International Bancshares (IBOC) 10-K 25 Feb 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Feb. 22, 2021	Jun. 30, 2020
Document and Entity Information
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	0-09439
Entity Registrant Name	INTERNATIONAL BANCSHARES CORPORATION
Entity Incorporation, State or Country Code	TX
Entity Tax Identification Number	74-2157138
Entity Address, Address Line One	1200 San Bernardo Avenue
Entity Address, City or Town	Laredo
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	78042 - 1359
City Area Code	956
Local Phone Number	722-7611
Title of 12(b) Security	Common Stock, $1.00 par value
Trading Symbol	IBOC
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
ICFR Auditor Attestation Flag	true
Entity Public Float			$ 2,025,979
Entity Common Stock, Shares Outstanding		63,298,608
Entity Central Index Key	0000315709
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Statements of Cond

Consolidated Statements of Condition - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Assets
Cash and cash equivalents	$ 1,997,238,000	$ 256,820,000
Investment securities:
Held to maturity debt securities (Market value of $3,400 on December 31, 2020 and $2,400 on December 31, 2019)	3,400,000	2,400,000
Available for sale debt securities (Amortized cost of $3,054,289 on December 31, 2020 and $3,376,070 on December 31, 2019)	3,080,768,000	3,378,923,000
Equity securities with readily determinable fair values	6,202,000	6,095,000
Total investment securities	3,090,370,000	3,387,418,000
Loans	7,541,754,000	6,894,946,000
Less allowance for credit losses	(109,059,000)	(60,278,000)
Net loans	7,432,695,000	6,834,668,000
Bank premises and equipment, net	479,878,000	506,595,000
Accrued interest receivable	37,881,000	36,620,000
Other investments	254,413,000	318,427,000
Cash surrender value of life insurance policies	292,381,000	289,693,000
Goodwill	282,532,000	282,532,000
Other assets	162,079,000	200,121,000
Total assets	14,029,467,000	12,112,894,000
Deposits:
Demand-non-interest bearing	4,715,814,000	3,545,905,000
Savings and interest bearing demand	3,852,505,000	3,267,829,000
Time	2,153,541,000	2,012,300,000
Total deposits	10,721,860,000	8,826,034,000
Securities sold under repurchase agreements	428,148,000	236,536,000
Other borrowed funds	436,327,000	626,511,000
Junior subordinated deferrable interest debentures	134,642,000	134,642,000
Other liabilities	130,492,000	171,118,000
Total liabilities	11,851,469,000	9,994,841,000
Shareholders' equity:
Common shares of $1.00 par value. Authorized 275,000,000 shares; issued 96,240,977 shares on December 31, 2020 and 96,214,967 shares on December 31, 2019	96,241,000	96,215,000
Surplus	149,334,000	148,075,000
Retained earnings	2,289,626,000	2,200,568,000
Accumulated other comprehensive income	20,825,000	2,345,000
Total shareholders' equity before treasury stock	2,556,026,000	2,447,203,000
Less cost of shares in treasury, 32,961,289 shares on December 31, 2020 and 31,015,061 on December 31, 2019	(378,028,000)	(329,150,000)
Total shareholders' equity	2,177,998,000	2,118,053,000
Total liabilities and shareholders' equity	$ 14,029,467,000	$ 12,112,894,000

Consolidated Statements of Co_2

Consolidated Statements of Condition (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Held to maturity, Market value (in dollars)	$ 3,400	$ 2,400
Available for sale, Amortized cost (in dollars)	$ 3,054,289	$ 3,376,070
Common shares, par value (in dollars per share)	$ 1	$ 1
Common shares, Authorized shares	275,000,000	275,000,000
Common shares, issued shares	96,240,977	96,214,967
Treasury, shares	32,961,289	31,015,061

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest income:
Loans, including fees	$ 377,579,000	$ 413,611,000	$ 375,173,000
Investment securities:
Taxable	46,095,000	72,485,000	81,484,000
Tax-exempt	2,434,000	4,885,000	8,141,000
Other interest income	900,000	1,420,000	1,024,000
Total interest income	427,008,000	492,401,000	465,822,000
Interest expense:
Savings deposits	6,358,000	16,379,000	12,764,000
Time deposits	19,230,000	20,970,000	13,096,000
Securities sold under repurchase agreements	926,000	2,432,000	2,415,000
Other borrowings	8,773,000	12,413,000	17,404,000
Junior subordinated deferrable interest debentures	3,832,000	6,435,000	6,989,000
Total interest expense	39,119,000	58,629,000	52,668,000
Net interest income	387,889,000	433,772,000	413,154,000
Provision for credit losses	45,379,000	18,843,000	6,112,000
Net interest income after provision for credit losses	342,510,000	414,929,000	407,042,000
Other service charges, commissions and fees
Investment securities transactions, net	(5,000)	(12,000)	(141,000)
Other investments, net	4,920,000	5,985,000	19,897,000
Other income	26,873,000	17,523,000	18,367,000
Total non-interest income	150,579,000	154,826,000	165,042,000
Non-interest expense:
Employee compensation and benefits	130,039,000	145,929,000	138,532,000
Occupancy	24,909,000	28,635,000	29,097,000
Depreciation of bank premises and equipment	28,318,000	28,270,000	25,873,000
Professional fees	12,546,000	17,661,000	12,601,000
Deposit insurance assessments	1,870,000	1,416,000	3,742,000
Net expense, other real estate owned	9,808,000	6,377,000	4,413,000
Amortization of identified intangible assets	0	0	0
Advertising	4,284,000	7,748,000	7,695,000
Software and software maintenance	19,238,000	19,850,000	17,516,000
Other	50,319,000	53,915,000	60,032,000
Total non-interest expense	281,331,000	309,801,000	299,501,000
Income before income taxes	211,758,000	259,954,000	272,583,000
Provision for income taxes	44,439,000	54,850,000	56,652,000
Net income	$ 167,319,000	$ 205,104,000	$ 215,931,000
Basic earnings per common share:
Weighted average number of shares outstanding (in shares)	63,725,819	65,476,606	66,106,580
Net income (in dollars per share)	$ 2.63	$ 3.13	$ 3.27
Fully diluted earnings per common share:
Weighted average number of shares outstanding (in shares)	63,853,135	65,685,684	66,633,820
Net income (in dollars per share)	$ 2.62	$ 3.12	$ 3.24
Services charges on deposit accounts
Non-interest income:
Service charges on deposit accounts	$ 61,983,000	$ 72,502,000	$ 72,433,000
Other service charges, commissions and fees, Banking
Other service charges, commissions and fees
Banking	48,986,000	50,996,000	46,685,000
Other service charges, commissions and fees, Non-banking
Other service charges, commissions and fees
Non-banking	$ 7,822,000	$ 7,832,000	$ 7,801,000

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net income	$ 167,319	$ 205,104	$ 215,931
Other comprehensive income, net of tax:
Net unrealized holding gains (losses) on securities available for sale arising during period (net of tax effects of $4,911, $15,144, and $(7,004))	18,476	56,970	(26,348)
Reclassification adjustment for losses on securities available for sale included in net income (net of tax effects of $1, $3 and $30)	4	9	111
Other comprehensive income, net of tax	18,480	56,979	(26,237)
Comprehensive income	$ 185,799	$ 262,083	$ 189,694

Consolidated Statements of Co_3

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net unrealized holding (losses) gains on securities available for sale arising during period, tax effects	$ 4,911	$ 15,144	$ (7,004)
Reclassification adjustment for losses on securities available for sale included in net income, tax effects	$ 1	$ 3	$ 30

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]Adjustment	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]Adjustment	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Adjustment	Total
Balance at Dec. 31, 2017		$ 96,019	$ 171,816		$ 1,891,805		$ (28,397)	$ (292,263)		$ 1,838,980
Balance (in shares) at Dec. 31, 2017	96,019
Increase (decrease) in shareholders' equity
Net Income					215,931					215,931
Dividends:
Payable/Cash					(49,599)					(49,599)
Purchase of treasury stock								(19,042)		(19,042)
Exercise of stock options		85	1,437							1,522
Exercise of stock options (in shares)	85
Stock compensation expense recognized in earnings			1,035							1,035
Repurchase of outstanding warrant			(29,005)							(29,005)
Other comprehensive income, net of tax:
Net change in unrealized gains and losses on available for sale securities, net of reclassification adjustments							(20,240)			(20,240)
Balance at Dec. 31, 2018		96,104	145,283	$ 5,997	2,064,134	$ (5,997)	(54,634)	(311,305)		1,939,582
Balance (in shares) at Dec. 31, 2018	96,104
Increase (decrease) in shareholders' equity
Net Income					205,104					205,104
Dividends:
Payable/Cash					(68,670)					(68,670)
Purchase of treasury stock								(17,845)		(17,845)
Exercise of stock options		111	1,812							1,923
Exercise of stock options (in shares)	111
Stock compensation expense recognized in earnings			980							980
Other comprehensive income, net of tax:
Net change in unrealized gains and losses on available for sale securities, net of reclassification adjustments							56,979			56,979
Balance at Dec. 31, 2019		96,215	148,075		2,200,568		2,345	(329,150)		2,118,053
Balance (in shares) at Dec. 31, 2019	96,215
Increase (decrease) in shareholders' equity
Net Income					167,319					167,319
Dividends:
Payable/Cash					(69,928)					(69,928)
Purchase of treasury stock								(48,878)		(48,878)
Exercise of stock options		26	516							542
Exercise of stock options (in shares)	26
Stock compensation expense recognized in earnings			743							743
Other comprehensive income, net of tax:
Net change in unrealized gains and losses on available for sale securities, net of reclassification adjustments							18,480			18,480
Balance at Dec. 31, 2020		$ 96,241	$ 149,334	$ (8,333)	$ 2,289,626		$ 20,825	$ (378,028)	$ (8,333)	$ 2,177,998
Balance (in shares) at Dec. 31, 2020	96,241

Consolidated Statements of Sh_2

Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Payable/Cash Dividends (in dollars per share)	$ 1.10	$ 1.05	$ 0.75
Purchase of treasury stock (in shares)	1,946,228	468,918	520,918

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities:
Net income	$ 167,319	$ 205,104	$ 215,931
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit loss	45,379	18,843	6,112
Specific reserve, other real estate owned	1,539	322	3,071
Depreciation of bank premises and equipment	28,318	28,270	25,873
Gain on sale of bank premises and equipment	(40)	(237)	(1,456)
Gain on sale of other real estate owned	(892)	(1,470)	(1,465)
Accretion of investment securities discounts	(500)	(428)	(271)
Amortization of investment securities premiums	39,039	20,549	20,087
Investment securities transactions, net	5	12	141
Unrealized gain (loss) on equity securities with readily determinable fair values	(107)	(158)	388
Stock based compensation expense	743	980	1,035
Losses (earnings) from affiliates and other investments	74	(3,914)	(15,484)
Deferred income taxes	(3,122)	3,309	5,143
(Increase) decrease in accrued interest receivable	(1,261)	183	(2,347)
Decrease (increase) in other assets	42,571	8,043	(51,827)
(Decrease) increase in other liabilities	(13,932)	32,157	24,916
Net cash provided by operating activities	305,133	311,565	229,847
Investing activities:
Proceeds from maturities of securities	1,075		2,275
Proceeds from sales and calls of available for sale securities	42,350	94,585	38,175
Proceeds from sales of equity securities with readily determinable fair values			21,607
Purchases of available for sale securities	(1,819,814)	(893,301)	(47,346)
Principal collected on mortgage backed securities	2,058,626	882,479	675,304
Net increase in loans	(647,213)	(375,621)	(258,142)
Purchases of other investments	(44,447)	(52,795)	(43,418)
Distributions from other investments	64,860	44,919	3,668
Purchases of bank premises and equipment	(6,725)	(29,590)	(21,395)
Proceeds from sales of bank premises and equipment	904	1,861	4,533
Proceeds from sales of other real estate owned	6,679	9,405	4,179
Net cash (used in) provided by investing activities	(343,705)	(318,058)	379,440
Financing activities:
Net increase in non-interest bearing demand deposits	1,169,909	91,065	211,585
Net increase (decrease) in savings and interest bearing demand deposits	584,676	(408)	23,106
Net increase (decrease) in time deposits	141,241	38,832	(83,038)
Net increase (decrease) in securities sold under repurchase agreements	191,612	6,547	(123,816)
Net decrease in other borrowed funds	(190,184)	(79,154)	(489,560)
Redemption of long-term debt		(25,774)
Repurchase of outstanding common stock warrant			(29,005)
Purchase of treasury stock	(48,878)	(17,845)	(19,042)
Proceeds from stock transactions	542	1,923	1,522
Payments of cash dividends - common	(69,928)	(68,670)	(49,599)
Net cash used in financing activities	1,778,990	(53,484)	(557,847)
Increase (decrease) in cash and cash equivalents	1,740,418	(59,977)	51,440
Cash and cash equivalents at beginning of period	256,820	316,797	265,357
Cash and cash equivalents at end of period	1,997,238	256,820	316,797
Supplemental cash flow information:
Interest paid	41,975	56,728	50,623
Income taxes paid	34,826	44,089	40,565
Non-cash investing and financing activities:
Net transfers from loans to other real estate owned	4,526	22,015	$ 32,610
Establishment of lease liability and right-of-use asset		$ 6,171
Net transfers from bank premises and equipment to other assets	$ 4,260

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Summary of Significant Accounting Policies	(1) Summary of Significant Accounting Policies Our accounting and reporting policies conform to U.S. generally accepted accounting principles (“GAAP”) and to general practices within the banking industry. The following is a description of the more significant of those policies. Consolidation and Basis of Presentation Our consolidated financial statements include the accounts of the International Bancshares Corporation, its wholly-owned Subsidiary Banks and its wholly-owned non-bank subsidiaries, IBC Trading Company, Premier Tierra Holdings, Inc., IBC Charitable and Community Development Corporation, and IBC Capital Corporation. All significant inter-company balances and transactions have been eliminated in consolidation. We, through our Subsidiary Banks, are primarily engaged in the business of banking, including the acceptance of checking and savings deposits and the making of commercial, real estate, personal, home improvement, automobile and other installment and term loans. Our primary markets are north, south, central, and southeast Texas and the state of Oklahoma. Each of our Subsidiary Banks is very active in facilitating international trade along the United States border with Mexico and elsewhere. Although our loan portfolio is diversified, the ability of our debtors to honor their contracts is primarily dependent upon the economic conditions in our trade area. In addition, the investment portfolio is directly impacted by fluctuations in market interest rates. We are subject to the regulations of certain federal agencies as well as the Texas Department of Banking and the Oklahoma Department of Banking and undergo periodic examinations by those regulatory authorities. Such agencies may require certain standards or impose certain limitations based on their judgments or changes in law and regulations. We own one insurance-related subsidiary, IBC Insurance Agency, Inc., a wholly owned subsidiary of our Subsidiary Bank, International Bank of Commerce, Laredo. The insurance-related subsidiary does not conduct underwriting activities. The preparation of the consolidated financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the dates of the statement of condition and income and expenses for the periods. Actual results could differ significantly from those estimates. Material estimates that are particularly susceptible to significant changes in the near-term relate to the determination of ACL. Subsequent Events We have evaluated all events or transactions that occurred through the date we issued these financial statements. During this period, we did not have any material recognizable or non-recognizable subsequent events. Investment Securities We classify debt securities into one of these categories: held-to-maturity, available-for-sale, or trading. Such classifications are reassessed for appropriate classification at each reporting date. Securities that are intended and expected to be held until maturity are classified as “held-to-maturity” and are carried at amortized cost for financial statement reporting. Securities that are not positively expected to be held until maturity, but are intended to be held for an indefinite period of time are classified as “available-for-sale” or “trading” and are carried at their fair value. Unrealized holding gains and losses are included in net income for those securities classified as “trading”, while unrealized holding gains and losses related to those securities classified as “available-for-sale” are excluded from net income and reported net of tax as other comprehensive income and in shareholders’ equity as accumulated other comprehensive income (loss) until realized. In accordance with ASU 2016-13, which we adopted on January 1, 2020, available-for-sale and held-to-maturity debt securities in an unrealized loss position must be evaluated for the underlying cause of the loss. In the event that the deterioration in value is attributable to credit related reasons, then the amount of credit-related impairment would be recorded as a charge to our ACL with subsequent changes in the amount of impairment, up or down, also recorded through our ACL. The exception to this process will occur if we intend to sell an impaired available-for-sale debt security or if we will more likely than not be required to sell a credit impaired available-for-sale debt security prior to the value recovering to the security’s amortized cost. In those situations, the entire credit-related impairment amount would be required to be recognized in earnings. We have evaluated the debt securities classified as available-for-sale and held-to-maturity at December 31, 2020 and have determined that no debt securities in an unrealized loss position are arising from credit related reasons and have therefore not recorded any allowances for debt securities in our ACL for the period. Unrealized gains and losses related to equity securities with readily determinable fair values are included in net income. We did not maintain any trading securities during the three-year period ended December 31, 2020. Mortgage-backed securities held at December 31, 2020 and 2019 represent participating interests in pools of long-term first mortgage loans originated and serviced by the issuers of the securities. Mortgage-backed securities are either issued or guaranteed by the U.S. government or its agencies including Freddie Mac, Fannie Mae, Ginnie Mae or other non-government entities. Investments in residential mortgage-backed securities issued by Ginnie Mae are fully guaranteed by the U. S. government. Investments in residential mortgage-backed securities issued by Freddie Mac and Fannie Mae are not fully guaranteed by the U.S. government; however, we believe that the quality of the bonds is similar to other AAA rated bonds with limited credit risk, particularly given the placement of Fannie Mae and Freddie Mac into conservatorship by the federal government in 2008 and because securities issued by others that are collateralized by residential mortgage-backed securities issued by Fannie Mae or Freddie Mac are rated consistently as AAA rated securities. Market interest rate fluctuations can affect the prepayment speed of principal and the yield on the security. Premiums and discounts are amortized using the level yield or “interest method” over the terms of the securities. Declines in the fair value of held-to-maturity and available-for sale-securities below their cost that are deemed to be other than temporary are reflected in earnings as realized losses. In determining whether other-than-temporary impairment exists, management considers many factors, including (i) the length of time and the extent to which the fair value has been less than cost, (ii) the financial condition and near-term prospects of the issuer, and (iii) our intent to hold and our determination of whether we will more likely than not be required to sell the security prior to a recovery in fair value. If we determine that (i) we intend to sell the security or (ii) it is more likely than not that we will be required to sell the security before it’s anticipated recovery, the other-than-temporary impairment that is recognized in earnings is equal to the difference between the fair value of the security and our amortized cost of the security. If we determine that we (i) do not intend to sell the security and (ii) we will not be more likely than not required to sell the security before it’s anticipated recovery, the other-than-temporary impairment is segregated into its two components (i) the amount of impairment related to credit loss and (ii) the amount of impairment related to other factors. The difference between the present value of the cash flows expected to be collected and the amortized cost is the credit loss recognized through earnings and an adjustment to the cost basis of the security. The amount of impairment related to other factors is included in other comprehensive income (loss). Gains and losses on the sale of securities are recorded on the trade date and are determined using the specific identification method. Equity Securities Provision and Allowance for Credit Losses We adopted the provisions of Accounting Standards Update No. 2016-13 to ASC 326, “Financial Instruments – Credit Losses,” on January 1, 2020. ASU 2016-13 replaces the long-standing incurred loss model with an expected credit loss model that recognizes credit losses over the life of a financial asset. Expected credit losses capture historical information, current conditions, and reasonable and supportable forecasts of future conditions. The ACL is deducted from the amortized cost of an instrument to present the net amount expected to be collected on the financial asset. Our ACL primarily consists of the aggregate ACL estimates of our Subsidiary Banks. The estimates are established through charges to operations in the form of charges to provisions for credit loss expense. Loan losses or recoveries are charged or credited directly to the ACL. The ACL of each Subsidiary Bank is maintained at a level considered appropriate by management, based on estimated current expected credit losses in the current loan portfolio, including information about past events, current conditions and reasonable and supportable forecasts. Our management continually reviews the ACL of the Subsidiary Banks using the amounts determined from the estimates established on specific doubtful loans, the estimate established on quantitative historical loss percentages, and the estimate based on qualitative current conditions and reasonable and supportable two-year forecasted data. Our methodology reverts to the average lifetime loss-rate beyond the forecast period when we can no longer develop reasonable and supportable forecasts. Should any of the factors considered by management in evaluating the adequacy of the estimate for current expected credit losses change, our estimate of current expected credit losses could also change, which could affect the level of future credit loss expense. While the calculation of our ACL utilizes management’s best judgment and all information reasonably available, the adequacy of the ACL is dependent on a variety of factors beyond our control, including, among other things, the performance of the entire loan portfolio, the economy, government actions, changes in interest rates and the view of regulatory authorities towards loan classifications. We believe that the allowance for probable loan losses is adequate. The Subsidiary Banks charge-off that portion of any loan which management considers to represent a loss as well as that portion of any other loan which is classified as a “loss” by bank examiners. Commercial, financial and agricultural or real estate loans are generally considered by management to represent a loss, in whole or part, (i) when an exposure beyond any collateral coverage is apparent, (ii) when no further collection of the portion of the loan so exposed is anticipated based on actual results, (iii) when the credit enhancements, if any, are not adequate, and (iv) when the borrower’s financial condition would indicate so. Generally, unsecured consumer loans are charged-off when 90 days past due. Loans Loans are reported at the principal balance outstanding, net of unearned discounts. Interest income on loans is reported on an accrual basis. Loan fees and costs associated with originating the loans are accreted or amortized over the life of the loan using the interest method. We originate mortgage loans that may subsequently be sold to an unaffiliated third party. The loans are not securitized and if sold, are sold without recourse. Loans held for sale are carried at cost and the principal amount outstanding is not significant to the consolidated financial statements. Doubtful Loans Doubtful loans are those loans where it is probable that all amounts due according to contractual terms of the loan agreement will not be collected. Doubtful loans are measured based on (1) the present value of expected future cash flows discounted at the loan’s effective interest rate; (2) the loan’s observable market price; or (3) the fair value of the collateral if the loan is collateral dependent. Substantially all our doubtful loans are measured at the fair value of the collateral. In limited cases, we may use other methods to determine the level of impairment of a loan if such loan is not collateral dependent. Troubled Debt Restructured Loans Non-Accrual Loans The non-accrual loan policy of our Subsidiary Banks is to discontinue the accrual of interest on loans when management determines that it is probable that future interest accruals will be un-collectible. As it relates to consumer loans, management charges-off those loans when the loan is contractually 90 days past due. Under special circumstances, a consumer or non-consumer loan may be more than 90 days delinquent as to interest or principal and not be placed on non-accrual status. This situation generally results when a Subsidiary Bank has a borrower who is experiencing financial difficulties, but not to the extent that requires a restructuring of indebtedness. The majority of this category is composed of loans that are considered to be adequately secured and/or for which there are expected future payments. When a loan is placed on non-accrual status, any interest accrued, not paid is reversed and charged to operations against interest income. As it relates to non-consumer loans that are not 90 days past due, management will evaluate each of these loans to determine if placing the loan on non-accrual status is warranted. Interest income on non-accrual loans is recognized only to the extent payments are received or when, in management’s opinion, the debtor’s financial condition warrants reestablishment of interest accruals. Other Real Estate Owned and Repossessed Assets Other real estate owned is comprised of real estate acquired by foreclosure and deeds in lieu of foreclosure. Other real estate is carried at the lower of the recorded investment in the property or its fair value less estimated costs to sell such property (as determined by independent appraisal). Prior to foreclosure, the value of the underlying loan is written down to the fair value of the real estate to be acquired by a charge to the ACL, if necessary. Any subsequent write-downs are charged against other non-interest expense through a valuation allowance. Other real estate owned totaled approximately $60,487,300 and $71,103,000 at December 31, 2020 and 2019, respectively. Other real estate owned is included in other assets. Repossessed assets consist primarily of non-real estate assets acquired by foreclosure. Prior to foreclosure, the value of the underlying loan is written down to the fair value of the asset to be repossessed by a charge to the ACL, if necessary. Repossessed assets are included in other assets on the consolidated financial statements and totaled approximately $5,779,000 and $7,137,000 at December 31, 2020 and 2019, respectively. Bank Premises and Equipment Bank premises and equipment are stated at cost less accumulated depreciation. Depreciation is computed on straight-line and accelerated methods over the estimated useful lives of the assets. Repairs and maintenance are charged to operations as incurred and expenditures for renewals and betterments are capitalized. We primarily own all the property we occupy, with the exception of certain branches operating in grocery store or retail shopping centers and certain ATM locations, which are all under operating leases as classified under guidance prior to the issuance of ASU 2016-02, “Leases.” We adopted the guidance in ASU 2016-02 on January 1, 2019 and recorded a right of use asset and a lease liability other assets other liabilities Other Investments Other investments include equity investments in non-financial companies, as well as equity securities with no readily determinable fair market value. Equity investments are accounted for using the equity method of accounting. Equity securities with no readily determinable fair value are accounted for using the cost method. Revenue Recognition Income Taxes Deferred income tax assets and liabilities are determined using the asset and liability method. Under this method, the net deferred tax asset or liability is determined based on the tax effects of the differences between the book and tax basis of the various balance sheet assets and liabilities and gives current recognition to changes in tax rates and laws. We file a consolidated federal income tax return with our subsidiaries. Recognition of deferred tax assets is based on management’s assessment that the benefit related to certain temporary differences, tax operating loss carry forwards, and tax credits are more likely than not to be realized. A valuation allowance is recorded for the amount of the deferred tax items for which it is more likely than not that the tax benefits will not be realized. We evaluate uncertain tax positions at the end of each reporting period. We may recognize the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The tax benefit recognized in the financial statements from any such a position is measured based on the largest benefit that has a greater than fifty percent likelihood of being realized upon ultimate settlement. As of December 31, 2020 and 2019, respectively, after evaluating all uncertain tax positions, we have recorded no liability for unrecognized tax benefits at the end of the reporting period. We would recognize any interest accrued on unrecognized tax benefits as other interest expense and penalties as other non-interest expense. During the years ended December 31, 2020, 2019 and 2018, we recognized no interest expense or penalties related to uncertain tax positions. We file consolidated tax returns in the U.S. Federal jurisdiction and various state jurisdictions. We are no longer subject to U.S. federal or state income tax examinations by tax authorities for years before 2017. Stock Options Compensation expense for stock awards is based on the market price of the stock on the measurement date, which is generally the date of grant, and is recognized ratably over the service period of the award. The fair value of stock options granted was estimated using the Black-Sholes-Merton option-pricing model. This model was developed for use in estimating the fair value of publicly traded options that have no vesting restrictions and are fully transferable. Additionally, the model requires the input of highly subjective assumptions. Because our employee stock options have characteristics significantly different from those of publicly traded options, and because changes in the subjective input assumptions can materially affect the fair value estimate, in management’s opinion, the Black-Scholes-Merton option-pricing model does not necessarily provide a reliable single measure of the fair value of our stock options. Net Income Per Share Basic Earnings Per Share (“EPS”) is calculated by dividing net income by the weighted average number of common shares outstanding. The computation of diluted EPS assumes the issuance of common shares for all dilutive potential common shares outstanding during the reporting period. The dilutive effect of stock options is considered in earnings per share calculations, if dilutive, using the treasury stock method. Goodwill and Identified Intangible Assets Goodwill represents the excess of costs over fair value of assets of businesses acquired. Goodwill is tested for impairment at least annually or on an interim basis if an event triggering impairment may have occurred. As of October 1, 2020, after completing goodwill testing, we have determined that no goodwill impairment exists. Identified intangible assets are acquired assets that lack physical substance but can be distinguished from goodwill because of contractual or other legal rights or because the asset is capable of being sold or exchanged either on its own or in combination with a related contract, asset, or liability. Our identified intangible assets relate to core deposits and contract rights. As of December 31, 2020, we have determined that no impairment of identified intangibles exists. Identified intangible assets with definite useful lives are amortized on an accelerated basis over their estimated life. See Note 6—Goodwill and Other Intangible Assets. Impairment of Long-Lived Assets Long-lived assets, such as property, plant and equipment, and purchased intangibles subject to amortization, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying value of the asset to the estimated undiscounted future cash flows expected to be generated by the asset. If the carrying value of an asset exceeds its estimated future cash flows, an impairment charge is recognized by the amount by which the carrying value of the asset exceeds the fair value of the asset. Assets to be disposed of would be separately presented in the statement of condition and reported at the lower of the carrying value or fair value less costs to sell, and are no longer depreciated. The assets and liabilities of a disposed group classified as held for sale would be presented separately in the appropriate asset and liability sections of the statement of condition. Consolidated Statements of Cash Flows For purposes of the consolidated statements of cash flows, we consider all short-term investments with a maturity at date of purchase of three months or less to be cash equivalents. Also, we report transactions related to deposits and loans to customers on a net basis. Accounting for Transfers and Servicing of Financial Assets We account for transfers and servicing of financial assets and extinguishments of liabilities based on the application of a financial-components approach that focuses on control. After a transfer of financial assets, we recognize the financial and servicing assets we control and liabilities we have incurred, derecognize financial assets when control has been surrendered and derecognize liabilities when extinguished. We have retained mortgage servicing rights in connection with the sale of mortgage loans. Because we may not initially identify loans as originated for resale, all loans are initially treated as held for investment. The value of the mortgage servicing rights are reviewed periodically for impairment and are amortized in proportion to, and over the period of estimated net servicing income or net servicing losses. The value of the mortgage servicing rights is not significant to the consolidated statements of condition. Segments of an Enterprise and Related Information We operate as one segment. The operating information used by our chief executive officer for purposes of assessing performance and making operating decisions is the consolidated financial statements presented in this report. We have five active operating subsidiaries, namely, the Subsidiary Banks. We apply the provisions of ASC Topic 280, “Segment Reporting,” in determining our reportable segments and related disclosures. Comprehensive Income (Loss) Comprehensive income (loss) consists of net income and other comprehensive income (loss). Other comprehensive income (loss) includes unrealized gains and losses on securities available for sale. Advertising Advertising costs are expensed as incurred. Reclassifications Certain amounts in the prior year’s presentations have been reclassified to conform to the current presentation. These reclassifications had no effect on previously reported net income or shareholders’ equity. New Accounting Standards In February 2016, the FASB issued Accounting Standards Update No. 2016-02 to ASC 820, “Leases.” The update amends existing standards for accounting for leases by lessees, with accounting for leases by lessors remaining mainly unchanged from current guidance. The update requires that lessees recognize a lease liability and a right of use asset for all leases (with the exception of short-term leases) at the commencement date of the lease and disclose key information about leasing arrangements. The update is to be applied on a modified retrospective basis for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the consolidated financial statements. The update is effective for interim and annual periods beginning after December 15, 2018. In January 2018, the FASB issued a proposal that provides an additional transition method that would allow entities to not apply the guidance in the update in the comparative periods presented in the consolidated financial statements, but instead recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. On January 1, 2019, we adopted the provisions of ASU 2016-02, “Leases.” As part of our business model, we primarily own all property we occupy, with the exception of certain branches operating in grocery stores or shopping centers and certain ATM locations that were classified as operating leases under previous guidance. The adoption of the standard did not have a significant impact on our consolidated financial statements. As of the date of adoption, we recorded a right of use asset and a lease liability other assets other liabilities In June 2016, the FASB issued Accounting Standards Update No. 2016-13 to ASC 326, “Financial Instruments – Credit Losses.” The update amends existing standards for accounting for credit losses for financial assets. The update requires that the expected credit losses on the financial instruments held as of the end of the period being reported be measured based on historical experience, current conditions, and reasonable and supportable forecasts. The update also expands the required disclosures related to significant estimates and judgements used in estimating credit losses, as well as the credit quality and underwriting standards of an organization’s financial assets. The update also amended the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit deterioration. The impact of the adoption of the standard is to be recorded as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is adopted. The accounting standard was effective for us on January 1, 2020. The task force formed last year, which includes key members of the teams that work with the calculation of the allowance for probable loan losses plus members representing the corporate accounting and risk management areas, has worked with the implementation of the update and validation to complete our model/tool. Based on the composition of the portfolio at December 31, 2019 and after finalizing the methodology, the adoption of the update increased our allowance for probable loan losses (referred to as the ACL under ASU 2016-13), by approximately 17.2%, resulting in a cumulative-effect adjustment to retained earnings of approximately $8.3 million, net of tax. Please refer to Note 4 – Allowance for Credit Losses and the Critical Accounting Policies discussion in Management’s Discussion and Analysis. In January 2017, the FASB issued Accounting Standards Update No. 2017-04 to ASC 350, “Intangibles – Goodwill and Other.” The update amends existing guidance in evaluating goodwill for impairment. The update requires that an entity perform its annual or interim goodwill test by comparing the fair value of a reporting unit with its carrying amount, with any impairment charges being recognized as the difference between the fair value and carrying value. The update is intended to standardize the impairment test for all business entities and also reduce the complexity and cost of evaluating goodwill for impairment. The update is effective for any annual or interim goodwill impairment tests in fiscal years beginning after December 15, 2019. The adoption of the update is not expected to have a significant impact to our consolidated financial statements. In March 2017, the FASB issued Accounting Standards Update No. 2017-08 to ASC 310, “Receivables – Nonrefundable Fees and Other Costs.” The update amends existing guidance on the amortization period for certain callable debt securities held at a premium. The update shortens the amortization period of the premium to the earliest call date. The update is effective for fiscal years beginning after December 15, 2018. The update is to be applied on a modified retrospective basis through a cumulative-effect adjustment to retained earnings as of the beginning of the period of adoption. The adoption of the update did not have a significant impact to our consolidated financial statements. In February 2018, the FASB issued Accounting Standards Update No. 2018-02 to ASC 220, “Income Statement – Reporting Comprehensive Income.” The update amends current guidance surrounding the reclassification of certain tax effects from accumulated other comprehensive income. The update is being issued as a result of the 2017 Tax Cuts and Jobs Act and the related impact to comprehensive income as a result of the application of current guidance with respect to changes in tax rates. Under current guidance, entities must re-evaluate the carrying value of deferred tax assets and liabilities and adjust them for the tax effect of the rate change and record that change through earnings. The result is that the tax effects for items that normally would only be recognized in comprehensive income will be recognized through earnings and results in stranded tax effects in accumulated other comprehensive income (loss) for the impact of the rate change. The update will allow a reclassification from accumulated other comprehensive income (loss) to retained earnings for the stranded tax effects resulting from the 2017 Tax Cuts and Jobs Act. The update is effective for all entities for fiscal years beginning after December 31, 2018. We adopted the provisions of ASU 2018-02 to ASC 220 in the second quarter of 2018. We recorded a one-time reclassification of $5,997,000 between accumulated comprehensive income (loss) and retained earnings as a result of the adoption of the accounting standards update. In August 2018, the FASB issued Accounting Standards Update No. 2018-13 to ASC 820, “Fair Value Measurement.” The update amends the existing guidance surrounding the disclosure of certain fair value measurements. The update removes certain disclosures that are no longer considered cost beneficial, modifies and, in some instances clarifies, the specific requirements of certain disclosures and adds disclosure requirements that are identified relevant. The update is effective for fiscal years beginning after December 15, 2019. The adoption of the update is not expected to have a significant impact on our consolidated financial statements. In January 20201, the FASB issued Accounting Standards Update No. 2021-01, “Reference Rate Reform (Topic 848): Scope.” The update clarifies the applicability of the practical expedients and exceptions issued in ASU 2020-04 to derivative instruments that use an interest rate for margining, discounting or contract price alignment that is modified as a result of reference rate reform. The update is intended to capture the incremental consequences of the scope clarification and tailor the existing guidance to derivative instruments affected by the discounting transition. The update was effective as of the date of issuance and can be applied through December 31, 2022. We have not adopted the provisions of the update and to not anticipate that the adoption of the update will have a significant impact on our consolidated financial statements. ​

