Allegiance Bancshares (ABTX) 10-Q 8 May 18 2018 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 04, 2018
Document And Entity Information
Entity Registrant Name	Allegiance Bancshares, Inc.
Entity Central Index Key	1,642,081
Trading Symbol	abtx
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding (in shares)		13,325,736

CONSOLIDATED BALANCE SHEETS (Un

CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks	$ 143,176	$ 133,124
Interest-bearing deposits at other financial institutions	46,912	48,979
Total cash and cash equivalents	190,088	182,103
Available for sale securities, at fair value	307,411	309,615
Loans held for investment	2,290,494	2,270,876
Less: allowance for loan losses	(24,628)	(23,649)
Loans, net	2,265,866	2,247,227
Accrued interest receivable	10,521	12,194
Premises and equipment, net	18,605	18,477
Other real estate owned	365	365
Federal Home Loan Bank stock	14,128	12,862
Bank owned life insurance	22,563	22,422
Goodwill	39,389	39,389
Core deposit intangibles, net	3,079	3,274
Other assets	14,469	12,303
TOTAL ASSETS	2,886,484	2,860,231
Deposits:
Noninterest-bearing	694,880	683,110
Interest-bearing
Demand	143,178	215,499
Money market and savings	583,967	554,051
Certificates and other time	862,777	761,314
Total interest-bearing deposits	1,589,922	1,530,864
Total deposits	2,284,802	2,213,974
Accrued interest payable	1,212	610
Borrowed funds	232,569	282,569
Subordinated debt	48,719	48,659
Other liabilities	7,194	7,554
Total liabilities	2,574,496	2,553,366
COMMITMENTS AND CONTINGENCIES (See Note 11)
SHAREHOLDERS’ EQUITY:
Preferred stock, $1 par value; 1,000,000 shares authorized; no shares issued or outstanding	0	0
Common stock, $1 par value; 40,000,000 shares authorized; 13,302,462 shares issued and outstanding at March 31, 2018 and 13,226,826 shares issued and outstanding at December 31, 2017	13,302	13,227
Capital surplus	219,760	218,408
Retained earnings	82,533	74,894
Accumulated other comprehensive (loss) income	(3,607)	336
Total shareholders’ equity	311,988	306,865
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$ 2,886,484	$ 2,860,231

CONSOLIDATED BALANCE SHEETS (U3

CONSOLIDATED BALANCE SHEETS (Unaudited) (Parentheticals) - $ / shares	Mar. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Shares issued (in shares)	0	0
Shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	40,000,000	40,000,000
Common stock, shares issued (in shares)	13,302,462	13,226,826
Common stock, shares outstanding (in shares)	13,302,462	13,226,826

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
INTEREST INCOME:
Loans, including fees	$ 30,117	$ 25,260
Securities:
Taxable	599	498
Tax-exempt	1,459	1,624
Deposits in other financial institutions	216	130
Total interest income	32,391	27,512
INTEREST EXPENSE:
Demand, money market and savings deposits	976	654
Certificates and other time deposits	2,785	1,957
Borrowed funds	1,036	653
Subordinated debt	705	120
Total interest expense	5,502	3,384
NET INTEREST INCOME	26,889	24,128
Provision for loan losses	653	1,343
Net interest income after provision for loan losses	26,236	22,785
NONINTEREST INCOME:
Nonsufficient funds fees	176	199
Service charges on deposit accounts	223	195
Bank owned life insurance income	141	148
Rebate from correspondent bank	444	233
Other	662	566
Total noninterest income	1,646	1,341
NONINTEREST EXPENSE:
Salaries and employee benefits	12,794	10,562
Net occupancy and equipment	1,272	1,427
Depreciation	407	400
Data processing and software amortization	1,053	695
Professional fees	469	895
Regulatory assessments and FDIC insurance	534	589
Core deposit intangibles amortization	195	195
Communications	248	247
Advertising	330	263
Other	1,415	1,276
Total noninterest expense	18,717	16,549
INCOME BEFORE INCOME TAXES	9,165	7,577
Provision for income taxes	1,454	1,530
NET INCOME	$ 7,711	$ 6,047
EARNINGS PER SHARE:
Basic (in dollars per share)	$ 0.58	$ 0.46
Diluted (in dollars per share)	$ 0.57	$ 0.45

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 7,711	$ 6,047
Unrealized (loss) gain on securities:
Change in unrealized holding (loss) gain on available for sale securities during the period	(5,082)	1,197
Total other comprehensive (loss) income	(5,082)	1,197
Deferred tax benefit (expense) related to other comprehensive (loss) income	1,139	(419)
Other comprehensive (loss) income, net of tax	(3,943)	778
Comprehensive income	$ 3,768	$ 6,825

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS’ EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Capital Surplus	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Balance (in shares) at Dec. 31, 2016		12,958,341
Balance at Dec. 31, 2016	$ 279,817	$ 12,958	$ 212,649	$ 57,262	$ (3,052)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	6,047			6,047
Other comprehensive income (loss)	778				778
Common stock issued in connection with the exercise of stock options and restricted stock awards (in shares)		122,101
Common stock issued in connection with the exercise of stock options and restricted stock awards	2,147	$ 122	2,025
Repurchase of treasury stock	0					0
Stock based compensation expense	341		341
Balance (in shares) at Mar. 31, 2017		13,080,442
Balance at Mar. 31, 2017	289,130	$ 13,080	215,015	63,309	(2,274)	0
Balance (in shares) at Dec. 31, 2017		13,226,826
Balance at Dec. 31, 2017	306,865	$ 13,227	218,408	74,894	336	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	7,711			7,711
Other comprehensive income (loss)	(3,943)				(3,943)
Common stock issued in connection with the exercise of stock options and restricted stock awards (in shares)		75,636
Common stock issued in connection with the exercise of stock options and restricted stock awards	989	$ 75	914
Stock based compensation expense	438		438
Reclassification of amounts within AOCI to retained earnings due to tax reform (See Notes 1)	(72)			(72)
Balance (in shares) at Mar. 31, 2018		13,302,462
Balance at Mar. 31, 2018	$ 311,988	$ 13,302	$ 219,760	$ 82,533	$ (3,607)	$ 0

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 7,711	$ 6,047
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and core deposit intangibles amortization	602	595
Provision for loan losses	653	1,343
Excess tax benefit related to the exercise of stock options	(224)	(631)
Net amortization of premium on investments	832	826
Bank owned life insurance	(141)	(148)
Net accretion of discount on loans	(632)	(236)
Net amortization of discount on subordinated debentures	27	26
Net amortization of discount on certificates of deposit	(3)	(253)
Federal Home Loan Bank stock dividends	(67)	(46)
Stock based compensation expense	438	341
Decrease in accrued interest receivable and other assets	1,116	698
Increase in accrued interest payable and other liabilities	499	545
Net cash provided by operating activities	10,811	9,107
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from maturities and principal paydowns of available for sale securities	501,653	902,938
Purchase of available for sale securities	(505,363)	(903,331)
Net change in total loans	(18,660)	(93,996)
Purchase of bank premises and equipment	(1,076)	(557)
Net purchases of Federal Home Loan Bank stock	(1,199)	(6,642)
Net cash used in investing activities	(24,645)	(101,588)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in noninterest-bearing deposits	11,770	21,474
Net increase in interest-bearing deposits	59,061	120,908
Paydowns on borrowed funds	(50,000)	(10,000)
Proceeds from the issuance of common stock, stock option exercises, restricted stock awards and the ESPP	988	2,147
Net cash provided by financing activities	21,819	134,529
NET CHANGE IN CASH AND CASH EQUIVALENTS	7,985	42,048
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	182,103	142,098
CASH AND CASH EQUIVALENTS, END OF PERIOD	190,088	184,146
SUPPLEMENTAL INFORMATION:
Income taxes paid	1,900	0
Interest paid	$ 4,900	$ 3,421

NATURE OF OPERATIONS AND SUMMAR

NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING AND REPORTING POLICIES	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING AND REPORTING POLICIES	NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING AND REPORTING POLICIES Nature of Operations -Allegiance Bancshares, Inc. (“Allegiance”) and its wholly-owned subsidiary, Allegiance Bank, (the “Bank”, and together with Allegiance, collectively referred to as the “Company”) provide commercial and retail loans and commercial banking services. The Company derives substantially all of its revenues and income from the operation of the Bank. The Company is focused on delivering a wide variety of relationship-driven commercial banking products and community-oriented services tailored to meet the needs of small to medium-sized businesses, professionals and individuals through its 16 offices and one loan production office in Houston, Texas and the surrounding region. The Bank provides its customers with a variety of banking services including checking accounts, savings accounts and certificates of deposit, and its primary lending products are commercial, personal, automobile, mortgage and home improvement loans. The Bank also offers safe deposit boxes, automated teller machines, drive-through services and 24-hour depository facilities. Basis of Presentation -The accompanying unaudited condensed consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP") for interim financial information and in accordance with guidance provided by the Securities and Exchange Commission. Accordingly, the condensed consolidated financial statements do not include all of the information and footnotes required by GAAP for complete financial statements. The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates. In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all adjustments considered necessary for a fair presentation of the financial position, results of operations and cash flows of the Company on a consolidated basis, and all such adjustments are of a normal recurring nature. Transactions with Allegiance have been eliminated. The condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and footnotes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017 . Operating results for the three months ended March 31, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018 . Significant Accounting and Reporting Policies The Company’s significant accounting and reporting policies can be found in Note 1 of the Company’s annual financial statements included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017 . New Accounting Standards Adoption of New Accounting St andards ASU 2014-09 “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 supersedes the revenue recognition requirements in Revenue Recognition (Topic 605), and most industry-specific guidance throughout the Industry Topics of the Codification. The core principle of ASU 2014-09 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The Company records revenue from contracts with customers in accordance with Accounting Standards Codification Topic 606, “Revenue from Contracts with Customers” (“Topic 606”). Under Topic 606, the Company must identify the contract with a customer, identify the performance obligations in the contract, determine the transaction price, allocate the transaction price to the performance obligations in the contract, and recognize revenue when (or as) the Company satisfies a performance obligation. Significant revenue has not been recognized in the current reporting period that results from performance obligations satisfied in previous periods. The Company’s primary sources of revenue are derived from interest and dividends earned on loans, investment securities, and other financial instruments that are not within the scope of ASU 2014-09. The Company has evaluated the nature of its contracts with customers and determined that further disaggregation of revenue from contracts with customers into more granular categories beyond what is presented in the Consolidated Statements of Income was not necessary. The Company generally fully satisfies its performance obligations on its contracts with customers as services are rendered and the transaction prices are typically fixed, charged either on a periodic basis or based on activity. Because performance obligations are satisfied as services are rendered and the transaction prices are fixed, there is little judgment involved in applying Topic 606 that significantly affects the determination of the amount and timing of revenue from contracts with customers. The new standard was effective for the Company on January 1, 2018 and did not have a significant impact on its consolidated financial statements and related disclosures. ASU No. 2016-01, "Financial Instruments - Overall (Subtopic 825-10): Recognition of Financial Assets and Financial Liabilities." ASU 2016-01 makes targeted amendments to fair value measurement and disclosure guidance. ASU 2016-01 requires equity investments (other than equity method investments) to be measured at fair value with changes in fair value recognized in net income. This change is only applied if a readily determinable fair value can be obtained. The update also requires the use of exit prices to measure fair value for disclosure purposes as well as other enhanced disclosure requirements. ASU 2016-01 was effective for the Company on January 1, 2018 and did not have a significant impact on its financial statements and related disclosures. See Note 5 – Fair Value Disclosures for further information. ASU 2016-15, “Statement of Cash Flows (Topic 230) - Classification of Certain Cash Receipts and Cash Payments." ASU 2016-15 provides guidance related to certain cash flow issues in order to reduce the current and potential future diversity in practice. Among other things, the update clarifies the appropriate classification for proceeds from settlement of bank owned life insurance (BOLI) policies. Based on preliminary assessments, the Company expects to change the classification of proceeds from settlement of BOLI policies, if any, from operating activities to investing activities. ASU 2016-15 was effective for the Company on January 1, 2018 and did not have a significant impact on its financial statements and related disclosures. ASU 2018-02, “Income Statement - Reporting Comprehensive Income (Topic 220) - Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” ASU 2018-02 amends ASC 220, Income Statement - Reporting Comprehensive Income, to allow a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act. On December 22, 2017, the United States enacted tax reform legislation commonly known as the Tax Cuts and Jobs Act (the “Tax Act”), resulting in significant modifications to existing law. Authoritative guidance and interpretation by regulatory bodies is ongoing, and as such, the accounting for the effects of the Tax Act is not final and the full impact of the new regulation is still being evaluated. ASU 2018-02 is effective on January 1, 2019, with early adoption permitted. The Company early adopted and recognized a decrease to retained earnings of $72 thousand due to a reclassification on January 1, 2018. Newly Issued But Not Yet Effective Accounting Standards ASU 2016-02 “Leases (Topic 842)." 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, certain changes were made to align, where necessary, lessor accounting with the lessee accounting model and ASC Topic 606, “Revenue from Contracts with Customers.” ASU 2016-02 will be effective for the Company on January 1, 2019 and will require transition using a modified retrospective approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. Early application of this ASU is permitted for all entities. Adoption of ASU 2016-02 is not expected to have a material impact on the Company’s financial statements. The Company leases certain properties and equipment under operating leases that will result in the recognition of lease assets and lease liabilities on the Company’s balance sheet under the ASU. ASU 2016-13, “Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” Among other things, ASU 2016-13 requires the measurement of all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions and reasonable and supportable forecasts. Financial institutions and other organizations will now use forward-looking information to better form their credit loss estimates. Many of the loss estimation techniques applied today will still be permitted, although the inputs to those techniques will change to reflect the full amount of expected credit losses. In addition, ASU 2016-13 amends the accounting for credit losses on available for sale debt securities and purchased financial assets with credit deterioration. ASU 2016-13 is effective for the Company on January 1, 2020 and must be applied using the modified retrospective approach with limited exceptions. Early adoption is permitted for fiscal years, and interim periods within those years, beginning after December 15, 2018. While the Company is currently unable to reasonably estimate the impact of adopting ASU 2016-13, the Company expects that the impact of adoption will be significantly influenced by the composition, characteristics and quality of its loan and securities portfolios as well as the prevailing economic conditions and forecasts as of the adoption date. The Company has formed a cross functional team and with the assistance of a third-party provider is assessing the Company's data and system needs to evaluate the impact that adoption of this standard will have on the financial condition and results of operations of the Company. ASU No. 2017-04, “Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment,” ASU 2017-04 eliminates Step 2 from the goodwill impairment test which required entities to compute the implied fair value of goodwill. Under ASU 2017-04, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. ASU 2017-04 will be effective for the Company on January 1, 2020, with earlier adoption permitted and is not expected to have a significant impact on the Company's financial statements. ASU 2017-08,“Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20) - Premium Amortization on Purchased Callable Debt Securities.” ASU 2017-08 shortens the amortization period for certain callable debt securities held at a premium to require such premiums to be amortized to the earliest call date unless applicable guidance related to certain pools of securities is applied to consider estimated prepayments. Under prior guidance, entities were generally required to amortize premiums on individual, non-pooled callable debt securities as a yield adjustment over the contractual life of the security. ASU 2017-08 does not change the accounting for callable debt securities held at a discount. ASU 2017-08 will be effective for the Company on January 1, 2019, with early adoption permitted. The Company is currently evaluating the potential impact of ASU 2017-08 on its financial statements.

