International Bancshares (IBOC) 10-Q 4 May 23 2023 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2023	May 01, 2023
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2023
Document Transition Report	false
Entity File Number	000-09439
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 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
Entity Common Stock, Shares Outstanding		62,114,576
Entity Central Index Key	0000315709
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Amendment Flag	false

Consolidated Statements of Cond

Consolidated Statements of Condition - USD ($)	Mar. 31, 2023	Dec. 31, 2022
Assets
Cash and cash equivalents	$ 1,195,048,000	$ 2,087,724,000
Investment securities:
Held to maturity debt securities (Market value of $3,400 on March 31, 2023 and $3,400 on December 31, 2022)	3,400,000	3,400,000
Available for sale debt securities (Amortized cost of $5,397,131 on March 31, 2023 and $5,018,996 on December 31, 2022)	4,859,818,000	4,417,796,000
Equity securities with readily determinable fair values	5,392,000	5,358,000
Total investment securities	4,868,610,000	4,426,554,000
Loans	7,531,773,000	7,430,603,000
Less allowance for credit losses	(133,557,000)	(125,972,000)
Net loans	7,398,216,000	7,304,631,000
Bank premises and equipment, net	430,436,000	431,612,000
Accrued interest receivable	49,020,000	45,787,000
Other investments	362,105,000	358,910,000
Cash surrender value of life insurance policies	299,379,000	300,589,000
Goodwill	282,532,000	282,532,000
Other assets	249,605,000	263,137,000
Total assets	15,134,951,000	15,501,476,000
Deposits:
Demand-non-interest bearing	5,548,745,000	5,846,055,000
Savings and interest-bearing demand	4,587,639,000	4,745,768,000
Time	2,144,395,000	2,068,184,000
Total deposits	12,280,779,000	12,660,007,000
Securities sold under repurchase agreements	383,502,000	431,191,000
Other borrowed funds	10,895,000	10,944,000
Junior subordinated deferrable interest debentures	134,642,000	134,642,000
Other liabilities	168,725,000	219,933,000
Total liabilities	12,978,543,000	13,456,717,000
Shareholders' equity:
Common shares of $1.00 par value. Authorized 275,000,000 shares; issued 96,423,993 shares on March 31, 2023 and 96,420,456 shares on December 31, 2022	96,424,000	96,420,000
Surplus	154,244,000	154,061,000
Retained earnings	2,758,059,000	2,695,567,000
Accumulated other comprehensive loss	(420,491,000)	(470,497,000)
Total shareholders' equity before treasury stock	2,588,236,000	2,475,551,000
Less cost of shares in treasury, 34,303,617 shares on March 31, 2023 and 34,278,617 on December 31, 2022	(431,828,000)	(430,792,000)
Total shareholders' equity	2,156,408,000	2,044,759,000
Total liabilities and shareholders' equity	$ 15,134,951,000	$ 15,501,476,000

Consolidated Statements of Co_2

Consolidated Statements of Condition (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Consolidated Statements of Condition
Held to maturity, Market value (in dollars)	$ 3,400	$ 3,400
Available for sale, Amortized cost (in dollars)	$ 5,397,131	$ 5,018,996
Common shares, par value (in dollars per share)	$ 1	$ 1
Common shares, Authorized shares	275,000,000	275,000,000
Common shares, issued shares	96,423,993	96,420,456
Treasury, shares	34,303,617	34,278,617

