Independent Bank (IBTX) 10-Q 27 Apr 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2017	Apr. 26, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1
Trading Symbol	IBTX
Entity Registrant Name	Independent Bank Group, Inc.
Entity Central Index Key	1,564,618
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		27,780,224

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Assets
Cash and due from banks	$ 162,985	$ 158,686
Interest-bearing deposits in other banks	342,138	336,341
Federal funds sold	10,000	10,000
Cash and cash equivalents	515,123	505,027
Certificates of deposit held in other banks	5,892	2,707
Securities available for sale, at fair value	350,409	316,435
Loans held for sale	5,081	9,795
Loans, net	4,666,653	4,539,063
Premises and equipment, net	88,286	89,898
Other real estate owned	2,896	1,972
Federal Home Loan Bank (FHLB) of Dallas stock and other restricted stock	26,672	26,536
Bank-owned life insurance (BOLI)	57,608	57,209
Deferred tax asset	7,950	9,631
Goodwill	258,319	258,319
Core deposit intangible, net	13,685	14,177
Other assets	24,040	22,032
Total assets	6,022,614	5,852,801
Deposits:
Noninterest-bearing	1,126,113	1,117,927
Interest-bearing	3,596,090	3,459,182
Total deposits	4,722,203	4,577,109
FHLB advances	460,727	460,746
Other borrowings	107,388	107,299
Junior subordinated debentures	18,147	18,147
Other liabilities	25,680	17,135
Total liabilities	5,334,145	5,180,436
Commitments and contingencies
Stockholders’ equity:
Preferred stock (0 and 0 shares outstanding, respectively)	0	0
Common stock (18,925,182 and 18,870,312 shares outstanding, respectively)	189	189
Additional paid-in capital	556,350	555,325
Retained earnings	131,730	117,951
Accumulated other comprehensive income (loss)	200	(1,100)
Total stockholders’ equity	688,469	672,365
Total liabilities and stockholders’ equity	$ 6,022,614	$ 5,852,801

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - shares	Mar. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Preferred stock, shares issued (shares)	0	0
Preferred stock, shares outstanding (shares)	0	0
Common stock, shares outstanding (shares)	18,925,182	18,870,312

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Interest income:
Interest and fees on loans	$ 53,744	$ 49,910
Interest on taxable securities	764	730
Interest on nontaxable securities	541	451
Interest on interest-bearing deposits and other	890	373
Total interest income	55,939	51,464
Interest expense:
Interest on deposits	5,029	3,651
Interest on FHLB advances	1,171	1,001
Interest on repurchase agreements and other borrowings	1,705	1,003
Interest on junior subordinated debentures	167	149
Total interest expense	8,072	5,804
Net interest income	47,867	45,660
Provision for loan losses	2,023	2,997
Net interest income after provision for loan losses	45,844	42,663
Noninterest income:
Service charges on deposit accounts	1,927	1,695
Mortgage fee income	1,267	1,376
Gain on sale of other real estate	0	43
Gain on sale of premises and equipment	5	38
Increase in cash surrender value of BOLI	399	265
Other	985	1,053
Total noninterest income	4,583	4,470
Noninterest expense:
Salaries and employee benefits	16,837	16,774
Occupancy	3,872	4,040
Data processing	1,288	1,182
FDIC assessment	878	726
Advertising and public relations	297	295
Communications	475	535
Net other real estate owned expenses (including taxes)	37	33
Other real estate impairment	0	55
Core deposit intangible amortization	492	488
Professional fees	773	660
Acquisition expense, including legal	146	639
Other	2,933	3,092
Total noninterest expense	28,028	28,519
Income before taxes	22,399	18,614
Income tax expense	6,728	6,162
Net income	$ 15,671	$ 12,452
Basic earnings per share (usd per share)	$ 0.83	$ 0.67
Diluted earnings per share (usd per share)	$ 0.82	$ 0.67

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 15,671	$ 12,452
Other comprehensive income before tax:
Change in net unrealized gains on available for sale securities during the year	2,000	1,205
Reclassification adjustment for gain on sale of securities available for sale included in net income	0	0
Other comprehensive income before tax	2,000	1,205
Income tax expense	700	422
Other comprehensive income, net of tax	1,300	783
Comprehensive income	$ 16,971	$ 13,235

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock $.01 Par Value 10 million shares authorized	Common Stock $.01 Par Value 100 million shares authorized	Additional Paid in Capital	Retained Earnings	Accumulated Other Comprehensive Income (loss)
Beginning balance (shares) at Dec. 31, 2015			18,399,194
Beginning balance at Dec. 31, 2015	$ 603,371	$ 0	$ 184	$ 530,107	$ 70,698	$ 2,382
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	12,452				12,452
Other comprehensive income, net of tax	783					783
Restricted stock granted (shares)			67,820
Restricted stock granted	0		$ 1	(1)
Stock based compensation expense	1,220			1,220
Dividends ($0.10 per share in 2017 and $0.08 in 2016)	(1,477)				(1,477)
Restricted stock forfeited (shares)			(5,534)
Restricted stock forfeited	0			0	0
Income tax deficiency on restricted stock vested	(83)			(83)
Preferred stock dividends	(8)				(8)
Ending balance (shares) at Mar. 31, 2016			18,461,480
Ending balance at Mar. 31, 2016	616,258	0	$ 185	531,243	81,665	3,165
Beginning balance (shares) at Dec. 31, 2015			18,399,194
Beginning balance at Dec. 31, 2015	603,371	0	$ 184	530,107	70,698	2,382
Ending balance (shares) at Dec. 31, 2016			18,870,312
Ending balance at Dec. 31, 2016	672,365	0	$ 189	555,325	117,951	(1,100)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	15,671				15,671
Other comprehensive income, net of tax	1,300					1,300
Restricted stock granted (shares)			51,667
Restricted stock granted	0		$ 0	0
Stock based compensation expense	970			970
Exercise of warrants (in shares)			3,203
Exercise of warrants	55			55
Dividends ($0.10 per share in 2017 and $0.08 in 2016)	(1,892)				(1,892)
Ending balance (shares) at Mar. 31, 2017			18,925,182
Ending balance at Mar. 31, 2017	$ 688,469	$ 0	$ 189	$ 556,350	$ 131,730	$ 200

Consolidated Statements of Cha7

Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Stockholders' Equity [Abstract]
Dividends paid (usd per share)	$ 0.10	$ 0.08
Common stock par value (usd per share)	$ 0.01	$ 0.01
Common stock shares authorized (shares)	100,000,000	100,000,000
Preferred stock par value (usd per share)	$ 0.01	$ 0.01
Preferred stock shares authorized (shares)	10,000,000	10,000,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 15,671	$ 12,452
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation expense	1,763	1,639
Accretion income recognized on acquired loans	(480)	(2,217)
Amortization of core deposit intangibles	492	488
Amortization of premium on securities, net	721	377
Amortization of discount and origination costs on other borrowings	89	32
Stock based compensation expense	970	1,220
Excess tax benefit on restricted stock vested	(724)	0
FHLB stock dividends	(88)	(36)
Gain on sale of premises and equipment	(5)	(38)
Gain recognized on other real estate transactions	0	(43)
Impairment of other real estate	0	55
Deferred tax expense	981	594
Provision for loan losses	2,023	2,997
Increase in cash surrender value of life insurance	(399)	(265)
Loans originated for sale	(51,631)	(49,481)
Proceeds from sale of loans	56,345	53,265
Net change in other assets	(2,008)	1,294
Net change in other liabilities	3,201	780
Net cash provided by operating activities	26,921	23,113
Cash flows from investing activities:
Proceeds from maturities, calls and pay downs of securities available for sale	17,241	16,479
Purchases of securities available for sale	(43,868)	(44,838)
Purchases of certificates held in other banks	(3,185)	0
Maturities of certificates held in other banks	0	22,412
Net purchases of FHLB stock	(48)	(8,108)
Net loans originated	(129,883)	(137,809)
Additions to premises and equipment	(155)	(1,269)
Proceeds from sale of premises and equipment	9	84
Proceeds from sale of other real estate owned	0	411
Capitalized additions to other real estate owned	(174)	0
Net cash used in investing activities	(160,063)	(152,638)
Cash flows from financing activities:
Net increase in demand deposits, NOW and savings accounts	141,116	163,847
Net increase (decrease) in time deposits	3,978	(40,862)
Proceeds from FHLB advances	0	225,000
Repayments of FHLB advances	(19)	(132,520)
Net change in repurchase agreements	0	8,528
Repayments of other borrowings	0	(5,798)
Proceeds from exercise of common stock warrants	55	0
Redemption of preferred stock	0	(23,938)
Dividends paid	(1,892)	(1,485)
Net cash provided by financing activities	143,238	192,772
Net change in cash and cash equivalents	10,096	63,247
Cash and cash equivalents at beginning of year	505,027	293,279	$ 293,279
Cash and cash equivalents at end of period	$ 515,123	$ 356,526	$ 505,027

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Nature of Operations: Independent Bank Group, Inc. (IBG) through its subsidiary, Independent Bank, a Texas state banking corporation (Bank) (collectively known as the Company), provides a full range of banking services to individual and corporate customers in the North Texas, Central Texas and Houston areas through its various branch locations in those areas. The Company is engaged in traditional community banking activities, which include commercial and retail lending, deposit gathering, investment and liquidity management activities. The Company’s primary deposit products are demand deposits, money market accounts and certificates of deposit, and its primary lending products are commercial business and real estate, real estate mortgage and consumer loans. Basis of Presentation: The accompanying consolidated financial statements include the accounts of IBG, its wholly-owned subsidiaries, the Bank and IBG Adriatica Holdings, Inc. (Adriatica) and the Bank’s wholly-owned subsidiaries, IBG Real Estate Holdings, Inc., IBG Aircraft Company III, Preston Grand, Inc, and McKinney Avenue Holdings, Inc. and its wholly owned subsidiary, McKinney Avenue SPE 1, Inc. Adriatica, McKinney Avenue Holdings, Inc. and its subsidiary are currently not active entities. All material intercompany transactions and balances have been eliminated in consolidation. In addition, the Company wholly-owns IB Trust I (Trust I), IB Trust II (Trust II), IB Trust III (Trust III), IB Centex Trust I (Centex Trust I) and Community Group Statutory Trust I (CGI Trust I). The Trusts were formed to issue trust preferred securities and do not meet the criteria for consolidation. The consolidated interim financial statements are unaudited, but include all adjustments, which, in the opinion of management, are necessary for a fair presentation of the results of the periods presented. All such adjustments were of a normal and recurring nature. These financial statements should be read in conjunction with the financial statements and the notes thereto in the Company's Annual Report of Form10-K for the year ended December 31, 2016. The consolidated statement of condition at December 31, 2016 had been derived from the audited financial statements as of that date, but does not include all of the information and footnotes required by accounting principles generally accepted in the United States of America for complete financial statements. Segment Reporting: The Company has one reportable segment. The Company’s chief operating decision-maker uses consolidated results to make operating and strategic decisions. Reclassifications: Certain prior period financial statement amounts have been reclassified to conform to current period presentation. The reclassifications have no effect on net income or stockholders' equity as previously reported. New Accounting Pronouncement: ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting was effective for the Company on January 1, 2017. ASU 2016-09 requires that all income tax effects related to vestings of share-based payment awards be reported in earnings as an increase (or decrease) to income tax expense. Previously, excess income tax benefits of a vested award were reported as an increase (or decrease) to additional paid-in capital to the extent that those benefits were greater than (or less than) the income tax benefits recognized in earnings during the award's vesting period. The requirement to report those income tax effects in earnings has been applied to vestings occurring on or after January 1, 2017 and resulted in recording a $724 thousand tax benefit for the period ended March 31, 2017. ASU 2016-09 also requires that all income tax-related cash flows resulting from share-based payments be reported as operating activities in the statement of cash flows. We have elected to apply that change in cash flow classification on a prospective basis. The impact of this change and that of the remaining provisions of ASU 2016-09 did not have significant impact on our financial statements. Subsequent events: Companies are required to evaluate events and transactions that occur after the balance sheet date but before the date the financial statements are issued. They must recognize in the financial statements the effect of all events or transactions that provide additional evidence of conditions that existed at the balance sheet date, including the estimates inherent in the financial statement preparation process. Entities shall not recognize the impact of events or transactions that provide evidence about conditions that did not exist at the balance sheet date but arose after that date. The Company has evaluated subsequent events through the date of filing these financial statements with the Securities and Exchange Commission (SEC) and noted no subsequent events requiring financial statement recognition or disclosure, except as disclosed in Note 10. Earnings per share: Basic earnings per common share are net income available to common shareholders divided by the weighted average number of common shares outstanding during the period. The unvested share-based payment awards that contain rights to non forfeitable dividends are considered participating securities for this calculation. Diluted earnings per common share include the dilutive effect of additional potential common shares issuable under stock warrants. The participating nonvested common stock was not included in dilutive shares as it was anti-dilutive for the three months ended March 31, 2017. Proceeds from the assumed exercise of dilutive stock warrants are assumed to be used to repurchase common stock at the average market price. The following table presents a reconciliation of net income available to common shareholders and the number of shares used in the calculation of basic and diluted earnings per common share. Three Months Ended March 31, 2017 2016 Basic earnings per share: Net income $ 15,671 $ 12,452 Less: Preferred stock dividends — (8 ) Net income after preferred stock dividends 15,671 12,444 Less: Undistributed earnings allocated to participating securities 176 211 Dividends paid on participating securities 24 28 Net income available to common shareholders $ 15,471 $ 12,205 Weighted-average basic shares outstanding 18,667,274 18,089,853 Basic earnings per share $ 0.83 $ 0.67 Diluted earnings per share: Net income available to common shareholders $ 15,471 $ 12,205 Total weighted-average basic shares outstanding 18,667,274 18,089,853 Add dilutive stock warrants 107,132 61,492 Add dilutive participating securities — 22,255 Total weighted-average diluted shares outstanding 18,774,406 18,173,600 Diluted earnings per share $ 0.82 $ 0.67 Anti-dilutive participating securities 126,847 —

Statement of Cash Flows

Statement of Cash Flows	3 Months Ended
	Mar. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Statement of Cash Flows	Statement of Cash Flows As allowed by the accounting standards, the Company has chosen to report on a net basis its cash receipts and cash payments for time deposits accepted and repayments of those deposits, and loans made to customers and principal collections on those loans. The Company uses the indirect method to present cash flows from operating activities. Other supplemental cash flow information is presented below: Three Months Ended March 31, 2017 2016 Cash transactions: Interest expense paid $ 9,694 $ 6,823 Income taxes paid $ — $ 760 Noncash transactions: Transfers of loans to other real estate owned $ 750 $ — Securities purchased, not yet settled $ 6,068 $ — Excess tax deficiency on restricted stock vested $ — $ (83 ) Transfer of repurchase agreements to deposits $ — $ 20,688 The supplemental schedule of noncash investing activities from Company acquisition activity includes the following measurement-period adjustments made during the period: Three Months Ended March 31, 2017 2016 Assets acquired: Loans $ — $ 735 Goodwill — (324 ) Core deposit intangibles — (216 ) Deferred tax asset — (175 ) Total assets $ — $ 20 Liabilities assumed: Other liabilities — 20 Total liabilities $ — $ 20

Securities Available for Sale

Securities Available for Sale	3 Months Ended
	Mar. 31, 2017
Available-for-sale Securities [Abstract]
Securities Available for Sale	Securities Available for Sale Securities available for sale have been classified in the consolidated balance sheets according to management’s intent. The amortized cost of securities and their approximate fair values at March 31, 2017 and December 31, 2016, are as follows: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Securities Available for Sale March 31, 2017 U. S. treasuries $ 3,196 $ — $ (38 ) $ 3,158 Government agency securities 136,621 165 (1,078 ) 135,708 Obligations of state and municipal subdivisions 103,554 1,259 (1,447 ) 103,366 Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC 107,643 1,085 (551 ) 108,177 $ 351,014 $ 2,509 $ (3,114 ) $ 350,409 December 31, 2016 U.S. treasuries $ 3,208 $ — $ (61 ) $ 3,147 Government agency securities 123,605 141 (1,479 ) 122,267 Obligations of state and municipal subdivisions 88,358 920 (2,022 ) 87,256 Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC 103,869 928 (1,032 ) 103,765 $ 319,040 $ 1,989 $ (4,594 ) $ 316,435 Securities with a carrying amount of approximately $ 169,770 and $ 176,457 at March 31, 2017 and December 31, 2016, respectively, were pledged to secure public fund deposits and repurchase agreements. There were no sales of securities during the three months ended March 31, 2017 and 2016. The amortized cost and estimated fair value of securities available for sale at March 31, 2017 , by contractual maturity, are shown below. Maturities of pass-through certificates will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. March 31, 2017 Securities Available for Sale Amortized Cost Fair Value Due in one year or less $ 31,149 $ 31,132 Due from one year to five years 113,221 112,685 Due from five to ten years 37,014 36,601 Thereafter 61,987 61,814 243,371 242,232 Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC 107,643 108,177 $ 351,014 $ 350,409 The number of securities, unrealized losses and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, as of March 31, 2017 and December 31, 2016, are summarized as follows: Less Than 12 Months Greater Than 12 Months Total Description of Securities Number of Securities Estimated Fair Value Unrealized Losses Number of Securities Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses Securities Available for Sale March 31, 2017 U.S. treasuries 1 $ 3,158 $ (38 ) — $ — $ — $ 3,158 $ (38 ) Government agency securities 45 104,389 (1,072 ) 1 995 (6 ) 105,384 (1,078 ) Obligations of state and municipal subdivisions 76 38,076 (1,418 ) 5 2,185 (29 ) 40,261 (1,447 ) Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC 28 70,714 (551 ) — — — 70,714 (551 ) 150 $ 216,337 $ (3,079 ) 6 $ 3,180 $ (35 ) $ 219,517 $ (3,114 ) December 31, 2016 U.S. treasuries 1 $ 3,147 $ (61 ) — $ — $ — $ 3,147 $ (61 ) Government agency securities 43 102,044 (1,472 ) 1 993 (7 ) 103,037 (1,479 ) Obligations of state and municipal subdivisions 100 46,186 (2,011 ) 4 1,549 (11 ) 47,735 (2,022 ) Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC 30 67,868 (1,032 ) — — — 67,868 (1,032 ) 174 $ 219,245 $ (4,576 ) 5 $ 2,542 $ (18 ) $ 221,787 $ (4,594 ) Unrealized losses are generally due to changes in interest rates. The Company has the intent to hold these securities until maturity or a forecasted recovery, and it is more likely than not that the Company will not have to sell the securities before the recovery of their cost basis. As such, the losses are deemed to be temporary.

