Spirit of Texas Bancshares (STXB) 10-Q 9 Aug 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Aug. 02, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Trading Symbol	STXB
Entity Registrant Name	Spirit of Texas Bancshares, Inc.
Entity Central Index Key	0001499453
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Common Stock, Shares Outstanding		15,794,282
Entity Shell Company	false
Entity File Number	001-38484
Entity Current Reporting Status	Yes
Entity Tax Identification Number	900499552
Entity Address, Address Line One	1836 Spirit of Texas Way
Entity Address, City or Town	Conroe
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77301
City Area Code	936
Local Phone Number	521-1836

CONSOLIDATED BALANCE SHEETS (Un

CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Assets:
Cash and due from banks		$ 26,150	$ 22,664
Interest-bearing deposits in other banks		137,008	66,351
Total cash and cash equivalents		163,158	89,015
Time deposits in other banks		1,225
Investment securities:
Available for sale securities, at fair value		171,058	179,461
Total investment securities		171,058	179,461
Loans held for sale		2,583	3,945
Loans:
Loans held for investment	[1]	1,409,338	1,092,940
Less: allowance for loan and lease losses		(6,277)	(6,286)
Loans, net		1,403,061	1,086,654
Premises and equipment, net		62,815	53,877
Accrued interest receivable		7,039	4,934
Other real estate owned and repossessed assets		1,324	782
Goodwill		43,889	18,253
Core deposit intangible		12,583	8,558
SBA servicing asset		3,570	3,965
Deferred tax asset, net		48	328
Bank-owned life insurance		15,432	7,401
Federal Home Loan Bank and other bank stock, at cost		6,190	5,304
Other assets		4,485	4,276
Total assets		1,898,460	1,466,753
Transaction accounts:
Noninterest-bearing		367,892	256,784
Interest-bearing		569,839	378,822
Total transaction accounts		937,731	635,606
Time deposits		632,873	547,042
Total deposits		1,570,604	1,182,648
Accrued interest payable		1,134	702
Short-term borrowings			12,500
Long-term borrowings		80,525	67,916
Other liabilities		2,087	4,191
Total liabilities		1,654,350	1,267,957
Commitments and contingencies (Note 13)
Stockholders' Equity:
Preferred stock, $1 par value; 5 million shares authorized; 0 shares issued and outstanding
Common stock, no par value; 50 million shares authorized; 13,790,332 and 12,103,753 shares issued and outstanding		204,974	169,939
Retained earnings		36,640	27,003
Accumulated other comprehensive income (loss)		2,496	1,854
Total stockholders' equity		244,110	198,796
Total liabilities and stockholders' equity		$ 1,898,460	$ 1,466,753
[1]	Balance includes $(8.1) million and $(4.9) million of deferred fees, cost, premium and discount as of June 30, 2019 and December 31, 2018, respectively.

CONSOLIDATED BALANCE SHEETS (_2

CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0	$ 0
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares, issued	13,790,332	12,103,753
Common stock, shares, outstanding	13,790,332	12,103,753

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Interest income:
Interest and fees on loans	$ 22,204	$ 13,078	$ 39,322	$ 25,369
Interest and dividends on investment securities	1,302	195	2,484	409
Other interest income	794	215	1,378	363
Total interest income	24,300	13,488	43,184	26,141
Interest expense:
Interest on deposits	3,938	1,941	7,009	3,672
Interest on FHLB advances and other borrowings	611	465	989	1,006
Total interest expense	4,549	2,406	7,998	4,678
Net interest income	19,751	11,082	35,186	21,463
Provision for loan losses	332	635	1,181	974
Net interest income after provision for loan losses	19,419	10,447	34,005	20,489
Noninterest income:
Service charges and fees	969	419	1,698	776
SBA loan servicing fees	40	548	304	1,172
Mortgage referral fees	198	208	308	364
Gain on sales of loans, net	1,384	1,041	2,188	2,515
Gain on sales of investment securities	1,053		2,134
Other noninterest income	131	87	200	64
Total noninterest income	3,775	2,303	6,832	4,891
Noninterest expense:
Salaries and employee benefits	8,765	6,043	15,889	12,901
Occupancy and equipment expenses	1,690	1,221	2,952	2,457
Professional services	1,022	314	2,063	625
Data processing and network	731	321	1,216	634
Regulatory assessments and insurance	315	266	413	521
Amortization of intangibles	1,006	175	1,609	351
Advertising	167	102	264	217
Marketing	132	121	271	239
Telephone expense	338	114	478	212
Conversion expense	453		1,604
Other operating expenses	1,206	704	2,070	1,350
Total noninterest expense	15,825	9,381	28,829	19,507
Income before income tax expense	7,369	3,369	12,008	5,873
Income tax expense	1,542	688	2,371	1,179
Net income	$ 5,827	$ 2,681	$ 9,637	$ 4,694
Earnings per common share:
Basic	$ 0.42	$ 0.30	$ 0.74	$ 0.58
Diluted	$ 0.41	$ 0.29	$ 0.72	$ 0.56
Weighted average common shares outstanding:
Basic	13,765,929	8,851,446	12,963,700	8,104,370
Diluted	14,236,244	9,306,029	13,432,760	8,445,960

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 5,827	$ 2,681	$ 9,637	$ 4,694
Other comprehensive income (loss):
Unrealized net holding gains (losses) on investment securities available for sale, net of (tax) and benefit of $(390), $17, $(699) and $153, respectively	1,468	(66)	2,630	(576)
Reclassification adjustment for realized (gains) losses on investment securities available for sale included in net income, net of taxes of $260, $0, $529 and $0, respectively	(976)		(1,988)
Total other comprehensive income (loss)	492	(66)	642	(576)
Total comprehensive income	$ 6,319	$ 2,615	$ 10,279	$ 4,118

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
Unrealized net holding gains (losses) on investment securities available for sale, (tax) and benefit	$ (390)	$ 17	$ (699)	$ 153
Reclassification adjustment for realized (gains) losses on investment securities available for sale included in net income, tax	$ 260	$ 0	$ 529	$ 0

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Balance at Dec. 31, 2017	$ 99,139	$ 82,615	$ 17,025	$ (501)
Balance (in shares) at Dec. 31, 2017		7,280,183
Net income	4,694		4,694
Shares issued in offering, net	42,219	$ 42,219
Shares issued in offering, net (in shares)		2,300,000
Exercise of stock options and warrants	2,185	$ 2,185
Exercise of stock options and warrants (in shares)		206,428
Stock-based compensation	325	$ 325
Other comprehensive income (loss)	(576)			(576)
Balance at Jun. 30, 2018	147,986	$ 127,344	21,719	(1,077)
Balance (in shares) at Jun. 30, 2018		9,786,611
Balance at Mar. 31, 2018	102,979	$ 84,952	19,038	(1,011)
Balance (in shares) at Mar. 31, 2018		7,486,611
Net income	2,681		2,681
Shares issued in offering, net	42,219	$ 42,219
Shares issued in offering, net (in shares)		2,300,000
Stock-based compensation	173	$ 173
Other comprehensive income (loss)	(66)			(66)
Balance at Jun. 30, 2018	147,986	$ 127,344	21,719	(1,077)
Balance (in shares) at Jun. 30, 2018		9,786,611
Balance at Dec. 31, 2018	198,796	$ 169,939	27,003	1,854
Balance (in shares) at Dec. 31, 2018		12,103,753
Net income	9,637		9,637
Shares issued in business combination	33,479	$ 33,479
Shares issued in business combination (in shares)		1,579,191
Exercise of stock options and warrants	1,288	$ 1,288
Exercise of stock options and warrants (in shares)		107,388
Stock-based compensation	268	$ 268
Other comprehensive income (loss)	642			642
Balance at Jun. 30, 2019	244,110	$ 204,974	36,640	2,496
Balance (in shares) at Jun. 30, 2019		13,790,332
Balance at Mar. 31, 2019	203,976	$ 171,159	30,813	2,004
Balance (in shares) at Mar. 31, 2019		12,195,891
Net income	5,827		5,827
Shares issued in business combination	33,479	$ 33,479
Shares issued in business combination (in shares)		1,579,191
Exercise of stock options and warrants	185	$ 185
Exercise of stock options and warrants (in shares)		15,250
Stock-based compensation	151	$ 151
Other comprehensive income (loss)	492			492
Balance at Jun. 30, 2019	$ 244,110	$ 204,974	$ 36,640	$ 2,496
Balance (in shares) at Jun. 30, 2019		13,790,332

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash Flows From Operating Activities:
Net income	$ 9,637	$ 4,694
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Provision for loan losses	1,181	974
Depreciation and amortization	1,353	945
Net amortization (accretion) of premium (discount) on investment securities	180	162
Amortization of core deposit intangible	1,609	351
Accretion of discount on retained SBA loans	(831)	(560)
Deferred tax expense (benefit)	269	17
Originations of loans held for sale	(24,774)	(34,082)
Proceeds from loans held for sale	28,422	32,740
Net gains on sale of loans held for sale	(2,188)	(2,515)
(Gain) loss on sale of investment securities	(2,134)
(Gain) loss on sale of other real estate owned	(53)	3
Fair value adjustment on SBA servicing asset	915	469
Stock-based compensation	268	325
Increase in cash surrender value of BOLI	(128)	(3)
Net change in operating assets and liabilities:
Net change in accrued interest receivable	(955)	271
Net change in accrued interest payable	92	24
Net change in other assets	811	544
Net change in other liabilities	(2,306)	(1,588)
Net cash provided by (used in) operating activities	11,368	2,771
Cash Flows From Investing Activities:
Purchases of investment securities available for sale	(32,536)
Sales of investment securities available for sale	79,920
Paydown and maturities of investment securities available for sale	21,135	1,833
Net purchase of FHLB and other bank stock	297	(18)
Proceeds from the sale of loans held for investment		1,451
Net change in loans	(21,042)	(50,816)
Proceeds from the sale of other real estate owned	884	18
Purchase of premises and equipment	(4,224)	(3,701)
Net cash received in business combination	28,565
Net cash provided by (used in) investing activities	72,999	(51,233)
Cash Flows From Financing Activities:
Net change in deposits	(11,698)	9,315
Redemption of trust preferred securities	77
Proceeds from long-term borrowings	23,174
Repayment of long-term borrowings	(10,565)	(10,220)
Proceeds from short-term borrowings		10,000
Repayment of short-term borrowings	(12,500)	(10,000)
Shares issued in offering, net		42,219
Exercise of stock options and warrants	1,288	2,185
Net cash provided by (used in) financing activities	(10,224)	43,499
Net Change in Cash and Cash Equivalents	74,143	(4,963)
Cash and Cash Equivalents at Beginning of Period	89,015	57,949
Cash and Cash Equivalents at End of Period	163,158	52,986
Supplemental Disclosures of Cash Flow Information:
Interest paid	7,264	3,648
Income taxes paid	1,000	2,050
Supplemental disclosure of noncash investing and financing activities:
Transfer of loans to other real estate owned and repossessed assets	15	$ 289
Fair value of assets acquired in business combination, excluding cash	405,561
Goodwill recorded	25,636
Liabilities assumed in business combination	400,197
Stock issued in business combination	$ 33,480

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	NOTE 1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Nature of Operations Spirit of Texas Bancshares, Inc. (the “Holding Company” or “Company”) is a bank holding company headquartered in Conroe, Texas that provides, through its bank subsidiary, a variety of financial services to individuals and corporate customers in Texas, which are primarily agricultural, light industrial and commercial areas. The Company consummated the underwritten initial public offering of its common stock in May 2018. In connection with the initial public offering, the Company issued and sold 2,300,000 shares of its common stock, including 300,000 shares of common stock sold pursuant to the underwriters’ full exercise of their option to purchase additional shares, at an offering price of $21.00 per share, for aggregate gross proceeds of $48.3 million before deducting underwriting discounts and offering expenses, and aggregate net proceeds of $42.1 million after deducting underwriting discounts and offering expenses. Basis of Presentation The consolidated financial statements include the accounts of the Holding Company and the accounts of its wholly-owned subsidiary, Spirit of Texas Bank SSB (the “Bank”). All significant intercompany balances and transactions have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and Article 8 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. Operating results for the period ended June 30, 2019 are not necessarily indicative of the results that may be expected for the year ending December 31, 2019 and should be read in conjunction with the audited financial statements and notes thereto for the year ended December 31, 2018 previously filed with the Securities and Exchange Commission (“SEC”) in the Company’s Annual Report on Form 10-K In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for the fair presentation of these consolidated financial statements have been included. The preparation of financial statements in conformity with these accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and income and expense during the reporting periods and the related disclosures. Although management’s estimates and assumptions are based on current expectations, estimates, forecasts and projections about future performance of the Company, such estimates and assumptions are not guarantees of future performance and involve certain risks, uncertainties and assumptions that are difficult for the Company to assess. Operating results for the interim periods disclosed herein are not necessarily indicative of the results that may be expected for a full year or any future period. Accounting Policies Recently Adopted and Pending Accounting Pronouncements Accounting Standards Update (ASU) 2019-04, “Codification Improvements to Topic 326, Financial Instruments-Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments” – issued in April 2019, ASU No. 2019-04 clarifies a number of issues discussed at the June 2018 and November 2018 Credit Losses Transition Resource Group meetings. The clarifications address a variety of identified issues including but not limited to the treatment of accrued interest receivable as it relates to the allowance for credit losses, transfers between loan classifications and categories, recoveries, and using projections of future interest rate environments in expected cash flow calculations. Management is evaluating these clarifications concurrently with our assessment of ASU 2016-13. ASU 2018-13, “Fair Value Measurement Disclosure Framework” – issued in August 2018, ASU No. 2018-13 modifies the disclosure requirements on fair value measurements outlined in Topic 820, Fair Value Measurements. Specifically the amendments in the ASU remove the requirements to disclose the amount and reasons for transfers between fair value hierarchy levels, the policy for timing of transfers between levels, the valuation processes for Level 3 fair value measurements, and for nonpublic entities, disclosure of the changes in unrealized gains and losses for the period included in earnings for recurring Level 3 fair value measurements. Additionally, the ASU adds disclosure requirements regarding changes in unrealized gains and losses for the period included in other comprehensive income related to Level 3 fair value measurements, and disclosure of the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. The amendments of ASU 2018-13 are effective for all entities for interim and annual periods beginning after December 15, 2019. Management adopted the provisions of this ASU removing fair value disclosure requirements as of December 31, 2018 as early adoption of the removal provisions was allowed and will adopt the remaining provisions of the ASU as of the effective date. ASU 2018-09, “Codification Improvements.” - issued in July 2018, ASU No. 2018-09 makes changes to a variety of topics to clarify, correct errors in, or make minor improvements to the Accounting Standards Codification. The majority of the amendments in ASU 2018-09 will be effective in annual periods beginning after December 15, 2018. ASU 2018-09 is not expected to have a material impact on the Company’s consolidated financial statements. ASU 2017-04, “Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment.” Issued in January 2017, ASU 2017-04 simplifies the manner in which an entity is required to test goodwill for impairment by eliminating Step 2 from the goodwill impairment test. Step 2 measures a goodwill impairment loss by comparing the implied fair value of a reporting unit’s goodwill with the carrying amount of that goodwill. In computing the implied fair value of goodwill under Step 2, an entity, prior to the amendments in ASU 2017-04, had to perform procedures to determine the fair value at the impairment testing date of its assets and liabilities, including unrecognized assets and liabilities, in accordance with the procedure that would be required in determining the fair value of assets acquired and liabilities assumed in a business combination. However, under the amendments in ASU 2017-04, an entity should (1) perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount, and (2) recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, with the understanding that the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Additionally, ASU 2017-04 removes the requirements for any reporting unit with a zero or negative carrying amount to perform a qualitative assessment and, if it fails such qualitative test, to perform Step 2 of the goodwill impairment test. ASU 2017-04 is effective prospectively for public entities for annual, or any interim, goodwill impairment tests in fiscal years beginning after December 15, 2019 and for all other entities for impairment tests in fiscal years beginning after December 15, 2021. Management will adopt this ASU using the public company effective date as early adoption is permitted and will continue to evaluate the impact this ASU will have on the consolidated financial statements through its effective date; however, the adoption of ASU 2017-04 is not expected to have a material impact on the Company’s consolidated financial statements. ASU 2016-13, “Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” Issued in June 2016, ASU 2016-13 will add FASB ASC Topic 326, “Financial Instruments-Credit Losses” and finalizes amendments to FASB ASC Subtopic 825-15, “Financial Instruments-Credit Losses.” The amendments of ASU 2016-13 are intended to provide financial statement users with more decision-useful information related to expected credit losses on financial instruments and other commitments to extend credit by replacing the current incurred loss impairment methodology with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to determine credit loss estimates. The amendments of ASU 2016-13 eliminate the probable initial recognition threshold and, in turn, reflect an entity’s current estimate of all expected credit losses. ASU 2016-13 does not specify the method for measuring expected credit losses, and an entity is allowed to apply methods that reasonably reflect its expectations of the credit loss estimate. Additionally, the amendments of ASU 2016-13 require that credit losses on available for sale debt securities be presented as an allowance rather than as a write-down. The amendments of ASU 2016-13 were originally effective for public entities for interim and annual periods beginning after December 15, 2019 and for all other entities for periods beginning after December 15, 2020. Issued in November 2018, ASU 2018-19 , alters the effective date of ASU 2016-13 for private companies. Under the provisions of ASU 2018-19, ASU 2016-13 is now effective for fiscal years beginning after December 15, 2021 including interim periods within those years for non-public business entities. Earlier application is permitted for interim and annual periods beginning after December 15, 2018. Management has elected to adopt this ASU using the updated private company effective date and is currently evaluating the impact this ASU will have on the consolidated financial statements and that evaluation will depend on economic conditions and the composition of the Company’s loan and lease portfolio at the time of adoption. ASU 2016-02, “Leases (Topic 842).” Issued in February 2016, ASU 2016-02 was issued by the FASB to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and by disclosing key information about leasing arrangements. ASU 2016-02 will, among other things, require lessees to recognize a lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. ASU 2016-02 does not significantly change lease accounting requirements applicable to lessors; however, the ASU contains some targeted improvements that are intended to align, where necessary, lessor accounting with the lessee accounting model and with the updated revenue recognition guidance issued in 2014. The amendments of ASU 2016-02 are effective for public entities for interim and annual periods beginning after December 15, 2018 and for other entities for periods beginning after December 15, 2019. The adoption of this ASU will result in an increase to the Consolidated Balance Sheets for right-of-use assets and associated lease liabilities for operating leases in which the Company is the lessee. Under current accounting standards, all of the Company's leases are classified as operating leases and, as such, are not recognized on the Company's Consolidated Balance Sheet. Additionally, in July 2018, the FASB issued ASU No. 2018-10, Codification Improvements to Topic 842, Leases and ASU No. 2018-11, Leases, Targeted Improvements. The amendments in these updates provide additional clarification and implementation guidance on certain aspects of ASU 2016-02 and have the same effective and transition requirements as ASU 2016-02. Specifically, ASU 2018-11 creates an additional transition method option allowing entities to record a cumulative effect adjustment to opening retained earnings in the year of adoption. In December 2018, the FASB further issued ASU 2018-20, Leases (Topic 842) Narrow-Scope Improvements for Lessors . The amendments in this update permits lessors to make an accounting policy election to not evaluate whether certain sales taxes and other similar taxes are lessor costs or lessee costs and instead account for the costs as if they were lessee costs. Additionally, the amendment requires lessors to exclude from variable payments, and therefore revenue, lessor costs paid by lessees directly to third parties. The amendments also require lessors to account for costs excluded from the consideration of a contract that are paid by the lessor and reimbursed by the lessee as variable payments. In March 2019, the FASB also issued ASU 2019-01, Leases (Topic 842) Codification Improvements, to further clarify certain identified issues regarding implementation of ASU 2016-02. Specifically, the amendments in ASU 2019-01 clarify the determination of fair value of underlying assets by lessors that are not manufacturers or dealers, the cash flow presentation of sales-type or direct financing leases, and transition disclosures for interim periods. Management will adopt these ASUs using the private company effective date of January 1, 2020 and is currently evaluating the impact to the consolidated financial statements and related method of adoption, specifically, we are in the process of determining an appropriate discount rate to record identified right-of-use assets.