GOODWILL AND CORE DEPOSIT INTAN

GOODWILL AND CORE DEPOSIT INTANGIBLE ASSETS	3 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND CORE DEPOSIT INTANGIBLE ASSETS	GOODWILL AND CORE DEPOSIT INTANGIBLE ASSETS Changes in the carrying amount of the Company’s goodwill and core deposit intangible assets were as follows: Goodwill Core Deposit Intangibles (Dollars in thousands) Balance as of January 1, 2017 $ 39,389 $ 4,055 Amortization — (781 ) Balance as of December 31, 2017 39,389 3,274 Amortization — (195 ) Balance as of March 31, 2018 $ 39,389 $ 3,079 Goodwill is recorded on the acquisition date of an entity. Management performs an evaluation annually, and more frequently if a triggering event occurs, of whether any impairment of the goodwill and other intangible assets has occurred. If any such impairment is determined, a write-down is recorded. As of March 31, 2018 , there were no impairments recorded on goodwill and other intangible assets. The estimated aggregate future amortization expense for core deposit intangible assets remaining as of March 31, 2018 is as follows (dollars in thousands): Remaining 2018 $ 586 2019 781 2020 744 2021 484 2022 484 Thereafter — Total $ 3,079

SECURITIES

SECURITIES	3 Months Ended
	Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract]
SECURITIES	SECURITIES The amortized cost and fair value of investment securities were as follows: March 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (Dollars in thousands) Available for Sale U.S. Government and agency securities $ 8,299 $ 142 $ (59 ) $ 8,382 Municipal securities 221,403 1,166 (4,281 ) 218,288 Agency mortgage-backed pass-through securities 36,197 74 (954 ) 35,317 Corporate bonds and other 46,077 — (653 ) 45,424 Total $ 311,976 $ 1,382 $ (5,947 ) $ 307,411 December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (Dollars in thousands) Available for Sale U.S. Government and agency securities $ 8,507 $ 232 $ (24 ) $ 8,715 Municipal securities 222,330 2,470 (1,842 ) 222,958 Agency mortgage-backed pass-through securities 32,014 159 (361 ) 31,812 Corporate bonds and other 46,247 62 (179 ) 46,130 Total $ 309,098 $ 2,923 $ (2,406 ) $ 309,615 As of March 31, 2018 , the Company’s management does not expect to sell any securities classified as available for sale with material unrealized losses, and the Company believes it is more likely than not it will not be required to sell any of these securities before their anticipated recovery, at which time the Company will receive full value for the securities. The fair value is expected to recover as the securities approach their maturity date or repricing date or if market yields for such investments decline. Management does not believe any of the securities are impaired due to reasons of credit quality. Accordingly, as of March 31, 2018 , management believes the unrealized losses in the previous table are temporary and no other than temporary impairment loss has been realized in the Company’s consolidated statements of income. The amortized cost and fair value of investment securities at March 31, 2018 , by contractual maturity, are shown below. Expected maturities may differ from contractual maturities if borrowers have the right to call or prepay obligations at any time with or without call or prepayment penalties. Amortized Cost Fair Value (Dollars in thousands) Due in one year or less $ 11,873 $ 11,873 Due after one year through five years 71,990 71,051 Due after five years through ten years 92,765 91,478 Due after ten years 99,151 97,692 Subtotal 275,779 272,094 Agency mortgage-backed pass through securities 36,197 35,317 Total $ 311,976 $ 307,411 Securities with unrealized losses segregated by length of time such securities have been in a continuous loss position are as follows: March 31, 2018 Less than 12 Months More than 12 Months Total Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses (Dollars in thousands) Available for Sale U.S. Government and agency securities $ 3,342 $ (34 ) $ 531 $ (25 ) $ 3,873 $ (59 ) Municipal securities 100,904 (2,015 ) 55,389 (2,266 ) 156,293 (4,281 ) Agency mortgage-backed pass-through securities 20,426 (507 ) 8,461 (447 ) 28,887 (954 ) Corporate bonds and other 44,424 (653 ) — — 44,424 (653 ) Total $ 169,096 $ (3,209 ) $ 64,381 $ (2,738 ) $ 233,477 $ (5,947 ) December 31, 2017 Less than 12 Months More than 12 Months Total Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses (Dollars in thousands) Available for Sale U.S. Government and agency securities $ 3,110 $ (9 ) $ 595 $ (15 ) $ 3,705 $ (24 ) Municipal securities 42,249 (517 ) 56,483 (1,325 ) 98,732 (1,842 ) Agency mortgage-backed pass-through securities 13,238 (105 ) 8,921 (256 ) 22,159 (361 ) Corporate bonds and other 30,203 (179 ) — — 30,203 (179 ) Total $ 88,800 $ (810 ) $ 65,999 $ (1,596 ) $ 154,799 $ (2,406 ) No securities were sold during the three months ended March 31, 2018 and 2017. At March 31, 2018 and December 31, 2017 , the Company did not own securities of any one issuer, other than the U.S government and its agencies, in an amount greater than 10% of consolidated shareholders’ equity at such respective dates. The carrying value of pledged securities was $5.0 million at March 31, 2018 and $5.0 million at December 31, 2017 , respectively. The securities are pledged to further collateralize letters of credit issued by the Bank but confirmed by another financial institution.

LOANS AND ALLOWANCE FOR LOAN LO

LOANS AND ALLOWANCE FOR LOAN LOSSES	3 Months Ended
	Mar. 31, 2018
Loans and Allowance for Loan Losses [Abstract]
LOANS AND ALLOWANCE FOR LOAN LOSSES	LOANS AND ALLOWANCE FOR LOAN LOSSES The loan portfolio balances, net of unearned income and fees, consist of various types of loans primarily made to borrowers located within Texas and are classified by major type as follows: March 31, December 31, (Dollars in thousands) Commercial and industrial $ 447,168 $ 457,129 Mortgage warehouse 41,572 69,456 Real estate: Commercial real estate (including multi-family residential) 1,108,537 1,080,247 Commercial real estate construction and land development 257,566 243,389 1-4 family residential (including home equity) 317,842 301,219 Residential construction 108,882 109,116 Consumer and other 8,927 10,320 Total loans 2,290,494 2,270,876 Allowance for loan losses (24,628 ) (23,649 ) Loans, net $ 2,265,866 $ 2,247,227 Nonaccrual and Past Due Loans An aging analysis of the recorded investment in past due loans, segregated by class of loans, is as follows: March 31, 2018 Loans Past Due and Still Accruing 30-89 Days 90 or More Days Total Past Due Loans Nonaccrual Loans Current Loans Total Loans (Dollars in thousands) Commercial and industrial $ 1,545 $ — $ 1,545 $ 6,153 $ 439,470 $ 447,168 Mortgage warehouse — — — — 41,572 41,572 Real estate: Commercial real estate (including multi-family residential) 699 — 699 6,466 1,101,372 1,108,537 Commercial real estate construction and land development 75 — 75 — 257,491 257,566 1-4 family residential (including home equity) 1,164 — 1,164 754 315,924 317,842 Residential construction 1,787 — 1,787 — 107,095 108,882 Consumer and other 25 — 25 — 8,902 8,927 Total loans $ 5,295 $ — $ 5,295 $ 13,373 $ 2,271,826 $ 2,290,494 December 31, 2017 Loans Past Due and Still Accruing 30-89 Days 90 or More Days Total Past Due Loans Nonaccrual Loans Current Loans Total Loans (Dollars in thousands) Commercial and industrial $ 1,069 $ — $ 1,069 $ 6,437 $ 449,623 $ 457,129 Mortgage warehouse — — — — 69,456 69,456 Real estate: Commercial real estate (including multi-family residential) 4,932 — 4,932 6,110 1,069,205 1,080,247 Commercial real estate construction and land development 5,274 — 5,274 — 238,115 243,389 1-4 family residential (including home equity) 924 — 924 781 299,514 301,219 Residential construction 674 — 674 — 108,442 109,116 Consumer and other 74 — 74 — 10,246 10,320 Total loans $ 12,947 $ — $ 12,947 $ 13,328 $ 2,244,601 $ 2,270,876 Impaired Loans Impaired loans by class of loans are set forth in the following tables. March 31, 2018 Recorded Investment Unpaid Principal Balance Related Allowance (Dollars in thousands) With no related allowance recorded: Commercial and industrial $ 4,036 $ 4,519 $ — Mortgage warehouse — — — Real estate: Commercial real estate (including multi-family residential) 10,940 10,941 — Commercial real estate construction and land development 209 209 — 1-4 family residential (including home equity) 910 910 — Residential construction — — — Consumer and other — — — Total 16,095 16,579 — With an allowance recorded: Commercial and industrial 7,047 7,443 2,723 Mortgage warehouse — — — Real estate: Commercial real estate (including multi-family residential) 7,919 8,104 569 Commercial real estate construction and land development — — — 1-4 family residential (including home equity) — — — Residential construction — — — Consumer and other — — — Total 14,966 15,547 3,292 Total: Commercial and industrial 11,083 11,962 2,723 Mortgage warehouse — — — Real estate: Commercial real estate (including multi-family residential) 18,859 19,045 569 Commercial real estate construction and land development 209 209 — 1-4 family residential (including home equity) 910 910 — Residential construction — — — Consumer and other — — — $ 31,061 $ 32,126 $ 3,292 December 31, 2017 Recorded Investment Unpaid Principal Balance Related Allowance (Dollars in thousands) With no related allowance recorded: Commercial and industrial $ 5,792 $ 6,666 $ — Mortgage warehouse — — — Real estate: Commercial real estate (including multi-family residential) 12,155 12,155 — Commercial real estate construction and land development 209 209 — 1-4 family residential (including home equity) 948 948 — Residential construction — — — Consumer and other — — — Total 19,104 19,978 — With an allowance recorded: Commercial and industrial 5,600 5,652 1,640 Mortgage warehouse — — — Real estate: Commercial real estate (including multi-family residential) 8,009 8,194 716 Commercial real estate construction and land development — — — 1-4 family residential (including home equity) — — — Residential construction — — — Consumer and other — — — Total 13,609 13,846 2,356 Total: Commercial and industrial 11,392 12,318 1,640 Mortgage warehouse — — — Real estate: Commercial real estate (including multi-family residential) 20,164 20,349 716 Commercial real estate construction and land development 209 209 — 1-4 family residential (including home equity) 948 948 — Residential construction — — — Consumer and other — — — $ 32,713 $ 33,824 $ 2,356 The following table presents average impaired loans and interest recognized on impaired loans for the three months ended March 31, 2018 and 2017: Three Months Ended March 31, 2018 2017 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income (Dollars in thousands) Commercial and industrial $ 11,461 $ 94 $ 15,742 $ 139 Mortgage warehouse — — — — Real estate: Commercial real estate (including multi-family residential) 18,967 141 16,854 77 Commercial real estate construction and land development 209 3 72 — 1-4 family residential (including home equity) 927 4 575 1 Residential construction — — — — Consumer and other — — 14 — Total $ 31,564 $ 242 $ 33,257 $ 217 Credit Quality Indicators The Company categorizes loans into risk categories based on relevant information about the ability of borrowers to service their debt, including factors such as: current financial information, historical payment experience, credit documentation, public information and current economic trends. The Company analyzes loans individually by classifying the loans by credit risk. As part of the ongoing monitoring of the credit quality of the Company’s loan portfolio and methodology for calculating the allowance for credit losses, management assigns and tracks risk ratings to be used as credit quality indicators. The following is a general description of the risk ratings used: Pass —Loans classified as pass are loans with low to average risk and not otherwise classified as watch, special mention, substandard or doubtful. In addition, the guaranteed portion of SBA loans are considered pass risk rated loans. Watch —Loans classified as watch loans may still be of high quality, but have an element of risk added to the credit such as declining payment history, deteriorating financial position of the borrower or a decrease in collateral value. Special Mention —Loans classified as special mention have a potential weakness that deserves management’s close attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects for the loan or of the institution’s credit position at some future date. They are characterized by the distinct possibility that the institution will sustain some loss if the deficiencies are not corrected. Substandard —Loans classified as substandard have well-defined weaknesses on a continuing basis and are inadequately protected by the current net worth and paying capacity of the borrower, impaired or declining collateral values, or a continuing downturn in their industry which is reducing their profits to below zero and having a significantly negative impact on their cash flow. These classified loans are characterized by the distinct possibility that the institution will sustain some loss if the deficiencies are not corrected. Doubtful —Loans classified as doubtful have all the weaknesses inherent in those classified as substandard with the added characteristic that the weaknesses make collection or liquidation in full on the basis of currently existing facts, conditions and values highly questionable and improbable. Based on the most recent analysis performed, the risk category of loans by class of loan at March 31, 2018 is as follows: Pass Watch Special Mention Substandard Doubtful Total (Dollars in thousands) Commercial and industrial $ 419,105 $ 10,115 $ 1,610 $ 16,338 $ — $ 447,168 Mortgage warehouse 41,572 — — — — 41,572 Real estate: Commercial real estate (including multi-family residential) 1,045,532 24,830 3,067 35,108 — 1,108,537 Commercial real estate construction and land development 245,815 4,345 — 7,406 — 257,566 1-4 family residential (including home equity) 311,603 3,024 1,278 1,937 — 317,842 Residential construction 104,987 3,895 — — — 108,882 Consumer and other 8,851 75 — 1 — 8,927 Total loans $ 2,177,465 $ 46,284 $ 5,955 $ 60,790 $ — $ 2,290,494 The following table presents the risk category of loans by class of loan at December 31, 2017 : Pass Watch Special Mention Substandard Doubtful Total (Dollars in thousands) Commercial and industrial $ 427,336 $ 10,274 $ 2,195 $ 17,324 $ — $ 457,129 Mortgage warehouse 69,456 — — — — 69,456 Real estate: Commercial real estate (including multi-family residential) 1,016,831 23,039 4,685 35,692 — 1,080,247 Commercial real estate construction and land development 231,536 4,397 — 7,456 — 243,389 1-4 family residential (including home equity) 295,744 2,696 785 1,994 — 301,219 Residential construction 103,611 5,505 — — — 109,116 Consumer and other 10,207 111 — 2 — 10,320 Total loans $ 2,154,721 $ 46,022 $ 7,665 $ 62,468 $ — $ 2,270,876 Allowance for Loan Losses The following table presents the activity in the allowance for loan losses by portfolio type for the three months ended March 31, 2018 and 2017 : Commercial and industrial Mortgage warehouse Commercial real estate (including multi-family residential) Commercial real estate construction and land development 1-4 family residential (including home equity) Residential construction Consumer and other Total (Dollars in thousands) Allowance for loan losses: Three Months Ended Balance December 31, 2017 $ 7,694 $ — $ 10,253 $ 2,525 $ 2,140 $ 942 $ 95 $ 23,649 Provision for loan losses 1,440 — (963 ) 20 160 4 (8 ) 653 Charge-offs (367 ) — (40 ) — — — — (407 ) Recoveries 631 — 102 — — — — 733 Net recoveries 264 — 62 — — — — 326 Balance March 31, 2018 $ 9,398 $ — $ 9,352 $ 2,545 $ 2,300 $ 946 $ 87 $ 24,628 Allowance for loan losses: Three Months Ended Balance December 31, 2016 $ 5,059 $ — $ 8,950 $ 1,217 $ 1,876 $ 748 $ 61 $ 17,911 Provision for loan losses 806 — 208 391 (40 ) (11 ) (11 ) 1,343 Charge-offs (627 ) — — — — — — (627 ) Recoveries 46 — — — 10 — 4 60 Net charge-offs (581 ) — — — 10 — 4 (567 ) Balance March 31, 2017 $ 5,284 $ — $ 9,158 $ 1,608 $ 1,846 $ 737 $ 54 $ 18,687 The following table presents the balance of the allowance for loan losses by portfolio type based on the impairment method as of March 31, 2018 and December 31, 2017 : Commercial and industrial Mortgage warehouse Commercial real estate (including multi-family residential) Commercial real estate construction and land development 1-4 family residential (including home equity) Residential construction Consumer and other Total (Dollars in thousands) Allowance for loan losses related to: March 31, 2018 Individually evaluated for impairment $ 2,723 $ — $ 569 $ — $ — $ — $ — $ 3,292 Collectively evaluated for impairment 6,675 — 8,783 2,545 2,300 946 87 21,336 Total allowance for loan losses $ 9,398 $ — $ 9,352 $ 2,545 $ 2,300 $ 946 $ 87 $ 24,628 December 31, 2017 Individually evaluated for impairment $ 1,640 $ — $ 716 $ — $ — $ — $ — $ 2,356 Collectively evaluated for impairment 6,054 — 9,537 2,525 2,140 942 95 21,293 Total allowance for loan losses $ 7,694 $ — $ 10,253 $ 2,525 $ 2,140 $ 942 $ 95 $ 23,649 The following table presents the recorded investment in loans held for investment by portfolio type based on the impairment method as of March 31, 2018 and December 31, 2017 : Commercial and industrial Mortgage warehouse Commercial real estate (including multi-family residential) Commercial real estate construction and land development 1-4 family residential (including home equity) Residential construction Consumer and other Total (Dollars in thousands) Recorded investment in loans: March 31, 2018 Individually evaluated for impairment $ 11,083 $ — $ 18,859 $ 209 $ 910 $ — $ — $ 31,061 Collectively evaluated for impairment 436,085 41,572 1,089,678 257,357 316,932 108,882 8,927 2,259,433 Total loans evaluated for impairment $ 447,168 $ 41,572 $ 1,108,537 $ 257,566 $ 317,842 $ 108,882 $ 8,927 $ 2,290,494 December 31, 2017 Individually evaluated for impairment $ 11,392 $ — $ 20,164 $ 209 $ 948 $ — $ — $ 32,713 Collectively evaluated for impairment 445,737 69,456 1,060,083 243,180 300,271 109,116 10,320 2,238,163 Total loans evaluated for impairment $ 457,129 $ 69,456 $ 1,080,247 $ 243,389 $ 301,219 $ 109,116 $ 10,320 $ 2,270,876 Troubled Debt Restructurings As of March 31, 2018 and December 31, 2017 , the Company had a recorded investment in troubled debt restructurings of $25.4 million and $25.6 million , respectively. The Company allocated $1.9 million and $2.2 million of specific reserves for troubled debt restructurings at March 31, 2018 and December 31, 2017 , respectively, and did not commit to lend additional amounts on these loans. The following tables present information regarding loans modified in a troubled debt restructuring during the three months ended March 31, 2018 and 2017: As of March 31, 2018 2017 Number of Contracts Pre-modification of Outstanding Recorded Investment Post-modification of Outstanding Recorded Investment Number of Contracts Pre-modification of Outstanding Recorded Investment Post-modification of Outstanding Recorded Investment (Dollars in thousands) Troubled Debt Restructurings Commercial and industrial 6 337 337 1 316 316 Mortgage warehouse — — — — — — Real estate: Commercial real estate (including multi-family residential) — — — 1 1,328 1,328 Commercial real estate construction and land development — — — — — — 1-4 family residential (including home equity) — — — 1 86 86 Residential construction — — — — — — Consumer and other — — — — — — Total 6 337 337 3 1,730 1,730 Troubled debt restructurings resulted in charge-offs of $17 thousand and $395 thousand during the three months ended March 31, 2018 and 2017, respectively. As of March 31, 2018 , there have been no defaults on any loans that were modified as troubled debt restructurings during the preceding 12 months. Default is determined at 90 or more days past due. The modifications primarily related to extending the amortization periods of the loans. The Company did not grant principal reductions on any restructured loans. There were no commitments to lend additional amounts for the three months ended March 31, 2018 and 2017. During the three months ended March 31, 2018 , the Company added $337 thousand in new troubled debt restructurings, of which $314 thousand were still outstanding on March 31, 2018 .