Loans, Net and Allowance for Lo

Loans, Net and Allowance for Loan Losses	3 Months Ended
	Mar. 31, 2017
Receivables [Abstract]
Loans, Net and Allowance for Loan Losses	Loans, Net and Allowance for Loan Losses Loans, net, at March 31, 2017 and December 31, 2016, consisted of the following: March 31, December 31, 2017 2016 Commercial $ 601,985 $ 630,805 Real estate: Commercial 2,562,743 2,459,221 Commercial construction, land and land development 573,623 531,481 Residential 647,569 634,545 Single family interim construction 237,740 235,475 Agricultural 52,515 53,548 Consumer 26,224 27,530 Other 112 166 4,702,511 4,572,771 Deferred loan fees (2,427 ) (2,117 ) Allowance for loan losses (33,431 ) (31,591 ) $ 4,666,653 $ 4,539,063 The Company has certain lending policies and procedures in place that are designed to maximize loan income within an acceptable level of risk. Management reviews and approves these policies and procedures on a regular basis. A reporting system supplements the review process by providing management with frequent reports related to loan production, loan quality, concentrations of credit, loan delinquencies and non-performing and potential problem loans. Commercial loans are underwritten after evaluating and understanding the borrower’s ability to operate profitably and prudently expand its business. The Company’s management examines current and projected cash flows to determine the ability of the borrower to repay their obligations as agreed. Commercial loans are primarily made based on the identified cash flows of the borrower and secondarily on the underlying collateral provided by the borrower. These cash flows, however, may not be as expected and the value of collateral securing the loans may fluctuate. Most commercial loans are secured by the assets being financed or other business assets such as accounts receivable or inventory and may incorporate a personal guarantee; however, some short term loans may be made on an unsecured basis. Additionally, our commercial loan portfolio includes loans made to customers in the energy industry, which is a complex, technical and cyclical industry. Experienced bankers with specialized energy lending experience originate our energy loans. Companies in this industry produce, extract, develop, exploit and explore for oil and natural gas. Loans are primarily collateralized with proven producing oil and gas reserves based on a technical evaluation of these reserves. At March 31, 2017 and December 31, 2016, there were approximately $ 97.2 million and $ 115.3 million of exploration and production (E&P) energy loans outstanding, respectively. Commercial real estate loans are subject to underwriting standards and processes similar to commercial loans. These loans are viewed primarily as cash flow loans and secondarily as loans secured by real estate. Commercial real estate lending typically involves higher loan principal amounts, and the repayment of these loans is generally largely dependent on the successful operation of the property or the business conducted on the property securing the loan. Commercial real estate loans may be more adversely affected by conditions in the real estate markets or in the general economy. The properties securing the Company’s commercial real estate portfolio are diverse in terms of type and geographic location. Management monitors the diversification of the portfolio on a quarterly basis by type and geographic location. Management also tracks the level of owner occupied property versus non owner occupied property. Land and commercial land development loans are underwritten using feasibility studies, independent appraisal reviews and financial analysis of the developers or property owners. Generally, borrowers must have a proven track record of success. Commercial construction loans are generally based upon estimates of cost and value of the completed project. These estimates may not be accurate. Commercial construction loans often involve the disbursement of substantial funds with the repayment dependent on the success of the ultimate project. Sources of repayment for these loans may be pre-committed permanent financing or sale of the developed property. The loans in this portfolio are geographically diverse and due to the increased risk are monitored closely by management and the board of directors on a quarterly basis. Residential real estate and single family interim construction loans are underwritten primarily based on borrowers’ credit scores, documented income and minimum collateral values. Relatively small loan amounts are spread across many individual borrowers, which minimizes risk in the residential portfolio. In addition, management evaluates trends in past dues and current economic factors on a regular basis. Agricultural loans are collateralized by real estate and/or agricultural-related assets. Agricultural real estate loans are primarily comprised of loans for the purchase of farmland. Loan-to-value ratios on loans secured by farmland generally do not exceed 80% and have amortization periods limited to twenty years. Agricultural non-real estate loans are generally comprised of term loans to fund the purchase of equipment, livestock and seasonal operating lines to grain farmers to plant and harvest corn and soybeans. Specific underwriting standards have been established for agricultural-related loans, including the establishment of projections for each operating year based on industry developed estimates of farm input costs and expected commodity yields and prices. Operating lines are typically written for one year and secured by the crop and other farm assets as considered necessary. Agricultural loans carry significant credit risks as they involve larger balances concentrated with single borrowers or groups of related borrowers. In addition, repayment of such loans depends on the successful operation or management of the farm property securing the loan or for which an operating loan is utilized. Farming operations may be affected by adverse weather conditions such as drought, hail or floods that can severely limit crop yields. Consumer loans represent less than 1% of the outstanding total loan portfolio. Collateral consists primarily of automobiles and other personal assets. Credit score analysis is used to supplement the underwriting process. Most of the Company’s lending activity occurs within the State of Texas, primarily in the north, central and southeast Texas regions. A large percentage of the Company’s portfolio consists of commercial and residential real estate loans. As of March 31, 2017 and December 31, 2016 , there were no concentrations of loans related to a single industry in excess of 10% of total loans. The allowance for loan losses is an amount that management believes will be adequate to absorb estimated losses relating to specifically identified loans, as well as probable credit losses inherent in the balance of the loan portfolio. The allowance is derived from the following two components: 1) allowances established on individual impaired loans, which are based on a review of the individual characteristics of each loan, including the customer’s ability to repay the loan, the underlying collateral values, and the industry in which the customer operates, and 2) allowances based on actual historical loss experience for the last three years for similar types of loans in the Company’s loan portfolio adjusted for primarily changes in the lending policies and procedures; collection, charge-off and recovery practices; nature and volume of the loan portfolio; change in value of underlying collateral; volume and severity of nonperforming loans; existence and effect of any concentrations of credit and the level of such concentrations and current, national and local economic and business conditions. This second component also includes an unallocated allowance to cover uncertainties that could affect management’s estimate of probable losses. The unallocated allowance reflects the imprecision inherent in the underlying assumptions used in the methodologies for estimating this component. The Company’s management continually evaluates the allowance for loan losses determined from the allowances established on individual loans and the amounts determined from historical loss percentages adjusted for the qualitative factors above. Should any of the factors considered by management change, the Company’s estimate of loan losses could also change and would affect the level of future provision expense. While the calculation of the allowance for loan losses utilizes management’s best judgment and all the information available, the adequacy of the allowance for loan losses is dependent on a variety of factors beyond the Company’s control, including, among other things, the performance of the entire loan portfolio, the economy, changes in interest rates and the view of regulatory authorities towards loan classifications. In addition, regulatory agencies, as an integral part of their examination process, periodically review the Bank’s allowance for loan losses, and may require the Bank to make additions to the allowance based on their judgment about information available to them at the time of their examinations. Loans requiring an allocated loan loss provision are generally identified at the servicing officer level based on review of weekly past due reports and/or the loan officer’s communication with borrowers. In addition, past due loans are discussed at weekly officer loan committee meetings to determine if classification is warranted. The Company’s credit department has implemented an internal risk based loan review process to identity potential internally classified loans that supplements the annual independent external loan review. The external review generally covers all loans greater than $2.9 million annually. These reviews include analysis of borrower’s financial condition, payment histories and collateral values to determine if a loan should be internally classified. Generally, once classified, an impaired loan analysis is completed by the credit department to determine if the loan is impaired and the amount of allocated allowance required. The Texas economy, specifically the Company’s lending area of north, central and southeast Texas, has generally performed better than certain other parts of the country. The risk of loss associated with all segments of the portfolio could increase due to this impact. During the first quarter of 2016, the Company increased its reserves in the energy portfolio in response to the risk associated with volatility in oil prices. Due to the stabilization of commodity prices and reductions to the energy portfolio during the second half of 2016, the Company has not made any additional allocations during 2017 and believes economic factors indicate improvement in the energy sector and that the economy in our lending areas, including Houston, will continue to grow. The economy and other risk factors are minimized by the Company’s underwriting standards, which include the following principles: 1) financial strength of the borrower including strong earnings, high net worth, significant liquidity and acceptable debt to worth ratio, 2) managerial business competence, 3) ability to repay, 4) loan to value, 5) projected cash flow and 6) guarantor financial statements as applicable. The following is a summary of the activity in the allowance for loan losses by loan class for the three months ended March 31, 2017 and 2016 : Commercial Commercial Real Estate, Land and Land Development Residential Real Estate Single-Family Interim Construction Agricultural Consumer Other Unallocated Total Three months ended March 31, 2017 Balance at the beginning of period $ 8,593 $ 18,399 $ 2,760 $ 1,301 $ 207 $ 242 $ 29 $ 60 $ 31,591 Provision for loan losses (590 ) 2,048 67 235 (6 ) 64 23 182 2,023 Charge-offs — — — (134 ) — (56 ) (22 ) — (212 ) Recoveries 2 20 1 — — 2 4 — 29 Balance at end of period $ 8,005 $ 20,467 $ 2,828 $ 1,402 $ 201 $ 252 $ 34 $ 242 $ 33,431 Three months ended March 31, 2016 Balance at the beginning of period $ 10,573 $ 13,007 $ 2,339 $ 769 $ 215 $ 164 $ 8 $ (32 ) $ 27,043 Provision for loan losses 1,592 1,046 133 220 (28 ) (3 ) 22 15 2,997 Charge-offs — (54 ) — — — (1 ) (23 ) — (78 ) Recoveries 8 2 1 — — 2 9 — 22 Balance at end of period $ 12,173 $ 14,001 $ 2,473 $ 989 $ 187 $ 162 $ 16 $ (17 ) $ 29,984 The following table details the amount of the allowance for loan losses and recorded investment in loans by class as of March 31, 2017 and December 31, 2016: Commercial Commercial Real Estate, Land and Land Development Residential Real Estate Single-Family Interim Construction Agricultural Consumer Other Unallocated Total March 31, 2017 Allowance for losses: Individually evaluated for impairment $ 500 $ 4 $ — $ — $ — $ 94 $ — $ — $ 598 Collectively evaluated for impairment 7,505 20,463 2,828 1,402 201 158 34 242 32,833 Loans acquired with deteriorated credit quality — — — — — — — — — Ending balance $ 8,005 $ 20,467 $ 2,828 $ 1,402 $ 201 $ 252 $ 34 $ 242 $ 33,431 Loans: Individually evaluated for impairment $ 8,196 $ 2,843 $ 2,039 $ — $ — $ 264 $ — $ — $ 13,342 Collectively evaluated for impairment 591,823 3,103,643 643,455 237,740 52,515 25,951 112 — 4,655,239 Acquired with deteriorated credit quality 1,966 29,880 2,075 — — 9 — — 33,930 Ending balance $ 601,985 $ 3,136,366 $ 647,569 $ 237,740 $ 52,515 $ 26,224 $ 112 $ — $ 4,702,511 December 31, 2016 Allowance for losses: Individually evaluated for impairment $ 3 $ 4 $ — $ 84 $ — $ 94 $ — $ — $ 185 Collectively evaluated for impairment 8,590 18,395 2,760 1,217 207 148 29 60 31,406 Loans acquired with deteriorated credit quality — — — — — — — — — Ending balance $ 8,593 $ 18,399 $ 2,760 $ 1,301 $ 207 $ 242 $ 29 $ 60 $ 31,591 Loans: Individually evaluated for impairment $ 7,720 $ 7,089 $ 1,889 $ 884 $ — $ 279 $ — $ — $ 17,861 Collectively evaluated for impairment 620,665 2,953,333 630,689 234,591 53,548 27,240 166 — 4,520,232 Acquired with deteriorated credit quality 2,420 30,280 1,967 — — 11 — — 34,678 Ending balance $ 630,805 $ 2,990,702 $ 634,545 $ 235,475 $ 53,548 $ 27,530 $ 166 $ — $ 4,572,771 Nonperforming loans by loan class at March 31, 2017 and December 31, 2016, are summarized as follows: Commercial Commercial Real Estate, Land and Land Development Residential Real Estate Single-Family Interim Construction Agricultural Consumer Other Total March 31, 2017 Nonaccrual loans $ 8,196 $ 1,666 $ 1,031 $ — $ — $ 264 $ — $ 11,157 Loans past due 90 days and still accruing — — — — — — — — Troubled debt restructurings (not included in nonaccrual or loans past due and still accruing) — 1,177 1,008 — — — — 2,185 $ 8,196 $ 2,843 $ 2,039 $ — $ — $ 264 $ — $ 13,342 December 31, 2016 Nonaccrual loans $ 7,718 $ 5,885 $ 866 $ 884 $ — $ 273 $ — $ 15,626 Loans past due 90 days and still accruing — — — — — — — — Troubled debt restructurings (not included in nonaccrual or loans past due and still accruing) 1 1,204 1,011 — — — — 2,216 $ 7,719 $ 7,089 $ 1,877 $ 884 $ — $ 273 $ — $ 17,842 The accrual of interest is discontinued on a loan when management believes after considering collection efforts and other factors that the borrower's financial condition is such that collection of interest is doubtful. All interest accrued but not collected for loans that are placed on nonaccrual status or charged-off is reversed against interest income. Cash collections on nonaccrual loans are generally credited to the loan receivable balance, and no interest income is recognized on those loans until the principal balance has been collected. Loans are returned to accrual status when all the principal and interest amounts contractually due are brought current and future payments are reasonably assured. Impaired loans are those loans where it is probable that all amounts due will not be collected according to contractual terms of the loan agreement. The Company has identified these loans through its normal loan review procedures. Impaired loans are measured based on 1) the present value of expected future cash flows discounted at the loans effective interest rate; 2) the loan's observable market price; or 3) the fair value of collateral if the loan is collateral dependent. Substantially all of the Company’s impaired loans are measured at the fair value of the collateral. In limited cases, the Company may use the other methods to determine the level of impairment of a loan if such loan is not collateral dependent. All commercial, real estate, agricultural loans and troubled debt restructurings are considered for individual impairment analysis. Smaller balance consumer loans are collectively evaluated for impairment. Impaired loans by loan class at March 31, 2017 and December 31, 2016, are summarized as follows: Commercial Commercial Real Estate, Land and Land Development Residential Real Estate Single-Family Interim Construction Agricultural Consumer Other Total March 31, 2017 Recorded investment in impaired loans: Impaired loans with an allowance for loan losses $ 3,635 $ 77 $ — $ — $ — $ 204 $ — $ 3,916 Impaired loans with no allowance for loan losses 4,561 2,766 2,039 — — 60 — 9,426 Total $ 8,196 $ 2,843 $ 2,039 $ — $ — $ 264 $ — $ 13,342 Unpaid principal balance of impaired loans $ 11,319 $ 2,860 $ 2,249 $ — $ — $ 275 $ — $ 16,703 Allowance for loan losses on impaired loans $ 500 $ 4 $ — $ — $ — $ 94 $ — $ 598 December 31, 2016 Recorded investment in impaired loans: Impaired loans with an allowance for loan losses $ 8 $ 78 $ — $ 168 $ — $ 209 $ — $ 463 Impaired loans with no allowance for loan losses 7,712 7,011 1,889 716 — 70 — 17,398 Total $ 7,720 $ 7,089 $ 1,889 $ 884 $ — $ 279 $ — $ 17,861 Unpaid principal balance of impaired loans $ 10,844 $ 7,133 $ 2,087 $ 884 $ — $ 291 $ — $ 21,239 Allowance for loan losses on impaired loans $ 3 $ 4 $ — $ 84 $ — $ 94 $ — $ 185 For the three months ended March 31, 2017 Average recorded investment in impaired loans $ 7,958 $ 4,966 $ 1,964 $ 442 $ — $ 272 $ — $ 15,602 Interest income recognized on impaired loans $ 2 $ 397 $ 12 $ — $ — $ 1 $ — $ 412 For the three months ended March 31, 2016 Average recorded investment in impaired loans $ 15,677 $ 3,429 $ 3,157 $ — $ 85 $ 94 $ — $ 22,442 Interest income recognized on impaired loans $ 366 $ 36 $ 40 $ — $ — $ — $ — $ 442 Certain impaired loans have adequate collateral and do not require a related allowance for loan loss. The Company will charge off that portion of any loan which management considers a loss. Commercial and real estate loans are generally considered for charge-off when exposure beyond collateral coverage is apparent and when no further collection of the loss portion is anticipated based on the borrower’s financial condition. The restructuring of a loan is considered a “troubled debt restructuring” if both 1) the borrower is experiencing financial difficulties and 2) the creditor has granted a concession. Concessions may include interest rate reductions or below market interest rates, principal forgiveness, extending amortization and other actions intended to minimize potential losses. A “troubled debt restructured” loan is identified as impaired and measured for credit impairment as of each reporting period in accordance with the guidance in Accounting Standards Codification (ASC) 310-10-35. Modifications primarily relate to extending the amortization periods of the loans and interest rate concessions. The majority of these loans were identified as impaired prior to restructuring; therefore, the modifications did not materially impact the Company’s determination of the allowance for loan losses. The recorded investment in troubled debt restructurings, including those on nonaccrual, was $2,389 and $2,425 as of March 31, 2017 and December 31, 2016. There were no loans modified under troubled debt restructurings during the three months ended March 31, 2017 and 2016 . . At March 31, 2017 and 2016, there were no loans modified under troubled debt restructurings during the previous twelve month period that subsequently defaulted during the three months ended March 31, 2017 and 2016, respectively. At March 31, 2017 and 2016, the Company had no commitments to lend additional funds to any borrowers with loans whose terms have been modified under troubled debt restructurings. Loans are considered past due if the required principal and interest payments have not been received as of the date such payments were due. The following table presents information regarding the aging of past due loans by loan class as of March 31, 2017 and December 31, 2016: Loans 30-89 Days Past Due Loans 90 or More Past Due Total Past Due Loans Current Loans Total Loans March 31, 2017 Commercial $ 182 $ 8,196 $ 8,378 $ 593,607 $ 601,985 Commercial real estate, land and land development 1,631 1,631 3,262 3,133,104 3,136,366 Residential real estate 2,955 556 3,511 644,058 647,569 Single-family interim construction — — — 237,740 237,740 Agricultural — — — 52,515 52,515 Consumer 36 36 72 26,152 26,224 Other — — — 112 112 $ 4,804 $ 10,419 $ 15,223 $ 4,687,288 $ 4,702,511 December 31, 2016 Commercial $ 226 $ 7,711 $ 7,937 $ 622,868 $ 630,805 Commercial real estate, land and land development 151 6,752 6,903 2,983,799 2,990,702 Residential real estate 846 561 1,407 633,138 634,545 Single-family interim construction 1,062 — 1,062 234,413 235,475 Agricultural 10 — 10 53,538 53,548 Consumer 154 52 206 27,324 27,530 Other — — — 166 166 $ 2,449 $ 15,076 $ 17,525 $ 4,555,246 $ 4,572,771 The Company’s internal classified report is segregated into the following categories: 1) Pass/Watch, 2) Special Mention, 3) Substandard and 4) Doubtful. The loans placed in the Pass/Watch category reflect the Company’s opinion that the loans reflect potential weakness that requires monitoring on a more frequent basis. The loans in the Special Mention category reflect the Company’s opinion that the credit contains weaknesses which represent a greater degree of risk and warrant extra attention. These loans are reviewed monthly by officers and senior management to determine if a change in category is warranted. The loans placed in the Substandard category are considered to be potentially inadequately protected by the current debt service capacity of the borrower and/or the pledged collateral. These credits, even if apparently protected by collateral value, have shown weakness related to adverse financial, managerial, economic, market or political conditions, which may jeopardize repayment of principal and interest. There is possibility that some future loss could be sustained by the Company if such weakness is not corrected. The Doubtful category includes loans that are in default or principal exposure is probable. Substandard and Doubtful loans are individually evaluated to determine if they should be classified as impaired and an allowance is allocated if deemed necessary under ASC 310-10. The loans that are not impaired are included with the remaining “pass” credits in determining the portion of the allowance for loan loss based on historical loss experience and other qualitative factors. The portfolio is segmented into categories including: commercial loans, consumer loans, commercial real estate loans, residential real estate loans and agricultural loans. The adjusted historical loss percentage is applied to each category. Each category is then added together to determine the allowance allocated under ASC 450-20. A summary of loans by credit quality indicator by class as of March 31, 2017 and December 31, 2016 , is as follows: Pass Pass/ Watch Special Mention Substandard Doubtful Total March 31, 2017 Commercial $ 525,014 $ 34,378 $ 15,563 $ 27,030 $ — $ 601,985 Commercial real estate, construction, land and land development 3,122,652 5,699 4,942 3,073 — 3,136,366 Residential real estate 640,467 3,292 490 3,320 — 647,569 Single-family interim construction 236,803 937 — — — 237,740 Agricultural 39,190 13,100 225 — — 52,515 Consumer 25,931 17 2 274 — 26,224 Other 112 — — — — 112 $ 4,590,169 $ 57,423 $ 21,222 $ 33,697 $ — $ 4,702,511 December 31, 2016 Commercial $ 555,342 $ 31,954 $ 16,734 $ 26,775 $ — $ 630,805 Commercial real estate, construction, land and land development 2,972,732 5,426 5,148 7,396 — 2,990,702 Residential real estate 629,081 1,897 370 3,197 — 634,545 Single-family interim construction 233,800 791 — 884 — 235,475 Agricultural 52,724 569 255 — — 53,548 Consumer 27,215 12 3 300 — 27,530 Other 166 — — — — 166 $ 4,471,060 $ 40,649 $ 22,510 $ 38,552 $ — $ 4,572,771 The Company has acquired certain loans which experienced credit deterioration since origination (purchased credit impaired (PCI) loans). Accretion on PCI loans is based on estimated future cash flows, regardless of contractual maturity. No additional PCI loans were acquired during the three months ended March 31, 2017 and the year ended December 31, 2016. The carrying amount of all acquired PCI loans included in the consolidated balance sheet and the related outstanding balance at March 31, 2017 and December 31, 2016 were as follows: March 31, 2017 December 31, 2016 Outstanding balance $ 38,380 $ 39,442 Carrying amount 33,930 34,678 There was no allocation established in the allowance for loan losses relating to PCI loans at March 31, 2017 or December 31, 2016. The changes in accretable yield during the three months ended March 31, 2017 and 2016 in regard to loans transferred at acquisition for which it was probable that all contractually required payments would not be collected are presented in the table below. For the Three Months Ended March 31, 2017 2016 Balance at January 1, $ 1,526 $ 2,380 Additions — — Accretion (225 ) (302 ) Transfers from nonaccretable 270 — Balance at March 31, $ 1,571 $ 2,078

