Prosperity Bancshares (PB) 10-Q 7 May 18 2018 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 03, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	PROSPERITY BANCSHARES INC
Entity Central Index Key	1,068,851
Trading Symbol	PB
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large 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)		69,844,886

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks	$ 243,514	$ 391,616
Federal funds sold	469	697
Total cash and cash equivalents	243,983	392,313
Available for sale securities, at fair value	207,489	217,870
Held to maturity securities, at cost (fair value of $9,239,443 and $9,323,482 respectively)	9,502,765	9,454,246
Total securities	9,710,254	9,672,116
Loans held for sale	34,551	31,389
Loans held for investment	9,976,865	9,989,384
Total loans	10,011,416	10,020,773
Less: allowance for credit losses	(83,600)	(84,041)
Loans, net	9,927,816	9,936,732
Accrued interest receivable	51,526	56,368
Goodwill	1,900,845	1,900,845
Core deposit intangibles, net	37,274	38,842
Bank premises and equipment, net	257,057	257,065
Other real estate owned	10,538	11,152
Bank owned life insurance (BOLI)	256,443	255,132
Federal Home Loan Bank of Dallas stock	55,394	49,764
Other assets	21,184	16,963
TOTAL ASSETS	22,472,314	22,587,292
Deposits:
Noninterest-bearing	5,707,994	5,623,322
Interest-bearing	11,624,885	12,198,138
Total deposits	17,332,879	17,821,460
Other borrowings	820,079	505,223
Securities sold under repurchase agreements	339,576	324,154
Accrued interest payable	2,992	2,945
Other liabilities	100,643	109,356
Total liabilities	18,596,169	18,763,138
COMMITMENTS AND CONTINGENCIES
SHAREHOLDERS’ EQUITY:
Preferred stock, $1 par value; 20,000,000 shares authorized; none issued or outstanding
Common stock, $1 par value; 200,000,000 shares authorized; 69,819,286 shares issued and outstanding at March 31, 2018; 69,490,910 shares issued and outstanding at December 31, 2017	69,819	69,491
Capital surplus	2,037,498	2,035,219
Retained earnings	1,768,783	1,719,557
Accumulated other comprehensive income (loss)—net unrealized gain (loss) on available for sale securities, net of tax expense (benefit) of $12 and ($30), respectively	45	(113)
Total shareholders’ equity	3,876,145	3,824,154
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$ 22,472,314	$ 22,587,292

Consolidated Balance Sheets (U3

Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Held to maturity securities, fair value	$ 9,239,443	$ 9,323,482
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	69,819,286	69,490,910
Common stock, shares outstanding (in shares)	69,819,286	69,490,910
Accumulated other comprehensive income (loss)-net unrealized gain (loss) on available for sale securities, tax expense (benefit)	$ 12	$ (30)

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	$ 116,246	$ 111,710
Securities	54,457	53,157
Federal funds sold	315	183
Total interest income	171,018	165,050
INTEREST EXPENSE:
Deposits	14,472	9,908
Other borrowings	2,973	2,476
Securities sold under repurchase agreements	350	231
Total interest expense	17,795	12,615
NET INTEREST INCOME	153,223	152,435
PROVISION FOR CREDIT LOSSES	9,000	2,675
NET INTEREST INCOME AFTER PROVISION FOR CREDIT LOSSES	144,223	149,760
NONINTEREST INCOME:
Nonsufficient funds (NSF) fees	7,827	8,089
Credit card, debit card and ATM card income	5,961	5,953
Service charges on deposit accounts	5,275	5,421
Trust income	2,728	2,155
Mortgage income	763	1,266
Brokerage income	625	488
Net gain on sale of assets		1,759
Other	4,759	5,693
Total noninterest income	27,938	30,824
NONINTEREST EXPENSE:
Salaries and employee benefits	50,399	48,444
Net occupancy and equipment	5,609	5,503
Credit and debit card, data processing and software amortization	4,448	4,085
Regulatory assessments and FDIC insurance	3,575	3,549
Core deposit intangibles amortization	1,568	1,915
Depreciation	3,033	3,103
Communications	2,580	2,702
Other real estate expense	211	85
Other	8,631	8,676
Total noninterest expense	80,054	78,062
INCOME BEFORE INCOME TAXES	92,107	102,522
PROVISION FOR INCOME TAXES	17,746	33,957
NET INCOME	$ 74,361	$ 68,565
EARNINGS PER SHARE:
Basic	$ 1.07	$ 0.99
Diluted	$ 1.07	$ 0.99

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 74,361	$ 68,565
Securities available for sale:
Change in unrealized gain during period	200	29
Total other comprehensive income	200	29
Deferred taxes related to other comprehensive income	(42)	(10)
Other comprehensive income, net of tax	158	19
Comprehensive income	$ 74,519	$ 68,584

Consolidated Statements of Chan

Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]
BALANCE at Dec. 31, 2016	$ 3,642,311	$ 69,491	$ 2,028,129	$ 1,543,280	$ 1,411
BALANCE (in shares) at Dec. 31, 2016		69,491,012
Net income	68,565			68,565
Other comprehensive income	19				19
Common stock issued in connection with the exercise of stock options and restricted stock awards, net	148	$ (11)	159
Common stock issued in connection with the exercise of stock options and restricted stock awards, net (in shares)		(11,100)
Stock based compensation expense	1,662		1,662
Cash dividends declared	(23,623)			(23,623)
BALANCE at Mar. 31, 2017	3,689,082	$ 69,480	2,029,950	1,588,222	1,430
BALANCE (in shares) at Mar. 31, 2017		69,479,912
BALANCE at Dec. 31, 2017	3,824,154	$ 69,491	2,035,219	1,719,557	(113)
BALANCE (in shares) at Dec. 31, 2017		69,490,910
Net income	74,361			74,361
Other comprehensive income	158				158
Common stock issued in connection with the exercise of stock options and restricted stock awards, net		$ 328	(328)
Common stock issued in connection with the exercise of stock options and restricted stock awards, net (in shares)		328,376
Stock based compensation expense	2,607		2,607
Cash dividends declared	(25,135)			(25,135)
BALANCE at Mar. 31, 2018	$ 3,876,145	$ 69,819	$ 2,037,498	$ 1,768,783	$ 45
BALANCE (in shares) at Mar. 31, 2018		69,819,286

Consolidated Statements of Cha7

Consolidated Statements of Changes in Shareholders' Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Retained Earnings [Member]
Cash dividend declared, per share (in dollars per share)	$ 0.36	$ 0.34

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	$ 74,361	$ 68,565
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and core deposit intangibles amortization	4,601	5,018
Provision for credit losses	9,000	2,675
Net amortization of premium on investments	8,450	9,883
Net loss (gain) on sale of other real estate	122	(10)
Net gain on sale of assets		(1,759)
Net accretion of discount on loans	(2,326)	(4,753)
Net amortization of premium on deposits	(53)	(99)
Gain on sale of loans	(705)	(1,162)
Proceeds from sale of loans held for sale	40,916	59,037
Originations of loans held for sale	(43,373)	(52,904)
Stock based compensation expense	2,607	1,662
Increase in accrued interest receivable and other assets	(7,406)	(17,703)
(Decrease) increase in accrued interest payable and other liabilities	(8,666)	75,998
Net cash provided by operating activities	77,528	144,448
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from maturities and principal paydowns of held to maturity securities	440,176	424,808
Purchase of held to maturity securities	(497,004)	(574,333)
Proceeds from maturities and principal paydowns of available for sale securities	1,610,394	1,211,622
Purchase of available for sale securities	(1,599,954)	(1,199,985)
Net decrease (increase) in loans held for investment	5,331	(121,679)
Purchase of bank premises and equipment	(3,078)	(1,123)
Proceeds from sale of bank premises, equipment and other real estate	634	4,401
Proceeds from insurance claims	1,028
Net cash used in investing activities	(42,473)	(256,289)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in noninterest-bearing deposits	84,672	108,291
Net decrease in interest-bearing deposits	(573,200)	(379,922)
Net proceeds from other short-term borrowings	315,000	280,000
Repayments of other long-term borrowings	(144)	(137)
Net increase in securities sold under repurchase agreements	15,422	15,445
Proceeds from stock option exercises	0	148
Payments of cash dividends	(25,135)	(23,623)
Net cash (used in) provided by financing activities	(183,385)	202
NET DECREASE IN CASH AND CASH EQUIVALENTS	(148,330)	(111,639)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	392,313	437,381
CASH AND CASH EQUIVALENTS, END OF PERIOD	243,983	325,742
NONCASH ACTIVITIES:
Acquisition of real estate through foreclosure of collateral	47	320
SUPPLEMENTAL INFORMATION:
Income taxes paid	62,230
Interest paid	$ 17,748	$ 12,706

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	1. BASIS OF PRESENTATION The consolidated financial statements include the accounts of Prosperity Bancshares, Inc. ® ® The accompanying unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for financial information and with the rules and regulations of the Securities and Exchange Commission. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, the statements reflect all adjustments 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. These financial statements and the notes thereto should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2017. Operating results for the three-month period ended March 31, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018 or any other period.

Income Per Common Share

Income Per Common Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Income Per Common Share	2. INCOME PER COMMON SHARE Outstanding stock options issued by the Company represent the only dilutive effect reflected in diluted weighted average shares. The following table illustrates the computation of basic and diluted earnings per share: Three Months Ended March 31, 2018 2017 Amount Per Share Amount Amount Per Share Amount (Amounts in thousands, except per share data) Net income $ 74,361 $ 68,565 Basic: Weighted average shares outstanding 69,768 $ 1.07 69,480 $ 0.99 Diluted: Add incremental shares for: Effect of dilutive securities - options — 2 Total 69,768 $ 1.07 69,482 $ 0.99 There were no stock options exercisable during the three months ended March 31, 2018 or 2017 that would have had an anti-dilutive effect on the above computation.

New Accounting Standards

New Accounting Standards	3 Months Ended
	Mar. 31, 2018
New Accounting Pronouncements And Changes In Accounting Principles [Abstract]
New Accounting Standards	3. NEW ACCOUNTING STANDARDS Accounting Standards Updates (“ASU”) ASU 2018-02, “Income Statement-Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” The amendments of ASU 2018-02 allow a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act. ASU 2018-02 is effective for all entities beginning January 1, 2019 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).” ASU 2017-08 shortens the amortization period for certain callable debt securities held at a premium. Specifically, the amendments require the premium to be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. ASU 2017-08 will be effective for the Company on January 1, 2019 on a modified retrospective basis with a cumulative-effect adjustment as of the beginning of the period of adoption and is not expected to have a significant impact on the Company’s financial statements. ASU 2016-13, “Financial Instruments – Credit Losses (Topic 326)—Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 requires a financial asset (or a group of financial assets) measured at amortized cost basis to be presented at the net amount expected to be collected. The measurement of expected credit losses is based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. An entity must use judgment in determining the relevant information and estimation methods that are appropriate in its circumstances. Additionally, available for sale debt securities may realize value either through collection of contractual cash flows or through sale of the security at fair value. Therefore, the amendments limit the amount of the allowance for credit losses to the difference between amortized cost and fair value. ASU 2016-13 will be effective for the Company as of January 1, 2020. The Company is currently evaluating the potential impact of ASU 2016-13 on the Company’s financial statements. ASU 2016-02, "Leases (Topic 842)." ASU 2016-02 requires that lessees and lessors recognize lease assets and lease liabilities on the balance sheet and disclose key information about leasing arrangements. ASU 2016-02 is effective for public companies for annual periods beginning January 1, 2019, including interim periods within those fiscal years. The Company is currently evaluating the potential impact of ASU 2016-02 on the Company’s financial statements. ASU 2016-01, “Financial Instruments—Overall (Subtopic 825-10)—Recognition and Measurement of Financial Assets and Financial Liabilities.” ASU 2016-01 addresses certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. ASU 2016-01 1) requires equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income; 2) simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; 3) eliminates the requirement to disclose the fair value of financial instruments measured at amortized cost for entities that are not public business entities; 4) eliminates the requirement for public business entities to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet; 5) requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; 6) requires an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments; 7) requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (that is, securities or loans and receivables) on the balance sheet or the accompanying notes to the financial statements; and 8) clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity’s other deferred tax assets. The amendments in this update affect all entities that hold financial assets or owe financial liabilities. ASU 2016-01 became effective for the Company on January 1, 2018, and did not have a material financial impact on the Company’s financial statements. 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. In addition, the FASB has issued targeted updates to clarify specific implementation issues of ASU 2014-09. These updates include ASU 2016-08 - ASU 2016-10 - ASU 2016-12 - and ASU 2016-20 - s. These amendments do not change the core principles in ASU 2014-09. The Company’s primary sources of revenue are comprised of net interest income on financial assets and liabilities, which are not within the scope of ASU 2014-09. The Company completed its overall assessment of revenue streams and review of related contracts potentially affected by the ASU. Based on this assessment, the Company concluded the ASU did not significantly change the method in which the Company currently recognizes revenue. ASU 2014-09 became effective for the Company on January 1, 2018 and did not have a material financial impact on the Company’s financial statements. The following provides further detail on other revenue streams within noninterest income that are within the scope of this update. Nonsufficient Funds (NSF) Fees – NSF fees are generated on a transactional basis from nonsufficient funds. Revenue is recognized once the performance obligation is satisfied. Credit card, debit card and ATM card income – Credit card and debit card income is primarily comprised of interchange fees earned on a transactional basis through card payment networks. ATM card income is generated when the Company’s card holders use foreign ATMs or when non-customers utilize the Company’s ATMs. Revenue is recognized after the performance obligation is satisfied generally after the transaction is completed. Service Charges on Deposit Accounts – Services charges on deposit accounts consist of account maintenance or transaction-based fees. The Company’s performance obligation is satisfied over a period of time for account maintenance and at the time of service for transaction-based fees. Revenue is recognized after the performance obligation is satisfied. Trust Income – Trust income represents monthly income from trust and estate administration, investment management services, and employee benefits services. The Company’s performance obligation is generally performed over a period of time and varies by the type of trust services being provided to the customer. Revenue is recognized after the performance obligation is satisfied. Brokerage Income – Brokerage income represents fees and commissions from asset management services and transaction processing. The Company’s performance obligation is generally performed over a period of time for asset management services and at a point in time for transaction processing. Revenue is recognized after the performance obligation is satisfied.

Securities

Securities	3 Months Ended
	Mar. 31, 2018
Investments Debt And Equity Securities [Abstract]
Securities	4. 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 States and political subdivisions $ 1,668 $ 4 $ — $ 1,672 Collateralized mortgage obligations 95,544 770 (53 ) 96,261 Mortgage-backed securities 97,632 986 (1,331 ) 97,287 Other securities 12,588 — (319 ) 12,269 Total $ 207,432 $ 1,760 $ (1,703 ) $ 207,489 Held to Maturity U.S. Treasury securities and obligations of U.S. Government agencies $ 32,289 $ 43 $ (39 ) $ 32,293 States and political subdivisions 290,040 4,058 (538 ) 293,560 Collateralized mortgage obligations 615 2 (4 ) 613 Mortgage-backed securities 9,179,821 6,063 (272,907 ) 8,912,977 Total $ 9,502,765 $ 10,166 $ (273,488 ) $ 9,239,443 December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (Dollars in thousands) Available for Sale States and political subdivisions $ 1,817 $ 3 $ — $ 1,820 Collateralized mortgage obligations 99,996 122 (57 ) 100,061 Mortgage-backed securities 103,612 1,204 (1,327 ) 103,489 Other securities 12,588 13 (101 ) 12,500 Total $ 218,013 $ 1,342 $ (1,485 ) $ 217,870 Held to Maturity U.S. Treasury securities and obligations of U.S. Government agencies $ 32,235 $ 150 $ (5 ) $ 32,380 States and political subdivisions 328,666 4,263 (807 ) 332,122 Collateralized mortgage obligations 653 2 (5 ) 650 Mortgage-backed securities 9,092,692 9,382 (143,744 ) 8,958,330 Total $ 9,454,246 $ 13,797 $ (144,561 ) $ 9,323,482 Management evaluates securities for other-than-temporary impairment (“OTTI”) at least on a quarterly basis, and more frequently when economic or market conditions warrant such an evaluation. The investment securities portfolio is evaluated for OTTI by segregating the portfolio into two general segments and applying the appropriate OTTI analysis. Investment securities classified as available for sale or held to maturity are evaluated for OTTI under Financial Accounting Standards Board (“FASB”): Accounting Standards Codification (“ASC”) Topic 320, “ Investments-Debt and Equity Securities.” In determining OTTI, management considers many factors, including: (1) the length of time and the extent to which the fair value has been less than cost, (2) the financial condition and near-term prospects of the issuer, (3) whether the market decline was affected by macroeconomic conditions and (4) whether the entity has the intent to sell the debt security or more likely than not will be required to sell the debt security before its anticipated recovery. The assessment of whether an other-than-temporary decline exists involves a high degree of subjectivity and judgment and is based on the information available to management at the time of such determination. When OTTI occurs, the amount of the OTTI recognized in earnings depends on whether an entity intends to sell the security or more likely than not will be required to sell the security before recovery of its amortized cost basis less any current-period credit loss. If an entity intends to sell or more likely than not will be required to sell the security before recovery of its amortized cost basis less any current-period credit loss, the OTTI will be recognized in earnings equal to the entire difference between the investment’s amortized cost basis and its fair value at the balance sheet date. If an entity does not intend to sell the security and it is not more likely than not that the entity will be required to sell the security before recovery of its amortized cost basis less any current-period loss, the OTTI will be separated into the amount representing the credit-related portion of the impairment loss (“credit loss”) and the noncredit portion of the impairment loss (“noncredit portion”). The amount of the total OTTI related to the credit loss is determined based on the difference between the present value of cash flows expected to be collected and the amortized cost basis and such difference is recognized in earnings. The amount of the total OTTI related to the noncredit portion is recognized in other comprehensive income, net of applicable taxes. The previous amortized cost basis less the OTTI recognized in earnings will become the new amortized cost basis of the investment. Management has the ability and intent to hold the securities classified as held-to-maturity until they mature, at which time the Company will receive full value for the securities. Furthermore, as of March 31, 2018, management does not have the intent to sell any of the securities classified as available for sale before a recovery of cost. In addition, management believes it is more likely than not that the Company will not be required to sell any of its investment securities before a recovery of cost. The unrealized losses are largely due to increases in market interest rates over the yields available at the time the underlying securities were purchased. 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 any impairment in the Company’s securities is temporary, and therefore no impairment loss has been recognized in the Company’s consolidated statement of income. Securities with unrealized losses, segregated by length of time, that have been in a continuous loss position were 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 Collateralized mortgage obligations $ 3,479 $ (27 ) $ 2,417 $ (26 ) $ 5,896 $ (53 ) Mortgage-backed securities 40,470 (1,328 ) 1,926 (3 ) 42,396 (1,331 ) Other securities 12,269 (319 ) — — 12,269 (319 ) Total $ 56,218 $ (1,674 ) $ 4,343 $ (29 ) $ 60,561 $ (1,703 ) Held to Maturity U.S. Treasury securities and obligations of U.S. Government agencies $ 25,397 $ (39 ) $ — $ — $ 25,397 $ (39 ) States and political subdivisions 86,764 (513 ) 2,881 (25 ) 89,645 (538 ) Collateralized mortgage obligations 354 (4 ) — — 354 (4 ) Mortgage-backed securities 4,802,646 (106,841 ) 3,669,817 (166,066 ) 8,472,463 (272,907 ) Total $ 4,915,161 $ (107,397 ) $ 3,672,698 $ (166,091 ) $ 8,587,859 $ (273,488 ) 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 Collateralized mortgage obligations $ 5,753 $ (13 ) $ 2,544 $ (44 ) $ 8,297 $ (57 ) Mortgage-backed securities 42,289 (1,323 ) 2,054 (4 ) 44,343 (1,327 ) Other securities 1,636 (101 ) — — 1,636 (101 ) Total $ 49,678 $ (1,437 ) $ 4,598 $ (48 ) $ 54,276 $ (1,485 ) Held to Maturity U.S. Treasury securities and obligations of U.S. Government agencies $ 4,934 $ (5 ) $ — $ — $ 4,934 $ (5 ) States and political subdivisions 160,392 (773 ) 3,686 (34 ) 164,078 (807 ) Collateralized mortgage obligations 373 (2 ) 100 (3 ) 473 (5 ) Mortgage-backed securities 3,940,075 (34,159 ) 3,883,266 (109,585 ) 7,823,341 (143,744 ) Total $ 4,105,774 $ (34,939 ) $ 3,887,052 $ (109,622 ) $ 7,992,826 $ (144,561 ) At March 31, 2018 and December 31, 2017, there were 292 securities and 308 securities, respectively, in an unrealized loss position for more than 12 months. The amortized cost and fair value of investment securities at March 31, 2018, by contractual maturity, are shown below. Actual maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations at any time with or without call or prepayment penalties. Held to Maturity Available for Sale Amortized Cost Fair Value Amortized Cost Fair Value (Dollars in thousands) Due in one year or less $ 37,102 $ 37,237 $ 13,098 $ 12,779 Due after one year through five years 161,835 162,424 1,158 1,162 Due after five years through ten years 113,051 115,623 — — Due after ten years 10,341 10,569 — — Subtotal 322,329 325,853 14,256 13,941 Mortgage-backed securities and collateralized mortgage obligations 9,180,436 8,913,590 193,176 193,548 Total $ 9,502,765 $ 9,239,443 $ 207,432 $ 207,489 The Company recorded no gain or loss on the sale of securities for the three months ended March 31, 2018 and 2017. As of March 31, 2018, the Company did not own any non-agency collateralized mortgage obligations. 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) for which aggregate adjusted cost exceeded 10% of the consolidated shareholders’ equity at such respective dates. Securities with an amortized cost of $5.69 billion and $5.94 billion and a fair value of $5.50 billion and $5.84 billion at March 31, 2018 and December 31, 2017, respectively, were pledged to collateralize public deposits and for other purposes required or permitted by law.