Investment Securities

Investment Securities	12 Months Ended
	Dec. 31, 2020
Investment Securities and Equity Securities with Readily Determinable Fair Values	(2) Investment Securities In accordance with ASU 2016-13, which we adopted on January 1, 2020, available-for-sale and held-to-maturity debt securities in an unrealized loss position must be evaluated for the underlying cause of the loss. In the event that the deterioration in value is attributable to credit related reasons, then the amount of credit-related impairment would be recorded as a charge to our ACL with subsequent changes in the amount of impairment, up or down, also recorded through our ACL. The exception to this process will occur if we intend to sell an impaired available-for-sale debt security or if we will more likely than not be required to sell a credit impaired available-for-sale debt security prior to the value recovering to the security’s amortized cost. In those situations, the entire credit-related impairment amount would be required to be recognized in earnings. We have evaluated the debt securities classified as available-for-sale and held-to-maturity at December 31, 2020 and have determined that no debt securities in an unrealized loss position are arising from credit related reasons and have therefore not recorded any allowances for debt securities in our ACL for the period. Unrealized gains and losses related to equity securities with readily determinable fair values are included in net income. The amortized cost and estimated fair value by type of investment security at December 31, 2020 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Held to Maturity ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ unrealized ​ unrealized ​ Estimated ​ Carrying ​ ​ ​ cost ​ gains ​ losses ​ fair value ​ value ​ ​ ​ (Dollars in Thousands) ​ Other securities $ 3,400 $ — $ — $ 3,400 $ 3,400 ​ Total investment securities ​ $ 3,400 ​ $ — ​ $ — ​ $ 3,400 ​ $ 3,400 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Available for Sale Debt Securities ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ unrealized ​ unrealized ​ Estimated ​ Carrying ​ ​ ​ cost ​ gains ​ losses ​ fair value ​ value (1) ​ ​ ​ (Dollars in Thousands) ​ Residential mortgage-backed securities $ 3,006,592 $ 32,701 $ (9,339) $ 3,029,954 $ 3,029,954 ​ Obligations of states and political subdivisions ​ 47,697 ​ 3,131 ​ (14) ​ 50,814 ​ 50,814 ​ Total investment securities ​ $ 3,054,289 ​ $ 35,832 ​ $ (9,353) ​ $ 3,080,768 ​ $ 3,080,768 ​ ​ (1) Included in the carrying value of residential mortgage- backed securities are $371,407 of mortgage-backed securities issued by Ginnie Mae and $2,658,547 of mortgage-backed securities issued by Fannie Mae and Freddie Mac The amortized cost and estimated fair value of investment securities at December 31, 2020, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to prepay obligations with or without prepayment penalties. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Held to Maturity ​ Available for Sale ​ ​ ​ Amortized ​ Estimated ​ Amortized ​ Estimated ​ ​ ​ Cost ​ fair value ​ Cost ​ fair value ​ ​ ​ (Dollars in Thousands) ​ Due in one year or less $ 1,200 $ 1,200 $ — $ — ​ Due after one year through five years ​ 2,200 ​ 2,200 ​ — ​ — ​ Due after five years through ten years ​ — ​ — ​ 355 ​ 356 ​ Due after ten years ​ — ​ — ​ 47,342 ​ 50,458 ​ Residential mortgage-backed securities ​ — ​ — ​ 3,006,592 ​ 3,029,954 ​ Total investment securities ​ $ 3,400 ​ $ 3,400 ​ $ 3,054,289 ​ $ 3,080,768 ​ ​ The amortized cost and estimated fair value by type of investment security at December 31, 2019 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Held to Maturity ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ unrealized ​ unrealized ​ Estimated ​ Carrying ​ ​ ​ cost ​ gains ​ losses ​ fair value ​ value ​ ​ ​ (Dollars in Thousands) ​ Other securities $ 2,400 $ — $ — $ 2,400 $ 2,400 ​ Total investment securities ​ $ 2,400 ​ $ — ​ $ — ​ $ 2,400 ​ $ 2,400 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Available for Sale ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ Estimated ​ ​ ​ ​ ​ ​ Amortized ​ unrealized ​ unrealized ​ fair ​ Carrying ​ ​ ​ cost ​ gains ​ losses ​ value ​ value (1) ​ ​ ​ (Dollars in Thousands) ​ Residential mortgage-backed securities $ 3,285,623 $ 16,534 $ (16,609) $ 3,285,548 $ 3,285,548 ​ Obligations of states and political subdivisions ​ 90,447 ​ 2,933 ​ (5) ​ 93,375 ​ 93,375 ​ Total investment securities ​ $ 3,376,070 ​ $ 19,467 ​ $ (16,614) ​ $ 3,378,923 ​ $ 3,378,923 ​ ​ (1) Included in the carrying value of residential mortgage- backed securities are $571,247 of mortgage-backed securities issued by Ginnie Mae, $2,714,301 of mortgage-backed securities issued by Fannie Mae and Freddie Mac Residential mortgage-backed securities are securities issued by Freddie Mac, Fannie Mae, Ginnie Mae or non-government entities. Investments in residential mortgage-backed securities issued by Ginnie Mae are fully guaranteed by the U.S. government. Investments in mortgage-backed securities issued by Freddie Mac and Fannie Mae are not fully guaranteed by the U.S. government; however, we believe that the quality of the bonds is similar to other AAA rated bonds with limited credit risk, particularly given the placement of Fannie Mae and Freddie Mac into conservatorship by the federal government in early September 2008 and because securities issued by others that are collateralized by residential mortgage-backed securities issued by Fannie Mae and Freddie Mac are rated consistently as AAA rated securities. The amortized cost and fair value of available for sale investment securities pledged to qualify for fiduciary powers, to secure public monies as required by law, repurchase agreements and short-term fixed borrowings was $1,220,400,000 and $1,224,268,000, respectively, at December 31, 2020. Proceeds from the sale and call of securities available-for-sale were $42,350,000, $94,585,000 and $59,782,000 during 2020, 2019 and 2018, respectively, which amounts included $0, $0 and $0 of mortgage-backed securities. Gross gains of $1,000, $3,000 and $3,000, and gross losses of $6,000, $15,000 and $144,000 were realized on the sales and calls in 2020, 2019 and 2018, respectively. Gross unrealized losses on investment securities and the fair value of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at December 31, 2020 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less than 12 months ​ 12 months or more ​ Total ​ ​ ​ ​ ​ ​ Unrealized ​ ​ ​ ​ Unrealized ​ ​ ​ ​ Unrealized ​ ​ ​ Fair Value ​ Losses ​ Fair Value ​ Losses ​ Fair Value ​ Losses ​ ​ ​ (Dollars in Thousands) ​ Available for sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential mortgage-backed securities $ 1,462,232 $ (9,339) $ — $ — $ 1,462,232 $ (9,339) ​ Obligations of states and political subdivisions ​ — ​ — ​ 757 ​ (14) ​ 757 ​ (14) ​ ​ ​ $ 1,462,232 ​ $ (9,339) ​ $ 757 ​ $ (14) ​ $ 1,462,989 ​ $ (9,353) ​ ​ Gross unrealized losses on investment securities and the fair value of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous loss position, at December 31, 2019 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less than 12 months ​ 12 months or more ​ Total ​ ​ ​ ​ ​ ​ Unrealized ​ ​ ​ ​ Unrealized ​ ​ ​ ​ Unrealized ​ ​ ​ Fair Value ​ Losses ​ Fair Value ​ Losses ​ Fair Value ​ Losses ​ ​ ​ (Dollars in Thousands) ​ Available for sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential mortgage-backed securities $ 523,031 $ (2,269) $ 1,448,109 $ (14,340) $ 1,971,140 $ (16,609) ​ Obligations of states and political subdivisions ​ 766 ​ (5) ​ — ​ — ​ 766 ​ (5) ​ ​ ​ $ 523,797 ​ $ (2,274) ​ $ 1,448,109 ​ $ (14,340) ​ $ 1,971,906 ​ $ (16,614) ​ ​ The unrealized losses on investments in residential mortgage-backed securities are primarily caused by changes in market interest rates. We have no intent to sell and more likely than not be required to sell before a market price recovery or maturity of the securities; therefore, it is our conclusion that the investments in residential mortgage-backed securities issued by Freddie Mac, Fannie Mae and Ginnie Mae are not considered other-than-temporarily impaired. ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, 2020 ​ ​ (Dollars in Thousands) ​ ​ ​ Net gains recognized during the period on equity securities $ ​ 107 Less: Net gains and (losses) recognized during the period on equity securities sold during the period ​ ​ — ​ ​ ​ ​ ​ Unrealized gains recognized during the reporting period on equity securities still held at the reporting date ​ $ ​ 107 ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, 2019 ​ ​ (Dollars in Thousands) ​ ​ ​ Net gains recognized during the period on equity securities $ ​ 158 Less: Net gains and (losses) recognized during the period on equity securities sold during the period ​ ​ — ​ ​ ​ ​ ​ Unrealized losses recognized during the reporting period on equity securities still held at the reporting date ​ $ ​ 158 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, 2018 ​ ​ (Dollars in Thousands) ​ ​ ​ Net losses recognized during the period on equity securities $ ​ (388) Less: Net gains and (losses) recognized during the period on equity securities sold during the period ​ ​ — ​ ​ ​ ​ ​ Unrealized losses recognized during the reporting period on equity securities still held at the reporting date ​ $ ​ (388) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Loans

Loans	12 Months Ended
	Dec. 31, 2020
Loans	(3) Loans A summary of loans, by loan type at December 31, 2020 and 2019 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ ​ ​ 2020 ​ 2019 ​ ​ ​ (Dollars in Thousands) ​ Commercial, financial and agricultural $ 4,516,288 $ 3,379,837 ​ Real estate - mortgage ​ 999,144 ​ 1,140,377 ​ Real estate - construction ​ 1,846,757 ​ 2,185,883 ​ Consumer ​ 40,595 ​ 47,800 ​ Foreign ​ 138,970 ​ 141,049 ​ Total loans ​ $ 7,541,754 ​ $ 6,894,946 ​ ​

Allowance for Credit Losses

Allowance for Credit Losses	12 Months Ended
	Dec. 31, 2020
Allowance for Credit Losses	(4) Allowance for Credit Losses We adopted the provisions of ASU 2016-13 on January 1, 2020 on a modified retrospective basis. Results and information regarding our ACL included in this Note are calculated and presented in accordance with that accounting standards update. Results and information prior to January 1, 2020 are calculated and presented in accordance with previously applicable U.S. GAAP. ​ ASU 2016-13 replaces the long-standing incurred loss model with an expected credit loss model that recognizes credit losses over the life of a financial asset. Expected credit losses capture historical information, current conditions, and reasonable and supportable forecasts of future conditions. The ACL is deducted from the amortized cost of an instrument to present the net amount expected to be collected on the financial asset. Our ACL primarily consists of the aggregate ACL estimates of our Subsidiary Banks. The estimates are established through charges to operations in the form of charges to provisions for credit loss expense. Loan losses or recoveries are charged or credited directly to the ACL. The ACL of each Subsidiary Bank is maintained at a level considered appropriate by management, based on estimated current expected credit losses in the current loan portfolio, including information about past events, current conditions and reasonable and supportable forecasts. ​ The estimation of the ACL is based on a loss-rate methodology that measures lifetime losses on loan pools that have similar risk characteristics. Loans that do not have similar risk characteristics are evaluated on an individual basis. The segmentation of the loan portfolio into pools requires a balancing process between capturing similar risk characteristics and containing sufficient loss history to provide meaningful results. Our segmentation starts at the general loan category with further sub-segmentation based on collateral types that may be of meaningful size and/or may contain sufficient differences in risk characteristics based on management’s judgement that would warrant further segmentation. The general loan categories along with primary risk characteristics used in our calculation are as follows: Commercial and industrial loans. Construction and land development loans. Commercial real estate loans. 1-4 family mortgages. ​ Consumer loans. ​ The loan pools are further broken down using a risk-based segmentation based on internal classifications for commercial loans and past due status for consumer mortgage loans. Non-mortgage consumer loans are evaluated as one segment. On a weekly basis, commercial loan past due reports are reviewed by the credit quality committee to determine if a loan has any potential problems and if a loan should be placed on our internal Watch List report. Additionally, our credit department reviews the majority of our loans for proper internal classification purposes regardless of whether they are past due and segregates any loans with potential problems for further review. The credit department will discuss the potential problem loans with the servicing loan officers to determine any relevant issues that were not discovered in the evaluation. Also, an analysis of loans that is provided through examinations by regulatory authorities is considered in the review process. After the above analysis is completed, we will determine if a loan should be placed on an internal Watch List report because of issues related to the analysis of the credit, credit documents, collateral and/or payment history. Our internal Watch List report is segregated into the following categories: (i) Pass, (ii) Economic Monitoring, (iii) Special Review, (iv) Watch List—Pass, or (v) Watch List—Substandard, and (vi) Watch List—Doubtful. The loans placed in the Special Review category and lower rated credits reflect our opinion that the loans reflect potential weakness which require monitoring on a more frequent basis. Credits in those categories are reviewed and discussed on a regular basis, no less frequently than quarterly, with the credit department and the lending staff to determine if a change in category is warranted. The loans placed in the Watch List—Pass category and lower rated credits reflect our opinion that the credit contains weaknesses which represent a greater degree of risk, which warrant “extra attention.” Credits in this category are reviewed and discussed on a regular basis with the credit department and the lending staff to determine if a change in category is warranted. The loans placed in the Watch List—Substandard category are considered to be potentially inadequately protected by the current sound worth and debt service capacity of the borrower or of any pledged collateral. These credit obligations, even if apparently protected by collateral value, have shown defined weaknesses related to adverse financial, managerial, economic, market or political conditions which may jeopardize repayment of principal and interest. Furthermore, there is the possibility that we may sustain some future loss if such weaknesses are not corrected. The loans placed in the Watch List—Doubtful category have shown defined weaknesses and it is likely, based on current information and events, that we will be unable to collect all principal and/or interest amounts contractually due. Watch List—Doubtful loans are placed on non-accrual when they are moved to that category. For the purposes of the ACL, in order to maintain segments with sufficient history for meaningful results, the credits in the Pass and Economic Monitoring categories are aggregated, the credits in the Special Review and Watch List—Pass credits are aggregated, and the credits in the Watch List—Substandard category remain in their own segment. For loans that are classified as Watch List—Doubtful, management evaluates these credits in accordance with ASC 310-10, “Receivables,” and, if deemed necessary, a specific reserve is allocated to the loan. The specific reserve allocated under ASC 310-10, is based on (i) the present value of expected future cash flows discounted at the loan’s effective interest rate; (ii) the loan’s observable market price; or (iii) net realizable value of the fair value of the collateral if the loan is collateral dependent. Substantially all of our loans evaluated as Watch List—Doubtful under ASC 310-10 are measured using the fair value of collateral method. In rare cases, we may use other methods to determine the specific reserve of a loan under ASC 310-10 if such loan is not collateral dependent. Within each collectively evaluated pool, the robustness of the lifetime historical loss-rate is evaluated and, if needed, is supplemented with peer loss rates through a model risk adjustment. Certain qualitative loss factors are then evaluated to incorporate management’s two-year reasonable and supportable forecast period followed by a reversion to the pool’s average lifetime loss-rate. Those qualitative loss factors are: (i) trends in portfolio volume and composition, (ii) volume and trends in classified loans, delinquencies, non-accruals and TDR’s, (iii) concentration risk, (iv) trends in underlying collateral value, (v) changes in policies, procedures, and strategies, and (vi) economic conditions. Qualitative factors also include potential losses stemming from operational risk factors arising from fraud, natural disasters, pandemics and geopolitical events. Should any of the factors considered by management in evaluating the adequacy of the ACL change, our estimate could also change, which could affect the level of future credit loss expense. We have elected to not measure an ACL for accrued interest receivable given our timely approach in identifying and writing off uncollectible accrued interest. An ACL for off-balance sheet exposure is derived from a projected usage rate of any unfunded commitment multiplied by the historical loss rate, plus model risk adjustment, if any, of the on-balance sheet loan pools. Our management continually reviews the ACL of the Subsidiary Banks using the amounts determined from the estimates established on specific doubtful loans, the estimate established on quantitative historical loss percentages, and the estimate based on qualitative current conditions and reasonable and supportable two-year forecasted data. Our methodology reverts to the average lifetime loss-rate beyond the forecast period when we can no longer develop reasonable and supportable forecasts. Should any of the factors considered by management in evaluating the adequacy of the estimate for current expected credit losses change, our estimate of current expected credit losses could also change, which could affect the level of future credit loss expense. While the calculation of our ACL utilizes management’s best judgment and all information reasonably available, the adequacy of the ACL is dependent on a variety of factors beyond our control, including, among other things, the performance of the entire loan portfolio, the economy, government actions, changes in interest rates and the view of regulatory authorities towards loan classifications. A summary of the changes in the allowance for probable loan losses by loan class is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ Domestic ​ ​ ​ ​ Foreign ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ real estate: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ other Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ construction & real estate: ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ land ​ farmland & ​ real estate: ​ Residential: ​ Residential: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ development ​ commercial ​ multifamily ​ first lien ​ junior lien ​ Consumer ​ Foreign ​ Total ​ ​ (Dollars in Thousands) ​ Balance at December 31, $ 11,145 ​ $ 18,152 ​ $ 16,533 ​ $ 1,786 ​ $ 3,762 ​ $ 7,535 ​ $ 542 ​ $ 823 ​ $ 60,278 ​ Adoption of ASU 2016-13 ​ ​ 4,247 ​ ​ 13,391 ​ ​ (4,292) ​ ​ (355) ​ ​ (1,580) ​ ​ (429) ​ ​ (225) ​ ​ (410) ​ ​ 10,347 ​ Losses charge to allowance ​ (8,936) ​ (19) ​ ​ (55) ​ — ​ (160) ​ (124) ​ (280) ​ — ​ (9,574) ​ Recoveries credited to allowance ​ 2,191 ​ 35 ​ 117 ​ — ​ 21 ​ 186 ​ 69 ​ 10 ​ 2,629 ​ Net losses charged to allowance ​ (6,745) ​ 16 ​ 62 ​ — ​ (139) ​ 62 ​ (211) ​ 10 ​ (6,945) ​ Provision (credit) charged to operations ​ 13,261 ​ ​ 6,053 ​ 17,697 ​ 3,620 ​ 1,831 ​ 2,402 ​ 185 ​ 330 ​ 45,379 ​ Balance at December 31, ​ $ 21,908 ​ $ 37,612 ​ $ 30,000 ​ $ 5,051 ​ $ 3,874 ​ $ 9,570 ​ $ 291 ​ $ 753 ​ $ 109,059 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ Domestic ​ ​ ​ ​ Foreign ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ real estate: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ other Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ construction & real estate: ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ land ​ farmland & ​ real estate: ​ Residential: ​ Residential: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial development ​ commercial ​ multifamily ​ first lien ​ junior lien ​ Consumer ​ Foreign ​ Total ​ ​ (Dollars in Thousands) ​ Balance at December 31, $ 12,596 ​ $ 15,123 ​ $ 19,353 ​ $ 1,808 ​ $ 3,467 ​ $ 7,719 ​ $ 447 ​ $ 871 $ 61,384 ​ Losses charge to allowance ​ (14,412) ​ (39) ​ (7,353) ​ — ​ (201) ​ (435) ​ (487) ​ (1) ​ (22,928) ​ Recoveries credited to allowance ​ 2,196 ​ 113 ​ 318 ​ — ​ 26 ​ 286 ​ 40 ​ — ​ 2,979 ​ Net losses charged to allowance ​ (12,216) ​ 74 ​ (7,035) ​ — ​ (175) ​ (149) ​ (447) ​ (1) ​ (19,949) ​ Provision (credit) charged to operations ​ 10,765 ​ 2,955 ​ 4,215 ​ (22) ​ 470 ​ (35) ​ 542 ​ (47) ​ 18,843 ​ Balance at December 31, ​ $ 11,145 ​ $ 18,152 ​ $ 16,533 ​ $ 1,786 ​ $ 3,762 ​ $ 7,535 ​ $ 542 ​ $ 823 ​ $ 60,278 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2018 ​ ​ Domestic ​ Foreign ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ real estate: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ other Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ construction & real estate: ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ land ​ farmland & ​ real estate: ​ Residential: ​ Residential: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial development ​ commercial ​ multifamily ​ first lien ​ junior lien ​ Consumer ​ Foreign ​ Total ​ (Dollars in Thousands) Balance at December 31, $ 27,905 $ 11,675 $ 16,663 $ 1,109 $ 2,950 $ 6,103 $ 440 $ 842 $ 67,687 ​ Losses charge to allowance ​ (14,220) ​ (1) ​ (70) ​ — ​ (122) ​ (347) ​ (362) ​ (3) ​ (15,125) ​ Recoveries credited to allowance ​ 1,981 ​ 25 ​ 246 ​ — ​ 36 ​ 369 ​ 43 ​ 10 ​ 2,710 ​ Net losses charged to allowance ​ (12,239) ​ 24 ​ 176 ​ — ​ (86) ​ 22 ​ (319) ​ 7 ​ (12,415) ​ Provision (credit) charged to operations ​ (3,070) ​ 3,424 ​ 2,514 ​ 699 ​ 603 ​ 1,594 ​ 326 ​ 22 ​ 6,112 ​ Balance at December 31, ​ $ 12,596 ​ $ 15,123 ​ $ 19,353 ​ $ 1,808 ​ $ 3,467 ​ $ 7,719 ​ $ 447 ​ $ 871 ​ $ 61,384 ​ ​ unexpectedly filing for bankruptcy and creating an exposure for potential loss since the operations of the dealerships were the source of repayment from the borrower. The relationship further deteriorated in the first quarter of 2019 after the sponsor of the court approved debtor in possession plan discontinued its role in the process and thus did not fulfill its obligation to assume full responsibility of the accrued and unpaid interest. Although the relationship is secured by real property (the dealerships’ real estate), the real property has specialized use, contributing to the potential exposure for probable loss. During the first quarter of 2019, in light of the circumstances and management’s evaluation of the relationship, the decision was made to place the relationship on impaired, non-accrual status and place a specific reserve on the relationship in the amount of $9.5 million. During the second quarter of 2019, management continued to evaluate the relationship and decided to foreclose on the underlying real estate collateral, resulting in a charge-off of approximately $9.5 million, reflected in the tables above as part of the Commercial and commercial real estate: farmland and commercial categories. The decrease in the provision for probable loan losses charged to expense for the years ended December 31, 2018 can be attributed to a decrease in the historical loss experience in the commercial category of the calculation. As discussed in prior periods, charge-offs increased from historical levels due to the deterioration of one relationship that was secured by multiple pieces of transportation equipment beginning in the fourth quarter of 2014. We use a three-year historical charge-off experience in the calculation, therefore, as those charge-offs were eliminated from the calculation, the allowance for probable loan losses (now ACL) was impacted. As fluctuations occur in historical loss factors, management evaluates the need to adjust the qualitative factors used in the calculation to properly reflect probable loan losses. The table below provides additional information on the balance of loans individually or collectively evaluated for impairment and their related allowance, by loan class: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ Loans Individually ​ Loans Collectively ​ ​ ​ Evaluated For ​ Evaluated For ​ ​ ​ Impairment ​ Impairment ​ ​ ​ Recorded ​ ​ ​ ​ Recorded ​ ​ ​ ​ ​ ​ Investment ​ Allowance ​ Investment ​ Allowance ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial $ 1,189 $ 209 $ 1,784,747 $ 21,699 ​ Commercial real estate: other construction & land development ​ 17,496 ​ 70 ​ 1,829,261 ​ 37,542 ​ Commercial real estate: farmland & commercial ​ 439 ​ — ​ 2,288,869 ​ 30,000 ​ Commercial real estate: multifamily ​ 134 ​ — ​ 440,910 ​ 5,051 ​ Residential: first lien ​ 151 ​ — ​ 404,968 ​ 3,874 ​ Residential: junior lien ​ 38 ​ — ​ 593,987 ​ 9,570 ​ Consumer ​ — ​ — ​ 40,595 ​ 291 ​ Foreign ​ — ​ — ​ 138,970 ​ 753 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 19,447 ​ $ 279 ​ $ 7,522,307 ​ $ 108,780 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ Loans Individually ​ Loans Collectively ​ ​ ​ Evaluated For ​ Evaluated For ​ ​ ​ Impairment ​ Impairment ​ ​ ​ Recorded ​ ​ ​ ​ Recorded ​ ​ ​ ​ ​ ​ Investment ​ Allowance ​ Investment ​ Allowance ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial $ 1,935 $ 249 $ 1,290,725 $ 10,895 ​ Commercial real estate: other construction & land development ​ 938 ​ 116 ​ 2,184,945 ​ 18,037 ​ Commercial real estate: farmland & commercial ​ 1,208 ​ — ​ 1,895,539 ​ 16,533 ​ Commercial real estate: multifamily ​ 165 ​ — ​ 190,265 ​ 1,786 ​ Residential: first lien ​ 6,278 ​ — ​ 427,623 ​ 3,762 ​ Residential: junior lien ​ 692 ​ — ​ 705,784 ​ 7,535 ​ Consumer ​ 1,195 ​ — ​ 46,605 ​ 542 ​ Foreign ​ 264 ​ — ​ 140,785 ​ 823 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 12,675 ​ $ 365 ​ $ 6,882,271 ​ $ 59,913 ​ ​ Loans accounted for on a non-accrual basis at December 31, 2020, 2019 and 2018 amounted to $19,822,000, $4,886,000 and $15,791,000, respectively. The increase in non-accrual commercial loans at December 31, 2020 compared to the same period of 2019 can be attributed to a relationship secured by commercial property. The decrease in non-accrual commercial loans at December 31, 2019 compared to the same period of 2018 can be attributed to a relationship secured by equipment and accounts receivable that has been upgraded to Watch-List Substandard. The effect of such non-accrual loans reduced interest income by approximately $694,000, $340,000 and $1,119,000 for the years ended December 31, 2020, 2019 and 2018, respectively. Amounts received on non-accruals are applied, for financial accounting purposes, first to principal and then to interest after all principal has been collected. Accruing loans contractually past due 90 days or more as to principal or interest payments at December 31, 2020, 2019 and 2018 amounted to approximately $8,238,000, $59,705,000 and $40,674,000, respectively. The increase at December 31, 2019 can be attributed to a relationship that is secured by multiple pieces of real property on which car dealerships are operated. The table below provides additional information on loans accounted for on a non-accrual basis by loan class: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ December 31, 2019 ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ ​ ​ ​ Commercial $ 1,189 $ 1,901 ​ Commercial real estate: other construction & land development ​ 17,496 ​ 938 ​ Commercial real estate: farmland & commercial ​ 439 ​ 1,208 ​ Commercial real estate: multifamily ​ 134 ​ 165 ​ Residential: first lien ​ 526 ​ 670 ​ Residential: junior lien ​ 38 ​ — ​ Consumer ​ — ​ 4 ​ Total non-accrual loans ​ $ 19,822 ​ $ 4,886 ​ ​ Doubtful loans are those loans where it is probable that all amounts due according to contractual terms of the loan agreement will not be collected. We have identified these loans through our normal loan review procedures. Doubtful loans are measured based on (i) the present value of expected future cash flows discounted at the loan’s effective interest rate; (ii) the loan’s observable market price; or (iii) the fair value of the collateral if the loan is collateral dependent. Substantially all of our doubtful loans are measured at the fair value of the collateral. In limited cases, we may use other methods to determine the level of impairment of a loan if such loan is not collateral dependent. The following tables detail key information regarding our doubtful loans (formerly “impaired loans” prior to the adoption of ASU 2016-13) by loan class at December 31, 2019, in accordance with ASC 310 prior to the adoption of ASU 2016-13: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ Unpaid ​ ​ ​ ​ Average ​ ​ ​ ​ ​ ​ Recorded ​ Principal ​ Related ​ Recorded ​ Interest ​ ​ ​ Investment ​ Balance ​ Allowance ​ Investment ​ Recognized ​ ​ ​ (Dollars in Thousands) Loans with Related Allowance ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ $ 510 ​ $ 516 ​ $ 249 ​ $ 514 ​ $ — ​ Commercial real estate: other construction & land development ​ ​ 126 ​ ​ 169 ​ ​ 116 ​ 131 ​ — ​ Total impaired loans with related allowance ​ $ 636 ​ $ 685 ​ $ 365 ​ $ 645 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ Unpaid ​ Average ​ ​ ​ ​ ​ Recorded ​ Principal ​ Recorded ​ Interest ​ ​ Investment ​ Balance ​ Investment ​ Recognized ​ ​ (Dollars in Thousands) Loans with No Related Allowance ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial $ 1,425 ​ $ 1,516 ​ $ 18,794 ​ $ 2 ​ Commercial real estate: other construction & land development ​ 812 ​ 1,133 ​ 1,737 ​ — ​ Commercial real estate: farmland & commercial ​ 1,208 ​ 1,841 ​ 22,357 ​ — ​ Commercial real estate: multifamily ​ 165 ​ 168 ​ 651 ​ — ​ Residential: first lien ​ 6,278 ​ 6,445 ​ 6,988 ​ 309 ​ Residential: junior lien ​ 692 ​ 692 ​ 1,023 ​ 42 ​ Consumer ​ 1,195 ​ 1,196 ​ 1,117 ​ — ​ Foreign ​ 264 ​ 264 ​ 278 ​ 12 ​ Total impaired loans with no related allowance ​ $ 12,039 ​ $ 13,255 ​ $ 52,945 ​ $ 365 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 December 31, 2019 ​ ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ ​ ​ ​ Commercial $ — $ 32 ​ Residential: first lien ​ ​ 4,078 ​ ​ 5,608 ​ Residential: junior lien ​ ​ 521 ​ ​ 692 ​ Consumer ​ ​ 989 ​ ​ 1,192 ​ Foreign ​ ​ 233 ​ ​ 264 ​ Total troubled debt restructuring ​ $ 5,821 ​ $ 7,788 ​ ​ We are actively working with our customers affected by the current economic crisis arising from COVID-19. We have been offering and are prepared to continue to offer assistance in accordance with current regulatory guidance. That includes continuously reaching out to our customers and, in some cases, offering short-term payment deferral plans. In accordance with the Coronavirus Aid, Relief and Economic Security (“CARES”) Act or interagency regulatory guidance, these short-term deferrals are not considered troubled debt restructurings. As of February 22, 2021, approximately $1,011,570,000 in loans with some degree of payment deferrals were in our system. Approximately 78% of the loans originally put into some sort of deferral program have resumed regular payments. The end of the deferral period on loans that are in some sort of payment deferral program will be throughout the first and second quarters of 2021 and we anticipate that approximately 13% of the loans still in a payment deferral program will request some degree of additional relief. The loans that may be requesting additional relief will include some customers in the industries that have been significantly impacted by the COVID-19 pandemic, including the hospitality sector, the oil and gas industry and retail developments. ​ The CARES Act was signed into law on March 27, 2020. It contains substantial tax and spending provisions intended to address the impact of the COVID-19 pandemic. The CARES Act includes the Paycheck Protection Program (“PPP”), originally a nearly $350 billion program designed to aid small businesses through federally guaranteed loans distributed through banks. These loans were originally intended to support eight weeks of payroll and certain other costs to help those businesses remain viable and allow their employees to pay their bills. Subsequently, on April 24, 2020, the Paycheck Protection Program and Health Care Enhancement Act (“CARES Part II”) was signed into law. CARES Part II provided an additional funding of $320 billion for the PPP program. Then, on June 5, 2020, the Paycheck Protection Program Flexibility Act (“PPPFA”) was signed into law. The PPPFA, among other things, extended the period of time that businesses could spend PPP loan proceeds on payroll and other eligible costs from eight weeks to the earlier of 24 weeks or December 31, 2020. On December 27, 2020, the Economic Aid to Hard-Hit Small Businesses, Nonprofits and Venues Act (the “Economic Aid Act”) was enacted, which among other things, reauthorized lending under the PPP to first-time borrowers and for second draws by certain borrowers who have previously received PPP loans. The Economic Aid Act made available an additional $147 billion for PPP loans requested by March 31, 2021. We have been active participants in helping our customers obtain PPP loans under all the PPP programs and as of February 22, 2021 have approximately 3,500 loans with an approximate value of $395,872,000 outstanding. The PPP loans are fully guaranteed by the U.S. government through the SBA. ​ The Subsidiary Banks charge-off that portion of any loan which management considers to represent a loss as well as that portion of any other loan which is classified as a “loss” by bank examiners. Commercial and industrial or real estate loans are generally considered by management to represent a loss, in whole or part, when an exposure beyond any collateral coverage is apparent and when no further collection of the loss portion is anticipated based on the borrower’s financial condition and general economic conditions in the borrower’s industry. Generally, unsecured consumer loans are charged-off when 90 days past due. ​ While management considers that it is generally able to identify borrowers with financial problems reasonably early and to monitor credit extended to such borrowers carefully, there is no precise method of predicting loan losses. The determination that a loan is likely to be uncollectible and that it should be wholly or partially charged-off as a loss is an exercise of judgment. Similarly, the determination of the adequacy of the ACL (formerly allowance for probable loan losses) can be made only on a subjective basis. It is the judgment of our management that the ACL at December 31, 2020 and December 31, 2019, was adequate to absorb probable losses from loans in the portfolio at that date. The following table presents information regarding the aging of past due loans by loan class: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 90 Days or ​ Total ​ ​ ​ ​ ​ ​ ​ ​ ​ 30 - 59 ​ 60 - 89 ​ 90 Days or ​ greater & ​ Past ​ ​ ​ ​ Total ​ ​ ​ Days ​ Days ​ Greater ​ still accruing ​ Due ​ Current ​ Portfolio ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial $ 1,931 $ 1,109 $ 563 $ 318 $ 3,603 $ 1,782,333 $ 1,785,936 ​ Commercial real estate: other construction & land development ​ 1,059 ​ 854 ​ 16,587 ​ — ​ 18,500 ​ 1,828,257 ​ 1,846,757 ​ Commercial real estate: farmland & commercial ​ 2,435 ​ 219 ​ 186 ​ 186 ​ 2,840 ​ 2,286,468 ​ 2,289,308 ​ Commercial real estate: multifamily ​ 126 ​ — ​ — ​ — ​ 126 ​ 440,918 ​ 441,044 ​ Residential: first lien ​ 2,399 ​ 926 ​ 6,165 ​ 5,890 ​ 9,490 ​ 395,629 ​ 405,119 ​ Residential: junior lien ​ 561 ​ 247 ​ 1,197 ​ 1,197 ​ 2,005 ​ 592,020 ​ 594,025 ​ Consumer ​ 318 ​ 71 ​ 79 ​ 79 ​ 468 ​ 40,127 ​ 40,595 ​ Foreign ​ 478 ​ 180 ​ 568 ​ 568 ​ 1,226 ​ 137,744 ​ 138,970 ​ Total past due loans ​ $ 9,307 ​ $ 3,606 ​ $ 25,345 ​ $ 8,238 ​ $ 38,258 ​ $ 7,503,496 ​ $ 7,541,754 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 90 Days or ​ Total ​ ​ ​ ​ ​ ​ ​ ​ ​ 30 - 59 ​ 60 - 89 ​ 90 Days or ​ greater & ​ Past ​ ​ ​ ​ Total ​ ​ ​ Days ​ Days ​ Greater ​ still accruing ​ Due ​ Current ​ Portfolio ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ $ 3,134 $ 626 $ 1,292 $ 421 $ 5,052 $ 1,287,608 $ 1,292,660 ​ Commercial real estate: other construction & land development ​ 509 ​ 55 ​ — ​ — ​ 564 ​ 2,185,319 ​ 2,185,883 ​ Commercial real estate: farmland & commercial ​ 8,058 ​ 2,031 ​ 54,928 ​ 54,878 ​ 65,017 ​ 1,831,730 ​ 1,896,747 ​ Commercial real estate: multifamily ​ 313 ​ — ​ 165 ​ — ​ 478 ​ 189,952 ​ 190,430 ​ Residential: first lien ​ 3,229 ​ 1,670 ​ 3,660 ​ 3,107 ​ 8,559 ​ 425,342 ​ 433,901 ​ Residential: junior lien ​ 1,112 ​ 477 ​ 1,200 ​ 1,200 ​ 2,789 ​ 703,687 ​ 706,476 ​ Consumer ​ 467 ​ 75 ​ 88 ​ 88 ​ 630 ​ 47,170 ​ 47,800 ​ Foreign ​ 1,347 ​ 3 ​ 11 ​ 11 ​ 1,361 ​ 139,688 ​ 141,049 ​ Total past due loans ​ $ 18,169 ​ $ 4,937 ​ $ 61,344 ​ $ 59,705 ​ $ 84,450 ​ $ 6,810,496 ​ $ 6,894,946 ​ ​ The decrease in commercial real estate: other construction & land development loans past due 90 days or greater at December 31, 2020 compared to December 31, 2019 can be primarily attributed to a relationship secured by real estate on which children’s learning centers are operated. Our internal classified report is segregated into the following categories: (i) “Special Review Credits,” (ii) “Watch List—Pass Credits,” or (iii) “Watch List—Substandard Credits.” The loans placed in the “Special Review Credits” category reflect our opinion that the loans reflect potential weakness which require monitoring on a more frequent basis. The “Special Review Credits” are reviewed and discussed on a regular basis with the credit department and the lending staff to determine if a change in category is warranted. The loans placed in the “Watch List—Pass Credits” category reflect our opinion that the credit contains weaknesses which represent a greater degree of risk, which warrant “extra attention.” The “Watch List—Pass Credits” are reviewed and discussed on a regular basis with the credit department and the lending staff to determine if a change in category is warranted. The loans placed in the “Watch List—Substandard Credits” classification are considered to be potentially inadequately protected by the current sound worth and debt service capacity of the borrower or of any pledged collateral. These credit obligations, even if apparently protected by collateral value, have shown defined weaknesses related to adverse financial, managerial, economic, market or political conditions which may jeopardize repayment of principal and interest. Furthermore, there is the possibility that we could sustain some future loss if such weaknesses are not corrected. A summary of the loan portfolio by credit quality indicator by loan class is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 2017 2016 Prior Total ​ ​ ​ (Dollars in Thousands) ​ Balance at December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 1,168,671 ​ $ 240,869 ​ $ 145,670 ​ $ 85,434 ​ $ 13,901 ​ $ 10,000 ​ $ 1,664,545 ​ Special Review ​ ​ 75,638 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 75,638 ​ Watch List - Pass ​ ​ 39,886 ​ ​ 11 ​ ​ — ​ ​ 3 ​ ​ — ​ ​ 17 ​ ​ 39,917 ​ Watch List - Substandard ​ ​ 3,360 ​ ​ 683 ​ ​ 289 ​ ​ — ​ ​ 315 ​ ​ — ​ ​ 4,647 ​ Watch List - Doubtful ​ ​ 777 ​ ​ 161 ​ ​ 92 ​ ​ 159 ​ ​ — ​ ​ — ​ ​ 1,189 ​ Total Commercial ​ $ 1,288,332 ​ $ 241,724 ​ $ 146,051 ​ $ 85,596 ​ $ 14,216 ​ $ 10,017 ​ $ 1,785,936 ​ Commercial real estate: other construction & land development ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 773,165 ​ $ 576,707 ​ $ 320,308 ​ $ 78,174 ​ $ 10,534 ​ $ 3,343 ​ $ 1,762,231 ​ Special Review ​ ​ 20,828 ​ ​ 21,650 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 42,478 ​ Watch List - Pass ​ ​ 23,101 ​ ​ 1,451 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 24,552 ​ Watch List - Doubtful ​ ​ 16,702 ​ ​ 794 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 17,496 ​ Total Commercial real estate: other construction & land development ​ $ 833,796 ​ $ 600,602 ​ $ 320,308 ​ $ 78,174 ​ $ 10,534 ​ $ 3,343 ​ $ 1,846,757 ​ Commercial real estate: farmland & commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 884,070 ​ $ 373,993 ​ $ 386,268 ​ $ 189,639 ​ $ 202,500 ​ $ 116,729 ​ $ 2,153,199 ​ Special Review ​ ​ 3,041 ​ ​ — ​ ​ 4,758 ​ ​ 177 ​ ​ 3,218 ​ ​ — ​ ​ 11,194 ​ Watch List - Pass ​ ​ 61,637 ​ ​ 942 ​ ​ 277 ​ ​ 80 ​ ​ — ​ ​ — ​ ​ 62,936 ​ Watch List - Substandard ​ ​ 53,809 ​ ​ 4,986 ​ ​ — ​ ​ 2,269 ​ ​ 475 ​ ​ 1 ​ ​ 61,540 ​ Watch List - Doubtful ​ ​ — ​ ​ 202 ​ ​ — ​ ​ — ​ ​ — ​ ​ 237 ​ ​ 439 ​ Total Commercial real estate: farmland & commercial ​ $ 1,002,557 ​ $ 380,123 ​ $ 391,303 ​ $ 192,165 ​ $ 206,193 ​ $ 116,967 ​ $ 2,289,308 ​ Commercial real estate: multifamily ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 74,577 ​ $ 208,356 ​ $ 82,818 ​ $ 64,110 ​ $ 6,801 ​ $ 4,248 ​ $ 440,910 ​ Watch List - Doubtful ​ ​ 134 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 134 ​ Total Commercial real estate: multifamily ​ $ 74,711 ​ $ 208,356 ​ $ 82,818 ​ $ 64,110 ​ $ 6,801 ​ $ 4,248 ​ $ 441,044 ​ Residential: first lien ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 81,004 ​ $ 62,165 ​ $ 72,299 ​ $ 54,593 ​ $ 29,250 ​ $ 105,463 ​ $ 404,774 ​ Watc

Bank Premises and Equipment

Bank Premises and Equipment	12 Months Ended
	Dec. 31, 2020
Bank Premises and Equipment	(5) Bank Premises and Equipment A summary of bank premises and equipment, by asset classification, at December 31, 2020 and 2019 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Estimated ​ ​ ​ ​ ​ ​ ​ ​ useful lives ​ 2020 ​ 2019 ​ ​ ​ ​ ​ ​ ​ (Dollars in Thousands) Bank buildings and improvements 5 - 39 years $ 577,656 $ 573,257 ​ Furniture, equipment and vehicles 1 - 20 years ​ 311,313 ​ 313,880 ​ Land ​ ​ ​ ​ ​ ​ 117,848 ​ 118,099 ​ Less: accumulated depreciation ​ ​ ​ ​ ​ ​ (526,939) ​ (498,641) ​ Bank premises and equipment, net ​ ​ ​ ​ ​ ​ $ 479,878 ​ $ 506,595 ​ ​

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2020
Goodwill and Other Intangible Assets	(6) Goodwill and Other Intangible Assets The majority of our identified intangibles are in the form of amortizable core deposit premium. A small portion of the fully amortized identified intangibles represent identified intangibles in the acquisition of the rights to the insurance agency contracts of InsCorp, Inc., acquired in 2008. Information on our identified intangible assets follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Carrying ​ Accumulated ​ ​ ​ ​ ​ Amount ​ Amortization ​ Net ​ ​ (Dollars in Thousands) December 31, 2020: ​ ​ ​ ​ Core deposit premium ​ $ 58,675 ​ $ 58,675 ​ $ — ​ Identified intangible (contract rights) ​ 2,022 ​ 2,022 ​ — ​ Total identified intangibles ​ $ 60,697 ​ $ 60,697 ​ $ — ​ December 31, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Core deposit premium ​ $ 58,675 ​ $ 58,675 ​ $ — ​ Identified intangible (contract rights) ​ 2,022 ​ 2,022 ​ — ​ Total identified intangibles ​ $ 60,697 ​ $ 60,697 ​ $ — ​ ​ Amortization expense of intangible assets was $0, $0 and $0 for the years ended December 31, 2020, 2019 and 2018. There were no changes in the carrying amount of goodwill for the years ended December 31, 2020 and 2019.