Revenue Recognition

Revenue Recognition	6 Months Ended
	Jun. 30, 2019
Revenue From Contract With Customer [Abstract]
Revenue Recognition	NOTE 2. REVENUE RECOGNITION On January 1, 2019, the Company adopted ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) Topic 606 does not apply to revenue associated with financial instruments, including revenue from loans and securities. In addition, certain non-interest income streams such as fees associated with mortgage servicing rights, financial guarantees, derivatives, and certain credit card fees are also not in scope of the new guidance. Topic 606 is applicable to non-interest revenue streams, such as deposit related fees, interchange fees, merchant income, and brokerage and investment advisory service commissions. However, the recognition of these revenue streams did not change significantly upon adoption of Topic 606. Substantially all of the Company’s revenue is generated from contracts with customers. Non-interest revenue streams in-scope of Topic 606 are discussed below. Core Service Charges on Deposit Accounts Core service charges on deposit accounts consist of account analysis fees (i.e., net fees earned on analyzed business and public checking accounts) and monthly service fees. The Company’s performance obligation for account analysis fees and monthly service fees is generally satisfied, and the related revenue recognized, over the period in which the service is provided. Payment for service charges on deposit accounts is primarily received immediately or in the following month through a direct charge to customers’ accounts. Transaction Based Fee Income on Deposit Accounts Transaction based fee income on deposit accounts consists of variable revenue streams associated with activities which a deposit account holder may initiate on a transaction by transaction basis. The majority of transaction based fee income arises from interchange revenue received when deposit customers use a debit card for a point of sale transaction over a third party card payment network. Interchange revenue is recorded net of related interchange expenses in the month in which the transaction occurs. Merchant services income is realized through a third party service provider who is contracted by the Bank under a referral arrangement. Such fees represent fees charged to merchants to process their debit card transactions, in addition to account management fees. The third party service provider also issues credit cards as private label in the Company's name in exchange for a referral fee. Fees are earned and recorded in the same period as the referral occurs and the card is issued. Other transaction based service charges on deposit accounts include revenue from processing wire transfers, issuing cashier’s checks, processing check orders, and renting safe deposit boxes. The Company’s performance obligation related to these service charges is largely satisfied, and related revenue recognized, when the services are rendered or upon completion. Payment is typically received immediately or charged to the customers’ account in the period the service is provided. Safe deposit box rental fees are charged to the customer on an annual basis and recognized upon receipt of payment. The Company determined that since rentals and renewals occur fairly consistently over time, revenue is recognized on a basis consistent with the duration of the performance obligation. Mortgage Referral Fees Mortgage referral fees are also transaction based fee income. The Company’s performance obligation for fees is largely satisfied when the services are rendered or upon completion. Payment is typically received immediately. The following presents non-interest income, segregated by revenue streams in-scope and out-of-scope of Topic 606, for the three and six months ended June 30, 2019 and 2018: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Non-Interest Income In-scope of Topic 606 Deposit accounts core service charges $ 149 $ 78 $ 261 $ 145 Deposit account transaction based fee income 829 344 1,460 639 Mortgage referral fees 198 208 308 364 Non-Interest Income (in-scope of Topic 606) 1,176 630 2,029 1,148 Non-Interest Income (out-of-scope of Topic 606) 2,599 1,673 4,803 3,743 Total Non-Interest Income $ 3,775 $ 2,303 $ 6,832 $ 4,891 Contract Balances A contract asset balance occurs when an entity performs a service for a customer before the customer pays consideration (resulting in a contract receivable) or before payment is due (resulting in a contract asset). A contract liability balance is an entity’s obligation to transfer a service to a customer for which the entity has already received payment (or payment is due) from the customer. The Company’s non-interest revenue streams are largely based on transactional activity, or standard month-end revenue accruals. Consideration is often received immediately or shortly after the Company satisfies its performance obligation and revenue is recognized. The Company does not typically enter into long-term revenue contracts with customers, and therefore, does not experience significant contract balances. The Company did not have any significant contract balances at June 30, 2019 or December 31, 2018. Contract Acquisition Costs In connection with the adoption of Topic 606, an entity is required to capitalize, and subsequently amortize into expense, certain incremental costs of obtaining a contract with a customer if these costs are expected to be recovered. The incremental costs of obtaining a contract are those costs that an entity incurs to obtain a contract with a customer that it would not have incurred if the contract had not been obtained (for example, sales commission). The Company utilizes the practical expedient which allows entities to immediately expense contract acquisition costs when the asset that would have resulted from capitalizing these costs would have been amortized in one year or less. Upon adoption of Topic 606, the Company did not capitalize any contract acquisition cost.

Business Combinations

Business Combinations	6 Months Ended
	Jun. 30, 2019
Business Combinations [Abstract]
Business Combinations	NOTE 3. BUSINESS COMBINATIONS Comanche National Corporation On November 14, 2018, Spirit of Texas Bancshares, Inc. (the “Company” or “Spirit”) completed its acquisition of Comanche National Corporation and its subsidiary, The Comanche National Bank (together, “Comanche”). This transaction resulted in 8 additional branches in the North Texas region. The Company issued 2,142,811 shares of its common stock as well as a net cash payment to Comanche shareholders of $12.2 million, for a total consideration of $52.9 million, for all outstanding stock of Comanche and resulted in 100% ownership interest. The Company has recognized total goodwill of $13.8 million 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 fair value of the consideration exchanged related to the Company’s common stock was calculated based upon the closing market price of the Company’s common stock as of November 14, 2018. None of the goodwill recognized is expected to be deductible for income tax purposes. The Company did not incur any expenses related to the acquisition for the three months ended June, 30 2019 and incurred approximately $1.2 million for the six months ended June 30, 2019, which are included in noninterest expense in consolidated statements of income. The Company did not incur any expenses related to the acquisition during the three or six months ended June 30, 2018. Non-credit impaired loans had a fair value of $116.2 million at the acquisition date and contractual balance of $117.2 million. As of the acquisition date, the Company expects that an insignificant amount of the contractual balance of these loans will be uncollectible. The difference of $946 thousand will be recognized into interest income as an adjustment to yield over the life of the loans. Fair values of the assets acquired and liabilities assumed in this transaction as of the closing date are as follows: Assets of acquired bank (Dollars in thousands): Cash and cash equivalents $ 57,135 Securities available for sale 144,735 Loans held for investment 116,220 Premises and equipment, net 6,634 Other real estate owned 33 Goodwill 13,768 Core deposit intangible 5,988 Other assets 11,712 Total assets acquired $ 356,225 Liablilities of acquired bank: Deposits $ 297,778 Trust preferred securities 2,811 Other liabilities 2,698 Total liabilities assumed $ 303,287 Common stock issued at $18.99 per share $ 40,692 Cash paid $ 12,246 As of June 30, 2019, management has completed its evaluation of the fair values of other assets and other liabilities. Amounts shown above are considered finalized. Revenues and earnings of the acquired company since the acquisition date have not been disclosed as Comanche was merged into the Company and separate financial information is not readily available. First Beeville Financial Corporation On April 2, 2019 Spirit completed its acquisition of First Beeville Financial Corporation and its subsidiary, The First National Bank of Beeville (together, “Beeville”). This transaction resulted in three additional branches and two loan production offices in the South Texas region. The Company issued 1,579,191 shares of its common stock as well as a net cash payment to Beeville shareholders of $32.4 million, for a total consideration of $65.9 million, for all outstanding stock of Beeville and resulted in 100% ownership interest. The Company has recognized total goodwill of $25.6 million 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 fair value of the consideration exchanged related to the Company’s common stock was calculated based upon the closing market price of the Company’s common The Company incurred expenses related to the acquisition of approximately $1.2 million and $1.7 million for the three and six months ended June 30, 2019, respectively, which are included in noninterest expense in consolidated statements of income. The Company did not incur any expenses related to the acquisition during the three or six months ended June 30, 2018. Non-credit impaired loans had a fair value of $296.3 million at the acquisition date and contractual balance of $298.9 million. As of the acquisition date, the Company expects that an insignificant amount of the contractual balance of these loans will be uncollectible. The difference of $2.6 million will be recognized into interest income as an adjustment to yield over the life of the loans. 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 (Dollars in thousands): Cash and cash equivalents $ 60,941 Securities available for sale 57,206 Loans held for investment 296,348 Premises and equipment, net 6,067 Other real estate owned 1,359 Goodwill 25,636 Core deposit intangible 5,635 Other assets 12,860 Total assets acquired $ 466,052 Liabilities of acquired bank: Deposits $ 399,654 Other liabilities 543 Total liabilities assumed $ 400,197 Common stock issued at $21.20 per share $ 33,480 Cash paid $ 32,375 As of June 30, 2019, the purchase accounting adjustments associated with loans, time deposits, core deposit intangible, and deferred taxes were preliminary. Management is still evaluating the assumptions used in the fair value calculations and expects to finalize these values by the fourth quarter of 2019. For the three months ending June 30, 2019, revenues and earnings of the acquired company since the acquisition date were $5.2 million and $2.6 million respectively.

Investment Securities

Investment Securities	6 Months Ended
	Jun. 30, 2019
Investments Debt And Equity Securities [Abstract]
Investment Securities	NOTE 4. INVESTMENT SECURITIES The amortized cost, gross unrealized gains and losses and approximate fair values of securities available for sale are as follows: Amortized Unrealized Fair June 30, 2019 Cost Gains Losses Value (Dollars in thousands) Available for sale: U.S. Treasury securities $ 32,537 $ 3 $ 4 $ 32,536 U.S. Government agencies 4,084 37 - 4,121 State and municipal obligations 24,988 459 29 25,418 Residential mortgage-backed securities 102,151 2,306 1,154 103,303 Corporate bonds and other debt securities 5,645 38 3 5,680 Total available for sale $ 169,405 $ 2,843 $ 1,190 $ 171,058 Amortized Unrealized Fair December 31, 2018 Cost Gains Losses Value (Dollars in thousands) Available for sale: U.S. Government agencies $ 2,015 $ — $ 81 $ 1,934 State and municipal obligations 17,201 847 — 18,048 Residential mortgage-backed securities 152,232 2,614 872 153,974 Corporate bonds and other debt securities 5,667 — 162 5,505 Total available for sale $ 177,115 $ 3,461 $ 1,115 $ 179,461 Taxable interest and dividends on investment securities were $1.1 million and $195 thousand for the three months ended June 30, 2019 and 2018, respectively. Tax-exempt interest and dividends on investment securities were $163 thousand for the three months ended June 30, 2019. There were no tax-exempt interest or dividends on investment securities for the three months ended June 30, 2018. Taxable interest and dividends on investment securities were $2.2 million and $409 thousand for the six months ended June 30, 2019 and 2018, respectively. Tax-exempt interest and dividends on investment securities were $271 thousand for the six months ended June 30, 2019. There were no tax-exempt interest or dividends on investment securities for the six months ended June 30, 2018. There were $145.1 million and $106.6 million securities pledged to collateralize public funds at June 30, 2019 The amortized cost and estimated fair value of securities available for sale, by contractual maturity, are as follows: Amortized Fair June 30, 2019 Cost Value (Dollars in thousands) Available for sale: Due in one year or less $ 9,695 $ 9,690 Due after one year through five years 43,470 43,535 Due after five years through ten years 8,417 8,459 Due after ten years 5,672 6,071 Residential mortgage-backed securities 102,151 103,303 Total available for sale $ 169,405 $ 171,058 For purposes of the maturity table, residential mortgage-backed securities, the principal of which are repaid periodically, are presented as a single amount. The expected lives of these securities will differ from contractual maturities because borrowers may have the right to prepay the underlying loans with or without prepayment penalties. The following tables present the estimated fair values and gross unrealized losses on investment securities available for sale, aggregated by investment category and length of time individual securities have been in a continuous unrealized loss position as of the periods presented: Less than 12 Months 12 Months or More Total June 30, 2019 Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss (Dollars in thousands) Available for sale: U.S. Treasury securities $ 14,447 $ 4 $ - $ - $ 14,447 $ 4 U.S. Government agencies — — - - - - State and municipal obligations — — 11,014 29 11,014 29 Residential mortgage-backed securities — — 26,009 1,154 26,009 1,154 Corporate bonds and other debt securities — — 1,996 3 1,996 3 Total available for sale $ 14,447 $ 4 $ 39,019 $ 1,186 $ 53,466 $ 1,190 Less than 12 Months 12 Months or More Total December 31, 2018 Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss (Dollars in thousands) Available for sale: U.S. Government agencies $ — $ — $ 1,934 $ 81 $ 1,934 $ 81 State and municipal obligations — — — — — — Residential mortgage-backed securities 1 — 25,479 872 25,480 872 Corporate bonds and other debt securities — — 5,505 162 5,505 162 Total available for sale $ 1 $ — $ 32,918 $ 1,115 $ 32,919 $ 1,115 At June 30, 2019, the Company’s securities portfolio consisted of 229 securities, 69 of which were in an unrealized loss position. Sixty-four of the sixty-nine securities in an unrealized loss position at June 30, 2019 were in an unrealized loss position for more than 12 months. The unrealized losses for these securities resulted primarily from changes in interest rates and spreads. The Company monitors its investment securities for other-than-temporary-impairment (“OTTI”). Impairment is evaluated on an individual security basis considering numerous factors, and its relative significance. The Company has evaluated the nature of unrealized losses in the investment securities portfolio to determine if OTTI exists. The unrealized losses relate to changes in market interest rates and specific market conditions that do not represent credit-related impairments. Furthermore, the Company does not intend to sell nor is it more likely than not that it will be required to sell these investments before the recovery of their amortized cost basis. Management has completed an assessment of each security in an unrealized loss position for credit impairment and has determined that no individual security was other-than-temporarily impaired at June 30, 2019. The following describes the basis under which the Company has evaluated OTTI: U.S. Treasury Securities, U.S. Government Agencies and Residential Mortgage-Backed Securities (“MBS”): The unrealized losses associated with U.S. Treasury securities, U.S. Government agencies and residential MBS are primarily driven by changes in interest rates. These securities have either an explicit or implicit U.S. government guarantee. Corporate Bonds & Other Debt Securities: Securities are generally underwritten in accordance with the Company’s investment standards prior to the decision to purchase, without relying on a bond issuer’s guarantee in making the investment decision. These investments are investment grade and will continue to be monitored as part of the Company’s ongoing impairment analysis, but are expected to perform in accordance with their terms. Sale proceeds from the sale of available for sale securities for the three and six months ended June 30, 2019 were $34.7 million and $79.9 million which resulted in gross realized gains of $1.1 million and $2.1 million, respectively. There were no securities sold for the three or six months ended June 30, 2018.

Loans, Net

Loans, Net	6 Months Ended
	Jun. 30, 2019
Receivables [Abstract]
Loans, Net	NOTE 5. LOANS, NET Loans consisted of the following at June 30, 2019 and December 31, 2018: June 30, 2019 December 31, 2018 (Dollars in thousands) Commercial and industrial loans (1) $ 197,774 $ 173,892 Real estate: 1-4 single family residential loans 277,560 275,644 Construction, land and development 176,567 159,734 Commercial real estate loans (including multifamily) 666,981 397,953 Consumer loans and leases 20,745 24,378 Municipal and other loans 69,711 61,339 Total loans held in portfolio (2) $ 1,409,338 $ 1,092,940 Allowance for loan losses (6,277 ) (6,286 ) Loans held in portfolio, net $ 1,403,061 $ 1,086,654 (1) Balance includes $71.3 million and $76.9 million of the unguaranteed portion of SBA loans as of June 30, 2019 and December 31, 2018, respectively. (2) Balance includes $(8.1) million and $(4.9) million of deferred fees, cost, premium and discount as of June 30, 2019 and December 31, 2018, respectively. At June 30, 2019 and December 31, 2018, the Company had pledged loans as collateral for FHLB advances of $516.4 million and $385.5 million, respectively. There were no recorded investments of consumer mortgage loans secured by residential real estate properties for which formal foreclosure proceedings are in process as of June 30, 2019 and December 31, 2018. The Company originates and sells loans secured by the SBA. The Company retains the unguaranteed portion of the loan and servicing on the loans sold and receives a fee based upon the principal balance outstanding. During the three months ended June 30, 2019 and 2018, the Company sold approximately $16.4 million and $12.9 million, respectively, in loans to third parties. The loan sales resulted in realized gains of $1.4 million and $1.0 million for the three months ended June 30, 2019 and 2018, respectively. During the six months ended June 30, 2019 and 2018, the Company sold approximately $26.5 and $30.0 million, respectively, in loans to third parties. The loan sales resulted in realized gains of $2.2 million and $2.5 million for the six months ended June 30, 2019 and 2018, respectively. In the ordinary course of business, the Company makes loans to executive officers and directors. Loans to these related parties, including companies in which they are principal owners, are as follows: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (Dollars in thousands) Principal outstanding, beginning of year $ 93 $ 442 $ 107 $ 463 Additions (reductions) of affiliations 2,352 — 2,352 — New loans made in current year — — — — Repayments (12 ) (21 ) (26 ) (42 ) Principal outstanding, end of year $ 2,433 $ 421 $ 2,433 $ 421 There were no unfunded commitments to related parties at June 30, 2019 or December 31, 2018.