Loans and Allowance for Credit

Loans and Allowance for Credit Losses	3 Months Ended
	Mar. 31, 2018
Receivables [Abstract]
Loans and Allowance for Credit Losses	5. LOANS AND ALLOWANCE FOR CREDIT LOSSES The loan portfolio consists of various types of loans and is categorized by major type as follows: March 31, 2018 December 31, 2017 (Dollars in thousands) Residential mortgage loans held for sale $ 34,551 $ 31,389 Commercial and industrial 1,524,385 1,479,910 Real estate: Construction, land development and other land loans 1,502,393 1,509,137 1-4 family residential (includes home equity) 2,688,012 2,708,471 Commercial real estate (includes multi-family residential) 3,330,860 3,315,627 Farmland 507,874 502,841 Agriculture 163,445 187,277 Consumer and other 259,896 286,121 Total loans held for investment 9,976,865 9,989,384 Total $ 10,011,416 $ 10,020,773 Concentrations of Credit. Most of the Company’s lending activity occurs within the states of Texas and Oklahoma. Commercial real estate loans, 1-4 family residential loans and construction, land development and other land loans make up 75.1% of the Company’s total loan portfolio at March 31, 2018. As of March 31, 2018 and December 31, 2017, there were no concentrations of loans related to any single industry in excess of 10% of total loans. Foreign Loans. The Company has U.S. dollar-denominated loans and commitments to borrowers in Mexico. The outstanding balance of these loans and the unfunded amounts available under these commitments were not significant at March 31, 2018 or December 31, 2017. Related Party Loans. As of March 31, 2018 and December 31, 2017, loans outstanding to directors, officers and their affiliates totaled $2.6 million and $2.7 million, respectively. All transactions between the Company and such related parties are conducted in the ordinary course of business and made on the same terms and conditions as similar transactions with unaffiliated persons. An analysis of activity with respect to these related party loans is as follows: As of and for the three months ended March 31, 2018 As of and for the year ended December (Dollars in thousands) Beginning balance on January 1 $ 2,694 $ 4,493 New loans — 175 Repayments and reclassified related loans (99 ) (1,974 ) Ending balance $ 2,595 $ 2,694 Nonperforming Assets and Nonaccrual and Past Due Loans. The Company has several procedures in place to assist it in maintaining the overall quality of its loan portfolio. The Company has established underwriting guidelines to be followed by its officers, including requiring appraisals on loans collateralized by real estate. The Company also monitors its delinquency levels for any negative or adverse trends. Nevertheless, the Company’s loan portfolio could become subject to increasing pressures from deteriorating borrower credit due to general economic conditions. The Company generally places a loan on nonaccrual status and ceases accruing interest when the payment of principal or interest is delinquent for 90 days, or earlier in some cases, unless the loan is in the process of collection and the underlying collateral fully supports the carrying value of the loan. With respect to potential problem loans, an evaluation of the borrower’s overall financial condition is made to determine the need, if any, for possible writedowns or appropriate additions to the allowance for credit losses. An aging analysis of past due loans, segregated by category of loan, is presented below: 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) Construction, land development and other land loans $ 3,859 $ — $ 3,859 $ 509 $ 1,498,025 $ 1,502,393 Agriculture and agriculture real estate (includes farmland) 1,132 — 1,132 128 670,059 671,319 1-4 family (includes home equity) (1) 3,741 75 3,816 5,053 2,713,694 2,722,563 Commercial real estate (includes multi-family residential) 2,595 — 2,595 3,380 3,324,885 3,330,860 Commercial and industrial 6,740 32 6,772 13,422 1,504,191 1,524,385 Consumer and other 540 — 540 80 259,276 259,896 Total $ 18,607 $ 107 $ 18,714 $ 22,572 $ 9,970,130 $ 10,011,416 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) Construction, land development and other land loans $ 8,046 $ 588 $ 8,634 $ 583 $ 1,499,920 $ 1,509,137 Agriculture and agriculture real estate (includes farmland) 562 — 562 132 689,424 690,118 1-4 family (includes home equity) (1) 7,550 416 7,966 5,117 2,726,777 2,739,860 Commercial real estate (includes multi-family residential) 6,995 — 6,995 3,932 3,304,700 3,315,627 Commercial and industrial 17,728 — 17,728 15,277 1,446,905 1,479,910 Consumer and other 605 — 605 223 285,293 286,121 Total $ 41,486 $ 1,004 $ 42,490 $ 25,264 $ 9,953,019 $ 10,020,773 (1) Includes $34.6 million and $31.4 million of residential mortgage loans held for sale at March 31, 2018 and December 31, 2017, respectively. The following table presents information regarding nonperforming assets as of the dates indicated: March 31, 2018 December 31, 2017 (Dollars in thousands) Nonaccrual loans (1) $ 22,572 $ 25,264 Accruing loans 90 or more days past due 107 1,004 Total nonperforming loans 22,679 26,268 Repossessed assets — 35 Other real estate 10,538 11,152 Total nonperforming assets $ 33,217 $ 37,455 Nonperforming assets to total loans and other real estate 0.33 % 0.37 % (1) Includes troubled debt restructurings of $50 thousand and $53 thousand as of March 31, 2018 and December 31, 2017, respectively. The Company had $33.2 million in nonperforming assets at March 31, 2018 compared with $37.5 million at December 31, 2017. Nonperforming assets were 0.33% of total loans and other real estate at March 31, 2018 compared with 0.37% of total loans and other real estate at December 31, 2017. These low nonperforming asset ratios are reflective of the Company’s conservative lending approach. If interest on nonaccrual loans had been accrued under the original loan terms, approximately $526 thousand and $1.1 million would have been recorded as income for the three months ended March 31, 2018 and 2017, respectively. Acquired Loans. Acquired loans were preliminarily recorded at fair value based on a discounted cash flow valuation methodology that considers, among other things, interest rates, projected default rates, loss given default, and recovery rates. During the valuation process, the Company identified Purchased Credit-Impaired (“PCI”) and Non-PCI loans in the acquired loan portfolios. Loans acquired with evidence of credit quality deterioration at acquisition for which it was probable that the Company would not be able to collect all contractual amounts due were accounted for as PCI. PCI loan identification considers the following factors: payment history and past due status, debt service coverage, loan grading, collateral values and other factors that may indicate deterioration of credit quality since origination. Non-PCI loan identification considers the following factors: account types, remaining terms, annual interest rates or coupons, current market rates, interest types, past delinquencies, timing of principal and interest payments, loan to value ratios, loss exposures and remaining balances. Accretion of purchased discounts on PCI loans will be based on estimated future cash flows, regardless of contractual maturities. Accretion of purchased discounts on Non-PCI loans will be recognized on a level-yield basis based on contractual maturity of individual loans. PCI Loans. The carrying amount of PCI loans included in the consolidated balance sheet and the related outstanding balance as of the dates indicated are presented in the table below. The outstanding balance represents the total amount owed as of March 31, 2018 and December 31, 2017. March 31, 2018 December 31, 2017 (Dollars in thousands) PCI loans: Outstanding balance $ 30,503 $ 36,199 Discount (10,386 ) (14,215 ) Recorded investment $ 20,117 $ 21,984 Changes in the accretable yield for acquired PCI loans for the three months ended March 31, 2018 and 2017 were as follows: Three Months Ended March 31, 2018 2017 (Dollars in thousands) Balance at beginning of period $ 8,121 $ 9,778 Additions — — Reclassifications from nonaccretable 250 968 Accretion (686 ) (1,483 ) Balance at March 31 $ 7,685 $ 9,263 Income recognition on PCI loans is subject to the Company’s ability to reasonably estimate both the timing and amount of future cash flows. PCI loans for which the Company is accruing interest income are not considered non-performing or impaired. The non-accretable difference represents contractual principal and interest the Company does not expect to collect. Non-PCI Loans. The carrying amount of Non-PCI loans included in the consolidated balance sheet and the related outstanding balance as of the dates indicated are presented in the table below. The outstanding balance represents the total amount owed as of March 31, 2018 and December 31, 2017, including accrued but unpaid interest. March 31, 2018 December 31, 2017 (Dollars in thousands) Non-PCI loans: Outstanding balance $ 680,656 $ 738,706 Discount (18,885 ) (20,533 ) Recorded investment $ 661,771 $ 718,173 Changes in the discount accretion for Non-PCI loans for the three months ended March 31, 2018 and 2017 were as follows: Three Months Ended March 31, 2018 2017 (Dollars in thousands) Balance at beginning of period $ 20,533 $ 35,401 Additions — — Accretion charge-offs (8 ) (2 ) Accretion (1,640 ) (3,270 ) Balance at March 31 $ 18,885 $ 32,129 Impaired Loans. Loans are considered impaired when, based on current information and events, it is probable the Company will be unable to collect all amounts due in accordance with the original contractual terms of the loan agreement, including scheduled principal and interest payments. Impairment is evaluated in total for smaller-balance loans of a similar nature and on an individual loan basis for other loans. If a loan is impaired, a specific valuation allowance is allocated, if necessary, so that the loan is reported net, at the present value of estimated future cash flows using the loan’s existing rate or at the fair value of collateral if repayment is expected solely from the collateral. Interest payments on impaired loans are typically applied to principal unless collectability of the principal amount is reasonably assured, in which case interest is recognized on a cash basis. Impaired loans, or portions thereof, are charged off when deemed uncollectible. Impaired loans are set forth in the following tables. No interest income was recognized on impaired loans subsequent to their classification as impaired. The average recorded investment presented in the tables below is reported on a year-to-date basis. March 31, 2018 Recorded Investment Unpaid Contractual Principal Balance Related Allowance Average Recorded Investment (Dollars in thousands) With no related allowance recorded: Construction, land development and other land loans $ 509 $ 525 $ — $ 546 Agriculture and agriculture real estate (includes farmland) 1 2 — 66 1-4 family (includes home equity) 4,138 4,696 — 4,029 Commercial real estate (includes multi-family residential) 3,164 3,720 — 2,693 Commercial and industrial 10,555 18,125 — 9,201 Consumer and other 80 127 — 151 Total 18,447 27,195 — 16,686 With an allowance recorded: Construction, land development and other land loans — — — — Agriculture and agriculture real estate (includes farmland) 127 174 15 64 1-4 family (includes home equity) 915 945 165 1,053 Commercial real estate (includes multi-family residential) — — — 743 Commercial and industrial 2,842 3,103 957 4,497 Consumer and other — — — — Total 3,884 4,222 1,137 6,357 Total: Construction, land development and other land loans 509 525 — 546 Agriculture and agriculture real estate (includes farmland) 128 176 15 130 1-4 family (includes home equity) 5,053 5,641 165 5,082 Commercial real estate (includes multi-family residential) 3,164 3,720 — 3,436 Commercial and industrial 13,397 21,228 957 13,698 Consumer and other 80 127 — 151 $ 22,331 $ 31,417 $ 1,137 $ 23,043 December 31, 2017 Recorded Investment Unpaid Contractual Principal Balance Related Allowance Average Recorded Investment (Dollars in thousands) With no related allowance recorded: Construction, land development and other land loans $ 583 $ 600 $ — $ 298 Agriculture and agriculture real estate (includes farmland) 132 178 — 70 1-4 family (includes home equity) 3,920 4,181 — 3,185 Commercial real estate (includes multi-family residential) 2,222 2,254 — 2,703 Commercial and industrial 7,846 10,460 — 8,386 Consumer and other 222 269 — 170 Total 14,925 17,942 — 14,812 With an allowance recorded: Construction, land development and other land loans — — — — Agriculture and agriculture real estate (includes farmland) — — — 77 1-4 family (includes home equity) 1,191 1,213 559 814 Commercial real estate (includes multi-family residential) 1,486 1,499 366 887 Commercial and industrial 6,152 6,373 2,654 9,740 Consumer and other — — — 2 Total 8,829 9,085 3,579 11,520 Total: Construction, land development and other land loans 583 600 — 298 Agriculture and agriculture real estate (includes farmland) 132 178 — 147 1-4 family (includes home equity) 5,111 5,394 559 3,999 Commercial real estate (includes multi-family residential) 3,708 3,753 366 3,590 Commercial and industrial 13,998 16,833 2,654 18,126 Consumer and other 222 269 — 172 $ 23,754 $ 27,027 $ 3,579 $ 26,332 Credit Quality Indicators. As part of the on-going monitoring of the credit quality of the Company’s loan portfolio and methodology for calculating the allowance for credit losses, management assigns and tracks loan grades to be used as credit quality indicators. The following is a general description of the loan grades used: Grade 1— Credits in this category have risk potential that is virtually nonexistent. These loans may be secured by insured certificates of deposit, insured savings accounts, U.S. Government securities and highly rated municipal bonds. Grade 2— Credits in this category are of the highest quality. These borrowers represent top rated companies and individuals with unquestionable financial standing with excellent global cash flow coverage, net worth, liquidity and collateral coverage. Grade 3— Credits in this category are not immune from risk but are well protected by the collateral and paying capacity of the borrower. These loans may exhibit a minor unfavorable credit factor, but the overall credit is sufficiently strong to minimize the possibility of loss. Grade 4— Credits in this category are considered to be of acceptable credit quality with moderately greater risk than Grade 3 and receiving closer monitoring. Loans in this category have sources of repayment that remain sufficient to preclude a larger than normal probability of default and secondary sources are likewise currently of sufficient quantity, quality, and liquidity to protect the Company against loss of principal and interest. These borrowers have specific risk factors, but the overall strength of the credit is acceptable based on other mitigating credit and/or collateral factors and can repay the debt in the normal course of business. Grade 5— Credits in this category constitute an undue and unwarranted credit risk; however, the factors do not rise to a level of substandard. These credits have potential weaknesses and/or declining trends that, if not corrected, could expose the Bank to risk at a future date. These loans are monitored on the Bank’s internally-generated watch list and evaluated on a quarterly basis. Grade 6— Credits in this category are considered “substandard” but “non-impaired” loans in accordance with regulatory guidelines. Loans in this category have well-defined weakness that, if not corrected, could make default of principal and interest possible. Loans in this category are still accruing interest and may be dependent upon secondary sources of repayment and/or collateral liquidation. Grade 7— Credits in this category are deemed “substandard” and “impaired” pursuant to regulatory guidelines. As such, the Bank has determined that it is probable that less than 100% of the contractual principal and interest will be collected. These loans are individually evaluated for a specific reserve and will typically have the accrual of interest stopped. Grade 8— Credits in this category include “doubtful” loans in accordance with regulatory guidance. Such loans are no longer accruing interest and factors indicate a loss is imminent. These loans are also deemed “impaired.” While a specific reserve may be in place while the loan and collateral is being evaluated, these loans are typically charged down to an amount the Bank estimates is collectible. Grade 9— Credits in this category are deemed a “loss” in accordance with regulatory guidelines and have been charged off or charged down. The Bank may continue collection efforts and may have partial recovery in the future. The following table presents risk grades and PCI loans by category of loan at March 31, 2018. Impaired loans include loans in risk grades 7, 8 and 9, as well as any PCI loan that has a specific reserve allocated to it. Construction, Land Development and Other Agriculture and Agriculture Real Estate (includes Farmland) 1-4 Family (includes Home (1) Commercial Real Estate (includes Multi-Family Commercial and Industrial Consumer and Other Total (Dollars in thousands) Grade 1 $ — $ 14,036 $ — $ — $ 51,860 $ 38,151 $ 104,047 Grade 2 1,799 3,989 24,159 15,054 9,471 49,868 104,340 Grade 3 1,427,119 578,643 2,621,931 2,909,404 1,154,938 158,257 8,850,292 Grade 4 62,489 65,513 58,380 347,668 195,050 8,703 737,803 Grade 5 2,565 7,286 5,395 26,990 67,763 2,900 112,899 Grade 6 7,103 1,344 3,212 15,840 30,151 1,937 59,587 Grade 7 509 128 4,987 3,164 10,367 80 19,235 Grade 8 — — 66 — 3,030 — 3,096 Grade 9 — — — — — — — PCI Loans (2) 809 380 4,433 12,740 1,755 — 20,117 Total $ 1,502,393 $ 671,319 $ 2,722,563 $ 3,330,860 $ 1,524,385 $ 259,896 $ 10,011,416 (1) Includes $34.6 million of residential mortgage loans held for sale at March 31, 2018. (2) Of the total PCI loans, $241 thousand were classified as substandard at March 31, 2018, with no specific reserves allocated to them. The following table presents risk grades and PCI loans by category of loan at December 31, 2017. Impaired loans include loans in risk grades 7, 8 and 9, as well as any PCI loan that has a specific reserve allocated to it. Construction, Land Development and Other Agriculture and Agriculture Real Estate (includes Farmland) 1-4 Family (includes Home (1) Commercial Real Estate (includes Multi-Family Commercial and Industrial Consumer and Other Total (Dollars in thousands) Grade 1 $ — $ 14,084 $ — $ — $ 50,174 $ 38,029 $ 102,287 Grade 2 1,848 4,190 28,053 18,953 20,561 52,210 125,815 Grade 3 1,419,648 594,082 2,632,788 2,955,774 1,084,580 180,494 8,867,366 Grade 4 78,117 68,019 61,146 272,848 209,279 10,226 699,635 Grade 5 788 7,964 3,558 34,811 58,655 3,200 108,976 Grade 6 7,284 1,266 4,640 16,415 39,611 1,740 70,956 Grade 7 583 132 4,681 3,708 13,755 222 23,081 Grade 8 — — 430 — 243 — 673 Grade 9 — — — — — — — PCI Loans (2) 869 381 4,564 13,118 3,052 — 21,984 Total $ 1,509,137 $ 690,118 $ 2,739,860 $ 3,315,627 $ 1,479,910 $ 286,121 $ 10,020,773 (1) Includes $31.4 million of residential mortgage loans held for sale at December 31, 2017. (2) Of the total PCI loans, $1.5 million were classified as substandard at December 31, 2017, with no specific reserves allocated to them. Allowance for Credit Losses. The allowance for credit losses is a valuation established through charges to earnings in the form of a provision for credit losses. Management has established an allowance for credit losses which it believes is adequate as of March 31, 2018 for estimated losses in the Company’s loan portfolio. The amount of the allowance for credit losses is affected by the following: (1) charge-offs of loans that occur when loans are deemed uncollectible and decrease the allowance, (2) recoveries on loans previously charged off that increase the allowance and (3) provisions for credit losses charged to earnings that increase the allowance. Based on an evaluation of the loan portfolio and consideration of the factors listed below, management presents a quarterly review of the allowance for credit losses to the Bank’s Board of Directors, indicating any change in the allowance since the last review and any recommendations as to adjustments in the allowance. Although management believes it uses the best information available to make determinations with respect to the allowance for credit losses, future adjustments may be necessary if economic conditions or the borrower’s performance differ from the assumptions used in making the initial determinations. The Company’s allowance for credit losses consists of two components: (1) a specific valuation allowance based on probable losses on specifically identified loans and (2) a general valuation allowance based on historical loan loss experience, general economic conditions and other qualitative risk factors both internal and external to the Company. In setting the specific valuation allowance, the Company follows a loan review program to evaluate the credit risk in the total loan portfolio and assigns risk grades to each loan. Through this loan review process, the Company maintains an internal list of impaired loans, which along with the delinquency list of loans, helps management assess the overall quality of the loan portfolio and the adequacy of the allowance for credit losses. All loans that have been identified as impaired are reviewed on a quarterly basis in order to determine whether a specific reserve is required. For certain impaired loans, the Company allocates a specific loan loss reserve primarily based on the value of the collateral securing the impaired loan in accordance with ASC Topic 310-10, “ Receivables. In connection with this review of the loan portfolio, the Company considers risk elements attributable to particular loan types or categories in assessing the quality of individual loans. Some of the risk elements include: • for 1-4 family residential mortgage loans, the borrower’s ability to repay the loan, including a consideration of the debt to income ratio and employment and income stability, the loan to value ratio, and the age, condition and marketability of collateral; • for commercial real estate loans and multifamily residential loans, the debt service coverage ratio (income from the property in excess of operating expenses compared to loan payment requirements), operating results of the owner in the case of owner-occupied properties, the loan to value ratio, the age and condition of the collateral and the volatility of income, property value and future operating results typical of properties of that type; • for construction, land development and other land loans, the perceived feasibility of the project including the ability to sell developed lots or improvements constructed for resale or the ability to lease property constructed for lease, the quality and nature of contracts for presale or prelease, if any, experience and ability of the developer and loan to value ratio; • for commercial and industrial loans, the operating results of the commercial, industrial or professional enterprise, the borrower’s business, professional and financial ability and expertise, the specific risks and volatility of income and operating results typical for businesses in that category and the value, nature and marketability of collateral; • for agriculture real estate loans, the experience and financial capability of the borrower, projected debt service coverage of the operations of the borrower and loan to value ratio; and • for non-real estate agriculture loans, the operating results, experience and financial capability of the borrower, historical and expected market conditions and the value, nature and marketability of collateral. In addition, for each category, the Company considers secondary sources of income and the financial strength and credit history of the borrower and any guarantors. In determining the amount of the general valuation allowance, management considers factors such as historical loan loss experience, concentration risk of specific loan types, the volume, growth and composition of the Company’s loan portfolio, current economic conditions that may affect the borrower’s ability to pay and the value of collateral, the evaluation of the Company’s loan portfolio through its internal loan review process, general economic conditions, other qualitative risk factors both internal and external to the Company and other relevant factors in accordance with ASC Topic 450, “ Contingencies. The following table details activity in the allowance for credit losses by category of loan for the three months ended March 31, 2018 and 2017. Allocation of a portion of the allowance to one category of loans does not preclude its availability to absorb losses in other categories. Construction, Land Development and Other Land Loans Agriculture and Agriculture Real Estate (includes Farmland) 1-4 Family (includes Home Equity) Commercial Real Estate (includes Multi-Family Residential) Commercial and Industrial Consumer and Other Total (Dollars in thousands) Allowance for credit losses: Three Months Ended Balance December 31, 2017 $ 14,815 $ 3,772 $ 14,490 $ 10,628 $ 38,810 $ 1,526 $ 84,041 Provision for credit losses (70 ) (529 ) (1,161 ) 727 9,546 487 9,000 Charge-offs (130 ) — (266 ) (503 ) (8,176 ) (1,010 ) (10,085 ) Recoveries 7 61 9 1 160 406 644 Net charge-offs (123 ) 61 (257 ) (502 ) (8,016 ) (604 ) (9,441 ) Balance March 31, 2018 $ 14,622 $ 3,304 $ 13,072 $ 10,853 $ 40,340 $ 1,409 $ 83,600 Allowance for credit losses: Three Months Ended Balance December 31, 2016 $ 14,984 $ 4,073 $ 16,571 $ 12,256 $ 35,836 $ 1,606 $ 85,326 Provision for credit losses (386 ) (554 ) (895 ) (1,148 ) 5,341 317 2,675 Charge-offs — — (13 ) (133 ) (3,638 ) (824 ) (4,608 ) Recoveries 65 65 108 — 143 321 702 Net charge-offs 65 65 95 (133 ) (3,495 ) (503 ) (3,906 ) Balance March 31, 2017 $ 14,663 $ 3,584 $ 15,771 $ 10,975 $ 37,682 $ 1,420 $ 84,095 The following table details the amount of the allowance for credit losses allocated to each category of loan as of March 31, 2018, December 31, 2017 and March 31, 2017, on the basis of the impairment methodology used by the Company. Construction, Land Development and Other Land Loans Agriculture and Agriculture Real Estate (includes Farmland) 1-4 Family (includes Home Equity) Commercial Real Estate (includes Multi-Family Residential) Commercial and Industrial Consumer and Other Total (Dollars in thousands) Allowance for credit losses related March 31, 2018 Individually evaluated for impairment $ — $ 15 $ 165 $ — $ 957 $ — $ 1,137 Collectively evaluated for impairment 14,622 3,289 12,907 10,853 39,383 1,409 82,463 PCI loans — — — — — — — Total allowance for credit losses $ 14,622 $ 3,304 $ 13,072 $ 10,853 $ 40,340 $ 1,409 $ 83,600 December 31, 2017 Individually evaluated for impairment $ — $ — $ 559 $ 366 $ 2,654 $ — $ 3,579 Collectively evaluated for impairment 14,815 3,772 13,931 10,262 36,156 1,526 80,462 PCI loans — — — — — — — Total allowance for credit losses $ 14,815 $ 3,772 $ 14,490 $ 10,628 $ 38,810 $ 1,526 $ 84,041 March 31, 2017 Individually evaluated for impairment $ — $ 10 $ 113 $ — $ 1,203 $ 1 $ 1,327 Collectively evaluated for impairment 14,663 3,574 15,658 10,975 36,479 1,419 82,768 PCI loans — — — — — — — Total allowance for credit losses $ 14,663 $ 3,584 $ 15,771 $ 10,975 $ 37,682 $ 1,420 $ 84,095 The following table details the recorded investment in loans as of March 31, 2018, December 31, 2017 and March 31, 2017, excluding $34.6 million, $31.4 million and $21.9 million, respectively, of residential mortgage loans held for sale, related to each balance in the allowance for credit losses by category of loan. Construction, Land Development and Other Land Loans Agriculture and Agriculture Real Estate (includes Farmland) 1-4 Family (includes Home Equity) Commercial Real Estate (includes Multi-Family Residential) Commercial and Industrial Consumer and Other Total (Dollars in thousands) Recorded investment in March 31, 2018 Individually evaluated for impairment $ 509 $ 128 $ 5,053 $ 3,164 $ 13,397 $ 80 $ 22,331 Collectively evaluated for impairment 1,501,075 670,811 2,678,526 3,314,956 1,509,233 259,816 9,934,417 PCI loans 809 380 4,433 12,740 1,755 — 20,117 Total loans evaluated for impairment $ 1,502,393 $ 671,319 $ 2,688,012 $ 3,330,860 $ 1,524,385 $ 259,896 $ 9,976,865 December 31, 2017 Individually evaluated for impairment $ 583 $ 132 $ 5,111 $ 3,708 $ 13,998 $ 222 $ 23,754 Collectively evaluated for impairment 1,507,685 689,605 2,698,796 3,298,801 1,462,860 285,899 9,943,646 PCI loans 869 381 4,564 13,118 3,052 — 21,984 Total loans evaluated for impairment $ 1,509,137 $ 690,118 $ 2,708,471 $ 3,315,627 $ 1,479,910 $ 286,121 $ 9,989,384 March 31, 2017 Individually evaluated for impairment $ 231 $ 534 $ 3,168 $ 2,043 $ 16,666 $ 139 $ 22,781 Collectively evaluated for impairment 1,325,082 661,875 2,675,929 3,208,810 1,534,675 262,162 9,668,533 PCI loans 1,372 388 4,838 16,125 3,320 — 26,043 Total loans evaluated for impairment $ 1,326,685 $ 662,797 $ 2,683,935 $ 3,226,978 $ 1,554,661 $ 262,301 $ 9,717,357 Troubled Debt Restructurings. The restructuring of a loan is considered a “troubled debt restructuring” if both (1) the borrower is experiencing financial difficulties and (2) the creditor has granted a concession. Concessions may include interest rate reductions or below market interest rates, principal forgiveness, restructuring amortization schedules and other actions intended to minimize potential losses. Under ASC topic 310-40 “ the Company evaluates all loan modifications to identify whether the restructuring constitutes a troubled debt restructuring. As of March 31, 2018 and 2017, the Company had $50 thousand and $8.7 million, respectively, in outstanding troubled debt restructurings. The following table presents information regarding the recorded investment of loans modified as troubled debt restructurings during the three months ended March 31, 2018 and 2017: Three Months Ended March 31, 2018 2017 Number of Loans Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Number of Loans Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment (Dollars in thousands) Troubled Debt Restructurings Construction, land development and other land loans — $ — $ — — $ — $ — Agriculture and agriculture real estate (includes farmland) — — — — — — 1-4 Family (includes home equity) — — — — — — Commercial real estate (includes multi-family residential) — — — — — — Commercial and industrial — — — 3 8,656 8,650 Consumer and other — — — — — — Total — $ — $ — 3 $ 8,656 $ 8,650 For the three months ended March 31, 2018, the Company did not add loans as new troubled debt restructurings. For the three months ended March 31, 2017, the Company added three loans totaling $8.7 million as new troubled debt restructurings, of which $8.7 million was outstanding at March 31, 2017. As of March 31, 2018, there have been no defaults on any loans that were modified as troubled debt restructurings during the preceding twelve months. Default is determined at 90 or more days past due. There were no charge-offs related to restructured loans recognized during the three months ended March 31, 2018. During 2017, the Company recognized charge-offs totaling $4.3 million related to defaults on loans restructured during the first quarter of 2017. The modifications generally related to extending the amortization periods of the loans, which includes loans modified during bankruptcy. The Company did not grant principal reductions on any restructured loans at the time of modification. These modifications did not have a material impact on the Company’s determination of the allowance for credit losses.