FAIR VALUE

FAIR VALUE	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
FAIR VALUE	FAIR VALUE The Company uses fair value measurements to record fair value adjustments to certain assets and to determine fair value disclosures. Fair value represents the exchange price that would be received from selling an asset or paid to transfer a liability, otherwise known as an “exit price,” in the principal or most advantageous market available to the entity in an orderly transaction between market participants on the measurement date. Fair Value Hierarchy Fair value is the exchange price that would be received for an asset or paid to transfer a liability (exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Company groups financial assets and financial liabilities measured at fair value in three levels, based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. These levels are: • Level 1—Quoted prices for identical assets or liabilities in active markets that the entity has the ability to access as of the measurement date. • Level 2—Significant other observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data. • Level 3—Significant unobservable inputs that reflect management’s judgment and assumptions that market participants would use in pricing an asset or liability that are supported by little or no market activity. The carrying amounts and estimated fair values of financial instruments that are reported on the balance sheet are as follows: As of March 31, 2018 Carrying Estimated Fair Value Amount Level 1 Level 2 Level 3 Total (Dollars in thousands) Financial assets Cash and cash equivalents $ 190,088 $ 190,088 $ — $ — $ 190,088 Available for sale securities 307,411 — 307,411 — 307,411 Loans held for investment, net of allowance 2,265,866 — — 2,257,861 2,257,861 FHLB stock 14,128 N/A N/A N/A N/A Accrued interest receivable 10,521 2 2,060 8,459 10,521 Financial liabilities Deposits $ 2,284,802 $ — $ 2,276,516 $ — $ 2,276,516 Accrued interest payable 1,212 — 1,212 — 1,212 Borrowed funds 232,569 — 237,498 — 237,498 Subordinated debt and subordinated debentures 48,719 — 48,719 — 48,719 As of December 31, 2017 Carrying Estimated Fair Value Amount Level 1 Level 2 Level 3 Total (Dollars in thousands) Financial assets Cash and cash equivalents $ 182,103 $ 182,103 $ — $ — $ 182,103 Available for sale securities 309,615 — 309,615 — 309,615 Loans held for investment, net of allowance 2,247,227 — — 2,238,721 2,238,721 FHLB stock 12,862 N/A N/A N/A N/A Accrued interest receivable 12,194 3 3,296 8,895 12,194 Financial liabilities Deposits $ 2,213,974 $ — $ 2,209,111 $ — $ 2,209,111 Accrued interest payable 610 — 610 — 610 Borrowed funds 282,569 — 288,887 — 288,887 Subordinated debt and subordinated debentures 48,659 — 48,659 — 48,659 The following tables present fair values for assets measured at fair value on a recurring basis: As of March 31, 2018 Level 1 Level 2 Level 3 Total (Dollars in thousands) Available for sale securities: U.S. Government and agency securities $ — $ 8,382 $ — $ 8,382 Municipal securities — 218,288 — 218,288 Agency mortgage-backed pass-through securities — 35,317 — 35,317 Corporate bonds and other — 45,424 — 45,424 Total $ — $ 307,411 $ — $ 307,411 As of December 31, 2017 Level 1 Level 2 Level 3 Total (Dollars in thousands) Available for sale securities: U.S. Government and agency securities $ — $ 8,715 $ — $ 8,715 Municipal securities — 222,958 — 222,958 Agency mortgage-backed pass-through securities — 31,812 — 31,812 Corporate bonds and other — 46,130 — 46,130 Total $ — $ 309,615 $ — $ 309,615 There were no liabilities measured at fair value on a recurring basis as of March 31, 2018 or December 31, 2017 . There were no transfers between levels during the three months ended March 31, 2018 or 2017 . Certain assets and liabilities are measured at fair value on a nonrecurring basis; that is, the instruments are not measured at fair value on an ongoing basis, but are subject to fair value adjustments in certain circumstances such as evidence of impairment. As of March 31, 2018 Level 1 Level 2 Level 3 (Dollars in thousands) Impaired loans: Commercial and industrial $ — $ — $ 4,720 Commercial real estate (including multi-family residential) — — 7,535 Other real estate owned — — 365 $ — $ — $ 12,620 As of December 31, 2017 Level 1 Level 2 Level 3 (Dollars in thousands) Impaired loans: Commercial and industrial $ — $ — $ 4,012 Commercial real estate (including multi-family residential) — — 7,478 Other real estate owned — — 365 $ — $ — $ 11,855 Impaired Loans with Specific Allocation of Allowance During the three months ended March 31, 2018 and the year ended December 31, 2017, certain impaired loans were reevaluated and reported at fair value through a specific allocation of the allowance for loan losses. At March 31, 2018 , the total reported fair value of impaired loans of $12.3 million based on collateral valuations utilizing Level 3 valuation inputs had a carrying value of $15.5 million that was reduced by specific allowance allocations totaling $3.3 million . At December 31, 2017, the total reported fair value of impaired loans of $11.5 million based on collateral valuations utilizing Level 3 valuation inputs had a carrying value of $13.8 million that was reduced by specific allowance allocations totaling $2.4 million . Other Real Estate Owned At March 31, 2018 and December 31, 2017, the balance of other real estate owned consisted of a $365 thousand foreclosed commercial real estate property recorded as a result of obtaining physical possession of the property. At March 31, 2018 , there was no formal foreclosure in process on this other real estate owned.

DEPOSITS

DEPOSITS	3 Months Ended
	Mar. 31, 2018
Deposit Liabilities [Abstract]
DEPOSITS	DEPOSITS Time deposits that meet or exceed the Federal Deposit Insurance Corporation Insurance limit of $250 thousand at March 31, 2018 and December 31, 2017 were $260.6 million and $227.4 million , respectively. Scheduled maturities of time deposits for the next five years are as follows (dollars in thousands): Within one year $ 575,405 After one but within two years 112,102 After two but within three years 38,811 After three but within four years 36,764 After four but within five years 99,695 Total $ 862,777 The Company has $243.2 million and $314.8 million of brokered deposits as of March 31, 2018 and December 31, 2017 , respectively; and there are no major concentrations of deposits with any one depositor at March 31, 2018 and December 31, 2017 . Included in these amounts are reciprocal deposits that the Company has placed through the Certificates of Deposits Account Registry Service (CDARS) Network of $73.1 million and $68.4 million , at March 31, 2018 and December 31, 2017 , respectively.

BORROWINGS AND BORROWING CAPACI

BORROWINGS AND BORROWING CAPACITY	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
BORROWINGS AND BORROWING CAPACITY	BORROWINGS AND BORROWING CAPACITY The Company has an available line of credit with the Federal Home Loan Bank (“FHLB”) of Dallas, which allows the Company to borrow on a collateralized basis. FHLB advances are used to manage liquidity as needed. The advances are secured by a blanket lien on certain loans. Maturing advances are replaced by drawing on available cash, making additional borrowings or through increased customer deposits. At March 31, 2018, the Company had a total borrowing capacity of $1.00 billion , of which $702.4 million was available and $298.9 million was outstanding. FHLB advances of $232.0 million were outstanding at March 31, 2018 , at a weighted average interest rate of 1.91% . Letters of credit were $66.9 million at March 31, 2018 , of which $7.1 million will expire in July 2018, $15.1 million will expire in August 2018, $7.0 million will expire in September 2018, $25.0 million will expire in October 2018, $6.1 million will expire in December 2018, $1.7 million will expire in January 2019, $3.1 million will expire in February 2019, $300 thousand will expire in December 2019 and $1.5 million will expire in January 2020. In 2015, the Company borrowed an additional $ 18.0 million under its credit agreement with another financial institution, which was in addition to the $10.1 million of indebtedness incurred under the same credit agreement in 2014. The credit agreement matures in December 2021. The Company used the funds borrowed in 2015 to repay debt that F&M Bancshares, Inc. owed and used the funds borrowed in 2014 to pay off a previous borrowing with another financial institution that had been entered into during 2013 in conjunction with the acquisition of Independence Bank. In October 2015, the Company paid down $ 27.5 million of the credit agreement with a portion of the proceeds from the initial public offering of Allegiance common stock. The credit agreement includes certain restrictive covenants. At March 31, 2018, the Company believes it is in compliance with its debt covenants and had not been made aware of any noncompliance by the lender. The interest rate on the outstanding debt under the revolving credit agreement is the Prime rate minus 25 basis points, or 4.25% , at March 31, 2018 , and is paid quarterly. Scheduled principal maturities are as follows (dollars in thousands): Remaining 2018 $ — 2019 — 2020 — 2021 569 Total $ 569

SUBORDINATED DEBT

SUBORDINATED DEBT	3 Months Ended
	Mar. 31, 2018
Subordinated Borrowings [Abstract]
SUBORDINATED DEBT	SUBORDINATED DEBT Junior Subordinated Debentures On January 1, 2015, the Company acquired F&M Bancshares and assumed Farmers & Merchants Capital Trust II and Farmers & Merchants Capital Trust III. Each of these trusts is a capital or statutory business trust organized for the sole purpose of issuing trust securities and investing the proceeds in the Company’s junior subordinated debentures. The preferred trust securities of each trust represent preferred beneficial interests in the assets of the respective trusts and are subject to mandatory redemption upon payment of the junior subordinated debentures held by the trust. The common securities of each trust are wholly owned by the Company. Each trust’s ability to pay amounts due on the trust preferred securities is solely dependent upon the Company making payment on the related junior subordinated debentures. The debentures, which are the only assets of each trust, are subordinate and junior in right of payment to all of the Company’s present and future senior indebtedness. The Company has fully and unconditionally guaranteed each trust’s obligations under the trust securities issued by such trust to the extent not paid or made by such trust, provided such trust has funds available for such obligations. Under the provisions of each issue of the debentures, the Company has the right to defer payment of interest on the debentures at any time, or from time to time, for periods not exceeding five years. If interest payments on either issue of the debentures are deferred, the distributions on the applicable trust preferred securities and common securities will also be deferred. The Company assumed the junior subordinated debentures with an aggregate original principal amount of $11.3 million and a carrying fair value at March 31, 2018 of $9.3 million . At acquisition, the Company recorded a discount of $2.5 million on the debentures. The difference between the carrying value and contractual balance will be recognized as a yield adjustment over the remaining term for the debentures. At March 31, 2018 , the Company had $11.3 million outstanding in junior subordinated debentures issued to the Company’s unconsolidated subsidiary trusts. The junior subordinated debentures are included in Tier 1 capital under current regulatory guidelines and interpretations. A summary of pertinent information related to the Company’s issues of junior subordinated debentures outstanding at March 31, 2018 is set forth in the table below: Description Issuance Date Trust Preferred Securities Outstanding Interest Rate (1) Junior Subordinated Debt Owed to Trusts Maturity Date (2) (Dollars in thousands) Farmers & Merchants Capital Trust II November 13, 2003 $ 7,500 3 month LIBOR + 3.00% $ 7,732 November 8, 2033 Farmers & Merchants Capital Trust III June 30, 2005 3,500 3 month LIBOR + 1.80% 3,609 July 7, 2035 (1) The 3-month LIBOR in effect as of March 31, 2018 was 2.1796% . (2) All debentures are currently callable. Subordinated Notes In December 2017, the Bank completed the issuance, through a private placement, of $40.0 million aggregate principal amount of Fixed-to-Floating Rate Subordinated Notes (the "Notes") due December 15, 2027. The Notes were issued at a price equal to 100% of the principal amount, resulting in net proceeds to the Bank of $39.4 million . The Bank intends to use the net proceeds from the offering to support its growth and for general corporate purposes. The Notes are intended to qualify as Tier 2 capital for bank regulatory purposes. The Notes bear a fixed interest rate of 5.25% per annum until (but excluding) December 15, 2022, payable semi-annually in arrears. From December 15, 2022, the Notes will bear a floating rate of interest equal to 3-Month LIBOR + 3.03% until the Notes mature on December 15, 2027, or such earlier redemption date, payable quarterly in arrears. The Notes will be redeemable by the Bank, in whole or in part, on or after December 15, 2022 or, in whole but not in part, upon the occurrence of certain specified tax events, capital events or investment company events. Any redemption will be at a redemption price equal to 100% of the principal amount of Notes being redeemed, plus accrued and unpaid interest, and will be subject to, and require, prior regulatory approval. The Notes are not subject to redemption at the option of the holders.

INCOME TAXES

INCOME TAXES	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The amount of the Company’s federal and state income tax expense is influenced by the amount of pre-tax income, the amount of tax-exempt income and the amount of other nondeductible items. For the three months ended March 31, 2018 and 2017, income tax expense was $1.5 million , for both periods. The effective income tax rate for the three months ended March 31, 2018 and 2017 was 15.9% and 20.2% , respectively. The decrease in income tax expense and the effective tax rate year over year was primarily attributable to the Tax Act enacted on December 22, 2017, which reduced the U.S. federal statutory income tax rate from 35% to 21% effective January 1, 2018. Interest and penalties related to tax positions are recognized in the period in which they begin accruing or when the entity claims the position that does not meet the minimum statutory thresholds. The Company does not have any uncertain tax positions and does not have any interest and penalties recorded in the income statement for the three months ended March 31, 2018 and 2017. The Company is no longer subject to examination by the U.S. Federal Tax Jurisdiction for the years prior to 2014.

STOCK BASED COMPENSATION

STOCK BASED COMPENSATION	3 Months Ended
	Mar. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
STOCK BASED COMPENSATION	STOCK BASED COMPENSATION During 2015, the Company’s Board of Directors and shareholders approved the 2015 Amended and Restated Stock Awards and Incentive Plan (the “Plan”) covering certain awards of stock-based compensation to key employees and directors of the Company. The Plan was amended in 2017 as the shareholders authorized a maximum aggregate number of shares of stock to be issued of 1,900,000 , any or all of which may be issued through incentive stock options. The Company accounts for stock based employee compensation plans using the fair value-based method of accounting. The Company recognized total stock based compensation expense of $438 thousand and $341 thousand for the three months ended March 31, 2018 and 2017, respectively. Stock Options Options to purchase a total of 1,309,231 shares of Company stock have been granted as of March 31, 2018 . Under the Plan, options are exercisable up to 10 years from the date of the grant and are fully vested 4 years after the date of grant. The fair value of stock options granted is estimated at the date of grant using the Black-Scholes option-pricing model. A summary of the activity in the stock option plan during the three months ended March 31, 2018 is set forth below: Number of Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (In thousands) (In years) (In thousands) Options outstanding, January 1, 2018 775 $ 19.94 5.72 $ 13,718 Options granted 4 40.40 Options exercised (74 ) 12.94 Options forfeited (9 ) 29.10 Options outstanding, March 31, 2018 696 $ 20.72 5.82 $ 12,850 Options vested and exercisable, March 31, 2018 475 $ 18.00 4.83 $ 10,043 Restricted Stock Awards During the three months ended March 31, 2018 , the Company issued 300 shares of restricted stock. The forfeiture restrictions on restricted stock shares generally lapse over a period of 4 years, and the shares are considered outstanding at the date of issuance. The Company accounts for restricted stock grants by recording the fair value of the grant on the award date as compensation expense over the vesting period. A summary of the activity of the nonvested shares of restricted stock during the three months ended March 31, 2018 is as follows: Number of Shares Weighted Average Grant Date Fair Value (Shares in thousands) Nonvested share awards outstanding, January 1, 2018 41 $ 30.46 Share awards granted — 40.40 Share awards vested (10 ) 23.66 Unvested share awards forfeited — — Nonvested share awards outstanding, March 31, 2018 31 $ 31.49

OFF-BALANCE SHEET ARRANGEMENTS,

OFF-BALANCE SHEET ARRANGEMENTS, COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
OFF-BALANCE SHEET ARRANGEMENTS, COMMITMENTS AND CONTINGENCIES	OFF-BALANCE SHEET ARRANGEMENTS, COMMITMENTS AND CONTINGENCIES In the normal course of business, the Company enters into various transactions, which, in accordance with accounting principles generally accepted in the United States, are not included in the Company’s consolidated balance sheets. The Company enters into these transactions to meet the financing needs of its customers. These transactions include commitments to extend credit and standby letters of credit, which involve to varying degrees elements of credit risk and interest rate risk in excess of the amounts recognized in the consolidated balance sheets. The Company uses the same credit policies in making commitments and conditional obligations as it does for on balance sheet instruments. The contractual amounts of financial instruments with off-balance sheet risk are as follows: March 31, 2018 December 31, 2017 Fixed Rate Variable Rate Fixed Rate Variable Rate (Dollars in thousands) Commitments to extend credit $ 254,424 $ 342,980 $ 369,573 $ 250,467 Standby letters of credit 15,212 1,725 15,445 1,725 Total $ 269,636 $ 344,705 $ 385,018 $ 252,192 Commitments to make loans are generally made for an approval period of 120 days or fewer. As of March 31, 2018 , the funded fixed rate loan commitments had interest rates ranging from 1.75% to 7.50% with a weighted average maturity and rate of 2.16 years and 5.01% , respectively. Litigation From time to time, the Company is subject to claims and litigation arising in the ordinary course of business. In the opinion of management, the Company is not party to any legal proceedings the resolution of which it believes would have a material adverse effect on the Company’s business, prospects, financial condition, liquidity, results of operation, cash flows or capital levels. However, one or more unfavorable outcomes in any claim or litigation against the Company could have a material adverse effect for the period in which such claim or litigation is resolved. In addition, regardless of their merits or their ultimate outcomes, such matters are costly, divert management’s attention and may materially adversely affect the Company’s reputation, even if resolved in its favor. The Company intends to defend itself vigorously against any future claims or litigation.