Allowance for Loan and Lease Lo

Allowance for Loan and Lease Losses	6 Months Ended
	Jun. 30, 2019
Receivables [Abstract]
Allowance for Loan and Lease Losses	NOTE 6. ALLOWANCE FOR LOAN AND LEASE LOSSES The allowance for loan and lease losses is a reserve established through a provision for loan losses charged to expense, which represents management’s best estimate of probable losses that have been incurred within the existing portfolio of loans. The allowance, in the judgment of management, is necessary to reserve for estimated loan losses and risks inherent in the loan portfolio. The methodology is based on historical loss experience by type of credit and internal risk grade, changes in the composition and volume of the portfolio, and specific loss allocations, with adjustments for current events and conditions. The Company’s process for determining the appropriate level of the allowance for loan and lease losses is designated to account for credit deterioration as it occurs. Prior to the second quarter of 2018, the Company was utilizing a peer bank allowance coverage ratio in the qualitative reserve calculation, as the Company did not have enough historical defaults to rely on its own loss factors. Beginning the second quarter of 2018, the Company had a sufficient amount of defaults over the five year lookback period to transition over to relying more on its own historical loss data versus peer data. While this did not result in a significant change to the allowance for loan and lease losses as a whole, it continues to impact the provision for certain loan categories in which the Company had experienced more historical defaults. On November 14, 2018, the Company closed its acquisition of Comanche. At the date of acquisition, Comanche had $117.2 million in loans. In accordance with ASC 805 Business Combinations, the Company utilized a third party to value the loan portfolio as of the acquisition date. Based upon the third party valuation, the fair value of the loans was approximately $116.2 million at the acquisition date. The overall discount calculated was $946 thousand and will be accreted into interest income over the life of the loans. On April 2, 2019, the Company closed its acquisition of Beeville. At the date of acquisition, Beeville had $298.9 million in loans. In accordance with ASC 805 Business Combinations, the Company utilized a third party to value the loan portfolio as of the acquisition date. Based upon the third party valuation, the fair value of the loans was approximately $296.3 million at the acquisition date. The overall discount calculated was $2.6 million and will be accreted into interest income over the life of the loans. As of June 30, 2019, all purchased loans were excluded from the allowance for loan and lease losses calculation given there was no deterioration between the acquisition date and the end of the second quarter of 2019. Purchased credit impaired loans were insignificant. Going forward, management will evaluate the remaining credit quality, credit discount and charge-offs associated with these purchased loans to determine if an additional allowance is deemed necessary. The following tables present information related to allowance for loan and lease losses for the periods presented: Allowance Rollforward Three Months Ended June 30, 2019 Beginning Balance Charge-offs Recoveries Provision Ending Balance (Dollars in thousands) Commercial and industrial loans $ 4,661 $ (643 ) $ 31 $ 168 $ 4,217 Real estate: 1-4 single family residential loans 34 — — (2 ) 32 Construction, land and development loans 749 — — 45 794 Commercial real estate loans (including multifamily) 1,057 — — 134 1,191 Consumer loans and leases 57 (16 ) 3 (9 ) 35 Municipal and other loans 11 — 1 (4 ) 8 Ending allowance balance $ 6,569 $ (659 ) $ 35 $ 332 $ 6,277 Allowance Rollforward Three Months Ended June 30, 2018 Beginning Balance Charge-offs Recoveries Provision Ending Balance (Dollars in thousands) Commercial and industrial loans $ 2,906 $ (321 ) $ 3 $ 2,298 $ 4,886 Real estate: 1-4 single family residential loans 887 (5 ) — (564 ) 318 Construction, land and development loans 540 — — (345 ) 195 Commercial real estate loans (including multifamily) 1,032 — — (799 ) 233 Consumer loans and leases 175 (24 ) — 195 346 Municipal and other loans 187 — — (150 ) 37 Ending allowance balance $ 5,727 $ (350 ) $ 3 $ 635 $ 6,015 Allowance Rollforward Six Months Ended June 30, 2019 Beginning Balance Charge-offs Recoveries Provision Ending Balance (Dollars in thousands) Commercial and industrial loans $ 4,453 $ (1,221 ) $ 59 $ 926 $ 4,217 Real estate: 1-4 single family residential loans 59 — — (27 ) 32 Construction, land and development loans 731 — — 63 794 Commercial real estate loans (including multifamily) 960 — — 231 1,191 Consumer loans and leases 80 (34 ) 5 (16 ) 35 Municipal and other loans 3 — 1 4 8 Ending allowance balance $ 6,286 $ (1,255 ) $ 65 $ 1,181 $ 6,277 Allowance Rollforward Six Months Ended June 30, 2018 Beginning Balance Charge-offs Recoveries Provision Ending Balance (Dollars in thousands) Commercial and industrial loans $ 3,046 $ (645 ) $ 69 $ 2,416 $ 4,886 Real estate: 1-4 single family residential loans 902 (5 ) — (579 ) 318 Construction, land and development loans 441 — — (246 ) 195 Commercial real estate loans (including multifamily) 898 — — (665 ) 233 Consumer loans and leases 198 (30 ) — 178 346 Municipal and other loans 167 — — (130 ) 37 Ending allowance balance $ 5,652 $ (680 ) $ 69 $ 974 $ 6,015 Credit Quality Indicators In evaluating credit risk, the Company looks at multiple factors; however, management considers delinquency status to be the most meaningful indicator of the credit quality of 1-4 single family residential, home equity loans and lines of credit and consumer loans. Delinquency statistics are updated at least monthly. Internal risk ratings are considered the most meaningful indicator of credit quality for commercial, construction, land and development and commercial real estate loans. Internal risk ratings are updated on a continuous basis. The following tables present an aging analysis of the recorded investment for delinquent loans by portfolio and segment: Accruing June 30, 2019 Current 30 to 59 Days Past Due 60 to 89 Days Past Due 90 Days or More Past Due Non- Accrual Total (Dollars in thousands) Commercial and industrial loans $ 192,098 $ 332 $ 62 $ — $ 5,282 $ 197,774 Real estate: 1-4 single family residential loans 277,004 303 45 — 208 277,560 Construction, land and development 174,373 2,194 — — — 176,567 Commercial real estate loans (including multifamily) 665,764 13 1,068 — 136 666,981 Consumer loans and leases 20,495 157 47 — 46 20,745 Municipal and other loans 69,576 — 82 — 53 69,711 Total loans $ 1,399,310 $ 2,999 $ 1,304 $ — $ 5,725 $ 1,409,338 Accruing December 31, 2018 Current 30 to 59 Days Past Due 60 to 89 Days Past Due 90 Days or More Past Due Non- Accrual Total (Dollars in thousands) Commercial and industrial loans $ 169,206 $ 605 $ 223 $ 288 $ 3,570 $ 173,892 Real estate: 1-4 single family residential loans 273,909 581 64 — 1,090 275,644 Construction, land and development 159,723 11 — — — 159,734 Commercial real estate loans (including multifamily) 396,559 451 589 — 354 397,953 Consumer loans and leases 24,109 208 44 — 17 24,378 Municipal and other loans 61,289 50 — — — 61,339 Total loans $ 1,084,795 $ 1,906 $ 920 $ 288 $ 5,031 $ 1,092,940 There were no loans 90 days or more past due and still accruing at June 30, 2019. There were four loans 90 days or more past due and still accruing at December 31, 2018 with a recorded investment of $288 thousand. At June 30, 2019, non-accrual loans that were 30 to 59 days past due were $38 thousand, non-accrual loans that were 60 to 89 days past due were $59 thousand, and non-accrual loans that were 90 days or more past due were $1.7 million. At December 31, 2018, non-accrual loans that were 30 to 59 days past due were $175 thousand, non-accrual loans that were 60 to 89 days past due were $143 thousand, and non-accrual loans that were 90 days or more past due were $2.0 million. Loans exhibiting potential credit weaknesses that deserve management’s close attention and that if left uncorrected may result in deterioration of the repayment capacity of the borrower are categorized as special mention. Loans with well-defined credit weaknesses including payment defaults, declining collateral values, frequent overdrafts, operating losses, increasing balance sheet leverage, inadequate cash flow, project cost overruns, unreasonable construction delays, past due real estate taxes or exhausted interest reserves are assigned an internal risk rating of substandard. Loans classified as substandard can be on an accrual or non-accrual basis, as determined by its unique characteristics. A loan with a weakness so severe that collection in full is highly questionable or improbable will be assigned an internal risk rating of doubtful. The following table summarizes the Company’s loans by key indicators of credit quality: June 30, 2019 Pass Special Mention Substandard Doubtful (Dollars in thousands) Commercial and industrial loans $ 191,854 $ 2,812 $ 3,108 $ — Real estate: 1-4 single family residential loans 276,076 951 533 — Construction, land and development 175,610 10 947 — Commercial real estate loans (including multifamily) 660,606 3,214 3,161 — Consumer loans and leases 20,734 — 11 — Municipal and other loans 69,711 — — — Total loans $ 1,394,591 $ 6,987 $ 7,760 $ — December 31, 2018 Pass Special Mention Substandard Doubtful (Dollars in thousands) Commercial and industrial loans $ 163,908 $ 3,170 $ 6,601 $ 213 Real estate: 1-4 single family residential loans 270,839 1,714 2,547 544 Construction, land and development 157,688 24 2,022 — Commercial real estate loans (including multifamily) 383,323 12,412 1,806 412 Consumer loans and leases 20,798 1,836 180 1,564 Municipal and other loans 60,837 484 — 18 Total loans $ 1,057,393 $ 19,640 $ 13,156 $ 2,751 Internal risk ratings and other credit metrics are key factors in identifying loans to be individually evaluated for impairment and impact management’s estimates of loss factors used in determining the amount of the allowance for loan and lease losses. The following table shows the Company’s investment in loans disaggregated based on the method of evaluating impairment: Loans - Recorded Investment Allowance for Credit Loss June 30, 2019 Individually Evaluated for Impairment Collectively Evaluated for Impairment Individually Evaluated for Impairment Collectively Evaluated for Impairment (Dollars in thousands) Commercial and industrial loans $ 3,783 $ 193,991 $ 1,618 $ 2,599 Real estate: 1-4 single family residential loans 1,401 276,159 4 28 Construction, land and development 219 176,348 — 794 Commercial real estate loans (including multifamily) 241 666,740 — 1,191 Consumer loans and leases 16 20,729 4 31 Municipal and other loans — 69,711 — 8 Total loans $ 5,660 $ 1,403,678 $ 1,626 $ 4,651 Loans - Recorded Investment Allowance for Credit Loss December 31, 2018 Individually Evaluated for Impairment Collectively Evaluated for Impairment Individually Evaluated for Impairment Collectively Evaluated for Impairment (Dollars in thousands) Commercial and industrial loans $ 3,640 $ 170,252 $ 1,234 $ 3,219 Real estate: 1-4 single family residential loans 1,193 274,451 29 30 Construction, land and development — 159,734 — 731 Commercial real estate loans (including multifamily) — 397,953 — 960 Consumer loans and leases 17 24,361 4 76 Municipal and other loans — 61,339 — 3 Total loans $ 4,850 $ 1,088,090 $ 1,267 $ 5,019 The following tables set forth certain information regarding the Company’s impaired loans that were evaluated for specific reserves: Impaired Loans - With Allowance Impaired Loans - With no Allowance June 30, 2019 Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance (Dollars in thousands) Commercial and industrial loans $ 3,124 $ 6,490 $ 1,618 $ 659 $ 3,170 Real estate: 1-4 single family residential loans 152 160 4 1,249 1,582 Construction, land and development — — — 219 223 Commercial real estate loans (including multifamily) — — — 241 246 Consumer loans and leases 16 16 4 — — Municipal and other loans — — — — — Total loans $ 3,292 $ 6,666 $ 1,626 $ 2,368 $ 5,221 Impaired Loans - With Allowance Impaired Loans - With no Allowance December 31, 2018 Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance (Dollars in thousands) Commercial and industrial loans $ 1,843 $ 5,392 $ 1,234 $ 1,797 $ 3,500 Real estate: 1-4 single family residential loans 116 124 29 1,077 1,086 Construction, land and development — — — — — Commercial real estate loans (including multifamily) — — — — — Consumer loans and leases 17 17 4 — — Municipal and other loans — — — — — Total loans $ 1,976 $ 5,533 $ 1,267 $ 2,874 $ 4,586 Three Months Ended June 30, 2019 2018 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized (Dollars in thousands) Commercial and industrial loans $ 3,691 $ — $ 2,435 $ — Real estate: 1-4 single family residential loans 1,282 — 1,511 — Construction, land and development 220 — 24 — Commercial real estate loans (including multifamily) 243 — 149 — Consumer loans and leases 16 — 101 — Municipal and other loans — — — — Total loans $ 5,452 $ — $ 4,220 $ — Six Months Ended June 30, 2019 2018 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized (Dollars in thousands) Commercial and industrial loans $ 3,797 $ — $ 2,620 $ — Real estate: 1-4 single family residential loans 1,295 — 1,518 — Construction, land and development 222 — 25 — Commercial real estate loans (including multifamily) 245 — 151 — Consumer loans and leases 17 — 103 — Municipal and other loans — — — — Total loans $ 5,576 $ — $ 4,417 $ — Troubled Debt Restructurings: The following table provides a summary of troubled debt restructurings (“TDRs”) based upon delinquency status, all of which are considered impaired: June 30, 2019 December 31, 2018 Number of contracts Recorded Investment Number of contracts Recorded Investment (Dollars in thousands) Performing TDRs: Commercial and industrial loans 3 $ 122 3 $ 69 Real estate: 1-4 single family residential loans 2 132 2 141 Construction, land and development — — — — Commercial real estate loans (including multifamily) — — — — Consumer loans and leases — — — — Municipal and other loans — — — — Total performing TDRs 5 254 5 210 Nonperforming TDRs 9 455 7 448 Total TDRs 14 $ 709 12 $ 658 Allowance attributable to TDRs $ 224 $ 149 The following table summarizes TDRs and includes newly designated TDRs as well as modifications made to existing TDRs. Modifications may include, but are not limited to, granting a material extension of time, entering into a forbearance agreement, adjusting the interest rate, accepting interest only payments for an extended period of time, a change in the amortization period or a combination of any of these. Post-modification balances represent the recorded investment at the end of Day 2 in which the modification was made: Three Months Ended June 30, 2019 2018 Number of Contracts Pre- Modification Outstanding Recorded Investment Post- Modification Outstanding Recorded Investment Related Allowance Number of Contracts Pre- Modification Outstanding Recorded Investment Post- Modification Outstanding Recorded Investment Related Allowance (Dollars in thousands) Commercial and industrial loans 3 $ 185 $ 185 $ 88 2 $ 73 $ 73 $ 53 Real estate: 1-4 single family residential loans — — — — 1 34 34 — Construction, land and development — — — — — — — — Commercial real estate loans (including multifamily) — — — — — — — — Consumer loans and leases — — — — — — — — Municipal and other loans — — — — — — — — Six Months Ended June 30, 2019 2018 Number of Contracts Pre- Modification Outstanding Recorded Investment Post- Modification Outstanding Recorded Investment Related Allowance Number of Contracts Pre- Modification Outstanding Recorded Investment Post- Modification Outstanding Recorded Investment Related Allowance (Dollars in thousands) Commercial and industrial loans 3 $ 185 $ 185 $ 88 7 $ 442 $ 442 $ 192 Real estate: 1-4 single family residential loans — — — — 1 34 34 — Construction, land and development — — — — — — — — Commercial real estate loans (including multifamily) — — — — — — — — Consumer loans and leases — — — — — — — — Municipal and other loans — — — — — — — — There have been no defaults of troubled debt restructurings that took place within the three or six months ended June 30, 2019 and 2018.

Goodwill and Intangibles

Goodwill and Intangibles	6 Months Ended
	Jun. 30, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangibles	NOTE 7. GOODWILL AND INTANGIBLES Goodwill and other intangible assets, which consist of core deposit intangibles, are summarized as follows: Six Months Ended June 30, 2019 Year Ended December 31, 2018 (Dollars in thousands) Beginning goodwill $ 18,253 $ 4,485 Arising from business combination 25,636 13,768 Ending goodwill $ 43,889 $ 18,253 Core deposit intangible 8,558 13,166 Arising from business combination 10,244 — Less: Accumulated amortization (6,219 ) (4,608 ) Core deposit intangible, net $ 12,583 $ 8,558 Amortization expense for core deposit intangibles for the three months ended June 30, 2019 and 2018 totaled $1.0 million and $175 thousand, respectively. Amortization expense for the core deposit intangibles for the six months ended June 30, 2019 and 2018 totaled $1.6 million and $351 thousand, respectively. The estimated amount of amortization expense for core deposit intangible assets to be recognized over the next five fiscal years is as follows: Type of intangibles Remainder of 2019 2020 2021 2022 2023 2024 (Dollars in thousands) Core deposit intangible $ 1,977 $ 3,503 $ 2,852 $ 2,063 $ 1,378 $ 649

SBA Servicing Asset

SBA Servicing Asset	6 Months Ended
	Jun. 30, 2019
Transfers And Servicing Of Financial Assets [Abstract]
SBA Servicing Asset	NOTE 8. SBA SERVICING ASSET SBA servicing assets are recognized separately when rights are acquired through the sale of the guaranteed portion of SBA loans. These servicing rights are initially measured at fair value at the date of sale and included in the gain on sale. Updated fair values are obtained from an independent third party on a quarterly basis and adjustments are presented in SBA loan servicing fees on the consolidated statements of income. To determine the fair value of SBA servicing rights, the Company uses market prices for comparable servicing contracts, when available, or alternatively, uses a valuation model that calculates the present value of estimated future net servicing income. Loans serviced for others are not included in the accompanying balance sheets. The unpaid principal balances of loans serviced for others were $213.5 million and $225.0 million at June 30, 2019 and December 31, 2018, respectively. SBA loan servicing fees were $40 thousand and $548 thousand for the three months ended June 30, 2019 and 2018, respectively. SBA loan servicing fees were $304 thousand and $1.2 million for the six months ended June 30, 2019 and 2018, respectively. The risks inherent in the SBA servicing asset relate primarily to changes in prepayments that result from shifts in interest rates. The following summarizes the activity pertaining to SBA servicing rights, which are in the consolidated balance sheets, for the three and six months ended June 30, 2019 and 2018: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (Dollars in thousands) Beginning balance $ 3,747 $ 3,512 $ 3,965 $ 3,411 Origination of servicing assets 322 247 520 579 Change in fair value: Due to run-off (239 ) (245 ) (404 ) (453 ) Due to market changes (260 ) 7 (511 ) (16 ) Ending balance $ 3,570 $ 3,521 $ 3,570 $ 3,521

Deposits

Deposits	6 Months Ended
	Jun. 30, 2019
Banking And Thrift [Abstract]
Deposits	NOTE 9. DEPOSITS The following table sets forth the Company’s deposits by category: June 30, 2019 December 31, 2018 (Dollars in thousands) Noninterest-bearing demand deposits $ 367,892 $ 256,784 Interest-bearing demand deposits 292,550 124,933 Interest-bearing NOW accounts 7,638 7,961 Savings and money market accounts 269,651 245,928 Time deposits 632,873 547,042 Total deposits $ 1,570,604 $ 1,182,648 Time deposits $100,000 and greater $ 500,044 $ 422,447 Time deposits $250,000 and greater 177,235 129,424 Related party deposits (executive officers and directors) 11,956 7,847 The aggregate amount of overdraft demand deposits reclassified to loans was $94 thousand and $93 thousand at June 30, 2019 and December 31, 2018, respectively. The aggregate amount of maturities for time deposits for each of the five years following the latest balance sheet date totaled $505.9 million, $92.0 million, $15.8 million, $13.1 million and $6.1 million, respectively.

Stock-Based Compensation and Ot

Stock-Based Compensation and Other Benefit Plans	6 Months Ended
	Jun. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation and Other Benefit Plans	NOTE 10. STOCK-BASED COMPENSATION AND OTHER BENEFIT PLANS Spirit of Texas Bancshares, Inc. 2008 Stock Plan (the “2008 Stock Plan”) Option activity for the period indicated is summarized as follows: 2008 Stock Plan Options Weighted Average Exercise Price Aggregate Intrinsic Value (in thousands) Weighted Average Remaining Contractual Life (Years) Outstanding at January 1, 2019 1,116,672 $ 13.04 Granted — Exercised (91,550 ) $ 12.01 $ 960 Forfeited (3,000 ) $ 16.00 Expired — Outstanding at June 30, 2019 1,022,122 $ 13.13 $ 9,577 4.55 Vested and exercisable at June 30, 2019 889,102 $ 12.94 $ 8,500 4.26 The total unrecognized compensation cost of $426 thousand related to the 2008 Stock Plan for the share awards outstanding at June 30, 2019 will be recognized over a weighted average remaining period of 1.50 years. Spirit of Texas Bancshares, Inc. 2017 Stock Plan (the “2017 Stock Plan”) Option activity for the period indicated is summarized as follows: 2017 Stock Plan Options Weighted Average Exercise Price Aggregate Intrinsic Value (in thousands) Weighted Average Remaining Contractual Life (Years) Outstanding at January 1, 2019 205,725 $ 17.45 Granted 850 $ 23.18 $ 1 Exercised (5,000 ) $ 15.00 $ 38 Forfeited — Expired — Outstanding at June 30, 2019 201,575 $ 17.53 $ 1,002 8.21 Vested and exercisable at June 30, 2019 89,379 $ 15.95 $ 585 7.86 The fair values of the stock options granted for the six months ended June 30, 2019 were determined utilizing the Black-Scholes pricing model methodology. A summary of assumptions used to calculate the fair values of the 2017 Stock Plan awards is presented below: 2017 Stock Plan Six Months Ended June 30, 2019 Expected volatility 23.3 % Expected dividend yield 0.0 % Expected term (years) 7.5 Risk-free interest rate 2.58 % Weighted average grant date fair value $ 7.57 The expected volatility is based on the combination of the Company’s historical volatility and the volatility of comparable peer banks. The expected term represents the period of time that the 2017 Stock Plan awards are expected to be outstanding from the date of grant. The risk-free interest rate is based on the U.S. Treasury yields for the expected term of the instrument. The total unrecognized compensation cost of $605 thousand related to the 2017 Stock Plan for the share awards outstanding at June 30, 2019 will be recognized over a weighted average remaining period of 3.62 years. 2017 Stock Plan – Restricted Stock Unit Awards On three different dates during the period ended June 30, 2019, the Company granted a total of 19,500 restricted stock units to employees and directors that vest in full (i.e. cliff vesting) on the five year anniversary of the grant date. The fair value of the restricted stock units on the grant date was $424 thousand and will be recognized as compensation expense over the requisite vesting period ending on the respective five year anniversary of the restricted stock unit award’s grant date. The following table presents the activity during the period related to restricted stock units from the 2017 Stock Plan: 2017 Stock Plan Restricted Stock Unit Awards Shares Weighted Average Grant Date Fair Value Outstanding at January 1, 2019 — $ — Granted 19,500 $ 21.75 Vested — Forfeited — Outstanding at June 30, 2019 19,500 $ 21.75 A summary of selected data related to stock-based compensation expense for the six months ended June 30, 2019 and 2018 are as follows: Restricted Stock Unit Awards June 30, 2019 2018 (Dollars in thousands) Stock-based compensation expense $ 15 $ — Unrecognized compensation expense related to stock-based compensation $ 409 $ — Weighted-average life over which expense is expected to be recognized (years) 4.82 — Warrants Activity for the Bank4Texas Warrants for the period indicated is summarized as follows: Bank4Texas Warrants Warrants Weighted Average Exercise Price Aggregate Intrinsic Value (in thousands) Weighted Average Remaining Contractual Life (Years) Outstanding at January 1, 2019 10,710 $ 10.50 Granted — Exercised (838 ) $ 10.50 $ 10 Forfeited (1) — Expired — Outstanding at June 30, 2019 9,872 $ 10.50 $ 118 1.15 Vested and exercisable at June 30, 2019 9,872 $ 10.50 $ 118 1.15 There was no activity during the three or six months ended June 30, 2019 on the Oasis Warrants.