Deposits

Deposits	12 Months Ended
	Dec. 31, 2020
Deposits	(7) Deposits Deposits as of December 31, 2020 and 2019 and related interest expense for the years ended December 31, 2020, 2019 and 2018 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 ​ ​ (Dollars in Thousands) Deposits: ​ ​ ​ Demand - non-interest bearing ​ ​ ​ ​ ​ ​ ​ Domestic ​ $ 3,781,277 ​ $ 2,815,835 ​ Foreign ​ 934,537 ​ 730,070 ​ Total demand non-interest bearing ​ 4,715,814 ​ 3,545,905 ​ Savings and interest bearing demand ​ ​ ​ ​ ​ ​ ​ Domestic ​ 2,919,314 ​ 2,477,668 ​ Foreign ​ 933,191 ​ 790,161 ​ Total savings and interest bearing demand ​ 3,852,505 ​ 3,267,829 ​ Time, certificates of deposit $100,000 or more ​ ​ ​ ​ ​ ​ ​ Domestic ​ 797,692 ​ 636,005 ​ Foreign ​ 822,387 ​ 827,031 ​ Less than $100,000 ​ ​ ​ ​ ​ ​ ​ Domestic ​ 291,473 ​ 302,620 ​ Foreign ​ 241,989 ​ 246,644 ​ Total time, certificates of deposit ​ 2,153,541 ​ 2,012,300 ​ Total deposits ​ $ 10,721,860 ​ $ 8,826,034 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 ​ 2018 ​ ​ (Dollars in Thousands) Interest expense: ​ ​ ​ ​ Savings and interest bearing demand ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic $ 5,098 ​ $ 13,462 ​ $ 11,029 ​ Foreign ​ 1,260 ​ 2,917 ​ 1,735 ​ Total savings and interest bearing demand ​ 6,358 ​ 16,379 ​ 12,764 ​ Time, certificates of deposit $100,000 or more ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ 8,827 ​ 7,804 ​ 4,741 ​ Foreign ​ 7,536 ​ 9,407 ​ 5,798 ​ Less than $100,000 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ 1,781 ​ 2,232 ​ 1,589 ​ Foreign ​ 1,086 ​ 1,527 ​ 968 ​ Total time, certificates of deposit ​ 19,230 ​ 20,970 ​ 13,096 ​ Total interest expense on deposits ​ $ 25,588 ​ $ 37,349 ​ $ 25,860 ​ ​ Scheduled maturities of time deposits as of December 31, 2020 were as follows: ​ ​ ​ ​ ​ ​ ​ Total ​ ​ (in thousands) 2021 ​ $ 1,971,433 ​ 2022 ​ 141,388 ​ 2023 ​ 28,781 ​ 2024 ​ 11,205 ​ 2025 ​ 681 ​ Thereafter ​ 53 ​ Total ​ $ 2,153,541 ​ ​ Scheduled maturities of time deposits in amounts of $100,000 or more at December 31, 2020, were as follows: ​ ​ ​ ​ ​ ​ ​ Total ​ ​ (in thousands) Due within 3 months or less $ 606,807 Due after 3 months and within 6 months ​ 385,859 Due after 6 months and within 12 months ​ 498,626 Due after 12 months ​ 129,792 ​ ​ $ 1,621,084 ​ ​ Time deposits that meet or exceed the FDIC insurance limit of $250,000 at December 31, 2020 and December 31, 2019 were $1,085,404 and $929,860, in thousands, respectively.

Securities Sold Under Repurchas

Securities Sold Under Repurchase Agreements	12 Months Ended
	Dec. 31, 2020
Securities Sold Under Repurchase Agreements	(8) Securities Sold Under Repurchase Agreements Our Subsidiary Banks have entered into repurchase agreements with individual customers of the Subsidiary Banks. The purchasers have agreed to resell to the Subsidiary Banks identical securities upon the maturities of the agreements. Securities sold under repurchase agreements were mortgage-backed securities and averaged $335,392,000 and $267,439,000 during 2020 and 2019, respectively, and the maximum amount outstanding at any month end during 2020 and 2019 was $428,148,000 and $299,827,000 respectively. Further information related to repurchase agreements at December 31, 2020 and 2019 is set forth in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Collateral Securities ​ Repurchase Borrowing ​ ​ Book Value of ​ Fair Value of ​ Balance of ​ Weighted Average ​ ​ Securities Sold ​ Securities Sold ​ Liability ​ Interest Rate ​ ​ (Dollars in Thousands) December 31, 2020 term: ​ ​ ​ ​ Overnight agreements ​ $ 506,020 ​ $ 507,164 ​ $ 416,757 0.13 % 1 to 29 days ​ — ​ — ​ — — ​ 30 to 90 days ​ — ​ — ​ — — ​ Over 90 days ​ 11,684 ​ 11,641 ​ 11,391 0.43 ​ Total ​ $ 517,704 ​ $ 518,805 ​ $ 428,148 0.14 % December 31, 2019 term: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Overnight agreements ​ $ 317,107 ​ $ 318,397 ​ $ 225,243 0.87 % 1 to 29 days ​ — ​ — ​ — — ​ 30 to 90 days ​ — ​ — ​ — — ​ Over 90 days ​ 11,564 ​ 11,529 ​ 11,293 1.28 ​ Total ​ $ 328,671 ​ $ 329,926 ​ $ 236,536 0.89 % ​ The book value and fair value of securities sold includes the entire book value and fair value of securities partially or fully pledged under repurchase agreements.

Other Borrowed Funds

Other Borrowed Funds	12 Months Ended
	Dec. 31, 2020
Other Borrowed Funds	(9) Other Borrowed Funds Other borrowed funds include Federal Home Loan Bank borrowings, which may be short and long-term fixed borrowings issued by the Federal Home Loan Bank of Dallas and the Federal Home Loan Bank of Topeka at the market price offered at the time of funding. These borrowings are secured by mortgage-backed investment securities and a portion of our loan portfolio. Further information regarding our other borrowed funds at December 31, 2020 and 2019 is set forth in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ 2020 ​ 2019 ​ ​ (Dollars in Thousands) Federal Home Loan Bank advances—short-term ​ ​ ​ Balance at year end ​ $ — ​ $ 190,000 ​ Rate on balance outstanding at year end ​ — % 1.48 % Average daily balance ​ $ 110,776 ​ $ 190,431 ​ Average rate ​ 1.19 % 2.60 % Maximum amount outstanding at any month end ​ $ 292,000 ​ $ 371,775 ​ Federal Home Loan Bank advances—long-term (1) ​ ​ ​ ​ ​ ​ ​ Balance at year end ​ $ 436,327 ​ $ 436,511 ​ Rate on balance outstanding at year end ​ 1.73 % 1.73 % Average daily balance ​ $ 436,411 ​ $ 436,593 ​ Average rate ​ 1.71 % 1.71 % Maximum amount outstanding at any month end ​ $ 436,495 ​ $ 436,675 ​ ​ (1) Long-term advances at December 31, 2020 and December 31, 2019 consisted of both amortizing and non-amortizing advances. The non-amortizing advances mature in the following increments: $75,000,000 in July 2028, $100,000,000 in March 2033 and $250,000,000 in August 2033 and are callable by the FHLB on a quarterly basis. Two amortizing advances are outstanding at December 31, 2020 in the amounts of $3,091,000 and $8,236,000 and mature in December 2033 and November 2033, respectively. The amortization on the amortizing long-term advances totals approximately $189,000 , $194,000 , $199,000 , $204,000 and $210,000 for the years ending December 31, 2021, December 31, 2022, December 31, 2023, December 31, 2024 and December 31, 2025, respectively.

Junior Subordinated Deferrable

Junior Subordinated Deferrable Interest Debentures	12 Months Ended
	Dec. 31, 2020
Junior Subordinated Interest Deferrable Debentures	(10) Junior Subordinated Deferrable Interest Debentures We have formed five statutory business trusts under the laws of the State of Delaware for the purpose of issuing trust preferred securities. These statutory business trusts (the “Trusts”) have each issued Capital and Common Securities and invested the proceeds thereof in an equivalent amount of junior subordinated debentures (the “Debentures”) we issued. As of December 31, 2020 and December 31, 2019, the principal amount of debentures outstanding totaled $134,642,000. The Debentures are subordinated and junior in right of payment to all our present and future senior indebtedness (as defined in the respective indentures) and are pari passu For financial reporting purposes, the Trusts are treated as investments and not consolidated in the consolidated financial statements. Although the Capital Securities issued by each of the Trusts are not included as a component of shareholders’ equity on the consolidated statement of condition, the Capital Securities are treated as capital for regulatory purposes. Specifically, under applicable regulatory guidelines, the Capital Securities issued by the Trusts qualify as Tier 1 capital up to a maximum of 25% of Tier 1 capital on an aggregate basis. Any amount that exceeds the 25% threshold would qualify as Tier 2 capital. At December 31, 2020 and December 31, 2019, the total $134,642,000 of the Capital Securities outstanding qualified as Tier 1 capital. The following table illustrates key information about each of the Debentures and their interest rates at December 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Junior ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Subordinated ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferrable ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest ​ Repricing ​ Interest ​ Interest ​ ​ ​ Optional ​ ​ ​ Debentures ​ Frequency ​ Rate ​ Rate Index(1) ​ Maturity Date ​ Redemption Date (1) ​ ​ ​ (Dollars in Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Trust VIII ​ $ 25,774 Quarterly 3.29 % LIBOR + 3.05 October 2033 October 2008 ​ Trust IX ​ 41,238 Quarterly 1.85 % LIBOR + 1.62 October 2036 October 2011 ​ Trust X ​ 21,021 Quarterly 1.86 % LIBOR + 1.65 February 2037 February 2012 ​ Trust XI ​ 25,990 Quarterly 1.85 % LIBOR + 1.62 July 2037 July 2012 ​ Trust XII ​ 20,619 Quarterly 1.68 % LIBOR + 1.45 September 2037 September 2012 ​ ​ ​ $ 134,642 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) The Capital Securities may be redeemed in whole or in part on any interest payment date after the Optional Redemption Date.

Earnings per Share ("EPS")

Earnings per Share ("EPS")	12 Months Ended
	Dec. 31, 2020
Earnings per Share ("EPS")	(11) Earnings per Share (“EPS”) Basic EPS is calculated by dividing net income by the weighted average number of common shares outstanding. The computation of diluted EPS assumes the issuance of common shares for all dilutive potential common shares outstanding during the reporting period. The calculation of the basic EPS and the diluted EPS for the years ended December 31, 2020, 2019, and 2018 is set forth in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net Income ​ Shares ​ Per Share ​ ​ (Numerator) ​ (Denominator) ​ Amount ​ ​ (Dollars in Thousands, ​ ​ Except Per Share Amounts) December 31, 2020: ​ ​ ​ Basic EPS ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income available to common shareholders ​ $ 167,319 63,725,819 ​ $ 2.63 ​ Potential dilutive common shares and warrants ​ — 127,316 ​ ​ ​ ​ Diluted EPS ​ $ 167,319 63,853,135 ​ $ 2.62 ​ December 31, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic EPS ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income available to common shareholders ​ $ 205,104 65,476,606 ​ $ 3.13 ​ Potential dilutive common shares and warrants ​ — 209,078 ​ ​ ​ ​ Diluted EPS ​ $ 205,104 65,685,684 ​ $ 3.12 ​ December 31, 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic EPS ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income available to common shareholders ​ $ 215,931 66,106,580 ​ $ 3.27 ​ Potential dilutive common shares ​ — 527,240 ​ ​ ​ ​ Diluted EPS ​ $ 215,931 66,633,820 ​ $ 3.24 ​ ​

Employees' Profit Sharing Plan

Employees' Profit Sharing Plan	12 Months Ended
	Dec. 31, 2020
Employees' Profit Sharing Plan	(12) Employees’ Profit Sharing Plan We have a deferred profit sharing plan for full-time employees with a minimum of one year of continuous employment. Our annual contribution to the plan is based on a percentage, as determined by our Board of Directors, of income before income taxes, as defined, for the year. Allocation of the contribution among officers and employees’ accounts is based on length of service and amount of salary earned. Profit sharing costs of $4,000,000, $4,200,000 and $3,850,000 were charged to income for the years ended December 31, 2020, 2019, and 2018, respectively.

International Operations

International Operations	12 Months Ended
	Dec. 31, 2020
International Operations	(13) International Operations We provide international banking services for our customers through our Subsidiary Banks. Neither we nor our Subsidiary Banks have facilities located outside the United States. International operations are distinguished from domestic operations based upon the domicile of the customer. Because the resources we employ are common to both international and domestic operations, it is not practical to determine net income generated exclusively from international activities. A summary of assets attributable to international operations at December 31, 2020 and 2019 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 ​ ​ (Dollars in Thousands) Loans: ​ ​ ​ Commercial ​ $ 90,177 ​ $ 88,979 ​ Others ​ 48,793 ​ 52,070 ​ ​ ​ 138,970 ​ 141,049 ​ Less allowance for probable loan losses ​ (753) ​ (823) ​ Net loans ​ $ 138,217 ​ $ 140,226 ​ Accrued interest receivable ​ $ 605 ​ $ 743 ​ ​ At December 31, 2020, we had $118,722,000 in outstanding standby and commercial letters of credit to facilitate trade activities. Revenues directly attributable to international operations were approximately $4,676,000, $5,445,000 and $5,412,000 for the years ended December 31, 2020, 2019 and 2018, respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Taxes	(14) Income Taxes We file a consolidated U.S. Federal and State income tax return. The current and deferred portions of net income tax expense included in the consolidated statements of income are presented below for the years ended December 31: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 ​ 2018 ​ ​ (Dollars in Thousands) Current ​ ​ ​ ​ U.S. ​ $ 43,794 ​ $ 48,559 ​ $ 48,144 ​ State ​ 3,709 ​ 2,944 ​ 3,370 ​ Foreign ​ 58 ​ 38 ​ (5) ​ Total current taxes ​ 47,561 ​ 51,541 ​ 51,509 ​ Deferred ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. ​ (2,733) ​ 2,979 ​ 5,130 ​ State ​ (389) ​ 330 ​ 13 ​ Total deferred taxes ​ (3,122) ​ 3,309 ​ 5,143 ​ Total income taxes ​ $ 44,439 ​ $ 54,850 ​ $ 56,652 ​ ​ Total income tax expense differs from the amount computed by applying the U.S. Federal income tax rate of 21%for 2020, 2019 and 2018 to income before income taxes. The reasons for the differences for the years ended December 31 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 ​ 2018 ​ ​ (Dollars in Thousands) Computed expected tax expense $ 45,218 $ 55,086 $ 57,831 ​ Change in taxes resulting from: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tax-exempt interest income ​ (2,709) ​ (2,550) ​ (3,101) ​ State tax, net of federal income taxes, tax credit and refunds ​ 2,622 ​ 2,587 ​ 2,673 ​ Resolution of IRS exam ​ ​ ​ — ​ — ​ Other investment income ​ (2,205) ​ (1,480) ​ (1,561) ​ Deferred tax adjustment due to federal tax rate change ​ ​ ​ ​ ​ — ​ ​ (1,618) ​ Net investment in low income housing investments ​ ​ 1,990 ​ ​ 623 ​ ​ 2,518 ​ Other ​ (477) ​ 584 ​ (90) ​ Actual tax expense ​ $ 44,439 ​ $ 54,850 ​ $ 56,652 ​ ​ The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, 2020 and 2019 are reflected below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 ​ ​ (Dollars in Thousands) Deferred tax assets: ​ ​ ​ Loans receivable, principally due to the allowance for probable loan losses ​ $ 21,921 ​ $ 12,050 ​ Other real estate owned ​ 1,183 ​ 2,501 ​ Impairment charges on available-for-sale securities ​ — ​ 1,054 ​ Accrued expenses ​ 81 ​ 98 ​ Other ​ 5,649 ​ 6,019 ​ Total deferred tax assets ​ 28,834 ​ 21,722 ​ Deferred tax liabilities: ​ ​ ​ ​ ​ ​ ​ Bank premises and equipment, principally due to differences on depreciation ​ (12,350) ​ (12,478) ​ Net unrealized gains on available for sale investment securities ​ ​ (5,679) ​ ​ (508) ​ Impairment charges on available-for-sale securities ​ ​ (19) ​ ​ — ​ Identified intangible assets and goodwill ​ (13,807) ​ (13,649) ​ Other ​ (20,551) ​ (18,849) ​ Total deferred tax liabilities ​ (52,406) ​ (45,484) ​ Net deferred tax liability ​ $ (23,572) ​ $ (23,762) ​ ​ The net deferred tax liability of $23,572,000 at December 31, 2020 and $23,762,000 at December 31, 2019 is included in other liabilities in the consolidated statements of condition.

Stock Options

Stock Options	12 Months Ended
	Dec. 31, 2020
Stock Options	(15) Stock Options On April 5, 2012, the Board of Directors adopted the 2012 International Bancshares Corporation Stock Option Plan (the “2012 Plan”). There are 800,000 shares available for stock option grants under the 2012 Plan. Under the 2012 Plan, both qualified incentive stock options (“ISOs”) and non-qualified stock options (“NQSOs”) may be granted. Options granted may be exercisable for a period of up to 10 years from the date of grant, excluding ISOs granted to 10% shareholders, which may be exercisable for a period of up to only five years. As of December 31, 2020, 10,102 shares were available for future grants under the 2012 Plan. The fair value of each option award granted under the plan is estimated on the date of grant using a Black-Scholes-Merton option valuation model that uses the assumptions noted in the following table. Expected volatility is based on the historical volatility of the price of our stock. We use historical data to estimate the expected dividend yield and employee termination rates within the valuation model. The expected term of options is derived from historical exercise behavior. The risk-free rate for periods within the contractual life of the option is based on the U.S. Treasury yield curve in effect at the time of grant. ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 Expected Life (Years) 7.00 ​ 7.00 ​ Dividend yield 6.04 % 2.93 % Interest rate 0.74 % 1.97 % Volatility 29.04 % 26.97 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ A summary of option activity under the stock option plans for the twelve months ended December 31, 2020 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ Weighted ​ average ​ ​ ​ ​ ​ ​ ​ ​ average ​ remaining ​ Aggregate ​ ​ ​ Number of ​ exercise ​ contractual ​ intrinsic ​ ​ ​ options ​ price ​ term (years) ​ value ($) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (in Thousands) ​ Options outstanding at December 31, 2019 658,588 ​ $ 27.55 ​ ​ ​ ​ ​ ​ Plus: Options granted 35,000 ​ 18.79 ​ ​ ​ ​ ​ ​ Less: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options exercised 26,010 ​ 20.87 ​ ​ ​ ​ ​ ​ Options expired — ​ — ​ ​ ​ ​ ​ ​ Options forfeited 16,451 ​ 31.94 ​ ​ ​ ​ ​ ​ Options outstanding at December 31, 2020 651,127 ​ 27.24 5.05 ​ $ 6,817 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options fully vested and exercisable at December 31, 2020 409,782 ​ $ 22.98 3.61 ​ $ 5,953 ​ ​ Stock-based compensation expense included in the consolidated statements of income for the years ended December 31, 2020, 2019 and 2018 was approximately $743,000, $980,000 and $1,035,000, respectively. As of December 31, 2020, there was approximately $1,254,000 of total unrecognized stock-based compensation cost related to non-vested options granted under our plans that will be recognized over a weighted average period of 1.7 years. Other information pertaining to option activity during the twelve months ended December 31, 2020, 2019 and 2018 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Twelve Months Ended December 31, ​ ​ 2020 ​ 2019 ​ 2018 Weighted average grant date fair value of stock options granted $ 2.46 $ 7.38 $ 11.78 ​ Total fair value of stock options vested ​ $ 1,218,000 ​ $ 1,333,000 ​ $ 1,077,000 ​ Total intrinsic value of stock options exercised ​ $ 356,000 ​ $ 2,373,000 ​ $ 2,045,000 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Long Term Restricted Stock Unit

Long Term Restricted Stock Units	12 Months Ended
	Dec. 31, 2020
Long Term Restricted Stock Units	(16) Long Term Restricted Stock Units As a former participant in the Troubled Asset Relief Program Capital Purchase Program (the “CPP”) we were subject to certain compensation restrictions, including a prohibition on the payment or accrual of any bonuses to certain officers and employees except for awards of CPP-compliant long- term restricted stock and stock units. On December 18, 2009, our board of directors (the “Board”) adopted the 2009 International Bancshares Corporation Long-Term Restricted Stock Unit Plan (the “Plan”) to give us additional flexibility in the compensation of our officers, employees, consultants and advisors in compliance with all applicable laws and restrictions. The Plan authorizes us to issue Restricted Stock Units (“RSUs”) to our officers, employees, consultants and advisors. On December 18, 2009, pursuant to the Plan, the Board adopted resolutions creating the Long-Term Restricted Stock Unit Plan Committee to administer the Plan. RSUs issued under the Plan are not equity and are payable only in cash. The Plan provides for both the issuance of CPP-compliant long-term RSUs as well as RSUs that are not CPP-compliant. No grants have been made under the Plan since December 2012 and there are currently no outstanding grants under the Plan. The plan was terminated on August 6, 2019.

Commitments, Contingent Liabili

Commitments, Contingent Liabilities and Other Tax Matters	12 Months Ended
	Dec. 31, 2020
Commitments, Contingent Liabilities and Other Tax Matters	(17) Commitments, Contingent Liabilities and Other Matters On March 15, 2020, the FRB announced that it had reduced regulatory reserve requirements to zero percent effective on March 26, 2020. Cash of approximately $125,764,000 December 31, 2019 was maintained to satisfy regulatory reserve requirements. We are involved in various legal proceedings that are in various stages of litigation. We have determined, based on discussions with our counsel that any material loss in such actions, individually or in the aggregate, is remote or the damages sought, even if fully recovered, would not be considered material to our consolidated statements of condition and related statements of income, comprehensive income, shareholders’ equity and cash flows. However, many of these matters are in various stages of proceedings and further developments could cause management to revise its assessment of these matters.

Transactions with Related Parti

Transactions with Related Parties	12 Months Ended
	Dec. 31, 2020
Transactions with Related Parties	(18) Transactions with Related Parties In the ordinary course of business, the Subsidiary Banks make loans to our directors and executive officers, including their affiliates, families and companies in which they are principal owners. In the opinion of management, these loans are made on substantially the same terms, including interest rates and collateral, as those prevailing at the time for comparable transactions with other persons and do not involve more than normal risk of collectability or present other unfavorable features. The aggregate amounts receivable from such related parties amounted to approximately $30,398,000 and $37,605,000 at December 31, 2020 and 2019, respectively. ​

Financial Instruments with Off-

Financial Instruments with Off-Statement of Condition Risk and Concentrations of Credit Risk	12 Months Ended
	Dec. 31, 2020
Financial Instruments with Off-Statement of Condition Risk and Concentrations of Credit Risk	(19) Financial Instruments with Off-Statement of Condition Risk and Concentrations of Credit Risk In the normal course of business, the Subsidiary Banks are party to financial instruments with off-statement of condition risk to meet the financing needs of their customers. These financial instruments include commitments to their customers. These financial instruments involve, to varying degrees, elements of credit risk in excess of the amounts recognized in the consolidated statement of condition. The contract amounts of these instruments reflect the extent of involvement the Subsidiary Banks have in particular classes of financial instruments. At December 31, 2020, the following financial amounts of instruments, whose contract amounts represent credit risks, were outstanding: ​ ​ ​ ​ ​ Commitments to extend credit $ 2,354,010,000 Credit card lines ​ 13,579,000 Standby letters of credit ​ 118,381,000 Commercial letters of credit ​ 341,000 ​ We enter into a standby letter of credit to guarantee performance of a customer to a third party. These guarantees are primarily issued to support public and private borrowing arrangements. The credit risk involved is represented by the contractual amounts of those instruments. Under the standby letters of credit, we are required to make payments to the beneficiary of the letters of credit upon request by the beneficiary so long as all performance criteria have been met. At December 31, 2020, the maximum potential amount of future payments is approximately $118,381,000. At December 31, 2020, the fair value of these guarantees is not significant. Unsecured letters of credit totaled approximately $39,487,000 and $49,965,000 at December 31, 2020 and 2019, respectively. We enter into commercial letters of credit on behalf of our customers which authorize a third party to draw drafts upon us up to a stipulated amount and with specific terms and conditions. A commercial letter of credit is a conditional commitment on our part to provide payment on drafts drawn in accordance with the terms of the commercial letter of credit. The Subsidiary Banks’ exposure to credit loss in the event of nonperformance by the other party to the above financial instruments is represented by the contractual amounts of the instruments. The Subsidiary Banks use the same credit policies in making commitments and conditional obligations as they do for on-statement of condition instruments. The Subsidiary Banks control the credit risk of these transactions through credit approvals, limits and monitoring procedures. Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates normally less than one year or other termination clauses and may require the payment of a fee. Since many of the commitments are expected to expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. The Subsidiary Banks evaluate each customer’s credit-worthiness on a case-by-case basis. The amount of collateral obtained, if deemed necessary by the Subsidiary Banks upon extension of credit, is based on management’s credit evaluation of the customer. Collateral held varies, but may include residential and commercial real estate, bank certificates of deposit, accounts receivable and inventory. The Subsidiary Banks make commercial, real estate and consumer loans to customers principally located in South, Central and Southeast Texas and the State of Oklahoma. Although the loan portfolio is diversified, a substantial portion of its debtors’ ability to honor their contracts is dependent upon the economic conditions in these areas, especially in the real estate and commercial business sectors.

Capital Requirements

Capital Requirements	12 Months Ended
	Dec. 31, 2020
Capital Requirements	(20) Capital Requirements Bank regulatory agencies limit the amount of dividends, which the Subsidiary Banks can pay, without obtaining prior approval from such agencies. At December 31, 2020, the Subsidiary Banks could pay dividends of up to $948,000,000 without prior regulatory approval and without adversely affecting their “well-capitalized” status under regulatory capital rules in effect at December 31, 2020. In addition to legal requirements, regulatory authorities also consider the adequacy of the Subsidiary Banks’ total capital in relation to their deposits and other factors. These capital adequacy considerations also limit amounts available for payment of dividends. We historically have not allowed any Subsidiary Bank to pay dividends in such a manner as to impair its capital adequacy. We and the Subsidiary Banks are subject to various regulatory capital requirements administered by the federal banking agencies. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material effect on our consolidated financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, we must meet specific capital guidelines that involve quantitative measures of our assets, liabilities, and certain off-statement of condition items as calculated under regulatory accounting practices. Our capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weightings, and other factors. Current quantitative measures established by regulation to ensure capital adequacy require us to maintain minimum amounts and ratios (set forth in the table on the following page) of Total and Tier 1 capital to risk-weighted assets and of Tier 1 capital to average assets. Management believes, as of December 31, 2020, that we met all capital adequacy requirements to which we are subject. On November 21, 2017, the OCC, the Federal Reserve and the FDIC finalized a proposed rule that extends the current treatment under the regulatory capital rules for certain regulatory capital deductions and risk weights and certain minority interest requirements, as they apply to banking organizations that are not subject to the advanced approaches capital rules. Effective January 1, 2018, the rule also paused the full transition to the Basel III treatment of mortgage servicing assets, certain deferred tax assets, investments in the capital of unconsolidated financial institutions and minority interests. The agencies are also considering whether to make adjustments to the capital rules in response to CECL (the FASB Standard relating to current expected credit loss) and its potential impact on regulatory capital. On December 7, 2017, the Basel Committee on Banking Supervision unveiled the latest round of its regulatory capital framework, commonly called “Basel IV.” The framework makes changes to the capital framework first introduced as “Basel III” in 2010. The committee targeted 2022-2027 as the timeframe for implementation by regulators in individual countries, including the U.S. federal bank regulatory agencies (after notice and comment). On May 24, 2018, the EGRRCPA was enacted and, among other things, it includes a simplified capital rule change which effectively exempts banks with assets of less than $10 billion that exceed the “community bank leverage ratio,” from all risk-based capital requirements, including Basel III and its predecessors. The federal banking agencies must establish the “community bank leverage ratio” (a ratio of tangible equity to average consolidated assets) between 8% and 10% before community banks can begin to take advantage of this regulatory relief provision. Some of the Subsidiary Banks, with assets of less than $10 billion, may qualify for this exemption. Additionally, under the EGRRCPA, qualified bank holding companies with assets of up to $3 billion (currently $1 billion) will be eligible for the Federal Reserve’s Small Bank Holding Company Policy Statement, which eases limitations on the issuance of debt by holding companies. On August 28, 2018, the Federal Reserve issued an interim final rule expanding the applicability of its Small Bank Holding Company Policy Statement. While holding companies that meet the conditions of the policy statement are excluded from consolidated capital requirements, their depository institutions continue to be subject to minimum capital requirements. Finally, for banks that continue to be subject to the risk-based capital rules of Basel III (e.g., 150%), certain commercial real estate loans that were formally classified as high volatility commercial real estate 31 (“HVCRE”) will not be subject to heightened risk weights if they meet certain criteria. Also, while acquisition, development, and construction (“ADC”) loans will generally be subject to heightened risk weights, certain exceptions will apply. On September 18, 2018, the federal banking agencies issued a proposed rule modifying the agencies’ capital rules for HVCRE. ​ Our actual capital amounts and ratios for 2020 under current guidelines are presented in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For Capital Adequacy ​ To Be Well-Capitalized ​ ​ ​ ​ ​ ​ ​ Purposes ​ Under Prompt Corrective ​ ​ Actual ​ Phase In Schedule ​ Action Provisions ​ ​ Amount ​ Ratio ​ Amount ​ Ratio ​ Amount ​ Ratio ​ ​ ​ ​ ​ ​ ​ (greater than ​ (greater than ​ (greater than ​ (greater than ​ ​ ​ ​ ​ ​ ​ or equal to) ​ or equal to) ​ or equal to) ​ or equal to) ​ ​ (Dollars in Thousands) As of December 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Common Equity Tier 1 (to Risk Weighted Assets): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 1,874,641 19.05 % $ 688,678 7.000 % ​ N/A N/A ​ International Bank of Commerce, Laredo ​ 1,295,437 18.19 ​ 498,492 7.000 ​ $ 462,885 6.50 % International Bank of Commerce, Oklahoma ​ ​ 207,339 ​ 17.45 ​ ​ 83,150 ​ 7.000 ​ ​ 77,211 ​ 6.50 ​ International Bank of Commerce, Brownsville ​ 189,575 22.18 ​ 59,843 7.000 ​ 55,569 6.50 ​ International Bank of Commerce, Zapata ​ 71,369 34.51 ​ 14,476 7.000 ​ 13,442 6.50 ​ Commerce Bank ​ 93,426 35.64 ​ 18,347 7.000 ​ 17,037 6.50 ​ Total Capital (to Risk Weighted Assets): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 2,105,360 21.40 % $ 1,033,017 10.500 % ​ N/A N/A ​ International Bank of Commerce, Laredo ​ 1,380,685 19.39 ​ 747,737 10.500 ​ $ 712,131 10.00 % International Bank of Commerce, Oklahoma ​ ​ 218,657 ​ 18.41 ​ ​ 124,725 ​ 10.500 ​ ​ 118,786 ​ 10.00 ​ International Bank of Commerce, Brownsville ​ 200,269 23.43 ​ 89,765 10.500 ​ 85,490 10.00 ​ International Bank of Commerce, Zapata ​ 73,510 35.55 ​ 21,714 10.500 ​ 20,680 10.00 ​ Commerce Bank ​ 96,240 36.72 ​ 27,521 10.500 ​ 26,210 10.00 ​ Tier 1 Capital (to Risk Weighted Assets): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 1,992,403 20.25 % $ 836,252 8.500 % N/A N/A ​ International Bank of Commerce, Laredo ​ 1,295,437 18.19 ​ 605,311 8.500 ​ $ 569,705 8.00 % International Bank of Commerce, Oklahoma ​ ​ 207,339 ​ 17.45 ​ ​ 100,968 ​ 8.500 ​ ​ 95,029 ​ 8.00 ​ International Bank of Commerce, Brownsville ​ 189,575 22.18 ​ 72,667 8.500 ​ 68,392 8.00 ​ International Bank of Commerce, Zapata ​ 71,369 34.51 ​ 17,578 8.500 ​ 16,544 8.00 ​ Commerce Bank ​ 93,426 35.64 ​ 22,279 8.500 ​ 20,968 8.00 ​ Tier 1 Capital (to Average Assets): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 1,992,403 14.92 % $ 534,228 4.00 % $ N/A N/A ​ International Bank of Commerce, Laredo ​ 1,295,437 13.11 ​ 395,289 4.00 ​ 494,112 5.00 % International Bank of Commerce, Oklahoma ​ ​ 207,339 ​ 12.98 ​ ​ 63,879 ​ 4.00 ​ ​ 79,848 ​ 5.00 ​ International Bank of Commerce, Brownsville ​ 189,575 14.55 ​ 52,101 4.00 ​ 65,127 5.00 ​ International Bank of Commerce, Zapata ​ 71,369 16.52 ​ 17,277 4.00 ​ 21,596 5.00 ​ Commerce Bank ​ 93,426 16.69 ​ 22,394 4.00 ​ 27,993 5.00 ​ ​ ​ Our actual capital amounts and ratios for 2019 are also presented in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ To Be Well-Capitalized ​ ​ ​ ​ ​ ​ ​ For Capital Adequacy ​ ​ Under Prompt Corrective ​ ​ Actual ​ Purposes ​ ​ Action Provisions ​ ​ Amount ​ Ratio ​ Amount ​ Ratio ​ ​ Amount Ratio ​ ​ ​ ​ ​ ​ ​ (greater than ​ (greater than ​ (greater than ​ (greater than ​ ​ ​ ​ ​ ​ ​ or equal to) ​ or equal to) ​ or equal to) ​ or equal to) ​ ​ (Dollars in Thousands) As of December 31, 2019: ​ ​ ​ ​ Common Equity Tier 1 (to Risk Weighted Assets): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 1,833,174 18.58 % $ 690,746 7.000 % ​ N/A N/A ​ International Bank of Commerce, Laredo ​ 1,268,078 18.23 ​ 486,950 7.000 ​ $ 452,168 6.50 % International Bank of Commerce, Oklahoma ​ ​ 201,202 ​ 16.91 ​ ​ 83,303 ​ 7.000 ​ ​ 77,353 ​ 6.50 ​ International Bank of Commerce, Brownsville ​ 185,112 22.70 ​ 57,084 7.000 ​ 53,006 6.50 ​ International Bank of Commerce, Zapata ​ 72,402 36.46 ​ 13,902 7.000 ​ 12,909 6.50 ​ Commerce Bank ​ 91,239 34.83 ​ 18,336 7.000 ​ 17,026 6.50 ​ Total Capital (to Risk Weighted Assets): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 2,018,488 20.46 % $ 1,036,118 10.500 % ​ N/A N/A % International Bank of Commerce, Laredo ​ 1,315,453 18.91 ​ 730,425 10.500 ​ $ 695,643 10.00 ​ International Bank of Commerce, Oklahoma ​ ​ 206,807 ​ 17.38 ​ ​ 124,955 ​ 10.500 ​ ​ 119,004 ​ 10.00 ​ International Bank of Commerce, Brownsville ​ 192,417 23.60 ​ 85,626 10.500 ​ 81,548 10.00 ​ International Bank of Commerce, Zapata ​ 74,737 37.63 ​ 20,853 10.500 ​ 19,860 10.00 ​ Commerce Bank ​ 93,396 35.65 ​ 27,504 10.500 ​ 26,195 10.00 ​ Tier 1 Capital (to Risk Weighted Assets): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ % Consolidated ​ $ 1,953,711 19.80 % $ 838,762 8.500 % N/A N/A ​ International Bank of Commerce, Laredo ​ 1,268,078 18.23 ​ 591,296 8.500 ​ $ 556,514 8.00 ​ International Bank of Commerce, Oklahoma ​ ​ 201,202 ​ 16.91 ​ ​ 101,154 ​ 8.500 ​ ​ 95,203 ​ 8.00 ​ International Bank of Commerce, Brownsville ​ 185,112 22.70 ​ 69,316 8.500 ​ 65,239 8.00 ​ International Bank of Commerce, Zapata ​ 72,402 36.46 ​ 16,881 8.500 ​ 15,888 8.00 ​ Commerce Bank ​ 91,239 34.83 ​ 22,265 8.500 ​ 20,956 8.00 % Tier 1 Capital (to Average Assets): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 1,953,711 16.65 % $ 469,267 4.00 % $ N/A N/A ​ International Bank of Commerce, Laredo ​ 1,268,078 15.21 ​ 333,576 4.00 ​ 416,970 5.00 ​ International Bank of Commerce, Oklahoma ​ ​ 201,202 ​ 14.79 ​ ​ 54,406 ​ 4.00 ​ ​ 68,007 ​ 5.00 ​ International Bank of Commerce, Brownsville ​ 185,112 17.41 ​ 42,529 4.00 ​ 53,161 5.00 ​ International Bank of Commerce, Zapata ​ 72,402 19.08 ​ 15,179 4.00 ​ 18,974 5.00 ​ Commerce Bank ​ 91,239 18.18 ​ 20,073 4.00 ​ 25,091 5.00 ​ ​