REGULATORY CAPITAL MATTERS

REGULATORY CAPITAL MATTERS	3 Months Ended
	Mar. 31, 2018
Banking and Thrift [Abstract]
REGULATORY CAPITAL MATTERS	REGULATORY CAPITAL MATTERS The Company and the Bank are subject to various regulatory capital requirements administered by the federal banking agencies. Capital adequacy guidelines, and for banks, prompt corrective action regulations, involve quantitative measures of assets, liabilities and certain off balance sheet items calculated under regulatory accounting practices. Capital amounts and classifications are also subject to qualitative judgments by regulators about components, risk weightings and other factors. Failure to meet minimum capital requirements can cause regulators to initiate actions that, if undertaken, could have a direct material effect on the Company’s consolidated financial statements. The final rules implementing Basel Committee on Banking Supervision's capital guideline for U.S. Banks (Basel III Rules) became effective for the Company on January 1, 2015 with full compliance with all of the requirements being phased in over a multi-year schedule, and fully phased in by January 1, 2019. Starting in January 2016, the implementation of the capital conservation buffer was effective for the Company starting at the 0.625% level and increasing 0.625% each year thereafter, until it reaches 2.5% on January 1, 2019. Management believes as of March 31, 2018 and December 31, 2017 the Company and the Bank met all capital adequacy requirements to which they were then subject. Prompt corrective action regulations provide five classifications: well capitalized, adequately capitalized, undercapitalized, significantly undercapitalized, and critically undercapitalized, although these terms are not used to represent overall financial condition. If adequately capitalized, regulatory approval is required to accept brokered deposits. If undercapitalized, capital distributions are limited, as is asset growth and expansion, and capital restoration plans are required. The following is a summary of the Company’s and the Bank’s actual and required capital ratios at March 31, 2018 and December 31, 2017 : Actual Minimum Required For Capital Adequacy Purposes Minimum Required Plus Capital To Be Categorized As Well Capitalized Under Prompt Corrective Action Provisions Amount Ratio Amount Ratio Amount Ratio Amount Ratio (Dollars in thousands) ALLEGIANCE BANCSHARES, INC. (Consolidated) As of March 31, 2018 Total Capital (to risk weighted assets) $ 346,474 13.72 % $ 201,989 8.00 % $ 249,330 9.875 % N/A N/A Common Equity Tier 1 Capital (to risk weighted assets) 273,127 10.82 % 113,619 4.50 % 160,960 6.375 % N/A N/A Tier I Capital (to risk weighted assets) 282,458 11.19 % 151,492 6.00 % 198,833 7.875 % N/A N/A Tier I Capital (to average tangible assets) 282,458 9.98 % 113,180 4.00 % 113,180 4.000 % N/A N/A As of December 31, 2017 Total Capital (to risk weighted assets) $ 336,829 13.43 % $ 200,687 8.00 % $ 232,044 9.250 % N/A N/A Common Equity Tier 1 Capital (to risk weighted assets) 264,521 10.54 % 112,886 4.50 % 144,244 5.750 % N/A N/A Tier I Capital (to risk weighted assets) 273,825 10.92 % 150,515 6.00 % 181,872 7.250 % N/A N/A Tier I Capital (to average tangible assets) 273,825 9.84 % 111,274 4.00 % 96,708 4.000 % N/A N/A ALLEGIANCE BANK As of March 31, 2018 Total Capital (to risk weighted assets) $ 340,358 13.49 % $ 201,890 8.00 % $ 249,208 9.875 % $ 252,362 10.00 % Common Equity Tier 1 Capital (to risk weighted assets) 276,342 10.95 % 113,563 4.50 % 160,881 6.375 % 164,035 6.50 % Tier I Capital (to risk weighted assets) 276,342 10.95 % 151,417 6.00 % 198,735 7.875 % 201,890 8.00 % Tier I Capital (to average tangible assets) 276,342 9.77 % 113,132 4.00 % 113,132 4.000 % 141,415 5.00 % As of December 31, 2017 Total Capital (to risk weighted assets) $ 331,872 13.24 % $ 200,596 8.00 % $ 231,939 9.250 % $ 250,745 10.00 % Common Equity Tier 1 Capital (to risk weighted assets) 268,868 10.72 % 112,835 4.50 % 144,179 5.750 % 162,985 6.50 % Tier I Capital (to risk weighted assets) 268,868 10.72 % 150,447 6.00 % 181,790 7.250 % 200,596 8.00 % Tier I Capital (to average tangible assets) 268,868 9.67 % 111,230 4.00 % 111,230 4.000 % 139,037 5.00 %

EARNINGS PER COMMON SHARE

EARNINGS PER COMMON SHARE	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
EARNINGS PER COMMON SHARE	EARNINGS PER COMMON SHARE Diluted earnings per common share is computed using the weighted-average number of common shares determined for the basic earnings per common share computation plus the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock using the treasury stock method. Outstanding stock options issued by the Company represent the only dilutive effect reflected in diluted weighted average shares. Restricted shares are considered outstanding at the date of grant, accounted for as participating securities and included in basic and diluted weighted average common shares outstanding. Three Months Ended March 31, 2018 2017 Amount Per Share Amount Amount Per Share Amount (Amounts in thousands, except per share data) Net income attributable to common shareholders $ 7,711 $ 6,047 Basic: Weighted average common shares outstanding 13,262 $ 0.58 13,021 $ 0.46 Diluted: Add incremental shares for: Dilutive effect of stock option exercises 280 356 Total 13,542 $ 0.57 13,377 $ 0.45 Stock options for 19 thousand shares were not considered in computing diluted earnings per common share as of March 31, 2018 because they were antidilutive. There were no antidilutive shares as of March 31, 2017.

SUBSEQUENT EVENT

SUBSEQUENT EVENT	3 Months Ended
	Mar. 31, 2018
Subsequent Events [Abstract]
SUBSEQUENT EVENT	SUBSEQUENT EVENT On April 30, 2018, Allegiance announced the signing of a definitive merger agreement with Post Oak Bancshares, Inc. (“Post Oak”), the holding company of Post Oak Bank, N.A., whereby Post Oak will be merged with and into Allegiance. Post Oak operates thirteen ( 13 ) banking locations: twelve ( 12 ) located throughout the greater Houston MSA and one in Beaumont, just outside of the Houston MSA. As of March 31, 2018, Post Oak, on a consolidated basis, reported total assets of $1.43 billion , total loans of $1.15 billion and total deposits of $1.24 billion . Under the terms of the definitive agreement, Allegiance will issue 0.7017 shares of Allegiance common stock for each outstanding share of, and option to purchase a share of, Post Oak capital stock, subject to certain conditions and potential adjustments. The merger has been approved by the boards of directors of both companies and is expected to close during the fourth quarter of 2018, although delays may occur. The transaction is subject to certain conditions, including the approval by Allegiance and Post Oak shareholders and customary regulatory approvals. Operational integration is anticipated to begin during the first quarter of 2019.

NATURE OF OPERATIONS AND SUMM22

NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING AND REPORTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation -The accompanying unaudited condensed consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP") for interim financial information and in accordance with guidance provided by the Securities and Exchange Commission. Accordingly, the condensed consolidated financial statements do not include all of the information and footnotes required by GAAP for complete financial statements. The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates. In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all adjustments considered necessary for a fair presentation of the financial position, results of operations and cash flows of the Company on a consolidated basis, and all such adjustments are of a normal recurring nature. Transactions with Allegiance have been eliminated. The condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and footnotes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017 . Operating results for the three months ended March 31, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018 .
New Accounting Standards and Newly Issued But Not Yet Effective Accounting Standards	New Accounting Standards Adoption of New Accounting St andards ASU 2014-09 “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 supersedes the revenue recognition requirements in Revenue Recognition (Topic 605), and most industry-specific guidance throughout the Industry Topics of the Codification. The core principle of ASU 2014-09 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The Company records revenue from contracts with customers in accordance with Accounting Standards Codification Topic 606, “Revenue from Contracts with Customers” (“Topic 606”). Under Topic 606, the Company must identify the contract with a customer, identify the performance obligations in the contract, determine the transaction price, allocate the transaction price to the performance obligations in the contract, and recognize revenue when (or as) the Company satisfies a performance obligation. Significant revenue has not been recognized in the current reporting period that results from performance obligations satisfied in previous periods. The Company’s primary sources of revenue are derived from interest and dividends earned on loans, investment securities, and other financial instruments that are not within the scope of ASU 2014-09. The Company has evaluated the nature of its contracts with customers and determined that further disaggregation of revenue from contracts with customers into more granular categories beyond what is presented in the Consolidated Statements of Income was not necessary. The Company generally fully satisfies its performance obligations on its contracts with customers as services are rendered and the transaction prices are typically fixed, charged either on a periodic basis or based on activity. Because performance obligations are satisfied as services are rendered and the transaction prices are fixed, there is little judgment involved in applying Topic 606 that significantly affects the determination of the amount and timing of revenue from contracts with customers. The new standard was effective for the Company on January 1, 2018 and did not have a significant impact on its consolidated financial statements and related disclosures. ASU No. 2016-01, "Financial Instruments - Overall (Subtopic 825-10): Recognition of Financial Assets and Financial Liabilities." ASU 2016-01 makes targeted amendments to fair value measurement and disclosure guidance. ASU 2016-01 requires equity investments (other than equity method investments) to be measured at fair value with changes in fair value recognized in net income. This change is only applied if a readily determinable fair value can be obtained. The update also requires the use of exit prices to measure fair value for disclosure purposes as well as other enhanced disclosure requirements. ASU 2016-01 was effective for the Company on January 1, 2018 and did not have a significant impact on its financial statements and related disclosures. See Note 5 – Fair Value Disclosures for further information. ASU 2016-15, “Statement of Cash Flows (Topic 230) - Classification of Certain Cash Receipts and Cash Payments." ASU 2016-15 provides guidance related to certain cash flow issues in order to reduce the current and potential future diversity in practice. Among other things, the update clarifies the appropriate classification for proceeds from settlement of bank owned life insurance (BOLI) policies. Based on preliminary assessments, the Company expects to change the classification of proceeds from settlement of BOLI policies, if any, from operating activities to investing activities. ASU 2016-15 was effective for the Company on January 1, 2018 and did not have a significant impact on its financial statements and related disclosures. ASU 2018-02, “Income Statement - Reporting Comprehensive Income (Topic 220) - Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” ASU 2018-02 amends ASC 220, Income Statement - Reporting Comprehensive Income, to allow a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act. On December 22, 2017, the United States enacted tax reform legislation commonly known as the Tax Cuts and Jobs Act (the “Tax Act”), resulting in significant modifications to existing law. Authoritative guidance and interpretation by regulatory bodies is ongoing, and as such, the accounting for the effects of the Tax Act is not final and the full impact of the new regulation is still being evaluated. ASU 2018-02 is effective on January 1, 2019, with early adoption permitted. The Company early adopted and recognized a decrease to retained earnings of $72 thousand due to a reclassification on January 1, 2018. Newly Issued But Not Yet Effective Accounting Standards ASU 2016-02 “Leases (Topic 842)." 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, certain changes were made to align, where necessary, lessor accounting with the lessee accounting model and ASC Topic 606, “Revenue from Contracts with Customers.” ASU 2016-02 will be effective for the Company on January 1, 2019 and will require transition using a modified retrospective approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. Early application of this ASU is permitted for all entities. Adoption of ASU 2016-02 is not expected to have a material impact on the Company’s financial statements. The Company leases certain properties and equipment under operating leases that will result in the recognition of lease assets and lease liabilities on the Company’s balance sheet under the ASU. ASU 2016-13, “Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” Among other things, ASU 2016-13 requires the measurement of all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions and reasonable and supportable forecasts. Financial institutions and other organizations will now use forward-looking information to better form their credit loss estimates. Many of the loss estimation techniques applied today will still be permitted, although the inputs to those techniques will change to reflect the full amount of expected credit losses. In addition, ASU 2016-13 amends the accounting for credit losses on available for sale debt securities and purchased financial assets with credit deterioration. ASU 2016-13 is effective for the Company on January 1, 2020 and must be applied using the modified retrospective approach with limited exceptions. Early adoption is permitted for fiscal years, and interim periods within those years, beginning after December 15, 2018. While the Company is currently unable to reasonably estimate the impact of adopting ASU 2016-13, the Company expects that the impact of adoption will be significantly influenced by the composition, characteristics and quality of its loan and securities portfolios as well as the prevailing economic conditions and forecasts as of the adoption date. The Company has formed a cross functional team and with the assistance of a third-party provider is assessing the Company's data and system needs to evaluate the impact that adoption of this standard will have on the financial condition and results of operations of the Company. ASU No. 2017-04, “Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment,” ASU 2017-04 eliminates Step 2 from the goodwill impairment test which required entities to compute the implied fair value of goodwill. Under ASU 2017-04, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. ASU 2017-04 will be effective for the Company on January 1, 2020, with earlier adoption permitted and is not expected to have a significant impact on the Company's financial statements. ASU 2017-08,“Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20) - Premium Amortization on Purchased Callable Debt Securities.” ASU 2017-08 shortens the amortization period for certain callable debt securities held at a premium to require such premiums to be amortized to the earliest call date unless applicable guidance related to certain pools of securities is applied to consider estimated prepayments. Under prior guidance, entities were generally required to amortize premiums on individual, non-pooled callable debt securities as a yield adjustment over the contractual life of the security. ASU 2017-08 does not change the accounting for callable debt securities held at a discount. ASU 2017-08 will be effective for the Company on January 1, 2019, with early adoption permitted. The Company is currently evaluating the potential impact of ASU 2017-08 on its financial statements.

GOODWILL AND CORE DEPOSIT INT23

GOODWILL AND CORE DEPOSIT INTANGIBLE ASSETS (Tables)	3 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets and Goodwill	Changes in the carrying amount of the Company’s goodwill and core deposit intangible assets were as follows: Goodwill Core Deposit Intangibles (Dollars in thousands) Balance as of January 1, 2017 $ 39,389 $ 4,055 Amortization — (781 ) Balance as of December 31, 2017 39,389 3,274 Amortization — (195 ) Balance as of March 31, 2018 $ 39,389 $ 3,079
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	The estimated aggregate future amortization expense for core deposit intangible assets remaining as of March 31, 2018 is as follows (dollars in thousands): Remaining 2018 $ 586 2019 781 2020 744 2021 484 2022 484 Thereafter — Total $ 3,079

SECURITIES (Tables)

SECURITIES (Tables)	3 Months Ended
	Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Available-for-sale Securities	The amortized cost and fair value of investment securities were as follows: March 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (Dollars in thousands) Available for Sale U.S. Government and agency securities $ 8,299 $ 142 $ (59 ) $ 8,382 Municipal securities 221,403 1,166 (4,281 ) 218,288 Agency mortgage-backed pass-through securities 36,197 74 (954 ) 35,317 Corporate bonds and other 46,077 — (653 ) 45,424 Total $ 311,976 $ 1,382 $ (5,947 ) $ 307,411 December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (Dollars in thousands) Available for Sale U.S. Government and agency securities $ 8,507 $ 232 $ (24 ) $ 8,715 Municipal securities 222,330 2,470 (1,842 ) 222,958 Agency mortgage-backed pass-through securities 32,014 159 (361 ) 31,812 Corporate bonds and other 46,247 62 (179 ) 46,130 Total $ 309,098 $ 2,923 $ (2,406 ) $ 309,615
Investments Classified by Contractual Maturity Date	The amortized cost and fair value of investment securities at March 31, 2018 , by contractual maturity, are shown below. Expected maturities may differ from contractual maturities if borrowers have the right to call or prepay obligations at any time with or without call or prepayment penalties. Amortized Cost Fair Value (Dollars in thousands) Due in one year or less $ 11,873 $ 11,873 Due after one year through five years 71,990 71,051 Due after five years through ten years 92,765 91,478 Due after ten years 99,151 97,692 Subtotal 275,779 272,094 Agency mortgage-backed pass through securities 36,197 35,317 Total $ 311,976 $ 307,411
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	Securities with unrealized losses segregated by length of time such securities have been in a continuous loss position are as follows: March 31, 2018 Less than 12 Months More than 12 Months Total Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses (Dollars in thousands) Available for Sale U.S. Government and agency securities $ 3,342 $ (34 ) $ 531 $ (25 ) $ 3,873 $ (59 ) Municipal securities 100,904 (2,015 ) 55,389 (2,266 ) 156,293 (4,281 ) Agency mortgage-backed pass-through securities 20,426 (507 ) 8,461 (447 ) 28,887 (954 ) Corporate bonds and other 44,424 (653 ) — — 44,424 (653 ) Total $ 169,096 $ (3,209 ) $ 64,381 $ (2,738 ) $ 233,477 $ (5,947 ) December 31, 2017 Less than 12 Months More than 12 Months Total Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses Estimated Fair Value Unrealized Losses (Dollars in thousands) Available for Sale U.S. Government and agency securities $ 3,110 $ (9 ) $ 595 $ (15 ) $ 3,705 $ (24 ) Municipal securities 42,249 (517 ) 56,483 (1,325 ) 98,732 (1,842 ) Agency mortgage-backed pass-through securities 13,238 (105 ) 8,921 (256 ) 22,159 (361 ) Corporate bonds and other 30,203 (179 ) — — 30,203 (179 ) Total $ 88,800 $ (810 ) $ 65,999 $ (1,596 ) $ 154,799 $ (2,406 )