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Financial Instruments with Off-Balance Sheet Risk The Company is a party to financial instruments with off-balance sheet risk in the normal course of business to meet the financing needs of its customers. The commitments involve, to varying degrees, elements of credit and interest rate risk in excess of the amount recognized in the balance sheet. The Company’s exposure to credit loss in the event of nonperformance by the other party to the financial instrument for commitments to extend credit is represented by the contractual amount of this instrument. The Company uses the same credit policies in making commitments and conditional obligations as it does for on-balance sheet instruments. At March 31, 2017 and December 31, 2016 , the approximate amounts of these financial instruments were as follows: March 31, December 31, 2017 2016 Commitments to extend credit $ 873,962 $ 865,668 Standby letters of credit 7,623 10,562 $ 881,585 $ 876,230 Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. Since many of the commitments are expected to expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. The Company evaluates each customer’s credit worthiness on a case-by-case basis. The amount of collateral obtained if deemed necessary by the Company upon extension of credit is based on management’s credit evaluation of the counterparty. Collateral held varies but may include accounts receivable, inventory, farm crops, property, plant and equipment and income-producing commercial properties. Letters of credit are written conditional commitments used by the Company to guarantee the performance of a customer to a third party. The Company’s policies generally require that letter of credit arrangements contain security and debt covenants similar to those contained in loan arrangements. In the event the customer does not perform in accordance with the terms of the agreement with the third party, the Company would be required to fund the commitment. The maximum potential amount of future payments the Company could be required to make is represented by the contractual amount shown in the table above. If the commitment is funded, the Company would be entitled to seek recovery from the customer. As of March 31, 2017 and December 31, 2016 , no amounts have been recorded as liabilities for the Company’s potential obligations under these guarantees. Litigation The Company is involved in certain legal actions arising from normal business activities. Management believes that the outcome of such proceedings will not materially affect the financial position, results of operations or cash flows of the Company. Independent Bank is a party to a legal proceeding inherited in connection with its acquisition of BOH Holdings, Inc. and its subsidiary, Bank of Houston. Please see Part II, Item 1. for more details on this lawsuit. Lease Commitments The Company leases certain branch facilities and other facilities. Rent expense related to these leases amounted to $ 681 and $ 675 for the three months ended March 31, 2017 and 2016, respectively.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income tax expense for the three months ended March 31, 2017 and 2016 was as follows: Three Months Ended March 31, 2017 2016 Income tax expense for the period $ 6,728 $ 6,162 Effective tax rate 30.0 % 33.1 % The effective tax rates differ from the statutory federal tax rate of 35% largely due to tax exempt interest income earned on certain investment securities and loans and the nontaxable earnings on bank owned life insurance. In addition, the effective tax rate differs for the period ended March 31, 2017 due to the excess tax benefit on restricted stock, which was recognized in income tax expense as a result of adopting ASU 2016-09, which became effective for the Company on January 1, 2017.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The fair value of an asset or liability is the price that would be received to sell that asset or paid to transfer that liability in an orderly transaction occurring in the principal market (or most advantageous market in the absence of a principal market) for such asset or liability. In estimating fair value, the Company utilizes valuation techniques that are consistent with the market approach, the income approach and/or the cost approach. Such valuation techniques are consistently applied. Inputs to valuation techniques include the assumptions that market participants would use in pricing an asset or liability. ASC Topic 820, Fair Value Measurements and Disclosures , establishes a fair value hierarchy for valuation inputs that gives the highest priority to quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. The fair value hierarchy is as follows: Level 1 Inputs – Unadjusted quoted prices in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. Level 2 Inputs – Inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. These might include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (such as interest rates, volatilities, prepayment speeds, credit risks, etc.) or inputs that are derived principally from or corroborated by market data by correlation or other means. Level 3 Inputs – Unobservable inputs for determining the fair values of assets or liabilities that reflect an entity’s own assumptions about the assumptions that market participants would use in pricing the assets or liabilities. The following table represents assets reported on the consolidated balance sheets at their fair value on a recurring basis as of March 31, 2017 and December 31, 2016 by level within the ASC Topic 820 fair value measurement hierarchy: Fair Value Measurements at Reporting Date Using Assets/ Liabilities Measured at Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) March 31, 2017 Measured on a recurring basis: Assets: Investment securities available for sale: U.S. treasuries $ 3,158 $ — $ 3,158 $ — Government agency securities 135,708 — 135,708 — Obligations of state and municipal subdivisions 103,366 — 103,366 — Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC 108,177 — 108,177 — December 31, 2016 Measured on a recurring basis: Assets: Investment securities available for sale: U.S. treasuries $ 3,147 $ — $ 3,147 $ — Government agency securities 122,267 — 122,267 — Obligations of state and municipal subdivisions 87,256 — 87,256 — Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC 103,765 — 103,765 — There were no transfers between level categorizations and no changes in valuation methodologies for the periods presented. A description of the valuation methodologies used for instruments measured at fair value, as well as the general classification of such instruments pursuant to the valuation hierarchy, is set forth below. Securities classified as available for sale are reported at fair value utilizing Level 2 inputs. For these securities, the Company obtains fair value measurements from an independent pricing service. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury and other yield curves, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the security’s terms and conditions, among other things. In accordance with ASC Topic 820, certain assets and liabilities are measured at fair value on a nonrecurring basis; that is, the assets and liabilities are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (for example, when there is evidence of impairment). The following table presents the assets carried on the consolidated balance sheet by caption and by level in the fair value hierarchy at March 31, 2017 and December 31, 2016, for which a nonrecurring change in fair value has been recorded: Fair Value Measurements at Reporting Date Using Assets Measured at Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Period Ended Total Losses March 31, 2017 Measured on a nonrecurring basis: Assets: Impaired loans $ 3,135 $ — $ — $ 3,135 $ 500 Other real estate — — — — — December 31, 2016 Measured on a nonrecurring basis: Assets: Impaired loans $ 968 $ — $ — $ 968 $ 708 Other real estate 340 — — 340 52 Impaired loans (loans which are not expected to repay all principal and interest amounts due in accordance with the original contractual terms) are measured at an observable market price (if available) or at the fair value of the loan’s collateral (if collateral dependent). Fair value of the loan’s collateral is determined by appraisals or independent valuation, which is then adjusted for the estimated costs related to liquidation of the collateral. Management’s ongoing review of appraisal information may result in additional discounts or adjustments to valuation based upon more recent market sales activity or more current appraisal information derived from properties of similar type and/or locale. Therefore, the Company has categorized its impaired loans as Level 3. Other real estate is measured at fair value on a nonrecurring basis (upon initial recognition or subsequent impairment). Other real estate is classified within Level 3 of the valuation hierarchy. When transferred from the loan portfolio, other real estate is adjusted to fair value less estimated selling costs and is subsequently carried at the lower of carrying value or fair value less estimated selling costs. The fair value is determined using an external appraisal process, discounted based on internal criteria. In addition, mortgage loans held for sale are required to be measured at the lower of cost or fair value. The fair value of mortgage loans held for sale is based upon binding quotes or bids from third party investors. As of March 31, 2017 and December 31, 2016, all mortgage loans held for sale were recorded at cost. The methods and assumptions used by the Company in estimating fair values of financial instruments as disclosed herein in accordance with ASC Topic 825, Financial Instruments , other than for those measured at fair value on a recurring and nonrecurring basis discussed above, are as follows: Cash and cash equivalents: The carrying amounts of cash and cash equivalents approximate their fair value. Certificates of deposit held in other banks: The fair value of certificates of deposit held in other banks is based upon current rates in the market. Loans and loans held for sale: For variable-rate loans that reprice frequently and have no significant changes in credit risk, fair values are based on carrying values. Fair values for certain mortgage loans (for example, one-to-four family residential), commercial real estate and commercial loans are estimated using discounted cash flow analyses, using interest rates currently being offered for loans with similar terms to borrowers of similar credit quality. Federal Home Loan Bank of Dallas and other restricted stock: The carrying value of restricted securities such as stock in the Federal Home Loan Bank of Dallas and Independent Bankers Financial Corporation approximates fair value. Deposits: The fair values disclosed for demand deposits are, by definition, equal to the amount payable on demand at the reporting date (that is their carrying amounts). The carrying amounts of variable-rate certificates of deposit (CDs) approximate their fair values at the reporting date. Fair values for fixed-rate CDs are estimated using a discounted cash flow calculation that applies interest rates currently being offered on certificates to a schedule of aggregated expected monthly maturities on time deposits. Federal Home Loan Bank advances, line of credit and federal funds purchased: The fair value of advances maturing within 90 days approximates carrying value. Fair value of other advances is based on the Company’s current borrowing rate for similar arrangements. Other borrowings: The fair value of private subordinated debentures are based upon prevailing rates on similar debt in the market place. The subordinated debentures that are publicly traded are valued based on indicative bid prices based upon market pricing observations in the current market. Junior subordinated debentures: The fair value of junior subordinated debentures is estimated using discounted cash flow analyses based on the Company’s current incremental borrowing rates for similar types of borrowing arrangements. Accrued interest: The carrying amounts of accrued interest approximate their fair values. Off-balance sheet instruments: Fair values for off-balance sheet, credit-related financial instruments are based on fees currently charged to enter into similar agreements, taking into account the remaining terms of the agreements and the counterparties' credit standing. The fair value of commitments is not material. The carrying amount, estimated fair value and the level of the fair value hierarchy of the Company’s financial instruments were as follows at March 31, 2017 and December 31, 2016: Fair Value Measurements at Reporting Date Using Carrying Amount Estimated Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) March 31, 2017 Financial assets: Cash and cash equivalents $ 515,123 $ 515,123 $ 515,123 $ — $ — Certificates of deposit held in other banks 5,892 5,943 — 5,943 — Securities available for sale 350,409 350,409 — 350,409 — Loans held for sale 5,081 5,081 — 5,081 — Loans, net 4,666,653 4,636,219 — 4,632,901 3,318 FHLB of Dallas stock and other restricted stock 26,672 26,672 — 26,672 — Accrued interest receivable 11,410 11,410 — 11,410 — Financial liabilities: Deposits 4,722,203 4,726,879 — 4,726,879 — Accrued interest payable 2,398 2,398 — 2,398 — FHLB advances 460,727 469,430 — 469,430 — Other borrowings 107,388 110,550 — 110,550 — Junior subordinated debentures 18,147 18,140 — 18,140 — Off-balance sheet assets (liabilities): Commitments to extend credit — — — — — Standby letters of credit — — — — — December 31, 2016 Financial assets: Cash and cash equivalents $ 505,027 $ 505,027 $ 505,027 $ — $ — Certificates of deposit held in other banks 2,707 2,733 — 2,733 — Securities available for sale 316,435 316,435 — 316,435 — Loans held for sale 9,795 9,795 — 9,795 — Loans, net 4,539,063 4,532,364 — 4,532,086 278 FHLB of Dallas stock and other restricted stock 26,536 26,536 — 26,536 — Accrued interest receivable 12,331 12,331 — 12,331 — Financial liabilities: Deposits 4,577,109 4,581,866 — 4,581,866 — Accrued interest payable 4,020 4,020 — 4,020 — FHLB advances 460,746 459,436 — 459,436 — Other borrowings 107,299 110,000 — 110,000 — Junior subordinated debentures 18,147 18,131 — 18,131 — Off-balance sheet assets (liabilities): Commitments to extend credit — — — — — Standby letters of credit — — — — —