Basic and Diluted Earnings Per

Basic and Diluted Earnings Per Common Share	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Basic and Diluted Earnings Per Common Share	NOTE 11. BASIC AND DILUTED EARNINGS PER COMMON SHARE The following table presents the computation of basic and diluted EPS: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (Dollars in thousands, except per share data) Net income available to common stockholders $ 5,827 $ 2,681 $ 9,637 $ 4,694 Weighted average number of common shares - basic 13,765,929 8,851,446 12,963,700 8,104,370 Effect of dilutive securities: Employee stock-based compensation awards and warrants 470,315 454,583 469,060 341,590 Weighted average number of common shares - diluted 14,236,244 9,306,029 13,432,760 8,445,960 Basic earnings per common share $ 0.42 $ 0.30 $ 0.74 $ 0.58 Diluted earnings per common share $ 0.41 $ 0.29 $ 0.72 $ 0.56 Anti-dilutive warrants and stock options 9,350 70,266 1,850 70,266

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 12. INCOME TAXES The effective tax rates for the three months ended June 30, 2019 and 2018 were 20.9% and 20.4%, respectively. The increase in the effective tax rate for the three months ended June 30, 2019 was primarily due to nondeductible merger related expenses related to the Beeville acquisition. The effective tax rates for the six months ended June 30, 2019 and 2018 were 19.7% and 20.1%, respectively. The decrease in the effective tax rate for the six months ended June 30, 2019 was primarily due to a return to provision adjustment recorded during the first quarter of 2019.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE 13. COMMITMENTS AND CONTINGENCIES The Company issues off-balance sheet financial instruments in connection with its lending activities and to meet the financing needs of its customers. These financial instruments include commitments to fund loans and lines of credit as well as commercial and standby letters of credit. These commitments expose the Company to varying degrees of credit and market risk which are essentially the same as those involved in extending loans to customers. The Company follows the same credit policies in making commitments as it does for instruments recorded on the Company’s consolidated balance sheet. Collateral is obtained based on management’s assessment of the customer’s credit risk. The Company’s exposure to credit loss is represented by the contractual amount of these commitments. As of June 30, 2019 and December 31, 2018, the Company’s reserve for unfunded commitments totaled $55 thousand and $48 thousand, respectively. Fees collected on off-balance sheet financial instruments represent the fair value of those commitments and are deferred and amortized over their term. Financial Instruments Commitments Unfunded commitments are as follows: June 30, 2019 December 31, 2018 (Dollars in thousands) Unfunded loan commitments $ 211,064 $ 176,156 Commercial and standby letters of credit 1,088 547 Total $ 212,152 $ 176,703 Unfunded loan commitments: 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 creditworthiness on a case-by-case basis. The amount of collateral obtained, if it is deemed necessary by the Company upon extension of credit, is based upon management’s credit evaluation of the counterparty. Collateral held varies but may include accounts receivable, inventory, property, plant and equipment, and income-producing commercial properties. Commercial and standby letters of credit: Letters of credit are conditional commitments issued by the Company to guarantee the performance of a customer to a third party. Letters of credit are primarily issued to support trade transactions or guarantee arrangements. The credit risk involved in issuing letters of credit is essentially the same as that involved in extending loan facilities to customers. The Company generally holds collateral supporting those commitments if deemed necessary. Other Commitments and Contingencies Legal Proceedings The Company, from time to time, is involved as plaintiff or defendant in various legal actions arising in the normal course of business. While the ultimate outcome of any such proceedings cannot be predicted with certainty, it is the opinion of management, based upon advice of legal counsel, that no proceedings exist, either individually or in the aggregate, which, if determined adversely to the Company, would have a material effect on the Company’s consolidated balance sheet, results of operations or cash flows.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	NOTE 14. FAIR VALUE MEASUREMENTS When determining the fair value measurements for assets and liabilities and the related fair value hierarchy, the Company considers the principal or most advantageous market in which it would transact and the assumptions that market participants would use when pricing the asset or liability. When possible, the Company looks to active and observable markets to price identical assets or liabilities. When identical assets and liabilities are not traded in active markets, the Company looks to market observable data for similar assets and liabilities. It is the Company’s policy to maximize the use of observable inputs, minimize the use of unobservable inputs and use unobservable inputs to measure fair value to the extent that observable inputs are not available. The need to use unobservable inputs generally results from the lack of market liquidity, resulting in diminished observability of both actual trades and assumptions that would otherwise be available to value these instruments, or the value of the underlying collateral is not market observable. Although third party price indications may be available for an asset or liability, limited trading activity would make it difficult to support the observability of these quotations. Financial Instruments Carried at Fair Value on a Recurring Basis The following is a description of the valuation methodologies used for financial instruments measured at fair value on a recurring basis, as well as the general classification of each instrument under the valuation hierarchy. Investment Securities—Investment securities available for sale are carried at fair value on a recurring basis. When available, fair value is based on quoted prices for the identical security in an active market and as such, would be classified as Level 1. If quoted market prices are not available, fair values are estimated using quoted prices of securities with similar characteristics, discounted cash flows or matrix pricing models. Investment securities available for sale for which Level 1 valuations are not available are classified as Level 2, and include U.S. Government agencies and sponsored enterprises obligations and agency mortgage-backed securities; state and municipal obligations; asset-backed securities; and corporate debt and other securities. Pricing of these securities is generally spread driven. Observable inputs that may impact the valuation of these securities include benchmark yield curves, credit spreads, reported trades, dealer quotes, bids, issuer spreads, current rating, historical constant prepayment rates, historical voluntary prepayment rates, structural and waterfall features of individual securities, published collateral data, and for certain securities, historical constant default rates and default severities. SBA Servicing Asset—The SBA Servicing Asset is carried at fair value on a recurring basis. To determine the fair value of SBA servicing rights, The Company uses market prices for comparable servicing contracts, when available, or alternatively, uses a valuation model that calculates the present value of estimated future net servicing income. In using this valuation method, the Company incorporates assumptions that market participants would use in estimating future net servicing income, which includes estimates of the cost to service, the discount rate, custodial earnings rate, an inflation rate, ancillary income, prepayment speeds, default rates, late fees and losses. The SBA Servicing Asset is classified as Level 3. The following table presents the assets and liabilities measured at fair value on a recurring basis: June 30, 2019 Level 1 Level 2 Level 3 Total (Dollars in thousands) Assets: U.S. Treasury securities $ 32,536 $ — $ — $ 32,536 U.S. Government agencies — 4,121 — 4,121 State and municipal obligations — 25,418 — 25,418 Residential mortgage-backed securities — 103,303 — 103,303 Corporate bonds and other debt securities — 5,680 — 5,680 SBA servicing rights — — 3,570 3,570 Total $ 32,536 $ 138,522 $ 3,570 $ 174,628 December 31, 2018 Level 1 Level 2 Level 3 Total (Dollars in thousands) Assets: U.S. Government agencies $ — $ 1,934 $ — $ 1,934 State and municipal obligations — 18,048 — 18,048 Residential mortgage-backed securities — 153,974 — 153,974 Corporate bonds and other debt securities — 5,505 — 5,505 SBA servicing rights — — 3,965 3,965 Total $ — $ 179,461 $ 3,965 $ 183,426 There were no transfers of financial assets between levels of the fair value hierarchy during the three or six months ended June 30, 2019. Financial Instruments Measured at Fair Value on a Non-Recurring Basis The following is a description of the methodologies used to estimate the fair values of assets and liabilities measured at fair value on a non-recurring basis, and the level within the fair value hierarchy in which those measurements are typically classified. Impaired loans and other real estate owned (“OREO”)—The carrying amount of collateral dependent impaired loans is typically based on the fair value of the underlying collateral, which may be real estate or other business assets, less estimated costs to sell. The carrying value of OREO is initially measured based on the fair value, less estimated cost to sell, of the real estate acquired in foreclosure and subsequently adjusted to the lower of cost or estimated fair value, less estimated cost to sell. Fair values of real estate collateral are typically based on real estate appraisals which utilize market and income valuation techniques incorporating both observable and unobservable inputs. When current appraisals are not available, the Company may use brokers’ price opinions, home price indices, or other available information about changes in real estate market conditions to adjust the latest appraised value available. These adjustments to appraised values may be subjective and involve significant management judgment. The fair value of collateral consisting of other business assets is generally based on appraisals that use market approaches to valuation, incorporating primarily unobservable inputs. Fair value measurements related to collateral dependent impaired loans and OREO are classified within Level 3 of the fair value hierarchy. The following tables provide information about certain assets measured at fair value on a non-recurring basis: Estimated Fair Value June 30, 2019 December 31, 2018 (Dollars in thousands) Assets (classified in Level 3): Impaired loans $ 3,117 $ 2,696 Other real estate and repossessed assets 1,324 782 Impairment charges resulting from the non-recurring changes in fair value of underlying collateral of impaired loans are included in the provision for loan losses in the consolidated statement of income. Impairment charges resulting from the non-recurring changes in fair value of OREO are included in other real estate and acquired assets resolution expenses in the consolidated statement of income. The following tables show significant unobservable inputs used in the recurring and non-recurring fair value measurements of Level 3 assets: Level 3 Asset Fair Value Valuation Technique Unobservable Inputs Range/Weighted Average June 30, 2019 Non-recurring: Impaired loans $ 3,117 Third party appraisals Collateral discounts 0.0% - 100.0% (20.9%) Other real estate owned 1,324 Third party appraisals Collateral discounts and estimated cost to sell 10.0 % Recurring: SBA servicing assets 3,570 Discounted cash flows Conditional prepayment rate 12.7 % Discount rate 11.5 % December 31, 2018 Non-recurring: Impaired loans $ 2,696 Third party appraisals Collateral discounts 0.0% - 100.0% (19.2%) Other real estate owned 782 Third party appraisals Collateral discounts and estimated cost to sell 10.0 % Recurring: SBA servicing assets 3,965 Discounted cash flows Conditional prepayment rate 11.8 % Discount rate 11.5 % The carrying amounts and estimated fair values, as well as the level within the fair value hierarchy, of the Company’s financial instruments are as follows: June 30, 2019 Carrying Value Fair Value Level 1 Level 2 Level 3 (Dollars in thousands) Financial Assets: Cash and cash equivalents $ 163,158 $ 163,158 $ 163,158 $ — $ — Time deposits in other banks 1,225 1,225 1,225 Available for sale securities 171,058 171,058 32,536 138,522 — FHLB and other bank stock 6,190 6,190 — 6,190 — Loans, net 1,403,061 1,397,245 — — 1,397,245 Loans held for sale 2,583 2,801 — 2,801 — Accrued interest receivable 7,039 7,039 — 7,039 — Bank-owned life insurance 15,432 15,432 — 15,432 — SBA servicing rights 3,570 3,570 — — 3,570 Financial Liabilities: Deposits $ 1,570,604 $ 1,532,821 $ — $ 1,532,821 $ — Accrued interest payable 1,134 1,134 — 1,134 — Long-term borrowings 80,525 77,543 — 77,543 — December 31, 2018 Carrying Value Fair Value Level 1 Level 2 Level 3 (Dollars in thousands) Financial Assets: Cash and cash equivalents $ 89,015 $ 89,015 $ 89,015 $ — $ — Available for sale securities 179,461 179,461 — 179,461 — FHLB and other bank stock 5,304 5,304 — 5,304 — Loans, net 1,086,654 1,075,252 — — 1,075,252 Loans held for sale 3,945 4,200 — 4,200 — Accrued interest receivable 4,934 4,934 — 4,934 — Bank-owned life insurance 7,401 7,401 — 7,401 — SBA servicing rights 3,965 3,965 — — 3,965 Financial Liabilities: Deposits $ 1,182,648 $ 1,181,606 $ — $ 1,181,606 $ — Accrued interest payable 702 702 — 702 — Short-term borrowings 12,500 12,500 — 12,500 — Long-term borrowings 67,916 66,735 — 66,735 — Certain financial instruments are carried at amounts that approximate fair value due to their short-term nature and generally negligible credit risk. Financial instruments for which fair value approximates the carrying amount at June 30, 2019 and December 31, 2018, include cash and cash equivalents, time deposits in other banks and accrued interest receivable and payable.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	NOTE 15. SUBSEQUENT EVENTS On July 24, 2019, the Company and Chandler Bancorp, Inc., a Texas corporation (“Chandler”), entered into an Agreement and Plan of Reorganization (the “Reorganization Agreement”), joined in by Kidd Partners, Ltd., a Texas limited partnership, as sole shareholder of Chandler (“Kidd Partners”), providing for the acquisition by the Company of Chandler through the merger of Chandler with and into the Company, with the Company surviving the merger. Pursuant to the terms and subject to the conditions of the Reorganization Agreement, which has been approved by the Board of Directors of each of the Company and Chandler and by Kidd Partners, as the sole shareholder of Chandler, the transaction provides for the payment to the sole shareholder of Chandler of (i) $19.2 million in cash, subject to adjustment described in the Reorganization Agreement, and (ii) 2,100,000 shares of the Company’s common stock, subject to adjustment described in the Reorganization Agreement. Based on the closing price of $22.10 for the Company’s common stock on July 23, 2019, the transaction would have an aggregate value of $65.6 million. On July 25, 2019, the Company and the Bank entered into an underwriting agreement (the “Underwriting Agreement”) with Stephens Inc. and Keefe, Bruyette & Woods, Inc., as representatives of the several underwriters named in Schedule A thereto (collectively, the “Underwriters”), to issue and sell 2,000,000 shares of the Company’s common stock, no par value per share (“Common Stock”), at a public offering price of $21.50 per share in an underwritten public offering (the “Offering”). As part of the Offering, the Company granted the Underwriters a 30-day option to purchase up to an additional 300,000 shares of its common stock at the public offering price, less the underwriting discount In connection with the Offering, the Company issued and sold 2,300,000 shares of its common stock, including 300,000 shares sold pursuant to the Underwriters’ full exercise of their option to purchase additional shares, for net proceeds of approximately $46.3 million after deducting underwriting discounts and commissions and estimated offering expenses. The Company intends to use approximately $19.2 million of the net proceeds from the Offering to fund the cash portion of the merger consideration to be paid to the sole shareholder of Chandler in the Company’s acquisition of Chandler and its subsidiary, Citizens State Bank, and approximately $21.0 million of the net proceeds from this Offering to pay off a line of credit with a third-party lender. The remaining net proceeds will be used by the Company for other general corporate purposes in order to support its continued growth, including investments in its bank subsidiary and future strategic acquisitions.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations Spirit of Texas Bancshares, Inc. (the “Holding Company” or “Company”) is a bank holding company headquartered in Conroe, Texas that provides, through its bank subsidiary, a variety of financial services to individuals and corporate customers in Texas, which are primarily agricultural, light industrial and commercial areas. The Company consummated the underwritten initial public offering of its common stock in May 2018. In connection with the initial public offering, the Company issued and sold 2,300,000 shares of its common stock, including 300,000 shares of common stock sold pursuant to the underwriters’ full exercise of their option to purchase additional shares, at an offering price of $21.00 per share, for aggregate gross proceeds of $48.3 million before deducting underwriting discounts and offering expenses, and aggregate net proceeds of $42.1 million after deducting underwriting discounts and offering expenses.
Basis of Presentation	Basis of Presentation The consolidated financial statements include the accounts of the Holding Company and the accounts of its wholly-owned subsidiary, Spirit of Texas Bank SSB (the “Bank”). All significant intercompany balances and transactions have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and Article 8 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. Operating results for the period ended June 30, 2019 are not necessarily indicative of the results that may be expected for the year ending December 31, 2019 and should be read in conjunction with the audited financial statements and notes thereto for the year ended December 31, 2018 previously filed with the Securities and Exchange Commission (“SEC”) in the Company’s Annual Report on Form 10-K In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for the fair presentation of these consolidated financial statements have been included. The preparation of financial statements in conformity with these accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and income and expense during the reporting periods and the related disclosures. Although management’s estimates and assumptions are based on current expectations, estimates, forecasts and projections about future performance of the Company, such estimates and assumptions are not guarantees of future performance and involve certain risks, uncertainties and assumptions that are difficult for the Company to assess. Operating results for the interim periods disclosed herein are not necessarily indicative of the results that may be expected for a full year or any future period.
Accounting Policies Recently Adopted and Pending Accounting Pronouncements	Accounting Policies Recently Adopted and Pending Accounting Pronouncements Accounting Standards Update (ASU) 2019-04, “Codification Improvements to Topic 326, Financial Instruments-Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments” – issued in April 2019, ASU No. 2019-04 clarifies a number of issues discussed at the June 2018 and November 2018 Credit Losses Transition Resource Group meetings. The clarifications address a variety of identified issues including but not limited to the treatment of accrued interest receivable as it relates to the allowance for credit losses, transfers between loan classifications and categories, recoveries, and using projections of future interest rate environments in expected cash flow calculations. Management is evaluating these clarifications concurrently with our assessment of ASU 2016-13. ASU 2018-13, “Fair Value Measurement Disclosure Framework” – issued in August 2018, ASU No. 2018-13 modifies the disclosure requirements on fair value measurements outlined in Topic 820, Fair Value Measurements. Specifically the amendments in the ASU remove the requirements to disclose the amount and reasons for transfers between fair value hierarchy levels, the policy for timing of transfers between levels, the valuation processes for Level 3 fair value measurements, and for nonpublic entities, disclosure of the changes in unrealized gains and losses for the period included in earnings for recurring Level 3 fair value measurements. Additionally, the ASU adds disclosure requirements regarding changes in unrealized gains and losses for the period included in other comprehensive income related to Level 3 fair value measurements, and disclosure of the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. The amendments of ASU 2018-13 are effective for all entities for interim and annual periods beginning after December 15, 2019. Management adopted the provisions of this ASU removing fair value disclosure requirements as of December 31, 2018 as early adoption of the removal provisions was allowed and will adopt the remaining provisions of the ASU as of the effective date. ASU 2018-09, “Codification Improvements.” - issued in July 2018, ASU No. 2018-09 makes changes to a variety of topics to clarify, correct errors in, or make minor improvements to the Accounting Standards Codification. The majority of the amendments in ASU 2018-09 will be effective in annual periods beginning after December 15, 2018. ASU 2018-09 is not expected to have a material impact on the Company’s consolidated financial statements. ASU 2017-04, “Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment.” Issued in January 2017, ASU 2017-04 simplifies the manner in which an entity is required to test goodwill for impairment by eliminating Step 2 from the goodwill impairment test. Step 2 measures a goodwill impairment loss by comparing the implied fair value of a reporting unit’s goodwill with the carrying amount of that goodwill. In computing the implied fair value of goodwill under Step 2, an entity, prior to the amendments in ASU 2017-04, had to perform procedures to determine the fair value at the impairment testing date of its assets and liabilities, including unrecognized assets and liabilities, in accordance with the procedure that would be required in determining the fair value of assets acquired and liabilities assumed in a business combination. However, under the amendments in ASU 2017-04, an entity should (1) perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount, and (2) recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, with the understanding that the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Additionally, ASU 2017-04 removes the requirements for any reporting unit with a zero or negative carrying amount to perform a qualitative assessment and, if it fails such qualitative test, to perform Step 2 of the goodwill impairment test. ASU 2017-04 is effective prospectively for public entities for annual, or any interim, goodwill impairment tests in fiscal years beginning after December 15, 2019 and for all other entities for impairment tests in fiscal years beginning after December 15, 2021. Management will adopt this ASU using the public company effective date as early adoption is permitted and will continue to evaluate the impact this ASU will have on the consolidated financial statements through its effective date; however, the adoption of ASU 2017-04 is not expected to have a material impact on the Company’s consolidated financial statements. ASU 2016-13, “Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” Issued in June 2016, ASU 2016-13 will add FASB ASC Topic 326, “Financial Instruments-Credit Losses” and finalizes amendments to FASB ASC Subtopic 825-15, “Financial Instruments-Credit Losses.” The amendments of ASU 2016-13 are intended to provide financial statement users with more decision-useful information related to expected credit losses on financial instruments and other commitments to extend credit by replacing the current incurred loss impairment methodology with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to determine credit loss estimates. The amendments of ASU 2016-13 eliminate the probable initial recognition threshold and, in turn, reflect an entity’s current estimate of all expected credit losses. ASU 2016-13 does not specify the method for measuring expected credit losses, and an entity is allowed to apply methods that reasonably reflect its expectations of the credit loss estimate. Additionally, the amendments of ASU 2016-13 require that credit losses on available for sale debt securities be presented as an allowance rather than as a write-down. The amendments of ASU 2016-13 were originally effective for public entities for interim and annual periods beginning after December 15, 2019 and for all other entities for periods beginning after December 15, 2020. Issued in November 2018, ASU 2018-19 , alters the effective date of ASU 2016-13 for private companies. Under the provisions of ASU 2018-19, ASU 2016-13 is now effective for fiscal years beginning after December 15, 2021 including interim periods within those years for non-public business entities. Earlier application is permitted for interim and annual periods beginning after December 15, 2018. Management has elected to adopt this ASU using the updated private company effective date and is currently evaluating the impact this ASU will have on the consolidated financial statements and that evaluation will depend on economic conditions and the composition of the Company’s loan and lease portfolio at the time of adoption. ASU 2016-02, “Leases (Topic 842).” Issued in February 2016, ASU 2016-02 was issued by the FASB to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and by disclosing key information about leasing arrangements. ASU 2016-02 will, among other things, require lessees to recognize a lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. ASU 2016-02 does not significantly change lease accounting requirements applicable to lessors; however, the ASU contains some targeted improvements that are intended to align, where necessary, lessor accounting with the lessee accounting model and with the updated revenue recognition guidance issued in 2014. The amendments of ASU 2016-02 are effective for public entities for interim and annual periods beginning after December 15, 2018 and for other entities for periods beginning after December 15, 2019. The adoption of this ASU will result in an increase to the Consolidated Balance Sheets for right-of-use assets and associated lease liabilities for operating leases in which the Company is the lessee. Under current accounting standards, all of the Company's leases are classified as operating leases and, as such, are not recognized on the Company's Consolidated Balance Sheet. Additionally, in July 2018, the FASB issued ASU No. 2018-10, Codification Improvements to Topic 842, Leases and ASU No. 2018-11, Leases, Targeted Improvements. The amendments in these updates provide additional clarification and implementation guidance on certain aspects of ASU 2016-02 and have the same effective and transition requirements as ASU 2016-02. Specifically, ASU 2018-11 creates an additional transition method option allowing entities to record a cumulative effect adjustment to opening retained earnings in the year of adoption. In December 2018, the FASB further issued ASU 2018-20, Leases (Topic 842) Narrow-Scope Improvements for Lessors . The amendments in this update permits lessors to make an accounting policy election to not evaluate whether certain sales taxes and other similar taxes are lessor costs or lessee costs and instead account for the costs as if they were lessee costs. Additionally, the amendment requires lessors to exclude from variable payments, and therefore revenue, lessor costs paid by lessees directly to third parties. The amendments also require lessors to account for costs excluded from the consideration of a contract that are paid by the lessor and reimbursed by the lessee as variable payments. In March 2019, the FASB also issued ASU 2019-01, Leases (Topic 842) Codification Improvements, to further clarify certain identified issues regarding implementation of ASU 2016-02. Specifically, the amendments in ASU 2019-01 clarify the determination of fair value of underlying assets by lessors that are not manufacturers or dealers, the cash flow presentation of sales-type or direct financing leases, and transition disclosures for interim periods. Management will adopt these ASUs using the private company effective date of January 1, 2020 and is currently evaluating the impact to the consolidated financial statements and related method of adoption, specifically, we are in the process of determining an appropriate discount rate to record identified right-of-use assets.