Fair Value

Fair Value	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value	6. FAIR VALUE The Company uses fair value measurements to record fair value adjustments to certain assets and to determine fair value disclosures. Fair values represent the estimated price that would be received from selling an asset or paid to transfer a liability, otherwise known as an “exit price.” Securities available for sale are recorded at fair value on a recurring basis. Additionally, from time to time, the Company may be required to record other assets at fair value on a nonrecurring basis such as certain loans including residential mortgage loans held for sale, goodwill and other intangible assets and other real estate owned. These nonrecurring fair value adjustments typically involve application of lower-of-cost-or-market accounting or write downs of individual assets. ASC Topic 820 “ Fair Value Measurements and Disclosures Fair Value Hierarchy 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 in active markets for identical assets or liabilities. • Level 2—Other significant observable inputs (including quoted prices in active markets for similar assets or liabilities) or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The fair value of an asset or liability is the price that would be received to sell that asset or paid to transfer that liability in an orderly transaction occurring in the principal market (or most advantageous market in the absence of a principal market) for such asset or liability. In estimating fair value, the Company utilizes valuation techniques that are consistent with the market approach, the income approach and/or the cost approach. Such valuation techniques are consistently applied. Inputs to valuation techniques include the assumptions that market participants would use in pricing an asset or liability. The fair value disclosures below represent the Company’s estimates based on relevant market information and information about the financial instruments. Fair value estimates are based on judgments regarding current economic conditions, risk characteristics of the various instruments and other factors. These estimates are subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision. Changes in the above methodologies and assumptions could significantly affect the estimates. The following tables present fair values for assets and liabilities measured at fair value on a recurring basis: As of March 31, 2018 Level 1 Level 2 Level 3 Total (Dollars in thousands) Assets: Available for sale securities: States and political subdivisions $ — $ 1,672 $ — $ 1,672 Collateralized mortgage obligations — 96,261 — 96,261 Mortgage-backed securities — 97,287 — 97,287 Other securities 12,269 — — 12,269 Total $ 12,269 $ 195,220 $ — $ 207,489 As of December 31, 2017 Level 1 Level 2 Level 3 Total (Dollars in thousands) Assets: Available for sale securities: States and political subdivisions $ — $ 1,820 $ — $ 1,820 Collateralized mortgage obligations — 100,061 — 100,061 Mortgage-backed securities — 103,489 — 103,489 Other securities 12,500 — — 12,500 Total $ 12,500 $ 205,370 $ — $ 217,870 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 (for example, when there is evidence of impairment). These instruments include other real estate owned, repossessed assets, held to maturity debt securities, loans held for sale and impaired loans, which are included as loans held for investment. For the three months ended March 31, 2018, the Company had additions to other real estate owned of $47 thousand, all of which was still outstanding as of March 31, 2018. For the three months ended March 31, 2018, the Company had additions to impaired loans of $7.0 million, all of which was still outstanding as of March 31, 2018. The remaining financial assets and liabilities measured at fair value on a non-recurring basis that were recorded in 2018 and remained outstanding at March 31, 2018 were not significant. The following tables present carrying and fair value information of financial instruments as of the dates indicated: As of March 31, 2018 Carrying Estimated Fair Value Amount Level 1 Level 2 Level 3 Total Assets (Dollars in thousands) Cash and due from banks $ 243,514 $ 243,514 $ — $ — $ 243,514 Federal funds sold 469 469 — — 469 Held to maturity securities 9,502,765 — 9,239,443 — 9,239,443 Loans held for sale 34,551 — 34,551 — 34,551 Loans held for investment, net of allowance 9,893,265 — — 9,869,788 9,869,788 Other real estate owned 10,538 — 10,538 — 10,538 Liabilities Deposits: Noninterest-bearing $ 5,707,994 $ — $ 5,707,994 $ — $ 5,707,994 Interest-bearing 11,624,885 — 11,594,367 — 11,594,367 Other borrowings 820,079 — 820,184 — 820,184 Securities sold under repurchase agreements 339,576 — 339,532 — 339,532 As of December 31, 2017 Carrying Estimated Fair Value Amount Level 1 Level 2 Level 3 Total Assets (Dollars in thousands) Cash and due from banks $ 391,616 $ 391,616 $ — $ — $ 391,616 Federal funds sold 697 697 — — 697 Held to maturity securities 9,454,246 — 9,323,482 — 9,323,482 Loans held for sale 31,389 — 31,389 — 31,389 Loans held for investment, net of allowance 9,905,343 — — 9,923,556 9,923,556 Other real estate owned 11,152 — 11,152 — 11,152 Liabilities Deposits: Noninterest-bearing $ 5,623,322 $ — $ 5,623,322 $ — $ 5,623,322 Interest-bearing 12,198,138 — 12,173,164 — 12,173,164 Other borrowings 505,223 — 505,390 — 505,390 Securities sold under repurchase agreements 324,154 — 324,118 — 324,118 The following is a description of the fair value estimates, methods and assumptions that are used by the Company in estimating the fair values of financial instruments. Loans held for sale — Loans held for sale are carried at the lower of cost or estimated fair value. Fair value for consumer mortgages held for sale is based on commitments on hand from investors or prevailing market prices. As such, the Company classifies loans subjected to nonrecurring fair value adjustments as Level 2. Loans held for investment — The Company does not record loans at fair value on a recurring basis. As such, valuation techniques discussed herein for loans are primarily for estimating fair value disclosures. The Company refined the calculation to estimate fair value for loans held for investment to be in accordance with ASU 2016-01. The refined discounted cash flow calculation to determine fair value considers internal and market-based information such as prepayment risk, cost of funds and liquidity. From time to time, the Company records nonrecurring fair value adjustments to impaired loans to reflect (1) partial write downs that are based on the observable market price or current appraised value of the collateral, or (2) the full charge-off of the loan carrying value. Where appraisals are not available, estimated cash flows are discounted using a rate commensurate with the credit risk associated with those cash flows. Assumptions regarding credit risk, cash flows and discount rates are judgmentally determined using available market information and specific borrower information. The Company classifies the estimated fair value of loans held for investment as Level 3. Other real estate owned — Other real estate owned is primarily foreclosed properties securing residential loans and commercial real estate. Foreclosed assets are adjusted to fair value less estimated costs to sell upon transfer of the loans to other real estate owned. Subsequently, these assets are carried at the lower of carrying value or fair value less estimated costs to sell. Other real estate carried at fair value based on an observable market price or a current appraised value is classified by the Company as Level 2. When management determines that the fair value of other real estate requires additional adjustments, either as a result of a non-current appraisal or when there is no observable market price, the Company classifies the other real estate as Level 3. The fair value estimates presented herein are based on pertinent information available to management at March 31, 2018. Although management is not aware of any factors that would significantly affect the estimated fair value amounts, such amounts have not been comprehensively revalued for purposes of these financial statements since those dates and, therefore, current estimates of fair value may differ significantly from the amounts presented herein.