Stock Awards and Stock Warrants

Stock Awards and Stock Warrants	3 Months Ended
	Mar. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Awards and Stock Warrants	Stock Awards and Stock Warrants The Company grants common stock awards to certain employees of the Company. The common stock issued prior to 2013 vests five years from the date the award is granted and the related compensation expense is recognized over the vesting period. In connection with the initial public offering in April 2013, the Board of Directors adopted a new 2013 Equity Incentive Plan. Under this plan, the Compensation Committee may grant awards in the form of restricted stock, restricted stock rights, restricted stock units, qualified and nonqualified stock options, performance-based share awards and other equity-based awards. The Plan reserved 800,000 shares of common stock to be awarded by the Company’s compensation committee. The shares currently issued under the 2013 Plan are restricted and will vest evenly over the required employment period, generally ranging from three to five years. Shares granted under a previous plan prior to 2012 and those in and subsequent to 2013 under the 2013 Equity Incentive Plan were issued at the date of grant and receive dividends. Shares issued under a revised plan in 2012 are not outstanding shares of the Company until they vest and do not receive dividends. During the three months ended March 31, 2017, 11,040 shares that were issued under the 2012 Plan vested during the period. The following table summarizes the activity in nonvested shares for the three months ended March 31, 2017 and 2016 : Number of Shares Weighted Average Grant Date Fair Value Nonvested shares, December 31, 2016 280,524 $ 36.88 Granted during the period 40,627 62.37 Vested during the period (65,668 ) 31.23 Forfeited during the period — — Nonvested shares, March 31, 2017 255,483 $ 42.38 Nonvested shares, December 31, 2015 373,572 $ 40.29 Granted during the period 66,220 29.91 Vested during the period (44,220 ) 32.61 Forfeited during the period (6,334 ) 42.25 Nonvested shares, March 31, 2016 389,238 $ 39.20 Compensation expense related to these awards is recorded based on the fair value of the award at the date of grant and totaled $970 and $1,220 for the three months ended March 31, 2017 and 2016, respectively. Compensation expense is recorded in salaries and employee benefits in the accompanying consolidated statements of income. At March 31, 2017 , future compensation expense is estimated to be $8,015 and will be recognized over a remaining weighted average period of 2.76 years. The fair value of common stock awards that vested during the three months ended March 31, 2017 and 2016 was $4,119 and $1,306 , respectively. The Company has recorded $ 724 in excess tax benefits on vested restricted stock to income tax expense for the three months ended March 31, 2017 as a result of adopting ASU 2016-09. The Company recorded $ (83) to additional paid in capital, which represents the income tax deficiency recognized on the vested shares for the three months ended March 31, 2016. At March 31, 2017 , the future vesting schedule of the nonvested shares is as follows: First year 124,575 Second year 79,482 Third year 41,526 Fourth year 6,050 Fifth year 3,850 Total nonvested shares 255,483 The Company has warrants outstanding representing the right to purchase 147,341 shares of Company stock at $17.19 per share to certain Company directors and shareholders. The warrants were issued in return for the shareholders' agreement to repurchase the subordinated debt outstanding to an unaffiliated bank in the event of Company default. The warrants were recorded as equity awards at fair value and were being amortized over the term of the debt. The subordinated debt was paid off by the Company in 2013. The warrants expire in December 2018. During the three months ended March 31, 2017, warrants to purchase 3,203 shares of common stock were exercised and have been issued by the Company.

Regulatory Matters

Regulatory Matters	3 Months Ended
	Mar. 31, 2017
Regulated Operations [Abstract]
Regulatory Matters	Regulatory Matters Under banking law, there are legal restrictions limiting the amount of dividends the Bank can declare. Approval of the regulatory authorities is required if the effect of dividends declared would cause the regulatory capital of the Bank to fall below specified minimum levels. For state banks, subject to regulatory capital requirements, payment of dividends is generally allowed to the extent of net profits. The Company (on a consolidated basis) and the Bank are subject to various regulatory capital requirements administered by federal and state 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 effect on the Company’s consolidated 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 assets, liabilities and certain off-balance sheet items as calculated under regulatory accounting practices. The capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weightings and other factors. The Company is subject to the Basel III regulatory capital framework (the "Basel III Capital Rules"). Starting in January 2016, the implementation of the capital conservation buffer was effective for the Company starting at the 0.625% level and increasing 0.625% each year thereafter, until it reaches 2.5% on January 1, 2019. The capital conservation buffer is designed to absorb losses during periods of economic stress and requires increased capital levels for the purpose of capital distributions and other payments. Failure to meet the full amount of the buffer will result in restrictions on the Company's ability to make capital distributions, including dividend payments and stock repurchases and to pay discretionary bonuses to executive officers. Quantitative measures established by regulation to ensure capital adequacy require the Company and the Bank to maintain minimum amounts and ratios (set forth in the table below) of total, CET1 and Tier 1 capital (as defined in the regulations) to risk weighted assets (as defined), and of Tier 1 capital (as defined) to average assets (as defined). Management believes, as of March 31, 2017 and December 31, 2016, the Company and the Bank meet all capital adequacy requirements to which they are subject, including the capital buffer requirement. As of March 31, 2017 and December 31, 2016, the Bank’s capital ratios exceeded those levels necessary to be categorized as “well capitalized” under the regulatory framework for prompt corrective action. To be categorized as “well capitalized," the Bank must maintain minimum total risk based, CET1, Tier 1 risk based and Tier 1 leverage ratios as set forth in the table. There are no conditions or events since that notification that management believes have changed the Bank’s category. The actual capital amounts and ratios of the Company and Bank as of March 31, 2017 and December 31, 2016, are presented in the following table: Actual Minimum for Capital Adequacy Purposes To Be Well Capitalized Under Prompt Corrective Action Provisions Amount Ratio Amount Ratio Amount Ratio March 31, 2017 Total capital to risk weighted assets: Consolidated $ 583,864 11.44 % $ 408,474 8.00 % N/A N/A Bank 572,757 11.22 408,247 8.00 $ 510,309 10.00 % Tier 1 capital to risk weighted assets: Consolidated 440,433 8.63 306,356 6.00 N/A N/A Bank 539,326 10.57 306,185 6.00 408,247 8.00 Common equity tier 1 to risk weighted assets Consolidated 422,833 8.28 229,767 4.50 N/A N/A Bank 539,326 10.57 229,639 4.50 331,701 6.50 Tier 1 capital to average assets: Consolidated 440,433 7.84 224,601 4.00 N/A N/A Bank 539,326 9.61 224,491 4.00 280,614 5.00 December 31, 2016 Total capital to risk weighted assets: Consolidated $ 568,808 11.38 % $ 399,698 8.00 % N/A N/A Bank 558,551 11.19 399,497 8.00 $ 499,371 10.00 % Tier 1 capital to risk weighted assets: Consolidated 427,217 8.55 299,774 6.00 N/A N/A Bank 526,960 10.55 299,623 6.00 399,497 8.00 Common equity tier 1 to risk weighted assets Consolidated 409,617 8.20 224,830 4.50 N/A N/A Bank 526,960 10.55 224,717 4.50 324,591 6.50 Tier 1 capital to average assets: Consolidated 427,217 7.82 218,612 4.00 N/A N/A Bank 526,960 9.65 218,517 4.00 273,146 5.00

Subsequent Event

Subsequent Event	3 Months Ended
	Mar. 31, 2017
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event Carlile Bancshares, Inc. On April 1, 2017, the Company acquired 100% of the outstanding stock of Carlile Bancshares, Inc. ("CBI"). and its subsidiary, Northstar Bank, Denton, Texas. This transaction gives the Company 24 branches in the DFW Metroplex and Austin area as well as 18 branches in Colorado. The Company issued 8,804,699 shares of Company stock and paid $17,463 in cash for the outstanding shares of CBI common stock. The Company has recognized a provisional amount of goodwill of $362,922 which is calculated as the excess of both the consideration exchanged and liabilities assumed compared to the fair market value of identifiable assets acquired. The goodwill in this acquisition resulted from a combination of expected synergies and entrance into desirable Texas and Colorado markets. None of the goodwill recognized is expected to be deductible for income tax purposes. The Company has incurred expenses related to the acquisition of approximately $146 for the three months ended March 31, 2017, which is included in acquisition expenses in the consolidated statements of income. The Company incurred expenses of $ 659 during the year ended December 31, 2016. Provisional estimates for loans, premises and equipment, goodwill, core deposit intangible and deposits have been recorded for the acquisition as final valuations are not yet available. The Company does not expect any significant differences from estimated values upon completion of the valuations. The Company is still evaluating the loan portfolio for credit-impaired and non-credit-impaired loan estimations, therefore, the amounts are not available for disclosure. Estimated fair values of the assets acquired and liabilities assumed in this transaction as of the closing date are as follows: Assets of acquired bank: Cash and cash equivalents $ 159,469 Securities available for sale 336,506 Loans 1,396,169 Premises and equipment 63,581 Other real estate owned 10,666 Goodwill 362,922 Core deposit intangible 15,623 Other assets 92,696 Total assets acquired $ 2,437,632 Liabilities of acquired bank: Deposits $ 1,834,655 Junior subordinated debentures 12,566 Other liabilities 20,893 Total liabilities assumed $ 1,868,114 Common stock issued at $62.70 per share $ 552,055 Cash paid $ 17,463 To determine pro forma information, the Company adjusted its 2017 and 2016 historical results to include the historical results for CBI for the three months ended March 31, 2017 and 2016 and the year ended December 31, 2016. Pro forma net income for the three months ended March 31, 2017 and 2016 was $23,763 and $17,985 , respectively, and pro forma revenue was $88,564 and $84,853 , respectively, had the transaction occurred as of January 1, 2016. Pro forma net income for the year ended December 31, 2016 was $69,391 and pro forma revenue was $350,067 had the transaction occurred on January 1, 2016. Nonrecurring adjustments directly attributable to the acquisition included in the pro forma revenues and net income were expenses related to professional fees, integration costs, as well as change of control and noncompete agreements. For the three months ended March 31, 2017 and 2016 and the year ended December 31, 2016, these expenses totaled $16,339 , $0 , and $659 , respectively. Declaration of Dividends On April 26, 2017, the Company declared a quarterly cash dividend in the amount of $0.10 per share of common stock to the stockholders of record on May 8, 2017. The dividend will be paid on May 18, 2017.

Summary of Significant Accoun19

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation: The accompanying consolidated financial statements include the accounts of IBG, its wholly-owned subsidiaries, the Bank and IBG Adriatica Holdings, Inc. (Adriatica) and the Bank’s wholly-owned subsidiaries, IBG Real Estate Holdings, Inc., IBG Aircraft Company III, Preston Grand, Inc, and McKinney Avenue Holdings, Inc. and its wholly owned subsidiary, McKinney Avenue SPE 1, Inc. Adriatica, McKinney Avenue Holdings, Inc. and its subsidiary are currently not active entities. All material intercompany transactions and balances have been eliminated in consolidation. In addition, the Company wholly-owns IB Trust I (Trust I), IB Trust II (Trust II), IB Trust III (Trust III), IB Centex Trust I (Centex Trust I) and Community Group Statutory Trust I (CGI Trust I). The Trusts were formed to issue trust preferred securities and do not meet the criteria for consolidation. The consolidated interim financial statements are unaudited, but include all adjustments, which, in the opinion of management, are necessary for a fair presentation of the results of the periods presented. All such adjustments were of a normal and recurring nature. These financial statements should be read in conjunction with the financial statements and the notes thereto in the Company's Annual Report of Form10-K for the year ended December 31, 2016. The consolidated statement of condition at December 31, 2016 had been derived from the audited financial statements as of that date, but does not include all of the information and footnotes required by accounting principles generally accepted in the United States of America for complete financial statements.
Segment Reporting	Segment Reporting: The Company has one reportable segment. The Company’s chief operating decision-maker uses consolidated results to make operating and strategic decisions.
Reclassifications	Reclassifications: Certain prior period financial statement amounts have been reclassified to conform to current period presentation. The reclassifications have no effect on net income or stockholders' equity as previously reported.
New Accounting Pronouncement	New Accounting Pronouncement: ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting was effective for the Company on January 1, 2017. ASU 2016-09 requires that all income tax effects related to vestings of share-based payment awards be reported in earnings as an increase (or decrease) to income tax expense. Previously, excess income tax benefits of a vested award were reported as an increase (or decrease) to additional paid-in capital to the extent that those benefits were greater than (or less than) the income tax benefits recognized in earnings during the award's vesting period. The requirement to report those income tax effects in earnings has been applied to vestings occurring on or after January 1, 2017 and resulted in recording a $724 thousand tax benefit for the period ended March 31, 2017. ASU 2016-09 also requires that all income tax-related cash flows resulting from share-based payments be reported as operating activities in the statement of cash flows. We have elected to apply that change in cash flow classification on a prospective basis. The impact of this change and that of the remaining provisions of ASU 2016-09 did not have significant impact on our financial statements.
Subsequent Events	Subsequent events: Companies are required to evaluate events and transactions that occur after the balance sheet date but before the date the financial statements are issued. They must recognize in the financial statements the effect of all events or transactions that provide additional evidence of conditions that existed at the balance sheet date, including the estimates inherent in the financial statement preparation process. Entities shall not recognize the impact of events or transactions that provide evidence about conditions that did not exist at the balance sheet date but arose after that date. The Company has evaluated subsequent events through the date of filing these financial statements with the Securities and Exchange Commission (SEC) and noted no subsequent events requiring financial statement recognition or disclosure, except as disclosed in Note 10.
Earnings Per Share	Earnings per share: Basic earnings per common share are net income available to common shareholders divided by the weighted average number of common shares outstanding during the period. The unvested share-based payment awards that contain rights to non forfeitable dividends are considered participating securities for this calculation. Diluted earnings per common share include the dilutive effect of additional potential common shares issuable under stock warrants. The participating nonvested common stock was not included in dilutive shares as it was anti-dilutive for the three months ended March 31, 2017. Proceeds from the assumed exercise of dilutive stock warrants are assumed to be used to repurchase common stock at the average market price.
Allowance for Loan Losses	The allowance is derived from the following two components: 1) allowances established on individual impaired loans, which are based on a review of the individual characteristics of each loan, including the customer’s ability to repay the loan, the underlying collateral values, and the industry in which the customer operates, and 2) allowances based on actual historical loss experience for the last three years for similar types of loans in the Company’s loan portfolio adjusted for primarily changes in the lending policies and procedures; collection, charge-off and recovery practices; nature and volume of the loan portfolio; change in value of underlying collateral; volume and severity of nonperforming loans; existence and effect of any concentrations of credit and the level of such concentrations and current, national and local economic and business conditions. This second component also includes an unallocated allowance to cover uncertainties that could affect management’s estimate of probable losses. The unallocated allowance reflects the imprecision inherent in the underlying assumptions used in the methodologies for estimating this component. The Company’s management continually evaluates the allowance for loan losses determined from the allowances established on individual loans and the amounts determined from historical loss percentages adjusted for the qualitative factors above. Should any of the factors considered by management change, the Company’s estimate of loan losses could also change and would affect the level of future provision expense. While the calculation of the allowance for loan losses utilizes management’s best judgment and all the information available, the adequacy of the allowance for loan losses is dependent on a variety of factors beyond the Company’s control, including, among other things, the performance of the entire loan portfolio, the economy, changes in interest rates and the view of regulatory authorities towards loan classifications.
Nonaccrual Loan and Lease Status	The accrual of interest is discontinued on a loan when management believes after considering collection efforts and other factors that the borrower's financial condition is such that collection of interest is doubtful. All interest accrued but not collected for loans that are placed on nonaccrual status or charged-off is reversed against interest income. Cash collections on nonaccrual loans are generally credited to the loan receivable balance, and no interest income is recognized on those loans until the principal balance has been collected. Loans are returned to accrual status when all the principal and interest amounts contractually due are brought current and future payments are reasonably assured.
Impaired Loan and Lease Receivable	Impaired loans are those loans where it is probable that all amounts due will not be collected according to contractual terms of the loan agreement. The Company has identified these loans through its normal loan review procedures. Impaired loans are measured based on 1) the present value of expected future cash flows discounted at the loans effective interest rate; 2) the loan's observable market price; or 3) the fair value of collateral if the loan is collateral dependent. Substantially all of the Company’s impaired loans are measured at the fair value of the collateral. In limited cases, the Company may use the other methods to determine the level of impairment of a loan if such loan is not collateral dependent.
Loan Charge off Amounts	The Company will charge off that portion of any loan which management considers a loss. Commercial and real estate loans are generally considered for charge-off when exposure beyond collateral coverage is apparent and when no further collection of the loss portion is anticipated based on the borrower’s financial condition.
Troubled Debt Restructuring	The restructuring of a loan is considered a “troubled debt restructuring” if both 1) the borrower is experiencing financial difficulties and 2) the creditor has granted a concession. Concessions may include interest rate reductions or below market interest rates, principal forgiveness, extending amortization and other actions intended to minimize potential losses. A “troubled debt restructured” loan is identified as impaired and measured for credit impairment as of each reporting period in accordance with the guidance in Accounting Standards Codification (ASC) 310-10-35.

