019

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