LOANS AND ALLOWANCE FOR LOAN 25

LOANS AND ALLOWANCE FOR LOAN LOSSES (Tables)	3 Months Ended
	Mar. 31, 2018
Loans and Allowance for Loan Losses [Abstract]
Schedule of Accounts, Notes, Loans and Financing Receivable	The loan portfolio balances, net of unearned income and fees, consist of various types of loans primarily made to borrowers located within Texas and are classified by major type as follows: March 31, December 31, (Dollars in thousands) Commercial and industrial $ 447,168 $ 457,129 Mortgage warehouse 41,572 69,456 Real estate: Commercial real estate (including multi-family residential) 1,108,537 1,080,247 Commercial real estate construction and land development 257,566 243,389 1-4 family residential (including home equity) 317,842 301,219 Residential construction 108,882 109,116 Consumer and other 8,927 10,320 Total loans 2,290,494 2,270,876 Allowance for loan losses (24,628 ) (23,649 ) Loans, net $ 2,265,866 $ 2,247,227
Past Due Financing Receivables	An aging analysis of the recorded investment in past due loans, segregated by class of loans, is as follows: March 31, 2018 Loans Past Due and Still Accruing 30-89 Days 90 or More Days Total Past Due Loans Nonaccrual Loans Current Loans Total Loans (Dollars in thousands) Commercial and industrial $ 1,545 $ — $ 1,545 $ 6,153 $ 439,470 $ 447,168 Mortgage warehouse — — — — 41,572 41,572 Real estate: Commercial real estate (including multi-family residential) 699 — 699 6,466 1,101,372 1,108,537 Commercial real estate construction and land development 75 — 75 — 257,491 257,566 1-4 family residential (including home equity) 1,164 — 1,164 754 315,924 317,842 Residential construction 1,787 — 1,787 — 107,095 108,882 Consumer and other 25 — 25 — 8,902 8,927 Total loans $ 5,295 $ — $ 5,295 $ 13,373 $ 2,271,826 $ 2,290,494 December 31, 2017 Loans Past Due and Still Accruing 30-89 Days 90 or More Days Total Past Due Loans Nonaccrual Loans Current Loans Total Loans (Dollars in thousands) Commercial and industrial $ 1,069 $ — $ 1,069 $ 6,437 $ 449,623 $ 457,129 Mortgage warehouse — — — — 69,456 69,456 Real estate: Commercial real estate (including multi-family residential) 4,932 — 4,932 6,110 1,069,205 1,080,247 Commercial real estate construction and land development 5,274 — 5,274 — 238,115 243,389 1-4 family residential (including home equity) 924 — 924 781 299,514 301,219 Residential construction 674 — 674 — 108,442 109,116 Consumer and other 74 — 74 — 10,246 10,320 Total loans $ 12,947 $ — $ 12,947 $ 13,328 $ 2,244,601 $ 2,270,876
Impaired Financing Receivables	Impaired loans by class of loans are set forth in the following tables. March 31, 2018 Recorded Investment Unpaid Principal Balance Related Allowance (Dollars in thousands) With no related allowance recorded: Commercial and industrial $ 4,036 $ 4,519 $ — Mortgage warehouse — — — Real estate: Commercial real estate (including multi-family residential) 10,940 10,941 — Commercial real estate construction and land development 209 209 — 1-4 family residential (including home equity) 910 910 — Residential construction — — — Consumer and other — — — Total 16,095 16,579 — With an allowance recorded: Commercial and industrial 7,047 7,443 2,723 Mortgage warehouse — — — Real estate: Commercial real estate (including multi-family residential) 7,919 8,104 569 Commercial real estate construction and land development — — — 1-4 family residential (including home equity) — — — Residential construction — — — Consumer and other — — — Total 14,966 15,547 3,292 Total: Commercial and industrial 11,083 11,962 2,723 Mortgage warehouse — — — Real estate: Commercial real estate (including multi-family residential) 18,859 19,045 569 Commercial real estate construction and land development 209 209 — 1-4 family residential (including home equity) 910 910 — Residential construction — — — Consumer and other — — — $ 31,061 $ 32,126 $ 3,292 December 31, 2017 Recorded Investment Unpaid Principal Balance Related Allowance (Dollars in thousands) With no related allowance recorded: Commercial and industrial $ 5,792 $ 6,666 $ — Mortgage warehouse — — — Real estate: Commercial real estate (including multi-family residential) 12,155 12,155 — Commercial real estate construction and land development 209 209 — 1-4 family residential (including home equity) 948 948 — Residential construction — — — Consumer and other — — — Total 19,104 19,978 — With an allowance recorded: Commercial and industrial 5,600 5,652 1,640 Mortgage warehouse — — — Real estate: Commercial real estate (including multi-family residential) 8,009 8,194 716 Commercial real estate construction and land development — — — 1-4 family residential (including home equity) — — — Residential construction — — — Consumer and other — — — Total 13,609 13,846 2,356 Total: Commercial and industrial 11,392 12,318 1,640 Mortgage warehouse — — — Real estate: Commercial real estate (including multi-family residential) 20,164 20,349 716 Commercial real estate construction and land development 209 209 — 1-4 family residential (including home equity) 948 948 — Residential construction — — — Consumer and other — — — $ 32,713 $ 33,824 $ 2,356 The following table presents average impaired loans and interest recognized on impaired loans for the three months ended March 31, 2018 and 2017: Three Months Ended March 31, 2018 2017 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income (Dollars in thousands) Commercial and industrial $ 11,461 $ 94 $ 15,742 $ 139 Mortgage warehouse — — — — Real estate: Commercial real estate (including multi-family residential) 18,967 141 16,854 77 Commercial real estate construction and land development 209 3 72 — 1-4 family residential (including home equity) 927 4 575 1 Residential construction — — — — Consumer and other — — 14 — Total $ 31,564 $ 242 $ 33,257 $ 217
Financing Receivable Credit Quality Indicators	Based on the most recent analysis performed, the risk category of loans by class of loan at March 31, 2018 is as follows: Pass Watch Special Mention Substandard Doubtful Total (Dollars in thousands) Commercial and industrial $ 419,105 $ 10,115 $ 1,610 $ 16,338 $ — $ 447,168 Mortgage warehouse 41,572 — — — — 41,572 Real estate: Commercial real estate (including multi-family residential) 1,045,532 24,830 3,067 35,108 — 1,108,537 Commercial real estate construction and land development 245,815 4,345 — 7,406 — 257,566 1-4 family residential (including home equity) 311,603 3,024 1,278 1,937 — 317,842 Residential construction 104,987 3,895 — — — 108,882 Consumer and other 8,851 75 — 1 — 8,927 Total loans $ 2,177,465 $ 46,284 $ 5,955 $ 60,790 $ — $ 2,290,494 The following table presents the risk category of loans by class of loan at December 31, 2017 : Pass Watch Special Mention Substandard Doubtful Total (Dollars in thousands) Commercial and industrial $ 427,336 $ 10,274 $ 2,195 $ 17,324 $ — $ 457,129 Mortgage warehouse 69,456 — — — — 69,456 Real estate: Commercial real estate (including multi-family residential) 1,016,831 23,039 4,685 35,692 — 1,080,247 Commercial real estate construction and land development 231,536 4,397 — 7,456 — 243,389 1-4 family residential (including home equity) 295,744 2,696 785 1,994 — 301,219 Residential construction 103,611 5,505 — — — 109,116 Consumer and other 10,207 111 — 2 — 10,320 Total loans $ 2,154,721 $ 46,022 $ 7,665 $ 62,468 $ — $ 2,270,876
Allowance for Credit Losses on Financing Receivables	The following table presents the activity in the allowance for loan losses by portfolio type for the three months ended March 31, 2018 and 2017 : Commercial and industrial Mortgage warehouse Commercial real estate (including multi-family residential) Commercial real estate construction and land development 1-4 family residential (including home equity) Residential construction Consumer and other Total (Dollars in thousands) Allowance for loan losses: Three Months Ended Balance December 31, 2017 $ 7,694 $ — $ 10,253 $ 2,525 $ 2,140 $ 942 $ 95 $ 23,649 Provision for loan losses 1,440 — (963 ) 20 160 4 (8 ) 653 Charge-offs (367 ) — (40 ) — — — — (407 ) Recoveries 631 — 102 — — — — 733 Net recoveries 264 — 62 — — — — 326 Balance March 31, 2018 $ 9,398 $ — $ 9,352 $ 2,545 $ 2,300 $ 946 $ 87 $ 24,628 Allowance for loan losses: Three Months Ended Balance December 31, 2016 $ 5,059 $ — $ 8,950 $ 1,217 $ 1,876 $ 748 $ 61 $ 17,911 Provision for loan losses 806 — 208 391 (40 ) (11 ) (11 ) 1,343 Charge-offs (627 ) — — — — — — (627 ) Recoveries 46 — — — 10 — 4 60 Net charge-offs (581 ) — — — 10 — 4 (567 ) Balance March 31, 2017 $ 5,284 $ — $ 9,158 $ 1,608 $ 1,846 $ 737 $ 54 $ 18,687 The following table presents the balance of the allowance for loan losses by portfolio type based on the impairment method as of March 31, 2018 and December 31, 2017 : Commercial and industrial Mortgage warehouse Commercial real estate (including multi-family residential) Commercial real estate construction and land development 1-4 family residential (including home equity) Residential construction Consumer and other Total (Dollars in thousands) Allowance for loan losses related to: March 31, 2018 Individually evaluated for impairment $ 2,723 $ — $ 569 $ — $ — $ — $ — $ 3,292 Collectively evaluated for impairment 6,675 — 8,783 2,545 2,300 946 87 21,336 Total allowance for loan losses $ 9,398 $ — $ 9,352 $ 2,545 $ 2,300 $ 946 $ 87 $ 24,628 December 31, 2017 Individually evaluated for impairment $ 1,640 $ — $ 716 $ — $ — $ — $ — $ 2,356 Collectively evaluated for impairment 6,054 — 9,537 2,525 2,140 942 95 21,293 Total allowance for loan losses $ 7,694 $ — $ 10,253 $ 2,525 $ 2,140 $ 942 $ 95 $ 23,649 The following table presents the recorded investment in loans held for investment by portfolio type based on the impairment method as of March 31, 2018 and December 31, 2017 : Commercial and industrial Mortgage warehouse Commercial real estate (including multi-family residential) Commercial real estate construction and land development 1-4 family residential (including home equity) Residential construction Consumer and other Total (Dollars in thousands) Recorded investment in loans: March 31, 2018 Individually evaluated for impairment $ 11,083 $ — $ 18,859 $ 209 $ 910 $ — $ — $ 31,061 Collectively evaluated for impairment 436,085 41,572 1,089,678 257,357 316,932 108,882 8,927 2,259,433 Total loans evaluated for impairment $ 447,168 $ 41,572 $ 1,108,537 $ 257,566 $ 317,842 $ 108,882 $ 8,927 $ 2,290,494 December 31, 2017 Individually evaluated for impairment $ 11,392 $ — $ 20,164 $ 209 $ 948 $ — $ — $ 32,713 Collectively evaluated for impairment 445,737 69,456 1,060,083 243,180 300,271 109,116 10,320 2,238,163 Total loans evaluated for impairment $ 457,129 $ 69,456 $ 1,080,247 $ 243,389 $ 301,219 $ 109,116 $ 10,320 $ 2,270,876
Troubled Debt Restructurings on Financing Receivables	The following tables present information regarding loans modified in a troubled debt restructuring during the three months ended March 31, 2018 and 2017: As of March 31, 2018 2017 Number of Contracts Pre-modification of Outstanding Recorded Investment Post-modification of Outstanding Recorded Investment Number of Contracts Pre-modification of Outstanding Recorded Investment Post-modification of Outstanding Recorded Investment (Dollars in thousands) Troubled Debt Restructurings Commercial and industrial 6 337 337 1 316 316 Mortgage warehouse — — — — — — Real estate: Commercial real estate (including multi-family residential) — — — 1 1,328 1,328 Commercial real estate construction and land development — — — — — — 1-4 family residential (including home equity) — — — 1 86 86 Residential construction — — — — — — Consumer and other — — — — — — Total 6 337 337 3 1,730 1,730

FAIR VALUE (Tables)

FAIR VALUE (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value, by Balance Sheet Grouping	The carrying amounts and estimated fair values of financial instruments that are reported on the balance sheet are as follows: As of March 31, 2018 Carrying Estimated Fair Value Amount Level 1 Level 2 Level 3 Total (Dollars in thousands) Financial assets Cash and cash equivalents $ 190,088 $ 190,088 $ — $ — $ 190,088 Available for sale securities 307,411 — 307,411 — 307,411 Loans held for investment, net of allowance 2,265,866 — — 2,257,861 2,257,861 FHLB stock 14,128 N/A N/A N/A N/A Accrued interest receivable 10,521 2 2,060 8,459 10,521 Financial liabilities Deposits $ 2,284,802 $ — $ 2,276,516 $ — $ 2,276,516 Accrued interest payable 1,212 — 1,212 — 1,212 Borrowed funds 232,569 — 237,498 — 237,498 Subordinated debt and subordinated debentures 48,719 — 48,719 — 48,719 As of December 31, 2017 Carrying Estimated Fair Value Amount Level 1 Level 2 Level 3 Total (Dollars in thousands) Financial assets Cash and cash equivalents $ 182,103 $ 182,103 $ — $ — $ 182,103 Available for sale securities 309,615 — 309,615 — 309,615 Loans held for investment, net of allowance 2,247,227 — — 2,238,721 2,238,721 FHLB stock 12,862 N/A N/A N/A N/A Accrued interest receivable 12,194 3 3,296 8,895 12,194 Financial liabilities Deposits $ 2,213,974 $ — $ 2,209,111 $ — $ 2,209,111 Accrued interest payable 610 — 610 — 610 Borrowed funds 282,569 — 288,887 — 288,887 Subordinated debt and subordinated debentures 48,659 — 48,659 — 48,659
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following tables present fair values for assets measured at fair value on a recurring basis: As of March 31, 2018 Level 1 Level 2 Level 3 Total (Dollars in thousands) Available for sale securities: U.S. Government and agency securities $ — $ 8,382 $ — $ 8,382 Municipal securities — 218,288 — 218,288 Agency mortgage-backed pass-through securities — 35,317 — 35,317 Corporate bonds and other — 45,424 — 45,424 Total $ — $ 307,411 $ — $ 307,411 As of December 31, 2017 Level 1 Level 2 Level 3 Total (Dollars in thousands) Available for sale securities: U.S. Government and agency securities $ — $ 8,715 $ — $ 8,715 Municipal securities — 222,958 — 222,958 Agency mortgage-backed pass-through securities — 31,812 — 31,812 Corporate bonds and other — 46,130 — 46,130 Total $ — $ 309,615 $ — $ 309,615
Fair Value Measurements, Nonrecurring	Certain assets and liabilities are measured at fair value on a nonrecurring basis; that is, the instruments are not measured at fair value on an ongoing basis, but are subject to fair value adjustments in certain circumstances such as evidence of impairment. As of March 31, 2018 Level 1 Level 2 Level 3 (Dollars in thousands) Impaired loans: Commercial and industrial $ — $ — $ 4,720 Commercial real estate (including multi-family residential) — — 7,535 Other real estate owned — — 365 $ — $ — $ 12,620 As of December 31, 2017 Level 1 Level 2 Level 3 (Dollars in thousands) Impaired loans: Commercial and industrial $ — $ — $ 4,012 Commercial real estate (including multi-family residential) — — 7,478 Other real estate owned — — 365 $ — $ — $ 11,855

DEPOSITS (Tables)

DEPOSITS (Tables)	3 Months Ended
	Mar. 31, 2018
Deposit Liabilities [Abstract]
Schedule of Maturities of Time Deposits	Scheduled maturities of time deposits for the next five years are as follows (dollars in thousands): Within one year $ 575,405 After one but within two years 112,102 After two but within three years 38,811 After three but within four years 36,764 After four but within five years 99,695 Total $ 862,777

BORROWINGS AND BORROWING CAPA28

BORROWINGS AND BORROWING CAPACITY (Tables)	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Schedule of Maturities of Long-term Debt	Scheduled principal maturities are as follows (dollars in thousands): Remaining 2018 $ — 2019 — 2020 — 2021 569 Total $ 569

SUBORDINATED DEBT (Tables)

SUBORDINATED DEBT (Tables)	3 Months Ended
	Mar. 31, 2018
Subordinated Borrowings [Abstract]
Schedule of Subordinated Borrowing	A summary of pertinent information related to the Company’s issues of junior subordinated debentures outstanding at March 31, 2018 is set forth in the table below: Description Issuance Date Trust Preferred Securities Outstanding Interest Rate (1) Junior Subordinated Debt Owed to Trusts Maturity Date (2) (Dollars in thousands) Farmers & Merchants Capital Trust II November 13, 2003 $ 7,500 3 month LIBOR + 3.00% $ 7,732 November 8, 2033 Farmers & Merchants Capital Trust III June 30, 2005 3,500 3 month LIBOR + 1.80% 3,609 July 7, 2035 (1) The 3-month LIBOR in effect as of March 31, 2018 was 2.1796% . (2) All debentures are currently callable.