Summary of Significant Accoun20

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Earning Per Share	The following table presents a reconciliation of net income available to common shareholders and the number of shares used in the calculation of basic and diluted earnings per common share. Three Months Ended March 31, 2017 2016 Basic earnings per share: Net income $ 15,671 $ 12,452 Less: Preferred stock dividends — (8 ) Net income after preferred stock dividends 15,671 12,444 Less: Undistributed earnings allocated to participating securities 176 211 Dividends paid on participating securities 24 28 Net income available to common shareholders $ 15,471 $ 12,205 Weighted-average basic shares outstanding 18,667,274 18,089,853 Basic earnings per share $ 0.83 $ 0.67 Diluted earnings per share: Net income available to common shareholders $ 15,471 $ 12,205 Total weighted-average basic shares outstanding 18,667,274 18,089,853 Add dilutive stock warrants 107,132 61,492 Add dilutive participating securities — 22,255 Total weighted-average diluted shares outstanding 18,774,406 18,173,600 Diluted earnings per share $ 0.82 $ 0.67 Anti-dilutive participating securities 126,847 —

Statement of Cash Flows (Tables

Statement of Cash Flows (Tables)	3 Months Ended
	Mar. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Other Supplemental Cash Flow Information	Other supplemental cash flow information is presented below: Three Months Ended March 31, 2017 2016 Cash transactions: Interest expense paid $ 9,694 $ 6,823 Income taxes paid $ — $ 760 Noncash transactions: Transfers of loans to other real estate owned $ 750 $ — Securities purchased, not yet settled $ 6,068 $ — Excess tax deficiency on restricted stock vested $ — $ (83 ) Transfer of repurchase agreements to deposits $ — $ 20,688 The supplemental schedule of noncash investing activities from Company acquisition activity includes the following measurement-period adjustments made during the period: Three Months Ended March 31, 2017 2016 Assets acquired: Loans $ — $ 735 Goodwill — (324 ) Core deposit intangibles — (216 ) Deferred tax asset — (175 ) Total assets $ — $ 20 Liabilities assumed: Other liabilities — 20 Total liabilities $ — $ 20

Securities Available for Sale (

Securities Available for Sale (Tables)	3 Months Ended
	Mar. 31, 2017
Available-for-sale Securities [Abstract]
Amortized Cost of Securities and Approximate Fair Values	The amortized cost of securities and their approximate fair values at March 31, 2017 and December 31, 2016, are as follows: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Securities Available for Sale March 31, 2017 U. S. treasuries $ 3,196 $ — $ (38 ) $ 3,158 Government agency securities 136,621 165 (1,078 ) 135,708 Obligations of state and municipal subdivisions 103,554 1,259 (1,447 ) 103,366 Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC 107,643 1,085 (551 ) 108,177 $ 351,014 $ 2,509 $ (3,114 ) $ 350,409 December 31, 2016 U.S. treasuries $ 3,208 $ — $ (61 ) $ 3,147 Government agency securities 123,605 141 (1,479 ) 122,267 Obligations of state and municipal subdivisions 88,358 920 (2,022 ) 87,256 Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC 103,869 928 (1,032 ) 103,765 $ 319,040 $ 1,989 $ (4,594 ) $ 316,435
Amortized Cost and Estimated Fair Value of Securities Available for Sale by Contractual Maturity	The amortized cost and estimated fair value of securities available for sale at March 31, 2017 , by contractual maturity, are shown below. Maturities of pass-through certificates will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. March 31, 2017 Securities Available for Sale Amortized Cost Fair Value Due in one year or less $ 31,149 $ 31,132 Due from one year to five years 113,221 112,685 Due from five to ten years 37,014 36,601 Thereafter 61,987 61,814 243,371 242,232 Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC 107,643 108,177 $ 351,014 $ 350,409
Summary of Unrealized Losses and Fair Value Securities in Continuous Unrealized Loss Position	The number of securities, unrealized losses and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, as of March 31, 2017 and December 31, 2016, are summarized as follows: Less Than 12 Months Greater Than 12 Months Total Description of Securities Number of Securities Estimated Fair Value Unrealized Losses Number of Securities Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses Securities Available for Sale March 31, 2017 U.S. treasuries 1 $ 3,158 $ (38 ) — $ — $ — $ 3,158 $ (38 ) Government agency securities 45 104,389 (1,072 ) 1 995 (6 ) 105,384 (1,078 ) Obligations of state and municipal subdivisions 76 38,076 (1,418 ) 5 2,185 (29 ) 40,261 (1,447 ) Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC 28 70,714 (551 ) — — — 70,714 (551 ) 150 $ 216,337 $ (3,079 ) 6 $ 3,180 $ (35 ) $ 219,517 $ (3,114 ) December 31, 2016 U.S. treasuries 1 $ 3,147 $ (61 ) — $ — $ — $ 3,147 $ (61 ) Government agency securities 43 102,044 (1,472 ) 1 993 (7 ) 103,037 (1,479 ) Obligations of state and municipal subdivisions 100 46,186 (2,011 ) 4 1,549 (11 ) 47,735 (2,022 ) Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC 30 67,868 (1,032 ) — — — 67,868 (1,032 ) 174 $ 219,245 $ (4,576 ) 5 $ 2,542 $ (18 ) $ 221,787 $ (4,594 )

Loans, Net and Allowance for 23

Loans, Net and Allowance for Loan Losses (Tables)	3 Months Ended
	Mar. 31, 2017
Receivables [Abstract]
Compositions of Loans	Loans, net, at March 31, 2017 and December 31, 2016, consisted of the following: March 31, December 31, 2017 2016 Commercial $ 601,985 $ 630,805 Real estate: Commercial 2,562,743 2,459,221 Commercial construction, land and land development 573,623 531,481 Residential 647,569 634,545 Single family interim construction 237,740 235,475 Agricultural 52,515 53,548 Consumer 26,224 27,530 Other 112 166 4,702,511 4,572,771 Deferred loan fees (2,427 ) (2,117 ) Allowance for loan losses (33,431 ) (31,591 ) $ 4,666,653 $ 4,539,063
Summary of Activity in Allowance for Loan Losses by Loan Class	The following is a summary of the activity in the allowance for loan losses by loan class for the three months ended March 31, 2017 and 2016 : Commercial Commercial Real Estate, Land and Land Development Residential Real Estate Single-Family Interim Construction Agricultural Consumer Other Unallocated Total Three months ended March 31, 2017 Balance at the beginning of period $ 8,593 $ 18,399 $ 2,760 $ 1,301 $ 207 $ 242 $ 29 $ 60 $ 31,591 Provision for loan losses (590 ) 2,048 67 235 (6 ) 64 23 182 2,023 Charge-offs — — — (134 ) — (56 ) (22 ) — (212 ) Recoveries 2 20 1 — — 2 4 — 29 Balance at end of period $ 8,005 $ 20,467 $ 2,828 $ 1,402 $ 201 $ 252 $ 34 $ 242 $ 33,431 Three months ended March 31, 2016 Balance at the beginning of period $ 10,573 $ 13,007 $ 2,339 $ 769 $ 215 $ 164 $ 8 $ (32 ) $ 27,043 Provision for loan losses 1,592 1,046 133 220 (28 ) (3 ) 22 15 2,997 Charge-offs — (54 ) — — — (1 ) (23 ) — (78 ) Recoveries 8 2 1 — — 2 9 — 22 Balance at end of period $ 12,173 $ 14,001 $ 2,473 $ 989 $ 187 $ 162 $ 16 $ (17 ) $ 29,984 The following table details the amount of the allowance for loan losses and recorded investment in loans by class as of March 31, 2017 and December 31, 2016: Commercial Commercial Real Estate, Land and Land Development Residential Real Estate Single-Family Interim Construction Agricultural Consumer Other Unallocated Total March 31, 2017 Allowance for losses: Individually evaluated for impairment $ 500 $ 4 $ — $ — $ — $ 94 $ — $ — $ 598 Collectively evaluated for impairment 7,505 20,463 2,828 1,402 201 158 34 242 32,833 Loans acquired with deteriorated credit quality — — — — — — — — — Ending balance $ 8,005 $ 20,467 $ 2,828 $ 1,402 $ 201 $ 252 $ 34 $ 242 $ 33,431 Loans: Individually evaluated for impairment $ 8,196 $ 2,843 $ 2,039 $ — $ — $ 264 $ — $ — $ 13,342 Collectively evaluated for impairment 591,823 3,103,643 643,455 237,740 52,515 25,951 112 — 4,655,239 Acquired with deteriorated credit quality 1,966 29,880 2,075 — — 9 — — 33,930 Ending balance $ 601,985 $ 3,136,366 $ 647,569 $ 237,740 $ 52,515 $ 26,224 $ 112 $ — $ 4,702,511 December 31, 2016 Allowance for losses: Individually evaluated for impairment $ 3 $ 4 $ — $ 84 $ — $ 94 $ — $ — $ 185 Collectively evaluated for impairment 8,590 18,395 2,760 1,217 207 148 29 60 31,406 Loans acquired with deteriorated credit quality — — — — — — — — — Ending balance $ 8,593 $ 18,399 $ 2,760 $ 1,301 $ 207 $ 242 $ 29 $ 60 $ 31,591 Loans: Individually evaluated for impairment $ 7,720 $ 7,089 $ 1,889 $ 884 $ — $ 279 $ — $ — $ 17,861 Collectively evaluated for impairment 620,665 2,953,333 630,689 234,591 53,548 27,240 166 — 4,520,232 Acquired with deteriorated credit quality 2,420 30,280 1,967 — — 11 — — 34,678 Ending balance $ 630,805 $ 2,990,702 $ 634,545 $ 235,475 $ 53,548 $ 27,530 $ 166 $ — $ 4,572,771
Summary of Nonperforming Loans by Loan Class	Nonperforming loans by loan class at March 31, 2017 and December 31, 2016, are summarized as follows: Commercial Commercial Real Estate, Land and Land Development Residential Real Estate Single-Family Interim Construction Agricultural Consumer Other Total March 31, 2017 Nonaccrual loans $ 8,196 $ 1,666 $ 1,031 $ — $ — $ 264 $ — $ 11,157 Loans past due 90 days and still accruing — — — — — — — — Troubled debt restructurings (not included in nonaccrual or loans past due and still accruing) — 1,177 1,008 — — — — 2,185 $ 8,196 $ 2,843 $ 2,039 $ — $ — $ 264 $ — $ 13,342 December 31, 2016 Nonaccrual loans $ 7,718 $ 5,885 $ 866 $ 884 $ — $ 273 $ — $ 15,626 Loans past due 90 days and still accruing — — — — — — — — Troubled debt restructurings (not included in nonaccrual or loans past due and still accruing) 1 1,204 1,011 — — — — 2,216 $ 7,719 $ 7,089 $ 1,877 $ 884 $ — $ 273 $ — $ 17,842
Impaired Loans by Loan Class	Impaired loans by loan class at March 31, 2017 and December 31, 2016, are summarized as follows: Commercial Commercial Real Estate, Land and Land Development Residential Real Estate Single-Family Interim Construction Agricultural Consumer Other Total March 31, 2017 Recorded investment in impaired loans: Impaired loans with an allowance for loan losses $ 3,635 $ 77 $ — $ — $ — $ 204 $ — $ 3,916 Impaired loans with no allowance for loan losses 4,561 2,766 2,039 — — 60 — 9,426 Total $ 8,196 $ 2,843 $ 2,039 $ — $ — $ 264 $ — $ 13,342 Unpaid principal balance of impaired loans $ 11,319 $ 2,860 $ 2,249 $ — $ — $ 275 $ — $ 16,703 Allowance for loan losses on impaired loans $ 500 $ 4 $ — $ — $ — $ 94 $ — $ 598 December 31, 2016 Recorded investment in impaired loans: Impaired loans with an allowance for loan losses $ 8 $ 78 $ — $ 168 $ — $ 209 $ — $ 463 Impaired loans with no allowance for loan losses 7,712 7,011 1,889 716 — 70 — 17,398 Total $ 7,720 $ 7,089 $ 1,889 $ 884 $ — $ 279 $ — $ 17,861 Unpaid principal balance of impaired loans $ 10,844 $ 7,133 $ 2,087 $ 884 $ — $ 291 $ — $ 21,239 Allowance for loan losses on impaired loans $ 3 $ 4 $ — $ 84 $ — $ 94 $ — $ 185 For the three months ended March 31, 2017 Average recorded investment in impaired loans $ 7,958 $ 4,966 $ 1,964 $ 442 $ — $ 272 $ — $ 15,602 Interest income recognized on impaired loans $ 2 $ 397 $ 12 $ — $ — $ 1 $ — $ 412 For the three months ended March 31, 2016 Average recorded investment in impaired loans $ 15,677 $ 3,429 $ 3,157 $ — $ 85 $ 94 $ — $ 22,442 Interest income recognized on impaired loans $ 366 $ 36 $ 40 $ — $ — $ — $ — $ 442
Aging of Past Due Loans by Loan Class	The following table presents information regarding the aging of past due loans by loan class as of March 31, 2017 and December 31, 2016: Loans 30-89 Days Past Due Loans 90 or More Past Due Total Past Due Loans Current Loans Total Loans March 31, 2017 Commercial $ 182 $ 8,196 $ 8,378 $ 593,607 $ 601,985 Commercial real estate, land and land development 1,631 1,631 3,262 3,133,104 3,136,366 Residential real estate 2,955 556 3,511 644,058 647,569 Single-family interim construction — — — 237,740 237,740 Agricultural — — — 52,515 52,515 Consumer 36 36 72 26,152 26,224 Other — — — 112 112 $ 4,804 $ 10,419 $ 15,223 $ 4,687,288 $ 4,702,511 December 31, 2016 Commercial $ 226 $ 7,711 $ 7,937 $ 622,868 $ 630,805 Commercial real estate, land and land development 151 6,752 6,903 2,983,799 2,990,702 Residential real estate 846 561 1,407 633,138 634,545 Single-family interim construction 1,062 — 1,062 234,413 235,475 Agricultural 10 — 10 53,538 53,548 Consumer 154 52 206 27,324 27,530 Other — — — 166 166 $ 2,449 $ 15,076 $ 17,525 $ 4,555,246 $ 4,572,771
Summary of Loans by Credit Quality Indicator by Class	A summary of loans by credit quality indicator by class as of March 31, 2017 and December 31, 2016 , is as follows: Pass Pass/ Watch Special Mention Substandard Doubtful Total March 31, 2017 Commercial $ 525,014 $ 34,378 $ 15,563 $ 27,030 $ — $ 601,985 Commercial real estate, construction, land and land development 3,122,652 5,699 4,942 3,073 — 3,136,366 Residential real estate 640,467 3,292 490 3,320 — 647,569 Single-family interim construction 236,803 937 — — — 237,740 Agricultural 39,190 13,100 225 — — 52,515 Consumer 25,931 17 2 274 — 26,224 Other 112 — — — — 112 $ 4,590,169 $ 57,423 $ 21,222 $ 33,697 $ — $ 4,702,511 December 31, 2016 Commercial $ 555,342 $ 31,954 $ 16,734 $ 26,775 $ — $ 630,805 Commercial real estate, construction, land and land development 2,972,732 5,426 5,148 7,396 — 2,990,702 Residential real estate 629,081 1,897 370 3,197 — 634,545 Single-family interim construction 233,800 791 — 884 — 235,475 Agricultural 52,724 569 255 — — 53,548 Consumer 27,215 12 3 300 — 27,530 Other 166 — — — — 166 $ 4,471,060 $ 40,649 $ 22,510 $ 38,552 $ — $ 4,572,771
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period	The carrying amount of all acquired PCI loans included in the consolidated balance sheet and the related outstanding balance at March 31, 2017 and December 31, 2016 were as follows: March 31, 2017 December 31, 2016 Outstanding balance $ 38,380 $ 39,442 Carrying amount 33,930 34,678
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield	The changes in accretable yield during the three months ended March 31, 2017 and 2016 in regard to loans transferred at acquisition for which it was probable that all contractually required payments would not be collected are presented in the table below. For the Three Months Ended March 31, 2017 2016 Balance at January 1, $ 1,526 $ 2,380 Additions — — Accretion (225 ) (302 ) Transfers from nonaccretable 270 — Balance at March 31, $ 1,571 $ 2,078