Revenue Recognition (Tables)

Revenue Recognition (Tables)	6 Months Ended
	Jun. 30, 2019
Revenue From Contract With Customer [Abstract]
Schedule of Non-Interest Income, Segregated by Revenue Streams in-Scope and Out-of-Scope of Topic 606	The following presents non-interest income, segregated by revenue streams in-scope and out-of-scope of Topic 606, for the three and six months ended June 30, 2019 and 2018: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Non-Interest Income In-scope of Topic 606 Deposit accounts core service charges $ 149 $ 78 $ 261 $ 145 Deposit account transaction based fee income 829 344 1,460 639 Mortgage referral fees 198 208 308 364 Non-Interest Income (in-scope of Topic 606) 1,176 630 2,029 1,148 Non-Interest Income (out-of-scope of Topic 606) 2,599 1,673 4,803 3,743 Total Non-Interest Income $ 3,775 $ 2,303 $ 6,832 $ 4,891

Business Combinations (Tables)

Business Combinations (Tables)	6 Months Ended
	Jun. 30, 2019
Comanche National Corporation
Fair Values of Assets Acquired and Liabilities Assumed	Fair values of the assets acquired and liabilities assumed in this transaction as of the closing date are as follows: Assets of acquired bank (Dollars in thousands): Cash and cash equivalents $ 57,135 Securities available for sale 144,735 Loans held for investment 116,220 Premises and equipment, net 6,634 Other real estate owned 33 Goodwill 13,768 Core deposit intangible 5,988 Other assets 11,712 Total assets acquired $ 356,225 Liablilities of acquired bank: Deposits $ 297,778 Trust preferred securities 2,811 Other liabilities 2,698 Total liabilities assumed $ 303,287 Common stock issued at $18.99 per share $ 40,692 Cash paid $ 12,246
First Beeville Financial Corporation
Fair Values 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 (Dollars in thousands): Cash and cash equivalents $ 60,941 Securities available for sale 57,206 Loans held for investment 296,348 Premises and equipment, net 6,067 Other real estate owned 1,359 Goodwill 25,636 Core deposit intangible 5,635 Other assets 12,860 Total assets acquired $ 466,052 Liabilities of acquired bank: Deposits $ 399,654 Other liabilities 543 Total liabilities assumed $ 400,197 Common stock issued at $21.20 per share $ 33,480 Cash paid $ 32,375

Investment Securities (Tables)

Investment Securities (Tables)	6 Months Ended
	Jun. 30, 2019
Investments Debt And Equity Securities [Abstract]
Schedule of Fair Values of Securities Available for Sale	The amortized cost, gross unrealized gains and losses and approximate fair values of securities available for sale are as follows: Amortized Unrealized Fair June 30, 2019 Cost Gains Losses Value (Dollars in thousands) Available for sale: U.S. Treasury securities $ 32,537 $ 3 $ 4 $ 32,536 U.S. Government agencies 4,084 37 - 4,121 State and municipal obligations 24,988 459 29 25,418 Residential mortgage-backed securities 102,151 2,306 1,154 103,303 Corporate bonds and other debt securities 5,645 38 3 5,680 Total available for sale $ 169,405 $ 2,843 $ 1,190 $ 171,058 Amortized Unrealized Fair December 31, 2018 Cost Gains Losses Value (Dollars in thousands) Available for sale: U.S. Government agencies $ 2,015 $ — $ 81 $ 1,934 State and municipal obligations 17,201 847 — 18,048 Residential mortgage-backed securities 152,232 2,614 872 153,974 Corporate bonds and other debt securities 5,667 — 162 5,505 Total available for sale $ 177,115 $ 3,461 $ 1,115 $ 179,461
Schedule of Securities Available for Sale by Contractual Maturity	The amortized cost and estimated fair value of securities available for sale, by contractual maturity, are as follows: Amortized Fair June 30, 2019 Cost Value (Dollars in thousands) Available for sale: Due in one year or less $ 9,695 $ 9,690 Due after one year through five years 43,470 43,535 Due after five years through ten years 8,417 8,459 Due after ten years 5,672 6,071 Residential mortgage-backed securities 102,151 103,303 Total available for sale $ 169,405 $ 171,058
Schedule of Investment Securities Available for Sale and Aggregated by Investment Category and Length of Time Individual Securities in Continuous Unrealized Loss Position	The following tables present the estimated fair values and gross unrealized losses on investment securities available for sale, aggregated by investment category and length of time individual securities have been in a continuous unrealized loss position as of the periods presented: Less than 12 Months 12 Months or More Total June 30, 2019 Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss (Dollars in thousands) Available for sale: U.S. Treasury securities $ 14,447 $ 4 $ - $ - $ 14,447 $ 4 U.S. Government agencies — — - - - - State and municipal obligations — — 11,014 29 11,014 29 Residential mortgage-backed securities — — 26,009 1,154 26,009 1,154 Corporate bonds and other debt securities — — 1,996 3 1,996 3 Total available for sale $ 14,447 $ 4 $ 39,019 $ 1,186 $ 53,466 $ 1,190 Less than 12 Months 12 Months or More Total December 31, 2018 Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss (Dollars in thousands) Available for sale: U.S. Government agencies $ — $ — $ 1,934 $ 81 $ 1,934 $ 81 State and municipal obligations — — — — — — Residential mortgage-backed securities 1 — 25,479 872 25,480 872 Corporate bonds and other debt securities — — 5,505 162 5,505 162 Total available for sale $ 1 $ — $ 32,918 $ 1,115 $ 32,919 $ 1,115

Loans, Net (Tables)

Loans, Net (Tables)	6 Months Ended
	Jun. 30, 2019
Receivables [Abstract]
Summary of Loans	Loans consisted of the following at June 30, 2019 and December 31, 2018: June 30, 2019 December 31, 2018 (Dollars in thousands) Commercial and industrial loans (1) $ 197,774 $ 173,892 Real estate: 1-4 single family residential loans 277,560 275,644 Construction, land and development 176,567 159,734 Commercial real estate loans (including multifamily) 666,981 397,953 Consumer loans and leases 20,745 24,378 Municipal and other loans 69,711 61,339 Total loans held in portfolio (2) $ 1,409,338 $ 1,092,940 Allowance for loan losses (6,277 ) (6,286 ) Loans held in portfolio, net $ 1,403,061 $ 1,086,654 (1) Balance includes $71.3 million and $76.9 million of the unguaranteed portion of SBA loans as of June 30, 2019 and December 31, 2018, respectively.
Summary of Loans to Related Parties and Principal Owners	In the ordinary course of business, the Company makes loans to executive officers and directors. Loans to these related parties, including companies in which they are principal owners, are as follows: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (Dollars in thousands) Principal outstanding, beginning of year $ 93 $ 442 $ 107 $ 463 Additions (reductions) of affiliations 2,352 — 2,352 — New loans made in current year — — — — Repayments (12 ) (21 ) (26 ) (42 ) Principal outstanding, end of year $ 2,433 $ 421 $ 2,433 $ 421

Allowance for Loan and Lease _2

Allowance for Loan and Lease Losses (Tables)	6 Months Ended
	Jun. 30, 2019
Receivables [Abstract]
Allowance for Loan and Lease Losses	The following tables present information related to allowance for loan and lease losses for the periods presented: Allowance Rollforward Three Months Ended June 30, 2019 Beginning Balance Charge-offs Recoveries Provision Ending Balance (Dollars in thousands) Commercial and industrial loans $ 4,661 $ (643 ) $ 31 $ 168 $ 4,217 Real estate: 1-4 single family residential loans 34 — — (2 ) 32 Construction, land and development loans 749 — — 45 794 Commercial real estate loans (including multifamily) 1,057 — — 134 1,191 Consumer loans and leases 57 (16 ) 3 (9 ) 35 Municipal and other loans 11 — 1 (4 ) 8 Ending allowance balance $ 6,569 $ (659 ) $ 35 $ 332 $ 6,277 Allowance Rollforward Three Months Ended June 30, 2018 Beginning Balance Charge-offs Recoveries Provision Ending Balance (Dollars in thousands) Commercial and industrial loans $ 2,906 $ (321 ) $ 3 $ 2,298 $ 4,886 Real estate: 1-4 single family residential loans 887 (5 ) — (564 ) 318 Construction, land and development loans 540 — — (345 ) 195 Commercial real estate loans (including multifamily) 1,032 — — (799 ) 233 Consumer loans and leases 175 (24 ) — 195 346 Municipal and other loans 187 — — (150 ) 37 Ending allowance balance $ 5,727 $ (350 ) $ 3 $ 635 $ 6,015 Allowance Rollforward Six Months Ended June 30, 2019 Beginning Balance Charge-offs Recoveries Provision Ending Balance (Dollars in thousands) Commercial and industrial loans $ 4,453 $ (1,221 ) $ 59 $ 926 $ 4,217 Real estate: 1-4 single family residential loans 59 — — (27 ) 32 Construction, land and development loans 731 — — 63 794 Commercial real estate loans (including multifamily) 960 — — 231 1,191 Consumer loans and leases 80 (34 ) 5 (16 ) 35 Municipal and other loans 3 — 1 4 8 Ending allowance balance $ 6,286 $ (1,255 ) $ 65 $ 1,181 $ 6,277 Allowance Rollforward Six Months Ended June 30, 2018 Beginning Balance Charge-offs Recoveries Provision Ending Balance (Dollars in thousands) Commercial and industrial loans $ 3,046 $ (645 ) $ 69 $ 2,416 $ 4,886 Real estate: 1-4 single family residential loans 902 (5 ) — (579 ) 318 Construction, land and development loans 441 — — (246 ) 195 Commercial real estate loans (including multifamily) 898 — — (665 ) 233 Consumer loans and leases 198 (30 ) — 178 346 Municipal and other loans 167 — — (130 ) 37 Ending allowance balance $ 5,652 $ (680 ) $ 69 $ 974 $ 6,015
Summary of Aging Analysis of Recorded Investment for Delinquent Loans by Portfolio and Segment	The following tables present an aging analysis of the recorded investment for delinquent loans by portfolio and segment: Accruing June 30, 2019 Current 30 to 59 Days Past Due 60 to 89 Days Past Due 90 Days or More Past Due Non- Accrual Total (Dollars in thousands) Commercial and industrial loans $ 192,098 $ 332 $ 62 $ — $ 5,282 $ 197,774 Real estate: 1-4 single family residential loans 277,004 303 45 — 208 277,560 Construction, land and development 174,373 2,194 — — — 176,567 Commercial real estate loans (including multifamily) 665,764 13 1,068 — 136 666,981 Consumer loans and leases 20,495 157 47 — 46 20,745 Municipal and other loans 69,576 — 82 — 53 69,711 Total loans $ 1,399,310 $ 2,999 $ 1,304 $ — $ 5,725 $ 1,409,338 Accruing December 31, 2018 Current 30 to 59 Days Past Due 60 to 89 Days Past Due 90 Days or More Past Due Non- Accrual Total (Dollars in thousands) Commercial and industrial loans $ 169,206 $ 605 $ 223 $ 288 $ 3,570 $ 173,892 Real estate: 1-4 single family residential loans 273,909 581 64 — 1,090 275,644 Construction, land and development 159,723 11 — — — 159,734 Commercial real estate loans (including multifamily) 396,559 451 589 — 354 397,953 Consumer loans and leases 24,109 208 44 — 17 24,378 Municipal and other loans 61,289 50 — — — 61,339 Total loans $ 1,084,795 $ 1,906 $ 920 $ 288 $ 5,031 $ 1,092,940
Summary of Loans by Key Indicators of Credit Quality	The following table summarizes the Company’s loans by key indicators of credit quality: June 30, 2019 Pass Special Mention Substandard Doubtful (Dollars in thousands) Commercial and industrial loans $ 191,854 $ 2,812 $ 3,108 $ — Real estate: 1-4 single family residential loans 276,076 951 533 — Construction, land and development 175,610 10 947 — Commercial real estate loans (including multifamily) 660,606 3,214 3,161 — Consumer loans and leases 20,734 — 11 — Municipal and other loans 69,711 — — — Total loans $ 1,394,591 $ 6,987 $ 7,760 $ — December 31, 2018 Pass Special Mention Substandard Doubtful (Dollars in thousands) Commercial and industrial loans $ 163,908 $ 3,170 $ 6,601 $ 213 Real estate: 1-4 single family residential loans 270,839 1,714 2,547 544 Construction, land and development 157,688 24 2,022 — Commercial real estate loans (including multifamily) 383,323 12,412 1,806 412 Consumer loans and leases 20,798 1,836 180 1,564 Municipal and other loans 60,837 484 — 18 Total loans $ 1,057,393 $ 19,640 $ 13,156 $ 2,751
Summary of Investment in Loans Disaggregated Based on Method of Evaluating Impairment	The following table shows the Company’s investment in loans disaggregated based on the method of evaluating impairment: Loans - Recorded Investment Allowance for Credit Loss June 30, 2019 Individually Evaluated for Impairment Collectively Evaluated for Impairment Individually Evaluated for Impairment Collectively Evaluated for Impairment (Dollars in thousands) Commercial and industrial loans $ 3,783 $ 193,991 $ 1,618 $ 2,599 Real estate: 1-4 single family residential loans 1,401 276,159 4 28 Construction, land and development 219 176,348 — 794 Commercial real estate loans (including multifamily) 241 666,740 — 1,191 Consumer loans and leases 16 20,729 4 31 Municipal and other loans — 69,711 — 8 Total loans $ 5,660 $ 1,403,678 $ 1,626 $ 4,651 Loans - Recorded Investment Allowance for Credit Loss December 31, 2018 Individually Evaluated for Impairment Collectively Evaluated for Impairment Individually Evaluated for Impairment Collectively Evaluated for Impairment (Dollars in thousands) Commercial and industrial loans $ 3,640 $ 170,252 $ 1,234 $ 3,219 Real estate: 1-4 single family residential loans 1,193 274,451 29 30 Construction, land and development — 159,734 — 731 Commercial real estate loans (including multifamily) — 397,953 — 960 Consumer loans and leases 17 24,361 4 76 Municipal and other loans — 61,339 — 3 Total loans $ 4,850 $ 1,088,090 $ 1,267 $ 5,019
Summary of Information Regarding Impaired Loans Evaluated for Specific Reserves	The following tables set forth certain information regarding the Company’s impaired loans that were evaluated for specific reserves: Impaired Loans - With Allowance Impaired Loans - With no Allowance June 30, 2019 Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance (Dollars in thousands) Commercial and industrial loans $ 3,124 $ 6,490 $ 1,618 $ 659 $ 3,170 Real estate: 1-4 single family residential loans 152 160 4 1,249 1,582 Construction, land and development — — — 219 223 Commercial real estate loans (including multifamily) — — — 241 246 Consumer loans and leases 16 16 4 — — Municipal and other loans — — — — — Total loans $ 3,292 $ 6,666 $ 1,626 $ 2,368 $ 5,221 Impaired Loans - With Allowance Impaired Loans - With no Allowance December 31, 2018 Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance (Dollars in thousands) Commercial and industrial loans $ 1,843 $ 5,392 $ 1,234 $ 1,797 $ 3,500 Real estate: 1-4 single family residential loans 116 124 29 1,077 1,086 Construction, land and development — — — — — Commercial real estate loans (including multifamily) — — — — — Consumer loans and leases 17 17 4 — — Municipal and other loans — — — — — Total loans $ 1,976 $ 5,533 $ 1,267 $ 2,874 $ 4,586 Three Months Ended June 30, 2019 2018 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized (Dollars in thousands) Commercial and industrial loans $ 3,691 $ — $ 2,435 $ — Real estate: 1-4 single family residential loans 1,282 — 1,511 — Construction, land and development 220 — 24 — Commercial real estate loans (including multifamily) 243 — 149 — Consumer loans and leases 16 — 101 — Municipal and other loans — — — — Total loans $ 5,452 $ — $ 4,220 $ — Six Months Ended June 30, 2019 2018 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized (Dollars in thousands) Commercial and industrial loans $ 3,797 $ — $ 2,620 $ — Real estate: 1-4 single family residential loans 1,295 — 1,518 — Construction, land and development 222 — 25 — Commercial real estate loans (including multifamily) 245 — 151 — Consumer loans and leases 17 — 103 — Municipal and other loans — — — — Total loans $ 5,576 $ — $ 4,417 $ —
Summary of Troubled Debt Restructurings (TDRs) Based Upon Delinquency Status	The following table provides a summary of troubled debt restructurings (“TDRs”) based upon delinquency status, all of which are considered impaired: June 30, 2019 December 31, 2018 Number of contracts Recorded Investment Number of contracts Recorded Investment (Dollars in thousands) Performing TDRs: Commercial and industrial loans 3 $ 122 3 $ 69 Real estate: 1-4 single family residential loans 2 132 2 141 Construction, land and development — — — — Commercial real estate loans (including multifamily) — — — — Consumer loans and leases — — — — Municipal and other loans — — — — Total performing TDRs 5 254 5 210 Nonperforming TDRs 9 455 7 448 Total TDRs 14 $ 709 12 $ 658 Allowance attributable to TDRs $ 224 $ 149
Summary of TDRs Includes Newly Designated TDRs and Modifications to Existing TDRs	The following table summarizes TDRs and includes newly designated TDRs as well as modifications made to existing TDRs. Modifications may include, but are not limited to, granting a material extension of time, entering into a forbearance agreement, adjusting the interest rate, accepting interest only payments for an extended period of time, a change in the amortization period or a combination of any of these. Post-modification balances represent the recorded investment at the end of Day 2 in which the modification was made: Three Months Ended June 30, 2019 2018 Number of Contracts Pre- Modification Outstanding Recorded Investment Post- Modification Outstanding Recorded Investment Related Allowance Number of Contracts Pre- Modification Outstanding Recorded Investment Post- Modification Outstanding Recorded Investment Related Allowance (Dollars in thousands) Commercial and industrial loans 3 $ 185 $ 185 $ 88 2 $ 73 $ 73 $ 53 Real estate: 1-4 single family residential loans — — — — 1 34 34 — Construction, land and development — — — — — — — — Commercial real estate loans (including multifamily) — — — — — — — — Consumer loans and leases — — — — — — — — Municipal and other loans — — — — — — — — Six Months Ended June 30, 2019 2018 Number of Contracts Pre- Modification Outstanding Recorded Investment Post- Modification Outstanding Recorded Investment Related Allowance Number of Contracts Pre- Modification Outstanding Recorded Investment Post- Modification Outstanding Recorded Investment Related Allowance (Dollars in thousands) Commercial and industrial loans 3 $ 185 $ 185 $ 88 7 $ 442 $ 442 $ 192 Real estate: 1-4 single family residential loans — — — — 1 34 34 — Construction, land and development — — — — — — — — Commercial real estate loans (including multifamily) — — — — — — — — Consumer loans and leases — — — — — — — — Municipal and other loans — — — — — — — —