STOCK BASED COMPENSATION (Table

STOCK BASED COMPENSATION (Tables)	3 Months Ended
	Mar. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Share-based Compensation, Stock Options, Activity	A summary of the activity in the stock option plan during the three months ended March 31, 2018 is set forth below: Number of Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (In thousands) (In years) (In thousands) Options outstanding, January 1, 2018 775 $ 19.94 5.72 $ 13,718 Options granted 4 40.40 Options exercised (74 ) 12.94 Options forfeited (9 ) 29.10 Options outstanding, March 31, 2018 696 $ 20.72 5.82 $ 12,850 Options vested and exercisable, March 31, 2018 475 $ 18.00 4.83 $ 10,043
Schedule of Share-based Compensation, Restricted Stock Units Award Activity	A summary of the activity of the nonvested shares of restricted stock during the three months ended March 31, 2018 is as follows: Number of Shares Weighted Average Grant Date Fair Value (Shares in thousands) Nonvested share awards outstanding, January 1, 2018 41 $ 30.46 Share awards granted — 40.40 Share awards vested (10 ) 23.66 Unvested share awards forfeited — — Nonvested share awards outstanding, March 31, 2018 31 $ 31.49

OFF-BALANCE SHEET ARRANGEMENT31

OFF-BALANCE SHEET ARRANGEMENTS, COMMITMENTS AND CONTINGENCIES (Tables)	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Fair Value, Off-balance Sheet Risks	The contractual amounts of financial instruments with off-balance sheet risk are as follows: March 31, 2018 December 31, 2017 Fixed Rate Variable Rate Fixed Rate Variable Rate (Dollars in thousands) Commitments to extend credit $ 254,424 $ 342,980 $ 369,573 $ 250,467 Standby letters of credit 15,212 1,725 15,445 1,725 Total $ 269,636 $ 344,705 $ 385,018 $ 252,192

REGULATORY CAPITAL MATTERS (Tab

REGULATORY CAPITAL MATTERS (Tables)	3 Months Ended
	Mar. 31, 2018
Banking and Thrift [Abstract]
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations	The following is a summary of the Company’s and the Bank’s actual and required capital ratios at March 31, 2018 and December 31, 2017 : Actual Minimum Required For Capital Adequacy Purposes Minimum Required Plus Capital To Be Categorized As Well Capitalized Under Prompt Corrective Action Provisions Amount Ratio Amount Ratio Amount Ratio Amount Ratio (Dollars in thousands) ALLEGIANCE BANCSHARES, INC. (Consolidated) As of March 31, 2018 Total Capital (to risk weighted assets) $ 346,474 13.72 % $ 201,989 8.00 % $ 249,330 9.875 % N/A N/A Common Equity Tier 1 Capital (to risk weighted assets) 273,127 10.82 % 113,619 4.50 % 160,960 6.375 % N/A N/A Tier I Capital (to risk weighted assets) 282,458 11.19 % 151,492 6.00 % 198,833 7.875 % N/A N/A Tier I Capital (to average tangible assets) 282,458 9.98 % 113,180 4.00 % 113,180 4.000 % N/A N/A As of December 31, 2017 Total Capital (to risk weighted assets) $ 336,829 13.43 % $ 200,687 8.00 % $ 232,044 9.250 % N/A N/A Common Equity Tier 1 Capital (to risk weighted assets) 264,521 10.54 % 112,886 4.50 % 144,244 5.750 % N/A N/A Tier I Capital (to risk weighted assets) 273,825 10.92 % 150,515 6.00 % 181,872 7.250 % N/A N/A Tier I Capital (to average tangible assets) 273,825 9.84 % 111,274 4.00 % 96,708 4.000 % N/A N/A ALLEGIANCE BANK As of March 31, 2018 Total Capital (to risk weighted assets) $ 340,358 13.49 % $ 201,890 8.00 % $ 249,208 9.875 % $ 252,362 10.00 % Common Equity Tier 1 Capital (to risk weighted assets) 276,342 10.95 % 113,563 4.50 % 160,881 6.375 % 164,035 6.50 % Tier I Capital (to risk weighted assets) 276,342 10.95 % 151,417 6.00 % 198,735 7.875 % 201,890 8.00 % Tier I Capital (to average tangible assets) 276,342 9.77 % 113,132 4.00 % 113,132 4.000 % 141,415 5.00 % As of December 31, 2017 Total Capital (to risk weighted assets) $ 331,872 13.24 % $ 200,596 8.00 % $ 231,939 9.250 % $ 250,745 10.00 % Common Equity Tier 1 Capital (to risk weighted assets) 268,868 10.72 % 112,835 4.50 % 144,179 5.750 % 162,985 6.50 % Tier I Capital (to risk weighted assets) 268,868 10.72 % 150,447 6.00 % 181,790 7.250 % 200,596 8.00 % Tier I Capital (to average tangible assets) 268,868 9.67 % 111,230 4.00 % 111,230 4.000 % 139,037 5.00 %

EARNINGS PER COMMON SHARE (Tabl

EARNINGS PER COMMON SHARE (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	Restricted shares are considered outstanding at the date of grant, accounted for as participating securities and included in basic and diluted weighted average common shares outstanding. Three Months Ended March 31, 2018 2017 Amount Per Share Amount Amount Per Share Amount (Amounts in thousands, except per share data) Net income attributable to common shareholders $ 7,711 $ 6,047 Basic: Weighted average common shares outstanding 13,262 $ 0.58 13,021 $ 0.46 Diluted: Add incremental shares for: Dilutive effect of stock option exercises 280 356 Total 13,542 $ 0.57 13,377 $ 0.45

NATURE OF OPERATIONS AND SUMM34

NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING AND REPORTING POLICIES (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)office
Accounting Policies [Abstract]
Number of offices in which entity operates | office	16
Number of loan production offices in which entity operates | office	1
New Accounting Pronouncement, Early Adoption [Line Items]
Cumulative effect of new accounting principle in period of adoption | $	$ 72
Retained Earnings
New Accounting Pronouncement, Early Adoption [Line Items]
Cumulative effect of new accounting principle in period of adoption | $	$ 72

GOODWILL AND CORE DEPOSIT INT35

GOODWILL AND CORE DEPOSIT INTANGIBLE ASSETS - Changes in Carrying Amount of Goodwill and Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Goodwill
Balance, beginning	$ 39,389	$ 39,389	$ 39,389
Balance, ending	39,389		39,389
Core Deposit Intangibles
Balance, beginning	3,274
Amortization	(195)	(195)
Balance, ending	3,079		3,274
Core Deposit Intangibles
Core Deposit Intangibles
Balance, beginning	3,274	$ 4,055	4,055
Amortization	(195)		(781)
Balance, ending	$ 3,079		$ 3,274

GOODWILL AND CORE DEPOSIT INT36

GOODWILL AND CORE DEPOSIT INTANGIBLE ASSETS - Narrative, Acquisitions (Details)	Mar. 31, 2018USD ($)
Acquisition of F&M
Business Acquisition [Line Items]
Goodwill impairment	$ 0

GOODWILL AND CORE DEPOSIT INT37

GOODWILL AND CORE DEPOSIT INTANGIBLE ASSETS - Estimated Aggregate Future Amortization Expense for Core Deposit Intangibles (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Remaining 2,018	$ 586
2,019	781
2,020	744
2,021	484
2,022	484
Thereafter	0
Total	$ 3,079	$ 3,274

SECURITIES - Amortized Cost and

SECURITIES - Amortized Cost and Fair Value of Investment Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 311,976	$ 309,098
Gross Unrealized Gains	1,382	2,923
Gross Unrealized Losses	(5,947)	(2,406)
Fair Value	307,411	309,615
U.S. Government and agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,299	8,507
Gross Unrealized Gains	142	232
Gross Unrealized Losses	(59)	(24)
Fair Value	8,382	8,715
Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	221,403	222,330
Gross Unrealized Gains	1,166	2,470
Gross Unrealized Losses	(4,281)	(1,842)
Fair Value	218,288	222,958
Agency mortgage-backed pass-through securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	36,197	32,014
Gross Unrealized Gains	74	159
Gross Unrealized Losses	(954)	(361)
Fair Value	35,317	31,812
Corporate bonds and other
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	46,077	46,247
Gross Unrealized Gains	0	62
Gross Unrealized Losses	(653)	(179)
Fair Value	$ 45,424	$ 46,130

SECURITIES - Amortized Cost a39

SECURITIES - Amortized Cost and Fair Value of Investment Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Amortized Cost
Due in one year or less	$ 11,873
Due after one year through five years	71,990
Due after five years through ten years	92,765
Due after ten years	99,151
Subtotal	275,779
Agency mortgage-backed pass through securities	36,197
Total	311,976
Fair Value
Due in one year or less	11,873
Due after one year through five years	71,051
Due after five years through ten years	91,478
Due after ten years	97,692
Subtotal	272,094
Agency mortgage-backed pass through securities	35,317
Total	$ 307,411	$ 309,615

SECURITIES - Securities in a Co

SECURITIES - Securities in a Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Securities in a Continuous Unrealized Loss Position, Less than 12 months, Estimated Fair Value	$ 169,096	$ 88,800
Securities in a Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(3,209)	(810)
Securities in a Continuous Unrealized Loss Position, More than 12 Months, Estimated Fair Value	64,381	65,999
Securities in a Continuous Unrealized Loss Position, More than 12 Months Unrealized Losses	(2,738)	(1,596)
Securities in a Continuous Unrealized Loss Position, Total Estimated Fair Value	233,477	154,799
Securities in a Continuous Unrealized Loss Position, Total Unrealized Losses	(5,947)	(2,406)
U.S. Government and agency securities
Schedule of Available-for-sale Securities [Line Items]
Securities in a Continuous Unrealized Loss Position, Less than 12 months, Estimated Fair Value	3,342	3,110
Securities in a Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(34)	(9)
Securities in a Continuous Unrealized Loss Position, More than 12 Months, Estimated Fair Value	531	595
Securities in a Continuous Unrealized Loss Position, More than 12 Months Unrealized Losses	(25)	(15)
Securities in a Continuous Unrealized Loss Position, Total Estimated Fair Value	3,873	3,705
Securities in a Continuous Unrealized Loss Position, Total Unrealized Losses	(59)	(24)
Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Securities in a Continuous Unrealized Loss Position, Less than 12 months, Estimated Fair Value	100,904	42,249
Securities in a Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(2,015)	(517)
Securities in a Continuous Unrealized Loss Position, More than 12 Months, Estimated Fair Value	55,389	56,483
Securities in a Continuous Unrealized Loss Position, More than 12 Months Unrealized Losses	(2,266)	(1,325)
Securities in a Continuous Unrealized Loss Position, Total Estimated Fair Value	156,293	98,732
Securities in a Continuous Unrealized Loss Position, Total Unrealized Losses	(4,281)	(1,842)
Agency mortgage-backed pass-through securities
Schedule of Available-for-sale Securities [Line Items]
Securities in a Continuous Unrealized Loss Position, Less than 12 months, Estimated Fair Value	20,426	13,238
Securities in a Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(507)	(105)
Securities in a Continuous Unrealized Loss Position, More than 12 Months, Estimated Fair Value	8,461	8,921
Securities in a Continuous Unrealized Loss Position, More than 12 Months Unrealized Losses	(447)	(256)
Securities in a Continuous Unrealized Loss Position, Total Estimated Fair Value	28,887	22,159
Securities in a Continuous Unrealized Loss Position, Total Unrealized Losses	(954)	(361)
Corporate bonds and other
Schedule of Available-for-sale Securities [Line Items]
Securities in a Continuous Unrealized Loss Position, Less than 12 months, Estimated Fair Value	44,424	30,203
Securities in a Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(653)	(179)
Securities in a Continuous Unrealized Loss Position, More than 12 Months, Estimated Fair Value	0	0
Securities in a Continuous Unrealized Loss Position, More than 12 Months Unrealized Losses	0	0
Securities in a Continuous Unrealized Loss Position, Total Estimated Fair Value	44,424	30,203
Securities in a Continuous Unrealized Loss Position, Total Unrealized Losses	$ (653)	$ (179)

SECURITIES - Narrative (Details

SECURITIES - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Security owned and pledged as collateral	$ 5	$ 5

LOANS AND ALLOWANCE FOR LOAN 42

LOANS AND ALLOWANCE FOR LOAN LOSSES - Loan Portfolio (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 2,290,494	$ 2,270,876
Allowance for loan losses	(24,628)	(23,649)	$ (18,687)	$ (17,911)
Loans, net	2,265,866	2,247,227
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	447,168	457,129
Allowance for loan losses	(9,398)	(7,694)	(5,284)	(5,059)
Mortgage warehouse
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	41,572	69,456
Allowance for loan losses	0	0	0	0
Real estate | Commercial real estate (including multi-family residential)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,108,537	1,080,247
Real estate | Commercial real estate construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	257,566	243,389
Real estate | 1-4 family residential (including home equity)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	317,842	301,219
Real estate | Residential construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	108,882	109,116
Consumer and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	8,927	10,320
Allowance for loan losses	$ (87)	$ (95)	$ (54)	$ (61)

LOANS AND ALLOWANCE FOR LOAN 43

LOANS AND ALLOWANCE FOR LOAN LOSSES - Aging Analysis of the Recorded Investment in Past Due Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	$ 5,295	$ 12,947
Nonaccrual Loans	13,373	13,328
Current Loans	2,271,826	2,244,601
Total loans evaluated for impairment	2,290,494	2,270,876
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	1,545	1,069
Nonaccrual Loans	6,153	6,437
Current Loans	439,470	449,623
Total loans evaluated for impairment	447,168	457,129
Mortgage warehouse
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	0	0
Nonaccrual Loans	0	0
Current Loans	41,572	69,456
Total loans evaluated for impairment	41,572	69,456
Real estate | Commercial real estate (including multi-family residential)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	699	4,932
Nonaccrual Loans	6,466	6,110
Current Loans	1,101,372	1,069,205
Total loans evaluated for impairment	1,108,537	1,080,247
Real estate | Commercial real estate construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	75	5,274
Nonaccrual Loans	0	0
Current Loans	257,491	238,115
Total loans evaluated for impairment	257,566	243,389
Real estate | 1-4 family residential (including home equity)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	1,164	924
Nonaccrual Loans	754	781
Current Loans	315,924	299,514
Total loans evaluated for impairment	317,842	301,219
Real estate | Residential construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	1,787	674
Nonaccrual Loans	0	0
Current Loans	107,095	108,442
Total loans evaluated for impairment	108,882	109,116
Consumer and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	25	74
Nonaccrual Loans	0	0
Current Loans	8,902	10,246
Total loans evaluated for impairment	8,927	10,320
Financing Receivables, 30 to 89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	5,295	12,947
Financing Receivables, 30 to 89 Days Past Due | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	1,545	1,069
Financing Receivables, 30 to 89 Days Past Due | Mortgage warehouse
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	0	0
Financing Receivables, 30 to 89 Days Past Due | Real estate | Commercial real estate (including multi-family residential)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	699	4,932
Financing Receivables, 30 to 89 Days Past Due | Real estate | Commercial real estate construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	75	5,274
Financing Receivables, 30 to 89 Days Past Due | Real estate | 1-4 family residential (including home equity)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	1,164	924
Financing Receivables, 30 to 89 Days Past Due | Real estate | Residential construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	1,787	674
Financing Receivables, 30 to 89 Days Past Due | Consumer and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	25	74
Financing Receivables, Equal to Greater than 90 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due | Mortgage warehouse
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due | Real estate | Commercial real estate (including multi-family residential)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due | Real estate | Commercial real estate construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due | Real estate | 1-4 family residential (including home equity)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due | Real estate | Residential construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due | Consumer and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Past Due and Still Accruing	$ 0	$ 0