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	At March 31, 2017 and December 31, 2016 , the approximate amounts of these financial instruments were as follows: March 31, December 31, 2017 2016 Commitments to extend credit $ 873,962 $ 865,668 Standby letters of credit 7,623 10,562 $ 881,585 $ 876,230

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Schedule of Income Tax Expense	Income tax expense for the three months ended March 31, 2017 and 2016 was as follows: Three Months Ended March 31, 2017 2016 Income tax expense for the period $ 6,728 $ 6,162 Effective tax rate 30.0 % 33.1 %

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Assets at Fair Value on Recurring Basis	The following table represents assets reported on the consolidated balance sheets at their fair value on a recurring basis as of March 31, 2017 and December 31, 2016 by level within the ASC Topic 820 fair value measurement hierarchy: Fair Value Measurements at Reporting Date Using Assets/ Liabilities Measured at Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) March 31, 2017 Measured on a recurring basis: Assets: Investment securities available for sale: U.S. treasuries $ 3,158 $ — $ 3,158 $ — Government agency securities 135,708 — 135,708 — Obligations of state and municipal subdivisions 103,366 — 103,366 — Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC 108,177 — 108,177 — December 31, 2016 Measured on a recurring basis: Assets: Investment securities available for sale: U.S. treasuries $ 3,147 $ — $ 3,147 $ — Government agency securities 122,267 — 122,267 — Obligations of state and municipal subdivisions 87,256 — 87,256 — Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC 103,765 — 103,765 —
Assets and Liabilities at Fair Value on Nonrecurring Basis	The following table presents the assets carried on the consolidated balance sheet by caption and by level in the fair value hierarchy at March 31, 2017 and December 31, 2016, for which a nonrecurring change in fair value has been recorded: Fair Value Measurements at Reporting Date Using Assets Measured at Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Period Ended Total Losses March 31, 2017 Measured on a nonrecurring basis: Assets: Impaired loans $ 3,135 $ — $ — $ 3,135 $ 500 Other real estate — — — — — December 31, 2016 Measured on a nonrecurring basis: Assets: Impaired loans $ 968 $ — $ — $ 968 $ 708 Other real estate 340 — — 340 52
Carrying Amount and Estimated Fair Value of Financial Instruments	The carrying amount, estimated fair value and the level of the fair value hierarchy of the Company’s financial instruments were as follows at March 31, 2017 and December 31, 2016: Fair Value Measurements at Reporting Date Using Carrying Amount Estimated Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) March 31, 2017 Financial assets: Cash and cash equivalents $ 515,123 $ 515,123 $ 515,123 $ — $ — Certificates of deposit held in other banks 5,892 5,943 — 5,943 — Securities available for sale 350,409 350,409 — 350,409 — Loans held for sale 5,081 5,081 — 5,081 — Loans, net 4,666,653 4,636,219 — 4,632,901 3,318 FHLB of Dallas stock and other restricted stock 26,672 26,672 — 26,672 — Accrued interest receivable 11,410 11,410 — 11,410 — Financial liabilities: Deposits 4,722,203 4,726,879 — 4,726,879 — Accrued interest payable 2,398 2,398 — 2,398 — FHLB advances 460,727 469,430 — 469,430 — Other borrowings 107,388 110,550 — 110,550 — Junior subordinated debentures 18,147 18,140 — 18,140 — Off-balance sheet assets (liabilities): Commitments to extend credit — — — — — Standby letters of credit — — — — — December 31, 2016 Financial assets: Cash and cash equivalents $ 505,027 $ 505,027 $ 505,027 $ — $ — Certificates of deposit held in other banks 2,707 2,733 — 2,733 — Securities available for sale 316,435 316,435 — 316,435 — Loans held for sale 9,795 9,795 — 9,795 — Loans, net 4,539,063 4,532,364 — 4,532,086 278 FHLB of Dallas stock and other restricted stock 26,536 26,536 — 26,536 — Accrued interest receivable 12,331 12,331 — 12,331 — Financial liabilities: Deposits 4,577,109 4,581,866 — 4,581,866 — Accrued interest payable 4,020 4,020 — 4,020 — FHLB advances 460,746 459,436 — 459,436 — Other borrowings 107,299 110,000 — 110,000 — Junior subordinated debentures 18,147 18,131 — 18,131 — Off-balance sheet assets (liabilities): Commitments to extend credit — — — — — Standby letters of credit — — — — —

Stock Awards and Stock Warran27

Stock Awards and Stock Warrants (Tables)	3 Months Ended
	Mar. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Nonvested Shares Activity	The following table summarizes the activity in nonvested shares for the three months ended March 31, 2017 and 2016 : Number of Shares Weighted Average Grant Date Fair Value Nonvested shares, December 31, 2016 280,524 $ 36.88 Granted during the period 40,627 62.37 Vested during the period (65,668 ) 31.23 Forfeited during the period — — Nonvested shares, March 31, 2017 255,483 $ 42.38 Nonvested shares, December 31, 2015 373,572 $ 40.29 Granted during the period 66,220 29.91 Vested during the period (44,220 ) 32.61 Forfeited during the period (6,334 ) 42.25 Nonvested shares, March 31, 2016 389,238 $ 39.20
Schedule of Vesting of Restricted Stock Award	At March 31, 2017 , the future vesting schedule of the nonvested shares is as follows: First year 124,575 Second year 79,482 Third year 41,526 Fourth year 6,050 Fifth year 3,850 Total nonvested shares 255,483

Regulatory Matters (Tables)

Regulatory Matters (Tables)	3 Months Ended
	Mar. 31, 2017
Regulated Operations [Abstract]
Schedule of Compliance with Regulatory Capital Requirements	The actual capital amounts and ratios of the Company and Bank as of March 31, 2017 and December 31, 2016, are presented in the following table: Actual Minimum for Capital Adequacy Purposes To Be Well Capitalized Under Prompt Corrective Action Provisions Amount Ratio Amount Ratio Amount Ratio March 31, 2017 Total capital to risk weighted assets: Consolidated $ 583,864 11.44 % $ 408,474 8.00 % N/A N/A Bank 572,757 11.22 408,247 8.00 $ 510,309 10.00 % Tier 1 capital to risk weighted assets: Consolidated 440,433 8.63 306,356 6.00 N/A N/A Bank 539,326 10.57 306,185 6.00 408,247 8.00 Common equity tier 1 to risk weighted assets Consolidated 422,833 8.28 229,767 4.50 N/A N/A Bank 539,326 10.57 229,639 4.50 331,701 6.50 Tier 1 capital to average assets: Consolidated 440,433 7.84 224,601 4.00 N/A N/A Bank 539,326 9.61 224,491 4.00 280,614 5.00 December 31, 2016 Total capital to risk weighted assets: Consolidated $ 568,808 11.38 % $ 399,698 8.00 % N/A N/A Bank 558,551 11.19 399,497 8.00 $ 499,371 10.00 % Tier 1 capital to risk weighted assets: Consolidated 427,217 8.55 299,774 6.00 N/A N/A Bank 526,960 10.55 299,623 6.00 399,497 8.00 Common equity tier 1 to risk weighted assets Consolidated 409,617 8.20 224,830 4.50 N/A N/A Bank 526,960 10.55 224,717 4.50 324,591 6.50 Tier 1 capital to average assets: Consolidated 427,217 7.82 218,612 4.00 N/A N/A Bank 526,960 9.65 218,517 4.00 273,146 5.00

Subsequent Event (Tables)

Subsequent Event (Tables)	3 Months Ended
	Mar. 31, 2017
Subsequent Events [Abstract]
Schedule of Assets Acquired and Liabilities Assumed	Estimated fair values of the assets acquired and liabilities assumed in this transaction as of the closing date are as follows: Assets of acquired bank: Cash and cash equivalents $ 159,469 Securities available for sale 336,506 Loans 1,396,169 Premises and equipment 63,581 Other real estate owned 10,666 Goodwill 362,922 Core deposit intangible 15,623 Other assets 92,696 Total assets acquired $ 2,437,632 Liabilities of acquired bank: Deposits $ 1,834,655 Junior subordinated debentures 12,566 Other liabilities 20,893 Total liabilities assumed $ 1,868,114 Common stock issued at $62.70 per share $ 552,055 Cash paid $ 17,463

Summary of Significant Accoun30

Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)segment
Accounting Policies [Abstract]
Number of reportable segments (segment) | segment	1
Effective income tax rate reconciliation, share-based compensation, excess tax benefit amount | $	$ 724

Summary of Significant Accoun31

Summary of Significant Accounting Policies - EPS (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Basic earnings per share:
Net income	$ 15,671	$ 12,452
Less: Preferred stock dividends	0	(8)
Net income after preferred stock dividends	15,671	12,444
Undistributed earnings allocated to participating securities	176	211
Dividends paid on participating securities	24	28
Net income available to common shareholders	$ 15,471	$ 12,205
Weighted-average basic shares outstanding (shares)	18,667,274	18,089,853
Basic earnings per share (usd per share)	$ 0.83	$ 0.67
Diluted earnings per share:
Add dilutive stock warrants (shares)	107,132	61,492
Add dilutive participating securities (shares)	0	22,255
Total weighted-average diluted shares outstanding (shares)	18,774,406	18,173,600
Diluted earnings per share (usd per share)	$ 0.82	$ 0.67
Anti-dilutive participating securities (shares)	126,847	0

Statement of Cash Flows - Other

Statement of Cash Flows - Other Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash transactions:
Interest expense paid	$ 9,694	$ 6,823
Income taxes paid	0	760
Noncash transactions:
Transfers of loans to other real estate owned	750	0
Securities purchased, not yet settled	6,068	0
Excess tax deficiency on restricted stock vested	0	(83)
Transfer of repurchase agreements to deposits	$ 0	$ 20,688

Statement of Cash Flows - Suppl

Statement of Cash Flows - Supplemental Investing Noncash Activities from Acquisition (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Assets acquired:
Loans	$ 0	$ 735
Goodwill	0	(324)
Core deposit intangibles	0	(216)
Deferred tax asset	0	(175)
Total assets	0	20
Liabilities assumed:
Other liabilities	0	20
Total liabilities	$ 0	$ 20

Securities Available for Sale -

Securities Available for Sale - Additional Information (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Available-for-sale Securities [Abstract]
Carrying value of securities pledged	$ 169,770	$ 176,457

Securities Available for Sale35

Securities Available for Sale - Amortized Cost of Securities and Approximate Fair Values (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 351,014	$ 319,040
Gross Unrealized Gains	2,509	1,989
Gross Unrealized Losses	(3,114)	(4,594)
Fair Value	350,409	316,435
U.S. treasuries
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,196	3,208
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(38)	(61)
Fair Value	3,158	3,147
Government agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	136,621	123,605
Gross Unrealized Gains	165	141
Gross Unrealized Losses	(1,078)	(1,479)
Fair Value	135,708	122,267
Obligations of state and municipal subdivisions
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	103,554	88,358
Gross Unrealized Gains	1,259	920
Gross Unrealized Losses	(1,447)	(2,022)
Fair Value	103,366	87,256
Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	107,643	103,869
Gross Unrealized Gains	1,085	928
Gross Unrealized Losses	(551)	(1,032)
Fair Value	$ 108,177	$ 103,765

Securities Available for Sale36

Securities Available for Sale - Amortized Cost and Estimated Fair Value of Securities Available for Sale by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Amortized Cost
Due in one year or less	$ 31,149
Due from one year to five years	113,221
Due from five to ten years	37,014
Thereafter	61,987
Total	243,371
Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC	107,643
Amortized Cost	351,014	$ 319,040
Fair Value
Due in one year or less	31,132
Due from one year to five years	112,685
Due from five to ten years	36,601
Thereafter	61,814
Total	242,232
Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC	108,177
Fair Value	$ 350,409	$ 316,435

Securities Available for Sale37

Securities Available for Sale - Summary of Unrealized Losses and Fair Value of Securities in Continuous Unrealized Loss Positions (Details) $ in Thousands	Mar. 31, 2017USD ($)security	Dec. 31, 2016USD ($)security
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Number of Securities | security	150	174
Less than 12 months: Estimated Fair Value	$ 216,337	$ 219,245
Less than 12 months: Unrealized Losses	$ (3,079)	$ (4,576)
Greater Than 12 Months, Number of Securities | security	6	5
Greater Than 12 Months: Estimated Fair Value	$ 3,180	$ 2,542
Greater Than 12 Months: Unrealized Losses	(35)	(18)
Total: Estimated Fair Value	219,517	221,787
Total: Unrealized Losses	$ (3,114)	$ (4,594)
U.S. treasuries
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Number of Securities | security	1	1
Less than 12 months: Estimated Fair Value	$ 3,158	$ 3,147
Less than 12 months: Unrealized Losses	$ (38)	$ (61)
Greater Than 12 Months, Number of Securities | security	0	0
Greater Than 12 Months: Estimated Fair Value	$ 0	$ 0
Greater Than 12 Months: Unrealized Losses	0	0
Total: Estimated Fair Value	3,158	3,147
Total: Unrealized Losses	$ (38)	$ (61)
Government agency securities
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Number of Securities | security	45	43
Less than 12 months: Estimated Fair Value	$ 104,389	$ 102,044
Less than 12 months: Unrealized Losses	$ (1,072)	$ (1,472)
Greater Than 12 Months, Number of Securities | security	1	1
Greater Than 12 Months: Estimated Fair Value	$ 995	$ 993
Greater Than 12 Months: Unrealized Losses	(6)	(7)
Total: Estimated Fair Value	105,384	103,037
Total: Unrealized Losses	$ (1,078)	$ (1,479)
Obligations of state and municipal subdivisions
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Number of Securities | security	76	100
Less than 12 months: Estimated Fair Value	$ 38,076	$ 46,186
Less than 12 months: Unrealized Losses	$ (1,418)	$ (2,011)
Greater Than 12 Months, Number of Securities | security	5	4
Greater Than 12 Months: Estimated Fair Value	$ 2,185	$ 1,549
Greater Than 12 Months: Unrealized Losses	(29)	(11)
Total: Estimated Fair Value	40,261	47,735
Total: Unrealized Losses	$ (1,447)	$ (2,022)
Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Number of Securities | security	28	30
Less than 12 months: Estimated Fair Value	$ 70,714	$ 67,868
Less than 12 months: Unrealized Losses	$ (551)	$ (1,032)
Greater Than 12 Months, Number of Securities | security	0	0
Greater Than 12 Months: Estimated Fair Value	$ 0	$ 0
Greater Than 12 Months: Unrealized Losses	0	0
Total: Estimated Fair Value	70,714	67,868
Total: Unrealized Losses	$ (551)	$ (1,032)