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2020
Fair Value	(21) Fair Value ASC Topic 820, “Fair Value Measurements and Disclosures” (“ASC 820”) defines fair value, establishes a framework for measuring fair value in generally accepted accounting principles, and expands disclosures about fair value measurements. ASC 820 applies to all financial instruments that are being measured and reported on a fair value basis. ASC 820 defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date; it also establishes a fair value hierarchy that prioritizes the inputs used in valuation methodologies into the following three levels: ● Level 1 Inputs—Unadjusted quoted prices in active markets for identical assets or liabilities. ● Level 2 Inputs—Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. ● Level 3 Inputs—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, discounted cash flow methodologies, or other valuation techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. A description of the valuation methodologies used for instruments measured at fair value, as well as the general classification of such instruments pursuant to the valuation hierarchy is set forth below. The following table represents financial instruments reported on the consolidated statements of condition at their fair value as of December 31, 2020 by level within the fair value measurement hierarchy. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at ​ ​ ​ ​ ​ ​ Reporting Date Using ​ ​ ​ ​ ​ ​ (in Thousands) ​ ​ ​ ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Prices in ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Active ​ Significant ​ ​ ​ ​ ​ ​ Assets/Liabilities ​ Markets for ​ Other ​ Significant ​ ​ ​ Measured at ​ Identical ​ Observable ​ Unobservable ​ ​ ​ Fair Value ​ Assets ​ Inputs ​ Inputs ​ ​ ​ December 31, 2020 ​ (Level 1) ​ (Level 2) ​ (Level 3) ​ Measured on a recurring basis: ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Available for sale debt securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential mortgage-backed securities ​ $ 3,029,954 ​ $ — ​ $ 3,029,954 ​ $ — ​ States and political subdivisions ​ 50,814 ​ — ​ 50,814 ​ — ​ Equity Securities ​ 6,202 ​ 6,202 ​ — ​ — ​ ​ ​ $ 3,086,970 ​ $ 6,202 ​ $ 3,080,768 ​ $ — ​ ​ The following table represents financial instruments reported on the consolidated balance sheets at their fair value as of December 31, 2019 by level within the fair value measurement hierarchy. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at ​ ​ ​ ​ ​ ​ Reporting Date Using ​ ​ ​ ​ ​ ​ (in Thousands) ​ ​ ​ ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Prices in ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Active ​ Significant ​ ​ ​ ​ ​ ​ Assets/Liabilities ​ Markets for ​ Other ​ Significant ​ ​ ​ Measured at ​ Identical ​ Observable ​ Unobservable ​ ​ ​ Fair Value ​ Assets ​ Inputs ​ Inputs ​ ​ ​ December 31, 2019 ​ (Level 1) ​ (Level 2) ​ (Level 3) ​ Measured on a recurring basis: ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Available for sale securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential mortgage - backed securities ​ $ 3,285,548 ​ $ — ​ $ 3,285,548 ​ $ — ​ States and political subdivisions ​ 93,375 ​ — ​ 93,375 ​ — ​ Equity Securities ​ 6,095 ​ 6,095 ​ — ​ — ​ ​ ​ $ 3,385,018 ​ $ 6,095 ​ $ 3,378,923 ​ $ — ​ ​ For the years ended December 31, 2020 and December 31, 2019, debt investment securities available-for-sale are classified within Level 2 of the valuation hierarchy. Equity securities with readily determinable fair values are classified within Level 1. For debt securities classified as Level 2 in the fair value hierarchy, we obtain fair value measurements from an independent pricing service. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other things. Certain financial instruments are measured at fair value on a nonrecurring basis. They are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (for example, when there is evidence of impairment). The following table represents financial instruments measured at fair value on a non-recurring basis as of and for the period ended December 31, 2020 by level within the fair value measurement hierarchy: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at Reporting ​ ​ ​ ​ ​ ​ ​ ​ Date Using ​ ​ ​ ​ ​ ​ ​ ​ (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets/Liabilities ​ Prices in ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Measured at ​ Active ​ Significant ​ ​ ​ ​ ​ ​ ​ ​ Fair Value ​ Markets for ​ Other ​ Significant ​ Net Provision ​ ​ Period ended ​ Identical ​ Observable ​ Unobservable ​ (Credit) ​ ​ December 31, ​ Assets ​ Inputs ​ Inputs ​ During ​ ​ 2020 ​ (Level 1) ​ (Level 2) ​ (Level 3) ​ Period Measured on a non-recurring basis: ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Watch-List doubtful loans ​ $ 393 ​ $ — ​ $ — ​ $ 393 ​ $ (86) Other real estate owned ​ 6,241 ​ — ​ — ​ 6,241 ​ 1,539 ​ The following table represents financial instruments measured at fair value on a non-recurring basis as of and for the year ended December 31, 2019 by level within the fair value measurement hierarchy: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at Reporting ​ ​ ​ ​ ​ ​ ​ ​ Date Using ​ ​ ​ ​ ​ ​ ​ ​ (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets/Liabilities ​ Prices in ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Measured at ​ Active ​ Significant ​ ​ ​ ​ ​ ​ ​ ​ Fair Value ​ Markets ​ Other ​ Significant ​ Net (Credit) ​ ​ Year ended ​ for Identical ​ Observable ​ Unobservable ​ Provision ​ ​ December 31, ​ Assets ​ Inputs ​ Inputs ​ During ​ ​ 2019 ​ (Level 1) ​ (Level 2) ​ (Level 3) ​ Period Measured on a non-recurring basis: ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Impaired loans ​ $ 826 ​ $ — ​ $ — ​ $ 826 ​ $ 43 Other real estate owned ​ 21,614 ​ — ​ — ​ 21,614 ​ 322 Equity investment without a readily determinable fair value ​ ​ 28,166 ​ ​ — ​ ​ — ​ ​ 28,166 ​ ​ 4,775 ​ Our assets measured at fair value on a non-recurring basis are limited to loans classified as Watch List – Doubtful and other real estate owned. At December 31, 2019, assets measured at fair value on a non-recurring basis also included an equity investment without a readily determinable fair value. The fair value of Watch-List Doubtful loans is derived in accordance with FASB ASC 310, “Receivables”. They are primarily comprised of collateral-dependent commercial loans. As the primary sources of loan repayments decline, the secondary repayment source, the collateral, takes on greater significance. Correctly evaluating the fair value becomes even more important. Re-measurement of the loan to fair value is done through a specific valuation allowance included in the ACL. The fair value of the loan is based on the fair value of the collateral, as determined through either an appraisal or evaluation process. The basis for our appraisal and appraisal review process is based on regulatory guidelines and strives to comply with all regulatory appraisal laws, regulations, and the Uniform Standards of Professional Appraisal Practice. All appraisals and evaluations are “as is” (the property’s highest and best use) valuations based on the current conditions of the property/project at that point in time. The determination of the fair value of the collateral is based on the net realizable value, which is the appraised value less any closing costs, when applicable. As of December 31, 2020, we had approximately $18,361,000 of doubtful commercial collateral dependent loans, of which approximately $16,587,000 had an appraisal performed within the immediately preceding twelve months and of which approximately $1,283,000 had an evaluation performed within the immediately preceding twelve months. As of December 31, 2019, we had approximately $2,955,000 of doubtful commercial collateral dependent loans, of which approximately $1,426,000 had an appraisal performed within the immediately preceding twelve months and of which approximately $847,000 had an evaluation performed within the immediately preceding twelve months. The determination to either seek an appraisal or to perform an evaluation begins in weekly credit quality meetings, where the committee analyzes the existing collateral values of the doubtful loans and where obsolete appraisals are identified. In order to determine whether we would obtain a new appraisal or perform an internal evaluation to determine the fair value of the collateral, the credit committee reviews the existing appraisal to determine if the collateral value is reasonable in view of the current use of the collateral and the economic environment related to the collateral. If the analysis of the existing appraisal does not find that the collateral value is reasonable under the current circumstances, we would obtain a new appraisal on the collateral or perform an internal evaluation of the collateral. The ultimate decision to get a new appraisal rests with the independent credit administration group. A new appraisal is not required if an internal evaluation, as performed by in-house experts, is able to appropriately update the original appraisal assumptions to reflect current market conditions and provide an estimate of the collateral’s market value for impairment analysis. The internal evaluations must be in writing and contain sufficient information detailing the analysis, assumptions and conclusions and they must support performing an evaluation in lieu of ordering a new appraisal. Other real estate owned is comprised of real estate acquired by foreclosure and deeds in lieu of foreclosure. Other real estate owned is carried at the lower of the recorded investment in the property or its fair value less estimated costs to sell such property (as determined by independent appraisal) within Level 3 of the fair value hierarchy. Prior to foreclosure, the value of the underlying loan is written down to the fair value of the real estate to be acquired by a charge to the ACL (formerly allowance for probable loan losses), if necessary. The fair value is reviewed periodically and subsequent write downs are made accordingly through a charge to operations. Other real estate owned is included in other assets on the consolidated financial statements. For the twelve months ended December 31, 2020, 2019 and 2018, we recorded approximately $22,000, $9,611,000 and $170,000, respectively, in charges to the ACL in connection with loans transferred to other real estate owned. For the twelve months ended December 31, 2020, 2019 and 2018, we recorded approximately $1,539,000, $322,000 and $3,071,000, respectively, in adjustments to fair value in connection with other real estate owned. The fair value estimates, methods, and assumptions for our financial instruments at December 31, 2020 and December 31, 2019 are outlined below. Cash and Cash Equivalents For these short-term instruments, the carrying amount is a reasonable estimate of fair value. Investment securities held-to-maturity The carrying amounts of investments held-to-maturity approximate fair value. Investment Securities For debt investment securities, which include U.S. Treasury securities, obligations of other U.S. government agencies, obligations of states and political subdivisions and mortgage pass through and related securities, fair values are from an independent pricing service. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other things. See disclosures of fair value of investment securities in Note 2. Loans Fair values are estimated for portfolios of loans with similar financial characteristics. Loans are segregated by type such as commercial, real estate and consumer loans as outlined by regulatory reporting guidelines. Each category is segmented into fixed and variable interest rate terms and by performing and non-performing categories. For variable rate performing loans, the carrying amount approximates the fair value. For fixed rate performing loans, except residential mortgage loans, the fair value is calculated by discounting scheduled cash flows through the estimated maturity using estimated market discount rates that reflect the credit and interest rate risk inherent in the loan. For performing residential mortgage loans, fair value is estimated by discounting contractual cash flows adjusted for prepayment estimates using discount rates based on secondary market sources or the primary origination market. Fixed rate performing loans are within Level 3 of the fair value hierarchy. At December 31, 2020 and December 31, 2019, the carrying amount of fixed rate performing loans was $1,812,413,000 and $1,503,811,000, respectively, and the estimated fair value was $1,747,257,000 and $1,481,239,000, respectively. Accrued Interest The carrying amounts of accrued interest approximate fair value. Deposits The fair value of deposits with no stated maturity, such as non-interest bearing demand deposit accounts, savings accounts and interest-bearing demand deposit accounts, was equal to the amount payable on demand as of December 31, 2020 and December 31, 2019. The fair value of time deposits is based on the discounted value of contractual cash flows. The discount rate is based on currently offered rates. Time deposits are within Level 3 of the fair value hierarchy. At December 31, 2020 and December 31, 2019, the carrying amount of time deposits was $2,153,541,000 and $2,012,300,000, respectively, and the estimated fair value was $2,148,976,000 and $2,011,950,000, respectively. Securities Sold Under Repurchase Agreements Securities sold under repurchase agreements are short-term maturities. Due to the contractual terms of the instruments, the carrying amounts approximated fair value at December 31, 2020 and December 31, 2019. Junior Subordinated Deferrable Interest Debentures We currently have floating rate junior subordinated deferrable interest debentures outstanding. Due to the contractual terms of the floating rate junior subordinated deferrable interest debentures, the carrying amounts approximated fair value at December 31, 2020 and December 31, 2019. Other Borrowed Funds We currently have long-term borrowings issued from the Federal Home Loan Bank (“FHLB”). At December 31, 2019, we also held some also short-term borrowings. Due to the contractual terms of the short-term borrowings, the carrying amounts approximated fair value at December 31, 2019. The long-term borrowings outstanding at December 31, 2020 and December 31, 2019 are fixed-rate borrowings and the fair value is based on established market spreads for similar types of borrowings. The fixed-rate long-term borrowings are included in Level 2 of the fair value hierarchy. At December 31, 2020, and December 31, 2019 the carrying amount of the fixed-rate long-term FHLB borrowings was $436,372,000 and $436,511,000, respectively and the estimated fair value was $480,475,000 and $465,017,000 respectively. Commitments to Extend Credit and Letters of Credit Commitments to extend credit and fund letters of credit are principally at current interest rates and therefore the carrying amount approximates fair value. Limitations Fair value estimates are made at a point in time, based on relevant market information and information about the financial instrument. These estimates do not reflect any premium or discount that could result from offering for sale at one time of our entire holdings of a particular financial instrument. Because no market exists for a significant portion of our financial instruments, fair value estimates are based on judgments regarding future expected loss experience, current economic conditions, risk characteristics of various financial 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 assumptions could significantly affect the estimates. Fair value estimates are based on existing on-and off-statement of condition financial instruments without attempting to estimate the value of anticipated future business and the value of assets and liabilities that are not considered financial instruments. Other significant assets and liabilities that are not considered financial assets or liabilities include the bank premises and equipment and core deposit value. In addition, the tax ramifications related to the effect of fair value estimates have not been considered in the above estimates.

International Bancshares Corpor

International Bancshares Corporation (Parent Company Only) Financial Information Statements of Condition	12 Months Ended
	Dec. 31, 2020
International Bancshares Corporation (Parent Company Only) Financial Information Statements of Condition	(22) International Bancshares Corporation (Parent Company Only) Financial Information Statements of Condition (Parent Company Only) December 31, 2020 and 2019 (Dollars in Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ASSETS ​ ​ ​ ​ ​ ​ ​ Cash ​ $ 66,252 ​ $ 24,290 ​ Other investments ​ 77,661 ​ 106,284 ​ Net loans ​ 11,950 ​ 12,100 ​ Investment in subsidiaries ​ 2,167,516 ​ 2,120,391 ​ Goodwill ​ ​ 3,365 ​ ​ 3,365 ​ Other assets ​ — ​ 264 ​ Total assets ​ $ 2,326,744 ​ $ 2,266,694 ​ LIABILITIES AND SHAREHOLDERS’ EQUITY ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ Junior subordinated deferrable interest debentures ​ $ 134,642 ​ $ 134,642 ​ Due to IBC Trading ​ 21 ​ 21 ​ Other liabilities ​ 14,083 ​ 13,978 ​ Total liabilities ​ 148,746 ​ 148,641 ​ Shareholders’ equity: ​ ​ ​ ​ ​ ​ ​ Common shares ​ 96,241 ​ 96,215 ​ Surplus ​ 149,334 ​ 148,075 ​ Retained earnings ​ 2,289,626 ​ 2,200,568 ​ Accumulated other comprehensive income (loss) ​ 20,825 ​ 2,345 ​ ​ ​ 2,556,026 ​ 2,447,203 ​ Less cost of shares in treasury ​ (378,028) ​ (329,150) ​ Total shareholders’ equity ​ 2,177,998 ​ 2,118,053 ​ Total liabilities and shareholders’ equity ​ $ 2,326,744 ​ $ 2,266,694 ​ ​

International Bancshares Corp_2

International Bancshares Corporation (Parent Company Only) Financial Information Statements of Income	12 Months Ended
	Dec. 31, 2020
International Bancshares Corporation (Parent Company Only) Financial Information Statements of Income	(23) International Bancshares Corporation (Parent Company Only) Financial Information Statements of Income (Parent Company Only) Years ended December 31, 2020, 2019 and 2018 (Dollars in Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 Income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Dividends from subsidiaries ​ $ 130,950 ​ $ 127,750 ​ $ 105,000 ​ Interest income on notes receivable ​ 357 ​ 922 ​ — ​ Interest income on other investments ​ (1,126) ​ (514) ​ 8,208 ​ Other ​ 5 ​ 18 ​ 1,988 ​ Total income ​ 130,186 ​ 128,176 ​ 115,196 ​ Expenses: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest expense (Debentures) ​ 3,832 ​ 6,435 ​ 6,989 ​ Provision for credit loss ​ ​ 27 ​ ​ — ​ ​ — ​ Other ​ 1,988 ​ 2,749 ​ 2,930 ​ Total expenses ​ 5,847 ​ 9,184 ​ 9,919 ​ Income before federal income taxes and equity in undistributed net income of subsidiaries ​ 124,339 ​ 118,992 ​ 105,277 ​ Income tax expense ​ (1,339) ​ (1,878) ​ 481 ​ Income before equity in undistributed net income of subsidiaries ​ 125,678 ​ 120,870 ​ 104,796 ​ Equity in undistributed net income of subsidiaries ​ 41,641 ​ 84,234 ​ 111,135 ​ Net income ​ $ 167,319 ​ $ 205,104 ​ $ 215,931 ​ ​

International Bancshares Corp_3

International Bancshares Corporation (Parent Company Only) Financial Information Statements of Cash Flows	12 Months Ended
	Dec. 31, 2020
International Bancshares Corporation (Parent Company Only) Financial Information Statements of Cash Flows	(24) International Bancshares Corporation (Parent Company Only) Financial Information Statements of Cash Flows (Parent Company Only) Years ended December 31, 2020, 2019 and 2018 (Dollars in Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 Operating activities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 167,319 ​ $ 205,104 ​ $ 215,931 ​ Adjustments to reconcile net income to net cash provided by operating activities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Provision for credit loss ​ ​ 27 ​ ​ — ​ ​ — ​ Unrealized loss (gain) on equity securities with readily determinable fair values ​ ​ 22 ​ ​ (16) ​ ​ 330 ​ Stock compensation expense ​ 743 ​ 980 ​ 1,035 ​ Increase (decrease) in other liabilities ​ 2,467 ​ (58) ​ (1,479) ​ Equity in undistributed net income of subsidiaries ​ (41,641) ​ (84,234) ​ (111,135) ​ Net cash provided by operating activities ​ 128,937 ​ 121,776 ​ 104,682 ​ Investing activities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net increase in notes receivable ​ — ​ (12,100) ​ — ​ (Decrease) increase in other assets and other investments ​ 31,289 ​ 5,915 ​ (7,891) ​ Net cash provided by (used in) investing activities ​ 31,289 ​ (6,185) ​ (7,891) ​ Financing activities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Redemption of long-term debt ​ — ​ (25,774) ​ — ​ Proceeds from stock transactions ​ 542 ​ 1,923 ​ 1,522 ​ Payments of cash dividends - common ​ (69,928) ​ (68,670) ​ (49,599) ​ Repurchase of outstanding common stock warrant ​ — ​ — ​ (29,005) ​ Purchase of treasury stock ​ (48,878) ​ (17,845) ​ (19,042) ​ Net cash used in financing activities ​ (118,264) ​ (110,366) ​ (96,124) ​ Increase in cash ​ 41,962 ​ 5,225 ​ 667 ​ Cash at beginning of year ​ 24,290 ​ 19,065 ​ 18,398 ​ Cash at end of year ​ $ 66,252 ​ $ 24,290 ​ $ 19,065 ​ ​

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Consolidation and Basis of Presentation	Consolidation and Basis of Presentation Our consolidated financial statements include the accounts of the International Bancshares Corporation, its wholly-owned Subsidiary Banks and its wholly-owned non-bank subsidiaries, IBC Trading Company, Premier Tierra Holdings, Inc., IBC Charitable and Community Development Corporation, and IBC Capital Corporation. All significant inter-company balances and transactions have been eliminated in consolidation. We, through our Subsidiary Banks, are primarily engaged in the business of banking, including the acceptance of checking and savings deposits and the making of commercial, real estate, personal, home improvement, automobile and other installment and term loans. Our primary markets are north, south, central, and southeast Texas and the state of Oklahoma. Each of our Subsidiary Banks is very active in facilitating international trade along the United States border with Mexico and elsewhere. Although our loan portfolio is diversified, the ability of our debtors to honor their contracts is primarily dependent upon the economic conditions in our trade area. In addition, the investment portfolio is directly impacted by fluctuations in market interest rates. We are subject to the regulations of certain federal agencies as well as the Texas Department of Banking and the Oklahoma Department of Banking and undergo periodic examinations by those regulatory authorities. Such agencies may require certain standards or impose certain limitations based on their judgments or changes in law and regulations. We own one insurance-related subsidiary, IBC Insurance Agency, Inc., a wholly owned subsidiary of our Subsidiary Bank, International Bank of Commerce, Laredo. The insurance-related subsidiary does not conduct underwriting activities. The preparation of the consolidated financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the dates of the statement of condition and income and expenses for the periods. Actual results could differ significantly from those estimates. Material estimates that are particularly susceptible to significant changes in the near-term relate to the determination of ACL.
Subsequent Events	Subsequent Events We have evaluated all events or transactions that occurred through the date we issued these financial statements. During this period, we did not have any material recognizable or non-recognizable subsequent events.
Investment Securities	Investment Securities We classify debt securities into one of these categories: held-to-maturity, available-for-sale, or trading. Such classifications are reassessed for appropriate classification at each reporting date. Securities that are intended and expected to be held until maturity are classified as “held-to-maturity” and are carried at amortized cost for financial statement reporting. Securities that are not positively expected to be held until maturity, but are intended to be held for an indefinite period of time are classified as “available-for-sale” or “trading” and are carried at their fair value. Unrealized holding gains and losses are included in net income for those securities classified as “trading”, while unrealized holding gains and losses related to those securities classified as “available-for-sale” are excluded from net income and reported net of tax as other comprehensive income and in shareholders’ equity as accumulated other comprehensive income (loss) until realized. In accordance with ASU 2016-13, which we adopted on January 1, 2020, available-for-sale and held-to-maturity debt securities in an unrealized loss position must be evaluated for the underlying cause of the loss. In the event that the deterioration in value is attributable to credit related reasons, then the amount of credit-related impairment would be recorded as a charge to our ACL with subsequent changes in the amount of impairment, up or down, also recorded through our ACL. The exception to this process will occur if we intend to sell an impaired available-for-sale debt security or if we will more likely than not be required to sell a credit impaired available-for-sale debt security prior to the value recovering to the security’s amortized cost. In those situations, the entire credit-related impairment amount would be required to be recognized in earnings. We have evaluated the debt securities classified as available-for-sale and held-to-maturity at December 31, 2020 and have determined that no debt securities in an unrealized loss position are arising from credit related reasons and have therefore not recorded any allowances for debt securities in our ACL for the period. Unrealized gains and losses related to equity securities with readily determinable fair values are included in net income. We did not maintain any trading securities during the three-year period ended December 31, 2020. Mortgage-backed securities held at December 31, 2020 and 2019 represent participating interests in pools of long-term first mortgage loans originated and serviced by the issuers of the securities. Mortgage-backed securities are either issued or guaranteed by the U.S. government or its agencies including Freddie Mac, Fannie Mae, Ginnie Mae or other non-government entities. Investments in residential mortgage-backed securities issued by Ginnie Mae are fully guaranteed by the U. S. government. Investments in residential mortgage-backed securities issued by Freddie Mac and Fannie Mae are not fully guaranteed by the U.S. government; however, we believe that the quality of the bonds is similar to other AAA rated bonds with limited credit risk, particularly given the placement of Fannie Mae and Freddie Mac into conservatorship by the federal government in 2008 and because securities issued by others that are collateralized by residential mortgage-backed securities issued by Fannie Mae or Freddie Mac are rated consistently as AAA rated securities. Market interest rate fluctuations can affect the prepayment speed of principal and the yield on the security. Premiums and discounts are amortized using the level yield or “interest method” over the terms of the securities. Declines in the fair value of held-to-maturity and available-for sale-securities below their cost that are deemed to be other than temporary are reflected in earnings as realized losses. In determining whether other-than-temporary impairment exists, management considers many factors, including (i) the length of time and the extent to which the fair value has been less than cost, (ii) the financial condition and near-term prospects of the issuer, and (iii) our intent to hold and our determination of whether we will more likely than not be required to sell the security prior to a recovery in fair value. If we determine that (i) we intend to sell the security or (ii) it is more likely than not that we will be required to sell the security before it’s anticipated recovery, the other-than-temporary impairment that is recognized in earnings is equal to the difference between the fair value of the security and our amortized cost of the security. If we determine that we (i) do not intend to sell the security and (ii) we will not be more likely than not required to sell the security before it’s anticipated recovery, the other-than-temporary impairment is segregated into its two components (i) the amount of impairment related to credit loss and (ii) the amount of impairment related to other factors. The difference between the present value of the cash flows expected to be collected and the amortized cost is the credit loss recognized through earnings and an adjustment to the cost basis of the security. The amount of impairment related to other factors is included in other comprehensive income (loss). Gains and losses on the sale of securities are recorded on the trade date and are determined using the specific identification method.
Equity Securities	Equity Securities
Provision and Allowance for Probable Loan Losses	Provision and Allowance for Credit Losses We adopted the provisions of Accounting Standards Update No. 2016-13 to ASC 326, “Financial Instruments – Credit Losses,” on January 1, 2020. ASU 2016-13 replaces the long-standing incurred loss model with an expected credit loss model that recognizes credit losses over the life of a financial asset. Expected credit losses capture historical information, current conditions, and reasonable and supportable forecasts of future conditions. The ACL is deducted from the amortized cost of an instrument to present the net amount expected to be collected on the financial asset. Our ACL primarily consists of the aggregate ACL estimates of our Subsidiary Banks. The estimates are established through charges to operations in the form of charges to provisions for credit loss expense. Loan losses or recoveries are charged or credited directly to the ACL. The ACL of each Subsidiary Bank is maintained at a level considered appropriate by management, based on estimated current expected credit losses in the current loan portfolio, including information about past events, current conditions and reasonable and supportable forecasts. Our management continually reviews the ACL of the Subsidiary Banks using the amounts determined from the estimates established on specific doubtful loans, the estimate established on quantitative historical loss percentages, and the estimate based on qualitative current conditions and reasonable and supportable two-year forecasted data. Our methodology reverts to the average lifetime loss-rate beyond the forecast period when we can no longer develop reasonable and supportable forecasts. Should any of the factors considered by management in evaluating the adequacy of the estimate for current expected credit losses change, our estimate of current expected credit losses could also change, which could affect the level of future credit loss expense. While the calculation of our ACL utilizes management’s best judgment and all information reasonably available, the adequacy of the ACL is dependent on a variety of factors beyond our control, including, among other things, the performance of the entire loan portfolio, the economy, government actions, changes in interest rates and the view of regulatory authorities towards loan classifications. We believe that the allowance for probable loan losses is adequate. The Subsidiary Banks charge-off that portion of any loan which management considers to represent a loss as well as that portion of any other loan which is classified as a “loss” by bank examiners. Commercial, financial and agricultural or real estate loans are generally considered by management to represent a loss, in whole or part, (i) when an exposure beyond any collateral coverage is apparent, (ii) when no further collection of the portion of the loan so exposed is anticipated based on actual results, (iii) when the credit enhancements, if any, are not adequate, and (iv) when the borrower’s financial condition would indicate so. Generally, unsecured consumer loans are charged-off when 90 days past due.
Loans	Loans Loans are reported at the principal balance outstanding, net of unearned discounts. Interest income on loans is reported on an accrual basis. Loan fees and costs associated with originating the loans are accreted or amortized over the life of the loan using the interest method. We originate mortgage loans that may subsequently be sold to an unaffiliated third party. The loans are not securitized and if sold, are sold without recourse. Loans held for sale are carried at cost and the principal amount outstanding is not significant to the consolidated financial statements.
Doubtful Loans	Doubtful Loans Doubtful loans are those loans where it is probable that all amounts due according to contractual terms of the loan agreement will not be collected. Doubtful loans are measured based on (1) the present value of expected future cash flows discounted at the loan’s effective interest rate; (2) the loan’s observable market price; or (3) the fair value of the collateral if the loan is collateral dependent. Substantially all our doubtful loans are measured at the fair value of the collateral. In limited cases, we may use other methods to determine the level of impairment of a loan if such loan is not collateral dependent.
Troubled Debt Restructured Loans	Troubled Debt Restructured Loans
Non-Accrual Loans	Non-Accrual Loans The non-accrual loan policy of our Subsidiary Banks is to discontinue the accrual of interest on loans when management determines that it is probable that future interest accruals will be un-collectible. As it relates to consumer loans, management charges-off those loans when the loan is contractually 90 days past due. Under special circumstances, a consumer or non-consumer loan may be more than 90 days delinquent as to interest or principal and not be placed on non-accrual status. This situation generally results when a Subsidiary Bank has a borrower who is experiencing financial difficulties, but not to the extent that requires a restructuring of indebtedness. The majority of this category is composed of loans that are considered to be adequately secured and/or for which there are expected future payments. When a loan is placed on non-accrual status, any interest accrued, not paid is reversed and charged to operations against interest income. As it relates to non-consumer loans that are not 90 days past due, management will evaluate each of these loans to determine if placing the loan on non-accrual status is warranted. Interest income on non-accrual loans is recognized only to the extent payments are received or when, in management’s opinion, the debtor’s financial condition warrants reestablishment of interest accruals.
Other Real Estate Owned and Repossessed Assets	Other Real Estate Owned and Repossessed Assets Other real estate owned is comprised of real estate acquired by foreclosure and deeds in lieu of foreclosure. Other real estate is carried at the lower of the recorded investment in the property or its fair value less estimated costs to sell such property (as determined by independent appraisal). Prior to foreclosure, the value of the underlying loan is written down to the fair value of the real estate to be acquired by a charge to the ACL, if necessary. Any subsequent write-downs are charged against other non-interest expense through a valuation allowance. Other real estate owned totaled approximately $60,487,300 and $71,103,000 at December 31, 2020 and 2019, respectively. Other real estate owned is included in other assets. Repossessed assets consist primarily of non-real estate assets acquired by foreclosure. Prior to foreclosure, the value of the underlying loan is written down to the fair value of the asset to be repossessed by a charge to the ACL, if necessary. Repossessed assets are included in other assets on the consolidated financial statements and totaled approximately $5,779,000 and $7,137,000 at December 31, 2020 and 2019, respectively.
Bank Premises and Equipment	Bank Premises and Equipment Bank premises and equipment are stated at cost less accumulated depreciation. Depreciation is computed on straight-line and accelerated methods over the estimated useful lives of the assets. Repairs and maintenance are charged to operations as incurred and expenditures for renewals and betterments are capitalized. We primarily own all the property we occupy, with the exception of certain branches operating in grocery store or retail shopping centers and certain ATM locations, which are all under operating leases as classified under guidance prior to the issuance of ASU 2016-02, “Leases.” We adopted the guidance in ASU 2016-02 on January 1, 2019 and recorded a right of use asset and a lease liability other assets other liabilities
Other Investments	Other Investments Other investments include equity investments in non-financial companies, as well as equity securities with no readily determinable fair market value. Equity investments are accounted for using the equity method of accounting. Equity securities with no readily determinable fair value are accounted for using the cost method.
Revenue recognition	Revenue Recognition
Income Taxes	Income Taxes Deferred income tax assets and liabilities are determined using the asset and liability method. Under this method, the net deferred tax asset or liability is determined based on the tax effects of the differences between the book and tax basis of the various balance sheet assets and liabilities and gives current recognition to changes in tax rates and laws. We file a consolidated federal income tax return with our subsidiaries. Recognition of deferred tax assets is based on management’s assessment that the benefit related to certain temporary differences, tax operating loss carry forwards, and tax credits are more likely than not to be realized. A valuation allowance is recorded for the amount of the deferred tax items for which it is more likely than not that the tax benefits will not be realized. We evaluate uncertain tax positions at the end of each reporting period. We may recognize the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The tax benefit recognized in the financial statements from any such a position is measured based on the largest benefit that has a greater than fifty percent likelihood of being realized upon ultimate settlement. As of December 31, 2020 and 2019, respectively, after evaluating all uncertain tax positions, we have recorded no liability for unrecognized tax benefits at the end of the reporting period. We would recognize any interest accrued on unrecognized tax benefits as other interest expense and penalties as other non-interest expense. During the years ended December 31, 2020, 2019 and 2018, we recognized no interest expense or penalties related to uncertain tax positions. We file consolidated tax returns in the U.S. Federal jurisdiction and various state jurisdictions. We are no longer subject to U.S. federal or state income tax examinations by tax authorities for years before 2017.
Stock Options	Stock Options Compensation expense for stock awards is based on the market price of the stock on the measurement date, which is generally the date of grant, and is recognized ratably over the service period of the award. The fair value of stock options granted was estimated using the Black-Sholes-Merton option-pricing model. This model was developed for use in estimating the fair value of publicly traded options that have no vesting restrictions and are fully transferable. Additionally, the model requires the input of highly subjective assumptions. Because our employee stock options have characteristics significantly different from those of publicly traded options, and because changes in the subjective input assumptions can materially affect the fair value estimate, in management’s opinion, the Black-Scholes-Merton option-pricing model does not necessarily provide a reliable single measure of the fair value of our stock options.
Net Income Per Share	Net Income Per Share Basic Earnings Per Share (“EPS”) is calculated by dividing net income by the weighted average number of common shares outstanding. The computation of diluted EPS assumes the issuance of common shares for all dilutive potential common shares outstanding during the reporting period. The dilutive effect of stock options is considered in earnings per share calculations, if dilutive, using the treasury stock method.
Goodwill and Identified Intangible Assets	Goodwill and Identified Intangible Assets Goodwill represents the excess of costs over fair value of assets of businesses acquired. Goodwill is tested for impairment at least annually or on an interim basis if an event triggering impairment may have occurred. As of October 1, 2020, after completing goodwill testing, we have determined that no goodwill impairment exists. Identified intangible assets are acquired assets that lack physical substance but can be distinguished from goodwill because of contractual or other legal rights or because the asset is capable of being sold or exchanged either on its own or in combination with a related contract, asset, or liability. Our identified intangible assets relate to core deposits and contract rights. As of December 31, 2020, we have determined that no impairment of identified intangibles exists. Identified intangible assets with definite useful lives are amortized on an accelerated basis over their estimated life. See Note 6—Goodwill and Other Intangible Assets.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Long-lived assets, such as property, plant and equipment, and purchased intangibles subject to amortization, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. Recoverability of assets to be held and used is measured by a comparison of the carrying value of the asset to the estimated undiscounted future cash flows expected to be generated by the asset. If the carrying value of an asset exceeds its estimated future cash flows, an impairment charge is recognized by the amount by which the carrying value of the asset exceeds the fair value of the asset. Assets to be disposed of would be separately presented in the statement of condition and reported at the lower of the carrying value or fair value less costs to sell, and are no longer depreciated. The assets and liabilities of a disposed group classified as held for sale would be presented separately in the appropriate asset and liability sections of the statement of condition.
Consolidated Statements of Cash Flows	Consolidated Statements of Cash Flows For purposes of the consolidated statements of cash flows, we consider all short-term investments with a maturity at date of purchase of three months or less to be cash equivalents. Also, we report transactions related to deposits and loans to customers on a net basis.
Accounting for Transfers and Servicing of Financial Assets	Accounting for Transfers and Servicing of Financial Assets We account for transfers and servicing of financial assets and extinguishments of liabilities based on the application of a financial-components approach that focuses on control. After a transfer of financial assets, we recognize the financial and servicing assets we control and liabilities we have incurred, derecognize financial assets when control has been surrendered and derecognize liabilities when extinguished. We have retained mortgage servicing rights in connection with the sale of mortgage loans. Because we may not initially identify loans as originated for resale, all loans are initially treated as held for investment. The value of the mortgage servicing rights are reviewed periodically for impairment and are amortized in proportion to, and over the period of estimated net servicing income or net servicing losses. The value of the mortgage servicing rights is not significant to the consolidated statements of condition.
Segments of an Enterprise and Related Information	Segments of an Enterprise and Related Information We operate as one segment. The operating information used by our chief executive officer for purposes of assessing performance and making operating decisions is the consolidated financial statements presented in this report. We have five active operating subsidiaries, namely, the Subsidiary Banks. We apply the provisions of ASC Topic 280, “Segment Reporting,” in determining our reportable segments and related disclosures.
Comprehensive Income (Loss)	Comprehensive Income (Loss) Comprehensive income (loss) consists of net income and other comprehensive income (loss). Other comprehensive income (loss) includes unrealized gains and losses on securities available for sale.
Advertising	Advertising Advertising costs are expensed as incurred.
Reclassifications	Reclassifications Certain amounts in the prior year’s presentations have been reclassified to conform to the current presentation. These reclassifications had no effect on previously reported net income or shareholders’ equity.
New Accounting Standards	New Accounting Standards In February 2016, the FASB issued Accounting Standards Update No. 2016-02 to ASC 820, “Leases.” The update amends existing standards for accounting for leases by lessees, with accounting for leases by lessors remaining mainly unchanged from current guidance. The update requires that lessees recognize a lease liability and a right of use asset for all leases (with the exception of short-term leases) at the commencement date of the lease and disclose key information about leasing arrangements. The update is to be applied on a modified retrospective basis for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the consolidated financial statements. The update is effective for interim and annual periods beginning after December 15, 2018. In January 2018, the FASB issued a proposal that provides an additional transition method that would allow entities to not apply the guidance in the update in the comparative periods presented in the consolidated financial statements, but instead recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. On January 1, 2019, we adopted the provisions of ASU 2016-02, “Leases.” As part of our business model, we primarily own all property we occupy, with the exception of certain branches operating in grocery stores or shopping centers and certain ATM locations that were classified as operating leases under previous guidance. The adoption of the standard did not have a significant impact on our consolidated financial statements. As of the date of adoption, we recorded a right of use asset and a lease liability other assets other liabilities In June 2016, the FASB issued Accounting Standards Update No. 2016-13 to ASC 326, “Financial Instruments – Credit Losses.” The update amends existing standards for accounting for credit losses for financial assets. The update requires that the expected credit losses on the financial instruments held as of the end of the period being reported be measured based on historical experience, current conditions, and reasonable and supportable forecasts. The update also expands the required disclosures related to significant estimates and judgements used in estimating credit losses, as well as the credit quality and underwriting standards of an organization’s financial assets. The update also amended the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit deterioration. The impact of the adoption of the standard is to be recorded as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is adopted. The accounting standard was effective for us on January 1, 2020. The task force formed last year, which includes key members of the teams that work with the calculation of the allowance for probable loan losses plus members representing the corporate accounting and risk management areas, has worked with the implementation of the update and validation to complete our model/tool. Based on the composition of the portfolio at December 31, 2019 and after finalizing the methodology, the adoption of the update increased our allowance for probable loan losses (referred to as the ACL under ASU 2016-13), by approximately 17.2%, resulting in a cumulative-effect adjustment to retained earnings of approximately $8.3 million, net of tax. Please refer to Note 4 – Allowance for Credit Losses and the Critical Accounting Policies discussion in Management’s Discussion and Analysis. In January 2017, the FASB issued Accounting Standards Update No. 2017-04 to ASC 350, “Intangibles – Goodwill and Other.” The update amends existing guidance in evaluating goodwill for impairment. The update requires that an entity perform its annual or interim goodwill test by comparing the fair value of a reporting unit with its carrying amount, with any impairment charges being recognized as the difference between the fair value and carrying value. The update is intended to standardize the impairment test for all business entities and also reduce the complexity and cost of evaluating goodwill for impairment. The update is effective for any annual or interim goodwill impairment tests in fiscal years beginning after December 15, 2019. The adoption of the update is not expected to have a significant impact to our consolidated financial statements. In March 2017, the FASB issued Accounting Standards Update No. 2017-08 to ASC 310, “Receivables – Nonrefundable Fees and Other Costs.” The update amends existing guidance on the amortization period for certain callable debt securities held at a premium. The update shortens the amortization period of the premium to the earliest call date. The update is effective for fiscal years beginning after December 15, 2018. The update is to be applied on a modified retrospective basis through a cumulative-effect adjustment to retained earnings as of the beginning of the period of adoption. The adoption of the update did not have a significant impact to our consolidated financial statements. In February 2018, the FASB issued Accounting Standards Update No. 2018-02 to ASC 220, “Income Statement – Reporting Comprehensive Income.” The update amends current guidance surrounding the reclassification of certain tax effects from accumulated other comprehensive income. The update is being issued as a result of the 2017 Tax Cuts and Jobs Act and the related impact to comprehensive income as a result of the application of current guidance with respect to changes in tax rates. Under current guidance, entities must re-evaluate the carrying value of deferred tax assets and liabilities and adjust them for the tax effect of the rate change and record that change through earnings. The result is that the tax effects for items that normally would only be recognized in comprehensive income will be recognized through earnings and results in stranded tax effects in accumulated other comprehensive income (loss) for the impact of the rate change. The update will allow a reclassification from accumulated other comprehensive income (loss) to retained earnings for the stranded tax effects resulting from the 2017 Tax Cuts and Jobs Act. The update is effective for all entities for fiscal years beginning after December 31, 2018. We adopted the provisions of ASU 2018-02 to ASC 220 in the second quarter of 2018. We recorded a one-time reclassification of $5,997,000 between accumulated comprehensive income (loss) and retained earnings as a result of the adoption of the accounting standards update. In August 2018, the FASB issued Accounting Standards Update No. 2018-13 to ASC 820, “Fair Value Measurement.” The update amends the existing guidance surrounding the disclosure of certain fair value measurements. The update removes certain disclosures that are no longer considered cost beneficial, modifies and, in some instances clarifies, the specific requirements of certain disclosures and adds disclosure requirements that are identified relevant. The update is effective for fiscal years beginning after December 15, 2019. The adoption of the update is not expected to have a significant impact on our consolidated financial statements. In January 20201, the FASB issued Accounting Standards Update No. 2021-01, “Reference Rate Reform (Topic 848): Scope.” The update clarifies the applicability of the practical expedients and exceptions issued in ASU 2020-04 to derivative instruments that use an interest rate for margining, discounting or contract price alignment that is modified as a result of reference rate reform. The update is intended to capture the incremental consequences of the scope clarification and tailor the existing guidance to derivative instruments affected by the discounting transition. The update was effective as of the date of issuance and can be applied through December 31, 2022. We have not adopted the provisions of the update and to not anticipate that the adoption of the update will have a significant impact on our consolidated financial statements.