LOANS AND ALLOWANCE FOR LOAN 44

LOANS AND ALLOWANCE FOR LOAN LOSSES - Impaired Loans by Loan Class (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
With no related allowance recorded:
Recorded investment with no related allowance recorded	$ 16,095	$ 19,104
Unpaid principal balance with no related allowance recorded	16,579	19,978
With an allowance recorded:
Impaired financing receivable, with related allowance, recorded investment	14,966	13,609
Impaired financing receivable, with related allowance, unpaid principal balance	15,547	13,846
Related Allowance	3,292	2,356
Total:
Recorded Investment	31,061	32,713
Unpaid Principal Balance	32,126	33,824
Related Allowance	3,292	2,356
Commercial and industrial
With no related allowance recorded:
Recorded investment with no related allowance recorded	4,036	5,792
Unpaid principal balance with no related allowance recorded	4,519	6,666
With an allowance recorded:
Impaired financing receivable, with related allowance, recorded investment	7,047	5,600
Impaired financing receivable, with related allowance, unpaid principal balance	7,443	5,652
Related Allowance	2,723	1,640
Total:
Recorded Investment	11,083	11,392
Unpaid Principal Balance	11,962	12,318
Related Allowance	2,723	1,640
Mortgage warehouse
With no related allowance recorded:
Recorded investment with no related allowance recorded	0	0
Unpaid principal balance with no related allowance recorded	0	0
With an allowance recorded:
Impaired financing receivable, with related allowance, recorded investment	0	0
Impaired financing receivable, with related allowance, unpaid principal balance	0	0
Related Allowance	0	0
Total:
Recorded Investment	0	0
Unpaid Principal Balance	0	0
Related Allowance	0	0
Real estate | Commercial real estate (including multi-family residential)
With no related allowance recorded:
Recorded investment with no related allowance recorded	10,940	12,155
Unpaid principal balance with no related allowance recorded	10,941	12,155
With an allowance recorded:
Impaired financing receivable, with related allowance, recorded investment	7,919	8,009
Impaired financing receivable, with related allowance, unpaid principal balance	8,104	8,194
Related Allowance	569	716
Total:
Recorded Investment	18,859	20,164
Unpaid Principal Balance	19,045	20,349
Related Allowance	569	716
Real estate | Commercial real estate construction and land development
With no related allowance recorded:
Recorded investment with no related allowance recorded	209	209
Unpaid principal balance with no related allowance recorded	209	209
With an allowance recorded:
Impaired financing receivable, with related allowance, recorded investment	0	0
Impaired financing receivable, with related allowance, unpaid principal balance	0	0
Related Allowance	0	0
Total:
Recorded Investment	209	209
Unpaid Principal Balance	209	209
Related Allowance	0	0
Real estate | 1-4 family residential (including home equity)
With no related allowance recorded:
Recorded investment with no related allowance recorded	910	948
Unpaid principal balance with no related allowance recorded	910	948
With an allowance recorded:
Impaired financing receivable, with related allowance, recorded investment	0	0
Impaired financing receivable, with related allowance, unpaid principal balance	0	0
Related Allowance	0	0
Total:
Recorded Investment	910	948
Unpaid Principal Balance	910	948
Related Allowance	0	0
Real estate | Residential construction
With no related allowance recorded:
Recorded investment with no related allowance recorded	0	0
Unpaid principal balance with no related allowance recorded	0	0
With an allowance recorded:
Impaired financing receivable, with related allowance, recorded investment	0	0
Impaired financing receivable, with related allowance, unpaid principal balance	0	0
Related Allowance	0	0
Total:
Recorded Investment	0	0
Unpaid Principal Balance	0	0
Related Allowance	0	0
Consumer and other
With no related allowance recorded:
Recorded investment with no related allowance recorded	0	0
Unpaid principal balance with no related allowance recorded	0	0
With an allowance recorded:
Impaired financing receivable, with related allowance, recorded investment	0	0
Impaired financing receivable, with related allowance, unpaid principal balance	0	0
Related Allowance	0	0
Total:
Recorded Investment	0	0
Unpaid Principal Balance	0	0
Related Allowance	$ 0	$ 0

LOANS AND ALLOWANCE FOR LOAN 45

LOANS AND ALLOWANCE FOR LOAN LOSSES - Average Impaired Loans and Interest Recognized (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	$ 31,564	$ 33,257
Interest Income Recognized	242	217
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	11,461	15,742
Interest Income Recognized	94	139
Mortgage warehouse
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Real estate | Commercial real estate (including multi-family residential)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	18,967	16,854
Interest Income Recognized	141	77
Real estate | Commercial real estate construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	209	72
Interest Income Recognized	3	0
Real estate | 1-4 family residential (including home equity)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	927	575
Interest Income Recognized	4	1
Real estate | Residential construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Consumer and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	0	14
Interest Income Recognized	$ 0	$ 0

LOANS AND ALLOWANCE FOR LOAN 46

LOANS AND ALLOWANCE FOR LOAN LOSSES - Risk Category of Loans by Class (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 2,290,494	$ 2,270,876
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	447,168	457,129
Mortgage warehouse
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	41,572	69,456
Real estate | Commercial real estate (including multi-family residential)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,108,537	1,080,247
Real estate | Commercial real estate construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	257,566	243,389
Real estate | 1-4 family residential (including home equity)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	317,842	301,219
Real estate | Residential construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	108,882	109,116
Consumer and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	8,927	10,320
Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,177,465	2,154,721
Pass | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	419,105	427,336
Pass | Mortgage warehouse
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	41,572	69,456
Pass | Real estate | Commercial real estate (including multi-family residential)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,045,532	1,016,831
Pass | Real estate | Commercial real estate construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	245,815	231,536
Pass | Real estate | 1-4 family residential (including home equity)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	311,603	295,744
Pass | Real estate | Residential construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	104,987	103,611
Pass | Consumer and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	8,851	10,207
Watch
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	46,284	46,022
Watch | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	10,115	10,274
Watch | Mortgage warehouse
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	0	0
Watch | Real estate | Commercial real estate (including multi-family residential)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	24,830	23,039
Watch | Real estate | Commercial real estate construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	4,345	4,397
Watch | Real estate | 1-4 family residential (including home equity)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	3,024	2,696
Watch | Real estate | Residential construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	3,895	5,505
Watch | Consumer and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	75	111
Special Mention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	5,955	7,665
Special Mention | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,610	2,195
Special Mention | Mortgage warehouse
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	0	0
Special Mention | Real estate | Commercial real estate (including multi-family residential)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	3,067	4,685
Special Mention | Real estate | Commercial real estate construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	0	0
Special Mention | Real estate | 1-4 family residential (including home equity)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,278	785
Special Mention | Real estate | Residential construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	0	0
Special Mention | Consumer and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	0	0
Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	60,790	62,468
Substandard | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	16,338	17,324
Substandard | Mortgage warehouse
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	0	0
Substandard | Real estate | Commercial real estate (including multi-family residential)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	35,108	35,692
Substandard | Real estate | Commercial real estate construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	7,406	7,456
Substandard | Real estate | 1-4 family residential (including home equity)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,937	1,994
Substandard | Real estate | Residential construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	0	0
Substandard | Consumer and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1	2
Doubtful
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	0	0
Doubtful | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	0	0
Doubtful | Mortgage warehouse
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	0	0
Doubtful | Real estate | Commercial real estate (including multi-family residential)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	0	0
Doubtful | Real estate | Commercial real estate construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	0	0
Doubtful | Real estate | 1-4 family residential (including home equity)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	0	0
Doubtful | Real estate | Residential construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	0	0
Doubtful | Consumer and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 0	$ 0

LOANS AND ALLOWANCE FOR LOAN 47

LOANS AND ALLOWANCE FOR LOAN LOSSES - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Dec. 31, 2017
Allowance for loan losses:
Balance, beginning of period	$ 23,649	$ 17,911
Provision for loan losses	653	1,343
Charge-offs	(407)	(627)
Recoveries	733	60
Net recoveries (charge-offs)	326	(567)
Balance, end of period	24,628	18,687
Allowance for loan losses related to:
Individually evaluated for impairment			$ 3,292	$ 2,356
Collectively evaluated for impairment			21,336	21,293
Total allowance for loan losses	23,649	17,911	24,628	23,649
Recorded investment in loans:
Individually evaluated for impairment			31,061	32,713
Collectively evaluated for impairment			2,259,433	2,238,163
Total loans evaluated for impairment			2,290,494	2,270,876
Commercial and industrial
Allowance for loan losses:
Balance, beginning of period	7,694	5,059
Provision for loan losses	1,440	806
Charge-offs	(367)	(627)
Recoveries	631	46
Net recoveries (charge-offs)	264	(581)
Balance, end of period	9,398	5,284
Allowance for loan losses related to:
Individually evaluated for impairment			2,723	1,640
Collectively evaluated for impairment			6,675	6,054
Total allowance for loan losses	7,694	5,059	9,398	7,694
Recorded investment in loans:
Individually evaluated for impairment			11,083	11,392
Collectively evaluated for impairment			436,085	445,737
Total loans evaluated for impairment			447,168	457,129
Mortgage warehouse
Allowance for loan losses:
Balance, beginning of period	0	0
Provision for loan losses	0	0
Charge-offs	0	0
Recoveries	0	0
Net recoveries (charge-offs)	0	0
Balance, end of period	0	0
Allowance for loan losses related to:
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			0	0
Total allowance for loan losses	0	0	0	0
Recorded investment in loans:
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			41,572	69,456
Total loans evaluated for impairment			41,572	69,456
Commercial real estate (including multi-family residential) | Commercial real estate (including multi-family residential)
Allowance for loan losses:
Balance, beginning of period	10,253	8,950
Provision for loan losses	(963)	208
Charge-offs	(40)	0
Recoveries	102	0
Net recoveries (charge-offs)	62	0
Balance, end of period	9,352	9,158
Allowance for loan losses related to:
Individually evaluated for impairment			569	716
Collectively evaluated for impairment			8,783	9,537
Total allowance for loan losses	10,253	8,950	9,352	10,253
Recorded investment in loans:
Individually evaluated for impairment			18,859	20,164
Collectively evaluated for impairment			1,089,678	1,060,083
Total loans evaluated for impairment			1,108,537	1,080,247
Commercial real estate (including multi-family residential) | Commercial real estate construction and land development
Allowance for loan losses:
Balance, beginning of period	2,525	1,217
Provision for loan losses	20	391
Charge-offs	0	0
Recoveries	0	0
Net recoveries (charge-offs)	0	0
Balance, end of period	2,545	1,608
Allowance for loan losses related to:
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			2,545	2,525
Total allowance for loan losses	2,525	1,217	2,545	2,525
Recorded investment in loans:
Individually evaluated for impairment			209	209
Collectively evaluated for impairment			257,357	243,180
Total loans evaluated for impairment			257,566	243,389
Commercial real estate (including multi-family residential) | 1-4 family residential (including home equity)
Allowance for loan losses:
Balance, beginning of period	2,140	1,876
Provision for loan losses	160	(40)
Charge-offs	0	0
Recoveries	0	10
Net recoveries (charge-offs)	0	10
Balance, end of period	2,300	1,846
Allowance for loan losses related to:
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			2,300	2,140
Total allowance for loan losses	2,140	1,876	2,300	2,140
Recorded investment in loans:
Individually evaluated for impairment			910	948
Collectively evaluated for impairment			316,932	300,271
Total loans evaluated for impairment			317,842	301,219
Commercial real estate (including multi-family residential) | Residential construction
Allowance for loan losses:
Balance, beginning of period	942	748
Provision for loan losses	4	(11)
Charge-offs	0	0
Recoveries	0	0
Net recoveries (charge-offs)	0	0
Balance, end of period	946	737
Allowance for loan losses related to:
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			946	942
Total allowance for loan losses	942	748	946	942
Recorded investment in loans:
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			108,882	109,116
Total loans evaluated for impairment			108,882	109,116
Consumer and other
Allowance for loan losses:
Balance, beginning of period	95	61
Provision for loan losses	(8)	(11)
Charge-offs	0	0
Recoveries	0	4
Net recoveries (charge-offs)	0	4
Balance, end of period	87	54
Allowance for loan losses related to:
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			87	95
Total allowance for loan losses	$ 95	$ 61	87	95
Recorded investment in loans:
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			8,927	10,320
Total loans evaluated for impairment			$ 8,927	$ 10,320

LOANS AND ALLOWANCE FOR LOAN 48

LOANS AND ALLOWANCE FOR LOAN LOSSES - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Loans and Allowance for Loan Losses [Abstract]
Recorded investment	$ 25,400		$ 25,600
Change in method of calculating impairment	1,900		$ 2,200
Troubled debt restructuring, write-down	17	$ 395
Troubled debt restructuring, addition	337
Troubled debt restructuring, addition, outstanding	$ 314

LOANS AND ALLOWANCE FOR LOAN 49

LOANS AND ALLOWANCE FOR LOAN LOSSES - Loans Modified in a Troubled Debt Restructuring (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018USD ($)contract	Dec. 31, 2017USD ($)contract
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	6	3
Pre- Modification of Outstanding Recorded Investment	$ 337	$ 1,730
Post- Modification of Outstanding Recorded Investment	$ 337	$ 1,730
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	6	1
Pre- Modification of Outstanding Recorded Investment	$ 337	$ 316
Post- Modification of Outstanding Recorded Investment	$ 337	$ 316
Mortgage warehouse
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	0	0
Pre- Modification of Outstanding Recorded Investment	$ 0	$ 0
Post- Modification of Outstanding Recorded Investment	$ 0	$ 0
Real estate | Commercial real estate (including multi-family residential)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	0	1
Pre- Modification of Outstanding Recorded Investment	$ 0	$ 1,328
Post- Modification of Outstanding Recorded Investment	$ 0	$ 1,328
Real estate | Commercial real estate construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	0	0
Pre- Modification of Outstanding Recorded Investment	$ 0	$ 0
Post- Modification of Outstanding Recorded Investment	$ 0	$ 0
Real estate | 1-4 family residential (including home equity)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	0	1
Pre- Modification of Outstanding Recorded Investment	$ 0	$ 86
Post- Modification of Outstanding Recorded Investment	$ 0	$ 86
Real estate | Residential construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	0	0
Pre- Modification of Outstanding Recorded Investment	$ 0	$ 0
Post- Modification of Outstanding Recorded Investment	$ 0	$ 0
Consumer and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | contract	0	0
Pre- Modification of Outstanding Recorded Investment	$ 0	$ 0
Post- Modification of Outstanding Recorded Investment	$ 0	$ 0

FAIR VALUE - Carrying Amounts a

FAIR VALUE - Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	$ 307,411	$ 309,615
FHLB stock	14,128	12,862
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	190,088	182,103
Available for sale securities	307,411	309,615
Loans held for investment, net of allowance	2,265,866	2,247,227
FHLB stock	14,128	12,862
Accrued interest receivable	10,521	12,194
Deposits	2,284,802	2,213,974
Accrued interest payable	1,212	610
Borrowed funds	232,569	282,569
Subordinated debt and subordinated debentures	48,719	48,659
Estimated Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	190,088	182,103
Available for sale securities	307,411	309,615
Loans held for investment, net of allowance	2,257,861	2,238,721
Accrued interest receivable	10,521	12,194
Deposits	2,276,516	2,209,111
Accrued interest payable	1,212	610
Borrowed funds	237,498	288,887
Subordinated debt and subordinated debentures	48,719	48,659
Estimated Fair Value | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	190,088	182,103
Available for sale securities	0	0
Loans held for investment, net of allowance	0	0
Accrued interest receivable	2	3
Deposits	0	0
Accrued interest payable	0	0
Borrowed funds	0	0
Subordinated debt and subordinated debentures	0	0
Estimated Fair Value | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Available for sale securities	307,411	309,615
Loans held for investment, net of allowance	0	0
Accrued interest receivable	2,060	3,296
Deposits	2,276,516	2,209,111
Accrued interest payable	1,212	610
Borrowed funds	237,498	288,887
Subordinated debt and subordinated debentures	48,719	48,659
Estimated Fair Value | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Available for sale securities	0	0
Loans held for investment, net of allowance	2,257,861	2,238,721
Accrued interest receivable	8,459	8,895
Deposits	0	0
Accrued interest payable	0	0
Borrowed funds	0	0
Subordinated debt and subordinated debentures	$ 0	$ 0

FAIR VALUE - Fair Values for As

FAIR VALUE - Fair Values for Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	$ 307,411	$ 309,615
U.S. Government and agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	8,382	8,715
Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	218,288	222,958
Agency mortgage-backed pass-through securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	35,317	31,812
Corporate bonds and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	45,424	46,130
Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	307,411	309,615
Recurring Basis | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0	0
Recurring Basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	307,411	309,615
Recurring Basis | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0	0
Recurring Basis | U.S. Government and agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	8,382	8,715
Recurring Basis | U.S. Government and agency securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0	0
Recurring Basis | U.S. Government and agency securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	8,382	8,715
Recurring Basis | U.S. Government and agency securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0	0
Recurring Basis | Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	218,288	222,958
Recurring Basis | Municipal securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0	0
Recurring Basis | Municipal securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	218,288	222,958
Recurring Basis | Municipal securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0	0
Recurring Basis | Agency mortgage-backed pass-through securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	35,317	31,812
Recurring Basis | Agency mortgage-backed pass-through securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0	0
Recurring Basis | Agency mortgage-backed pass-through securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	35,317	31,812
Recurring Basis | Agency mortgage-backed pass-through securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0	0
Recurring Basis | Corporate bonds and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	45,424	46,130
Recurring Basis | Corporate bonds and other | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	0	0
Recurring Basis | Corporate bonds and other | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	45,424	46,130
Recurring Basis | Corporate bonds and other | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	$ 0	$ 0