Goodwill and Core Deposit Intan

Goodwill and Core Deposit Intangibles	3 Months Ended
	Mar. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Core Deposit Intangibles	7. GOODWILL AND CORE DEPOSIT INTANGIBLES Changes in the carrying amount of the Company’s goodwill and core deposit intangibles for the three months ended March 31, 2018 and the year ended December 31, 2017 were as follows: Goodwill Core Deposit Intangibles (Dollars in thousands) Balance as of December 31, 2016 $ 1,900,845 $ 45,784 Less: Amortization — (6,942 ) Balance as of December 31, 2017 1,900,845 38,842 Less: Amortization — (1,568 ) Balance as of March 31, 2018 $ 1,900,845 $ 37,274 Goodwill is recorded on the acquisition date of each entity. The Company may record subsequent adjustments to goodwill for amounts undeterminable at acquisition date, such as deferred taxes and real estate valuations, and therefore the goodwill amounts may change accordingly. The Company initially records the total premium paid on acquisitions as goodwill. After finalizing the valuation, core deposit intangibles are identified and reclassified from goodwill to core deposit intangibles on the balance sheet. This reclassification has no effect on total assets, liabilities, shareholders’ equity, net income or cash flows. Management performs an evaluation annually, and more frequently if a triggering event occurs, of whether any impairment of the goodwill and core deposit intangibles has occurred. If any such impairment is determined, a write-down is recorded. As of March 31, 2018, there was no impairment recorded on goodwill and core deposit intangibles. The measurement period for the Company to determine the fair value of acquired identifiable assets and assumed liabilities will be at the end of the earlier of (1) twelve months from the date of acquisition or (2) as soon as the Company receives the information it was seeking about facts and circumstances that existed as of the date of acquisition. Core deposit intangibles are being amortized on a non-pro rata basis over their estimated lives, which the Company believes is between 10 and 15 years. Amortization expense related to intangible assets totaled $1.6 million and $1.9 million for the three months ended March 31, 2018 and 2017, respectively. The estimated aggregate future amortization expense for core deposit intangibles remaining as of March 31, 2018 is as follows (dollars in thousands): Remaining 2018 $ 4,391 2019 5,051 2020 4,483 2021 4,022 2022 3,664 Thereafter 15,663 Total $ 37,274

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	8. STOCK–BASED COMPENSATION At March 31, 2018, the Company had two stock-based employee compensation plans with awards outstanding. One of these plans has expired and therefore no additional awards may be issued under that plan. During 2004, Bancshares’ Board of Directors established the Prosperity Bancshares, Inc. 2004 Stock Incentive Plan (the “2004 Plan”), which was approved by Bancshares’ shareholders and authorized the issuance of up to 1,250,000 shares of common stock upon the exercise of options granted under the 2004 Plan or upon the grant or exercise, as the case may be, of other awards granted under the 2004 Plan. The 2004 Plan provided for grants of incentive and nonqualified stock options to employees and nonqualified stock options to directors who are not employees. The 2004 Plan also provided for grants of shares of restricted stock, stock appreciation rights, phantom stock awards and performance awards on substantially similar terms. The 2004 Plan has expired and therefore no additional shares may be issued under the 2004 Plan. During 2012, Bancshares’ Board of Directors established the Prosperity Bancshares, Inc. 2012 Stock Incentive Plan (the “2012 Plan”), which was approved by Bancshares’ shareholders and authorized the issuance of up to 1,250,000 shares of common stock upon the exercise of options granted under the 2012 Plan or pursuant to the grant or exercise, as the case may be, of other awards granted under the 2012 Plan, including restricted stock, stock appreciation rights, phantom stock awards and performance awards. A total of 692,109 shares have been granted under the 2012 Plan as of March 31, 2018. As of March 31, 2018 and 2017, all stock options have been exercised and there are no more options outstanding. The Company received $148 thousand from the exercise of all remaining stock options during the three-month period ended March 31, 2017. There was no tax benefit realized from option exercises of the stock-based payment arrangements during the three-month periods ended March 31, 2017. Stock-based compensation expense related to restricted stock was $2.6 million and $1.7 million during the three months ended March 31, 2018 and 2017, respectively. As of March 31, 2018, there was $26.7 million of total unrecognized compensation expense related to stock-based compensation arrangements. That cost is expected to be recognized over a weighted average period of 2.04 years.

Contractual Obligations and Off

Contractual Obligations and Off-Balance Sheet Items	3 Months Ended
	Mar. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Contractual Obligations and Off-Balance Sheet Items	9. CONTRACTUAL OBLIGATIONS AND OFF-BALANCE SHEET ITEMS Contractual Obligations The following table summarizes the Company’s contractual obligations and other commitments to make future payments as of March 31, 2018 (other than deposit obligations and securities sold under repurchase agreements). The Company’s future cash payments associated with its contractual obligations pursuant to its Federal Home Loan Bank (“FHLB”) notes payable and operating leases as of March 31, 2018 are summarized below. Payments for FHLB notes payable include interest of $290 thousand that will be paid over the future periods. Payments related to leases are based on actual payments specified in underlying contracts. 1 year or less More than 1 year but less than 3 years 3 years or more but less than 5 years 5 years or more Total (Dollars in thousands) Federal Home Loan Bank notes payable $ 819,207 $ 901 $ 125 $ 136 $ 820,369 Operating leases 4,895 7,290 3,736 4,676 20,597 Total $ 824,102 $ 8,191 $ 3,861 $ 4,812 $ 840,966 Off-Balance Sheet Items In the normal course of business, the Company enters into various transactions that, in accordance with GAAP, are not included in its 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’s commitments associated with outstanding standby letters of credit and commitments to extend credit expiring by period as of March 31, 2018 are summarized below. Since commitments associated with letters of credit and commitments to extend credit may expire unused, the amounts shown do not necessarily reflect the actual future cash funding requirements. 1 year or less More than 1 year but less than 3 years 3 years or more but less than 5 years 5 years or more Total (Dollars in thousands) Standby letters of credit $ 72,593 $ 5,389 $ 1,687 $ — $ 79,669 Commitments to extend credit 1,019,610 359,381 181,434 1,022,606 2,583,031 Total $ 1,092,203 $ 364,770 $ 183,121 $ 1,022,606 $ 2,662,700

Other Comprehensive Income (Los

Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Other Comprehensive Income (Loss)	10. OTHER COMPREHENSIVE INCOME (LOSS) The tax effects allocated to each component of other comprehensive income (loss) were as follows: Three Months Ended March 31, 2018 2017 Before Tax Amount Tax Effect Net of Tax Amount Before Tax Amount Tax Effect Net of Tax Amount (Dollars in thousands) Other comprehensive income: Securities available for sale: Change in unrealized gain during period $ 200 $ (42 ) $ 158 $ 29 $ (10 ) $ 19 Total securities available for sale 200 (42 ) 158 29 (10 ) 19 Total other comprehensive income $ 200 $ (42 ) $ 158 $ 29 $ (10 ) $ 19 Activity in accumulated other comprehensive income associated with securities available for sale, net of tax, was as follows: Securities Available for Sale Accumulated Other Comprehensive Income (Dollars in thousands) Balance at January 1, 2018 $ (113 ) $ (113 ) Other comprehensive income 158 158 Balance at March 31, 2018 $ 45 $ 45 Balance at January 1, 2017 $ 1,411 $ 1,411 Other comprehensive income 19 19 Balance at March 31, 2017 $ 1,430 $ 1,430

New Accounting Standards (Polic

New Accounting Standards (Policies)	3 Months Ended
	Mar. 31, 2018
New Accounting Pronouncements And Changes In Accounting Principles [Abstract]
Accounting Standards Updates (''ASU'')	Accounting Standards Updates (“ASU”) ASU 2018-02, “Income Statement-Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” The amendments of ASU 2018-02 allow a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act. ASU 2018-02 is effective for all entities beginning January 1, 2019 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).” ASU 2017-08 shortens the amortization period for certain callable debt securities held at a premium. Specifically, the amendments require the premium to be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. ASU 2017-08 will be effective for the Company on January 1, 2019 on a modified retrospective basis with a cumulative-effect adjustment as of the beginning of the period of adoption and is not expected to have a significant impact on the Company’s financial statements. ASU 2016-13, “Financial Instruments – Credit Losses (Topic 326)—Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 requires a financial asset (or a group of financial assets) measured at amortized cost basis to be presented at the net amount expected to be collected. The measurement of expected credit losses is based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. An entity must use judgment in determining the relevant information and estimation methods that are appropriate in its circumstances. Additionally, available for sale debt securities may realize value either through collection of contractual cash flows or through sale of the security at fair value. Therefore, the amendments limit the amount of the allowance for credit losses to the difference between amortized cost and fair value. ASU 2016-13 will be effective for the Company as of January 1, 2020. The Company is currently evaluating the potential impact of ASU 2016-13 on the Company’s financial statements. ASU 2016-02, "Leases (Topic 842)." ASU 2016-02 requires that lessees and lessors recognize lease assets and lease liabilities on the balance sheet and disclose key information about leasing arrangements. ASU 2016-02 is effective for public companies for annual periods beginning January 1, 2019, including interim periods within those fiscal years. The Company is currently evaluating the potential impact of ASU 2016-02 on the Company’s financial statements. ASU 2016-01, “Financial Instruments—Overall (Subtopic 825-10)—Recognition and Measurement of Financial Assets and Financial Liabilities.” ASU 2016-01 addresses certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. ASU 2016-01 1) requires equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income; 2) simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; 3) eliminates the requirement to disclose the fair value of financial instruments measured at amortized cost for entities that are not public business entities; 4) eliminates the requirement for public business entities to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet; 5) requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; 6) requires an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments; 7) requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (that is, securities or loans and receivables) on the balance sheet or the accompanying notes to the financial statements; and 8) clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity’s other deferred tax assets. The amendments in this update affect all entities that hold financial assets or owe financial liabilities. ASU 2016-01 became effective for the Company on January 1, 2018, and did not have a material financial impact on the Company’s financial statements. 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. In addition, the FASB has issued targeted updates to clarify specific implementation issues of ASU 2014-09. These updates include ASU 2016-08 - ASU 2016-10 - ASU 2016-12 - and ASU 2016-20 - s. These amendments do not change the core principles in ASU 2014-09. The Company’s primary sources of revenue are comprised of net interest income on financial assets and liabilities, which are not within the scope of ASU 2014-09. The Company completed its overall assessment of revenue streams and review of related contracts potentially affected by the ASU. Based on this assessment, the Company concluded the ASU did not significantly change the method in which the Company currently recognizes revenue. ASU 2014-09 became effective for the Company on January 1, 2018 and did not have a material financial impact on the Company’s financial statements. The following provides further detail on other revenue streams within noninterest income that are within the scope of this update. Nonsufficient Funds (NSF) Fees – NSF fees are generated on a transactional basis from nonsufficient funds. Revenue is recognized once the performance obligation is satisfied. Credit card, debit card and ATM card income – Credit card and debit card income is primarily comprised of interchange fees earned on a transactional basis through card payment networks. ATM card income is generated when the Company’s card holders use foreign ATMs or when non-customers utilize the Company’s ATMs. Revenue is recognized after the performance obligation is satisfied generally after the transaction is completed. Service Charges on Deposit Accounts – Services charges on deposit accounts consist of account maintenance or transaction-based fees. The Company’s performance obligation is satisfied over a period of time for account maintenance and at the time of service for transaction-based fees. Revenue is recognized after the performance obligation is satisfied. Trust Income – Trust income represents monthly income from trust and estate administration, investment management services, and employee benefits services. The Company’s performance obligation is generally performed over a period of time and varies by the type of trust services being provided to the customer. Revenue is recognized after the performance obligation is satisfied. Brokerage Income – Brokerage income represents fees and commissions from asset management services and transaction processing. The Company’s performance obligation is generally performed over a period of time for asset management services and at a point in time for transaction processing. Revenue is recognized after the performance obligation is satisfied.

Income Per Common Share (Tables

Income Per Common Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table illustrates the computation of basic and diluted earnings per share: Three Months Ended March 31, 2018 2017 Amount Per Share Amount Amount Per Share Amount (Amounts in thousands, except per share data) Net income $ 74,361 $ 68,565 Basic: Weighted average shares outstanding 69,768 $ 1.07 69,480 $ 0.99 Diluted: Add incremental shares for: Effect of dilutive securities - options — 2 Total 69,768 $ 1.07 69,482 $ 0.99

Securities (Tables)

Securities (Tables)	3 Months Ended
	Mar. 31, 2018
Investments Debt And Equity Securities [Abstract]
Schedule of Amortized Cost and Fair Value of Investment 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 States and political subdivisions $ 1,668 $ 4 $ — $ 1,672 Collateralized mortgage obligations 95,544 770 (53 ) 96,261 Mortgage-backed securities 97,632 986 (1,331 ) 97,287 Other securities 12,588 — (319 ) 12,269 Total $ 207,432 $ 1,760 $ (1,703 ) $ 207,489 Held to Maturity U.S. Treasury securities and obligations of U.S. Government agencies $ 32,289 $ 43 $ (39 ) $ 32,293 States and political subdivisions 290,040 4,058 (538 ) 293,560 Collateralized mortgage obligations 615 2 (4 ) 613 Mortgage-backed securities 9,179,821 6,063 (272,907 ) 8,912,977 Total $ 9,502,765 $ 10,166 $ (273,488 ) $ 9,239,443 December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (Dollars in thousands) Available for Sale States and political subdivisions $ 1,817 $ 3 $ — $ 1,820 Collateralized mortgage obligations 99,996 122 (57 ) 100,061 Mortgage-backed securities 103,612 1,204 (1,327 ) 103,489 Other securities 12,588 13 (101 ) 12,500 Total $ 218,013 $ 1,342 $ (1,485 ) $ 217,870 Held to Maturity U.S. Treasury securities and obligations of U.S. Government agencies $ 32,235 $ 150 $ (5 ) $ 32,380 States and political subdivisions 328,666 4,263 (807 ) 332,122 Collateralized mortgage obligations 653 2 (5 ) 650 Mortgage-backed securities 9,092,692 9,382 (143,744 ) 8,958,330 Total $ 9,454,246 $ 13,797 $ (144,561 ) $ 9,323,482
Securities in Continuous Loss Position	Securities with unrealized losses, segregated by length of time, that have been in a continuous loss position were 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 Collateralized mortgage obligations $ 3,479 $ (27 ) $ 2,417 $ (26 ) $ 5,896 $ (53 ) Mortgage-backed securities 40,470 (1,328 ) 1,926 (3 ) 42,396 (1,331 ) Other securities 12,269 (319 ) — — 12,269 (319 ) Total $ 56,218 $ (1,674 ) $ 4,343 $ (29 ) $ 60,561 $ (1,703 ) Held to Maturity U.S. Treasury securities and obligations of U.S. Government agencies $ 25,397 $ (39 ) $ — $ — $ 25,397 $ (39 ) States and political subdivisions 86,764 (513 ) 2,881 (25 ) 89,645 (538 ) Collateralized mortgage obligations 354 (4 ) — — 354 (4 ) Mortgage-backed securities 4,802,646 (106,841 ) 3,669,817 (166,066 ) 8,472,463 (272,907 ) Total $ 4,915,161 $ (107,397 ) $ 3,672,698 $ (166,091 ) $ 8,587,859 $ (273,488 ) 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 Collateralized mortgage obligations $ 5,753 $ (13 ) $ 2,544 $ (44 ) $ 8,297 $ (57 ) Mortgage-backed securities 42,289 (1,323 ) 2,054 (4 ) 44,343 (1,327 ) Other securities 1,636 (101 ) — — 1,636 (101 ) Total $ 49,678 $ (1,437 ) $ 4,598 $ (48 ) $ 54,276 $ (1,485 ) Held to Maturity U.S. Treasury securities and obligations of U.S. Government agencies $ 4,934 $ (5 ) $ — $ — $ 4,934 $ (5 ) States and political subdivisions 160,392 (773 ) 3,686 (34 ) 164,078 (807 ) Collateralized mortgage obligations 373 (2 ) 100 (3 ) 473 (5 ) Mortgage-backed securities 3,940,075 (34,159 ) 3,883,266 (109,585 ) 7,823,341 (143,744 ) Total $ 4,105,774 $ (34,939 ) $ 3,887,052 $ (109,622 ) $ 7,992,826 $ (144,561 )
Investment Securities by Contractual Maturity	The amortized cost and fair value of investment securities at March 31, 2018, by contractual maturity, are shown below. Actual maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations at any time with or without call or prepayment penalties. Held to Maturity Available for Sale Amortized Cost Fair Value Amortized Cost Fair Value (Dollars in thousands) Due in one year or less $ 37,102 $ 37,237 $ 13,098 $ 12,779 Due after one year through five years 161,835 162,424 1,158 1,162 Due after five years through ten years 113,051 115,623 — — Due after ten years 10,341 10,569 — — Subtotal 322,329 325,853 14,256 13,941 Mortgage-backed securities and collateralized mortgage obligations 9,180,436 8,913,590 193,176 193,548 Total $ 9,502,765 $ 9,239,443 $ 207,432 $ 207,489