Investment Securities (Tables)

Investment Securities (Tables)	12 Months Ended
	Dec. 31, 2020
Amortized cost and estimated fair value by type of investment security	The amortized cost and estimated fair value by type of investment security at December 31, 2020 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Held to Maturity ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ unrealized ​ unrealized ​ Estimated ​ Carrying ​ ​ ​ cost ​ gains ​ losses ​ fair value ​ value ​ ​ ​ (Dollars in Thousands) ​ Other securities $ 3,400 $ — $ — $ 3,400 $ 3,400 ​ Total investment securities ​ $ 3,400 ​ $ — ​ $ — ​ $ 3,400 ​ $ 3,400 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Available for Sale Debt Securities ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ unrealized ​ unrealized ​ Estimated ​ Carrying ​ ​ ​ cost ​ gains ​ losses ​ fair value ​ value (1) ​ ​ ​ (Dollars in Thousands) ​ Residential mortgage-backed securities $ 3,006,592 $ 32,701 $ (9,339) $ 3,029,954 $ 3,029,954 ​ Obligations of states and political subdivisions ​ 47,697 ​ 3,131 ​ (14) ​ 50,814 ​ 50,814 ​ Total investment securities ​ $ 3,054,289 ​ $ 35,832 ​ $ (9,353) ​ $ 3,080,768 ​ $ 3,080,768 ​ (1) Included in the carrying value of residential mortgage- backed securities are $371,407 of mortgage-backed securities issued by Ginnie Mae and $2,658,547 of mortgage-backed securities issued by Fannie Mae and Freddie Mac The amortized cost and estimated fair value by type of investment security at December 31, 2019 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Held to Maturity ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortized ​ unrealized ​ unrealized ​ Estimated ​ Carrying ​ ​ ​ cost ​ gains ​ losses ​ fair value ​ value ​ ​ ​ (Dollars in Thousands) ​ Other securities $ 2,400 $ — $ — $ 2,400 $ 2,400 ​ Total investment securities ​ $ 2,400 ​ $ — ​ $ — ​ $ 2,400 ​ $ 2,400 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Available for Sale ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ Estimated ​ ​ ​ ​ ​ ​ Amortized ​ unrealized ​ unrealized ​ fair ​ Carrying ​ ​ ​ cost ​ gains ​ losses ​ value ​ value (1) ​ ​ ​ (Dollars in Thousands) ​ Residential mortgage-backed securities $ 3,285,623 $ 16,534 $ (16,609) $ 3,285,548 $ 3,285,548 ​ Obligations of states and political subdivisions ​ 90,447 ​ 2,933 ​ (5) ​ 93,375 ​ 93,375 ​ Total investment securities ​ $ 3,376,070 ​ $ 19,467 ​ $ (16,614) ​ $ 3,378,923 ​ $ 3,378,923 ​ (1) Included in the carrying value of residential mortgage- backed securities are $571,247 of mortgage-backed securities issued by Ginnie Mae, $2,714,301 of mortgage-backed securities issued by Fannie Mae and Freddie Mac
Amortized cost and fair value of investment securities, by contractual maturity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Held to Maturity ​ Available for Sale ​ ​ ​ Amortized ​ Estimated ​ Amortized ​ Estimated ​ ​ ​ Cost ​ fair value ​ Cost ​ fair value ​ ​ ​ (Dollars in Thousands) ​ Due in one year or less $ 1,200 $ 1,200 $ — $ — ​ Due after one year through five years ​ 2,200 ​ 2,200 ​ — ​ — ​ Due after five years through ten years ​ — ​ — ​ 355 ​ 356 ​ Due after ten years ​ — ​ — ​ 47,342 ​ 50,458 ​ Residential mortgage-backed securities ​ — ​ — ​ 3,006,592 ​ 3,029,954 ​ Total investment securities ​ $ 3,400 ​ $ 3,400 ​ $ 3,054,289 ​ $ 3,080,768 ​
Gross unrealized losses on investment securities and the related fair value	Gross unrealized losses on investment securities and the fair value of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at December 31, 2020 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less than 12 months ​ 12 months or more ​ Total ​ ​ ​ ​ ​ ​ Unrealized ​ ​ ​ ​ Unrealized ​ ​ ​ ​ Unrealized ​ ​ ​ Fair Value ​ Losses ​ Fair Value ​ Losses ​ Fair Value ​ Losses ​ ​ ​ (Dollars in Thousands) ​ Available for sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential mortgage-backed securities $ 1,462,232 $ (9,339) $ — $ — $ 1,462,232 $ (9,339) ​ Obligations of states and political subdivisions ​ — ​ — ​ 757 ​ (14) ​ 757 ​ (14) ​ ​ ​ $ 1,462,232 ​ $ (9,339) ​ $ 757 ​ $ (14) ​ $ 1,462,989 ​ $ (9,353) ​ ​ Gross unrealized losses on investment securities and the fair value of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous loss position, at December 31, 2019 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less than 12 months ​ 12 months or more ​ Total ​ ​ ​ ​ ​ ​ Unrealized ​ ​ ​ ​ Unrealized ​ ​ ​ ​ Unrealized ​ ​ ​ Fair Value ​ Losses ​ Fair Value ​ Losses ​ Fair Value ​ Losses ​ ​ ​ (Dollars in Thousands) ​ Available for sale: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential mortgage-backed securities $ 523,031 $ (2,269) $ 1,448,109 $ (14,340) $ 1,971,140 $ (16,609) ​ Obligations of states and political subdivisions ​ 766 ​ (5) ​ — ​ — ​ 766 ​ (5) ​ ​ ​ $ 523,797 ​ $ (2,274) ​ $ 1,448,109 ​ $ (14,340) ​ $ 1,971,906 ​ $ (16,614) ​ ​
Summary of unrealized and realized gains and losses recognized in net income on equity securities	​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, 2020 ​ ​ (Dollars in Thousands) ​ ​ ​ Net gains recognized during the period on equity securities $ ​ 107 Less: Net gains and (losses) recognized during the period on equity securities sold during the period ​ ​ — ​ ​ ​ ​ ​ Unrealized gains recognized during the reporting period on equity securities still held at the reporting date ​ $ ​ 107 ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, 2019 ​ ​ (Dollars in Thousands) ​ ​ ​ Net gains recognized during the period on equity securities $ ​ 158 Less: Net gains and (losses) recognized during the period on equity securities sold during the period ​ ​ — ​ ​ ​ ​ ​ Unrealized losses recognized during the reporting period on equity securities still held at the reporting date ​ $ ​ 158 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, 2018 ​ ​ (Dollars in Thousands) ​ ​ ​ Net losses recognized during the period on equity securities $ ​ (388) Less: Net gains and (losses) recognized during the period on equity securities sold during the period ​ ​ — ​ ​ ​ ​ ​ Unrealized losses recognized during the reporting period on equity securities still held at the reporting date ​ $ ​ (388)

Loans (Tables)

Loans (Tables)	12 Months Ended
	Dec. 31, 2020
Summary of loans, by loan type	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ ​ ​ 2020 ​ 2019 ​ ​ ​ (Dollars in Thousands) ​ Commercial, financial and agricultural $ 4,516,288 $ 3,379,837 ​ Real estate - mortgage ​ 999,144 ​ 1,140,377 ​ Real estate - construction ​ 1,846,757 ​ 2,185,883 ​ Consumer ​ 40,595 ​ 47,800 ​ Foreign ​ 138,970 ​ 141,049 ​ Total loans ​ $ 7,541,754 ​ $ 6,894,946 ​

Allowance for Credit Losses (Ta

Allowance for Credit Losses (Tables)	12 Months Ended
	Dec. 31, 2020
Loans individually or collectively evaluated for their impairment and related allowance, by loan class	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ Domestic ​ ​ ​ ​ Foreign ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ real estate: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ other Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ construction & real estate: ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ land ​ farmland & ​ real estate: ​ Residential: ​ Residential: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ development ​ commercial ​ multifamily ​ first lien ​ junior lien ​ Consumer ​ Foreign ​ Total ​ ​ (Dollars in Thousands) ​ Balance at December 31, $ 11,145 ​ $ 18,152 ​ $ 16,533 ​ $ 1,786 ​ $ 3,762 ​ $ 7,535 ​ $ 542 ​ $ 823 ​ $ 60,278 ​ Adoption of ASU 2016-13 ​ ​ 4,247 ​ ​ 13,391 ​ ​ (4,292) ​ ​ (355) ​ ​ (1,580) ​ ​ (429) ​ ​ (225) ​ ​ (410) ​ ​ 10,347 ​ Losses charge to allowance ​ (8,936) ​ (19) ​ ​ (55) ​ — ​ (160) ​ (124) ​ (280) ​ — ​ (9,574) ​ Recoveries credited to allowance ​ 2,191 ​ 35 ​ 117 ​ — ​ 21 ​ 186 ​ 69 ​ 10 ​ 2,629 ​ Net losses charged to allowance ​ (6,745) ​ 16 ​ 62 ​ — ​ (139) ​ 62 ​ (211) ​ 10 ​ (6,945) ​ Provision (credit) charged to operations ​ 13,261 ​ ​ 6,053 ​ 17,697 ​ 3,620 ​ 1,831 ​ 2,402 ​ 185 ​ 330 ​ 45,379 ​ Balance at December 31, ​ $ 21,908 ​ $ 37,612 ​ $ 30,000 ​ $ 5,051 ​ $ 3,874 ​ $ 9,570 ​ $ 291 ​ $ 753 ​ $ 109,059 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ Domestic ​ ​ ​ ​ Foreign ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ real estate: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ other Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ construction & real estate: ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ land ​ farmland & ​ real estate: ​ Residential: ​ Residential: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial development ​ commercial ​ multifamily ​ first lien ​ junior lien ​ Consumer ​ Foreign ​ Total ​ ​ (Dollars in Thousands) ​ Balance at December 31, $ 12,596 ​ $ 15,123 ​ $ 19,353 ​ $ 1,808 ​ $ 3,467 ​ $ 7,719 ​ $ 447 ​ $ 871 $ 61,384 ​ Losses charge to allowance ​ (14,412) ​ (39) ​ (7,353) ​ — ​ (201) ​ (435) ​ (487) ​ (1) ​ (22,928) ​ Recoveries credited to allowance ​ 2,196 ​ 113 ​ 318 ​ — ​ 26 ​ 286 ​ 40 ​ — ​ 2,979 ​ Net losses charged to allowance ​ (12,216) ​ 74 ​ (7,035) ​ — ​ (175) ​ (149) ​ (447) ​ (1) ​ (19,949) ​ Provision (credit) charged to operations ​ 10,765 ​ 2,955 ​ 4,215 ​ (22) ​ 470 ​ (35) ​ 542 ​ (47) ​ 18,843 ​ Balance at December 31, ​ $ 11,145 ​ $ 18,152 ​ $ 16,533 ​ $ 1,786 ​ $ 3,762 ​ $ 7,535 ​ $ 542 ​ $ 823 ​ $ 60,278 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2018 ​ ​ Domestic ​ Foreign ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ real estate: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ other Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ construction & real estate: ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ land ​ farmland & ​ real estate: ​ Residential: ​ Residential: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial development ​ commercial ​ multifamily ​ first lien ​ junior lien ​ Consumer ​ Foreign ​ Total ​ (Dollars in Thousands) Balance at December 31, $ 27,905 $ 11,675 $ 16,663 $ 1,109 $ 2,950 $ 6,103 $ 440 $ 842 $ 67,687 ​ Losses charge to allowance ​ (14,220) ​ (1) ​ (70) ​ — ​ (122) ​ (347) ​ (362) ​ (3) ​ (15,125) ​ Recoveries credited to allowance ​ 1,981 ​ 25 ​ 246 ​ — ​ 36 ​ 369 ​ 43 ​ 10 ​ 2,710 ​ Net losses charged to allowance ​ (12,239) ​ 24 ​ 176 ​ — ​ (86) ​ 22 ​ (319) ​ 7 ​ (12,415) ​ Provision (credit) charged to operations ​ (3,070) ​ 3,424 ​ 2,514 ​ 699 ​ 603 ​ 1,594 ​ 326 ​ 22 ​ 6,112 ​ Balance at December 31, ​ $ 12,596 ​ $ 15,123 ​ $ 19,353 ​ $ 1,808 ​ $ 3,467 ​ $ 7,719 ​ $ 447 ​ $ 871 ​ $ 61,384 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ Loans Individually ​ Loans Collectively ​ ​ ​ Evaluated For ​ Evaluated For ​ ​ ​ Impairment ​ Impairment ​ ​ ​ Recorded ​ ​ ​ ​ Recorded ​ ​ ​ ​ ​ ​ Investment ​ Allowance ​ Investment ​ Allowance ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial $ 1,189 $ 209 $ 1,784,747 $ 21,699 ​ Commercial real estate: other construction & land development ​ 17,496 ​ 70 ​ 1,829,261 ​ 37,542 ​ Commercial real estate: farmland & commercial ​ 439 ​ — ​ 2,288,869 ​ 30,000 ​ Commercial real estate: multifamily ​ 134 ​ — ​ 440,910 ​ 5,051 ​ Residential: first lien ​ 151 ​ — ​ 404,968 ​ 3,874 ​ Residential: junior lien ​ 38 ​ — ​ 593,987 ​ 9,570 ​ Consumer ​ — ​ — ​ 40,595 ​ 291 ​ Foreign ​ — ​ — ​ 138,970 ​ 753 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 19,447 ​ $ 279 ​ $ 7,522,307 ​ $ 108,780 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ Loans Individually ​ Loans Collectively ​ ​ ​ Evaluated For ​ Evaluated For ​ ​ ​ Impairment ​ Impairment ​ ​ ​ Recorded ​ ​ ​ ​ Recorded ​ ​ ​ ​ ​ ​ Investment ​ Allowance ​ Investment ​ Allowance ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial $ 1,935 $ 249 $ 1,290,725 $ 10,895 ​ Commercial real estate: other construction & land development ​ 938 ​ 116 ​ 2,184,945 ​ 18,037 ​ Commercial real estate: farmland & commercial ​ 1,208 ​ — ​ 1,895,539 ​ 16,533 ​ Commercial real estate: multifamily ​ 165 ​ — ​ 190,265 ​ 1,786 ​ Residential: first lien ​ 6,278 ​ — ​ 427,623 ​ 3,762 ​ Residential: junior lien ​ 692 ​ — ​ 705,784 ​ 7,535 ​ Consumer ​ 1,195 ​ — ​ 46,605 ​ 542 ​ Foreign ​ 264 ​ — ​ 140,785 ​ 823 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 12,675 ​ $ 365 ​ $ 6,882,271 ​ $ 59,913 ​
Loans accounted on non-accrual basis, by loan class	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ December 31, 2019 ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ ​ ​ ​ Commercial $ 1,189 $ 1,901 ​ Commercial real estate: other construction & land development ​ 17,496 ​ 938 ​ Commercial real estate: farmland & commercial ​ 439 ​ 1,208 ​ Commercial real estate: multifamily ​ 134 ​ 165 ​ Residential: first lien ​ 526 ​ 670 ​ Residential: junior lien ​ 38 ​ — ​ Consumer ​ — ​ 4 ​ Total non-accrual loans ​ $ 19,822 ​ $ 4,886 ​
Impaired loans, by loan class	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ Unpaid ​ ​ ​ ​ Average ​ ​ ​ ​ ​ ​ Recorded ​ Principal ​ Related ​ Recorded ​ Interest ​ ​ ​ Investment ​ Balance ​ Allowance ​ Investment ​ Recognized ​ ​ ​ (Dollars in Thousands) Loans with Related Allowance ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ $ 510 ​ $ 516 ​ $ 249 ​ $ 514 ​ $ — ​ Commercial real estate: other construction & land development ​ ​ 126 ​ ​ 169 ​ ​ 116 ​ 131 ​ — ​ Total impaired loans with related allowance ​ $ 636 ​ $ 685 ​ $ 365 ​ $ 645 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ Unpaid ​ Average ​ ​ ​ ​ ​ Recorded ​ Principal ​ Recorded ​ Interest ​ ​ Investment ​ Balance ​ Investment ​ Recognized ​ ​ (Dollars in Thousands) Loans with No Related Allowance ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial $ 1,425 ​ $ 1,516 ​ $ 18,794 ​ $ 2 ​ Commercial real estate: other construction & land development ​ 812 ​ 1,133 ​ 1,737 ​ — ​ Commercial real estate: farmland & commercial ​ 1,208 ​ 1,841 ​ 22,357 ​ — ​ Commercial real estate: multifamily ​ 165 ​ 168 ​ 651 ​ — ​ Residential: first lien ​ 6,278 ​ 6,445 ​ 6,988 ​ 309 ​ Residential: junior lien ​ 692 ​ 692 ​ 1,023 ​ 42 ​ Consumer ​ 1,195 ​ 1,196 ​ 1,117 ​ — ​ Foreign ​ 264 ​ 264 ​ 278 ​ 12 ​ Total impaired loans with no related allowance ​ $ 12,039 ​ $ 13,255 ​ $ 52,945 ​ $ 365 ​
Loans accounted for as trouble debt restructuring, by Watch List Doubtful loans	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 December 31, 2019 ​ ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ ​ ​ ​ Commercial $ — $ 32 ​ Residential: first lien ​ ​ 4,078 ​ ​ 5,608 ​ Residential: junior lien ​ ​ 521 ​ ​ 692 ​ Consumer ​ ​ 989 ​ ​ 1,192 ​ Foreign ​ ​ 233 ​ ​ 264 ​ Total troubled debt restructuring ​ $ 5,821 ​ $ 7,788 ​
Information regarding the aging of past due loans, by loan class	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 90 Days or ​ Total ​ ​ ​ ​ ​ ​ ​ ​ ​ 30 - 59 ​ 60 - 89 ​ 90 Days or ​ greater & ​ Past ​ ​ ​ ​ Total ​ ​ ​ Days ​ Days ​ Greater ​ still accruing ​ Due ​ Current ​ Portfolio ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial $ 1,931 $ 1,109 $ 563 $ 318 $ 3,603 $ 1,782,333 $ 1,785,936 ​ Commercial real estate: other construction & land development ​ 1,059 ​ 854 ​ 16,587 ​ — ​ 18,500 ​ 1,828,257 ​ 1,846,757 ​ Commercial real estate: farmland & commercial ​ 2,435 ​ 219 ​ 186 ​ 186 ​ 2,840 ​ 2,286,468 ​ 2,289,308 ​ Commercial real estate: multifamily ​ 126 ​ — ​ — ​ — ​ 126 ​ 440,918 ​ 441,044 ​ Residential: first lien ​ 2,399 ​ 926 ​ 6,165 ​ 5,890 ​ 9,490 ​ 395,629 ​ 405,119 ​ Residential: junior lien ​ 561 ​ 247 ​ 1,197 ​ 1,197 ​ 2,005 ​ 592,020 ​ 594,025 ​ Consumer ​ 318 ​ 71 ​ 79 ​ 79 ​ 468 ​ 40,127 ​ 40,595 ​ Foreign ​ 478 ​ 180 ​ 568 ​ 568 ​ 1,226 ​ 137,744 ​ 138,970 ​ Total past due loans ​ $ 9,307 ​ $ 3,606 ​ $ 25,345 ​ $ 8,238 ​ $ 38,258 ​ $ 7,503,496 ​ $ 7,541,754 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 90 Days or ​ Total ​ ​ ​ ​ ​ ​ ​ ​ ​ 30 - 59 ​ 60 - 89 ​ 90 Days or ​ greater & ​ Past ​ ​ ​ ​ Total ​ ​ ​ Days ​ Days ​ Greater ​ still accruing ​ Due ​ Current ​ Portfolio ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ $ 3,134 $ 626 $ 1,292 $ 421 $ 5,052 $ 1,287,608 $ 1,292,660 ​ Commercial real estate: other construction & land development ​ 509 ​ 55 ​ — ​ — ​ 564 ​ 2,185,319 ​ 2,185,883 ​ Commercial real estate: farmland & commercial ​ 8,058 ​ 2,031 ​ 54,928 ​ 54,878 ​ 65,017 ​ 1,831,730 ​ 1,896,747 ​ Commercial real estate: multifamily ​ 313 ​ — ​ 165 ​ — ​ 478 ​ 189,952 ​ 190,430 ​ Residential: first lien ​ 3,229 ​ 1,670 ​ 3,660 ​ 3,107 ​ 8,559 ​ 425,342 ​ 433,901 ​ Residential: junior lien ​ 1,112 ​ 477 ​ 1,200 ​ 1,200 ​ 2,789 ​ 703,687 ​ 706,476 ​ Consumer ​ 467 ​ 75 ​ 88 ​ 88 ​ 630 ​ 47,170 ​ 47,800 ​ Foreign ​ 1,347 ​ 3 ​ 11 ​ 11 ​ 1,361 ​ 139,688 ​ 141,049 ​ Total past due loans ​ $ 18,169 ​ $ 4,937 ​ $ 61,344 ​ $ 59,705 ​ $ 84,450 ​ $ 6,810,496 ​ $ 6,894,946 ​
Summary of the loan portfolio by credit quality indicator, by loan class	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 2017 2016 Prior Total ​ ​ ​ (Dollars in Thousands) ​ Balance at December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 1,168,671 ​ $ 240,869 ​ $ 145,670 ​ $ 85,434 ​ $ 13,901 ​ $ 10,000 ​ $ 1,664,545 ​ Special Review ​ ​ 75,638 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 75,638 ​ Watch List - Pass ​ ​ 39,886 ​ ​ 11 ​ ​ — ​ ​ 3 ​ ​ — ​ ​ 17 ​ ​ 39,917 ​ Watch List - Substandard ​ ​ 3,360 ​ ​ 683 ​ ​ 289 ​ ​ — ​ ​ 315 ​ ​ — ​ ​ 4,647 ​ Watch List - Doubtful ​ ​ 777 ​ ​ 161 ​ ​ 92 ​ ​ 159 ​ ​ — ​ ​ — ​ ​ 1,189 ​ Total Commercial ​ $ 1,288,332 ​ $ 241,724 ​ $ 146,051 ​ $ 85,596 ​ $ 14,216 ​ $ 10,017 ​ $ 1,785,936 ​ Commercial real estate: other construction & land development ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 773,165 ​ $ 576,707 ​ $ 320,308 ​ $ 78,174 ​ $ 10,534 ​ $ 3,343 ​ $ 1,762,231 ​ Special Review ​ ​ 20,828 ​ ​ 21,650 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 42,478 ​ Watch List - Pass ​ ​ 23,101 ​ ​ 1,451 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 24,552 ​ Watch List - Doubtful ​ ​ 16,702 ​ ​ 794 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 17,496 ​ Total Commercial real estate: other construction & land development ​ $ 833,796 ​ $ 600,602 ​ $ 320,308 ​ $ 78,174 ​ $ 10,534 ​ $ 3,343 ​ $ 1,846,757 ​ Commercial real estate: farmland & commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 884,070 ​ $ 373,993 ​ $ 386,268 ​ $ 189,639 ​ $ 202,500 ​ $ 116,729 ​ $ 2,153,199 ​ Special Review ​ ​ 3,041 ​ ​ — ​ ​ 4,758 ​ ​ 177 ​ ​ 3,218 ​ ​ — ​ ​ 11,194 ​ Watch List - Pass ​ ​ 61,637 ​ ​ 942 ​ ​ 277 ​ ​ 80 ​ ​ — ​ ​ — ​ ​ 62,936 ​ Watch List - Substandard ​ ​ 53,809 ​ ​ 4,986 ​ ​ — ​ ​ 2,269 ​ ​ 475 ​ ​ 1 ​ ​ 61,540 ​ Watch List - Doubtful ​ ​ — ​ ​ 202 ​ ​ — ​ ​ — ​ ​ — ​ ​ 237 ​ ​ 439 ​ Total Commercial real estate: farmland & commercial ​ $ 1,002,557 ​ $ 380,123 ​ $ 391,303 ​ $ 192,165 ​ $ 206,193 ​ $ 116,967 ​ $ 2,289,308 ​ Commercial real estate: multifamily ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 74,577 ​ $ 208,356 ​ $ 82,818 ​ $ 64,110 ​ $ 6,801 ​ $ 4,248 ​ $ 440,910 ​ Watch List - Doubtful ​ ​ 134 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 134 ​ Total Commercial real estate: multifamily ​ $ 74,711 ​ $ 208,356 ​ $ 82,818 ​ $ 64,110 ​ $ 6,801 ​ $ 4,248 ​ $ 441,044 ​ Residential: first lien ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 81,004 ​ $ 62,165 ​ $ 72,299 ​ $ 54,593 ​ $ 29,250 ​ $ 105,463 ​ $ 404,774 ​ Watch List - Pass ​ ​ — ​ ​ 14 ​ ​ 131 ​ ​ — ​ ​ — ​ ​ — ​ ​ 145 ​ Watch List - Substandard ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 49 ​ ​ — ​ ​ 49 ​ Watch List - Doubtful ​ ​ 86 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 65 ​ ​ 151 ​ Total Residential: first lien ​ $ 81,090 ​ $ 62,179 ​ $ 72,430 ​ $ 54,593 ​ $ 29,299 ​ $ 105,528 ​ $ 405,119 ​ Residential: junior lien ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 196,308 ​ $ 108,276 ​ $ 61,636 ​ $ 75,056 ​ $ 56,705 ​ $ 94,454 ​ $ 592,435 ​ Special Review ​ ​ 740 ​ ​ — ​ ​ — ​ ​ 812 ​ ​ — ​ ​ — ​ ​ 1,552 ​ Watch List- Doubtful ​ ​ — ​ ​ — ​ ​ 38 ​ ​ — ​ ​ — ​ ​ — ​ ​ 38 ​ Total Residential: junior lien ​ $ 197,048 ​ $ 108,276 ​ $ 61,674 ​ $ 75,868 ​ $ 56,705 ​ $ 94,454 ​ $ 594,025 ​ Consumer ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 30,910 ​ $ 7,159 ​ $ 875 ​ $ 225 ​ $ 55 ​ $ 1,371 ​ $ 40,595 ​ Total Consumer ​ $ 30,910 ​ $ 7,159 ​ $ 875 ​ $ 225 ​ $ 55 ​ $ 1,371 ​ $ 40,595 ​ Foreign ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 93,236 ​ $ 19,092 ​ $ 11,572 ​ $ 6,192 ​ $ 3,533 ​ $ 5,345 ​ $ 138,970 ​ Total Foreign ​ $ 93,236 ​ $ 19,092 ​ $ 11,572 ​ $ 6,192 ​ $ 3,533 ​ $ 5,345 ​ $ 138,970 ​ Total Loans ​ $ 3,601,680 ​ $ 1,627,511 ​ $ 1,087,031 ​ $ 556,923 ​ $ 327,336 ​ $ 341,273 ​ $ 7,541,754 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ ​ ​ ​ Special ​ Watch ​ Watch List— ​ Watch List— ​ ​ ​ ​ Pass ​ Review ​ List—Pass ​ Substandard ​ Impaired ​ ​ ​ ​ ​ ​ ​ (Dollars in Thousands) ​ ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial $ 1,228,110 $ 569 $ 39 $ 62,007 $ 1,935 ​ ​ Commercial real estate: other construction & land development ​ 2,090,370 ​ 18,721 ​ 41,949 ​ 33,905 ​ 938 ​ ​ Commercial real estate: farmland & commercial ​ 1,710,446 ​ 13,184 ​ 20,183 ​ 151,726 ​ 1,208 ​ ​ Commercial real estate: multifamily ​ 190,265 ​ — ​ — ​ — ​ 165 ​ ​ Residential: first lien ​ 426,546 ​ 253 ​ 144 ​ 680 ​ 6,278 ​ ​ Residential: junior lien ​ 704,958 ​ 826 ​ — ​ — ​ 692 ​ ​ Consumer ​ 46,605 ​ — ​ — ​ — ​ 1,195 ​ ​ Foreign ​ 140,785 ​ — ​ — ​ — ​ 264 ​ ​ Total ​ $ 6,538,085 ​ $ 33,553 ​ $ 62,315 ​ $ 248,318 ​ $ 12,675 ​ ​

Bank Premises and Equipment (Ta

Bank Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2020
Summary of bank premises and equipment, by asset classification	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Estimated ​ ​ ​ ​ ​ ​ ​ ​ useful lives ​ 2020 ​ 2019 ​ ​ ​ ​ ​ ​ ​ (Dollars in Thousands) Bank buildings and improvements 5 - 39 years $ 577,656 $ 573,257 ​ Furniture, equipment and vehicles 1 - 20 years ​ 311,313 ​ 313,880 ​ Land ​ ​ ​ ​ ​ ​ 117,848 ​ 118,099 ​ Less: accumulated depreciation ​ ​ ​ ​ ​ ​ (526,939) ​ (498,641) ​ Bank premises and equipment, net ​ ​ ​ ​ ​ ​ $ 479,878 ​ $ 506,595 ​

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2020
Schedule of the entity's identified intangible assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Carrying ​ Accumulated ​ ​ ​ ​ ​ Amount ​ Amortization ​ Net ​ ​ (Dollars in Thousands) December 31, 2020: ​ ​ ​ ​ Core deposit premium ​ $ 58,675 ​ $ 58,675 ​ $ — ​ Identified intangible (contract rights) ​ 2,022 ​ 2,022 ​ — ​ Total identified intangibles ​ $ 60,697 ​ $ 60,697 ​ $ — ​ December 31, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Core deposit premium ​ $ 58,675 ​ $ 58,675 ​ $ — ​ Identified intangible (contract rights) ​ 2,022 ​ 2,022 ​ — ​ Total identified intangibles ​ $ 60,697 ​ $ 60,697 ​ $ — ​

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2020
Schedule of deposits and related interest expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 ​ ​ (Dollars in Thousands) Deposits: ​ ​ ​ Demand - non-interest bearing ​ ​ ​ ​ ​ ​ ​ Domestic ​ $ 3,781,277 ​ $ 2,815,835 ​ Foreign ​ 934,537 ​ 730,070 ​ Total demand non-interest bearing ​ 4,715,814 ​ 3,545,905 ​ Savings and interest bearing demand ​ ​ ​ ​ ​ ​ ​ Domestic ​ 2,919,314 ​ 2,477,668 ​ Foreign ​ 933,191 ​ 790,161 ​ Total savings and interest bearing demand ​ 3,852,505 ​ 3,267,829 ​ Time, certificates of deposit $100,000 or more ​ ​ ​ ​ ​ ​ ​ Domestic ​ 797,692 ​ 636,005 ​ Foreign ​ 822,387 ​ 827,031 ​ Less than $100,000 ​ ​ ​ ​ ​ ​ ​ Domestic ​ 291,473 ​ 302,620 ​ Foreign ​ 241,989 ​ 246,644 ​ Total time, certificates of deposit ​ 2,153,541 ​ 2,012,300 ​ Total deposits ​ $ 10,721,860 ​ $ 8,826,034 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 ​ 2018 ​ ​ (Dollars in Thousands) Interest expense: ​ ​ ​ ​ Savings and interest bearing demand ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic $ 5,098 ​ $ 13,462 ​ $ 11,029 ​ Foreign ​ 1,260 ​ 2,917 ​ 1,735 ​ Total savings and interest bearing demand ​ 6,358 ​ 16,379 ​ 12,764 ​ Time, certificates of deposit $100,000 or more ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ 8,827 ​ 7,804 ​ 4,741 ​ Foreign ​ 7,536 ​ 9,407 ​ 5,798 ​ Less than $100,000 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ 1,781 ​ 2,232 ​ 1,589 ​ Foreign ​ 1,086 ​ 1,527 ​ 968 ​ Total time, certificates of deposit ​ 19,230 ​ 20,970 ​ 13,096 ​ Total interest expense on deposits ​ $ 25,588 ​ $ 37,349 ​ $ 25,860 ​ ​
Scheduled maturities of time deposits	Scheduled maturities of time deposits as of December 31, 2020 were as follows: ​ ​ ​ ​ ​ ​ ​ Total ​ ​ (in thousands) 2021 ​ $ 1,971,433 ​ 2022 ​ 141,388 ​ 2023 ​ 28,781 ​ 2024 ​ 11,205 ​ 2025 ​ 681 ​ Thereafter ​ 53 ​ Total ​ $ 2,153,541 ​
Scheduled maturities of time deposits in amounts of $100,000 or more	​ ​ ​ ​ ​ ​ ​ Total ​ ​ (in thousands) Due within 3 months or less $ 606,807 Due after 3 months and within 6 months ​ 385,859 Due after 6 months and within 12 months ​ 498,626 Due after 12 months ​ 129,792 ​ ​ $ 1,621,084

Securities Sold Under Repurch_2

Securities Sold Under Repurchase Agreements (Tables)	12 Months Ended
	Dec. 31, 2020
Schedule of repurchase agreements	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Collateral Securities ​ Repurchase Borrowing ​ ​ Book Value of ​ Fair Value of ​ Balance of ​ Weighted Average ​ ​ Securities Sold ​ Securities Sold ​ Liability ​ Interest Rate ​ ​ (Dollars in Thousands) December 31, 2020 term: ​ ​ ​ ​ Overnight agreements ​ $ 506,020 ​ $ 507,164 ​ $ 416,757 0.13 % 1 to 29 days ​ — ​ — ​ — — ​ 30 to 90 days ​ — ​ — ​ — — ​ Over 90 days ​ 11,684 ​ 11,641 ​ 11,391 0.43 ​ Total ​ $ 517,704 ​ $ 518,805 ​ $ 428,148 0.14 % December 31, 2019 term: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Overnight agreements ​ $ 317,107 ​ $ 318,397 ​ $ 225,243 0.87 % 1 to 29 days ​ — ​ — ​ — — ​ 30 to 90 days ​ — ​ — ​ — — ​ Over 90 days ​ 11,564 ​ 11,529 ​ 11,293 1.28 ​ Total ​ $ 328,671 ​ $ 329,926 ​ $ 236,536 0.89 %

Other Borrowed Funds (Tables)

Other Borrowed Funds (Tables)	12 Months Ended
	Dec. 31, 2020
Schedule of other borrowed funds	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ 2020 ​ 2019 ​ ​ (Dollars in Thousands) Federal Home Loan Bank advances—short-term ​ ​ ​ Balance at year end ​ $ — ​ $ 190,000 ​ Rate on balance outstanding at year end ​ — % 1.48 % Average daily balance ​ $ 110,776 ​ $ 190,431 ​ Average rate ​ 1.19 % 2.60 % Maximum amount outstanding at any month end ​ $ 292,000 ​ $ 371,775 ​ Federal Home Loan Bank advances—long-term (1) ​ ​ ​ ​ ​ ​ ​ Balance at year end ​ $ 436,327 ​ $ 436,511 ​ Rate on balance outstanding at year end ​ 1.73 % 1.73 % Average daily balance ​ $ 436,411 ​ $ 436,593 ​ Average rate ​ 1.71 % 1.71 % Maximum amount outstanding at any month end ​ $ 436,495 ​ $ 436,675 ​ ​ (1) Long-term advances at December 31, 2020 and December 31, 2019 consisted of both amortizing and non-amortizing advances. The non-amortizing advances mature in the following increments: $75,000,000 in July 2028, $100,000,000 in March 2033 and $250,000,000 in August 2033 and are callable by the FHLB on a quarterly basis. Two amortizing advances are outstanding at December 31, 2020 in the amounts of $3,091,000 and $8,236,000 and mature in December 2033 and November 2033, respectively. The amortization on the amortizing long-term advances totals approximately $189,000 , $194,000 , $199,000 , $204,000 and $210,000 for the years ending December 31, 2021, December 31, 2022, December 31, 2023, December 31, 2024 and December 31, 2025, respectively.