Loans, Net and Allowance for 38

Loans, Net and Allowance for Loan Losses - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)componentmodified_loancontract	Mar. 31, 2016modified_loancontract	Dec. 31, 2016USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net	$ 4,666,653		$ 4,539,063
Number of components allowance for loan losses is derived from | component	2
Recorded investment in troubled debt restructuring including nonaccrual	$ 2,389		2,425
Number of loans modified under trouble debt restructuring | contract	0	0
Number of loans modified under troubled debt restructuring during previous twelve months | modified_loan	0	0
Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans requiring external review (greater than)	$ 2,900
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of total loan portfolio (less than)	1.00%
Exploration and Production Energy Loans | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net	$ 97,200		$ 115,300
Real Estate Loan | Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan to value ratio (percent)	80.00%
Loan, amortization period	20 years
Non-Real Estate Loan | Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Period of operating lines	1 year

Loans, Net and Allowance for 39

Loans, Net and Allowance for Loan Losses - Composition of Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	$ 4,702,511	$ 4,572,771
Deferred loan fees	(2,427)	(2,117)
Allowance for loan losses	(33,431)	(31,591)	$ (29,984)	$ (27,043)
Loans, net	4,666,653	4,539,063
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	601,985	630,805
Allowance for loan losses	(8,005)	(8,593)	(12,173)	(10,573)
Real estate | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	2,562,743	2,459,221
Real estate | Commercial construction, land and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	573,623	531,481
Real estate | Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	647,569	634,545
Allowance for loan losses	(2,828)	(2,760)
Real estate | Single family interim construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	237,740	235,475
Allowance for loan losses	(1,402)	(1,301)
Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	52,515	53,548
Allowance for loan losses	(201)	(207)	(187)	(215)
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	26,224	27,530
Allowance for loan losses	(252)	(242)	(162)	(164)
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, gross	112	166
Allowance for loan losses	$ (34)	$ (29)	$ (16)	$ (8)

Loans, Net and Allowance for 40

Loans, Net and Allowance for Loan Losses - Rollforward of Activity in Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of period	$ 31,591	$ 27,043
Provision for loan losses	2,023	2,997
Charge-offs	(212)	(78)
Recoveries	29	22
Balance at end of period	33,431	29,984
Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of period	8,593	10,573
Provision for loan losses	(590)	1,592
Charge-offs	0	0
Recoveries	2	8
Balance at end of period	8,005	12,173
Agricultural
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of period	207	215
Provision for loan losses	(6)	(28)
Charge-offs	0	0
Recoveries	0	0
Balance at end of period	201	187
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of period	242	164
Provision for loan losses	64	(3)
Charge-offs	(56)	(1)
Recoveries	2	2
Balance at end of period	252	162
Other
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of period	29	8
Provision for loan losses	23	22
Charge-offs	(22)	(23)
Recoveries	4	9
Balance at end of period	34	16
Unallocated
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of period	60	(32)
Provision for loan losses	182	15
Charge-offs	0	0
Recoveries	0	0
Balance at end of period	242	(17)
Commercial Real Estate, Land and Land Development | Real estate
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of period	18,399	13,007
Provision for loan losses	2,048	1,046
Charge-offs	0	(54)
Recoveries	20	2
Balance at end of period	20,467	14,001
Residential Real Estate | Real estate
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of period	2,760	2,339
Provision for loan losses	67	133
Charge-offs	0	0
Recoveries	1	1
Balance at end of period	2,828	2,473
Single-Family Interim Construction | Real estate
Allowance for Loan and Lease Losses [Roll Forward]
Balance at the beginning of period	1,301	769
Provision for loan losses	235	220
Charge-offs	(134)	0
Recoveries	0	0
Balance at end of period	$ 1,402	$ 989

Loans, Net and Allowance for 41

Loans, Net and Allowance for Loan Losses - Summary of Activity in Allowance for Loan Losses by Loan Class (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Allowance for losses:
Individually evaluated for impairment	$ 598	$ 185
Collectively evaluated for impairment	32,833	31,406
Ending balance	33,431	31,591	$ 29,984	$ 27,043
Loans:
Individually evaluated for impairment	13,342	17,861
Collectively evaluated for impairment	4,655,239	4,520,232
Ending balance	4,702,511	4,572,771
Commercial
Allowance for losses:
Individually evaluated for impairment	500	3
Collectively evaluated for impairment	7,505	8,590
Ending balance	8,005	8,593	12,173	10,573
Loans:
Individually evaluated for impairment	8,196	7,720
Collectively evaluated for impairment	591,823	620,665
Ending balance	601,985	630,805
Agricultural
Allowance for losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	201	207
Ending balance	201	207	187	215
Loans:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	52,515	53,548
Ending balance	52,515	53,548
Consumer
Allowance for losses:
Individually evaluated for impairment	94	94
Collectively evaluated for impairment	158	148
Ending balance	252	242	162	164
Loans:
Individually evaluated for impairment	264	279
Collectively evaluated for impairment	25,951	27,240
Ending balance	26,224	27,530
Other
Allowance for losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	34	29
Ending balance	34	29	16	8
Loans:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	112	166
Ending balance	112	166
Unallocated
Allowance for losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	242	60
Ending balance	242	60	$ (17)	$ (32)
Loans:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	0	0
Ending balance	0	0
Receivables Acquired with Deteriorated Credit Quality
Allowance for losses:
Loans acquired with deteriorated credit quality	0	0
Loans:
Acquired with deteriorated credit quality	33,930	34,678
Receivables Acquired with Deteriorated Credit Quality | Commercial
Allowance for losses:
Loans acquired with deteriorated credit quality	0	0
Loans:
Acquired with deteriorated credit quality	1,966	2,420
Receivables Acquired with Deteriorated Credit Quality | Agricultural
Allowance for losses:
Loans acquired with deteriorated credit quality	0	0
Loans:
Acquired with deteriorated credit quality	0	0
Receivables Acquired with Deteriorated Credit Quality | Consumer
Allowance for losses:
Loans acquired with deteriorated credit quality	0	0
Loans:
Acquired with deteriorated credit quality	9	11
Receivables Acquired with Deteriorated Credit Quality | Other
Allowance for losses:
Loans acquired with deteriorated credit quality	0	0
Loans:
Acquired with deteriorated credit quality	0	0
Receivables Acquired with Deteriorated Credit Quality | Unallocated
Allowance for losses:
Loans acquired with deteriorated credit quality	0	0
Loans:
Acquired with deteriorated credit quality	0	0
Commercial Real Estate, Land and Land Development | Real estate
Allowance for losses:
Individually evaluated for impairment	4	4
Collectively evaluated for impairment	20,463	18,395
Ending balance	20,467	18,399
Loans:
Individually evaluated for impairment	2,843	7,089
Collectively evaluated for impairment	3,103,643	2,953,333
Ending balance	3,136,366	2,990,702
Commercial Real Estate, Land and Land Development | Receivables Acquired with Deteriorated Credit Quality | Real estate
Allowance for losses:
Loans acquired with deteriorated credit quality	0	0
Loans:
Acquired with deteriorated credit quality	29,880	30,280
Residential | Real estate
Allowance for losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	2,828	2,760
Ending balance	2,828	2,760
Loans:
Individually evaluated for impairment	2,039	1,889
Collectively evaluated for impairment	643,455	630,689
Ending balance	647,569	634,545
Residential | Receivables Acquired with Deteriorated Credit Quality | Real estate
Allowance for losses:
Loans acquired with deteriorated credit quality	0	0
Loans:
Acquired with deteriorated credit quality	2,075	1,967
Single family interim construction | Real estate
Allowance for losses:
Individually evaluated for impairment	0	84
Collectively evaluated for impairment	1,402	1,217
Ending balance	1,402	1,301
Loans:
Individually evaluated for impairment	0	884
Collectively evaluated for impairment	237,740	234,591
Ending balance	237,740	235,475
Single family interim construction | Receivables Acquired with Deteriorated Credit Quality | Real estate
Allowance for losses:
Loans acquired with deteriorated credit quality	0	0
Loans:
Acquired with deteriorated credit quality	$ 0	$ 0

Loans, Net and Allowance for 42

Loans, Net and Allowance for Loan Losses - Summary of Non Performing Loans by Loan Class (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 11,157	$ 15,626
Loans past due 90 days and still accruing	0	0
Troubled debt restructurings (not included in nonaccrual or loans past due and still accruing)	2,185	2,216
Total nonperforming loans	13,342	17,842
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	8,196	7,718
Loans past due 90 days and still accruing	0	0
Troubled debt restructurings (not included in nonaccrual or loans past due and still accruing)	0	1
Total nonperforming loans	8,196	7,719
Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	0	0
Loans past due 90 days and still accruing	0	0
Troubled debt restructurings (not included in nonaccrual or loans past due and still accruing)	0	0
Total nonperforming loans	0	0
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	264	273
Loans past due 90 days and still accruing	0	0
Troubled debt restructurings (not included in nonaccrual or loans past due and still accruing)	0	0
Total nonperforming loans	264	273
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	0	0
Loans past due 90 days and still accruing	0	0
Troubled debt restructurings (not included in nonaccrual or loans past due and still accruing)	0	0
Total nonperforming loans	0	0
Commercial Real Estate, Land and Land Development | Real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	1,666	5,885
Loans past due 90 days and still accruing	0	0
Troubled debt restructurings (not included in nonaccrual or loans past due and still accruing)	1,177	1,204
Total nonperforming loans	2,843	7,089
Residential Real Estate | Real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	1,031	866
Loans past due 90 days and still accruing	0	0
Troubled debt restructurings (not included in nonaccrual or loans past due and still accruing)	1,008	1,011
Total nonperforming loans	2,039	1,877
Single-Family Interim Construction | Real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	0	884
Loans past due 90 days and still accruing	0	0
Troubled debt restructurings (not included in nonaccrual or loans past due and still accruing)	0	0
Total nonperforming loans	$ 0	$ 884

Loans, Net and Allowance for 43

Loans, Net and Allowance for Loan Losses - Impaired Loans by Loan Class (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Recorded investment in impaired loans:
Impaired loans with an allowance for loan losses	$ 3,916		$ 463
Impaired loans with no allowance for loan losses	9,426		17,398
Total	13,342		17,861
Unpaid principal balance of impaired loans	16,703		21,239
Allowance for loan losses on impaired loans	598		185
Average recorded investment in impaired loans	15,602	$ 22,442
Interest income recognized on impaired loans	412	442
Commercial
Recorded investment in impaired loans:
Impaired loans with an allowance for loan losses	3,635		8
Impaired loans with no allowance for loan losses	4,561		7,712
Total	8,196		7,720
Unpaid principal balance of impaired loans	11,319		10,844
Allowance for loan losses on impaired loans	500		3
Average recorded investment in impaired loans	7,958	15,677
Interest income recognized on impaired loans	2	366
Agricultural
Recorded investment in impaired loans:
Impaired loans with an allowance for loan losses	0		0
Impaired loans with no allowance for loan losses	0		0
Total	0		0
Unpaid principal balance of impaired loans	0		0
Allowance for loan losses on impaired loans	0		0
Average recorded investment in impaired loans	0	85
Interest income recognized on impaired loans	0	0
Consumer
Recorded investment in impaired loans:
Impaired loans with an allowance for loan losses	204		209
Impaired loans with no allowance for loan losses	60		70
Total	264		279
Unpaid principal balance of impaired loans	275		291
Allowance for loan losses on impaired loans	94		94
Average recorded investment in impaired loans	272	94
Interest income recognized on impaired loans	1	0
Other
Recorded investment in impaired loans:
Impaired loans with an allowance for loan losses	0		0
Impaired loans with no allowance for loan losses	0		0
Total	0		0
Unpaid principal balance of impaired loans	0		0
Allowance for loan losses on impaired loans	0		0
Average recorded investment in impaired loans	0	0
Interest income recognized on impaired loans	0	0
Commercial Real Estate, Land and Land Development | Real estate
Recorded investment in impaired loans:
Impaired loans with an allowance for loan losses	77		78
Impaired loans with no allowance for loan losses	2,766		7,011
Total	2,843		7,089
Unpaid principal balance of impaired loans	2,860		7,133
Allowance for loan losses on impaired loans	4		4
Average recorded investment in impaired loans	4,966	3,429
Interest income recognized on impaired loans	397	36
Residential Real Estate | Real estate
Recorded investment in impaired loans:
Impaired loans with an allowance for loan losses	0		0
Impaired loans with no allowance for loan losses	2,039		1,889
Total	2,039		1,889
Unpaid principal balance of impaired loans	2,249		2,087
Allowance for loan losses on impaired loans	0		0
Average recorded investment in impaired loans	1,964	3,157
Interest income recognized on impaired loans	12	40
Single-Family Interim Construction | Real estate
Recorded investment in impaired loans:
Impaired loans with an allowance for loan losses	0		168
Impaired loans with no allowance for loan losses	0		716
Total	0		884
Unpaid principal balance of impaired loans	0		884
Allowance for loan losses on impaired loans	0		$ 84
Average recorded investment in impaired loans	442	0
Interest income recognized on impaired loans	$ 0	$ 0

Loans, Net and Allowance for 44

Loans, Net and Allowance for Loan Losses - Aging of Past Due Loans by Loan Class (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	$ 15,223	$ 17,525
Current Loans	4,687,288	4,555,246
Ending balance	4,702,511	4,572,771
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	8,378	7,937
Current Loans	593,607	622,868
Ending balance	601,985	630,805
Agricultural
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	0	10
Current Loans	52,515	53,538
Ending balance	52,515	53,548
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	72	206
Current Loans	26,152	27,324
Ending balance	26,224	27,530
Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	0	0
Current Loans	112	166
Ending balance	112	166
Loans 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	4,804	2,449
Loans 30-89 Days Past Due | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	182	226
Loans 30-89 Days Past Due | Agricultural
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	0	10
Loans 30-89 Days Past Due | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	36	154
Loans 30-89 Days Past Due | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	0	0
Loans 90 or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	10,419	15,076
Loans 90 or More Past Due | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	8,196	7,711
Loans 90 or More Past Due | Agricultural
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	0	0
Loans 90 or More Past Due | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	36	52
Loans 90 or More Past Due | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	0	0
Commercial Real Estate, Land and Land Development | Real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	3,262	6,903
Current Loans	3,133,104	2,983,799
Ending balance	3,136,366	2,990,702
Commercial Real Estate, Land and Land Development | Loans 30-89 Days Past Due | Real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	1,631	151
Commercial Real Estate, Land and Land Development | Loans 90 or More Past Due | Real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	1,631	6,752
Residential | Real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	3,511	1,407
Current Loans	644,058	633,138
Ending balance	647,569	634,545
Residential | Loans 30-89 Days Past Due | Real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	2,955	846
Residential | Loans 90 or More Past Due | Real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	556	561
Single family interim construction | Real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	0	1,062
Current Loans	237,740	234,413
Ending balance	237,740	235,475
Single family interim construction | Loans 30-89 Days Past Due | Real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	0	1,062
Single family interim construction | Loans 90 or More Past Due | Real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans past due	$ 0	$ 0

Loans, Net and Allowance for 45

Loans, Net and Allowance for Loan Losses - Summary of Loans by Credit Quality Indicator (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	$ 4,702,511	$ 4,572,771
Pass
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	4,590,169	4,471,060
Pass/ Watch
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	57,423	40,649
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	21,222	22,510
Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	33,697	38,552
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	0	0
Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	601,985	630,805
Commercial | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	525,014	555,342
Commercial | Pass/ Watch
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	34,378	31,954
Commercial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	15,563	16,734
Commercial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	27,030	26,775
Commercial | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	0	0
Real estate | Commercial Real Estate, Construction, Land and Land Development [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	3,136,366	2,990,702
Real estate | Commercial Real Estate, Construction, Land and Land Development [Member] | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	3,122,652	2,972,732
Real estate | Commercial Real Estate, Construction, Land and Land Development [Member] | Pass/ Watch
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	5,699	5,426
Real estate | Commercial Real Estate, Construction, Land and Land Development [Member] | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	4,942	5,148
Real estate | Commercial Real Estate, Construction, Land and Land Development [Member] | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	3,073	7,396
Real estate | Commercial Real Estate, Construction, Land and Land Development [Member] | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	0	0
Real estate | Residential
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	647,569	634,545
Real estate | Residential | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	640,467	629,081
Real estate | Residential | Pass/ Watch
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	3,292	1,897
Real estate | Residential | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	490	370
Real estate | Residential | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	3,320	3,197
Real estate | Residential | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	0	0
Real estate | Single family interim construction
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	237,740	235,475
Real estate | Single family interim construction | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	236,803	233,800
Real estate | Single family interim construction | Pass/ Watch
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	937	791
Real estate | Single family interim construction | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	0	0
Real estate | Single family interim construction | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	0	884
Real estate | Single family interim construction | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	0	0
Agricultural
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	52,515	53,548
Agricultural | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	39,190	52,724
Agricultural | Pass/ Watch
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	13,100	569
Agricultural | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	225	255
Agricultural | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	0	0
Agricultural | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	0	0
Consumer
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	26,224	27,530
Consumer | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	25,931	27,215
Consumer | Pass/ Watch
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	17	12
Consumer | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	2	3
Consumer | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	274	300
Consumer | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	0	0
Other
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	112	166
Other | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	112	166
Other | Pass/ Watch
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	0	0
Other | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	0	0
Other | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	0	0
Other | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans, gross	$ 0	$ 0