Loans and Allowance for Credi22

Loans and Allowance for Credit Losses (Tables)	3 Months Ended
	Mar. 31, 2018
Receivables [Abstract]
Types of Loans in Loan Portfolio	The loan portfolio consists of various types of loans and is categorized by major type as follows: March 31, 2018 December 31, 2017 (Dollars in thousands) Residential mortgage loans held for sale $ 34,551 $ 31,389 Commercial and industrial 1,524,385 1,479,910 Real estate: Construction, land development and other land loans 1,502,393 1,509,137 1-4 family residential (includes home equity) 2,688,012 2,708,471 Commercial real estate (includes multi-family residential) 3,330,860 3,315,627 Farmland 507,874 502,841 Agriculture 163,445 187,277 Consumer and other 259,896 286,121 Total loans held for investment 9,976,865 9,989,384 Total $ 10,011,416 $ 10,020,773
Related Party Loans	An analysis of activity with respect to these related party loans is as follows: As of and for the three months ended March 31, 2018 As of and for the year ended December (Dollars in thousands) Beginning balance on January 1 $ 2,694 $ 4,493 New loans — 175 Repayments and reclassified related loans (99 ) (1,974 ) Ending balance $ 2,595 $ 2,694
Aging Analysis of Past Due Loans	An aging analysis of past due loans, segregated by category of loan, is presented below: 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) Construction, land development and other land loans $ 3,859 $ — $ 3,859 $ 509 $ 1,498,025 $ 1,502,393 Agriculture and agriculture real estate (includes farmland) 1,132 — 1,132 128 670,059 671,319 1-4 family (includes home equity) (1) 3,741 75 3,816 5,053 2,713,694 2,722,563 Commercial real estate (includes multi-family residential) 2,595 — 2,595 3,380 3,324,885 3,330,860 Commercial and industrial 6,740 32 6,772 13,422 1,504,191 1,524,385 Consumer and other 540 — 540 80 259,276 259,896 Total $ 18,607 $ 107 $ 18,714 $ 22,572 $ 9,970,130 $ 10,011,416 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) Construction, land development and other land loans $ 8,046 $ 588 $ 8,634 $ 583 $ 1,499,920 $ 1,509,137 Agriculture and agriculture real estate (includes farmland) 562 — 562 132 689,424 690,118 1-4 family (includes home equity) (1) 7,550 416 7,966 5,117 2,726,777 2,739,860 Commercial real estate (includes multi-family residential) 6,995 — 6,995 3,932 3,304,700 3,315,627 Commercial and industrial 17,728 — 17,728 15,277 1,446,905 1,479,910 Consumer and other 605 — 605 223 285,293 286,121 Total $ 41,486 $ 1,004 $ 42,490 $ 25,264 $ 9,953,019 $ 10,020,773 (1) Includes $34.6 million and $31.4 million of residential mortgage loans held for sale at March 31, 2018 and December 31, 2017, respectively.
Non-performing Assets	The following table presents information regarding nonperforming assets as of the dates indicated: March 31, 2018 December 31, 2017 (Dollars in thousands) Nonaccrual loans (1) $ 22,572 $ 25,264 Accruing loans 90 or more days past due 107 1,004 Total nonperforming loans 22,679 26,268 Repossessed assets — 35 Other real estate 10,538 11,152 Total nonperforming assets $ 33,217 $ 37,455 Nonperforming assets to total loans and other real estate 0.33 % 0.37 % (1) Includes troubled debt restructurings of $50 thousand and $53 thousand as of March 31, 2018 and December 31, 2017, respectively.
Carrying Amount of PCI Loans and Related Outstanding Balance	The carrying amount of PCI loans included in the consolidated balance sheet and the related outstanding balance as of the dates indicated are presented in the table below. The outstanding balance represents the total amount owed as of March 31, 2018 and December 31, 2017. March 31, 2018 December 31, 2017 (Dollars in thousands) PCI loans: Outstanding balance $ 30,503 $ 36,199 Discount (10,386 ) (14,215 ) Recorded investment $ 20,117 $ 21,984
Changes in Accretable Yield for Acquired PCI Loans	Changes in the accretable yield for acquired PCI loans for the three months ended March 31, 2018 and 2017 were as follows: Three Months Ended March 31, 2018 2017 (Dollars in thousands) Balance at beginning of period $ 8,121 $ 9,778 Additions — — Reclassifications from nonaccretable 250 968 Accretion (686 ) (1,483 ) Balance at March 31 $ 7,685 $ 9,263
Carrying Amount of Non-PCI Loans and Related Outstanding Balance	The carrying amount of Non-PCI loans included in the consolidated balance sheet and the related outstanding balance as of the dates indicated are presented in the table below. The outstanding balance represents the total amount owed as of March 31, 2018 and December 31, 2017, including accrued but unpaid interest. March 31, 2018 December 31, 2017 (Dollars in thousands) Non-PCI loans: Outstanding balance $ 680,656 $ 738,706 Discount (18,885 ) (20,533 ) Recorded investment $ 661,771 $ 718,173
Changes in Discount Accretion for Non-PCI Loans	Changes in the discount accretion for Non-PCI loans for the three months ended March 31, 2018 and 2017 were as follows: Three Months Ended March 31, 2018 2017 (Dollars in thousands) Balance at beginning of period $ 20,533 $ 35,401 Additions — — Accretion charge-offs (8 ) (2 ) Accretion (1,640 ) (3,270 ) Balance at March 31 $ 18,885 $ 32,129
Summary of Impaired Loans	Impaired loans are set forth in the following tables. No interest income was recognized on impaired loans subsequent to their classification as impaired. The average recorded investment presented in the tables below is reported on a year-to-date basis. March 31, 2018 Recorded Investment Unpaid Contractual Principal Balance Related Allowance Average Recorded Investment (Dollars in thousands) With no related allowance recorded: Construction, land development and other land loans $ 509 $ 525 $ — $ 546 Agriculture and agriculture real estate (includes farmland) 1 2 — 66 1-4 family (includes home equity) 4,138 4,696 — 4,029 Commercial real estate (includes multi-family residential) 3,164 3,720 — 2,693 Commercial and industrial 10,555 18,125 — 9,201 Consumer and other 80 127 — 151 Total 18,447 27,195 — 16,686 With an allowance recorded: Construction, land development and other land loans — — — — Agriculture and agriculture real estate (includes farmland) 127 174 15 64 1-4 family (includes home equity) 915 945 165 1,053 Commercial real estate (includes multi-family residential) — — — 743 Commercial and industrial 2,842 3,103 957 4,497 Consumer and other — — — — Total 3,884 4,222 1,137 6,357 Total: Construction, land development and other land loans 509 525 — 546 Agriculture and agriculture real estate (includes farmland) 128 176 15 130 1-4 family (includes home equity) 5,053 5,641 165 5,082 Commercial real estate (includes multi-family residential) 3,164 3,720 — 3,436 Commercial and industrial 13,397 21,228 957 13,698 Consumer and other 80 127 — 151 $ 22,331 $ 31,417 $ 1,137 $ 23,043 December 31, 2017 Recorded Investment Unpaid Contractual Principal Balance Related Allowance Average Recorded Investment (Dollars in thousands) With no related allowance recorded: Construction, land development and other land loans $ 583 $ 600 $ — $ 298 Agriculture and agriculture real estate (includes farmland) 132 178 — 70 1-4 family (includes home equity) 3,920 4,181 — 3,185 Commercial real estate (includes multi-family residential) 2,222 2,254 — 2,703 Commercial and industrial 7,846 10,460 — 8,386 Consumer and other 222 269 — 170 Total 14,925 17,942 — 14,812 With an allowance recorded: Construction, land development and other land loans — — — — Agriculture and agriculture real estate (includes farmland) — — — 77 1-4 family (includes home equity) 1,191 1,213 559 814 Commercial real estate (includes multi-family residential) 1,486 1,499 366 887 Commercial and industrial 6,152 6,373 2,654 9,740 Consumer and other — — — 2 Total 8,829 9,085 3,579 11,520 Total: Construction, land development and other land loans 583 600 — 298 Agriculture and agriculture real estate (includes farmland) 132 178 — 147 1-4 family (includes home equity) 5,111 5,394 559 3,999 Commercial real estate (includes multi-family residential) 3,708 3,753 366 3,590 Commercial and industrial 13,998 16,833 2,654 18,126 Consumer and other 222 269 — 172 $ 23,754 $ 27,027 $ 3,579 $ 26,332
Risk Grades and PCI Loans by Category of Loan	The following table presents risk grades and PCI loans by category of loan at March 31, 2018. Impaired loans include loans in risk grades 7, 8 and 9, as well as any PCI loan that has a specific reserve allocated to it. Construction, Land Development and Other Agriculture and Agriculture Real Estate (includes Farmland) 1-4 Family (includes Home (1) Commercial Real Estate (includes Multi-Family Commercial and Industrial Consumer and Other Total (Dollars in thousands) Grade 1 $ — $ 14,036 $ — $ — $ 51,860 $ 38,151 $ 104,047 Grade 2 1,799 3,989 24,159 15,054 9,471 49,868 104,340 Grade 3 1,427,119 578,643 2,621,931 2,909,404 1,154,938 158,257 8,850,292 Grade 4 62,489 65,513 58,380 347,668 195,050 8,703 737,803 Grade 5 2,565 7,286 5,395 26,990 67,763 2,900 112,899 Grade 6 7,103 1,344 3,212 15,840 30,151 1,937 59,587 Grade 7 509 128 4,987 3,164 10,367 80 19,235 Grade 8 — — 66 — 3,030 — 3,096 Grade 9 — — — — — — — PCI Loans (2) 809 380 4,433 12,740 1,755 — 20,117 Total $ 1,502,393 $ 671,319 $ 2,722,563 $ 3,330,860 $ 1,524,385 $ 259,896 $ 10,011,416 (1) Includes $34.6 million of residential mortgage loans held for sale at March 31, 2018. (2) Of the total PCI loans, $241 thousand were classified as substandard at March 31, 2018, with no specific reserves allocated to them. The following table presents risk grades and PCI loans by category of loan at December 31, 2017. Impaired loans include loans in risk grades 7, 8 and 9, as well as any PCI loan that has a specific reserve allocated to it. Construction, Land Development and Other Agriculture and Agriculture Real Estate (includes Farmland) 1-4 Family (includes Home (1) Commercial Real Estate (includes Multi-Family Commercial and Industrial Consumer and Other Total (Dollars in thousands) Grade 1 $ — $ 14,084 $ — $ — $ 50,174 $ 38,029 $ 102,287 Grade 2 1,848 4,190 28,053 18,953 20,561 52,210 125,815 Grade 3 1,419,648 594,082 2,632,788 2,955,774 1,084,580 180,494 8,867,366 Grade 4 78,117 68,019 61,146 272,848 209,279 10,226 699,635 Grade 5 788 7,964 3,558 34,811 58,655 3,200 108,976 Grade 6 7,284 1,266 4,640 16,415 39,611 1,740 70,956 Grade 7 583 132 4,681 3,708 13,755 222 23,081 Grade 8 — — 430 — 243 — 673 Grade 9 — — — — — — — PCI Loans (2) 869 381 4,564 13,118 3,052 — 21,984 Total $ 1,509,137 $ 690,118 $ 2,739,860 $ 3,315,627 $ 1,479,910 $ 286,121 $ 10,020,773 (1) Includes $31.4 million of residential mortgage loans held for sale at December 31, 2017. (2) Of the total PCI loans, $1.5 million were classified as substandard at December 31, 2017, with no specific reserves allocated to them.
Allowance for Credit Losses by Category of Loan	The following table details activity in the allowance for credit losses by category of loan for the three months ended March 31, 2018 and 2017. Allocation of a portion of the allowance to one category of loans does not preclude its availability to absorb losses in other categories. Construction, Land Development and Other Land Loans Agriculture and Agriculture Real Estate (includes Farmland) 1-4 Family (includes Home Equity) Commercial Real Estate (includes Multi-Family Residential) Commercial and Industrial Consumer and Other Total (Dollars in thousands) Allowance for credit losses: Three Months Ended Balance December 31, 2017 $ 14,815 $ 3,772 $ 14,490 $ 10,628 $ 38,810 $ 1,526 $ 84,041 Provision for credit losses (70 ) (529 ) (1,161 ) 727 9,546 487 9,000 Charge-offs (130 ) — (266 ) (503 ) (8,176 ) (1,010 ) (10,085 ) Recoveries 7 61 9 1 160 406 644 Net charge-offs (123 ) 61 (257 ) (502 ) (8,016 ) (604 ) (9,441 ) Balance March 31, 2018 $ 14,622 $ 3,304 $ 13,072 $ 10,853 $ 40,340 $ 1,409 $ 83,600 Allowance for credit losses: Three Months Ended Balance December 31, 2016 $ 14,984 $ 4,073 $ 16,571 $ 12,256 $ 35,836 $ 1,606 $ 85,326 Provision for credit losses (386 ) (554 ) (895 ) (1,148 ) 5,341 317 2,675 Charge-offs — — (13 ) (133 ) (3,638 ) (824 ) (4,608 ) Recoveries 65 65 108 — 143 321 702 Net charge-offs 65 65 95 (133 ) (3,495 ) (503 ) (3,906 ) Balance March 31, 2017 $ 14,663 $ 3,584 $ 15,771 $ 10,975 $ 37,682 $ 1,420 $ 84,095 The following table details the amount of the allowance for credit losses allocated to each category of loan as of March 31, 2018, December 31, 2017 and March 31, 2017, on the basis of the impairment methodology used by the Company. Construction, Land Development and Other Land Loans Agriculture and Agriculture Real Estate (includes Farmland) 1-4 Family (includes Home Equity) Commercial Real Estate (includes Multi-Family Residential) Commercial and Industrial Consumer and Other Total (Dollars in thousands) Allowance for credit losses related March 31, 2018 Individually evaluated for impairment $ — $ 15 $ 165 $ — $ 957 $ — $ 1,137 Collectively evaluated for impairment 14,622 3,289 12,907 10,853 39,383 1,409 82,463 PCI loans — — — — — — — Total allowance for credit losses $ 14,622 $ 3,304 $ 13,072 $ 10,853 $ 40,340 $ 1,409 $ 83,600 December 31, 2017 Individually evaluated for impairment $ — $ — $ 559 $ 366 $ 2,654 $ — $ 3,579 Collectively evaluated for impairment 14,815 3,772 13,931 10,262 36,156 1,526 80,462 PCI loans — — — — — — — Total allowance for credit losses $ 14,815 $ 3,772 $ 14,490 $ 10,628 $ 38,810 $ 1,526 $ 84,041 March 31, 2017 Individually evaluated for impairment $ — $ 10 $ 113 $ — $ 1,203 $ 1 $ 1,327 Collectively evaluated for impairment 14,663 3,574 15,658 10,975 36,479 1,419 82,768 PCI loans — — — — — — — Total allowance for credit losses $ 14,663 $ 3,584 $ 15,771 $ 10,975 $ 37,682 $ 1,420 $ 84,095 The following table details the recorded investment in loans as of March 31, 2018, December 31, 2017 and March 31, 2017, excluding $34.6 million, $31.4 million and $21.9 million, respectively, of residential mortgage loans held for sale, related to each balance in the allowance for credit losses by category of loan. Construction, Land Development and Other Land Loans Agriculture and Agriculture Real Estate (includes Farmland) 1-4 Family (includes Home Equity) Commercial Real Estate (includes Multi-Family Residential) Commercial and Industrial Consumer and Other Total (Dollars in thousands) Recorded investment in March 31, 2018 Individually evaluated for impairment $ 509 $ 128 $ 5,053 $ 3,164 $ 13,397 $ 80 $ 22,331 Collectively evaluated for impairment 1,501,075 670,811 2,678,526 3,314,956 1,509,233 259,816 9,934,417 PCI loans 809 380 4,433 12,740 1,755 — 20,117 Total loans evaluated for impairment $ 1,502,393 $ 671,319 $ 2,688,012 $ 3,330,860 $ 1,524,385 $ 259,896 $ 9,976,865 December 31, 2017 Individually evaluated for impairment $ 583 $ 132 $ 5,111 $ 3,708 $ 13,998 $ 222 $ 23,754 Collectively evaluated for impairment 1,507,685 689,605 2,698,796 3,298,801 1,462,860 285,899 9,943,646 PCI loans 869 381 4,564 13,118 3,052 — 21,984 Total loans evaluated for impairment $ 1,509,137 $ 690,118 $ 2,708,471 $ 3,315,627 $ 1,479,910 $ 286,121 $ 9,989,384 March 31, 2017 Individually evaluated for impairment $ 231 $ 534 $ 3,168 $ 2,043 $ 16,666 $ 139 $ 22,781 Collectively evaluated for impairment 1,325,082 661,875 2,675,929 3,208,810 1,534,675 262,162 9,668,533 PCI loans 1,372 388 4,838 16,125 3,320 — 26,043 Total loans evaluated for impairment $ 1,326,685 $ 662,797 $ 2,683,935 $ 3,226,978 $ 1,554,661 $ 262,301 $ 9,717,357
Troubled Debt Restructurings	The following table presents information regarding the recorded investment of loans modified as troubled debt restructurings during the three months ended March 31, 2018 and 2017: Three Months Ended March 31, 2018 2017 Number of Loans Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Number of Loans Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment (Dollars in thousands) Troubled Debt Restructurings Construction, land development and other land loans — $ — $ — — $ — $ — Agriculture and agriculture real estate (includes farmland) — — — — — — 1-4 Family (includes home equity) — — — — — — Commercial real estate (includes multi-family residential) — — — — — — Commercial and industrial — — — 3 8,656 8,650 Consumer and other — — — — — — Total — $ — $ — 3 $ 8,656 $ 8,650

Fair Value (Tables)

Fair Value (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Assets and Liabilities Measured on Recurring Basis	The following tables present fair values for assets and liabilities measured at fair value on a recurring basis: As of March 31, 2018 Level 1 Level 2 Level 3 Total (Dollars in thousands) Assets: Available for sale securities: States and political subdivisions $ — $ 1,672 $ — $ 1,672 Collateralized mortgage obligations — 96,261 — 96,261 Mortgage-backed securities — 97,287 — 97,287 Other securities 12,269 — — 12,269 Total $ 12,269 $ 195,220 $ — $ 207,489 As of December 31, 2017 Level 1 Level 2 Level 3 Total (Dollars in thousands) Assets: Available for sale securities: States and political subdivisions $ — $ 1,820 $ — $ 1,820 Collateralized mortgage obligations — 100,061 — 100,061 Mortgage-backed securities — 103,489 — 103,489 Other securities 12,500 — — 12,500 Total $ 12,500 $ 205,370 $ — $ 217,870
Financial Instruments Fair Value	The following tables present carrying and fair value information of financial instruments as of the dates indicated: As of March 31, 2018 Carrying Estimated Fair Value Amount Level 1 Level 2 Level 3 Total Assets (Dollars in thousands) Cash and due from banks $ 243,514 $ 243,514 $ — $ — $ 243,514 Federal funds sold 469 469 — — 469 Held to maturity securities 9,502,765 — 9,239,443 — 9,239,443 Loans held for sale 34,551 — 34,551 — 34,551 Loans held for investment, net of allowance 9,893,265 — — 9,869,788 9,869,788 Other real estate owned 10,538 — 10,538 — 10,538 Liabilities Deposits: Noninterest-bearing $ 5,707,994 $ — $ 5,707,994 $ — $ 5,707,994 Interest-bearing 11,624,885 — 11,594,367 — 11,594,367 Other borrowings 820,079 — 820,184 — 820,184 Securities sold under repurchase agreements 339,576 — 339,532 — 339,532 As of December 31, 2017 Carrying Estimated Fair Value Amount Level 1 Level 2 Level 3 Total Assets (Dollars in thousands) Cash and due from banks $ 391,616 $ 391,616 $ — $ — $ 391,616 Federal funds sold 697 697 — — 697 Held to maturity securities 9,454,246 — 9,323,482 — 9,323,482 Loans held for sale 31,389 — 31,389 — 31,389 Loans held for investment, net of allowance 9,905,343 — — 9,923,556 9,923,556 Other real estate owned 11,152 — 11,152 — 11,152 Liabilities Deposits: Noninterest-bearing $ 5,623,322 $ — $ 5,623,322 $ — $ 5,623,322 Interest-bearing 12,198,138 — 12,173,164 — 12,173,164 Other borrowings 505,223 — 505,390 — 505,390 Securities sold under repurchase agreements 324,154 — 324,118 — 324,118