Junior Subordinated Deferrabl_2

Junior Subordinated Deferrable Interest Debentures (Tables)	12 Months Ended
	Dec. 31, 2020
Junior subordinated interest deferrable debentures, major types of business trusts	The following table illustrates key information about each of the Debentures and their interest rates at December 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Junior ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Subordinated ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferrable ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest ​ Repricing ​ Interest ​ Interest ​ ​ ​ Optional ​ ​ ​ Debentures ​ Frequency ​ Rate ​ Rate Index(1) ​ Maturity Date ​ Redemption Date (1) ​ ​ ​ (Dollars in Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Trust VIII ​ $ 25,774 Quarterly 3.29 % LIBOR + 3.05 October 2033 October 2008 ​ Trust IX ​ 41,238 Quarterly 1.85 % LIBOR + 1.62 October 2036 October 2011 ​ Trust X ​ 21,021 Quarterly 1.86 % LIBOR + 1.65 February 2037 February 2012 ​ Trust XI ​ 25,990 Quarterly 1.85 % LIBOR + 1.62 July 2037 July 2012 ​ Trust XII ​ 20,619 Quarterly 1.68 % LIBOR + 1.45 September 2037 September 2012 ​ ​ ​ $ 134,642 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) The Capital Securities may be redeemed in whole or in part on any interest payment date after the Optional Redemption Date.

Earnings per Share ("EPS") (Tab

Earnings per Share ("EPS") (Tables)	12 Months Ended
	Dec. 31, 2020
Schedule of calculation of the basic EPS and the diluted EPS	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net Income ​ Shares ​ Per Share ​ ​ (Numerator) ​ (Denominator) ​ Amount ​ ​ (Dollars in Thousands, ​ ​ Except Per Share Amounts) December 31, 2020: ​ ​ ​ Basic EPS ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income available to common shareholders ​ $ 167,319 63,725,819 ​ $ 2.63 ​ Potential dilutive common shares and warrants ​ — 127,316 ​ ​ ​ ​ Diluted EPS ​ $ 167,319 63,853,135 ​ $ 2.62 ​ December 31, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic EPS ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income available to common shareholders ​ $ 205,104 65,476,606 ​ $ 3.13 ​ Potential dilutive common shares and warrants ​ — 209,078 ​ ​ ​ ​ Diluted EPS ​ $ 205,104 65,685,684 ​ $ 3.12 ​ December 31, 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic EPS ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income available to common shareholders ​ $ 215,931 66,106,580 ​ $ 3.27 ​ Potential dilutive common shares ​ — 527,240 ​ ​ ​ ​ Diluted EPS ​ $ 215,931 66,633,820 ​ $ 3.24 ​

International Operations (Table

International Operations (Tables)	12 Months Ended
	Dec. 31, 2020
Summary of assets attributable to international operations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 ​ ​ (Dollars in Thousands) Loans: ​ ​ ​ Commercial ​ $ 90,177 ​ $ 88,979 ​ Others ​ 48,793 ​ 52,070 ​ ​ ​ 138,970 ​ 141,049 ​ Less allowance for probable loan losses ​ (753) ​ (823) ​ Net loans ​ $ 138,217 ​ $ 140,226 ​ Accrued interest receivable ​ $ 605 ​ $ 743 ​

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Schedule of current and deferred portions of net income tax expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 ​ 2018 ​ ​ (Dollars in Thousands) Current ​ ​ ​ ​ U.S. ​ $ 43,794 ​ $ 48,559 ​ $ 48,144 ​ State ​ 3,709 ​ 2,944 ​ 3,370 ​ Foreign ​ 58 ​ 38 ​ (5) ​ Total current taxes ​ 47,561 ​ 51,541 ​ 51,509 ​ Deferred ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. ​ (2,733) ​ 2,979 ​ 5,130 ​ State ​ (389) ​ 330 ​ 13 ​ Total deferred taxes ​ (3,122) ​ 3,309 ​ 5,143 ​ Total income taxes ​ $ 44,439 ​ $ 54,850 ​ $ 56,652 ​
Schedule of income tax expense differences from the amount computed by applying the U.S. Federal income tax rate to income before income taxes	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 ​ 2018 ​ ​ (Dollars in Thousands) Computed expected tax expense $ 45,218 $ 55,086 $ 57,831 ​ Change in taxes resulting from: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Tax-exempt interest income ​ (2,709) ​ (2,550) ​ (3,101) ​ State tax, net of federal income taxes, tax credit and refunds ​ 2,622 ​ 2,587 ​ 2,673 ​ Resolution of IRS exam ​ ​ ​ — ​ — ​ Other investment income ​ (2,205) ​ (1,480) ​ (1,561) ​ Deferred tax adjustment due to federal tax rate change ​ ​ ​ ​ ​ — ​ ​ (1,618) ​ Net investment in low income housing investments ​ ​ 1,990 ​ ​ 623 ​ ​ 2,518 ​ Other ​ (477) ​ 584 ​ (90) ​ Actual tax expense ​ $ 44,439 ​ $ 54,850 ​ $ 56,652 ​
Schedule of tax effects of temporary difference that give rise to significant portions of the deferred tax assets and deferred tax liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 ​ 2019 ​ ​ (Dollars in Thousands) Deferred tax assets: ​ ​ ​ Loans receivable, principally due to the allowance for probable loan losses ​ $ 21,921 ​ $ 12,050 ​ Other real estate owned ​ 1,183 ​ 2,501 ​ Impairment charges on available-for-sale securities ​ — ​ 1,054 ​ Accrued expenses ​ 81 ​ 98 ​ Other ​ 5,649 ​ 6,019 ​ Total deferred tax assets ​ 28,834 ​ 21,722 ​ Deferred tax liabilities: ​ ​ ​ ​ ​ ​ ​ Bank premises and equipment, principally due to differences on depreciation ​ (12,350) ​ (12,478) ​ Net unrealized gains on available for sale investment securities ​ ​ (5,679) ​ ​ (508) ​ Impairment charges on available-for-sale securities ​ ​ (19) ​ ​ — ​ Identified intangible assets and goodwill ​ (13,807) ​ (13,649) ​ Other ​ (20,551) ​ (18,849) ​ Total deferred tax liabilities ​ (52,406) ​ (45,484) ​ Net deferred tax liability ​ $ (23,572) ​ $ (23,762) ​

Stock Options (Tables)

Stock Options (Tables)	12 Months Ended
	Dec. 31, 2020
Schedule of Black-Scholes-Merton option valuation model assumptions	​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 Expected Life (Years) 7.00 ​ 7.00 ​ Dividend yield 6.04 % 2.93 % Interest rate 0.74 % 1.97 % Volatility 29.04 % 26.97 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Summary of option activity under stock option plans	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ Weighted ​ average ​ ​ ​ ​ ​ ​ ​ ​ average ​ remaining ​ Aggregate ​ ​ ​ Number of ​ exercise ​ contractual ​ intrinsic ​ ​ ​ options ​ price ​ term (years) ​ value ($) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (in Thousands) ​ Options outstanding at December 31, 2019 658,588 ​ $ 27.55 ​ ​ ​ ​ ​ ​ Plus: Options granted 35,000 ​ 18.79 ​ ​ ​ ​ ​ ​ Less: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options exercised 26,010 ​ 20.87 ​ ​ ​ ​ ​ ​ Options expired — ​ — ​ ​ ​ ​ ​ ​ Options forfeited 16,451 ​ 31.94 ​ ​ ​ ​ ​ ​ Options outstanding at December 31, 2020 651,127 ​ 27.24 5.05 ​ $ 6,817 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options fully vested and exercisable at December 31, 2020 409,782 ​ $ 22.98 3.61 ​ $ 5,953 ​
Schedule of other information pertaining to option activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Twelve Months Ended December 31, ​ ​ 2020 ​ 2019 ​ 2018 Weighted average grant date fair value of stock options granted $ 2.46 $ 7.38 $ 11.78 ​ Total fair value of stock options vested ​ $ 1,218,000 ​ $ 1,333,000 ​ $ 1,077,000 ​ Total intrinsic value of stock options exercised ​ $ 356,000 ​ $ 2,373,000 ​ $ 2,045,000 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Financial Instruments with Of_2

Financial Instruments with Off-Statement of Condition Risk and Concentrations of Credit Risk (Tables)	12 Months Ended
	Dec. 31, 2020
Schedule of financial amounts of instruments, whose contract amounts represent credit risks	​ ​ ​ ​ ​ Commitments to extend credit $ 2,354,010,000 Credit card lines ​ 13,579,000 Standby letters of credit ​ 118,381,000 Commercial letters of credit ​ 341,000

Capital Requirements (Tables)

Capital Requirements (Tables)	12 Months Ended
	Dec. 31, 2020
Schedule of the Company's and the bank subsidiaries' actual capital amounts and ratios	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For Capital Adequacy ​ To Be Well-Capitalized ​ ​ ​ ​ ​ ​ ​ Purposes ​ Under Prompt Corrective ​ ​ Actual ​ Phase In Schedule ​ Action Provisions ​ ​ Amount ​ Ratio ​ Amount ​ Ratio ​ Amount ​ Ratio ​ ​ ​ ​ ​ ​ ​ (greater than ​ (greater than ​ (greater than ​ (greater than ​ ​ ​ ​ ​ ​ ​ or equal to) ​ or equal to) ​ or equal to) ​ or equal to) ​ ​ (Dollars in Thousands) As of December 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Common Equity Tier 1 (to Risk Weighted Assets): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 1,874,641 19.05 % $ 688,678 7.000 % ​ N/A N/A ​ International Bank of Commerce, Laredo ​ 1,295,437 18.19 ​ 498,492 7.000 ​ $ 462,885 6.50 % International Bank of Commerce, Oklahoma ​ ​ 207,339 ​ 17.45 ​ ​ 83,150 ​ 7.000 ​ ​ 77,211 ​ 6.50 ​ International Bank of Commerce, Brownsville ​ 189,575 22.18 ​ 59,843 7.000 ​ 55,569 6.50 ​ International Bank of Commerce, Zapata ​ 71,369 34.51 ​ 14,476 7.000 ​ 13,442 6.50 ​ Commerce Bank ​ 93,426 35.64 ​ 18,347 7.000 ​ 17,037 6.50 ​ Total Capital (to Risk Weighted Assets): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 2,105,360 21.40 % $ 1,033,017 10.500 % ​ N/A N/A ​ International Bank of Commerce, Laredo ​ 1,380,685 19.39 ​ 747,737 10.500 ​ $ 712,131 10.00 % International Bank of Commerce, Oklahoma ​ ​ 218,657 ​ 18.41 ​ ​ 124,725 ​ 10.500 ​ ​ 118,786 ​ 10.00 ​ International Bank of Commerce, Brownsville ​ 200,269 23.43 ​ 89,765 10.500 ​ 85,490 10.00 ​ International Bank of Commerce, Zapata ​ 73,510 35.55 ​ 21,714 10.500 ​ 20,680 10.00 ​ Commerce Bank ​ 96,240 36.72 ​ 27,521 10.500 ​ 26,210 10.00 ​ Tier 1 Capital (to Risk Weighted Assets): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 1,992,403 20.25 % $ 836,252 8.500 % N/A N/A ​ International Bank of Commerce, Laredo ​ 1,295,437 18.19 ​ 605,311 8.500 ​ $ 569,705 8.00 % International Bank of Commerce, Oklahoma ​ ​ 207,339 ​ 17.45 ​ ​ 100,968 ​ 8.500 ​ ​ 95,029 ​ 8.00 ​ International Bank of Commerce, Brownsville ​ 189,575 22.18 ​ 72,667 8.500 ​ 68,392 8.00 ​ International Bank of Commerce, Zapata ​ 71,369 34.51 ​ 17,578 8.500 ​ 16,544 8.00 ​ Commerce Bank ​ 93,426 35.64 ​ 22,279 8.500 ​ 20,968 8.00 ​ Tier 1 Capital (to Average Assets): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 1,992,403 14.92 % $ 534,228 4.00 % $ N/A N/A ​ International Bank of Commerce, Laredo ​ 1,295,437 13.11 ​ 395,289 4.00 ​ 494,112 5.00 % International Bank of Commerce, Oklahoma ​ ​ 207,339 ​ 12.98 ​ ​ 63,879 ​ 4.00 ​ ​ 79,848 ​ 5.00 ​ International Bank of Commerce, Brownsville ​ 189,575 14.55 ​ 52,101 4.00 ​ 65,127 5.00 ​ International Bank of Commerce, Zapata ​ 71,369 16.52 ​ 17,277 4.00 ​ 21,596 5.00 ​ Commerce Bank ​ 93,426 16.69 ​ 22,394 4.00 ​ 27,993 5.00 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ To Be Well-Capitalized ​ ​ ​ ​ ​ ​ ​ For Capital Adequacy ​ ​ Under Prompt Corrective ​ ​ Actual ​ Purposes ​ ​ Action Provisions ​ ​ Amount ​ Ratio ​ Amount ​ Ratio ​ ​ Amount Ratio ​ ​ ​ ​ ​ ​ ​ (greater than ​ (greater than ​ (greater than ​ (greater than ​ ​ ​ ​ ​ ​ ​ or equal to) ​ or equal to) ​ or equal to) ​ or equal to) ​ ​ (Dollars in Thousands) As of December 31, 2019: ​ ​ ​ ​ Common Equity Tier 1 (to Risk Weighted Assets): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 1,833,174 18.58 % $ 690,746 7.000 % ​ N/A N/A ​ International Bank of Commerce, Laredo ​ 1,268,078 18.23 ​ 486,950 7.000 ​ $ 452,168 6.50 % International Bank of Commerce, Oklahoma ​ ​ 201,202 ​ 16.91 ​ ​ 83,303 ​ 7.000 ​ ​ 77,353 ​ 6.50 ​ International Bank of Commerce, Brownsville ​ 185,112 22.70 ​ 57,084 7.000 ​ 53,006 6.50 ​ International Bank of Commerce, Zapata ​ 72,402 36.46 ​ 13,902 7.000 ​ 12,909 6.50 ​ Commerce Bank ​ 91,239 34.83 ​ 18,336 7.000 ​ 17,026 6.50 ​ Total Capital (to Risk Weighted Assets): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 2,018,488 20.46 % $ 1,036,118 10.500 % ​ N/A N/A % International Bank of Commerce, Laredo ​ 1,315,453 18.91 ​ 730,425 10.500 ​ $ 695,643 10.00 ​ International Bank of Commerce, Oklahoma ​ ​ 206,807 ​ 17.38 ​ ​ 124,955 ​ 10.500 ​ ​ 119,004 ​ 10.00 ​ International Bank of Commerce, Brownsville ​ 192,417 23.60 ​ 85,626 10.500 ​ 81,548 10.00 ​ International Bank of Commerce, Zapata ​ 74,737 37.63 ​ 20,853 10.500 ​ 19,860 10.00 ​ Commerce Bank ​ 93,396 35.65 ​ 27,504 10.500 ​ 26,195 10.00 ​ Tier 1 Capital (to Risk Weighted Assets): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ % Consolidated ​ $ 1,953,711 19.80 % $ 838,762 8.500 % N/A N/A ​ International Bank of Commerce, Laredo ​ 1,268,078 18.23 ​ 591,296 8.500 ​ $ 556,514 8.00 ​ International Bank of Commerce, Oklahoma ​ ​ 201,202 ​ 16.91 ​ ​ 101,154 ​ 8.500 ​ ​ 95,203 ​ 8.00 ​ International Bank of Commerce, Brownsville ​ 185,112 22.70 ​ 69,316 8.500 ​ 65,239 8.00 ​ International Bank of Commerce, Zapata ​ 72,402 36.46 ​ 16,881 8.500 ​ 15,888 8.00 ​ Commerce Bank ​ 91,239 34.83 ​ 22,265 8.500 ​ 20,956 8.00 % Tier 1 Capital (to Average Assets): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated ​ $ 1,953,711 16.65 % $ 469,267 4.00 % $ N/A N/A ​ International Bank of Commerce, Laredo ​ 1,268,078 15.21 ​ 333,576 4.00 ​ 416,970 5.00 ​ International Bank of Commerce, Oklahoma ​ ​ 201,202 ​ 14.79 ​ ​ 54,406 ​ 4.00 ​ ​ 68,007 ​ 5.00 ​ International Bank of Commerce, Brownsville ​ 185,112 17.41 ​ 42,529 4.00 ​ 53,161 5.00 ​ International Bank of Commerce, Zapata ​ 72,402 19.08 ​ 15,179 4.00 ​ 18,974 5.00 ​ Commerce Bank ​ 91,239 18.18 ​ 20,073 4.00 ​ 25,091 5.00 ​

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2020
Assets and liabilities measured at fair value on a recurring basis	The following table represents financial instruments reported on the consolidated statements of condition at their fair value as of December 31, 2020 by level within the fair value measurement hierarchy. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at ​ ​ ​ ​ ​ ​ Reporting Date Using ​ ​ ​ ​ ​ ​ (in Thousands) ​ ​ ​ ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Prices in ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Active ​ Significant ​ ​ ​ ​ ​ ​ Assets/Liabilities ​ Markets for ​ Other ​ Significant ​ ​ ​ Measured at ​ Identical ​ Observable ​ Unobservable ​ ​ ​ Fair Value ​ Assets ​ Inputs ​ Inputs ​ ​ ​ December 31, 2020 ​ (Level 1) ​ (Level 2) ​ (Level 3) ​ Measured on a recurring basis: ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Available for sale debt securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential mortgage-backed securities ​ $ 3,029,954 ​ $ — ​ $ 3,029,954 ​ $ — ​ States and political subdivisions ​ 50,814 ​ — ​ 50,814 ​ — ​ Equity Securities ​ 6,202 ​ 6,202 ​ — ​ — ​ ​ ​ $ 3,086,970 ​ $ 6,202 ​ $ 3,080,768 ​ $ — ​ ​ The following table represents financial instruments reported on the consolidated balance sheets at their fair value as of December 31, 2019 by level within the fair value measurement hierarchy. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at ​ ​ ​ ​ ​ ​ Reporting Date Using ​ ​ ​ ​ ​ ​ (in Thousands) ​ ​ ​ ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Prices in ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Active ​ Significant ​ ​ ​ ​ ​ ​ Assets/Liabilities ​ Markets for ​ Other ​ Significant ​ ​ ​ Measured at ​ Identical ​ Observable ​ Unobservable ​ ​ ​ Fair Value ​ Assets ​ Inputs ​ Inputs ​ ​ ​ December 31, 2019 ​ (Level 1) ​ (Level 2) ​ (Level 3) ​ Measured on a recurring basis: ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Available for sale securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Residential mortgage - backed securities ​ $ 3,285,548 ​ $ — ​ $ 3,285,548 ​ $ — ​ States and political subdivisions ​ 93,375 ​ — ​ 93,375 ​ — ​ Equity Securities ​ 6,095 ​ 6,095 ​ — ​ — ​ ​ ​ $ 3,385,018 ​ $ 6,095 ​ $ 3,378,923 ​ $ — ​
Assets measured at fair value on a non-recurring basis	The following table represents financial instruments measured at fair value on a non-recurring basis as of and for the period ended December 31, 2020 by level within the fair value measurement hierarchy: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at Reporting ​ ​ ​ ​ ​ ​ ​ ​ Date Using ​ ​ ​ ​ ​ ​ ​ ​ (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets/Liabilities ​ Prices in ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Measured at ​ Active ​ Significant ​ ​ ​ ​ ​ ​ ​ ​ Fair Value ​ Markets for ​ Other ​ Significant ​ Net Provision ​ ​ Period ended ​ Identical ​ Observable ​ Unobservable ​ (Credit) ​ ​ December 31, ​ Assets ​ Inputs ​ Inputs ​ During ​ ​ 2020 ​ (Level 1) ​ (Level 2) ​ (Level 3) ​ Period Measured on a non-recurring basis: ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Watch-List doubtful loans ​ $ 393 ​ $ — ​ $ — ​ $ 393 ​ $ (86) Other real estate owned ​ 6,241 ​ — ​ — ​ 6,241 ​ 1,539 ​ The following table represents financial instruments measured at fair value on a non-recurring basis as of and for the year ended December 31, 2019 by level within the fair value measurement hierarchy: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at Reporting ​ ​ ​ ​ ​ ​ ​ ​ Date Using ​ ​ ​ ​ ​ ​ ​ ​ (in thousands) ​ ​ ​ ​ ​ ​ ​ ​ Quoted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets/Liabilities ​ Prices in ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Measured at ​ Active ​ Significant ​ ​ ​ ​ ​ ​ ​ ​ Fair Value ​ Markets ​ Other ​ Significant ​ Net (Credit) ​ ​ Year ended ​ for Identical ​ Observable ​ Unobservable ​ Provision ​ ​ December 31, ​ Assets ​ Inputs ​ Inputs ​ During ​ ​ 2019 ​ (Level 1) ​ (Level 2) ​ (Level 3) ​ Period Measured on a non-recurring basis: ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Impaired loans ​ $ 826 ​ $ — ​ $ — ​ $ 826 ​ $ 43 Other real estate owned ​ 21,614 ​ — ​ — ​ 21,614 ​ 322 Equity investment without a readily determinable fair value ​ ​ 28,166 ​ ​ — ​ ​ — ​ ​ 28,166 ​ ​ 4,775

International Bancshares Corp_4

International Bancshares Corporation (Parent Company Only) Financial Information Statements of Condition (Tables)	12 Months Ended
	Dec. 31, 2020
Schedule of condensed statements of condition of Parent Company	(Dollars in Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 ASSETS ​ ​ ​ ​ ​ ​ ​ Cash ​ $ 66,252 ​ $ 24,290 ​ Other investments ​ 77,661 ​ 106,284 ​ Net loans ​ 11,950 ​ 12,100 ​ Investment in subsidiaries ​ 2,167,516 ​ 2,120,391 ​ Goodwill ​ ​ 3,365 ​ ​ 3,365 ​ Other assets ​ — ​ 264 ​ Total assets ​ $ 2,326,744 ​ $ 2,266,694 ​ LIABILITIES AND SHAREHOLDERS’ EQUITY ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ Junior subordinated deferrable interest debentures ​ $ 134,642 ​ $ 134,642 ​ Due to IBC Trading ​ 21 ​ 21 ​ Other liabilities ​ 14,083 ​ 13,978 ​ Total liabilities ​ 148,746 ​ 148,641 ​ Shareholders’ equity: ​ ​ ​ ​ ​ ​ ​ Common shares ​ 96,241 ​ 96,215 ​ Surplus ​ 149,334 ​ 148,075 ​ Retained earnings ​ 2,289,626 ​ 2,200,568 ​ Accumulated other comprehensive income (loss) ​ 20,825 ​ 2,345 ​ ​ ​ 2,556,026 ​ 2,447,203 ​ Less cost of shares in treasury ​ (378,028) ​ (329,150) ​ Total shareholders’ equity ​ 2,177,998 ​ 2,118,053 ​ Total liabilities and shareholders’ equity ​ $ 2,326,744 ​ $ 2,266,694 ​

International Bancshares Corp_5

International Bancshares Corporation (Parent Company Only) Financial Information Statements of Income (Tables)	12 Months Ended
	Dec. 31, 2020
Schedule of condensed statements of income of Parent Company	(Dollars in Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 Income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Dividends from subsidiaries ​ $ 130,950 ​ $ 127,750 ​ $ 105,000 ​ Interest income on notes receivable ​ 357 ​ 922 ​ — ​ Interest income on other investments ​ (1,126) ​ (514) ​ 8,208 ​ Other ​ 5 ​ 18 ​ 1,988 ​ Total income ​ 130,186 ​ 128,176 ​ 115,196 ​ Expenses: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Interest expense (Debentures) ​ 3,832 ​ 6,435 ​ 6,989 ​ Provision for credit loss ​ ​ 27 ​ ​ — ​ ​ — ​ Other ​ 1,988 ​ 2,749 ​ 2,930 ​ Total expenses ​ 5,847 ​ 9,184 ​ 9,919 ​ Income before federal income taxes and equity in undistributed net income of subsidiaries ​ 124,339 ​ 118,992 ​ 105,277 ​ Income tax expense ​ (1,339) ​ (1,878) ​ 481 ​ Income before equity in undistributed net income of subsidiaries ​ 125,678 ​ 120,870 ​ 104,796 ​ Equity in undistributed net income of subsidiaries ​ 41,641 ​ 84,234 ​ 111,135 ​ Net income ​ $ 167,319 ​ $ 205,104 ​ $ 215,931 ​

International Bancshares Corp_6

International Bancshares Corporation (Parent Company Only) Financial Information Statements of Cash Flows (Tables)	12 Months Ended
	Dec. 31, 2020
Schedule of condensed statements of cash flows of Parent Company	(Dollars in Thousands) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 2018 Operating activities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income ​ $ 167,319 ​ $ 205,104 ​ $ 215,931 ​ Adjustments to reconcile net income to net cash provided by operating activities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Provision for credit loss ​ ​ 27 ​ ​ — ​ ​ — ​ Unrealized loss (gain) on equity securities with readily determinable fair values ​ ​ 22 ​ ​ (16) ​ ​ 330 ​ Stock compensation expense ​ 743 ​ 980 ​ 1,035 ​ Increase (decrease) in other liabilities ​ 2,467 ​ (58) ​ (1,479) ​ Equity in undistributed net income of subsidiaries ​ (41,641) ​ (84,234) ​ (111,135) ​ Net cash provided by operating activities ​ 128,937 ​ 121,776 ​ 104,682 ​ Investing activities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net increase in notes receivable ​ — ​ (12,100) ​ — ​ (Decrease) increase in other assets and other investments ​ 31,289 ​ 5,915 ​ (7,891) ​ Net cash provided by (used in) investing activities ​ 31,289 ​ (6,185) ​ (7,891) ​ Financing activities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Redemption of long-term debt ​ — ​ (25,774) ​ — ​ Proceeds from stock transactions ​ 542 ​ 1,923 ​ 1,522 ​ Payments of cash dividends - common ​ (69,928) ​ (68,670) ​ (49,599) ​ Repurchase of outstanding common stock warrant ​ — ​ — ​ (29,005) ​ Purchase of treasury stock ​ (48,878) ​ (17,845) ​ (19,042) ​ Net cash used in financing activities ​ (118,264) ​ (110,366) ​ (96,124) ​ Increase in cash ​ 41,962 ​ 5,225 ​ 667 ​ Cash at beginning of year ​ 24,290 ​ 19,065 ​ 18,398 ​ Cash at end of year ​ $ 66,252 ​ $ 24,290 ​ $ 19,065 ​

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details)	Jan. 01, 2020USD ($)	Oct. 01, 2019USD ($)	Jun. 30, 2018USD ($)	Dec. 31, 2020USD ($)item	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Jan. 01, 2019USD ($)
Number of insurance-related subsidiaries | item				1
Investment Securities
Number of components in which other-than-temporary impairment is segregated | item				2
Non-Accrual Loans
Period of charge off for past due unsecured consumer loans				90 days
Minimum period that past due unsecured loans outstanding may not be placed on nonaccrual status under special circumstances				90 days
Maximum period of non-consumer loans outstanding that is used to evaluate whether loans should be placed on non-accrual status				90 days
Other Real Estate Owned and Repossessed Assets
Other real estate owned				$ 60,487,300	$ 71,103,000
Repossessed assets					7,137,000
Income Taxes
Percentage of likelihood of realization of recognized tax benefit				50.00%
Liability for unrecognized tax benefits				$ 0	0
Interest expense related to uncertain tax positions				0	0	$ 0
Penalties related to uncertain tax positions				0	0	$ 0
Goodwill and Identified Intangible Assets
Goodwill impairment loss		$ 0
Impairment of identified intangible assets				$ 0
Segments of an Enterprise and Related Information
Number of operating segments | item				1
Number of active operating bank subsidiaries | item				5
New Accounting Standards
One-time reclassification from AOCI to retained earnings, relating to the Tax Cuts and Jobs Act of 2017			$ 5,997,000
Right-of-use asset amortization				$ 1,357,000	1,019,000
Retained Earnings (Accumulated Deficit)				$ 2,289,626,000	$ 2,200,568,000
ASU 2016-02
New Accounting Standards
Right of use asset, statement of Financial Position Location							us-gaap:OtherAssets
Lease liability, statement of Financial Position Location							us-gaap:OtherLiabilities
ASU 2016-02 | Adjusted Balance
New Accounting Standards
Right of use asset							$ 6,400,000
Lease liability							$ 6,400,000
ASU 2016-13 | Adjustment
New Accounting Standards
Percentage of Increase in Allowance for Loan Losses	17.20%
Retained Earnings (Accumulated Deficit)	$ 8,300,000

Investment Securities (Details)

Investment Securities (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Held-to-maturity securities
Amortized cost	$ 3,400,000	$ 2,400,000
Estimated fair value	3,400,000	2,400,000
Carrying Value	3,400,000	2,400,000
Available-for-sale securities
Amortized cost	3,054,289,000	3,376,070,000
Gross unrealized gains	35,832,000
Gross unrealized losses	(9,353,000)
Available for sale debt securities	3,080,768,000	3,378,923,000
Total Amortized cost	3,054,289,000	3,376,070,000
Total Gross unrealized gains		19,467,000
Total Gross unrealized losses		16,614,000
Available for sale debt securities and equity securities	3,080,768,000
Estimate of Fair Value Measurement [Member]
Available-for-sale securities
Available for sale debt securities and equity securities	3,080,768,000	3,378,923,000
Reported Value Measurement [Member]
Available-for-sale securities
Available for sale debt securities and equity securities	3,080,768,000	3,378,923,000
Collateralized Mortgage Backed Securities [Member]
Available-for-sale securities
Amortized cost	3,006,592,000	3,285,623,000
Gross unrealized gains	32,701,000	16,534,000
Gross unrealized losses	(9,339,000)	(16,609,000)
Collateralized Mortgage Backed Securities [Member] | Estimate of Fair Value Measurement [Member]
Available-for-sale securities
Available for sale debt securities	3,029,954,000	3,285,548,000
Collateralized Mortgage Backed Securities [Member] | Reported Value Measurement [Member]
Available-for-sale securities
Available for sale debt securities	3,029,954,000	3,285,548,000
US Government Corporations and Agencies Securities [Member]
Available-for-sale securities
Available for sale debt securities	371,407,000	571,247,000
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale securities
Available for sale debt securities	2,658,547,000	2,714,301
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities
Amortized cost	47,697,000	90,447,000
Gross unrealized gains	3,131,000	2,933,000
Gross unrealized losses	(14,000)	(5,000)
US States and Political Subdivisions Debt Securities [Member] | Estimate of Fair Value Measurement [Member]
Available-for-sale securities
Available for sale debt securities	50,814,000	93,375,000
US States and Political Subdivisions Debt Securities [Member] | Reported Value Measurement [Member]
Available-for-sale securities
Available for sale debt securities	50,814,000	93,375,000
Other Debt Obligations [Member]
Held-to-maturity securities
Amortized cost	3,400,000	2,400,000
Estimated fair value	3,400,000	2,400,000
Carrying Value	$ 3,400,000	$ 2,400,000

Investment Securities (Contract

Investment Securities (Contractual Maturities and Estimated Fair Values) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Amortized Cost, Rolling Maturity [Abstract]
Due in one year or less, held-to-maturity debt securities amortized cost	$ 1,200,000
Due after one year through five years, held-to-maturity debt securities amortized cost	2,200,000
Amortized cost, held-to-maturity debt securities	3,400,000	$ 2,400,000
Debt Securities, Held-to-maturity, Maturity, Fair Value, Rolling Maturity [Abstract]
Due in one year or less, held-to-maturity debt securities, Estimated fair value	1,200,000
Due after one year through five years, held-to-maturity debt securities, Estimated fair value	2,200,000
Estimated fair value	3,400,000	2,400,000
Available-for-sale debt securities amortized cost disclosures
Due after five years through ten years, available-for-sale debt securities amortized cost	355,000
Due after ten years, available-for-sale debt securities amortized cost	47,342,000
Residential mortgage-backed securities, amortized cost	3,006,592,000
Amortized cost, Available-for-sale securities	3,054,289,000	3,376,070,000
Available for sale debt securities, Estimated Fair Value Disclosures
Due after five years through ten years, available-for-sale debt securities, Estimated Fair Value	356,000
Due after ten years, available-for-sale debt securities, Estimated Fair Value	50,458,000
Residential mortgage-backed securities, Estimated Fair Value	3,029,954,000
Estimated fair value, Available for sale securities	3,080,768,000	3,378,923,000
Available for sale debt securities, Estimated Fair Value Disclosures
Proceeds from sales and calls of available for sale securities	42,350,000	94,585,000	$ 38,175,000
Proceeds from sales and calls of available for sale securities	42,350,000	94,585,000	59,782,000
Proceeds from sales of mortgage-backed securities	0	0	0
Gross gains realized on sales	1,000	3,000	3,000
Gross losses realized on sales	6,000	$ 15,000	$ 144,000
Collateral Pledged
Available-for-sale debt securities amortized cost disclosures
Amortized cost, Available-for-sale securities	1,220,400,000
Available for sale debt securities, Estimated Fair Value Disclosures
Fair value of available for sale investment securities pledged	$ 1,224,268,000