Goodwill and Intangibles (Table

Goodwill and Intangibles (Tables)	6 Months Ended
	Jun. 30, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Goodwill and Other Intangible Assets	Goodwill and other intangible assets, which consist of core deposit intangibles, are summarized as follows: Six Months Ended June 30, 2019 Year Ended December 31, 2018 (Dollars in thousands) Beginning goodwill $ 18,253 $ 4,485 Arising from business combination 25,636 13,768 Ending goodwill $ 43,889 $ 18,253 Core deposit intangible 8,558 13,166 Arising from business combination 10,244 — Less: Accumulated amortization (6,219 ) (4,608 ) Core deposit intangible, net $ 12,583 $ 8,558
Schedule of Estimated Amortization Expense for Intangible Assets	The estimated amount of amortization expense for core deposit intangible assets to be recognized over the next five fiscal years is as follows: Type of intangibles Remainder of 2019 2020 2021 2022 2023 2024 (Dollars in thousands) Core deposit intangible $ 1,977 $ 3,503 $ 2,852 $ 2,063 $ 1,378 $ 649

SBA Servicing Asset (Tables)

SBA Servicing Asset (Tables)	6 Months Ended
	Jun. 30, 2019
Transfers And Servicing Of Financial Assets [Abstract]
Summary of Activity Pertaining to SBA Servicing Rights	The following summarizes the activity pertaining to SBA servicing rights, which are in the consolidated balance sheets, for the three and six months ended June 30, 2019 and 2018: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (Dollars in thousands) Beginning balance $ 3,747 $ 3,512 $ 3,965 $ 3,411 Origination of servicing assets 322 247 520 579 Change in fair value: Due to run-off (239 ) (245 ) (404 ) (453 ) Due to market changes (260 ) 7 (511 ) (16 ) Ending balance $ 3,570 $ 3,521 $ 3,570 $ 3,521

Deposits (Tables)

Deposits (Tables)	6 Months Ended
	Jun. 30, 2019
Banking And Thrift [Abstract]
Summary of Deposits by Category	The following table sets forth the Company’s deposits by category: June 30, 2019 December 31, 2018 (Dollars in thousands) Noninterest-bearing demand deposits $ 367,892 $ 256,784 Interest-bearing demand deposits 292,550 124,933 Interest-bearing NOW accounts 7,638 7,961 Savings and money market accounts 269,651 245,928 Time deposits 632,873 547,042 Total deposits $ 1,570,604 $ 1,182,648 Time deposits $100,000 and greater $ 500,044 $ 422,447 Time deposits $250,000 and greater 177,235 129,424 Related party deposits (executive officers and directors) 11,956 7,847

Stock-Based Compensation and _2

Stock-Based Compensation and Other Benefit Plans (Tables)	6 Months Ended
	Jun. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Assumptions Used to Calculated Fair Value Utilizing Black-Scholes Pricing Model	The fair values of the stock options granted for the six months ended June 30, 2019 were determined utilizing the Black-Scholes pricing model methodology. A summary of assumptions used to calculate the fair values of the 2017 Stock Plan awards is presented below: 2017 Stock Plan Six Months Ended June 30, 2019 Expected volatility 23.3 % Expected dividend yield 0.0 % Expected term (years) 7.5 Risk-free interest rate 2.58 % Weighted average grant date fair value $ 7.57
Summary of Activity Related to Restricted Stock Units	The following table presents the activity during the period related to restricted stock units from the 2017 Stock Plan: 2017 Stock Plan Restricted Stock Unit Awards Shares Weighted Average Grant Date Fair Value Outstanding at January 1, 2019 — $ — Granted 19,500 $ 21.75 Vested — Forfeited — Outstanding at June 30, 2019 19,500 $ 21.75
Summary of Stock Based Compensation Expense	A summary of selected data related to stock-based compensation expense for the six months ended June 30, 2019 and 2018 are as follows: Restricted Stock Unit Awards June 30, 2019 2018 (Dollars in thousands) Stock-based compensation expense $ 15 $ — Unrecognized compensation expense related to stock-based compensation $ 409 $ — Weighted-average life over which expense is expected to be recognized (years) 4.82 —
Bank4Texas Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Warrant Activity	Activity for the Bank4Texas Warrants for the period indicated is summarized as follows: Bank4Texas Warrants Warrants Weighted Average Exercise Price Aggregate Intrinsic Value (in thousands) Weighted Average Remaining Contractual Life (Years) Outstanding at January 1, 2019 10,710 $ 10.50 Granted — Exercised (838 ) $ 10.50 $ 10 Forfeited (1) — Expired — Outstanding at June 30, 2019 9,872 $ 10.50 $ 118 1.15 Vested and exercisable at June 30, 2019 9,872 $ 10.50 $ 118 1.15
2008 Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Option Activity	Option activity for the period indicated is summarized as follows: 2008 Stock Plan Options Weighted Average Exercise Price Aggregate Intrinsic Value (in thousands) Weighted Average Remaining Contractual Life (Years) Outstanding at January 1, 2019 1,116,672 $ 13.04 Granted — Exercised (91,550 ) $ 12.01 $ 960 Forfeited (3,000 ) $ 16.00 Expired — Outstanding at June 30, 2019 1,022,122 $ 13.13 $ 9,577 4.55 Vested and exercisable at June 30, 2019 889,102 $ 12.94 $ 8,500 4.26
2017 Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Option Activity	Option activity for the period indicated is summarized as follows: 2017 Stock Plan Options Weighted Average Exercise Price Aggregate Intrinsic Value (in thousands) Weighted Average Remaining Contractual Life (Years) Outstanding at January 1, 2019 205,725 $ 17.45 Granted 850 $ 23.18 $ 1 Exercised (5,000 ) $ 15.00 $ 38 Forfeited — Expired — Outstanding at June 30, 2019 201,575 $ 17.53 $ 1,002 8.21 Vested and exercisable at June 30, 2019 89,379 $ 15.95 $ 585 7.86

Basic and Diluted Earnings Pe_2

Basic and Diluted Earnings Per Common Share (Tables)	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted EPS	The following table presents the computation of basic and diluted EPS: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (Dollars in thousands, except per share data) Net income available to common stockholders $ 5,827 $ 2,681 $ 9,637 $ 4,694 Weighted average number of common shares - basic 13,765,929 8,851,446 12,963,700 8,104,370 Effect of dilutive securities: Employee stock-based compensation awards and warrants 470,315 454,583 469,060 341,590 Weighted average number of common shares - diluted 14,236,244 9,306,029 13,432,760 8,445,960 Basic earnings per common share $ 0.42 $ 0.30 $ 0.74 $ 0.58 Diluted earnings per common share $ 0.41 $ 0.29 $ 0.72 $ 0.56 Anti-dilutive warrants and stock options 9,350 70,266 1,850 70,266

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Schedule of Unfunded Commitments	Unfunded commitments are as follows: June 30, 2019 December 31, 2018 (Dollars in thousands) Unfunded loan commitments $ 211,064 $ 176,156 Commercial and standby letters of credit 1,088 547 Total $ 212,152 $ 176,703

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis	The following table presents the assets and liabilities measured at fair value on a recurring basis: June 30, 2019 Level 1 Level 2 Level 3 Total (Dollars in thousands) Assets: U.S. Treasury securities $ 32,536 $ — $ — $ 32,536 U.S. Government agencies — 4,121 — 4,121 State and municipal obligations — 25,418 — 25,418 Residential mortgage-backed securities — 103,303 — 103,303 Corporate bonds and other debt securities — 5,680 — 5,680 SBA servicing rights — — 3,570 3,570 Total $ 32,536 $ 138,522 $ 3,570 $ 174,628 December 31, 2018 Level 1 Level 2 Level 3 Total (Dollars in thousands) Assets: U.S. Government agencies $ — $ 1,934 $ — $ 1,934 State and municipal obligations — 18,048 — 18,048 Residential mortgage-backed securities — 153,974 — 153,974 Corporate bonds and other debt securities — 5,505 — 5,505 SBA servicing rights — — 3,965 3,965 Total $ — $ 179,461 $ 3,965 $ 183,426
Schedule of Assets Measured at Fair Value on Non-Recurring Basis	The following tables provide information about certain assets measured at fair value on a non-recurring basis: Estimated Fair Value June 30, 2019 December 31, 2018 (Dollars in thousands) Assets (classified in Level 3): Impaired loans $ 3,117 $ 2,696 Other real estate and repossessed assets 1,324 782
Significant Unobservable Inputs Used in Recurring and Non-Recurring Fair Value Measurements	The following tables show significant unobservable inputs used in the recurring and non-recurring fair value measurements of Level 3 assets: Level 3 Asset Fair Value Valuation Technique Unobservable Inputs Range/Weighted Average June 30, 2019 Non-recurring: Impaired loans $ 3,117 Third party appraisals Collateral discounts 0.0% - 100.0% (20.9%) Other real estate owned 1,324 Third party appraisals Collateral discounts and estimated cost to sell 10.0 % Recurring: SBA servicing assets 3,570 Discounted cash flows Conditional prepayment rate 12.7 % Discount rate 11.5 % December 31, 2018 Non-recurring: Impaired loans $ 2,696 Third party appraisals Collateral discounts 0.0% - 100.0% (19.2%) Other real estate owned 782 Third party appraisals Collateral discounts and estimated cost to sell 10.0 % Recurring: SBA servicing assets 3,965 Discounted cash flows Conditional prepayment rate 11.8 % Discount rate 11.5 %
Summary of Carrying Amounts and Estimated Fair Values of Financial Instruments	The carrying amounts and estimated fair values, as well as the level within the fair value hierarchy, of the Company’s financial instruments are as follows: June 30, 2019 Carrying Value Fair Value Level 1 Level 2 Level 3 (Dollars in thousands) Financial Assets: Cash and cash equivalents $ 163,158 $ 163,158 $ 163,158 $ — $ — Time deposits in other banks 1,225 1,225 1,225 Available for sale securities 171,058 171,058 32,536 138,522 — FHLB and other bank stock 6,190 6,190 — 6,190 — Loans, net 1,403,061 1,397,245 — — 1,397,245 Loans held for sale 2,583 2,801 — 2,801 — Accrued interest receivable 7,039 7,039 — 7,039 — Bank-owned life insurance 15,432 15,432 — 15,432 — SBA servicing rights 3,570 3,570 — — 3,570 Financial Liabilities: Deposits $ 1,570,604 $ 1,532,821 $ — $ 1,532,821 $ — Accrued interest payable 1,134 1,134 — 1,134 — Long-term borrowings 80,525 77,543 — 77,543 — December 31, 2018 Carrying Value Fair Value Level 1 Level 2 Level 3 (Dollars in thousands) Financial Assets: Cash and cash equivalents $ 89,015 $ 89,015 $ 89,015 $ — $ — Available for sale securities 179,461 179,461 — 179,461 — FHLB and other bank stock 5,304 5,304 — 5,304 — Loans, net 1,086,654 1,075,252 — — 1,075,252 Loans held for sale 3,945 4,200 — 4,200 — Accrued interest receivable 4,934 4,934 — 4,934 — Bank-owned life insurance 7,401 7,401 — 7,401 — SBA servicing rights 3,965 3,965 — — 3,965 Financial Liabilities: Deposits $ 1,182,648 $ 1,181,606 $ — $ 1,181,606 $ — Accrued interest payable 702 702 — 702 — Short-term borrowings 12,500 12,500 — 12,500 — Long-term borrowings 67,916 66,735 — 66,735 —

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	May 04, 2018	Jun. 30, 2018	Jun. 30, 2018
Subsidiary Sale Of Stock [Line Items]
Net proceeds from initial public offering			$ 42,219
Common Stock
Subsidiary Sale Of Stock [Line Items]
Number of shares issued and sold		2,300,000	2,300,000
Common Stock | Initial Public Offering
Subsidiary Sale Of Stock [Line Items]
Number of shares issued and sold	2,300,000
Stock issued, price per share	$ 21
Gross proceeds before deducting underwriting discounts and offering expenses	$ 48,300
Net proceeds from initial public offering	$ 42,100
Common Stock | Underwriters
Subsidiary Sale Of Stock [Line Items]
Number of shares issued and sold	300,000

Revenue Recognition - Schedule

Revenue Recognition - Schedule of Non-Interest Income, Segregated by Revenue Streams in-Scope and Out-of-Scope of Topic 606 (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Noninterest income:
Non-Interest Income	$ 3,775	$ 2,303	$ 6,832	$ 4,891
Accounting Standards Update 2014-09
Noninterest income:
Non-Interest Income (in-scope of Topic 606)	1,176	630	2,029	1,148
Out-of-scope of Topic 606
Noninterest income:
Non-Interest Income	2,599	1,673	4,803	3,743
Deposit accounts core service charges | Accounting Standards Update 2014-09
Noninterest income:
Non-Interest Income (in-scope of Topic 606)	149	78	261	145
Deposit account transaction based fee income | Accounting Standards Update 2014-09
Noninterest income:
Non-Interest Income (in-scope of Topic 606)	829	344	1,460	639
Mortgage referral fees | Accounting Standards Update 2014-09
Noninterest income:
Non-Interest Income (in-scope of Topic 606)	$ 198	$ 208	$ 308	$ 364

Business Combinations - Additio

Business Combinations - Additional Information (Details) $ in Thousands	Apr. 02, 2019USD ($)Branchofficeshares	Nov. 14, 2018USD ($)Branchshares	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Business Acquisition [Line Items]
Goodwill			$ 43,889		$ 43,889		$ 18,253	$ 4,485
Comanche National Corporation
Business Acquisition [Line Items]
Business acquisition date					Nov. 14, 2018
Business acquisition, shares issued | shares		2,142,811
Business acquisition, cash paid		$ 12,246
Business acquisition, total consideration		$ 52,900
Acquired ownership interest		100.00%
Goodwill		$ 13,768
Acquisition expenses			0	$ 0	$ 1,200	$ 0
Non-credit impaired loans fair value		116,200
Contractual balance		117,200
Interest income		$ 946
Comanche National Corporation | North/South Texas
Business Acquisition [Line Items]
Number of additional branches | Branch		8
First Beeville Financial Corporation
Business Acquisition [Line Items]
Business acquisition date					Apr. 2, 2019
Business acquisition, shares issued | shares	1,579,191
Business acquisition, cash paid	$ 32,375
Business acquisition, total consideration	$ 65,900
Acquired ownership interest	100.00%
Goodwill	$ 25,636
Acquisition expenses			1,200	$ 0	$ 1,700	$ 0
Non-credit impaired loans fair value	296,300
Contractual balance	298,900
Interest income	$ 2,600
Revenue of acquiree since acquisition date			5,200
Earnings of acquiree since acquisition date			$ 2,600
First Beeville Financial Corporation | North/South Texas
Business Acquisition [Line Items]
Number of additional branches | Branch	3
Number of loan production offices | office	2

Business Combinations - Fair Va

Business Combinations - Fair Value of Asset Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Apr. 02, 2019	Nov. 14, 2018	Jun. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill			$ 43,889	$ 18,253	$ 4,485
Comanche National Corporation
Business Acquisition [Line Items]
Cash and cash equivalents		$ 57,135
Securities available for sale		144,735
Loans held for investment		116,220
Premises and equipment, net		6,634
Other real estate owned		33
Goodwill		13,768
Core deposit intangible		5,988
Other assets		11,712
Total assets acquired		356,225
Deposits		297,778
Trust preferred securities		2,811
Other liabilities		2,698
Total liabilities assumed		303,287
Common stock issued		40,692
Business acquisition, cash paid		$ 12,246
First Beeville Financial Corporation
Business Acquisition [Line Items]
Cash and cash equivalents	$ 60,941
Securities available for sale	57,206
Loans held for investment	296,348
Premises and equipment, net	6,067
Other real estate owned	1,359
Goodwill	25,636
Core deposit intangible	5,635
Other assets	12,860
Total assets acquired	466,052
Deposits	399,654
Other liabilities	543
Total liabilities assumed	400,197
Common stock issued	33,480
Business acquisition, cash paid	$ 32,375

Business Combinations - Fair _2

Business Combinations - Fair Value of Asset Acquired and Liabilities Assumed (Parenthetical) (Details) - Common Stock - $ / shares	Apr. 02, 2019	Nov. 14, 2018
Comanche National Corporation
Business Acquisition [Line Items]
Shares issued, price per share		$ 18.99
First Beeville Financial Corporation
Business Acquisition [Line Items]
Shares issued, price per share	$ 21.20

Investment Securities - Schedul

Investment Securities - Schedule of Fair Values of Securities Available for Sale (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Schedule Of Available For Sale Securities [Line Items]
Securities available for sale, Amortized Cost	$ 169,405	$ 177,115
Securities available for sale, Unrealized Gains	2,843	3,461
Securities available for sale, Unrealized Losses	1,190	1,115
Available for sale securities, at fair value	171,058	179,461
U.S. Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Securities available for sale, Amortized Cost	32,537
Securities available for sale, Unrealized Gains	3
Securities available for sale, Unrealized Losses	4
Available for sale securities, at fair value	32,536
U.S. Government Agencies
Schedule Of Available For Sale Securities [Line Items]
Securities available for sale, Amortized Cost	4,084	2,015
Securities available for sale, Unrealized Gains	37
Securities available for sale, Unrealized Losses		81
Available for sale securities, at fair value	4,121	1,934
State and Municipal Obligations
Schedule Of Available For Sale Securities [Line Items]
Securities available for sale, Amortized Cost	24,988	17,201
Securities available for sale, Unrealized Gains	459	847
Securities available for sale, Unrealized Losses	29
Available for sale securities, at fair value	25,418	18,048
Residential Mortgage-backed Securities
Schedule Of Available For Sale Securities [Line Items]
Securities available for sale, Amortized Cost	102,151	152,232
Securities available for sale, Unrealized Gains	2,306	2,614
Securities available for sale, Unrealized Losses	1,154	872
Available for sale securities, at fair value	103,303	153,974
Corporate Bonds and Other Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Securities available for sale, Amortized Cost	5,645	5,667
Securities available for sale, Unrealized Gains	38
Securities available for sale, Unrealized Losses	3	162
Available for sale securities, at fair value	$ 5,680	$ 5,505

Investment Securities - Additio

Investment Securities - Additional Information (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)Security	Jun. 30, 2018USD ($)Security	Jun. 30, 2019USD ($)Security	Jun. 30, 2018USD ($)Security	Dec. 31, 2018USD ($)
Investments Debt And Equity Securities [Abstract]
Taxable interest and dividends on investment securities	$ 1,100,000	$ 195,000	$ 2,200,000	$ 409,000
Tax-exempt interest on investment securities	163,000	$ 0	271,000	$ 0
Available for sale securities pledged	$ 145,100,000		$ 145,100,000		$ 106,600,000
Debt Securities, Available-for-sale, Restriction Type [Extensible List]	us-gaap:CollateralPledgedMember		us-gaap:CollateralPledgedMember		us-gaap:CollateralPledgedMember
Available for sale, securities number of positions | Security	229		229
Available for sale, securities in unrealized loss positions, number of positions | Security	69		69
Available for sale, securities in unrealized loss positions, number of positions, more than 12 months | Security	64		64
Available for sale securities, gross realized gain (loss), excluding other than temporary impairments			$ 0
Sales of investment securities available for sale	$ 34,700,000		79,920,000
Gross realized gains	$ 1,100,000		$ 2,100,000
Number of securities sold | Security		0		0

Investment Securities - Sched_2

Investment Securities - Schedule of Securities Available for Sale by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Available for sale:
Due in one year or less, Amortized Cost	$ 9,695
Due after one year through five years, Amortized Cost	43,470
Due after five years through ten years, Amortized Cost	8,417
Due after ten years, Amortized Cost	5,672
Total available for sale, Amortized Cost	169,405	$ 177,115
Available for sale:
Due in one year or less, Fair Value	9,690
Due after one year through five years. Fair Value	43,535
Due after five years through ten years. Fair Value	8,459
Due after ten years. Fair Value	6,071
Total available for sale, Fair Value	171,058	179,461
Residential Mortgage-backed Securities
Available for sale:
Total available for sale, Amortized Cost	102,151	152,232
Available for sale:
Total available for sale, Fair Value	$ 103,303	$ 153,974

Investment Securities - Sched_3

Investment Securities - Schedule of Investment Securities Available for Sale and Aggregated by Investment Category and Length of Time Individual Securities in Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Schedule Of Available For Sale Securities [Line Items]
Investment Securities, Available for sale, Fair Value, Less than 12 Months	$ 14,447	$ 1
Investment Securities, Available for sale, Unrealized Loss, Less than 12 Months	4
Investment Securities, Available for sale, Fair Value, 12 Months or More	39,019	32,918
Investment Securities, Available for sale, Unrealized Loss, 12 Months or More	1,186	1,115
Investment Securities, Available for sale, Fair Value	53,466	32,919
Investment Securities, Available for sale, Unrealized Loss	1,190	1,115
U.S. Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Investment Securities, Available for sale, Fair Value, Less than 12 Months	14,447
Investment Securities, Available for sale, Unrealized Loss, Less than 12 Months	4
Investment Securities, Available for sale, Fair Value	14,447
Investment Securities, Available for sale, Unrealized Loss	4
U.S. Government Agencies
Schedule Of Available For Sale Securities [Line Items]
Investment Securities, Available for sale, Fair Value, 12 Months or More		1,934
Investment Securities, Available for sale, Unrealized Loss, 12 Months or More		81
Investment Securities, Available for sale, Fair Value		1,934
Investment Securities, Available for sale, Unrealized Loss		81
State and Municipal Obligations
Schedule Of Available For Sale Securities [Line Items]
Investment Securities, Available for sale, Fair Value, 12 Months or More	11,014
Investment Securities, Available for sale, Unrealized Loss, 12 Months or More	29
Investment Securities, Available for sale, Fair Value	11,014
Investment Securities, Available for sale, Unrealized Loss	29
Residential Mortgage-backed Securities
Schedule Of Available For Sale Securities [Line Items]
Investment Securities, Available for sale, Fair Value, Less than 12 Months		1
Investment Securities, Available for sale, Fair Value, 12 Months or More	26,009	25,479
Investment Securities, Available for sale, Unrealized Loss, 12 Months or More	1,154	872
Investment Securities, Available for sale, Fair Value	26,009	25,480
Investment Securities, Available for sale, Unrealized Loss	1,154	872
Corporate Bonds and Other Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Investment Securities, Available for sale, Fair Value, 12 Months or More	1,996	5,505
Investment Securities, Available for sale, Unrealized Loss, 12 Months or More	3	162
Investment Securities, Available for sale, Fair Value	1,996	5,505
Investment Securities, Available for sale, Unrealized Loss	$ 3	$ 162

Loans, Net - Summary of Loans (

Loans, Net - Summary of Loans (Details) - USD ($) $ in Thousands		Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Total loans held in portfolio	[1]	$ 1,409,338		$ 1,092,940
Allowance for loan losses		(6,277)	$ (6,569)	(6,286)	$ (6,015)	$ (5,727)	$ (5,652)
Loans, net		1,403,061		1,086,654
Commercial and Industrial Loans
Accounts Notes And Loans Receivable [Line Items]
Total loans held in portfolio	[2]	197,774		173,892
Consumer Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Total loans held in portfolio		20,745		24,378
Municipal and Other Loans
Accounts Notes And Loans Receivable [Line Items]
Total loans held in portfolio		69,711		61,339
Real Estate | 1-4 Single Family Residential Loans
Accounts Notes And Loans Receivable [Line Items]
Total loans held in portfolio		277,560		275,644
Real Estate | Construction, Land and Development
Accounts Notes And Loans Receivable [Line Items]
Total loans held in portfolio		176,567		159,734
Real Estate | Commercial Real Estate Loans (Including Multifamily)
Accounts Notes And Loans Receivable [Line Items]
Total loans held in portfolio		$ 666,981		$ 397,953
[1]	Balance includes $(8.1) million and $(4.9) million of deferred fees, cost, premium and discount as of June 30, 2019 and December 31, 2018, respectively.
[2]	Balance includes $71.3 million and $76.9 million of the unguaranteed portion of SBA loans as of June 30, 2019 and December 31, 2018, respectively.