Goodwill and Core Deposit Int24

Goodwill and Core Deposit Intangibles (Tables)	3 Months Ended
	Mar. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Core Deposit Intangibles	Changes in the carrying amount of the Company’s goodwill and core deposit intangibles for the three months ended March 31, 2018 and the year ended December 31, 2017 were as follows: Goodwill Core Deposit Intangibles (Dollars in thousands) Balance as of December 31, 2016 $ 1,900,845 $ 45,784 Less: Amortization — (6,942 ) Balance as of December 31, 2017 1,900,845 38,842 Less: Amortization — (1,568 ) Balance as of March 31, 2018 $ 1,900,845 $ 37,274
Estimated Aggregate Future Amortization Expense for Core Deposit Intangibles	The estimated aggregate future amortization expense for core deposit intangibles remaining as of March 31, 2018 is as follows (dollars in thousands): Remaining 2018 $ 4,391 2019 5,051 2020 4,483 2021 4,022 2022 3,664 Thereafter 15,663 Total $ 37,274

Contractual Obligations and O25

Contractual Obligations and Off-Balance Sheet Items (Tables)	3 Months Ended
	Mar. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Schedule of Contractual Obligations and Other Commitments	The following table summarizes the Company’s contractual obligations and other commitments to make future payments as of March 31, 2018 (other than deposit obligations and securities sold under repurchase agreements). The Company’s future cash payments associated with its contractual obligations pursuant to its Federal Home Loan Bank (“FHLB”) notes payable and operating leases as of March 31, 2018 are summarized below. Payments for FHLB notes payable include interest of $290 thousand that will be paid over the future periods. Payments related to leases are based on actual payments specified in underlying contracts. 1 year or less More than 1 year but less than 3 years 3 years or more but less than 5 years 5 years or more Total (Dollars in thousands) Federal Home Loan Bank notes payable $ 819,207 $ 901 $ 125 $ 136 $ 820,369 Operating leases 4,895 7,290 3,736 4,676 20,597 Total $ 824,102 $ 8,191 $ 3,861 $ 4,812 $ 840,966
Summary of Commitments Associated with Outstanding Standby Letters of Credit and Commitments to Extend Credit	The Company’s commitments associated with outstanding standby letters of credit and commitments to extend credit expiring by period as of March 31, 2018 are summarized below. Since commitments associated with letters of credit and commitments to extend credit may expire unused, the amounts shown do not necessarily reflect the actual future cash funding requirements. 1 year or less More than 1 year but less than 3 years 3 years or more but less than 5 years 5 years or more Total (Dollars in thousands) Standby letters of credit $ 72,593 $ 5,389 $ 1,687 $ — $ 79,669 Commitments to extend credit 1,019,610 359,381 181,434 1,022,606 2,583,031 Total $ 1,092,203 $ 364,770 $ 183,121 $ 1,022,606 $ 2,662,700

Other Comprehensive Income (L26

Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Tax Effects Allocated to Each Component of Other Comprehensive Income (Loss)	The tax effects allocated to each component of other comprehensive income (loss) were as follows: Three Months Ended March 31, 2018 2017 Before Tax Amount Tax Effect Net of Tax Amount Before Tax Amount Tax Effect Net of Tax Amount (Dollars in thousands) Other comprehensive income: Securities available for sale: Change in unrealized gain during period $ 200 $ (42 ) $ 158 $ 29 $ (10 ) $ 19 Total securities available for sale 200 (42 ) 158 29 (10 ) 19 Total other comprehensive income $ 200 $ (42 ) $ 158 $ 29 $ (10 ) $ 19
Activity in Accumulated Other Comprehensive Income Associated with Securities Available for Sale, Net of Tax	Activity in accumulated other comprehensive income associated with securities available for sale, net of tax, was as follows: Securities Available for Sale Accumulated Other Comprehensive Income (Dollars in thousands) Balance at January 1, 2018 $ (113 ) $ (113 ) Other comprehensive income 158 158 Balance at March 31, 2018 $ 45 $ 45 Balance at January 1, 2017 $ 1,411 $ 1,411 Other comprehensive income 19 19 Balance at March 31, 2017 $ 1,430 $ 1,430

Income Per Common Share - Sched

Income Per Common Share - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Net income	$ 74,361	$ 68,565
Weighted average shares outstanding (in shares)	69,768,000	69,480,000
Weighted average shares outstanding (in dollars per share)	$ 1.07	$ 0.99
Effect of dilutive securities - options (in shares)		2,000
Total (in shares)	69,768,000	69,482,000
Total (in dollars per share)	$ 1.07	$ 0.99

Income Per Common Share Additio

Income Per Common Share Additional Information (Details) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	0

Securities - Schedule of Amorti

Securities - Schedule of 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]
Available for Sale Securities, Amortized Cost Basis	$ 207,432	$ 218,013
Available for Sale, Gross Unrealized Gains	1,760	1,342
Available for Sale, Gross Unrealized Losses	(1,703)	(1,485)
Available for Sale Securities	207,489	217,870
Held to Maturity, amortized cost, total	9,502,765	9,454,246
Held to Maturity, Gross Unrealized Gains	10,166	13,797
Held to Maturity, Gross Unrealized Losses	(273,488)	(144,561)
Held to Maturity securities	9,239,443	9,323,482
US States and Political Subdivisions Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for Sale Securities, Amortized Cost Basis	1,668	1,817
Available for Sale, Gross Unrealized Gains	4	3
Available for Sale Securities	1,672	1,820
Held to Maturity, amortized cost, total	290,040	328,666
Held to Maturity, Gross Unrealized Gains	4,058	4,263
Held to Maturity, Gross Unrealized Losses	(538)	(807)
Held to Maturity securities	293,560	332,122
Collateralized Mortgage Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for Sale Securities, Amortized Cost Basis	95,544	99,996
Available for Sale, Gross Unrealized Gains	770	122
Available for Sale, Gross Unrealized Losses	(53)	(57)
Available for Sale Securities	96,261	100,061
Held to Maturity, amortized cost, total	615	653
Held to Maturity, Gross Unrealized Gains	2	2
Held to Maturity, Gross Unrealized Losses	(4)	(5)
Held to Maturity securities	613	650
Collateralized Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for Sale Securities, Amortized Cost Basis	97,632	103,612
Available for Sale, Gross Unrealized Gains	986	1,204
Available for Sale, Gross Unrealized Losses	(1,331)	(1,327)
Available for Sale Securities	97,287	103,489
Held to Maturity, amortized cost, total	9,179,821	9,092,692
Held to Maturity, Gross Unrealized Gains	6,063	9,382
Held to Maturity, Gross Unrealized Losses	(272,907)	(143,744)
Held to Maturity securities	8,912,977	8,958,330
Other Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for Sale Securities, Amortized Cost Basis	12,588	12,588
Available for Sale, Gross Unrealized Gains		13
Available for Sale, Gross Unrealized Losses	(319)	(101)
Available for Sale Securities	12,269	12,500
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member]
Schedule Of Available For Sale Securities [Line Items]
Held to Maturity, amortized cost, total	32,289	32,235
Held to Maturity, Gross Unrealized Gains	43	150
Held to Maturity, Gross Unrealized Losses	(39)	(5)
Held to Maturity securities	$ 32,293	$ 32,380

Securities - Additional Informa

Securities - Additional Information (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018USD ($)SegmentSecurity	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)Security
Schedule Of Held To Maturity Securities [Line Items]
Gain on sale of securities	$ 0	$ 0
Available for Sale Securities, Amortized Cost Basis	207,432		$ 218,013
Available for sale securities, at fair value	$ 207,489		$ 217,870
Securities Concentration Risk [Member] | Stockholders' Equity, Total [Member]
Schedule Of Held To Maturity Securities [Line Items]
Concentration Risk, Percentage	10.00%		10.00%
Collateralized Securities [Member]
Schedule Of Held To Maturity Securities [Line Items]
Number of Investment Securities Segments | Segment	2
Other than Temporary Impairment Losses, Investments	$ 0
Securities in Unrealized Loss Positions Qualitative Disclosure Number of Positions Greater Than or Equal to One Year | Security	292		308
Available for Sale Securities, Amortized Cost Basis	$ 5,690,000		$ 5,940,000
Available for sale securities, at fair value	$ 5,500,000		$ 5,840,000

Securities - Securities in Cont

Securities - Securities in Continuous Loss Position (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule Of Available For Sale Securities [Line Items]
Available for Sale, Estimated Fair Value, Less than 12 Months	$ 56,218	$ 49,678
Available for Sale, Unrealized Losses, Less than 12 Months	(1,674)	(1,437)
Available for Sale, Estimated Fair Value, More than 12 Months	4,343	4,598
Available for Sale, Unrealized Losses, More than 12 Months	(29)	(48)
Available for Sale, Estimated Fair Value, Total	60,561	54,276
Available for Sale, Unrealized Losses, Total	(1,703)	(1,485)
Held to Maturity, Estimated Fair Value, Less than 12 Months	4,915,161	4,105,774
Held to Maturity, Unrealized Losses, Less than 12 Months	(107,397)	(34,939)
Held to Maturity, Estimated Fair Value, More than 12 Months	3,672,698	3,887,052
Held to Maturity, Unrealized Losses, More than 12 Months	(166,091)	(109,622)
Held to Maturity, Estimated Fair Value, Total	8,587,859	7,992,826
Held to Maturity, Unrealized Losses, Total	(273,488)	(144,561)
Collateralized Mortgage Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for Sale, Estimated Fair Value, Less than 12 Months	3,479	5,753
Available for Sale, Unrealized Losses, Less than 12 Months	(27)	(13)
Available for Sale, Estimated Fair Value, More than 12 Months	2,417	2,544
Available for Sale, Unrealized Losses, More than 12 Months	(26)	(44)
Available for Sale, Estimated Fair Value, Total	5,896	8,297
Available for Sale, Unrealized Losses, Total	(53)	(57)
Held to Maturity, Estimated Fair Value, Less than 12 Months	354	373
Held to Maturity, Unrealized Losses, Less than 12 Months	(4)	(2)
Held to Maturity, Estimated Fair Value, More than 12 Months		100
Held to Maturity, Unrealized Losses, More than 12 Months		(3)
Held to Maturity, Estimated Fair Value, Total	354	473
Held to Maturity, Unrealized Losses, Total	(4)	(5)
Collateralized Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for Sale, Estimated Fair Value, Less than 12 Months	40,470	42,289
Available for Sale, Unrealized Losses, Less than 12 Months	(1,328)	(1,323)
Available for Sale, Estimated Fair Value, More than 12 Months	1,926	2,054
Available for Sale, Unrealized Losses, More than 12 Months	(3)	(4)
Available for Sale, Estimated Fair Value, Total	42,396	44,343
Available for Sale, Unrealized Losses, Total	(1,331)	(1,327)
Held to Maturity, Estimated Fair Value, Less than 12 Months	4,802,646	3,940,075
Held to Maturity, Unrealized Losses, Less than 12 Months	(106,841)	(34,159)
Held to Maturity, Estimated Fair Value, More than 12 Months	3,669,817	3,883,266
Held to Maturity, Unrealized Losses, More than 12 Months	(166,066)	(109,585)
Held to Maturity, Estimated Fair Value, Total	8,472,463	7,823,341
Held to Maturity, Unrealized Losses, Total	(272,907)	(143,744)
Other Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for Sale, Estimated Fair Value, Less than 12 Months	12,269	1,636
Available for Sale, Unrealized Losses, Less than 12 Months	(319)	(101)
Available for Sale, Estimated Fair Value, Total	12,269	1,636
Available for Sale, Unrealized Losses, Total	(319)	(101)
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member]
Schedule Of Available For Sale Securities [Line Items]
Held to Maturity, Estimated Fair Value, Less than 12 Months	25,397	4,934
Held to Maturity, Unrealized Losses, Less than 12 Months	(39)	(5)
Held to Maturity, Estimated Fair Value, Total	25,397	4,934
Held to Maturity, Unrealized Losses, Total	(39)	(5)
US States and Political Subdivisions Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Held to Maturity, Estimated Fair Value, Less than 12 Months	86,764	160,392
Held to Maturity, Unrealized Losses, Less than 12 Months	(513)	(773)
Held to Maturity, Estimated Fair Value, More than 12 Months	2,881	3,686
Held to Maturity, Unrealized Losses, More than 12 Months	(25)	(34)
Held to Maturity, Estimated Fair Value, Total	89,645	164,078
Held to Maturity, Unrealized Losses, Total	$ (538)	$ (807)

Securities - Investment Securit

Securities - Investment Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Investments Debt And Equity Securities [Abstract]
Held to Maturity, amortized cost, due in one year or less	$ 37,102
Held to Maturity, amortized cost, due after one year through five years	161,835
Held to Maturity, amortized cost, due after five years through ten years	113,051
Held to Maturity, amortized cost, due after ten years	10,341
Held to Maturity, amortized cost, subtotal	322,329
Held to Maturity, amortized cost, mortgage-backed securities and collateralized mortgage obligations	9,180,436
Held to Maturity, amortized cost, total	9,502,765	$ 9,454,246
Held to Maturity, fair value, due in one year or less	37,237
Held to Maturity, fair value, due after one year through five years	162,424
Held to Maturity, fair value, due after five years through ten years	115,623
Held to Maturity, fair value, due after ten years	10,569
Held to Maturity, fair value, subtotal	325,853
Held to Maturity, fair value, mortgage-backed securities and collateralized mortgage obligations	8,913,590
Held to Maturity, fair value, total	9,239,443	$ 9,323,482
Available for Sale, amortized cost, due in one year or less	13,098
Available for Sale, amortized cost, due after one year through five years	1,158
Available for Sale, amortized cost, subtotal	14,256
Available for Sale, amortized cost, mortgage-backed securities and collateralized mortgage obligations	193,176
Available for Sale, amortized cost, total	207,432
Available for Sale, fair value, due in one year or less	12,779
Available for Sale, fair value, due after one year through five years	1,162
Available for Sale, fair value, subtotal	13,941
Available for Sale, fair value, mortgage-backed securities and collateralized mortgage obligations	193,548
Available for Sale securities, at fair value	$ 207,489

Loans and Allowance for Credi33

Loans and Allowance for Credit Losses - Types of Loans in Loan Portfolio (Details) - USD ($) $ in Thousands		Mar. 31, 2018		Dec. 31, 2017		Mar. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage		$ 34,551		$ 31,389
Total loans held for investment		9,976,865		9,989,384		$ 9,717,357
Total		10,011,416		10,020,773
Residential Portfolio Segment [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage		34,551		31,389
Commercial and Industrial [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans held for investment		1,524,385		1,479,910		1,554,661
Total		1,524,385		1,479,910
Construction, Land Development and Other Land Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans held for investment		1,502,393		1,509,137		1,326,685
Total		1,502,393		1,509,137
1-4 Family Residential (Includes Home Equity) [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage		34,600		31,400		21,900
Total loans held for investment		2,688,012		2,708,471		2,683,935
Total	[1]	2,722,563	[2]	2,739,860	[3]
Commercial Real Estate (Includes Multi-Family Residential) [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans held for investment		3,330,860		3,315,627		3,226,978
Total		3,330,860		3,315,627
Farmland [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans held for investment		507,874		502,841
Agriculture [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans held for investment		163,445		187,277
Consumer and Other [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loans held for investment		259,896		286,121		$ 262,301
Total		$ 259,896		$ 286,121
[1]	Includes $34.6 million and $31.4 million of residential mortgage loans held for sale at March 31, 2018 and December 31, 2017, respectively.
[2]	Includes $34.6 million of residential mortgage loans held for sale at March 31, 2018.
[3]	Includes $31.4 million of residential mortgage loans held for sale at December 31, 2017.

Loans and Allowance for Credi34

Loans and Allowance for Credit Losses - Additional Information (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2018USD ($)contract	Mar. 31, 2017USD ($)contract	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Accounts Notes And Loans Receivable [Line Items]
Percentage of real estate loans aggregating to company loan portfolio	75.10%
Loans held for investment	$ 9,976,865,000	$ 9,717,357,000	$ 9,989,384,000
Financing Receivable Ratio of Non-performing Loans to All Loans and Other Real Estate	0.33%		0.37%
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans	$ 526,000	$ 1,100,000
Nonaccrual loans	22,572,000		$ 25,264,000
Troubled debt restructurings, number of loans | contract		3
Troubled debt restructurings, pre-modification outstanding recorded investment		$ 8,656,000
Loans charged off	10,085,000	4,608,000
Troubled Debt Restructuring [Member]
Accounts Notes And Loans Receivable [Line Items]
Nonaccrual loans	50,000	$ 8,700,000
Nonperforming Financial Instruments [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans held for investment	$ 33,217,000		$ 37,455,000
Substandard [Member]
Accounts Notes And Loans Receivable [Line Items]
Percentage of Loans Related to Single Industry on Loans	10.00%		10.00%
Loans and Leases Receivable, Related Parties	$ 2,595,000		$ 2,694,000	$ 4,493,000
Minimum Period for Ceases Accruing Interest	90 days
Financing Receivable, Allowance for Credit Losses	$ 83,600,000		$ 84,000,000
Allowance for Credit Losses as Percentage of Loans	0.84%		0.84%
Troubled debt restructurings, number of loans | contract	0	3
Troubled debt restructurings, pre-modification outstanding recorded investment	$ 0	$ 8,700,000
Financing receivable, modifications, recorded investment		$ 8,700,000
Loan to be Considered as Payment Default in Period	90 days
Loans charged off	$ 0		$ 4,300,000

Loans and Allowance for Credi35

Loans and Allowance for Credit Losses - Related Party Loans (Details) - Substandard [Member] - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Beginning balance on January 1	$ 2,694	$ 4,493
New loans		175
Repayments and reclassified related loans	(99)	(1,974)
Ending balance	$ 2,595	$ 2,694

Loans and Allowance for Credi36

Loans and Allowance for Credit Losses - Aging Analysis of Past Due Loans (Details) - USD ($) $ in Thousands		Mar. 31, 2018		Dec. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Loans past due and still accruing		$ 18,714		$ 42,490
Nonaccrual loans		22,572		25,264
Current loans		9,970,130		9,953,019
Total loans		10,011,416		10,020,773
Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans past due and still accruing		18,607		41,486
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans past due and still accruing		107		1,004
Construction, Land Development and Other Land Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans past due and still accruing		3,859		8,634
Nonaccrual loans		509		583
Current loans		1,498,025		1,499,920
Total loans		1,502,393		1,509,137
Construction, Land Development and Other Land Loans [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans past due and still accruing		3,859		8,046
Construction, Land Development and Other Land Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans past due and still accruing				588
Agriculture and Agriculture Real Estate (Includes Farmland) [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans past due and still accruing		1,132		562
Nonaccrual loans		128		132
Current loans		670,059		689,424
Total loans		671,319		690,118
Agriculture and Agriculture Real Estate (Includes Farmland) [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans past due and still accruing		1,132		562
1-4 Family Residential (Includes Home Equity) [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans past due and still accruing	[1]	3,816		7,966
Nonaccrual loans	[1]	5,053		5,117
Current loans	[1]	2,713,694		2,726,777
Total loans	[1]	2,722,563	[2]	2,739,860	[3]
1-4 Family Residential (Includes Home Equity) [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans past due and still accruing	[1]	3,741		7,550
1-4 Family Residential (Includes Home Equity) [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans past due and still accruing	[1]	75		416
Commercial Real Estate (Includes Multi-Family Residential) [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans past due and still accruing		2,595		6,995
Nonaccrual loans		3,380		3,932
Current loans		3,324,885		3,304,700
Total loans		3,330,860		3,315,627
Commercial Real Estate (Includes Multi-Family Residential) [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans past due and still accruing		2,595		6,995
Commercial and Industrial [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans past due and still accruing		6,772		17,728
Nonaccrual loans		13,422		15,277
Current loans		1,504,191		1,446,905
Total loans		1,524,385		1,479,910
Commercial and Industrial [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans past due and still accruing		6,740		17,728
Commercial and Industrial [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans past due and still accruing		32
Consumer and Other [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans past due and still accruing		540		605
Nonaccrual loans		80		223
Current loans		259,276		285,293
Total loans		259,896		286,121
Consumer and Other [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans past due and still accruing		$ 540		$ 605
[1]	Includes $34.6 million and $31.4 million of residential mortgage loans held for sale at March 31, 2018 and December 31, 2017, respectively.
[2]	Includes $34.6 million of residential mortgage loans held for sale at March 31, 2018.
[3]	Includes $31.4 million of residential mortgage loans held for sale at December 31, 2017.