Investment Securities (Fair Val

Investment Securities (Fair Value and Gross Unrealized Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2020
Available for sale:
Fair value, less than 12 months		$ 1,462,232
Marketable securities, less than 12 months	$ 523,797
Unrealized losses, less than 12 Months		(9,339)
Marketable securities, less than 12 Months	(2,274)
Fair value, 12 months or more		757
Marketable securities, 12 months or more	1,448,109
Unrealized losses, 12 Months or More		(14)
Marketable securities, 12 Months or More	(14,340)
Fair value, Total		1,462,989
Marketable securities, Total	1,971,906
Unrealized losses, Total		(9,353)
Marketable securities, Total	16,614
Collateralized Mortgage Backed Securities [Member]
Available for sale:
Fair value, less than 12 months	523,031	1,462,232
Unrealized losses, less than 12 Months	(2,269)	(9,339)
Fair value, 12 months or more	1,448,109
Unrealized losses, 12 Months or More	(14,340)
Fair value, Total	1,971,140	1,462,232
Unrealized losses, Total	(16,609)	(9,339)
US States and Political Subdivisions Debt Securities [Member]
Available for sale:
Fair value, less than 12 months	766
Unrealized losses, less than 12 Months	(5)
Fair value, 12 months or more		757
Unrealized losses, 12 Months or More		(14)
Fair value, Total	766	757
Unrealized losses, Total	$ (5)	$ (14)

Investment Securities (Unrealiz

Investment Securities (Unrealized and realized gains and losses recognized in net income on equity securities ) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Investment Securities
Equity Securities	$ 6,202,000	$ 6,095,000
Summary of unrealized and realized gains and losses recognized in net income on equity securities
Net gains (losses) recognized during the period on equity securities	107,000	158,000	$ (388,000)
Unrealized gain on equity securities with readily determinable fair values	$ 107,000	$ 158,000	$ (388,000)

Loans (Details)

Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Summary of loans, by loan type
Total loans	$ 7,541,754	$ 6,894,946
Commercial, financial and agricultural
Summary of loans, by loan type
Total loans	4,516,288	3,379,837
Real estate - mortgage
Summary of loans, by loan type
Total loans	999,144	1,140,377
Commercial Real Estate Portfolio Segment [Member]
Summary of loans, by loan type
Total loans	1,846,757	2,185,883
Consumer
Summary of loans, by loan type
Total loans	40,595	47,800
Foreign
Summary of loans, by loan type
Total loans	$ 138,970	$ 141,049

Allowance for Credit Losses (By

Allowance for Credit Losses (By Loan Class) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowance for Credit Losses
Balance at the beginning of the period		$ 61,384	$ 60,278	$ 61,384	$ 67,687
Losses charged to allowance			(9,574)	(22,928)	(15,125)
Recoveries credited to allowance			2,629	2,979	2,710
Net (losses) recoveries charged to allowance			(6,945)	(19,949)	(12,415)
Provision charged (credited) to operations			45,379	18,843	6,112
Balance at the end of the period			109,059	60,278	61,384
Nonperforming Financing Receivable [Member]
Allowance for Credit Losses
Provision charged (credited) to operations	$ (9,500)	(9,500)
ASU 2016-13
Allowance for Credit Losses
Balance at the beginning of the period			10,347
Balance at the end of the period				10,347
Commercial, financial and agricultural | Domestic | Commercial Loan [Member]
Allowance for Credit Losses
Balance at the beginning of the period		12,596	11,145	12,596	27,905
Losses charged to allowance			(8,936)	(14,412)	(14,220)
Recoveries credited to allowance			2,191	2,196	1,981
Net (losses) recoveries charged to allowance			(6,745)	(12,216)	(12,239)
Provision charged (credited) to operations			13,261	10,765	(3,070)
Balance at the end of the period			21,908	11,145	12,596
Commercial, financial and agricultural | Domestic | Commercial Loan [Member] | ASU 2016-13
Allowance for Credit Losses
Balance at the beginning of the period			4,247
Balance at the end of the period				4,247
Commercial, financial and agricultural | Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member]
Allowance for Credit Losses
Balance at the beginning of the period		19,353	16,533	19,353	16,663
Losses charged to allowance			(55)		(70)
Recoveries credited to allowance			117		246
Net (losses) recoveries charged to allowance			62		176
Provision charged (credited) to operations			17,697		2,514
Balance at the end of the period			30,000	16,533	19,353
Commercial, financial and agricultural | Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] | ASU 2016-13
Allowance for Credit Losses
Balance at the beginning of the period			(4,292)
Balance at the end of the period				(4,292)
Commercial, financial and agricultural | Domestic | Commercial Real Estate Multifamily Receivable [Member]
Allowance for Credit Losses
Balance at the beginning of the period		1,808	1,786	1,808	1,109
Provision charged (credited) to operations			3,620	(22)	699
Balance at the end of the period			5,051	1,786	1,808
Commercial, financial and agricultural | Domestic | Commercial Real Estate Multifamily Receivable [Member] | ASU 2016-13
Allowance for Credit Losses
Balance at the beginning of the period			(355)
Balance at the end of the period				(355)
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development
Allowance for Credit Losses
Balance at the beginning of the period		15,123	18,152	15,123	11,675
Losses charged to allowance			(19)	(39)	(1)
Recoveries credited to allowance			35	113	25
Net (losses) recoveries charged to allowance			16	74	24
Provision charged (credited) to operations			6,053	2,955	3,424
Balance at the end of the period			37,612	18,152	15,123
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development | ASU 2016-13
Allowance for Credit Losses
Balance at the beginning of the period			13,391
Balance at the end of the period				13,391
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member]
Allowance for Credit Losses
Balance at the beginning of the period		19,353	16,533	19,353
Losses charged to allowance				(7,353)
Recoveries credited to allowance				318
Net (losses) recoveries charged to allowance				(7,035)
Provision charged (credited) to operations				4,215
Balance at the end of the period				16,533	19,353
Real estate - mortgage | Domestic | Residential First Mortgage Financing Receivable [Member]
Allowance for Credit Losses
Balance at the beginning of the period		3,467	3,762	3,467	2,950
Losses charged to allowance			(160)	(201)	(122)
Recoveries credited to allowance			21	26	36
Net (losses) recoveries charged to allowance			(139)	(175)	(86)
Provision charged (credited) to operations			1,831	470	603
Balance at the end of the period			3,874	3,762	3,467
Real estate - mortgage | Domestic | Residential First Mortgage Financing Receivable [Member] | ASU 2016-13
Allowance for Credit Losses
Balance at the beginning of the period			(1,580)
Balance at the end of the period				(1,580)
Real estate - mortgage | Domestic | Residential Junior Lien
Allowance for Credit Losses
Balance at the beginning of the period		7,719	7,535	7,719	6,103
Losses charged to allowance			(124)	(435)	(347)
Recoveries credited to allowance			186	286	369
Net (losses) recoveries charged to allowance			62	(149)	22
Provision charged (credited) to operations			2,402	(35)	1,594
Balance at the end of the period			9,570	7,535	7,719
Real estate - mortgage | Domestic | Residential Junior Lien | ASU 2016-13
Allowance for Credit Losses
Balance at the beginning of the period			(429)
Balance at the end of the period				(429)
Consumer | Domestic
Allowance for Credit Losses
Balance at the beginning of the period		447	542	447	440
Losses charged to allowance			(280)	(487)	(362)
Recoveries credited to allowance			69	40	43
Net (losses) recoveries charged to allowance			(211)	(447)	(319)
Provision charged (credited) to operations			185	542	326
Balance at the end of the period			291	542	447
Consumer | Domestic | ASU 2016-13
Allowance for Credit Losses
Balance at the beginning of the period			(225)
Balance at the end of the period				(225)
Foreign | Foreign
Allowance for Credit Losses
Balance at the beginning of the period		$ 871	823	871	842
Losses charged to allowance				(1)	(3)
Recoveries credited to allowance			10		10
Net (losses) recoveries charged to allowance			10	(1)	7
Provision charged (credited) to operations			330	(47)	22
Balance at the end of the period			753	823	$ 871
Foreign | Foreign | ASU 2016-13
Allowance for Credit Losses
Balance at the beginning of the period			$ (410)
Balance at the end of the period				$ (410)

Allowance for Credit Losses (Im

Allowance for Credit Losses (Impairment By Loan Class) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	$ 19,447	$ 12,675
Loans Individually Evaluated for Impairment, Allowance	279	365
Loans Collectively Evaluated for Impairment, Recorded Investment	7,522,307	6,882,271
Loans Collectively Evaluated for Impairment, Allowance	108,780	59,913
Commercial, financial and agricultural | Domestic | Commercial Loan [Member]
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	1,189	1,935
Loans Individually Evaluated for Impairment, Allowance	209	249
Loans Collectively Evaluated for Impairment, Recorded Investment	1,784,747	1,290,725
Loans Collectively Evaluated for Impairment, Allowance	21,699	10,895
Commercial, financial and agricultural | Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member]
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	439	1,208
Loans Collectively Evaluated for Impairment, Recorded Investment	2,288,869	1,895,539
Loans Collectively Evaluated for Impairment, Allowance	30,000	16,533
Commercial, financial and agricultural | Domestic | Commercial Real Estate Multifamily Receivable [Member]
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	134	165
Loans Collectively Evaluated for Impairment, Recorded Investment	440,910	190,265
Loans Collectively Evaluated for Impairment, Allowance	5,051	1,786
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	17,496	938
Loans Individually Evaluated for Impairment, Allowance	70	116
Loans Collectively Evaluated for Impairment, Recorded Investment	1,829,261	2,184,945
Loans Collectively Evaluated for Impairment, Allowance	37,542	18,037
Real estate - mortgage | Domestic | Residential First Mortgage Financing Receivable [Member]
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	151	6,278
Loans Collectively Evaluated for Impairment, Recorded Investment	404,968	427,623
Loans Collectively Evaluated for Impairment, Allowance	3,874	3,762
Real estate - mortgage | Domestic | Residential Junior Lien
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	38	692
Loans Collectively Evaluated for Impairment, Recorded Investment	593,987	705,784
Loans Collectively Evaluated for Impairment, Allowance	9,570	7,535
Consumer | Domestic
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment		1,195
Loans Collectively Evaluated for Impairment, Recorded Investment	40,595	46,605
Loans Collectively Evaluated for Impairment, Allowance	291	542
Foreign | Foreign
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment		264
Loans Collectively Evaluated for Impairment, Recorded Investment	138,970	140,785
Loans Collectively Evaluated for Impairment, Allowance	$ 753	$ 823

Allowance for Credit Losses (No

Allowance for Credit Losses (Non-accrual Basis By Loan Class) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Loan loss allowances, financing receivable past due
Non-accrual loans, total	$ 19,822,000	$ 4,886,000	$ 15,791,000
Reduced interest income on non-accrual loans	694,000	340,000	$ 1,119,000
Commercial, financial and agricultural | Domestic | Commercial Loan [Member]
Loan loss allowances, financing receivable past due
Non-accrual loans, total	1,189,000	1,901,000
Commercial, financial and agricultural | Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member]
Loan loss allowances, financing receivable past due
Non-accrual loans, total	439,000	1,208,000
Commercial, financial and agricultural | Domestic | Commercial Real Estate Multifamily Receivable [Member]
Loan loss allowances, financing receivable past due
Non-accrual loans, total	134,000	165,000
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development
Loan loss allowances, financing receivable past due
Non-accrual loans, total	17,496,000	938,000
Real estate - mortgage | Domestic | Residential First Mortgage Financing Receivable [Member]
Loan loss allowances, financing receivable past due
Non-accrual loans, total	526,000	670,000
Real estate - mortgage | Domestic | Residential Junior Lien
Loan loss allowances, financing receivable past due
Non-accrual loans, total	$ 38,000
Consumer | Domestic
Loan loss allowances, financing receivable past due
Non-accrual loans, total		$ 4,000

Allowance for Credit Losses (_2

Allowance for Credit Losses (Impaired Loans) (Details)	12 Months Ended
	Dec. 31, 2019USD ($)	Feb. 22, 2021USD ($)	Feb. 19, 2021USD ($)loan	Dec. 31, 2020USD ($)
Recorded investment:
Total impaired loans with related allowance	$ 636,000
Total impaired loans with no related allowance	12,039,000
Unpaid principal balance:
Total impaired loans with an allowance recorded	685,000
Total impaired loans with no related allowance recorded	13,255,000
Related Allowance	365,000
Average recorded investment:
Total impaired loans with an allowance recorded	645,000
Total impaired loans with no related allowance recorded	52,945,000
Interest Recognized
Total impaired loans with no related allowance recorded	365,000
Total trouble debt restructuring	7,788,000			$ 5,821,000
Amount of loans with some degree of payment deferral		$ 1,011,570,000
Loans	6,894,946,000			7,541,754,000
Period of charge off for past due unsecured commercial loans		90 days
Percentage of loan payments on deferral period		78.00%
Percentage of loan sort of deferral program for relief		13.00%
Paycheck protection program loans (COVID-19 program)
Interest Recognized
Number of loans | loan			3,500
Amount of loans outstanding			$ 395,872,000
Domestic | Commercial Loan [Member]
Interest Recognized
Loans				1,785,936,000
Domestic | Commercial Real Estate: other construction and land development
Interest Recognized
Loans				1,846,757,000
Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member]
Interest Recognized
Loans				2,289,308,000
Domestic | Commercial Real Estate Multifamily Receivable [Member]
Interest Recognized
Loans				441,044,000
Domestic | Residential First Mortgage Financing Receivable [Member]
Interest Recognized
Loans				405,119,000
Domestic | Residential Junior Lien
Interest Recognized
Loans				594,025,000
Commercial, financial and agricultural
Interest Recognized
Loans	3,379,837,000			4,516,288,000
Commercial, financial and agricultural | Domestic | Commercial Loan [Member]
Recorded investment:
Total impaired loans with related allowance	510,000
Total impaired loans with no related allowance	1,425,000
Unpaid principal balance:
Total impaired loans with an allowance recorded	516,000
Total impaired loans with no related allowance recorded	1,516,000
Related Allowance	249,000
Average recorded investment:
Total impaired loans with an allowance recorded	514,000
Total impaired loans with no related allowance recorded	18,794,000
Interest Recognized
Total impaired loans with no related allowance recorded	2,000
Total trouble debt restructuring	32,000
Loans	1,292,660,000			1,785,936,000
Commercial, financial and agricultural | Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member]
Recorded investment:
Total impaired loans with no related allowance	1,208,000
Unpaid principal balance:
Total impaired loans with no related allowance recorded	1,841,000
Average recorded investment:
Total impaired loans with no related allowance recorded	22,357,000
Interest Recognized
Loans	1,896,747,000			2,289,308,000
Commercial, financial and agricultural | Domestic | Commercial Real Estate Multifamily Receivable [Member]
Recorded investment:
Total impaired loans with no related allowance	165,000
Unpaid principal balance:
Total impaired loans with no related allowance recorded	168,000
Average recorded investment:
Total impaired loans with no related allowance recorded	651,000
Interest Recognized
Loans	190,430,000			441,044,000
Commercial Real Estate Portfolio Segment [Member]
Interest Recognized
Loans	2,185,883,000			1,846,757,000
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development
Recorded investment:
Total impaired loans with related allowance	126,000
Total impaired loans with no related allowance	812,000
Unpaid principal balance:
Total impaired loans with an allowance recorded	169,000
Total impaired loans with no related allowance recorded	1,133,000
Related Allowance	116,000
Average recorded investment:
Total impaired loans with an allowance recorded	131,000
Total impaired loans with no related allowance recorded	1,737,000
Interest Recognized
Loans	2,185,883,000			1,846,757,000
Real estate - mortgage
Interest Recognized
Loans	1,140,377,000			999,144,000
Real estate - mortgage | Domestic | Residential First Mortgage Financing Receivable [Member]
Recorded investment:
Total impaired loans with no related allowance	6,278,000
Unpaid principal balance:
Total impaired loans with no related allowance recorded	6,445,000
Average recorded investment:
Total impaired loans with no related allowance recorded	6,988,000
Interest Recognized
Total impaired loans with no related allowance recorded	309,000
Total trouble debt restructuring	5,608,000			4,078,000
Loans	433,901,000			405,119,000
Real estate - mortgage | Domestic | Residential Junior Lien
Recorded investment:
Total impaired loans with no related allowance	692,000
Unpaid principal balance:
Total impaired loans with no related allowance recorded	692,000
Average recorded investment:
Total impaired loans with no related allowance recorded	1,023,000
Interest Recognized
Total impaired loans with no related allowance recorded	42,000
Total trouble debt restructuring	692,000			521,000
Loans	706,476,000			594,025,000
Consumer
Interest Recognized
Loans	47,800,000			40,595,000
Consumer | Domestic
Recorded investment:
Total impaired loans with no related allowance	1,195,000
Unpaid principal balance:
Total impaired loans with no related allowance recorded	1,196,000
Average recorded investment:
Total impaired loans with no related allowance recorded	1,117,000
Interest Recognized
Total trouble debt restructuring	1,192,000			989,000
Loans	47,800,000			40,595,000
Foreign
Interest Recognized
Loans	141,049,000			138,970,000
Foreign | Foreign
Recorded investment:
Total impaired loans with no related allowance	264,000
Unpaid principal balance:
Total impaired loans with no related allowance recorded	264,000
Average recorded investment:
Total impaired loans with no related allowance recorded	278,000
Interest Recognized
Total impaired loans with no related allowance recorded	12,000
Total trouble debt restructuring	264,000			233,000
Loans	$ 141,049,000			$ 138,970,000

Allowance for Credit Losses (Ag

Allowance for Credit Losses (Aging By Loan Class) (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	$ 8,238,000	$ 59,705,000	$ 40,674,000
Past due	38,258,000	84,450,000
Loans, current	7,503,496,000	6,810,496,000
Total loans	7,541,754,000	6,894,946,000
30 to 59 Days
Financing receivable recorded investment
Past due	9,307,000	18,169,000
60 to 89 Days
Financing receivable recorded investment
Past due	3,606,000	4,937,000
90 Days or Greater
Financing receivable recorded investment
Past due	25,345,000	61,344,000
Domestic | Commercial Loan [Member]
Financing receivable recorded investment
Total loans	1,785,936,000
Domestic | Commercial Real Estate: other construction and land development
Financing receivable recorded investment
Total loans	1,846,757,000
Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member]
Financing receivable recorded investment
Total loans	2,289,308,000
Domestic | Commercial Real Estate Multifamily Receivable [Member]
Financing receivable recorded investment
Total loans	441,044,000
Domestic | Residential First Mortgage Financing Receivable [Member]
Financing receivable recorded investment
Total loans	405,119,000
Domestic | Residential Junior Lien
Financing receivable recorded investment
Total loans	594,025,000
Commercial, financial and agricultural
Financing receivable recorded investment
Total loans	4,516,288,000	3,379,837,000
Commercial, financial and agricultural | Domestic | Commercial Loan [Member]
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	318,000	421,000
Past due	3,603,000	5,052,000
Loans, current	1,782,333,000	1,287,608,000
Total loans	1,785,936,000	1,292,660,000
Commercial, financial and agricultural | Domestic | Commercial Loan [Member] | 30 to 59 Days
Financing receivable recorded investment
Past due	1,931,000	3,134,000
Commercial, financial and agricultural | Domestic | Commercial Loan [Member] | 60 to 89 Days
Financing receivable recorded investment
Past due	1,109,000	626,000
Commercial, financial and agricultural | Domestic | Commercial Loan [Member] | 90 Days or Greater
Financing receivable recorded investment
Past due	563,000	1,292,000
Commercial, financial and agricultural | Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member]
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	186,000	54,878,000
Past due	2,840,000	65,017,000
Loans, current	2,286,468,000	1,831,730,000
Total loans	2,289,308,000	1,896,747,000
Commercial, financial and agricultural | Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] | 30 to 59 Days
Financing receivable recorded investment
Past due	2,435,000	8,058,000
Commercial, financial and agricultural | Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] | 60 to 89 Days
Financing receivable recorded investment
Past due	219,000	2,031,000
Commercial, financial and agricultural | Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] | 90 Days or Greater
Financing receivable recorded investment
Past due	186,000	54,928,000
Commercial, financial and agricultural | Domestic | Commercial Real Estate Multifamily Receivable [Member]
Financing receivable recorded investment
Past due	126,000	478,000
Loans, current	440,918,000	189,952,000
Total loans	441,044,000	190,430,000
Commercial, financial and agricultural | Domestic | Commercial Real Estate Multifamily Receivable [Member] | 30 to 59 Days
Financing receivable recorded investment
Past due	126,000	313,000
Commercial, financial and agricultural | Domestic | Commercial Real Estate Multifamily Receivable [Member] | 90 Days or Greater
Financing receivable recorded investment
Past due		165,000
Commercial Real Estate Portfolio Segment [Member]
Financing receivable recorded investment
Total loans	1,846,757,000	2,185,883,000
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development
Financing receivable recorded investment
Past due	18,500,000	564,000
Loans, current	1,828,257,000	2,185,319,000
Total loans	1,846,757,000	2,185,883,000
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development | 30 to 59 Days
Financing receivable recorded investment
Past due	1,059,000	509,000
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development | 60 to 89 Days
Financing receivable recorded investment
Past due	854,000	55,000
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development | 90 Days or Greater
Financing receivable recorded investment
Past due	16,587,000
Real estate - mortgage
Financing receivable recorded investment
Total loans	999,144,000	1,140,377,000
Real estate - mortgage | Domestic | Residential First Mortgage Financing Receivable [Member]
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	5,890,000	3,107,000
Past due	9,490,000	8,559,000
Loans, current	395,629,000	425,342,000
Total loans	405,119,000	433,901,000
Real estate - mortgage | Domestic | Residential First Mortgage Financing Receivable [Member] | 30 to 59 Days
Financing receivable recorded investment
Past due	2,399,000	3,229,000
Real estate - mortgage | Domestic | Residential First Mortgage Financing Receivable [Member] | 60 to 89 Days
Financing receivable recorded investment
Past due	926,000	1,670,000
Real estate - mortgage | Domestic | Residential First Mortgage Financing Receivable [Member] | 90 Days or Greater
Financing receivable recorded investment
Past due	6,165,000	3,660,000
Real estate - mortgage | Domestic | Residential Junior Lien
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	1,197,000	1,200,000
Past due	2,005,000	2,789,000
Loans, current	592,020,000	703,687,000
Total loans	594,025,000	706,476,000
Real estate - mortgage | Domestic | Residential Junior Lien | 30 to 59 Days
Financing receivable recorded investment
Past due	561,000	1,112,000
Real estate - mortgage | Domestic | Residential Junior Lien | 60 to 89 Days
Financing receivable recorded investment
Past due	247,000	477,000
Real estate - mortgage | Domestic | Residential Junior Lien | 90 Days or Greater
Financing receivable recorded investment
Past due	1,197,000	1,200,000
Consumer
Financing receivable recorded investment
Total loans	40,595,000	47,800,000
Consumer | Domestic
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	79,000	88,000
Past due	468,000	630,000
Loans, current	40,127,000	47,170,000
Total loans	40,595,000	47,800,000
Consumer | Domestic | 30 to 59 Days
Financing receivable recorded investment
Past due	318,000	467,000
Consumer | Domestic | 60 to 89 Days
Financing receivable recorded investment
Past due	71,000	75,000
Consumer | Domestic | 90 Days or Greater
Financing receivable recorded investment
Past due	79,000	88,000
Foreign
Financing receivable recorded investment
Total loans	138,970,000	141,049,000
Foreign | Foreign
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	568,000	11,000
Past due	1,226,000	1,361,000
Loans, current	137,744,000	139,688,000
Total loans	138,970,000	141,049,000
Foreign | Foreign | 30 to 59 Days
Financing receivable recorded investment
Past due	478,000	1,347,000
Foreign | Foreign | 60 to 89 Days
Financing receivable recorded investment
Past due	180,000	3,000
Foreign | Foreign | 90 Days or Greater
Financing receivable recorded investment
Past due	$ 568,000	$ 11,000

Allowance for Credit Losses (Po

Allowance for Credit Losses (Portfolio Credit Quality) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Loan portfolio by credit quality indicator
2020	$ 3,601,680
2019	1,627,511
2018	1,087,031
2017	556,923
2016	327,336
Prior	341,273
Total loans	7,541,754	$ 6,894,946
Pass [Member]
Loan portfolio by credit quality indicator
Total loans		6,538,085
Special Mention [Member]
Loan portfolio by credit quality indicator
Total loans		33,553
Special Pass [Member]
Loan portfolio by credit quality indicator
Total loans		62,315
Substandard [Member]
Loan portfolio by credit quality indicator
Total loans		248,318
Domestic | Commercial Loan [Member]
Loan portfolio by credit quality indicator
2020	1,288,332
2019	241,724
2018	146,051
2017	85,596
2016	14,216
Prior	10,017
Total loans	1,785,936
Domestic | Commercial Loan [Member] | Pass [Member]
Loan portfolio by credit quality indicator
2020	1,168,671
2019	240,869
2018	145,670
2017	85,434
2016	13,901
Prior	10,000
Total loans	1,664,545	1,228,110
Domestic | Commercial Loan [Member] | Special Mention [Member]
Loan portfolio by credit quality indicator
2020	75,638
Total loans	75,638	569
Domestic | Commercial Loan [Member] | Special Pass [Member]
Loan portfolio by credit quality indicator
2020	39,886
2019	11
2017	3
Prior	17
Total loans	39,917	39
Domestic | Commercial Loan [Member] | Substandard [Member]
Loan portfolio by credit quality indicator
2020	3,360
2019	683
2018	289
2016	315
Total loans	4,647	62,007
Domestic | Commercial Loan [Member] | Watch List - Doubtful
Loan portfolio by credit quality indicator
2020	777
2019	161
2018	92
2017	159
Total loans	1,189
Domestic | Commercial Real Estate: other construction and land development
Loan portfolio by credit quality indicator
2020	833,796
2019	600,602
2018	320,308
2017	78,174
2016	10,534
Prior	3,343
Total loans	1,846,757
Domestic | Commercial Real Estate: other construction and land development | Pass [Member]
Loan portfolio by credit quality indicator
2020	773,165
2019	576,707
2018	320,308
2017	78,174
2016	10,534
Prior	3,343
Total loans	1,762,231
Domestic | Commercial Real Estate: other construction and land development | Special Mention [Member]
Loan portfolio by credit quality indicator
2020	20,828
2019	21,650
Total loans	42,478
Domestic | Commercial Real Estate: other construction and land development | Special Pass [Member]
Loan portfolio by credit quality indicator
2020	23,101
2019	1,451
Total loans	24,552
Domestic | Commercial Real Estate: other construction and land development | Watch List - Doubtful
Loan portfolio by credit quality indicator
2020	16,702
2019	794
Total loans	17,496
Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member]
Loan portfolio by credit quality indicator
2020	1,002,557
2019	380,123
2018	391,303
2017	192,165
2016	206,193
Prior	116,967
Total loans	2,289,308
Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] | Pass [Member]
Loan portfolio by credit quality indicator
2020	884,070
2019	373,993
2018	386,268
2017	189,639
2016	202,500
Prior	116,729
Total loans	2,153,199	1,710,446
Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] | Special Mention [Member]
Loan portfolio by credit quality indicator
2020	3,041
2018	4,758
2017	177
2016	3,218
Total loans	11,194	13,184
Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] | Special Pass [Member]
Loan portfolio by credit quality indicator
2020	61,637
2019	942
2018	277
2017	80
Total loans	62,936	20,183
Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] | Substandard [Member]
Loan portfolio by credit quality indicator
2020	53,809
2019	4,986
2017	2,269
2016	475
Prior	1
Total loans	61,540	151,726
Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] | Watch List - Doubtful
Loan portfolio by credit quality indicator
2019	202
Prior	237
Total loans	439
Domestic | Commercial Real Estate Multifamily Receivable [Member]
Loan portfolio by credit quality indicator
2020	74,711
2019	208,356
2018	82,818
2017	64,110
2016	6,801
Prior	4,248
Total loans	441,044
Domestic | Commercial Real Estate Multifamily Receivable [Member] | Pass [Member]
Loan portfolio by credit quality indicator
2020	74,577
2019	208,356
2018	82,818
2017	64,110
2016	6,801
Prior	4,248
Total loans	440,910	190,265
Domestic | Commercial Real Estate Multifamily Receivable [Member] | Watch List - Doubtful
Loan portfolio by credit quality indicator
2020	134
Total loans	134
Domestic | Residential First Mortgage Financing Receivable [Member]
Loan portfolio by credit quality indicator
2020	81,090
2019	62,179
2018	72,430
2017	54,593
2016	29,299
Prior	105,528
Total loans	405,119
Domestic | Residential First Mortgage Financing Receivable [Member] | Pass [Member]
Loan portfolio by credit quality indicator
2020	81,004
2019	62,165
2018	72,299
2017	54,593
2016	29,250
Prior	105,463
Total loans	404,774	426,546
Domestic | Residential First Mortgage Financing Receivable [Member] | Special Mention [Member]
Loan portfolio by credit quality indicator
Total loans		253
Domestic | Residential First Mortgage Financing Receivable [Member] | Special Pass [Member]
Loan portfolio by credit quality indicator
2019	14
2018	131
Total loans	145	144
Domestic | Residential First Mortgage Financing Receivable [Member] | Substandard [Member]
Loan portfolio by credit quality indicator
2016	49
Total loans	49	680
Domestic | Residential First Mortgage Financing Receivable [Member] | Watch List - Doubtful
Loan portfolio by credit quality indicator
2020	86
Prior	65
Total loans	151
Domestic | Residential Junior Lien
Loan portfolio by credit quality indicator
2020	197,048
2019	108,276
2018	61,674
2017	75,868
2016	56,705
Prior	94,454
Total loans	594,025
Domestic | Residential Junior Lien | Pass [Member]
Loan portfolio by credit quality indicator
2020	196,308
2019	108,276
2018	61,636
2017	75,056
2016	56,705
Prior	94,454
Total loans	592,435	704,958
Domestic | Residential Junior Lien | Special Mention [Member]
Loan portfolio by credit quality indicator
2020	740
2017	812
Total loans	1,552	826
Domestic | Residential Junior Lien | Watch List - Doubtful
Loan portfolio by credit quality indicator
2018	38
Total loans	38
Commercial, financial and agricultural
Loan portfolio by credit quality indicator
Total loans	4,516,288	3,379,837
Commercial, financial and agricultural | Domestic | Commercial Loan [Member]
Loan portfolio by credit quality indicator
Total loans	1,785,936	1,292,660
Commercial, financial and agricultural | Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member]
Loan portfolio by credit quality indicator
Total loans	2,289,308	1,896,747
Commercial, financial and agricultural | Domestic | Commercial Real Estate Multifamily Receivable [Member]
Loan portfolio by credit quality indicator
Total loans	441,044	190,430
Commercial Real Estate Portfolio Segment [Member]
Loan portfolio by credit quality indicator
Total loans	1,846,757	2,185,883
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development
Loan portfolio by credit quality indicator
Total loans	1,846,757	2,185,883
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development | Pass [Member]
Loan portfolio by credit quality indicator
Total loans		2,090,370
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development | Special Mention [Member]
Loan portfolio by credit quality indicator
Total loans		18,721
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development | Special Pass [Member]
Loan portfolio by credit quality indicator
Total loans		41,949
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development | Substandard [Member]
Loan portfolio by credit quality indicator
Total loans		33,905
Real estate - mortgage
Loan portfolio by credit quality indicator
Total loans	999,144	1,140,377
Real estate - mortgage | Domestic | Residential First Mortgage Financing Receivable [Member]
Loan portfolio by credit quality indicator
Total loans	405,119	433,901
Real estate - mortgage | Domestic | Residential Junior Lien
Loan portfolio by credit quality indicator
Total loans	594,025	706,476
Consumer
Loan portfolio by credit quality indicator
Total loans	40,595	47,800
Consumer | Domestic
Loan portfolio by credit quality indicator
2020	30,910
2019	7,159
2018	875
2017	225
2016	55
Prior	1,371
Total loans	40,595	47,800
Consumer | Domestic | Pass [Member]
Loan portfolio by credit quality indicator
2020	30,910
2019	7,159
2018	875
2017	225
2016	55
Prior	1,371
Total loans	40,595	46,605
Foreign
Loan portfolio by credit quality indicator
Total loans	138,970	141,049
Foreign | Foreign
Loan portfolio by credit quality indicator
2020	93,236
2019	19,092
2018	11,572
2017	6,192
2016	3,533
Prior	5,345
Total loans	138,970	141,049
Foreign | Foreign | Pass [Member]
Loan portfolio by credit quality indicator
2020	93,236
2019	19,092
2018	11,572
2017	6,192
2016	3,533
Prior	5,345
Total loans	$ 138,970	$ 140,785

Allowance for Credit Losses (_3

Allowance for Credit Losses (Portfolio Credit Quality By Loan Class) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)item	Dec. 31, 2019USD ($)
Loan portfolio by credit quality indicator
Portfolio, total	$ 7,541,754	$ 6,894,946
Pass [Member]
Loan portfolio by credit quality indicator
Portfolio, total		6,538,085
Special Mention [Member]
Loan portfolio by credit quality indicator
Portfolio, total		33,553
Special Pass [Member]
Loan portfolio by credit quality indicator
Portfolio, total		62,315
Substandard [Member]
Loan portfolio by credit quality indicator
Portfolio, total		248,318
Nonperforming Financing Receivable [Member]
Loan portfolio by credit quality indicator
Portfolio, total		12,675
Commercial Loan [Member]
Loan portfolio by credit quality indicator
Number of additional relationships reclassified from Pass to Watch List - Pass | item	2
Number of relationships secured by oil and gas properties reclassified from pass to watch list pass | item	1
Number of relationships secured by accounts receivable and inventory that were reclassified from pass category to watch list - pass | item	1
Commercial Real Estate: other construction and land development
Loan portfolio by credit quality indicator
Number of relationships secured by real estate planned for lot development that were reclassified from Watch List pass category to special review category. | item	1
Number of relationships secured by commercial property that were reclassified from Watch List pass category to special review category. | item	1
Number of relationships secured by commercial real estate that were reclassified from Watch List pass category to special review category. | item	1
Commercial Real Estate Farmland and Commercial Receivable [Member]
Loan portfolio by credit quality indicator
Number of relationships secured by commercial real estate that were reclassified from Pass category. | item	2
Domestic | Commercial Loan [Member]
Loan portfolio by credit quality indicator
Portfolio, total	$ 1,785,936
Domestic | Commercial Loan [Member] | Pass [Member]
Loan portfolio by credit quality indicator
Portfolio, total	1,664,545	1,228,110
Domestic | Commercial Loan [Member] | Special Mention [Member]
Loan portfolio by credit quality indicator
Portfolio, total	75,638	569
Domestic | Commercial Loan [Member] | Special Pass [Member]
Loan portfolio by credit quality indicator
Portfolio, total	39,917	39
Domestic | Commercial Loan [Member] | Substandard [Member]
Loan portfolio by credit quality indicator
Portfolio, total	4,647	62,007
Domestic | Commercial Loan [Member] | Watch List - Doubtful
Loan portfolio by credit quality indicator
Portfolio, total	1,189
Domestic | Commercial Loan [Member] | Nonperforming Financing Receivable [Member]
Loan portfolio by credit quality indicator
Portfolio, total		1,935
Domestic | Commercial Real Estate: other construction and land development
Loan portfolio by credit quality indicator
Portfolio, total	1,846,757
Domestic | Commercial Real Estate: other construction and land development | Pass [Member]
Loan portfolio by credit quality indicator
Portfolio, total	1,762,231
Domestic | Commercial Real Estate: other construction and land development | Special Mention [Member]
Loan portfolio by credit quality indicator
Portfolio, total	42,478
Domestic | Commercial Real Estate: other construction and land development | Special Pass [Member]
Loan portfolio by credit quality indicator
Portfolio, total	24,552
Domestic | Commercial Real Estate: other construction and land development | Watch List - Doubtful
Loan portfolio by credit quality indicator
Portfolio, total	17,496
Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member]
Loan portfolio by credit quality indicator
Portfolio, total	2,289,308
Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] | Pass [Member]
Loan portfolio by credit quality indicator
Portfolio, total	2,153,199	1,710,446
Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] | Special Mention [Member]
Loan portfolio by credit quality indicator
Portfolio, total	11,194	13,184
Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] | Special Pass [Member]
Loan portfolio by credit quality indicator
Portfolio, total	62,936	20,183
Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] | Substandard [Member]
Loan portfolio by credit quality indicator
Portfolio, total	61,540	151,726
Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] | Watch List - Doubtful
Loan portfolio by credit quality indicator
Portfolio, total	439
Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member] | Nonperforming Financing Receivable [Member]
Loan portfolio by credit quality indicator
Portfolio, total		1,208
Domestic | Commercial Real Estate Multifamily Receivable [Member]
Loan portfolio by credit quality indicator
Portfolio, total	441,044
Domestic | Commercial Real Estate Multifamily Receivable [Member] | Pass [Member]
Loan portfolio by credit quality indicator
Portfolio, total	440,910	190,265
Domestic | Commercial Real Estate Multifamily Receivable [Member] | Watch List - Doubtful
Loan portfolio by credit quality indicator
Portfolio, total	134
Domestic | Commercial Real Estate Multifamily Receivable [Member] | Nonperforming Financing Receivable [Member]
Loan portfolio by credit quality indicator
Portfolio, total		165
Domestic | Residential First Mortgage Financing Receivable [Member]
Loan portfolio by credit quality indicator
Portfolio, total	405,119
Domestic | Residential First Mortgage Financing Receivable [Member] | Pass [Member]
Loan portfolio by credit quality indicator
Portfolio, total	404,774	426,546
Domestic | Residential First Mortgage Financing Receivable [Member] | Special Mention [Member]
Loan portfolio by credit quality indicator
Portfolio, total		253
Domestic | Residential First Mortgage Financing Receivable [Member] | Special Pass [Member]
Loan portfolio by credit quality indicator
Portfolio, total	145	144
Domestic | Residential First Mortgage Financing Receivable [Member] | Substandard [Member]
Loan portfolio by credit quality indicator
Portfolio, total	49	680
Domestic | Residential First Mortgage Financing Receivable [Member] | Watch List - Doubtful
Loan portfolio by credit quality indicator
Portfolio, total	151
Domestic | Residential First Mortgage Financing Receivable [Member] | Nonperforming Financing Receivable [Member]
Loan portfolio by credit quality indicator
Portfolio, total		6,278
Domestic | Residential Junior Lien
Loan portfolio by credit quality indicator
Portfolio, total	594,025
Domestic | Residential Junior Lien | Pass [Member]
Loan portfolio by credit quality indicator
Portfolio, total	592,435	704,958
Domestic | Residential Junior Lien | Special Mention [Member]
Loan portfolio by credit quality indicator
Portfolio, total	1,552	826
Domestic | Residential Junior Lien | Watch List - Doubtful
Loan portfolio by credit quality indicator
Portfolio, total	38
Domestic | Residential Junior Lien | Nonperforming Financing Receivable [Member]
Loan portfolio by credit quality indicator
Portfolio, total		692
Commercial, financial and agricultural
Loan portfolio by credit quality indicator
Portfolio, total	4,516,288	3,379,837
Commercial, financial and agricultural | Domestic | Commercial Loan [Member]
Loan portfolio by credit quality indicator
Portfolio, total	1,785,936	1,292,660
Commercial, financial and agricultural | Domestic | Commercial Real Estate Farmland and Commercial Receivable [Member]
Loan portfolio by credit quality indicator
Portfolio, total	2,289,308	1,896,747
Commercial, financial and agricultural | Domestic | Commercial Real Estate Multifamily Receivable [Member]
Loan portfolio by credit quality indicator
Portfolio, total	441,044	190,430
Commercial Real Estate Portfolio Segment [Member]
Loan portfolio by credit quality indicator
Portfolio, total	1,846,757	2,185,883
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development
Loan portfolio by credit quality indicator
Portfolio, total	1,846,757	2,185,883
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development | Pass [Member]
Loan portfolio by credit quality indicator
Portfolio, total		2,090,370
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development | Special Mention [Member]
Loan portfolio by credit quality indicator
Portfolio, total		18,721
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development | Special Pass [Member]
Loan portfolio by credit quality indicator
Portfolio, total		41,949
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development | Substandard [Member]
Loan portfolio by credit quality indicator
Portfolio, total		33,905
Commercial Real Estate Portfolio Segment [Member] | Domestic | Commercial Real Estate: other construction and land development | Nonperforming Financing Receivable [Member]
Loan portfolio by credit quality indicator
Portfolio, total		938
Real estate - mortgage
Loan portfolio by credit quality indicator
Portfolio, total	999,144	1,140,377
Real estate - mortgage | Domestic | Residential First Mortgage Financing Receivable [Member]
Loan portfolio by credit quality indicator
Portfolio, total	405,119	433,901
Real estate - mortgage | Domestic | Residential Junior Lien
Loan portfolio by credit quality indicator
Portfolio, total	594,025	706,476
Consumer
Loan portfolio by credit quality indicator
Portfolio, total	40,595	47,800
Consumer | Domestic
Loan portfolio by credit quality indicator
Portfolio, total	40,595	47,800
Consumer | Domestic | Pass [Member]
Loan portfolio by credit quality indicator
Portfolio, total	40,595	46,605
Consumer | Domestic | Nonperforming Financing Receivable [Member]
Loan portfolio by credit quality indicator
Portfolio, total		1,195
Foreign
Loan portfolio by credit quality indicator
Portfolio, total	138,970	141,049
Foreign | Foreign
Loan portfolio by credit quality indicator
Portfolio, total	138,970	141,049
Foreign | Foreign | Pass [Member]
Loan portfolio by credit quality indicator
Portfolio, total	$ 138,970	140,785
Foreign | Foreign | Nonperforming Financing Receivable [Member]
Loan portfolio by credit quality indicator
Portfolio, total		$ 264