Loans, Net - Summary of Loans_2

Loans, Net - Summary of Loans (Parenthetical) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Accounts Notes And Loans Receivable [Line Items]
Deferred fees, cost, premium and discount	$ (8.1)	$ (4.9)
SBA Loans
Accounts Notes And Loans Receivable [Line Items]
Unguaranteed portion of loans	$ 71.3	$ 76.9

Loans, Net - Additional Informa

Loans, Net - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Accounts Notes And Loans Receivable [Line Items]
Pledged loans, collateral for FHLB advances	$ 516,400,000		$ 516,400,000		$ 385,500,000
Unfunded commitments to related parties	212,152,000		212,152,000		176,703,000
Executive Officers and Directors
Accounts Notes And Loans Receivable [Line Items]
Unfunded commitments to related parties	0		0		0
Consumer Mortgage Loans
Accounts Notes And Loans Receivable [Line Items]
Recorded mortgage loans in process of foreclosure	0		0		$ 0
SBA Loans | Third Party
Accounts Notes And Loans Receivable [Line Items]
Servicing loans sold	16,400,000	$ 12,900,000	26,500,000	$ 30,000,000
Realized gains on servicing loans sold	$ 1,400,000	$ 1,000,000	$ 2,200,000	$ 2,500,000

Loans, Net - Summary of Loans t

Loans, Net - Summary of Loans to Related Parties and Principal Owners (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Receivables [Abstract]
Principal outstanding, beginning of year	$ 93	$ 442	$ 107	$ 463
Additions (reductions) of affiliations	2,352		2,352
Repayments	(12)	(21)	(26)	(42)
Principal outstanding, end of year	$ 2,433	$ 421	$ 2,433	$ 421

Allowance for Loan and Lease _3

Allowance for Loan and Lease Losses - Additional Information (Details) $ in Thousands	Apr. 02, 2019USD ($)	Nov. 14, 2018USD ($)	Jun. 30, 2019USD ($)Loan	Dec. 31, 2018USD ($)Loan
Financing Receivable Recorded Investment Past Due [Line Items]
Amount of defaults Lookback period			5 years
Recorded investment, 90 days past due and still accruing				$ 288
Non-accrual loans, Past due			$ 5,725	$ 5,031
Financing Receivables, Past Due Greater Than 90 Days or More and Still Accruing
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, 90 days past due and still accruing number of loans | Loan			0	4
Non-accrual loans, Past due			$ 1,700	$ 2,000
Financing Receivables, 30 to 59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Non-accrual loans, Past due			38	175
Financing Receivables, 60 to 89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Non-accrual loans, Past due			$ 59	$ 143
Comanche
Financing Receivable Recorded Investment Past Due [Line Items]
Business combination loan in acquiree, amount		$ 117,200
Business combination loan In acquiree, fair value		116,200
Business combination loan in acquiree, discount		$ 946
Beeville
Financing Receivable Recorded Investment Past Due [Line Items]
Business combination loan in acquiree, amount	$ 298,900
Business combination loan In acquiree, fair value	296,300
Business combination loan in acquiree, discount	$ 2,600

Allowance for Loan and Lease _4

Allowance for Loan and Lease Losses - Allowance for Loan and Lease Losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Loans And Leases Receivable Disclosure [Line Items]
Beginning Balance	$ 6,569	$ 5,727	$ 6,286	$ 5,652
Charge-offs	(659)	(350)	(1,255)	(680)
Recoveries	35	3	65	69
Provision	332	635	1,181	974
Ending Balance	6,277	6,015	6,277	6,015
Commercial and Industrial Loans
Loans And Leases Receivable Disclosure [Line Items]
Beginning Balance	4,661	2,906	4,453	3,046
Charge-offs	(643)	(321)	(1,221)	(645)
Recoveries	31	3	59	69
Provision	168	2,298	926	2,416
Ending Balance	4,217	4,886	4,217	4,886
Real Estate | 1-4 Single Family Residential Loans
Loans And Leases Receivable Disclosure [Line Items]
Beginning Balance	34	887	59	902
Charge-offs		(5)		(5)
Provision	(2)	(564)	(27)	(579)
Ending Balance	32	318	32	318
Real Estate | Construction, Land and Development Loans
Loans And Leases Receivable Disclosure [Line Items]
Beginning Balance	749	540	731	441
Provision	45	(345)	63	(246)
Ending Balance	794	195	794	195
Real Estate | Commercial Real Estate Loans (Including Multifamily)
Loans And Leases Receivable Disclosure [Line Items]
Beginning Balance	1,057	1,032	960	898
Provision	134	(799)	231	(665)
Ending Balance	1,191	233	1,191	233
Consumer Loans and Leases
Loans And Leases Receivable Disclosure [Line Items]
Beginning Balance	57	175	80	198
Charge-offs	(16)	(24)	(34)	(30)
Recoveries	3		5
Provision	(9)	195	(16)	178
Ending Balance	35	346	35	346
Municipal and Other Loans
Loans And Leases Receivable Disclosure [Line Items]
Beginning Balance	11	187	3	167
Recoveries	1		1
Provision	(4)	(150)	4	(130)
Ending Balance	$ 8	$ 37	$ 8	$ 37

Allowance for Loan and Lease _5

Allowance for Loan and Lease Losses - Summary of Aging Analysis of Recorded Investment for Delinquent Loans by Portfolio and Segment (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Current	$ 1,399,310	$ 1,084,795
Recorded investment, Non-accrual	5,725	5,031
Recorded investment, Total	1,409,338	1,092,940
Financing Receivables, 30 to 59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Past due	2,999	1,906
Recorded investment, Non-accrual	38	175
Financing Receivables, 60 to 89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Past due	1,304	920
Recorded investment, Non-accrual	59	143
Financing Receivables, Past Due Greater Than 90 Days or More and Still Accruing
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Past due		288
Recorded investment, Non-accrual	1,700	2,000
Commercial and Industrial Loans
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Current	192,098	169,206
Recorded investment, Non-accrual	5,282	3,570
Recorded investment, Total	197,774	173,892
Commercial and Industrial Loans | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Past due	332	605
Commercial and Industrial Loans | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Past due	62	223
Commercial and Industrial Loans | Financing Receivables, Past Due Greater Than 90 Days or More and Still Accruing
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Past due		288
Real Estate | 1-4 Single Family Residential Loans
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Current	277,004	273,909
Recorded investment, Non-accrual	208	1,090
Recorded investment, Total	277,560	275,644
Real Estate | 1-4 Single Family Residential Loans | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Past due	303	581
Real Estate | 1-4 Single Family Residential Loans | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Past due	45	64
Real Estate | Construction, Land and Development
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Current	174,373	159,723
Recorded investment, Total	176,567	159,734
Real Estate | Construction, Land and Development | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Past due	2,194	11
Real Estate | Commercial Real Estate Loans (Including Multifamily)
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Current	665,764	396,559
Recorded investment, Non-accrual	136	354
Recorded investment, Total	666,981	397,953
Real Estate | Commercial Real Estate Loans (Including Multifamily) | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Past due	13	451
Real Estate | Commercial Real Estate Loans (Including Multifamily) | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Past due	1,068	589
Consumer Loans and Leases
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Current	20,495	24,109
Recorded investment, Non-accrual	46	17
Recorded investment, Total	20,745	24,378
Consumer Loans and Leases | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Past due	157	208
Consumer Loans and Leases | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Past due	47	44
Municipal and Other Loans
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Current	69,576	61,289
Recorded investment, Non-accrual	53
Recorded investment, Total	69,711	61,339
Municipal and Other Loans | Financing Receivables, 30 to 59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Past due		$ 50
Municipal and Other Loans | Financing Receivables, 60 to 89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Recorded investment, Accruing, Past due	$ 82

Allowance for Loan and Lease _6

Allowance for Loan and Lease Losses - Summary of Loans by Key Indicators of Credit Quality (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 1,409,338	$ 1,092,940
Pass
Financing Receivable Recorded Investment [Line Items]
Total loans	1,394,591	1,057,393
Special Mention
Financing Receivable Recorded Investment [Line Items]
Total loans	6,987	19,640
Substandard
Financing Receivable Recorded Investment [Line Items]
Total loans	7,760	13,156
Doubtful
Financing Receivable Recorded Investment [Line Items]
Total loans		2,751
Commercial and Industrial Loans
Financing Receivable Recorded Investment [Line Items]
Total loans	197,774	173,892
Commercial and Industrial Loans | Pass
Financing Receivable Recorded Investment [Line Items]
Total loans	191,854	163,908
Commercial and Industrial Loans | Special Mention
Financing Receivable Recorded Investment [Line Items]
Total loans	2,812	3,170
Commercial and Industrial Loans | Substandard
Financing Receivable Recorded Investment [Line Items]
Total loans	3,108	6,601
Commercial and Industrial Loans | Doubtful
Financing Receivable Recorded Investment [Line Items]
Total loans		213
Real Estate | 1-4 Single Family Residential Loans
Financing Receivable Recorded Investment [Line Items]
Total loans	277,560	275,644
Real Estate | 1-4 Single Family Residential Loans | Pass
Financing Receivable Recorded Investment [Line Items]
Total loans	276,076	270,839
Real Estate | 1-4 Single Family Residential Loans | Special Mention
Financing Receivable Recorded Investment [Line Items]
Total loans	951	1,714
Real Estate | 1-4 Single Family Residential Loans | Substandard
Financing Receivable Recorded Investment [Line Items]
Total loans	533	2,547
Real Estate | 1-4 Single Family Residential Loans | Doubtful
Financing Receivable Recorded Investment [Line Items]
Total loans		544
Real Estate | Construction, Land and Development
Financing Receivable Recorded Investment [Line Items]
Total loans	176,567	159,734
Real Estate | Construction, Land and Development | Pass
Financing Receivable Recorded Investment [Line Items]
Total loans	175,610	157,688
Real Estate | Construction, Land and Development | Special Mention
Financing Receivable Recorded Investment [Line Items]
Total loans	10	24
Real Estate | Construction, Land and Development | Substandard
Financing Receivable Recorded Investment [Line Items]
Total loans	947	2,022
Real Estate | Commercial Real Estate Loans (Including Multifamily)
Financing Receivable Recorded Investment [Line Items]
Total loans	666,981	397,953
Real Estate | Commercial Real Estate Loans (Including Multifamily) | Pass
Financing Receivable Recorded Investment [Line Items]
Total loans	660,606	383,323
Real Estate | Commercial Real Estate Loans (Including Multifamily) | Special Mention
Financing Receivable Recorded Investment [Line Items]
Total loans	3,214	12,412
Real Estate | Commercial Real Estate Loans (Including Multifamily) | Substandard
Financing Receivable Recorded Investment [Line Items]
Total loans	3,161	1,806
Real Estate | Commercial Real Estate Loans (Including Multifamily) | Doubtful
Financing Receivable Recorded Investment [Line Items]
Total loans		412
Consumer Loans and Leases
Financing Receivable Recorded Investment [Line Items]
Total loans	20,745	24,378
Consumer Loans and Leases | Pass
Financing Receivable Recorded Investment [Line Items]
Total loans	20,734	20,798
Consumer Loans and Leases | Special Mention
Financing Receivable Recorded Investment [Line Items]
Total loans		1,836
Consumer Loans and Leases | Substandard
Financing Receivable Recorded Investment [Line Items]
Total loans	11	180
Consumer Loans and Leases | Doubtful
Financing Receivable Recorded Investment [Line Items]
Total loans		1,564
Municipal and Other Loans
Financing Receivable Recorded Investment [Line Items]
Total loans	69,711	61,339
Municipal and Other Loans | Pass
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 69,711	60,837
Municipal and Other Loans | Special Mention
Financing Receivable Recorded Investment [Line Items]
Total loans		484
Municipal and Other Loans | Doubtful
Financing Receivable Recorded Investment [Line Items]
Total loans		$ 18

Allowance for Loan and Lease _7

Allowance for Loan and Lease Losses - Summary of Investment in Loans Disaggregated Based on Method of Evaluating Impairment (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable Allowance For Credit Losses [Line Items]
Loans - Recorded Investment, Individually Evaluated for Impairment	$ 5,660	$ 4,850
Loans - Recorded Investment, Collectively Evaluated for Impairment	1,403,678	1,088,090
Allowance for Credit Loss, Individually Evaluated for Impairment	1,626	1,267
Allowance for Credit Loss, Collectively Evaluated for Impairment	4,651	5,019
Commercial and Industrial Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans - Recorded Investment, Individually Evaluated for Impairment	3,783	3,640
Loans - Recorded Investment, Collectively Evaluated for Impairment	193,991	170,252
Allowance for Credit Loss, Individually Evaluated for Impairment	1,618	1,234
Allowance for Credit Loss, Collectively Evaluated for Impairment	2,599	3,219
Real Estate | 1-4 Single Family Residential Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans - Recorded Investment, Individually Evaluated for Impairment	1,401	1,193
Loans - Recorded Investment, Collectively Evaluated for Impairment	276,159	274,451
Allowance for Credit Loss, Individually Evaluated for Impairment	4	29
Allowance for Credit Loss, Collectively Evaluated for Impairment	28	30
Real Estate | Construction, Land and Development
Financing Receivable Allowance For Credit Losses [Line Items]
Loans - Recorded Investment, Individually Evaluated for Impairment	219
Loans - Recorded Investment, Collectively Evaluated for Impairment	176,348	159,734
Allowance for Credit Loss, Collectively Evaluated for Impairment	794	731
Real Estate | Commercial Real Estate Loans (Including Multifamily)
Financing Receivable Allowance For Credit Losses [Line Items]
Loans - Recorded Investment, Individually Evaluated for Impairment	241
Loans - Recorded Investment, Collectively Evaluated for Impairment	666,740	397,953
Allowance for Credit Loss, Collectively Evaluated for Impairment	1,191	960
Consumer Loans and Leases
Financing Receivable Allowance For Credit Losses [Line Items]
Loans - Recorded Investment, Individually Evaluated for Impairment	16	17
Loans - Recorded Investment, Collectively Evaluated for Impairment	20,729	24,361
Allowance for Credit Loss, Individually Evaluated for Impairment	4	4
Allowance for Credit Loss, Collectively Evaluated for Impairment	31	76
Municipal and Other Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Loans - Recorded Investment, Collectively Evaluated for Impairment	69,711	61,339
Allowance for Credit Loss, Collectively Evaluated for Impairment	$ 8	$ 3

Allowance for Loan and Lease _8

Allowance for Loan and Lease Losses - Summary of Information Regarding Impaired Loans Evaluated for Specific Reserves (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Financing Receivable Impaired [Line Items]
Impaired Loans - With Allowance, Recorded Investment	$ 3,292		$ 3,292		$ 1,976
Impaired Loans - With Allowance, Unpaid Principal Balance	6,666		6,666		5,533
Impaired Loans - With Allowance, Related Allowance	1,626		1,626		1,267
Impaired Loans - With no Allowance, Recorded Investment	2,368		2,368		2,874
Impaired Loans - With no Allowance, Unpaid Principal Balance	5,221		5,221		4,586
Average Recorded Investment	5,452	$ 4,220	5,576	$ 4,417
Commercial and Industrial Loans
Financing Receivable Impaired [Line Items]
Impaired Loans - With Allowance, Recorded Investment	3,124		3,124		1,843
Impaired Loans - With Allowance, Unpaid Principal Balance	6,490		6,490		5,392
Impaired Loans - With Allowance, Related Allowance	1,618		1,618		1,234
Impaired Loans - With no Allowance, Recorded Investment	659		659		1,797
Impaired Loans - With no Allowance, Unpaid Principal Balance	3,170		3,170		3,500
Average Recorded Investment	3,691	2,435	3,797	2,620
Real Estate | 1-4 Single Family Residential Loans
Financing Receivable Impaired [Line Items]
Impaired Loans - With Allowance, Recorded Investment	152		152		116
Impaired Loans - With Allowance, Unpaid Principal Balance	160		160		124
Impaired Loans - With Allowance, Related Allowance	4		4		29
Impaired Loans - With no Allowance, Recorded Investment	1,249		1,249		1,077
Impaired Loans - With no Allowance, Unpaid Principal Balance	1,582		1,582		1,086
Average Recorded Investment	1,282	1,511	1,295	1,518
Real Estate | Construction, Land and Development
Financing Receivable Impaired [Line Items]
Impaired Loans - With no Allowance, Recorded Investment	219		219
Impaired Loans - With no Allowance, Unpaid Principal Balance	223		223
Average Recorded Investment	220	24	222	25
Real Estate | Commercial Real Estate Loans (Including Multifamily)
Financing Receivable Impaired [Line Items]
Impaired Loans - With no Allowance, Recorded Investment	241		241
Impaired Loans - With no Allowance, Unpaid Principal Balance	246		246
Average Recorded Investment	243	149	245	151
Consumer Loans and Leases
Financing Receivable Impaired [Line Items]
Impaired Loans - With Allowance, Recorded Investment	16		16		17
Impaired Loans - With Allowance, Unpaid Principal Balance	16		16		17
Impaired Loans - With Allowance, Related Allowance	4		4		$ 4
Average Recorded Investment	$ 16	$ 101	$ 17	$ 103

Allowance for Loan and Lease _9

Allowance for Loan and Lease Losses - Summary of Troubled Debt Restructurings (TDRs) Based Upon Delinquency Status (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019USD ($)Contract	Jun. 30, 2018Contract	Jun. 30, 2019USD ($)Contract	Jun. 30, 2018Contract	Dec. 31, 2018USD ($)Contract
Financing Receivable Modifications [Line Items]
Number of contracts			14		12
Recorded Investment | $	$ 709		$ 709		$ 658
Allowance attributable to TDRs | $	$ 224		$ 224		$ 149
Commercial and Industrial Loans
Financing Receivable Modifications [Line Items]
Number of contracts	3	2	3	7
Real Estate | 1-4 Single Family Residential Loans
Financing Receivable Modifications [Line Items]
Number of contracts		1		1
Performing TDRs
Financing Receivable Modifications [Line Items]
Number of contracts			5		5
Recorded Investment | $	$ 254		$ 254		$ 210
Performing TDRs | Commercial and Industrial Loans
Financing Receivable Modifications [Line Items]
Number of contracts			3		3
Recorded Investment | $	122		$ 122		$ 69
Performing TDRs | Real Estate | 1-4 Single Family Residential Loans
Financing Receivable Modifications [Line Items]
Number of contracts			2		2
Recorded Investment | $	132		$ 132		$ 141
Nonperforming TDRs
Financing Receivable Modifications [Line Items]
Number of contracts			9		7
Recorded Investment | $	$ 455		$ 455		$ 448