Loans and Allowance for Credi37

Loans and Allowance for Credit Losses - Aging Analysis of Past Due Loans (Parenthetical) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage	$ 34,551	$ 31,389
Residential Mortgage Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage	$ 34,600	$ 31,400

Loans and Allowance for Credi38

Loans and Allowance for Credit Losses - Nonperforming Assets (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Loans held for investment		$ 9,976,865	$ 9,989,384	$ 9,717,357
Nonperforming assets to total loans and other real estate		0.33%	0.37%
Nonperforming Financial Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans held for investment		$ 22,679	$ 26,268
Nonperforming Financial Loans [Member] | Finance Receivable Nonaccrual Status [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans held for investment	[1]	22,572	25,264
Nonperforming Financial Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans held for investment		107	1,004
Nonperforming Financial Instruments [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans held for investment		33,217	37,455
Nonperforming Financial Instruments [Member] | Repossessed Assets [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans held for investment			35
Nonperforming Financial Instruments [Member] | Other Real Assets [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans held for investment		$ 10,538	$ 11,152
[1]	Includes troubled debt restructurings of $50 thousand and $53 thousand as of March 31, 2018 and December 31, 2017, respectively.

Loans and Allowance for Credi39

Loans and Allowance for Credit Losses - Nonperforming Assets (Parenthetical) (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Loans held for investment		$ 9,976,865	$ 9,989,384	$ 9,717,357
Nonperforming Financial Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans held for investment		22,679	26,268
Nonperforming Financial Loans [Member] | Finance Receivable Nonaccrual Status [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans held for investment	[1]	22,572	25,264
Troubled Debt Restructuring [Member] | Nonperforming Financial Loans [Member] | Finance Receivable Nonaccrual Status [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans held for investment		$ 50	$ 53
[1]	Includes troubled debt restructurings of $50 thousand and $53 thousand as of March 31, 2018 and December 31, 2017, respectively.

Loans and Allowance for Credi40

Loans and Allowance for Credit Losses - Carrying Amount of PCI Loans and Related Outstanding Balance (Details) - Receivables Acquired with Deteriorated Credit Quality [Member] - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable Impaired [Line Items]
Outstanding balance	$ 30,503	$ 36,199
Discount	(10,386)	(14,215)
Recorded investment	$ 20,117	$ 21,984

Loans and Allowance for Credi41

Loans and Allowance for Credit Losses - Changes in Accretable Yield for Acquired PCI Loans (Details) - Receivables Acquired with Deteriorated Credit Quality [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Financing Receivable Impaired [Line Items]
Balance at beginning of period	$ 8,121	$ 9,778
Reclassifications from nonaccretable	250	968
Accretion	(686)	(1,483)
Balance at March 31	$ 7,685	$ 9,263

Loans and Allowance for Credi42

Loans and Allowance for Credit Losses - Carrying Amount of Non-PCI Loans and Related Outstanding Balance (Details) - Non PCI Loans [Member] - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable Impaired [Line Items]
Outstanding balance	$ 680,656	$ 738,706
Discount	(18,885)	(20,533)
Recorded investment	$ 661,771	$ 718,173

Loans and Allowance for Credi43

Loans and Allowance for Credit Losses - Changes in Discount Accretion for Non-PCI Loans (Details) - Non PCI Loans [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Financing Receivable Impaired [Line Items]
Balance at beginning of period	$ 20,533	$ 35,401
Accretion charge-offs	(8)	(2)
Accretion	(1,640)	(3,270)
Balance at March 31	$ 18,885	$ 32,129

Loans and Allowance for Credi44

Loans and Allowance for Credit Losses - Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance, recorded investment	$ 18,447	$ 14,925
Impaired loans with no related allowance, unpaid contractual principal balance	27,195	17,942
Impaired loans with no related allowance, average recorded investment	16,686	14,812
Impaired loans with related allowance, recorded investment	3,884	8,829
Impaired loans with related allowance, unpaid contractual principal balance	4,222	9,085
Impaired loans with related allowance, related allowance	1,137	3,579
Impaired loans with related allowance, average recorded investment	6,357	11,520
Impaired loans, recorded investment	22,331	23,754
Impaired loans, unpaid contractual principal balance	31,417	27,027
Impaired loans, average recorded investment	23,043	26,332
Impaired loans with an allowance recorded, related allowance	1,137	3,579
Construction, Land Development and Other Land Loans [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance, recorded investment	509	583
Impaired loans with no related allowance, unpaid contractual principal balance	525	600
Impaired loans with no related allowance, average recorded investment	546	298
Impaired loans, recorded investment	509	583
Impaired loans, unpaid contractual principal balance	525	600
Impaired loans, average recorded investment	546	298
Agriculture and Agriculture Real Estate (Includes Farmland) [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance, recorded investment	1	132
Impaired loans with no related allowance, unpaid contractual principal balance	2	178
Impaired loans with no related allowance, average recorded investment	66	70
Impaired loans with related allowance, recorded investment	127
Impaired loans with related allowance, unpaid contractual principal balance	174
Impaired loans with related allowance, related allowance	15
Impaired loans with related allowance, average recorded investment	64	77
Impaired loans, recorded investment	128	132
Impaired loans, unpaid contractual principal balance	176	178
Impaired loans, average recorded investment	130	147
1-4 Family Residential (Includes Home Equity) [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance, recorded investment	4,138	3,920
Impaired loans with no related allowance, unpaid contractual principal balance	4,696	4,181
Impaired loans with no related allowance, average recorded investment	4,029	3,185
Impaired loans with related allowance, recorded investment	915	1,191
Impaired loans with related allowance, unpaid contractual principal balance	945	1,213
Impaired loans with related allowance, related allowance	165	559
Impaired loans with related allowance, average recorded investment	1,053	814
Impaired loans, recorded investment	5,053	5,111
Impaired loans, unpaid contractual principal balance	5,641	5,394
Impaired loans, average recorded investment	5,082	3,999
Commercial Real Estate (Includes Multi-Family Residential) [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance, recorded investment	3,164	2,222
Impaired loans with no related allowance, unpaid contractual principal balance	3,720	2,254
Impaired loans with no related allowance, average recorded investment	2,693	2,703
Impaired loans with related allowance, recorded investment		1,486
Impaired loans with related allowance, unpaid contractual principal balance		1,499
Impaired loans with related allowance, related allowance		366
Impaired loans with related allowance, average recorded investment	743	887
Impaired loans, recorded investment	3,164	3,708
Impaired loans, unpaid contractual principal balance	3,720	3,753
Impaired loans, average recorded investment	3,436	3,590
Commercial and Industrial [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance, recorded investment	10,555	7,846
Impaired loans with no related allowance, unpaid contractual principal balance	18,125	10,460
Impaired loans with no related allowance, average recorded investment	9,201	8,386
Impaired loans with related allowance, recorded investment	2,842	6,152
Impaired loans with related allowance, unpaid contractual principal balance	3,103	6,373
Impaired loans with related allowance, related allowance	957	2,654
Impaired loans with related allowance, average recorded investment	4,497	9,740
Impaired loans, recorded investment	13,397	13,998
Impaired loans, unpaid contractual principal balance	21,228	16,833
Impaired loans, average recorded investment	13,698	18,126
Consumer and Other [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance, recorded investment	80	222
Impaired loans with no related allowance, unpaid contractual principal balance	127	269
Impaired loans with no related allowance, average recorded investment	151	170
Impaired loans with related allowance, average recorded investment		2
Impaired loans, recorded investment	80	222
Impaired loans, unpaid contractual principal balance	127	269
Impaired loans, average recorded investment	$ 151	$ 172

Loans and Allowance for Credi45

Loans and Allowance for Credit Losses - Risk Grades and PCI Loans by Category of Loan (Details) - USD ($) $ in Thousands		Mar. 31, 2018		Dec. 31, 2017
Financing Receivable Impaired [Line Items]
Loans		$ 10,011,416		$ 10,020,773
Grade 1 [Member]
Financing Receivable Impaired [Line Items]
Loans		104,047		102,287
Grade 2 [Member]
Financing Receivable Impaired [Line Items]
Loans		104,340		125,815
Grade 3 [Member]
Financing Receivable Impaired [Line Items]
Loans		8,850,292		8,867,366
Grade 4 [Member]
Financing Receivable Impaired [Line Items]
Loans		737,803		699,635
Grade 5 [Member]
Financing Receivable Impaired [Line Items]
Loans		112,899		108,976
Grade 6 [Member]
Financing Receivable Impaired [Line Items]
Loans		59,587		70,956
Grade 7 [Member]
Financing Receivable Impaired [Line Items]
Loans		19,235		23,081
Grade 8 [Member]
Financing Receivable Impaired [Line Items]
Loans		3,096		673
PCI Loans [Member]
Financing Receivable Impaired [Line Items]
Loans		20,117	[1]	21,984	[2]
Construction, Land Development and Other Land Loans [Member]
Financing Receivable Impaired [Line Items]
Loans		1,502,393		1,509,137
Construction, Land Development and Other Land Loans [Member] | Grade 2 [Member]
Financing Receivable Impaired [Line Items]
Loans		1,799		1,848
Construction, Land Development and Other Land Loans [Member] | Grade 3 [Member]
Financing Receivable Impaired [Line Items]
Loans		1,427,119		1,419,648
Construction, Land Development and Other Land Loans [Member] | Grade 4 [Member]
Financing Receivable Impaired [Line Items]
Loans		62,489		78,117
Construction, Land Development and Other Land Loans [Member] | Grade 5 [Member]
Financing Receivable Impaired [Line Items]
Loans		2,565		788
Construction, Land Development and Other Land Loans [Member] | Grade 6 [Member]
Financing Receivable Impaired [Line Items]
Loans		7,103		7,284
Construction, Land Development and Other Land Loans [Member] | Grade 7 [Member]
Financing Receivable Impaired [Line Items]
Loans		509		583
Construction, Land Development and Other Land Loans [Member] | PCI Loans [Member]
Financing Receivable Impaired [Line Items]
Loans		809	[1]	869	[2]
Agriculture and Agriculture Real Estate (Includes Farmland) [Member]
Financing Receivable Impaired [Line Items]
Loans		671,319		690,118
Agriculture and Agriculture Real Estate (Includes Farmland) [Member] | Grade 1 [Member]
Financing Receivable Impaired [Line Items]
Loans		14,036		14,084
Agriculture and Agriculture Real Estate (Includes Farmland) [Member] | Grade 2 [Member]
Financing Receivable Impaired [Line Items]
Loans		3,989		4,190
Agriculture and Agriculture Real Estate (Includes Farmland) [Member] | Grade 3 [Member]
Financing Receivable Impaired [Line Items]
Loans		578,643		594,082
Agriculture and Agriculture Real Estate (Includes Farmland) [Member] | Grade 4 [Member]
Financing Receivable Impaired [Line Items]
Loans		65,513		68,019
Agriculture and Agriculture Real Estate (Includes Farmland) [Member] | Grade 5 [Member]
Financing Receivable Impaired [Line Items]
Loans		7,286		7,964
Agriculture and Agriculture Real Estate (Includes Farmland) [Member] | Grade 6 [Member]
Financing Receivable Impaired [Line Items]
Loans		1,344		1,266
Agriculture and Agriculture Real Estate (Includes Farmland) [Member] | Grade 7 [Member]
Financing Receivable Impaired [Line Items]
Loans		128		132
Agriculture and Agriculture Real Estate (Includes Farmland) [Member] | PCI Loans [Member]
Financing Receivable Impaired [Line Items]
Loans		380	[1]	381	[2]
1-4 Family Residential (Includes Home Equity) [Member]
Financing Receivable Impaired [Line Items]
Loans	[3]	2,722,563	[4]	2,739,860	[5]
1-4 Family Residential (Includes Home Equity) [Member] | Grade 2 [Member]
Financing Receivable Impaired [Line Items]
Loans		24,159	[4]	28,053	[5]
1-4 Family Residential (Includes Home Equity) [Member] | Grade 3 [Member]
Financing Receivable Impaired [Line Items]
Loans		2,621,931	[4]	2,632,788	[5]
1-4 Family Residential (Includes Home Equity) [Member] | Grade 4 [Member]
Financing Receivable Impaired [Line Items]
Loans		58,380	[4]	61,146	[5]
1-4 Family Residential (Includes Home Equity) [Member] | Grade 5 [Member]
Financing Receivable Impaired [Line Items]
Loans		5,395	[4]	3,558	[5]
1-4 Family Residential (Includes Home Equity) [Member] | Grade 6 [Member]
Financing Receivable Impaired [Line Items]
Loans		3,212	[4]	4,640	[5]
1-4 Family Residential (Includes Home Equity) [Member] | Grade 7 [Member]
Financing Receivable Impaired [Line Items]
Loans		4,987	[4]	4,681	[5]
1-4 Family Residential (Includes Home Equity) [Member] | Grade 8 [Member]
Financing Receivable Impaired [Line Items]
Loans		66	[4]	430	[5]
1-4 Family Residential (Includes Home Equity) [Member] | PCI Loans [Member]
Financing Receivable Impaired [Line Items]
Loans		4,433	[1],[4]	4,564	[2],[5]
Commercial Real Estate (Includes Multi-Family Residential) [Member]
Financing Receivable Impaired [Line Items]
Loans		3,330,860		3,315,627
Commercial Real Estate (Includes Multi-Family Residential) [Member] | Grade 2 [Member]
Financing Receivable Impaired [Line Items]
Loans		15,054		18,953
Commercial Real Estate (Includes Multi-Family Residential) [Member] | Grade 3 [Member]
Financing Receivable Impaired [Line Items]
Loans		2,909,404		2,955,774
Commercial Real Estate (Includes Multi-Family Residential) [Member] | Grade 4 [Member]
Financing Receivable Impaired [Line Items]
Loans		347,668		272,848
Commercial Real Estate (Includes Multi-Family Residential) [Member] | Grade 5 [Member]
Financing Receivable Impaired [Line Items]
Loans		26,990		34,811
Commercial Real Estate (Includes Multi-Family Residential) [Member] | Grade 6 [Member]
Financing Receivable Impaired [Line Items]
Loans		15,840		16,415
Commercial Real Estate (Includes Multi-Family Residential) [Member] | Grade 7 [Member]
Financing Receivable Impaired [Line Items]
Loans		3,164		3,708
Commercial Real Estate (Includes Multi-Family Residential) [Member] | PCI Loans [Member]
Financing Receivable Impaired [Line Items]
Loans		12,740	[1]	13,118	[2]
Commercial and Industrial [Member]
Financing Receivable Impaired [Line Items]
Loans		1,524,385		1,479,910
Commercial and Industrial [Member] | Grade 1 [Member]
Financing Receivable Impaired [Line Items]
Loans		51,860		50,174
Commercial and Industrial [Member] | Grade 2 [Member]
Financing Receivable Impaired [Line Items]
Loans		9,471		20,561
Commercial and Industrial [Member] | Grade 3 [Member]
Financing Receivable Impaired [Line Items]
Loans		1,154,938		1,084,580
Commercial and Industrial [Member] | Grade 4 [Member]
Financing Receivable Impaired [Line Items]
Loans		195,050		209,279
Commercial and Industrial [Member] | Grade 5 [Member]
Financing Receivable Impaired [Line Items]
Loans		67,763		58,655
Commercial and Industrial [Member] | Grade 6 [Member]
Financing Receivable Impaired [Line Items]
Loans		30,151		39,611
Commercial and Industrial [Member] | Grade 7 [Member]
Financing Receivable Impaired [Line Items]
Loans		10,367		13,755
Commercial and Industrial [Member] | Grade 8 [Member]
Financing Receivable Impaired [Line Items]
Loans		3,030		243
Commercial and Industrial [Member] | PCI Loans [Member]
Financing Receivable Impaired [Line Items]
Loans		1,755	[1]	3,052	[2]
Consumer and Other [Member]
Financing Receivable Impaired [Line Items]
Loans		259,896		286,121
Consumer and Other [Member] | Grade 1 [Member]
Financing Receivable Impaired [Line Items]
Loans		38,151		38,029
Consumer and Other [Member] | Grade 2 [Member]
Financing Receivable Impaired [Line Items]
Loans		49,868		52,210
Consumer and Other [Member] | Grade 3 [Member]
Financing Receivable Impaired [Line Items]
Loans		158,257		180,494
Consumer and Other [Member] | Grade 4 [Member]
Financing Receivable Impaired [Line Items]
Loans		8,703		10,226
Consumer and Other [Member] | Grade 5 [Member]
Financing Receivable Impaired [Line Items]
Loans		2,900		3,200
Consumer and Other [Member] | Grade 6 [Member]
Financing Receivable Impaired [Line Items]
Loans		1,937		1,740
Consumer and Other [Member] | Grade 7 [Member]
Financing Receivable Impaired [Line Items]
Loans		$ 80		$ 222
[1]	Of the total PCI loans, $241 thousand were classified as substandard at March 31, 2018, with no specific reserves allocated to them.
[2]	Of the total PCI loans, $1.5 million were classified as substandard at December 31, 2017, with no specific reserves allocated to them.
[3]	Includes $34.6 million and $31.4 million of residential mortgage loans held for sale at March 31, 2018 and December 31, 2017, respectively.
[4]	Includes $34.6 million of residential mortgage loans held for sale at March 31, 2018.
[5]	Includes $31.4 million of residential mortgage loans held for sale at December 31, 2017.