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Interest income:
Loans, including fees	$ 142,270	$ 81,488
Investment securities:
Taxable	29,809	13,190
Tax-exempt	1,578	350
Other interest income	14,492	1,404
Total interest income	188,149	96,432
Interest expense:
Savings deposits	11,694	1,101
Time deposits	6,829	2,504
Securities sold under repurchase agreements	2,142	184
Other borrowings	71	1,888
Junior subordinated deferrable interest debentures	2,228	709
Total interest expense	22,964	6,386
Net interest income	165,185	90,046
Provision for credit losses	8,587	1,481
Net interest income after provision for credit losses	156,598	88,565
Non-interest income:
Other investments, net	2,955	2,882
Other income	3,845	9,092
Total non-interest income	40,362	43,512
Non-interest expense:
Employee compensation and benefits	32,859	31,119
Occupancy	6,326	6,272
Depreciation of bank premises and equipment	5,466	5,475
Professional fees	3,590	2,318
Deposit insurance assessments	4,138	1,057
Net operations, other real estate owned	(1,745)	(408)
Advertising	1,264	1,440
Software and software maintenance	4,969	4,177
Other	11,162	12,668
Total non-interest expense	68,029	64,118
Income before income taxes	128,931	67,959
Provision for income taxes	27,288	14,466
Net income	$ 101,643	$ 53,493
Basic earnings per common share:
Weighted average number of shares outstanding (in shares)	62,142,264	63,352,240
Net income per common share (in dollars per share)	$ 1.64	$ 0.84
Fully diluted earnings per common share:
Weighted average number of shares outstanding (in shares)	62,282,328	63,498,268
Net income per common share (in dollars per share)	$ 1.63	$ 0.84
Services charges on deposit accounts
Non-interest income:
Service charges	$ 17,553	$ 17,257
Other service charges, commissions and fees, Banking
Non-interest income:
Service charges	14,055	12,516
Other service charges, commissions and fees, Non-banking
Non-interest income:
Service charges	$ 1,954	$ 1,765

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Consolidated Statements of Comprehensive Income
Net income	$ 101,643	$ 53,493
Other comprehensive loss, net of tax:
Net unrealized holding gains (losses) on securities available for sale arising during period (net of tax effects of $13,293 and $(46,029))	50,006	(173,156)
Other comprehensive loss, net of tax	50,006	(173,156)
Comprehensive income (loss)	$ 151,649	$ (119,663)

Consolidated Statements of Co_3

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Consolidated Statements of Comprehensive Income
Net unrealized holding gains (losses) on securities available for sale arising during period, tax effects	$ 13,293	$ (46,029)

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Total
Balance at Dec. 31, 2021	$ 96,351	$ 152,144	$ 2,470,710	$ (31,980)	$ (378,744)	$ 2,308,481
Balance (in shares) at Dec. 31, 2021	96,351
Increase (decrease) in shareholders' equity
Net income			53,493			53,493
Dividends:
Payable/Cash			(38,026)			(38,026)
Purchase of treasury stock					(3,380)	(3,380)
Exercise of stock options	$ 6	140				146
Exercise of stock options (in shares)	6
Stock compensation expense recognized in earnings		121				121
Other comprehensive loss, net of tax:
Net change in unrealized gains and losses on available for sale securities, net of reclassification adjustments				(173,156)		(173,156)
Balance at Mar. 31, 2022	$ 96,357	152,405	2,486,177	(205,136)	(382,124)	2,147,679
Balance (in shares) at Mar. 31, 2022	96,357
Balance at Dec. 31, 2022	$ 96,420	154,061	2,695,567	(470,497)	(430,792)	2,044,759
Balance (in shares) at Dec. 31, 2022	96,420
Increase (decrease) in shareholders' equity
Net income			101,643			101,643
Dividends:
Payable/Cash			(39,151)			(39,151)
Purchase of treasury stock					(1,036)	(1,036)
Exercise of stock options	$ 4	81				85
Exercise of stock options (in shares)	4
Stock compensation expense recognized in earnings		102				102
Other comprehensive loss, net of tax:
Net change in unrealized gains and losses on available for sale securities, net of reclassification adjustments				50,006		50,006
Balance at Mar. 31, 2023	$ 96,424	$ 154,244	$ 2,758,059	$ (420,491)	$ (431,828)	$ 2,156,408
Balance (in shares) at Mar. 31, 2023	96,424

Consolidated Statements of Sh_2

Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Consolidated Statements of Shareholders' Equity
Cash Dividends (in dollars per share)	$ 0.63	$ 0.60
Purchase of treasury stock (in shares)	25,000	83,066