Bank Premises and Equipment (De

Bank Premises and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Bank premises and equipment
Less: accumulated depreciation	$ (526,939)	$ (498,641)
Bank premises and equipment, net	479,878	506,595
Building and Building Improvements [Member]
Bank premises and equipment
Bank premises and equipment, gross	$ 577,656	573,257
Building and Building Improvements [Member] | Minimum [Member]
Bank premises and equipment
Estimated useful lives	5 years
Building and Building Improvements [Member] | Maximum [Member]
Bank premises and equipment
Estimated useful lives	39 years
Furniture Equipment and Vehicles [Member]
Bank premises and equipment
Bank premises and equipment, gross	$ 311,313	313,880
Furniture Equipment and Vehicles [Member] | Minimum [Member]
Bank premises and equipment
Estimated useful lives	1 year
Furniture Equipment and Vehicles [Member] | Maximum [Member]
Bank premises and equipment
Estimated useful lives	20 years
Land [Member]
Bank premises and equipment
Bank premises and equipment, gross	$ 117,848	$ 118,099

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Identified intangible assets
Carrying Amount	$ 60,697,000	$ 60,697,000
Accumulated Amortization	60,697,000	60,697,000
Amortization expense	0	0	$ 0
Estimated amortization expense for each of the five succeeding fiscal years and thereafter
Changes in carrying amount of goodwill	0	0
Core Deposits [Member]
Identified intangible assets
Carrying Amount	58,675,000	58,675,000
Accumulated Amortization	58,675,000	58,675,000
Contractual Rights [Member]
Identified intangible assets
Carrying Amount	2,022,000	2,022,000
Accumulated Amortization	$ 2,022,000	$ 2,022,000

Deposits (Details)

Deposits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Demand non-interest bearing
Domestic	$ 3,781,277	$ 2,815,835
Foreign	934,537	730,070
Total demand non-interest bearing	4,715,814	3,545,905
Savings and interest bearing demand
Domestic	2,919,314	2,477,668
Foreign	933,191	790,161
Total savings and interest bearing demand	3,852,505	3,267,829
$100,000 or more
Time, certificate of deposit	1,621,084
Less than $100,000
Domestic	291,473	302,620
Foreign	241,989	246,644
Total time, certificates of deposit	2,153,541	2,012,300
Total deposits	10,721,860	8,826,034
Savings and interest bearing demand
Domestic	5,098	13,462	$ 11,029
Foreign	1,260	2,917	1,735
Total savings and interest bearing demand	6,358	16,379	12,764
$100,000 or more
Domestic	8,827	7,804	4,741
Foreign	7,536	9,407	5,798
Less than $100,000
Domestic	1,781	2,232	1,589
Foreign	1,086	1,527	968
Total time, certificates of deposit	19,230	20,970	13,096
Total interest expense on deposits	25,588	37,349	$ 25,860
Domestic
$100,000 or more
Time, certificate of deposit	797,692	636,005
Foreign
$100,000 or more
Time, certificate of deposit	$ 822,387	$ 827,031

Deposits (Scheduled Maturities)

Deposits (Scheduled Maturities) (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Scheduled maturities of time deposits
2021	$ 1,971,433,000
2022	141,388,000
2023	28,781,000
2024	11,205,000
2025	681,000
Thereafter	53,000
Total time, certificates of deposit	2,153,541,000	$ 2,012,300,000
Time Deposits 250,000 or exceed	250,000	$ 1,085,404,000	$ 929,860
Scheduled maturities of time deposits in amounts of $100,000 or more
Due within 3 months or less	606,807,000
Due after 3 months and within 6 months	385,859,000
Due after 6 months and within 12 months	498,626,000
Due after 12 months	129,792,000
Total	$ 1,621,084,000

Securities Sold Under Repurch_3

Securities Sold Under Repurchase Agreements (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Collateral Securities and Repurchase Borrowing agreements
Average outstanding amount	$ 335,392,000	$ 267,439,000
Maximum amount outstanding at any month end	428,148,000	299,827,000
Collateralized Securities, Book Value of Securities Sold	517,704,000	328,671,000
Collateralized securities, Fair Value of Securities Sold	518,805,000	329,926,000
Repurchase Borrowing, Balance of Liability	$ 428,148,000	$ 236,536,000
Repurchase Borrowing, Weighted Average Interest Rate (as a percent)	0.14%	0.89%
Maturity Overnight [Member]
Collateral Securities and Repurchase Borrowing agreements
Collateralized Securities, Book Value of Securities Sold	$ 506,020,000	$ 317,107,000
Collateralized securities, Fair Value of Securities Sold	507,164,000	318,397,000
Repurchase Borrowing, Balance of Liability	$ 416,757,000	$ 225,243,000
Repurchase Borrowing, Weighted Average Interest Rate (as a percent)	0.13%	0.87%
Maturity over 90 days [Member]
Collateral Securities and Repurchase Borrowing agreements
Collateralized Securities, Book Value of Securities Sold	$ 11,684,000	$ 11,564,000
Collateralized securities, Fair Value of Securities Sold	11,641,000	11,529,000
Repurchase Borrowing, Balance of Liability	$ 11,391,000	$ 11,293,000
Repurchase Borrowing, Weighted Average Interest Rate (as a percent)	0.43%	1.28%

Other Borrowed Funds (Details)

Other Borrowed Funds (Details)	12 Months Ended
	Dec. 31, 2020USD ($)loan	Dec. 31, 2019USD ($)
Federal Home Loan Bank advances
Other borrowed funds	$ 436,327,000	$ 626,511,000
Short-term Debt [Member]
Federal Home Loan Bank advances
Other borrowed funds		$ 190,000,000
Rate on balance outstanding at year end (as a percent)		1.48%
Average daily balance	$ 110,776,000	$ 190,431,000
Average rate (as a percent)	1.19%	2.60%
Maximum amount outstanding at any month end	$ 292,000,000	$ 371,775,000
Long-term Debt [Member]
Federal Home Loan Bank advances
Other borrowed funds	$ 436,327,000	$ 436,511,000
Rate on balance outstanding at year end (as a percent)	1.73%	1.73%
Average daily balance	$ 436,411,000	$ 436,593,000
Average rate (as a percent)	1.71%	1.71%
Maximum amount outstanding at any month end	$ 436,495,000	$ 436,675,000
Long-term Debt [Member] | Federal Home Loan Bank advances maturing July 2028
Federal Home Loan Bank advances
Other borrowed funds	75,000,000
Long-term Debt [Member] | Federal Home Loan Bank advances maturing March 2033
Federal Home Loan Bank advances
Other borrowed funds	100,000,000
Long-term Debt [Member] | Federal Home Loan Bank advances maturing August 2033
Federal Home Loan Bank advances
Other borrowed funds	$ 250,000,000
Long-term Debt [Member] | Federal Home Loan Bank amortizing advances
Federal Home Loan Bank advances
Number of amortizing advances | loan	2
Amortizing in 2021	$ 189,000
Amortizing in 2022	194,000
Amortizing in 2023	199,000
Amortizing in 2024	204,000
Amortizing in 2025	210,000
Long-term Debt [Member] | Federal Home Loan Bank advances maturing December 2033
Federal Home Loan Bank advances
Other borrowed funds	3,091,000
Long-term Debt [Member] | Federal Home Loan Bank advances maturing November 2033
Federal Home Loan Bank advances
Other borrowed funds	$ 8,236,000

Junior Subordinated Deferrabl_3

Junior Subordinated Deferrable Interest Debentures (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)item	Dec. 31, 2019USD ($)
Junior subordinated interest deferrable debentures, major types of business trusts
Number of statutory business trusts issuing trust preferred securities | item	5
Junior subordinated deferrable interest debentures	$ 134,642	$ 134,642
Maximum number of consecutive quarterly period available for deferral of interest payment on Trusts VIII, IX, X, XI and XII | item	20
Percentage of capital securities issued by trust qualifying as Tier I capital, maximum	25.00%
Percentage of capital securities issued by trust qualifying as Tier II capital, minimum	25.00%
Capital securities issued by the trust, qualifying as Tier I capital	$ 134,642
Trust XI
Junior subordinated interest deferrable debentures, major types of business trusts
Junior subordinated deferrable interest debentures	25,990
Trust X
Junior subordinated interest deferrable debentures, major types of business trusts
Junior subordinated deferrable interest debentures	$ 21,021

Junior Subordinated Deferrabl_4

Junior Subordinated Deferrable Interest Debentures (Key Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Junior subordinated interest deferrable debentures, major types of business trusts
Junior subordinated deferrable interest debentures	$ 134,642	$ 134,642
Trust VIII
Junior subordinated interest deferrable debentures, major types of business trusts
Junior subordinated deferrable interest debentures	$ 25,774
Interest rate (as a percent)	3.29%
Interest rate index	LIBOR
Spread on interest rate index (as a percent)	3.05%
Trust IX
Junior subordinated interest deferrable debentures, major types of business trusts
Junior subordinated deferrable interest debentures	$ 41,238
Interest rate (as a percent)	1.85%
Interest rate index	LIBOR
Spread on interest rate index (as a percent)	1.62%
Trust X
Junior subordinated interest deferrable debentures, major types of business trusts
Junior subordinated deferrable interest debentures	$ 21,021
Interest rate (as a percent)	1.86%
Interest rate index	LIBOR
Spread on interest rate index (as a percent)	1.65%
Trust XI
Junior subordinated interest deferrable debentures, major types of business trusts
Junior subordinated deferrable interest debentures	$ 25,990
Interest rate (as a percent)	1.85%
Interest rate index	LIBOR
Spread on interest rate index (as a percent)	1.62%
Trust XII
Junior subordinated interest deferrable debentures, major types of business trusts
Junior subordinated deferrable interest debentures	$ 20,619
Interest rate (as a percent)	1.68%
Interest rate index	LIBOR
Spread on interest rate index (as a percent)	1.45%

Earnings per Share ("EPS") (Det

Earnings per Share ("EPS") (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Basic EPS
Net income	$ 167,319	$ 205,104	$ 215,931
Shares (Denominator)	63,725,819	65,476,606	66,106,580
Per Share Amount	$ 2.63	$ 3.13	$ 3.27
Diluted EPS
Net Income	$ 167,319	$ 205,104	$ 215,931
Potential dilutive common shares and warrants	127,316	209,078	527,240
Shares (Denominator)	63,853,135	65,685,684	66,633,820
Per Share Amount (in dollars per share)	$ 2.62	$ 3.12	$ 3.24

Employees' Profit Sharing Plan

Employees' Profit Sharing Plan (Details) - Deferred Profit Sharing [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employees' profit sharing plan
Minimum period of continuous employment to be fully vested	1 year
Profit sharing costs	$ 4,000	$ 4,200	$ 3,850

International Operations (Detai

International Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Loans
Loans	$ 7,541,754	$ 6,894,946
Less allowance for credit losses	(109,059)	(60,278)	$ (61,384)	$ (67,687)
Net loans	7,432,695	6,834,668
Accrued interest receivable	37,881	36,620
International Banking Services [Member]
Loans
Accrued interest receivable	605	743
Outstanding standby and commercial letters of credit	118,722
Revenues	4,676	5,445	$ 5,412
International Banking Services [Member] | Foreign
Loans
Loans	138,970	141,049
Less allowance for credit losses	(753)	(823)
Net loans	138,217	140,226
International Banking Services [Member] | Foreign | Commercial
Loans
Loans	90,177	88,979
International Banking Services [Member] | Foreign | Others
Loans
Loans	$ 48,793	$ 52,070

Income Taxes (Current and Defer

Income Taxes (Current and Deferred Portions of Net Income Tax Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current
U.S.	$ 43,794	$ 48,559	$ 48,144
State	3,709	2,944	3,370
Foreign	58	38	(5)
Total current taxes	47,561	51,541	51,509
Deferred
U.S.	(2,733)	2,979	5,130
State	(389)	330	13
Total deferred taxes	(3,122)	3,309	5,143
Total income taxes	$ 44,439	$ 54,850	$ 56,652

Income Taxes (Income Tax Expens

Income Taxes (Income Tax Expense Differences from the Amount Computed by Applying the U.S. Federal Income Tax Rate) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
U.S. Federal income tax rate (as a percent)	21.00%	21.00%	21.00%
Reasons for the difference of income tax expense
Computed expected tax expense	$ 45,218	$ 55,086	$ 57,831
Change in taxes resulting from:
Tax-exempt interest income	(2,709)	(2,550)	(3,101)
State tax, net of federal income taxes and tax credit and refunds	2,622	2,587	2,673
Other investment income	(2,205)	(1,480)	(1,561)
Deferred tax adjustment due to federal tax rate change			(1,618)
Net investment expense, low income housing investment	1,990	623	2,518
Other	(477)	584	(90)
Total income taxes	$ 44,439	$ 54,850	$ 56,652

Income Taxes (Deferred Tax Asse

Income Taxes (Deferred Tax Assets and Deferred Tax Liabilities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Loans receivable, principally due to the allowance for probable loan losses	$ 21,921	$ 12,050
Other real estate owned	1,183	2,501
Impairment charges on available-for-sale securities		1,054
Accrued expenses	81	98
Other	5,649	6,019
Total deferred tax assets	28,834	21,722
Deferred tax liabilities:
Bank premises and equipment, principally due to differences on depreciation	(12,350)	(12,478)
Net unrealized gains on available for sale investment securities	(5,679)	(508)
Impairment charges on available-for-securities	(19)
Identified intangible assets and goodwill	(13,807)	(13,649)
Other	(20,551)	(18,849)
Total deferred tax liabilities	52,406	45,484
Net deferred tax liability	$ (23,572)	$ (23,762)
U.S. Federal income tax rate (as a percent)	21.00%	21.00%	21.00%

Stock Options (Details)

Stock Options (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Apr. 05, 2012
Employee Stock Option [Member]
Stock option details
Shares available for future grants	10,102			800,000
Maximum exercisable period for options granted	10 years
Black-Scholes-Merton option valuation model assumptions
Expected Life (Years)	7 years	7 years
Dividend yield (as a percent)	6.04%	2.93%
Interest rate (as a percent)	0.74%	1.97%
Volatility (as a percent)	29.04%	26.97%
Number of options granted (in shares)	35,000
Stock option activity
Options outstanding at the beginning of the period (in shares)	658,588
Plus: Options granted (in shares)	35,000
Less:
Exercise of stock options (in shares)	26,010
Options forfeited (in shares)	16,451
Options outstanding at the end of the period (in shares)	651,127	658,588
Options fully vested and exercisable at the end of the period (in shares)	409,782
Stock Options, Weighted average exercise price
Options outstanding at the beginning, weighted average exercise price (in dollars per share)	$ 27.55
Plus: Options granted, weighted average exercise price (in dollars per share)	18.79
Less:
Options exercised, weighted average exercise price (in dollars per share)	20.87
Options forfeited, weighted average exercise price (in dollars per share)	31.94
Options outstanding at the end, weighted average exercise price (in dollars per share)	27.24	$ 27.55
Options fully vested and exercisable at the end, weighted average exercise price (in dollars per share)	$ 22.98
Stock Options, Weighted average remaining contractual term (years)
Options outstanding at the end, weighted average remaining contractual term (years)	5 years 18 days
Options fully vested and exercisable at the end, weighted average remaining contractual term (years)	3 years 7 months 9 days
Stock Options, Aggregate intrinsic value
Options outstanding at the end, aggregate intrinsic value	$ 6,817,000
Options fully vested and exercisable at the end, aggregate intrinsic value	5,953,000
Stock-based compensation expense	743,000	$ 980,000	$ 1,035,000
Stock-based compensation cost, unrecognized, related to non-vested options	$ 1,254,000
Stock-based compensation cost, unrecognized, related to non-vested options, weighted-average period of recognition	1 year 8 months 12 days
Other information pertaining to option activity
Weighted average grant date fair value of stock options granted (in dollars per share)	$ 2.46	$ 7.38	$ 11.78
Total fair value of stock options vested	$ 1,218,000	$ 1,333,000	$ 1,077,000
Total intrinsic value of stock options exercised	$ 356,000	$ 2,373,000	$ 2,045,000
Incentive Stock Options to 10 Percent Shareholders [Member]
Stock option details
Maximum exercisable period for options granted	5 years

Long Term Restricted Stock Un_2

Long Term Restricted Stock Units (Details) - International Bancshares Corporation, Long Term Restricted Stock Unit Plan 2009 [Member] - Restricted Stock Units (RSUs) [Member]	12 Months Ended
	Dec. 31, 2020shares
Long-Term Restricted Stock Units
Granted units	0
Outstanding grants (in shares)	0

Commitments, Contingent Liabi_2

Commitments, Contingent Liabilities and Other Tax Matters (Details)	Dec. 31, 2019USD ($)
Commitments and Contingent Liabilities and Other Matters, details
Approximate cash maintained to satisfy regulatory reserve requirements	$ 125,764,000

Transactions with Related Par_2

Transactions with Related Parties (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Aggregate amount receivable from related parties	$ 30,398,000	$ 37,605,000

Financial Instruments with Of_3

Financial Instruments with Off-Statement of Condition Risk and Concentrations of Credit Risk (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Maximum [Member]
Financial amounts of instruments, whose contract amounts represent credit risks
Credit risk commitment, maximum expiration date	1 year
Commitments to Extend Credit [Member]
Financial amounts of instruments, whose contract amounts represent credit risks
Outstanding amount of financial instruments whose, contract amounts represent credit risks	$ 2,354,010,000
Line of Credit [Member]
Financial amounts of instruments, whose contract amounts represent credit risks
Outstanding amount of financial instruments whose, contract amounts represent credit risks	13,579,000
Standby Letters of Credit [Member]
Financial amounts of instruments, whose contract amounts represent credit risks
Outstanding amount of financial instruments whose, contract amounts represent credit risks	118,381,000
Guarantee obligations, maximum exposure	118,381,000
Commercial Letters of Credit [Member]
Financial amounts of instruments, whose contract amounts represent credit risks
Outstanding amount of financial instruments whose, contract amounts represent credit risks	341,000
Unsecured Letters of Credit [Member]
Financial amounts of instruments, whose contract amounts represent credit risks
Unsecured letters of credit	$ 39,487,000	$ 49,965,000

Capital Requirements (Details)

Capital Requirements (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2018
Payments for repurchase of warrants		$ 29,005,000
Dividend payable by subsidiaries, maximum	$ 948,000,000

Capital Requirements (Capital A

Capital Requirements (Capital Amounts and Ratios) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Capital Requirements
Percentage of capital securities issued by trust qualifying as Tier I capital, maximum	25.00%
Percentage of capital securities issued by trust qualifying as Tier II capital, minimum	25.00%
Capital securities issued by the trust, qualifying as Tier I capital	$ 134,642
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust	134,642	$ 134,642
Parent Company [Member]
Capital Requirements
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount	$ 1,874,641	$ 1,833,174
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent)	19.05%	18.58%
Total Capital (to Risk Weighted Assets), Actual Amount	$ 2,105,360	$ 2,018,488
Tier 1 Capital (to Risk Weighted Assets), Actual Amount	1,992,403	1,953,711
Tier 1 Capital (to Average Assets), Actual Amount	$ 1,992,403	$ 1,953,711
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent)	21.40	20.46
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent)	20.25	19.80
Tier 1 capital (to Average Assets), Actual Ratio (as a percent)	14.92	16.65
Parent Company [Member] | Minimum [Member]
Capital Requirements
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount	$ 688,678	$ 690,746
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent)	7.00%	7.00%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount	$ 1,033,017	$ 1,036,118
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount	836,252	838,762
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount	$ 534,228	$ 469,267
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent)	10.500	10.500
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent)	8.500	8.500
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent)	4	4
International Bank of Commerce Laredo [Member]
Capital Requirements
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount	$ 1,295,437	$ 1,268,078
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent)	18.19%	18.23%
Total Capital (to Risk Weighted Assets), Actual Amount	$ 1,380,685	$ 1,315,453
Tier 1 Capital (to Risk Weighted Assets), Actual Amount	1,295,437	1,268,078
Tier 1 Capital (to Average Assets), Actual Amount	$ 1,295,437	$ 1,268,078
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent)	19.39	18.91
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent)	18.19	18.23
Tier 1 capital (to Average Assets), Actual Ratio (as a percent)	13.11	15.21
International Bank of Commerce Laredo [Member] | Minimum [Member]
Capital Requirements
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount	$ 498,492	$ 486,950
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 462,885	$ 452,168
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent)	7.00%	7.00%
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	6.50%	6.50%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount	$ 747,737	$ 730,425
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	712,131	695,643
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount	605,311	591,296
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	569,705	556,514
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount	395,289	333,576
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 494,112	$ 416,970
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent)	10.500	10.500
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	10	10
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent)	8.500	8.500
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	8	8
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent)	4	4
Tier 1 Capital (to Average Assets), To Be well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	5	5
International Bank Of Commerce Oklahoma
Capital Requirements
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount	$ 207,339	$ 201,202
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent)	17.45%	16.91%
Total Capital (to Risk Weighted Assets), Actual Amount	$ 218,657	$ 206,807
Tier 1 Capital (to Risk Weighted Assets), Actual Amount	207,339	201,202
Tier 1 Capital (to Average Assets), Actual Amount	$ 207,339	$ 201,202
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent)	18.41	17.38
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent)	17.45	16.91
Tier 1 capital (to Average Assets), Actual Ratio (as a percent)	12.98	14.79
International Bank Of Commerce Oklahoma | Minimum [Member]
Capital Requirements
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount	$ 83,150	$ 83,303
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 77,211	$ 77,353
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent)	7.00%	7.00%
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	6.50%	6.50%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount	$ 124,725	$ 124,955
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	118,786	119,004
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount	100,968	101,154
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	95,029	95,203
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount	63,879	54,406
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 79,848	$ 68,007
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent)	10.500	10.500
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	10	10
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent)	8.500	8.500
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	8	8
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent)	4	4
Tier 1 Capital (to Average Assets), To Be well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	5	5
International Bank of Commerce Brownsville [Member]
Capital Requirements
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount	$ 189,575	$ 185,112
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent)	22.18%	22.70%
Total Capital (to Risk Weighted Assets), Actual Amount	$ 200,269	$ 192,417
Tier 1 Capital (to Risk Weighted Assets), Actual Amount	189,575	185,112
Tier 1 Capital (to Average Assets), Actual Amount	$ 189,575	$ 185,112
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent)	23.43	23.60
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent)	22.18	22.70
Tier 1 capital (to Average Assets), Actual Ratio (as a percent)	14.55	17.41
International Bank of Commerce Brownsville [Member] | Minimum [Member]
Capital Requirements
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount	$ 59,843	$ 57,084
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 55,569	$ 53,006
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent)	7.00%	7.00%
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	6.50%	6.50%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount	$ 89,765	$ 85,626
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	85,490	81,548
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount	72,667	69,316
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	68,392	65,239
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount	52,101	42,529
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 65,127	$ 53,161
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent)	10.500	10.500
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	10	10
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent)	8.500	8.500
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	8	8
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent)	4	4
Tier 1 Capital (to Average Assets), To Be well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	5	5
International Bank of Commerce Zapata [Member]
Capital Requirements
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount	$ 71,369	$ 72,402
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent)	34.51%	36.46%
Total Capital (to Risk Weighted Assets), Actual Amount	$ 73,510	$ 74,737
Tier 1 Capital (to Risk Weighted Assets), Actual Amount	71,369	72,402
Tier 1 Capital (to Average Assets), Actual Amount	$ 71,369	$ 72,402
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent)	35.55	37.63
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent)	34.51	36.46
Tier 1 capital (to Average Assets), Actual Ratio (as a percent)	16.52	19.08
International Bank of Commerce Zapata [Member] | Minimum [Member]
Capital Requirements
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount	$ 14,476	$ 13,902
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 13,442	$ 12,909
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent)	7.00%	7.00%
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	6.50%	6.50%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount	$ 21,714	$ 20,853
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	20,680	19,860
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount	17,578	16,881
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	16,544	15,888
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount	17,277	15,179
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 21,596	$ 18,974
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent)	10.500	10.500
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	10	10
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent)	8.500	8.500
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	8	8
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent)	4	4
Tier 1 Capital (to Average Assets), To Be well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	5	5
Commerce Bank [Member]
Capital Requirements
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount	$ 93,426	$ 91,239
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio (as a percent)	35.64%	34.83%
Total Capital (to Risk Weighted Assets), Actual Amount	$ 96,240
Tier 1 Capital (to Risk Weighted Assets), Actual Amount	93,426	$ 93,396
Tier 1 Capital (to Average Assets), Actual Amount	$ 93,426	$ 91,239
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent)	36.72	35.65
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent)	35.64	34.83
Tier 1 capital (to Average Assets), Actual Ratio (as a percent)	16.69	18.18
Commerce Bank [Member] | Minimum [Member]
Capital Requirements
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount	$ 18,347	$ 18,336
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 17,037	$ 17,026
Common Equity Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent)	7.00%	7.00%
Common Equity Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	6.50%	6.50%
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount	$ 27,521	$ 27,504
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	26,210	26,195
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Amount	22,279	22,265
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	20,968	20,956
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Amount	22,394	20,073
Tier 1 Capital (to Average Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 27,993	$ 25,091
Total Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent)	10.500	10.500
Total Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	10	10
Tier 1 Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Ratio (as a percent)	8.500	8.500
Tier 1 Capital (to Risk Weighted Assets), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	8	8
Tier 1 Capital (to Average Assets), For Capital Adequacy Purposes Ratio (as a percent)	4	4
Tier 1 Capital (to Average Assets), To Be well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	5	5

Fair Value (Fair Value By Level

Fair Value (Fair Value By Level) (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Assets:
Available for sale debt securities	$ 3,080,768,000	$ 3,378,923,000
Equity Securities	6,202,000	6,095,000
Marketable Securities	3,090,370,000	3,387,418,000
Estimate of Fair Value Measurement [Member] | Collateralized Mortgage Backed Securities [Member]
Assets:
Available for sale debt securities	3,029,954,000	3,285,548,000
Estimate of Fair Value Measurement [Member] | US States and Political Subdivisions Debt Securities [Member]
Assets:
Available for sale debt securities	50,814,000	93,375,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets:
Equity Securities	6,202,000	6,095,000
Marketable Securities	6,202,000	6,095,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets:
Marketable Securities	3,080,768,000	3,378,923,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Collateralized Mortgage Backed Securities [Member]
Assets:
Available for sale debt securities	3,029,954,000	3,285,548,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member]
Assets:
Available for sale debt securities	50,814,000	93,375,000
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member]
Assets:
Equity Securities	6,202,000	6,095,000
Marketable Securities	3,086,970,000	3,385,018,000
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Collateralized Mortgage Backed Securities [Member]
Assets:
Available for sale debt securities	3,029,954,000	3,285,548,000
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member] | US States and Political Subdivisions Debt Securities [Member]
Assets:
Available for sale debt securities	$ 50,814,000	$ 93,375,000

Fair Value (Fair Value Measurem

Fair Value (Fair Value Measurement and Assumptions) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets:
Impaired Loans	$ 18,361,000	$ 2,955,000
Non-financial assets:
Other real estate owned	60,487,300	71,103,000
Assumptions used in discounted cash flow model to determine fair value of investments classified within level 3
Charges to allowance for probable loan losses in connection with other real estate owned	22,000	9,611,000	$ 170,000
Adjustment to fair value in connection with other real estate owned	1,539,000	322,000	$ 3,071,000
Impaired commercial collateral dependent receivables appraisals to determine fair value within immediately preceding twelve months	16,587,000	1,426,000
Impaired collateral dependent commercial loans with internal evaluation completed within last twelve months	1,283,000	847,000
Fair Value, Measurements, Nonrecurring [Member]
Assets:
Equity investments without a readily determinable fair value		28,166,000
Assumptions used in discounted cash flow model to determine fair value of investments classified within level 3
Change in net provision, impaired loans	(86,000)	43,000
Change in net provision, other real estate owned	1,539,000	322,000
Change in net provision, equity investment without readily determinable fair value		4,775,000
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets:
Impaired Loans	393,000	826,000
Equity investments without a readily determinable fair value		28,166,000
Non-financial assets:
Other real estate owned	6,241,000	21,614,000
Fair Value, Measurements, Nonrecurring [Member] | Estimate of Fair Value Measurement [Member]
Assets:
Impaired Loans	393,000	826,000
Non-financial assets:
Other real estate owned	$ 6,241,000	$ 21,614,000

Fair Value (Other Assumptions)

Fair Value (Other Assumptions) (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Deposits
Carrying amount of time deposits	$ 2,153,541,000	$ 2,012,300,000
Fair Value, Inputs, Level 3 [Member]
Loans
Carrying amount of fixed rate performing loans	1,812,413,000	1,503,811,000
Estimated fair value of fixed rate performing loans	1,747,257,000	1,481,239,000
Deposits
Carrying amount of time deposits	2,153,541,000	2,012,300,000
Estimated fair value of time deposits	2,148,976,000	2,011,950,000
Fair Value, Inputs, Level 2 [Member]
Other borrowed funds
Carrying amount of the long-term FHLB borrowings	436,372,000	436,511,000
Estimated fair value of long-term FHLB borrowings	$ 480,475,000	$ 465,017,000

International Bancshares Corp_7

International Bancshares Corporation (Parent Company Only) Financial Information Statements of Condition (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
ASSETS
Other investments	$ 254,413	$ 318,427
Notes loans	7,432,695	6,834,668
Goodwill	282,532	282,532
Other assets	162,079	200,121
Total assets	14,029,467	12,112,894
Liabilities:
Junior subordinated deferrable interest debentures	134,642	134,642
Other liabilities	130,492	171,118
Total liabilities	11,851,469	9,994,841
Shareholders' equity:
Common shares	96,241	96,215
Surplus	149,334	148,075
Retained earnings	2,289,626	2,200,568
Accumulated other comprehensive income (loss)	20,825	2,345
Total shareholders' equity before treasury stock	2,556,026	2,447,203
Less cost of shares in treasury	(378,028)	(329,150)
Total shareholders' equity	2,177,998	2,118,053	$ 1,939,582	$ 1,838,980
Total liabilities and shareholders' equity	14,029,467	12,112,894
Parent Company [Member] | Reportable Legal Entities
ASSETS
Cash	66,252	24,290
Other investments	77,661	106,284
Notes loans	11,950	12,100
Investment in subsidiaries	2,167,516	2,120,391
Goodwill	3,365	3,365
Other assets		264
Total assets	2,326,744	2,266,694
Liabilities:
Junior subordinated deferrable interest debentures	134,642	134,642
Due to IBC Trading	21	21
Other liabilities	14,083	13,978
Total liabilities	148,746	148,641
Shareholders' equity:
Common shares	96,241	96,215
Surplus	149,334	148,075
Retained earnings	2,289,626	2,200,568
Accumulated other comprehensive income (loss)	20,825	2,345
Total shareholders' equity before treasury stock	2,556,026	2,447,203
Less cost of shares in treasury	(378,028)	(329,150)
Total shareholders' equity	2,177,998	2,118,053
Total liabilities and shareholders' equity	$ 2,326,744	$ 2,266,694

International Bancshares Corp_8

International Bancshares Corporation (Parent Company Only) Financial Information Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Expenses:
Interest expense (Debentures)	$ 3,832	$ 6,435	$ 6,989
Provision for credit loss	45,379	18,843	6,112
Income before federal income taxes and equity in undistributed net income of subsidiaries	211,758	259,954	272,583
Income tax expense	44,439	54,850	56,652
Net income	167,319	205,104	215,931
Parent Company [Member] | Reportable Legal Entities
Income:
Dividends from subsidiaries	130,950	127,750	105,000
Interest income on notes receivable	357	922
Interest income on other investments	(1,126)	(514)	8,208
Other	5	18	1,988
Total income	130,186	128,176	115,196
Expenses:
Interest expense (Debentures)	3,832	6,435	6,989
Provision for credit loss	27
Other	1,988	2,749	2,930
Total expenses	5,847	9,184	9,919
Income before federal income taxes and equity in undistributed net income of subsidiaries	124,339	118,992	105,277
Income tax expense	(1,339)	(1,878)	481
Income before equity in undistributed net income of subsidiaries	125,678	120,870	104,796
Equity in undistributed net income of subsidiaries	41,641	84,234	111,135
Net income	$ 167,319	$ 205,104	$ 215,931

International Bancshares Corp_9

International Bancshares Corporation (Parent Company Only) Financial Information Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities:
Net income	$ 167,319	$ 205,104	$ 215,931
Adjustments to reconcile net income to net cash provided by operating activities:
Investment securities transactions, net	5	12	141
Provision for probable loan losses	45,379	18,843	6,112
Unrealized loss (gain) on equity securities with readily determinable fair values	(107)	(158)	388
Stock compensation expense	743	980	1,035
Increase (decrease) in other liabilities	(13,932)	32,157	24,916
Net cash provided by operating activities	305,133	311,565	229,847
Investing activities:
Net cash (used in) provided by investing activities	(343,705)	(318,058)	379,440
Financing activities:
Redemption of long-term debt		(25,774)
Proceeds from stock transactions	542	1,923	1,522
Payments of cash dividends - common	(69,928)	(68,670)	(49,599)
Repurchase of outstanding common stock warrant			(29,005)
Purchase of treasury stock	(48,878)	(17,845)	(19,042)
Net cash used in financing activities	1,778,990	(53,484)	(557,847)
Increase (decrease) in cash and cash equivalents	1,740,418	(59,977)	51,440
Cash and cash equivalents at beginning of period	256,820	316,797	265,357
Cash and cash equivalents at end of period	1,997,238	256,820	316,797
Parent Company [Member] | Reportable Legal Entities
Operating activities:
Net income	167,319	205,104	215,931
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for probable loan losses	27
Unrealized loss (gain) on equity securities with readily determinable fair values	22	(16)	330
Stock compensation expense	743	980	1,035
Increase (decrease) in other liabilities	2,467	(58)	(1,479)
Equity in undistributed net income of subsidiaries	(41,641)	(84,234)	(111,135)
Net cash provided by operating activities	128,937	121,776	104,682
Investing activities:
Net increase in notes receivable		(12,100)
(Decrease) increase in other assets and other investments	31,289	5,915	(7,891)
Net cash (used in) provided by investing activities	31,289	(6,185)	(7,891)
Financing activities:
Redemption of long-term debt		(25,774)
Proceeds from stock transactions	542	1,923	1,522
Payments of cash dividends - common	(69,928)	(68,670)	(49,599)
Repurchase of outstanding common stock warrant			(29,005)
Purchase of treasury stock	(48,878)	(17,845)	(19,042)
Net cash used in financing activities	(118,264)	(110,366)	(96,124)
Increase (decrease) in cash and cash equivalents	41,962	5,225	667
Cash and cash equivalents at beginning of period	24,290	19,065	18,398
Cash and cash equivalents at end of period	$ 66,252	$ 24,290	$ 19,065