Loans and Allowance for Credi46

Loans and Allowance for Credit Losses - Risk Grades and Impaired Loans by Class of Loan (Parenthetical) (Details) - USD ($)	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Financing Receivable Impaired [Line Items]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage	$ 34,551,000	$ 31,389,000
Substandard [Member]
Financing Receivable Impaired [Line Items]
Loans Receivable, Fair Value Disclosure	241,000	1,500,000
Allocated Specific Reserves	0	0
1-4 Family Residential (Includes Home Equity) [Member]
Financing Receivable Impaired [Line Items]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage	$ 34,600,000	$ 31,400,000	$ 21,900,000

Loans and Allowance for Credi47

Loans and Allowance for Credit Losses - Allowance for Credit Losses by Category of Loan (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Allowance for credit losses:
Allowance for credit losses, beginning balance	$ 84,041	$ 85,326	$ 85,326
Provision for credit losses	9,000	2,675
Charge-offs	(10,085)	(4,608)
Recoveries	644	702
Net charge-offs	(9,441)	(3,906)
Allowance for credit losses, ending balance	83,600	84,095	84,041
Allowance for credit losses related to:
Allowance for credit losses, individually evaluated for impairment				$ 1,137	$ 3,579	$ 1,327
Allowance for credit losses, collectively evaluated for impairment				82,463	80,462	82,768
Total allowance for credit losses	83,600	85,326	84,041	83,600	84,041	84,095
Recorded investment in loans:
Loans, individually evaluated for impairment				22,331	23,754	22,781
Loans, collectively evaluated for impairment				9,934,417	9,943,646	9,668,533
PCI loans				20,117	21,984	26,043
Total loans evaluated for impairment				9,976,865	9,989,384	9,717,357
Construction, Land Development and Other Land Loans [Member]
Allowance for credit losses:
Allowance for credit losses, beginning balance	14,815	14,984	14,984
Provision for credit losses	(70)	(386)
Charge-offs	(130)
Recoveries	7	65
Net charge-offs	(123)	65
Allowance for credit losses, ending balance	14,622	14,663	14,815
Allowance for credit losses related to:
Allowance for credit losses, collectively evaluated for impairment				14,622	14,815	14,663
Total allowance for credit losses	14,815	14,984	14,815	14,622	14,815	14,663
Recorded investment in loans:
Loans, individually evaluated for impairment				509	583	231
Loans, collectively evaluated for impairment				1,501,075	1,507,685	1,325,082
PCI loans				809	869	1,372
Total loans evaluated for impairment				1,502,393	1,509,137	1,326,685
Agriculture and Agriculture Real Estate (Includes Farmland) [Member]
Allowance for credit losses:
Allowance for credit losses, beginning balance	3,772	4,073	4,073
Provision for credit losses	(529)	(554)
Recoveries	61	65
Net charge-offs	61	65
Allowance for credit losses, ending balance	3,304	3,584	3,772
Allowance for credit losses related to:
Allowance for credit losses, individually evaluated for impairment				15		10
Allowance for credit losses, collectively evaluated for impairment				3,289	3,772	3,574
Total allowance for credit losses	3,772	4,073	3,772	3,304	3,772	3,584
Recorded investment in loans:
Loans, individually evaluated for impairment				128	132	534
Loans, collectively evaluated for impairment				670,811	689,605	661,875
PCI loans				380	381	388
Total loans evaluated for impairment				671,319	690,118	662,797
1-4 Family Residential (Includes Home Equity) [Member]
Allowance for credit losses:
Allowance for credit losses, beginning balance	14,490	16,571	16,571
Provision for credit losses	(1,161)	(895)
Charge-offs	(266)	(13)
Recoveries	9	108
Net charge-offs	(257)	95
Allowance for credit losses, ending balance	13,072	15,771	14,490
Allowance for credit losses related to:
Allowance for credit losses, individually evaluated for impairment				165	559	113
Allowance for credit losses, collectively evaluated for impairment				12,907	13,931	15,658
Total allowance for credit losses	14,490	16,571	14,490	13,072	14,490	15,771
Recorded investment in loans:
Loans, individually evaluated for impairment				5,053	5,111	3,168
Loans, collectively evaluated for impairment				2,678,526	2,698,796	2,675,929
PCI loans				4,433	4,564	4,838
Total loans evaluated for impairment				2,688,012	2,708,471	2,683,935
Commercial Real Estate (Includes Multi-Family Residential) [Member]
Allowance for credit losses:
Allowance for credit losses, beginning balance	10,628	12,256	12,256
Provision for credit losses	727	(1,148)
Charge-offs	(503)	(133)
Recoveries	1
Net charge-offs	(502)	(133)
Allowance for credit losses, ending balance	10,853	10,975	10,628
Allowance for credit losses related to:
Allowance for credit losses, individually evaluated for impairment					366
Allowance for credit losses, collectively evaluated for impairment				10,853	10,262	10,975
Total allowance for credit losses	10,628	12,256	10,628	10,853	10,628	10,975
Recorded investment in loans:
Loans, individually evaluated for impairment				3,164	3,708	2,043
Loans, collectively evaluated for impairment				3,314,956	3,298,801	3,208,810
PCI loans				12,740	13,118	16,125
Total loans evaluated for impairment				3,330,860	3,315,627	3,226,978
Commercial and Industrial [Member]
Allowance for credit losses:
Allowance for credit losses, beginning balance	38,810	35,836	35,836
Provision for credit losses	9,546	5,341
Charge-offs	(8,176)	(3,638)
Recoveries	160	143
Net charge-offs	(8,016)	(3,495)
Allowance for credit losses, ending balance	40,340	37,682	38,810
Allowance for credit losses related to:
Allowance for credit losses, individually evaluated for impairment				957	2,654	1,203
Allowance for credit losses, collectively evaluated for impairment				39,383	36,156	36,479
Total allowance for credit losses	38,810	35,836	38,810	40,340	38,810	37,682
Recorded investment in loans:
Loans, individually evaluated for impairment				13,397	13,998	16,666
Loans, collectively evaluated for impairment				1,509,233	1,462,860	1,534,675
PCI loans				1,755	3,052	3,320
Total loans evaluated for impairment				1,524,385	1,479,910	1,554,661
Consumer and Other [Member]
Allowance for credit losses:
Allowance for credit losses, beginning balance	1,526	1,606	1,606
Provision for credit losses	487	317
Charge-offs	(1,010)	(824)
Recoveries	406	321
Net charge-offs	(604)	(503)
Allowance for credit losses, ending balance	1,409	1,420	1,526
Allowance for credit losses related to:
Allowance for credit losses, individually evaluated for impairment						1
Allowance for credit losses, collectively evaluated for impairment				1,409	1,526	1,419
Total allowance for credit losses	$ 1,526	$ 1,606	$ 1,526	1,409	1,526	1,420
Recorded investment in loans:
Loans, individually evaluated for impairment				80	222	139
Loans, collectively evaluated for impairment				259,816	285,899	262,162
Total loans evaluated for impairment				$ 259,896	$ 286,121	$ 262,301

Loans and Allowance for Credi48

Loans and Allowance for Credit Losses - Allowance for Credit Losses by Category of Loan (Parenthetical) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage	$ 34,551	$ 31,389
1-4 Family Residential (Includes Home Equity) [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage	$ 34,600	$ 31,400	$ 21,900

Loans and Allowance for Credi49

Loans and Allowance for Credit Losses - Troubled Debt Restructurings (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)contract
Financing Receivable Modifications [Line Items]
Troubled debt restructurings, number of loans | contract	3
Troubled debt restructurings, pre-modification outstanding recorded investment	$ 8,656
Troubled debt restructurings, post-modification outstanding recorded investment	$ 8,650
Commercial and Industrial [Member]
Financing Receivable Modifications [Line Items]
Troubled debt restructurings, number of loans | contract	3
Troubled debt restructurings, pre-modification outstanding recorded investment	$ 8,656
Troubled debt restructurings, post-modification outstanding recorded investment	$ 8,650

Fair Value - Fair Value Assets

Fair Value - Fair Value Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Available for sale securities:
Available for sale securities, at fair value	$ 207,489	$ 217,870
Fair Value, Measurements, Recurring [Member]
Available for sale securities:
Available for sale securities, at fair value	207,489	217,870
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Available for sale securities:
Available for sale securities, at fair value	12,269	12,500
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Available for sale securities:
Available for sale securities, at fair value	195,220	205,370
Fair Value, Measurements, Recurring [Member] | States and Political Subdivisions [Member]
Available for sale securities:
Available for sale securities, at fair value	1,672	1,820
Fair Value, Measurements, Recurring [Member] | States and Political Subdivisions [Member] | Level 2 [Member]
Available for sale securities:
Available for sale securities, at fair value	1,672	1,820
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Obligations [Member]
Available for sale securities:
Available for sale securities, at fair value	96,261	100,061
Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Obligations [Member] | Level 2 [Member]
Available for sale securities:
Available for sale securities, at fair value	96,261	100,061
Fair Value, Measurements, Recurring [Member] | Mortgage-backed Securities [Member]
Available for sale securities:
Available for sale securities, at fair value	97,287	103,489
Fair Value, Measurements, Recurring [Member] | Mortgage-backed Securities [Member] | Level 2 [Member]
Available for sale securities:
Available for sale securities, at fair value	97,287	103,489
Fair Value, Measurements, Recurring [Member] | Other Securities [Member]
Available for sale securities:
Available for sale securities, at fair value	12,269	12,500
Fair Value, Measurements, Recurring [Member] | Other Securities [Member] | Level 1 [Member]
Available for sale securities:
Available for sale securities, at fair value	$ 12,269	$ 12,500

Fair Value - Additional Informa

Fair Value - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Fair Value Disclosures [Abstract]
Other real estate, additions	$ 47
Real estate owned outstanding	47
Additions to impaired loans	7,000
Impaired loans outstanding	$ 7,000

Fair Value - Financial Instrume

Fair Value - Financial Instruments Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Assets
Cash and due from banks	$ 243,514	$ 391,616
Federal funds sold	469	697
Held to Maturity securities	9,239,443	9,323,482
Loans held for sale	34,551	31,389
Other real estate owned	10,538	11,152
Liabilities
Noninterest-bearing	5,707,994	5,623,322
Interest-bearing	11,624,885	12,198,138
Other borrowings	820,079	505,223
Securities sold under repurchase agreements	339,576	324,154
Carrying Amount [Member]
Assets
Cash and due from banks	243,514	391,616
Federal funds sold	469	697
Held to Maturity securities	9,502,765	9,454,246
Loans held for sale	34,551	31,389
Loans held for investment, net of allowance	9,893,265	9,905,343
Other real estate owned	10,538	11,152
Liabilities
Noninterest-bearing	5,707,994	5,623,322
Interest-bearing	11,624,885	12,198,138
Other borrowings	820,079	505,223
Securities sold under repurchase agreements	339,576	324,154
Estimated Fair Value [Member]
Assets
Cash and due from banks	243,514	391,616
Federal funds sold	469	697
Held to Maturity securities	9,239,443	9,323,482
Loans held for sale	34,551	31,389
Loans held for investment, net of allowance	9,869,788	9,923,556
Other real estate owned	10,538	11,152
Liabilities
Noninterest-bearing	5,707,994	5,623,322
Interest-bearing	11,594,367	12,173,164
Other borrowings	820,184	505,390
Securities sold under repurchase agreements	339,532	324,118
Estimated Fair Value [Member] | Level 1 [Member]
Assets
Cash and due from banks	243,514	391,616
Federal funds sold	469	697
Estimated Fair Value [Member] | Level 2 [Member]
Assets
Held to Maturity securities	9,239,443	9,323,482
Loans held for sale	34,551	31,389
Other real estate owned	10,538	11,152
Liabilities
Noninterest-bearing	5,707,994	5,623,322
Interest-bearing	11,594,367	12,173,164
Other borrowings	820,184	505,390
Securities sold under repurchase agreements	339,532	324,118
Estimated Fair Value [Member] | Level 3 [Member]
Assets
Loans held for investment, net of allowance	$ 9,869,788	$ 9,923,556

Goodwill and Core Deposit Int53

Goodwill and Core Deposit Intangibles - Goodwill and Core Deposit Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Schedule Of Intangible Assets And Goodwill [Line Items]
Goodwill, Beginning balance	$ 1,900,845	$ 1,900,845	$ 1,900,845
Goodwill, Ending balance	1,900,845		1,900,845
Core Deposit Intangibles, Beginning balance	38,842
Core Deposit Intangibles, Amortization	(1,568)	(1,915)
Core Deposit Intangibles, Ending balance	37,274		38,842
Core Deposit Intangibles [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Core Deposit Intangibles, Beginning balance	38,842	45,784	45,784
Core Deposit Intangibles, Amortization	(1,568)	$ (1,900)	(6,942)
Core Deposit Intangibles, Ending balance	$ 37,274		$ 38,842

Goodwill and Core Deposit Int54

Goodwill and Core Deposit Intangibles - Additional Information (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Schedule Of Intangible Assets And Goodwill [Line Items]
Amortization expense related to intangible assets	$ 1,568,000	$ 1,915,000
Core Deposit Intangibles [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Impairment recorded on goodwill and core deposit intangibles	0
Amortization expense related to intangible assets	$ 1,568,000	$ 1,900,000	$ 6,942,000
Core Deposit Intangibles [Member] | Minimum [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Finite-lived intangible assets, useful life	10 years
Core Deposit Intangibles [Member] | Maximum [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Finite-lived intangible assets, useful life	15 years

Goodwill and Core Deposit Int55

Goodwill and Core Deposit Intangibles - Estimated Aggregate Future Amortization Expense for Core Deposit Intangibles (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite Lived Intangible Assets [Line Items]
Total	$ 37,274	$ 38,842
Core Deposits [Member]
Finite Lived Intangible Assets [Line Items]
Remaining 2,018	4,391
2,019	5,051
2,020	4,483
2,021	4,022
2,022	3,664
Thereafter	15,663
Total	$ 37,274	$ 38,842	$ 45,784

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)Planshares	Mar. 31, 2017USD ($)shares	Dec. 31, 2012shares	Dec. 31, 2004shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Stock-Based Employee Compensation Plans | Plan	2
Number of Stock-Based Employee Compensation Plans Expired | Plan	1
Proceeds from stock option exercises | $	$ 0	$ 148
Tax benefit realized from exercises of stock-based compensation arrangements | $	$ 0	$ 0
Number of shares outstanding	0	0
Total unrecognized compensation expense related to stock-based compensation arrangements | $	$ 26,700
Weighted-average period of cost expected to be recognized	2 years 14 days
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense | $	$ 2,600	$ 1,700
2004 Stock Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized				1,250,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	0
2012 Stock Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized			1,250,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	692,109

Contractual Obligations and O57

Contractual Obligations and Off-Balance Sheet Items - Additional Information (Details) $ in Thousands	Mar. 31, 2018USD ($)
Federal Home Loan Bank Notes Payable [Member]
Contractual Obligations And Off Balance Sheet Items [Line Items]
Interest payable	$ 290

Contractual Obligations and O58

Contractual Obligations and Off-Balance Sheet Items - Contractual Obligations and Other Commitments (Details) - Lease Total [Member] $ in Thousands	Mar. 31, 2018USD ($)
Contractual Obligations And Off Balance Sheet Items [Line Items]
1 year or less	$ 824,102
More than 1 year but less than 3 years	8,191
3 years or more but less than 5 years	3,861
5 years or more	4,812
Total	840,966
Federal Home Loan Bank Notes Payable [Member]
Contractual Obligations And Off Balance Sheet Items [Line Items]
1 year or less	819,207
More than 1 year but less than 3 years	901
3 years or more but less than 5 years	125
5 years or more	136
Total	820,369
Operating Leases [Member]
Contractual Obligations And Off Balance Sheet Items [Line Items]
1 year or less	4,895
More than 1 year but less than 3 years	7,290
3 years or more but less than 5 years	3,736
5 years or more	4,676
Total	$ 20,597

Contractual Obligations and O59

Contractual Obligations and Off-Balance Sheet Items - Summary of Commitments Associated with Outstanding Standby Letters of Credit and Commitments to Extend Credit (Details) - Guarantee Obligations [Member] $ in Thousands	Mar. 31, 2018USD ($)
Contractual Obligations And Off Balance Sheet Items [Line Items]
1 year or less	$ 1,092,203
More than 1 year but less than 3 years	364,770
3 years or more but less than 5 years	183,121
5 years or more	1,022,606
Total	2,662,700
Financial Guarantee [Member]
Contractual Obligations And Off Balance Sheet Items [Line Items]
1 year or less	1,019,610
More than 1 year but less than 3 years	359,381
3 years or more but less than 5 years	181,434
5 years or more	1,022,606
Total	2,583,031
Standby Letters of Credit [Member]
Contractual Obligations And Off Balance Sheet Items [Line Items]
1 year or less	72,593
More than 1 year but less than 3 years	5,389
3 years or more but less than 5 years	1,687
5 years or more	0
Total	$ 79,669

Other Comprehensive Income (L60

Other Comprehensive Income (Loss) - Tax Effects Allocated to Each Component of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Equity [Abstract]
Change in unrealized gain during period, before tax	$ 200	$ 29
Change in unrealized gain during period, tax	(42)	(10)
Change in unrealized gain during period, net of tax	158	19
Total securities available for sale, before tax	200	29
Total securities available for sale, tax	(42)	(10)
Total securities available for sale, net of tax	158	19
Total other comprehensive income	200	29
Total other comprehensive income, tax effect	(42)	(10)
Other comprehensive income, net of tax	$ 158	$ 19

Other Comprehensive Income (L61

Other Comprehensive Income (Loss) - Activity in Accumulated Other Comprehensive Income Associated with Securities Available for Sale, Net of Tax (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Beginning balance, accumulated other comprehensive income	$ (113)	$ 1,411
Other comprehensive income	158	19
Ending balance, accumulated other comprehensive income	45	1,430
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Beginning balance, accumulated other comprehensive income	(113)	1,411
Other comprehensive income	158	19
Ending balance, accumulated other comprehensive income	$ 45	$ 1,430