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating activities:
Net income	$ 101,643,000	$ 53,493,000
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit loss	8,587,000	1,481,000
Specific reserve, other real estate owned	250,000
Depreciation of bank premises and equipment	5,466,000	5,475,000
(Gain) loss on sale of bank premises and equipment		(2,991,000)
Gain on sale of other real estate owned	(2,372,000)	(777,000)
Accretion of investment securities discounts	(589,000)	(235,000)
Amortization of investment securities premiums	1,817,000	5,262,000
Unrealized (gain) loss on equity securities with readily determinable fair values	(34,000)	269,000
Stock based compensation expense	102,000	121,000
(Earnings) from affiliates and other investments	(802,000)	(2,474,000)
Deferred tax (benefit) expense	(1,841,000)	80,000
(Increase) decrease in accrued interest receivable	(3,233,000)	3,038,000
Increase (decrease) in other assets	1,277,000	(4,455,000)
Increase in other liabilities	32,419,000	20,810,000
Net cash provided by operating activities	142,690,000	79,097,000
Investing activities:
Proceeds from maturities of securities	1,200,000	1,075,000
Proceeds from sales and calls of available for sale securities	450,000	0
Purchases of available for sale securities	(595,184,000)	(362,746,000)
Principal collected on mortgage-backed securities	134,171,000	207,302,000
Net (increase) decrease in loans	(102,525,000)	159,246,000
Purchases of other investments	(9,935,000)	(42,043,000)
Distributions from other investments	5,124,000	1,583,000
Purchases of bank premises and equipment	(4,290,000)	(2,486,000)
Proceeds from sales of bank premises and equipment		6,461,000
Proceeds from sales of other real estate owned	2,691,000	4,898,000
Net cash used in investing activities	(568,298,000)	(26,710,000)
Financing activities:
Net (decrease) increase in non-interest bearing demand deposits	(297,310,000)	198,680,000
Net decrease in savings and interest-bearing demand deposits	(158,129,000)	(28,897,000)
Net increase in time deposits	76,211,000	7,676,000
Net (decrease) increase in securities sold under repurchase agreements	(47,689,000)	50,419,000
Net decrease in other borrowed funds	(49,000)	(48,000)
Purchase of treasury stock	(1,036,000)	(3,380,000)
Proceeds from stock transactions	85,000	146,000
Payments of cash dividends	(39,151,000)	(38,026,000)
Net cash (used in) provided by financing activities	(467,068,000)	186,570,000
(Decrease) increase in cash and cash equivalents	(892,676,000)	238,957,000
Cash and cash equivalents at beginning of period	2,087,724,000	3,209,242,000
Cash and cash equivalents at end of period	1,195,048,000	3,448,199,000
Supplemental cash flow information:
Interest paid	19,731,000	6,297,000
Non-cash investing and financing activities:
Net transfers from loans to other real estate owned	$ 353,000
Net transfers from bank premises and equipment to other assets		$ 2,476,000

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2023
Basis of Presentation
Basis of Presentation	Note 1 — Basis of Presentation ​ Our accounting and reporting policies conform to accounting principles generally accepted in the United States of America and to general practices within the banking industry. Our consolidated financial statements include the accounts of International Bancshares Corporation, and our wholly-owned bank subsidiaries, International Bank of Commerce, Laredo (“IBC”), Commerce Bank, International Bank of Commerce, Zapata, International Bank of Commerce, Brownsville, International Bank of Commerce, Oklahoma (the “Subsidiary Banks”) and our wholly-owned non-bank subsidiaries, IBC Trading Company, Premier Tierra Holdings, Inc., IBC Charitable and Community Development Corporation, Emerald Galveston Holdings, LLC, IBC Capital Corporation, and Diamond Beach Holdings, LLC. Our consolidated financial statements are unaudited, but include all adjustments, which, in the opinion of management, are necessary for a fair presentation of the results of the periods presented. All such adjustments were of a normal and recurring nature. These financial statements should be read in conjunction with the financial statements and the notes thereto in our latest Annual Report to Shareholders on Form ARS for the fiscal year ended December 31, 2022, furnished to the U.S. Securities and Exchange Commission (“SEC”) on April 17, 2023 (our “2022 Annual Report”). Our consolidated statement of condition at December 31, 2022 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by accounting principles generally accepted in the United States of America (“US GAAP”) for complete financial statements. Certain reclassifications have been made to make prior periods comparable. Operating results for the three months ended March 31, 2023 are not necessarily indicative of the results for the year ending December 31, 2023 or any future period. ​ 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 statements presented in this report. We have ​ 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. ​