FAIR VALUE - Narrative (Details

FAIR VALUE - Narrative (Details) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, fair value disclosure, recurring	$ 0	$ 0
Impaired financing receivable, with related allowance, recorded investment	14,966,000	13,609,000
Impaired financing receivable, with related allowance, unpaid principal balance	15,547,000	13,846,000
Related allowance	3,292,000	2,356,000
Other real estate owned	365,000	365,000
Recorded investment of commercial real estate land loans	0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired financing receivable, with related allowance, recorded investment	12,300,000	11,500,000
Impaired financing receivable, with related allowance, unpaid principal balance	15,500,000	13,800,000
Related allowance	3,300,000	2,400,000
Other real estate owned	$ 365,000	$ 365,000

FAIR VALUE - Assets and Liabili

FAIR VALUE - Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets and liabilities are measured at fair value, nonrecurring basis	$ 0	$ 0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets and liabilities are measured at fair value, nonrecurring basis	0	0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets and liabilities are measured at fair value, nonrecurring basis	12,620	11,855
Nonrecurring Basis | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	0	0
Nonrecurring Basis | Level 1 | Commercial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans:	0	0
Nonrecurring Basis | Level 1 | Commercial real estate (including multi-family residential)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans:	0	0
Nonrecurring Basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	0	0
Nonrecurring Basis | Level 2 | Commercial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans:	0	0
Nonrecurring Basis | Level 2 | Commercial real estate (including multi-family residential)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans:	0	0
Nonrecurring Basis | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	365	365
Nonrecurring Basis | Level 3 | Commercial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans:	4,720	4,012
Nonrecurring Basis | Level 3 | Commercial real estate (including multi-family residential)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans:	$ 7,535	$ 7,478

DEPOSITS - Narrative (Details)

DEPOSITS - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Deposit Liabilities [Abstract]
Time deposits 250,000 or more	$ 260.6	$ 227.4
Brokered deposits	243.2	314.8
Reciprocal deposits	$ 73.1	$ 68.4

DEPOSITS - Time Deposits by Mat

DEPOSITS - Time Deposits by Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Deposit Liabilities [Abstract]
Within one year	$ 575,405
After one but within two years	112,102
After two but within three years	38,811
After three but within four years	36,764
After four but within five years	99,695
Total	$ 862,777	$ 761,314

BORROWINGS AND BORROWING CAPA56

BORROWINGS AND BORROWING CAPACITY - Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended		12 Months Ended
	Oct. 31, 2015	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Increase (decrease) in other borrowings				$ 18,000,000	$ 10,100,000
Repayments of debt	$ 27,500,000	$ 50,000,000	$ 10,000,000
Borrowing Agreement | Prime Rate
Debt Instrument [Line Items]
Basis spread on variable rate		0.25%
Interest rate, effective percentage		4.25%
Federal Home Loan Bank of Dallas
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 1,000,000,000
Remaining borrowing capacity		702,400,000
Outstanding amount		298,900,000
Letters of credit, outstanding amount		66,900,000
Federal Home Loan Bank of Dallas | Expire in July 2018
Debt Instrument [Line Items]
Letters of credit, outstanding amount		7,100,000
Federal Home Loan Bank of Dallas | Expire in August 2018
Debt Instrument [Line Items]
Letters of credit, outstanding amount		15,100,000
Federal Home Loan Bank of Dallas | Expire in September 2018
Debt Instrument [Line Items]
Letters of credit, outstanding amount		7,000,000
Federal Home Loan Bank of Dallas | Expire in October 2018
Debt Instrument [Line Items]
Letters of credit, outstanding amount		25,000,000
Federal Home Loan Bank of Dallas | Expire in December 2018
Debt Instrument [Line Items]
Letters of credit, outstanding amount		6,100,000
Federal Home Loan Bank of Dallas | Expire in January 2019
Debt Instrument [Line Items]
Letters of credit, outstanding amount		1,700,000
Federal Home Loan Bank of Dallas | Expire in February 2019
Debt Instrument [Line Items]
Letters of credit, outstanding amount		3,100,000
Federal Home Loan Bank of Dallas | Expire in December 2019
Debt Instrument [Line Items]
Letters of credit, outstanding amount		300,000
Federal Home Loan Bank of Dallas | Expire in January 2020
Debt Instrument [Line Items]
Letters of credit, outstanding amount		1,500,000
Federal Home Loan Bank of Dallas | Short-term Debt
Debt Instrument [Line Items]
Federal Home Loan Bank, advances		$ 232,000,000
Federal Home Loan Bank of Dallas | Short-term Debt | Weighted Average
Debt Instrument [Line Items]
Federal Home Loan Bank, advances, interest rate		1.91%

BORROWINGS AND BORROWING CAPA57

BORROWINGS AND BORROWING CAPACITY - Scheduled Principal Maturities (Details) $ in Thousands	Mar. 31, 2018USD ($)
Debt Disclosure [Abstract]
Remaining 2,018	$ 0
2,019	0
2,020	0
2,021	569
Total	$ 569

SUBORDINATED DEBT - Narrative (

SUBORDINATED DEBT - Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended
	Dec. 31, 2017	Mar. 31, 2018
Subordinated Borrowing [Line Items]
Debentures, period over which company may defer interest payments		5 years
Junior subordinated debt owed to trusts		$ 11,300,000
Junior Subordinated Debt | Subordinated Notes Issued 2017
Subordinated Borrowing [Line Items]
Debt instrument, face amount	$ 40,000,000
Issuance price, percentage	100.00%
Proceeds from issuance of debt	$ 39,400,000
Stated percentage	5.25%
Redemption price, percentage	100.00%
Junior Subordinated Debt | Subordinated Notes Issued 2017 | 3 month LIBOR
Subordinated Borrowing [Line Items]
Basis spread on variable rate	3.03%
F&M Bancshares. Inc. | Junior Subordinated Debt
Subordinated Borrowing [Line Items]
Debt instrument, face amount		11,300,000
Borrowed funds		9,300,000
Debt instrument, unamortized discount		$ 2,500,000

SUBORDINATED DEBT - Summary of

SUBORDINATED DEBT - Summary of Pertinent Information Related to Junior Subordinated Debentures (Details)	3 Months Ended
	Mar. 31, 2018USD ($)
Subordinated Borrowing [Line Items]
Junior Subordinated Debt Owed to Trusts	$ 11,300,000
Junior Subordinated Debt | 3 month LIBOR
Subordinated Borrowing [Line Items]
Interest rate, period end	2.1796%
Junior Subordinated Debt | Farmers & Merchants Capital Trust II
Subordinated Borrowing [Line Items]
Issuance Date	Nov. 13, 2003
Trust Preferred Securities Outstanding	$ 7,500,000
Junior Subordinated Debt Owed to Trusts	$ 7,732,000
Maturity Date	Nov. 8, 2033
Junior Subordinated Debt | Farmers & Merchants Capital Trust II | 3 month LIBOR
Subordinated Borrowing [Line Items]
Interest Rate	3.00%
Junior Subordinated Debt | Farmers & Merchants Capital Trust III
Subordinated Borrowing [Line Items]
Issuance Date	Jun. 30, 2005
Trust Preferred Securities Outstanding	$ 3,500,000
Junior Subordinated Debt Owed to Trusts	$ 3,609,000
Maturity Date	Jul. 7, 2035
Junior Subordinated Debt | Farmers & Merchants Capital Trust III | 3 month LIBOR
Subordinated Borrowing [Line Items]
Interest Rate	1.80%

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Income tax expense	$ 1,454,000	$ 1,530,000
Effective income tax rate reconciliation, percent	15.90%	20.20%
Unrecognized tax benefits, income tax penalties and interest expense	$ 0	$ 0

STOCK BASED COMPENSATION - Narr

STOCK BASED COMPENSATION - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of shares authorized (in shares)		1,900,000
Share-based compensation expense	$ 438	$ 341
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option, cumulative options granted since inception (in shares)	1,309,231
Expiration period	10 years
Award vesting period	4 years
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	4 years
Equity instruments other than options, grants in period (in shares)	300

STOCK BASED COMPENSATION - Stoc

STOCK BASED COMPENSATION - Stock Option Plan Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Number of Options
Options outstanding, beginning balance (in shares)	775
Options granted (in shares)	4
Options exercised (in shares)	(74)
Options forfeited (in shares)	(9)
Options outstanding, ending balance (in shares)	696	775
Number of options vested and exercisable (in shares)	475
Weighted Average Exercise Price
Options outstanding, beginning balance (in dollars per share)	$ 19.94
Options granted (in dollars per share)	40.40
Options exercised (in dollars per share)	12.94
Options forfeited (in dollars per share)	29.10
Options outstanding, ending balance (in dollars per share)	20.72	$ 19.94
Weighted Average Exercise Price, Options vested and exercisable (in dollars per share)	$ 18
Weighted Average Remaining Contractual Term, Options outstanding	5 years 9 months 26 days	5 years 8 months 19 days
Weighted Average Remaining Contractual Term, Options vested and exercisable	4 years 9 months 29 days
Aggregate Intrinsic Value, Options outstanding	$ 12,850	$ 13,718
Aggregate Intrinsic Value, Options vested and exercisable	$ 10,043

STOCK BASED COMPENSATION - Summ

STOCK BASED COMPENSATION - Summary of Restricted Stock Activity (Details) - Restricted Stock shares in Thousands	3 Months Ended
	Mar. 31, 2018$ / sharesshares
Number of Shares
Nonvested share awards outstanding, beginning balance (in shares) | shares	41
Share awards granted (in shares) | shares	0
Share awards vested (in shares) | shares	(10)
Unvested share awards forfeited (in shares) | shares	0
Nonvested share awards outstanding, ending balance (in shares) | shares	31
Weighted Average Grant Date Fair Value
Nonvested share awards outstanding, beginning balance (in dollars per share) | $ / shares	$ 30.46
Share awards granted (in dollars per share) | $ / shares	40.40
Share awards vested (in dollars per share) | $ / shares	23.66
Unvested share awards forfeited (in dollars per share) | $ / shares	0
Nonvested share awards outstanding, ending balance (in dollars per share) | $ / shares	$ 31.49

OFF-BALANCE SHEET ARRANGEMENT64

OFF-BALANCE SHEET ARRANGEMENTS, COMMITMENTS AND CONTINGENCIES - Contractual Amounts of Financial Instruments With Off-balance Sheet Risk (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fixed Rate	$ 269,636	$ 385,018
Variable Rate	344,705	252,192
Commitments to extend credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fixed Rate	254,424	369,573
Variable Rate	342,980	250,467
Standby letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fixed Rate	15,212	15,445
Variable Rate	$ 1,725	$ 1,725

OFF-BALANCE SHEET ARRANGEMENT65

OFF-BALANCE SHEET ARRANGEMENTS, COMMITMENTS AND CONTINGENCIES - Narrative (Details)	3 Months Ended
	Mar. 31, 2018
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments to make loans, period	120 days
Off-balance-sheet fixed rate loan commitments, weighted average maturity	2 years 1 month 28 days
Minimum
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance-sheet fixed rate loan commitments, interest rate	1.75%
Maximum
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance-sheet fixed rate loan commitments, interest rate	7.50%
Weighted Average
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance-sheet fixed rate loan commitments, interest rate	5.01%

REGULATORY CAPITAL MATTERS - Na

REGULATORY CAPITAL MATTERS - Narrative (Details)	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2016
Banking and Thrift [Abstract]
Capital conservation buffer, phase in amount			0.625%
Capital conservation buffer, increase per year		0.625%
Forecast
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital conservation buffer	2.50%

REGULATORY CAPITAL MATTERS - Ac

REGULATORY CAPITAL MATTERS - Actual and Required Capital (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Total Capital
Capital	$ 346,474	$ 336,829
Capital to Risk Weighted Assets	13.72%	13.43%
Capital Required for Capital Adequacy	$ 201,989	$ 200,687
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00%	8.00%
Plus Capital Conservation Buffer	$ 249,330	$ 232,044
Plus Capital Conservation Buffer to Risk Weighted Assets	9.875%	9.25%
Common Equity Tier 1 Capital
Common Equity Tier One Risk Based Capital	$ 273,127	$ 264,521
Common Equity Tier One Risk Based Capital to Risk Weighted Assets	10.82%	10.54%
Common Equity Tier One Risk Based Capital Required for Capital Adequacy	$ 113,619	$ 112,886
Common Equity Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	4.50%	4.50%
Plus Common Equity Tier One Risk Based Capital	$ 160,960	$ 144,244
Plus Common Equity Tier One Risk Based Capital to Risk Weighted Assets	6.375%	5.75%
Tier I Capital
Tier One Risk Based Capital	$ 282,458	$ 273,825
Tier One Risk Based Capital to Risk Weighted Assets	11.19%	10.92%
Tier One Risk Based Capital Required for Capital Adequacy	$ 151,492	$ 150,515
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	6.00%	6.00%
Plus Tier One Risk Based Capital	$ 198,833	$ 181,872
Plus Tier One Risk Based Capital to Risk Weighted Assets	7.875%	7.25%
Tier I Capital
Tier One Leverage Capital	$ 282,458	$ 273,825
Tier One Leverage Capital to Average Assets	9.98%	9.84%
Tier One Leverage Capital Required for Capital Adequacy	$ 113,180	$ 111,274
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	4.00%	4.00%
Plus Tier One Leverage Capital	$ 113,180	$ 96,708
Plus Tier One Leverage Capital to Average Assets	4.00%	4.00%
Allegiance Bank
Total Capital
Capital	$ 340,358	$ 331,872
Capital to Risk Weighted Assets	13.49%	13.24%
Capital Required for Capital Adequacy	$ 201,890	$ 200,596
Capital Required for Capital Adequacy to Risk Weighted Assets	8.00%	8.00%
Plus Capital Conservation Buffer	$ 249,208	$ 231,939
Plus Capital Conservation Buffer to Risk Weighted Assets	9.875%	9.25%
Capital Required to be Well Capitalized	$ 252,362	$ 250,745
Capital Required to be Well Capitalized to Risk Weighted Assets	10.00%	10.00%
Common Equity Tier 1 Capital
Common Equity Tier One Risk Based Capital	$ 276,342	$ 268,868
Common Equity Tier One Risk Based Capital to Risk Weighted Assets	10.95%	10.72%
Common Equity Tier One Risk Based Capital Required for Capital Adequacy	$ 113,563	$ 112,835
Common Equity Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	4.50%	4.50%
Plus Common Equity Tier One Risk Based Capital	$ 160,881	$ 144,179
Plus Common Equity Tier One Risk Based Capital to Risk Weighted Assets	6.375%	5.75%
Common Equity Tier One Risk Based Capital Required to be Well Capitalized	$ 164,035	$ 162,985
Common Equity Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	6.50%	6.50%
Tier I Capital
Tier One Risk Based Capital	$ 276,342	$ 268,868
Tier One Risk Based Capital to Risk Weighted Assets	10.95%	10.72%
Tier One Risk Based Capital Required for Capital Adequacy	$ 151,417	$ 150,447
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	6.00%	6.00%
Plus Tier One Risk Based Capital	$ 198,735	$ 181,790
Plus Tier One Risk Based Capital to Risk Weighted Assets	7.875%	7.25%
Tier One Risk Based Capital Required to be Well Capitalized	$ 201,890	$ 200,596
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	8.00%	8.00%
Tier I Capital
Tier One Leverage Capital	$ 276,342	$ 268,868
Tier One Leverage Capital to Average Assets	9.77%	9.67%
Tier One Leverage Capital Required for Capital Adequacy	$ 113,132	$ 111,230
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	4.00%	4.00%
Plus Tier One Leverage Capital	$ 113,132	$ 111,230
Plus Tier One Leverage Capital to Average Assets	4.00%	4.00%
Tier One Leverage Capital Required to be Well Capitalized	$ 141,415	$ 139,037
Tier One Leverage Capital Required to be Well Capitalized to Average Assets	5.00%	5.00%

EARNINGS PER COMMON SHARE - Sum

EARNINGS PER COMMON SHARE - Summary of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Net income attributable to common shareholders	$ 7,711	$ 6,047
Basic:
Weighted average common shares outstanding (in shares)	13,262	13,021
Weighted average common shares outstanding (in dollars per share)	$ 0.58	$ 0.46
Diluted:
Dilutive effect of stock option exercises (in shares)	280	356
Total (in shares)	13,542	13,377
Total (in dollars per share)	$ 0.57	$ 0.45

EARNINGS PER COMMON SHARE - Nar

EARNINGS PER COMMON SHARE - Narrative (Details) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)		0
Employee Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	19,000

SUBSEQUENT EVENT (Details)

SUBSEQUENT EVENT (Details) $ in Thousands	Apr. 30, 2018branch	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Subsequent Event [Line Items]
Total assets		$ 2,886,484	$ 2,860,231
Total loans		2,265,866	2,247,227
Total deposits		2,284,802	$ 2,213,974
Post Oak Bancshares, Inc.
Subsequent Event [Line Items]
Total assets		1,430,000
Total loans		1,150,000
Total deposits		$ 1,240,000
Subsequent Event | Post Oak Bancshares, Inc.
Subsequent Event [Line Items]
Number of branches | branch	13
Number of shares per common share or option to purchase common shares (in shares)	0.7017
Subsequent Event | Post Oak Bancshares, Inc. | Houston, Texas
Subsequent Event [Line Items]
Number of branches | branch	12
Subsequent Event | Post Oak Bancshares, Inc. | Beaumont, TX
Subsequent Event [Line Items]
Number of branches | branch	1