Loans, Net and Allowance for 46

Loans, Net and Allowance for Loan Losses - Purchased Credit Impaired Loans in Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Outstanding balance	$ 38,380	$ 39,442
Carrying amount	$ 33,930	$ 34,678

Loans, Net and Allowance for 47

Loans, Net and Allowance for Loan Losses - Accretable Yield Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance at January 1,	$ 1,526	$ 2,380
Additions	0	0
Accretion	(225)	(302)
Transfers from nonaccretable	270	0
Balance at March 31,	$ 1,571	$ 2,078

Commitments and Contingencies48

Commitments and Contingencies (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial instruments with off-balance sheet risk	$ 881,585	$ 876,230
Commitments to extend credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial instruments with off-balance sheet risk	873,962	865,668
Standby letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial instruments with off-balance sheet risk	$ 7,623	$ 10,562

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Rent expense	$ 681	$ 675

Income Taxes - Tax Expense (Det

Income Taxes - Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Income tax expense for the period	$ 6,728	$ 6,162
Effective tax rates (percent)	30.00%	33.10%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Federal income tax at statutory rate (percent)	35.00%	35.00%

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
U.S. treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale measured on a recurring basis	$ 3,158	$ 3,147
Government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale measured on a recurring basis	135,708	122,267
Obligations of state and municipal subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale measured on a recurring basis	103,366	87,256
Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale measured on a recurring basis	108,177	103,765
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale measured on a recurring basis	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale measured on a recurring basis	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Obligations of state and municipal subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale measured on a recurring basis	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale measured on a recurring basis	0	0
Significant Other Observable Inputs (Level 2) | U.S. treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale measured on a recurring basis	3,158	3,147
Significant Other Observable Inputs (Level 2) | Government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale measured on a recurring basis	135,708	122,267
Significant Other Observable Inputs (Level 2) | Obligations of state and municipal subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale measured on a recurring basis	103,366	87,256
Significant Other Observable Inputs (Level 2) | Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale measured on a recurring basis	108,177	103,765
Significant Unobservable Inputs (Level 3) | U.S. treasuries
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale measured on a recurring basis	0	0
Significant Unobservable Inputs (Level 3) | Government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale measured on a recurring basis	0	0
Significant Unobservable Inputs (Level 3) | Obligations of state and municipal subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale measured on a recurring basis	0	0
Significant Unobservable Inputs (Level 3) | Residential pass-through securities guaranteed by FNMA, GNMA and FHLMC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale measured on a recurring basis	$ 0	$ 0

Fair Value Measurements - Ass53

Fair Value Measurements - Assets and Liabilities at Fair Value on Nonrecurring Basis (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Impaired loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets Measured at Fair Value	$ 3,135	$ 968
Period Ended Total Losses	500	708
Other real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets Measured at Fair Value	0	340
Period Ended Total Losses	0	52
Quoted Prices in Active Markets for Identical Assets (Level 1) | Impaired loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets Measured at Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets Measured at Fair Value	0	0
Significant Other Observable Inputs (Level 2) | Impaired loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets Measured at Fair Value	0	0
Significant Other Observable Inputs (Level 2) | Other real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets Measured at Fair Value	0	0
Significant Unobservable Inputs (Level 3) | Impaired loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets Measured at Fair Value	3,135	968
Significant Unobservable Inputs (Level 3) | Other real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets Measured at Fair Value	$ 0	$ 340

Fair Value Measurements - Carry

Fair Value Measurements - Carrying Amount and Estimated Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financial assets:
Securities available for sale	$ 350,409	$ 316,435
Off-balance sheet assets (liabilities):
Financial instruments with off-balance sheet risk	881,585	876,230
Commitments to extend credit
Off-balance sheet assets (liabilities):
Financial instruments with off-balance sheet risk	873,962	865,668
Standby letters of credit
Off-balance sheet assets (liabilities):
Financial instruments with off-balance sheet risk	7,623	10,562
Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets:
Cash and cash equivalents	515,123	505,027
Certificates of deposit held in other banks	0	0
Securities available for sale	0	0
Loans held for sale	0	0
Loans, net	0	0
FHLB of Dallas stock and other restricted stock	0	0
Accrued interest receivable	0	0
Financial liabilities:
Deposits	0	0
Accrued interest payable	0	0
FHLB advances	0	0
Other borrowings	0	0
Junior subordinated debentures	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Commitments to extend credit
Off-balance sheet assets (liabilities):
Financial instruments with off-balance sheet risk	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Standby letters of credit
Off-balance sheet assets (liabilities):
Financial instruments with off-balance sheet risk	0	0
Significant Other Observable Inputs (Level 2)
Financial assets:
Cash and cash equivalents	0	0
Certificates of deposit held in other banks	5,943	2,733
Securities available for sale	350,409	316,435
Loans held for sale	5,081	9,795
Loans, net	4,632,901	4,532,086
FHLB of Dallas stock and other restricted stock	26,672	26,536
Accrued interest receivable	11,410	12,331
Financial liabilities:
Deposits	4,726,879	4,581,866
Accrued interest payable	2,398	4,020
FHLB advances	469,430	459,436
Other borrowings	110,550	110,000
Junior subordinated debentures	18,140	18,131
Significant Other Observable Inputs (Level 2) | Commitments to extend credit
Off-balance sheet assets (liabilities):
Financial instruments with off-balance sheet risk	0	0
Significant Other Observable Inputs (Level 2) | Standby letters of credit
Off-balance sheet assets (liabilities):
Financial instruments with off-balance sheet risk	0	0
Significant Unobservable Inputs (Level 3)
Financial assets:
Cash and cash equivalents	0	0
Certificates of deposit held in other banks	0	0
Securities available for sale	0	0
Loans held for sale	0	0
Loans, net	3,318	278
FHLB of Dallas stock and other restricted stock	0	0
Accrued interest receivable	0	0
Financial liabilities:
Deposits	0	0
Accrued interest payable	0	0
FHLB advances	0	0
Other borrowings	0	0
Junior subordinated debentures	0	0
Significant Unobservable Inputs (Level 3) | Commitments to extend credit
Off-balance sheet assets (liabilities):
Financial instruments with off-balance sheet risk	0	0
Significant Unobservable Inputs (Level 3) | Standby letters of credit
Off-balance sheet assets (liabilities):
Financial instruments with off-balance sheet risk	0	0
Carrying Amount
Financial assets:
Cash and cash equivalents	515,123	505,027
Certificates of deposit held in other banks	5,892	2,707
Securities available for sale	350,409	316,435
Loans held for sale	5,081	9,795
Loans, net	4,666,653	4,539,063
FHLB of Dallas stock and other restricted stock	26,672	26,536
Accrued interest receivable	11,410	12,331
Financial liabilities:
Deposits	4,722,203	4,577,109
Accrued interest payable	2,398	4,020
FHLB advances	460,727	460,746
Other borrowings	107,388	107,299
Junior subordinated debentures	18,147	18,147
Carrying Amount | Commitments to extend credit
Off-balance sheet assets (liabilities):
Financial instruments with off-balance sheet risk	0	0
Carrying Amount | Standby letters of credit
Off-balance sheet assets (liabilities):
Financial instruments with off-balance sheet risk	0	0
Estimated Fair Value
Financial assets:
Cash and cash equivalents	515,123	505,027
Certificates of deposit held in other banks	5,943	2,733
Securities available for sale	350,409	316,435
Loans held for sale	5,081	9,795
Loans, net	4,636,219	4,532,364
FHLB of Dallas stock and other restricted stock	26,672	26,536
Accrued interest receivable	11,410	12,331
Financial liabilities:
Deposits	4,726,879	4,581,866
Accrued interest payable	2,398	4,020
FHLB advances	469,430	459,436
Other borrowings	110,550	110,000
Junior subordinated debentures	18,140	18,131
Estimated Fair Value | Commitments to extend credit
Off-balance sheet assets (liabilities):
Financial instruments with off-balance sheet risk	0	0
Estimated Fair Value | Standby letters of credit
Off-balance sheet assets (liabilities):
Financial instruments with off-balance sheet risk	$ 0	$ 0

Stock Awards and Stock Warran55

Stock Awards and Stock Warrants - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested during the period (shares)	65,668	44,220
Compensation expense	$ 970	$ 1,220
Estimated future compensation expense	$ 8,015
Period for recognition	2 years 9 months 4 days
Fair value of common stock awards vested	$ 4,119	1,306
AOCI income tax effect from share-based compensation, net		$ (83)
Warrants outstanding (shares)	147,341
Purchase price of common stock, per share (usd per share)	$ 17.19
Number of warrants exercised (shares)	3,203
2013 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (shares)	800,000
2012 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock vesting period			5 years
Vested during the period (shares)	11,040
Minimum | 2013 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock vesting period	3 years
Maximum | 2013 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock vesting period	5 years
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee service share-based compensation, tax benefit from compensation expense	$ 724

Stock Awards and Stock Warran56

Stock Awards and Stock Warrants - Nonvested Shares Activity (Details) - $ / shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Number of Shares
Nonvested shares, beginning balance (shares)	280,524	373,572
Granted during the period (shares)	40,627	66,220
Vested during the period (shares)	(65,668)	(44,220)
Forfeited during the period (shares)	0	(6,334)
Nonvested shares, ending balance (shares)	255,483	389,238
Weighted Average Grant Date Fair Value
Nonvested shares, beginning balance (usd per share)	$ 36.88	$ 40.29
Granted during the period (usd per share)	62.37	29.91
Vested during the period (usd per share)	31.23	32.61
Forfeited during the period (usd per share)	0	42.25
Nonvested shares, ending balance (usd per share)	$ 42.38	$ 39.20

Stock Awards and Stock Warran57

Stock Awards and Stock Warrants - Future Vesting Schedule of Nonvested Shares (Details)	Mar. 31, 2017shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested shares (shares)	255,483
First year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested shares (shares)	124,575
Second year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested shares (shares)	79,482
Third year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested shares (shares)	41,526
Fourth year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested shares (shares)	6,050
Fifth year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested shares (shares)	3,850

Regulatory Matters - Additional

Regulatory Matters - Additional Information (Details)	Jan. 01, 2016
Regulated Operations [Abstract]
Capital required for capital adequacy ratio, capital conservation buffer (percent)	0.625%
Capital required for capital adequacy ratio, capital conservation buffer, annual increase (percent)	0.625%
Capital required for capital adequacy ratio, capital conservation buffer, maximum (percent)	2.50%

Regulatory Matters - Actual Cap

Regulatory Matters - Actual Capital Amounts and Ratios (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Consolidated
Total capital to risk weighted assets:
Actual Amount	$ 583,864	$ 568,808
Actual Ratio (percent)	11.44%	11.38%
Minimum Required for Capital Adequacy Purposes Amount	$ 408,474	$ 399,698
Minimum Required for Capital Adequacy Purposes Ratio (percent)	8.00%	8.00%
Tier 1 capital to risk weighted assets:
Actual Amount	$ 440,433	$ 427,217
Actual Ratio (percent)	8.63%	8.55%
Minimum Required for Capital Adequacy Purposes Amount	$ 306,356	$ 299,774
Minimum Required for Capital Adequacy Purposes Ratio (percent)	6.00%	6.00%
Common equity tier 1 to risk weighted assets
Actual Amount	$ 422,833	$ 409,617
Actual Ratio (percent)	8.28%	8.20%
Minimum Required for Capital Adequacy Purposes Amount	$ 229,767	$ 224,830
Minimum Required for Capital Adequacy Purposes Ratio (percent)	4.50%	4.50%
Tier 1 capital to average assets:
Actual Amount	$ 440,433	$ 427,217
Actual Ratio (percent)	7.84%	7.82%
Minimum Required for Capital Adequacy Purposes Amount	$ 224,601	$ 218,612
Minimum Required for Capital Adequacy Purposes Ratio (percent)	4.00%	4.00%
Bank
Total capital to risk weighted assets:
Actual Amount	$ 572,757	$ 558,551
Actual Ratio (percent)	11.22%	11.19%
Minimum Required for Capital Adequacy Purposes Amount	$ 408,247	$ 399,497
Minimum Required for Capital Adequacy Purposes Ratio (percent)	8.00%	8.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 510,309	$ 499,371
To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (percent)	10.00%	10.00%
Tier 1 capital to risk weighted assets:
Actual Amount	$ 539,326	$ 526,960
Actual Ratio (percent)	10.57%	10.55%
Minimum Required for Capital Adequacy Purposes Amount	$ 306,185	$ 299,623
Minimum Required for Capital Adequacy Purposes Ratio (percent)	6.00%	6.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 408,247	$ 399,497
To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (percent)	8.00%	8.00%
Common equity tier 1 to risk weighted assets
Actual Amount	$ 539,326	$ 526,960
Actual Ratio (percent)	10.57%	10.55%
Minimum Required for Capital Adequacy Purposes Amount	$ 229,639	$ 224,717
Minimum Required for Capital Adequacy Purposes Ratio (percent)	4.50%	4.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 331,701	$ 324,591
To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (percent)	6.50%	6.50%
Tier 1 capital to average assets:
Actual Amount	$ 539,326	$ 526,960
Actual Ratio (percent)	9.61%	9.65%
Minimum Required for Capital Adequacy Purposes Amount	$ 224,491	$ 218,517
Minimum Required for Capital Adequacy Purposes Ratio (percent)	4.00%	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 280,614	$ 273,146
To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (percent)	5.00%	5.00%

Subsequent Event - Narrative (D

Subsequent Event - Narrative (Details) $ / shares in Units, $ in Thousands	Apr. 26, 2017$ / shares	Apr. 01, 2017USD ($)branchshares	Mar. 31, 2017USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)
Subsequent Event [Line Items]
Goodwill			$ 258,319		$ 258,319
Acquisition expense			146	$ 639
Net income			15,671	12,452
Subsequent event
Subsequent Event [Line Items]
Dividends declared (per share) | $ / shares	$ 0.10
CBI
Subsequent Event [Line Items]
Acquisition expense			146		659
Pro forma net income			23,763	17,985	69,391
Pro forma revenue			88,564	84,853	350,067
CBI | Subsequent event
Subsequent Event [Line Items]
Business acquisition, percentage of outstanding stock acquired		100.00%
Stock issued (in shares) | shares		8,804,699
Cash paid		$ 17,463
Goodwill		$ 362,922
Acquisition-related Costs
Subsequent Event [Line Items]
Net income			$ (16,339)	$ 0	$ (659)
DFW Metroplex and Austin | CBI | Subsequent event
Subsequent Event [Line Items]
Number branches acquired | branch		24
Colorado | CBI | Subsequent event
Subsequent Event [Line Items]
Number branches acquired | branch		18

Subsequent Event - Schedule of

Subsequent Event - Schedule of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ / shares in Units, $ in Thousands	Apr. 01, 2017	Mar. 31, 2017	Dec. 31, 2016
Assets of acquired bank:
Goodwill		$ 258,319	$ 258,319
Subsequent event | CBI
Assets of acquired bank:
Cash and cash equivalents	$ 159,469
Securities available for sale	336,506
Loans	1,396,169
Premises and equipment	63,581
Other real estate owned	10,666
Goodwill	362,922
Core deposit intangible	15,623
Other assets	92,696
Total assets acquired	2,437,632
Liabilities of acquired bank:
Deposits	1,834,655
Junior subordinated debentures	12,566
Other liabilities	20,893
Total liabilities assumed	1,868,114
Common stock issued at $62.70 per share	552,055
Cash paid	$ 17,463
Business acquisition, share price (usd per share)	$ 62.70