Allowance for Loan and Lease_10

Allowance for Loan and Lease Losses - Summary of TDRs Includes Newly Designated TDRs and Modifications to Existing TDRs (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019USD ($)Contract	Jun. 30, 2018USD ($)Contract	Jun. 30, 2019USD ($)Contract	Jun. 30, 2018USD ($)Contract	Dec. 31, 2018Contract
Financing Receivable Modifications [Line Items]
Number of contracts | Contract			14		12
Commercial and Industrial Loans
Financing Receivable Modifications [Line Items]
Number of contracts | Contract	3	2	3	7
Pre-Modification Outstanding Recorded Investment	$ 185	$ 73	$ 185	$ 442
Post-Modification Outstanding Recorded Investment	185	73	185	442
Related Allowance	$ 88	$ 53	$ 88	$ 192
Real Estate | 1-4 Single Family Residential Loans
Financing Receivable Modifications [Line Items]
Number of contracts | Contract		1		1
Pre-Modification Outstanding Recorded Investment		$ 34		$ 34
Post-Modification Outstanding Recorded Investment		$ 34		$ 34

Goodwill and Intangibles - Sche

Goodwill and Intangibles - Schedule of Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Beginning goodwill	$ 18,253	$ 4,485
Arising from business combination	25,636	13,768
Ending goodwill	43,889	18,253
Core deposit intangible	8,558	13,166
Arising from business combination	10,244
Less: Accumulated amortization	(6,219)	(4,608)
Core deposit intangible, net	$ 12,583	$ 8,558

Goodwill and Intangibles - Addi

Goodwill and Intangibles - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Finite Lived Intangible Assets [Line Items]
Amortization expense	$ 1,006	$ 175	$ 1,609	$ 351
Core Deposit Intangible
Finite Lived Intangible Assets [Line Items]
Amortization expense	$ 1,000	$ 175	$ 1,600	$ 351

Goodwill and Intangibles - Sc_2

Goodwill and Intangibles - Schedule of Estimated Amortization Expense for Intangible Assets (Details) - Core Deposit Intangible $ in Thousands	Jun. 30, 2019USD ($)
Finite Lived Intangible Assets [Line Items]
Remainder of 2019	$ 1,977
2020	3,503
2021	2,852
2022	2,063
2023	1,378
2024	$ 649

SBA Servicing Asset - Additiona

SBA Servicing Asset - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Transfers And Servicing Of Financial Assets [Abstract]
Unpaid principal balances of loans serviced	$ 213,500		$ 213,500		$ 225,000
Loan expenses	$ 40	$ 548	$ 304	$ 1,200

SBA Servicing Asset - Summary o

SBA Servicing Asset - Summary of Activity Pertaining to SBA Servicing Rights (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Transfers And Servicing Of Financial Assets [Abstract]
Beginning balance	$ 3,747	$ 3,512	$ 3,965	$ 3,411
Origination of servicing assets	322	247	520	579
Change in fair value:
Due to run-off	(239)	(245)	(404)	(453)
Due to market changes	(260)	7	(511)	(16)
Ending balance	$ 3,570	$ 3,521	$ 3,570	$ 3,521

Deposits - Summary of Deposits

Deposits - Summary of Deposits by Category (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Banking And Thrift [Abstract]
Noninterest-bearing demand deposits	$ 367,892	$ 256,784
Interest-bearing demand deposits	292,550	124,933
Interest-bearing NOW accounts	7,638	7,961
Savings and money market accounts	269,651	245,928
Time deposits	632,873	547,042
Total deposits	1,570,604	1,182,648
Time deposits $100,000 and greater	500,044	422,447
Time deposits $250,000 and greater	177,235	129,424
Related party deposits (executive officers and directors)	$ 11,956	$ 7,847

Deposits - Additional Informati

Deposits - Additional Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Banking And Thrift [Abstract]
Aggregate amount of overdraft demand deposits reclassified to loans	$ 94	$ 93
Aggregate amount of maturities for time deposits, period	5 years
Aggregate amount of maturities for time deposits, year one	$ 505,900
Aggregate amount of maturities for time deposits, year two	92,000
Aggregate amount of maturities for time deposits, year three	15,800
Aggregate amount of maturities for time deposits, year four	13,100
Aggregate amount of maturities for time deposits, year five	$ 6,100

Stock-Based Compensation and _3

Stock-Based Compensation and Other Benefit Plans - Summary of Option Activity (Details) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2019USD ($)$ / sharesshares
2008 Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options, Outstanding | shares	1,116,672
Options, Exercised | shares	(91,550)
Options, Forfeited | shares	(3,000)
Options, Outstanding | shares	1,022,122
Options, Vested and exercisable | shares	889,102
Weighted Average Exercise Price, Outstanding | $ / shares	$ 13.04
Weighted Average Exercise Price, Exercised | $ / shares	12.01
Weighted Average Exercise Price, Forfeited | $ / shares	16
Weighted Average Exercise Price, Outstanding | $ / shares	13.13
Weighted Average Exercise Price, Vested and exercisable | $ / shares	$ 12.94
Aggregate Intrinsic Value, Exercised | $	$ 960
Aggregate Intrinsic Value, Outstanding | $	9,577
Vested and exercisable at June 30, 2019 | $	$ 8,500
Weighted Average Remaining Contractual Life (Years), Outstanding	4 years 6 months 18 days
Weighted Average Remaining Contractual Life (Years), Vested and Exercisable	4 years 3 months 3 days
2017 Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options, Outstanding | shares	205,725
Options, Granted | shares	850
Options, Exercised | shares	(5,000)
Options, Outstanding | shares	201,575
Options, Vested and exercisable | shares	89,379
Weighted Average Exercise Price, Outstanding | $ / shares	$ 17.45
Weighted Average Exercise Price, Granted | $ / shares	23.18
Weighted Average Exercise Price, Exercised | $ / shares	15
Weighted Average Exercise Price, Outstanding | $ / shares	17.53
Weighted Average Exercise Price, Vested and exercisable | $ / shares	$ 15.95
Aggregate Intrinsic Value, Granted | $	$ 1
Aggregate Intrinsic Value, Exercised | $	38
Aggregate Intrinsic Value, Outstanding | $	1,002
Vested and exercisable at June 30, 2019 | $	$ 585
Weighted Average Remaining Contractual Life (Years), Outstanding	8 years 2 months 15 days
Weighted Average Remaining Contractual Life (Years), Vested and Exercisable	7 years 10 months 9 days

Stock-Based Compensation and _4

Stock-Based Compensation and Other Benefit Plans - Additional Information (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019USD ($)shares	Jun. 30, 2019USD ($)shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option activity | shares	0	0
2008 Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unrecognized compensation cost	$ 426	$ 426
Compensation cost recognized weighted average remaining period		1 year 6 months
2017 Stock Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unrecognized compensation cost	605	$ 605
Compensation cost recognized weighted average remaining period		3 years 7 months 13 days
2017 Stock Plan | Restricted Stock Unit Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unrecognized compensation cost	$ 409	$ 409
Compensation cost recognized weighted average remaining period		4 years 9 months 25 days
Restricted stock units granted | shares		19,500
Fair value of restricted stock		$ 424

Stock-Based Compensation and _5

Stock-Based Compensation and Other Benefit Plans - Summary of Assumptions Used to Calculated Fair Value Utilizing Black-Scholes Pricing Model (Details) - 2017 Stock Plan	6 Months Ended
	Jun. 30, 2019$ / shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility	23.30%
Expected dividend yield	0.00%
Expected term (years)	7 years 6 months
Risk-free interest rate, minimum	2.58%
Weighted average grant date fair value	$ 7.57

Stock-Based Compensation and _6

Stock-Based Compensation and Other Benefit Plans - Summary of Activity Related to Restricted Stock Units (Details) - 2017 Stock Plan - Restricted Stock Unit Awards	6 Months Ended
	Jun. 30, 2019$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares, Granted | shares	19,500
Shares, Outstanding, Beginning balance | shares	19,500
Weighted-Average Grant Date Fair Value, Granted | $ / shares	$ 21.75
Weighted-Average Grant Date Fair Value, Outstanding | $ / shares	$ 21.75

Stock Based Compensation and Ot

Stock Based Compensation and Other Benefit Plans - Summary of Stock Based Compensation Expense (Details) - 2017 Stock Plan $ in Thousands	6 Months Ended
	Jun. 30, 2019USD ($)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense related to stock-based compensation	$ 605
Weighted-average life over which expense is expected to be recognized (years)	3 years 7 months 13 days
Restricted Stock Unit Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 15
Unrecognized compensation expense related to stock-based compensation	$ 409
Weighted-average life over which expense is expected to be recognized (years)	4 years 9 months 25 days

Stock-Based Compensation and _7

Stock-Based Compensation and Other Benefit Plans - Summary of Activity for the Bank4Texas Warrants (Details) - Bank4Texas Warrants $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2019USD ($)$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants, Outstanding | shares	10,710,000
Warrants, Exercised | shares	(838,000)
Warrants, Outstanding | shares	9,872,000
Warrants, Vested and exercisable | shares	9,872,000
Weighted Average Exercise Price, Outstanding | $ / shares	$ 10.50
Weighted Average Exercise Price, Exercised | $ / shares	10.50
Weighted Average Exercise Price, Outstanding | $ / shares	10.50
Weighted Average Exercise Price, Vested and exercisable | $ / shares	$ 10.50
Aggregate Intrinsic Value, Exercised | $	$ 10
Aggregate Intrinsic Value, Outstanding | $	118
Vested and exercisable at June 30, 2019 | $	$ 118
Weighted Average Remaining Contractual Life (Years), Outstanding	1 year 4 months 24 days
Vested and exercisable at June 30, 2019	1 year 4 months 24 days

Basic and Diluted Earnings Pe_3

Basic and Diluted Earnings Per Common Share - Schedule of Computation of Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net income available to common stockholders	$ 5,827	$ 2,681	$ 9,637	$ 4,694
Weighted average number of common shares - basic	13,765,929	8,851,446	12,963,700	8,104,370
Effect of dilutive securities:
Employee stock-based compensation awards and warrants	470,315	454,583	469,060	341,590
Weighted average number of common shares - diluted	14,236,244	9,306,029	13,432,760	8,445,960
Basic earnings per common share	$ 0.42	$ 0.30	$ 0.74	$ 0.58
Diluted earnings per common share	$ 0.41	$ 0.29	$ 0.72	$ 0.56
Anti-dilutive warrants and stock options	9,350	70,266	1,850	70,266

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Effective tax rate	20.90%	20.40%	19.70%	20.10%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Unfunded Commitments | Commitments for Exposure to Credit Loss
Loss Contingencies [Line Items]
Reserve for unfunded commitments	$ 55	$ 48

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Unfunded Commitments (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Supply Commitment [Line Items]
Unfunded commitments, Total	$ 212,152	$ 176,703
Commercial and Standby Letters of Credit
Supply Commitment [Line Items]
Unfunded commitments, Total	1,088	547
Unfunded Loan Commitments
Supply Commitment [Line Items]
Unfunded commitments, Total	$ 211,064	$ 176,156

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Assets:
Total available for sale, Fair Value	$ 171,058	$ 179,461
U.S. Treasury Securities
Assets:
Total available for sale, Fair Value	32,536
U.S. Government Agencies
Assets:
Total available for sale, Fair Value	4,121	1,934
State and Municipal Obligations
Assets:
Total available for sale, Fair Value	25,418	18,048
Residential Mortgage-backed Securities
Assets:
Total available for sale, Fair Value	103,303	153,974
Corporate Bonds and Other Debt Securities
Assets:
Total available for sale, Fair Value	5,680	5,505
Level 1
Assets:
Total available for sale, Fair Value	32,536
Level 2
Assets:
Total available for sale, Fair Value	138,522	179,461
Fair Value Measurements on Recurring Basis
Assets:
Total available for sale, Fair Value	174,628	183,426
Fair Value Measurements on Recurring Basis | U.S. Treasury Securities
Assets:
Total available for sale, Fair Value	32,536
Fair Value Measurements on Recurring Basis | U.S. Government Agencies
Assets:
Total available for sale, Fair Value	4,121	1,934
Fair Value Measurements on Recurring Basis | State and Municipal Obligations
Assets:
Total available for sale, Fair Value	25,418	18,048
Fair Value Measurements on Recurring Basis | Residential Mortgage-backed Securities
Assets:
Total available for sale, Fair Value	103,303	153,974
Fair Value Measurements on Recurring Basis | Corporate Bonds and Other Debt Securities
Assets:
Total available for sale, Fair Value	5,680	5,505
Fair Value Measurements on Recurring Basis | SBA Servicing Rights
Assets:
Total available for sale, Fair Value	3,570	3,965
Fair Value Measurements on Recurring Basis | Level 1
Assets:
Total available for sale, Fair Value	32,536
Fair Value Measurements on Recurring Basis | Level 1 | U.S. Treasury Securities
Assets:
Total available for sale, Fair Value	32,536
Fair Value Measurements on Recurring Basis | Level 2
Assets:
Total available for sale, Fair Value	138,522	179,461
Fair Value Measurements on Recurring Basis | Level 2 | U.S. Government Agencies
Assets:
Total available for sale, Fair Value	4,121	1,934
Fair Value Measurements on Recurring Basis | Level 2 | State and Municipal Obligations
Assets:
Total available for sale, Fair Value	25,418	18,048
Fair Value Measurements on Recurring Basis | Level 2 | Residential Mortgage-backed Securities
Assets:
Total available for sale, Fair Value	103,303	153,974
Fair Value Measurements on Recurring Basis | Level 2 | Corporate Bonds and Other Debt Securities
Assets:
Total available for sale, Fair Value	5,680	5,505
Fair Value Measurements on Recurring Basis | Level 3
Assets:
Total available for sale, Fair Value	3,570	3,965
Fair Value Measurements on Recurring Basis | Level 3 | SBA Servicing Rights
Assets:
Total available for sale, Fair Value	$ 3,570	$ 3,965

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details)	3 Months Ended	6 Months Ended
	Jun. 30, 2019USD ($)	Jun. 30, 2019USD ($)
Fair Value Disclosures [Abstract]
Fair value, assets, level 1 to level 2 transfers	$ 0	$ 0
Fair value, assets, level 2 to level 1 transfers	0	0
Fair value, assets, transfers into level 3	0	0
Fair value, assets, transfers out of level 3	$ 0	$ 0

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Assets Measured at Fair Value on Non-Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Assets (classified in Level 3):
Other real estate owned and repossessed assets	$ 1,324	$ 782
Level 3 | Fair Value Measurements on Non-Recurring Basis
Assets (classified in Level 3):
Impaired loans	3,117	2,696
Other real estate owned and repossessed assets	$ 1,324	$ 782

Fair Value Measurements - Signi

Fair Value Measurements - Significant Unobservable Inputs Used in Recurring and Non-Recurring Fair Value Measurements (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other real estate owned	$ 1,324		$ 782
SBA servicing asset	3,570	$ 3,747	3,965	$ 3,521	$ 3,512	$ 3,411
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
SBA servicing asset	3,570		3,965
Level 3 | Fair Value Measurements on Non-Recurring Basis
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impaired loans	3,117		2,696
Other real estate owned	$ 1,324		$ 782
Level 3 | Fair Value Measurements on Non-Recurring Basis | Weighted Average | Collateral Discounts
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Range/Weighted Average	20.90%		19.20%
Level 3 | Fair Value Measurements on Non-Recurring Basis | Weighted Average | Collateral Discounts and Estimated Cost to Sell
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Range/Weighted Average	10.00%		10.00%
Level 3 | Fair Value Measurements on Non-Recurring Basis | Minimum | Collateral Discounts
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Range/Weighted Average	0.00%		0.00%
Level 3 | Fair Value Measurements on Non-Recurring Basis | Maximum | Collateral Discounts
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Range/Weighted Average	100.00%		100.00%
Level 3 | Fair Value Measurements on Non-Recurring Basis | Third Party Appraisals
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impaired loans	$ 3,117		$ 2,696
Other real estate owned	$ 1,324		$ 782
Level 3 | Fair Value Measurements on Recurring Basis | Weighted Average | Conditional Prepayment Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Range/Weighted Average	12.70%		11.80%
Level 3 | Fair Value Measurements on Recurring Basis | Weighted Average | Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Range/Weighted Average	11.50%		11.50%
Level 3 | Fair Value Measurements on Recurring Basis | Discounted Cash Flows
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
SBA servicing asset	$ 3,570		$ 3,965

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Financial Assets:
Total available for sale, Fair Value	$ 171,058		$ 179,461
SBA servicing rights	3,570	$ 3,747	3,965	$ 3,521	$ 3,512	$ 3,411
Level 1
Financial Assets:
Cash and cash equivalents	163,158		89,015
Time deposits in other banks	1,225
Total available for sale, Fair Value	32,536
Level 2
Financial Assets:
Total available for sale, Fair Value	138,522		179,461
FHLB and other bank stock	6,190		5,304
Loans held for sale	2,801		4,200
Accrued interest receivable	7,039		4,934
Bank-owned life insurance	15,432		7,401
Financial Liabilities:
Deposits	1,532,821		1,181,606
Accrued interest payable	1,134		702
Short-term borrowings			12,500
Long-term borrowings	77,543		66,735
Level 3
Financial Assets:
Loans, net	1,397,245		1,075,252
SBA servicing rights	3,570		3,965
Carrying Value
Financial Assets:
Cash and cash equivalents	163,158		89,015
Time deposits in other banks	1,225
Total available for sale, Fair Value	171,058		179,461
FHLB and other bank stock	6,190		5,304
Loans, net	1,403,061		1,086,654
Loans held for sale	2,583		3,945
Accrued interest receivable	7,039		4,934
Bank-owned life insurance	15,432		7,401
SBA servicing rights	3,570		3,965
Financial Liabilities:
Deposits	1,570,604		1,182,648
Accrued interest payable	1,134		702
Short-term borrowings			12,500
Long-term borrowings	80,525		67,916
Fair Value
Financial Assets:
Cash and cash equivalents	163,158		89,015
Time deposits in other banks	1,225
Total available for sale, Fair Value	171,058		179,461
FHLB and other bank stock	6,190		5,304
Loans, net	1,397,245		1,075,252
Loans held for sale	2,801		4,200
Accrued interest receivable	7,039		4,934
Bank-owned life insurance	15,432		7,401
SBA servicing rights	3,570		3,965
Financial Liabilities:
Deposits	1,532,821		1,181,606
Accrued interest payable	1,134		702
Short-term borrowings			12,500
Long-term borrowings	$ 77,543		$ 66,735

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Jul. 25, 2019	Jul. 24, 2019	May 04, 2018	Jun. 30, 2018	Jun. 30, 2018	Jul. 23, 2019	Jun. 30, 2019	Dec. 31, 2018
Subsequent Event [Line Items]
Common stock, par value							$ 0	$ 0
Shares issued in offering, net					$ 42,219
Common Stock
Subsequent Event [Line Items]
Number of shares issued and sold				2,300,000	2,300,000
Common Stock | Underwriters
Subsequent Event [Line Items]
Number of shares issued and sold			300,000
Subsequent Event
Subsequent Event [Line Items]
Shares issued in offering, net	$ 46,300
Subsequent Event | Common Stock
Subsequent Event [Line Items]
Number of shares issued and sold	2,300,000
Subsequent Event | Common Stock | Underwriters
Subsequent Event [Line Items]
Number of shares issued and sold	300,000
Subsequent Event | Line of Credit
Subsequent Event [Line Items]
Proceeds from offering, pay off a line of credit	$ 21,000
Subsequent Event | Underwriting Agreement
Subsequent Event [Line Items]
Business acquisition, shares issued	2,000,000
Common stock, par value	$ 0
Public offering price	$ 21.50
Common stock option to purchase additional shares by underwriters	300,000
Subsequent Event | First Beeville Financial Corporation
Subsequent Event [Line Items]
Business acquisition, cash paid		$ 19,200
Subsequent Event | First Beeville Financial Corporation | Common Stock
Subsequent Event [Line Items]
Business acquisition, shares issued		2,100,000
Subsequent Event | Texas corporation (“Spirit”) | Reorganization Agreement
Subsequent Event [Line Items]
Closing price						$ 22.10
Aggregate value of transaction						$ 65,600
Subsequent Event | Citizens
Subsequent Event [Line Items]
Business acquisition, cash paid	$ 19,200