Fair Value

Fair Value	3 Months Ended
	Mar. 31, 2023
Fair Value
Fair Value	Note 2 — Fair Value Measurements ​ 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 inputs, 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. ​ ​ The following table represents assets and liabilities reported on the consolidated balance sheets at their fair value on a recurring basis as of March 31, 2023 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 ​ ​ ​ March 31, 2023 ​ (Level 1) ​ (Level 2) ​ (Level 3) ​ Measured on a recurring basis: ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Available for sale debt securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury securities ​ $ 49,925 ​ $ — ​ $ 49,925 ​ $ — ​ Residential mortgage-backed securities ​ ​ 4,647,229 ​ ​ — ​ ​ 4,647,229 ​ ​ — ​ States and political subdivisions ​ 162,664 ​ — ​ 162,664 ​ — ​ Equity Securities ​ 5,392 ​ 5,392 ​ — ​ — ​ ​ ​ $ 4,865,210 ​ $ 5,392 ​ $ 4,859,818 ​ $ — ​ ​ The following table represents assets and liabilities reported on the consolidated balance sheets at their fair value on a recurring basis as of December 31, 2022 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, 2022 ​ (Level 1) ​ (Level 2) ​ (Level 3) ​ Measured on a recurring basis: ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Available for sale securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury securities ​ $ 49,393 ​ $ — ​ $ 49,393 ​ $ — ​ Residential mortgage-backed securities ​ ​ 4,209,212 ​ ​ — ​ ​ 4,209,212 ​ ​ — ​ States and political subdivisions ​ 159,191 ​ — ​ 159,191 ​ — ​ Equity Securities ​ 5,358 ​ 5,358 ​ — ​ — ​ ​ ​ $ 4,423,154 ​ $ 5,358 ​ $ 4,417,796 ​ $ — ​ ​ Available-for-sale debt securities are classified within Level 1 or 2 of the valuation hierarchy. Equity securities with readily determinable fair values are classified within Level 1. For debt investments 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 assets and financial liabilities are measured at fair value on a non-recurring basis. The instruments are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (for example, when there is evidence of impairment). ​ The following table represents financial instruments measured at fair value on a non-recurring basis as of and for the period ended March 31, 2023 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 ​ ​ Period ended ​ Identical ​ Observable ​ Unobservable ​ Provision ​ ​ March 31, ​ Assets ​ Inputs ​ Inputs ​ During ​ ​ 2023 ​ (Level 1) ​ (Level 2) ​ (Level 3) ​ Period Measured on a non-recurring basis: ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Watch-List doubtful loans ​ $ 29,894 ​ $ — ​ $ — ​ $ 29,894 ​ $ 1,000 Other real estate owned ​ ​ 752 ​ ​ — ​ ​ — ​ ​ 752 ​ ​ 250 ​ The following table represents financial instruments measured at fair value on a non-recurring basis as of and for the period ended December 31, 2022 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 ​ ​ Year ended ​ for Identical ​ Observable ​ Unobservable ​ Provision ​ ​ December 31, ​ Assets ​ Inputs ​ Inputs ​ During ​ ​ 2022 ​ (Level 1) ​ (Level 2) ​ (Level 3) ​ Period Measured on a non-recurring basis: ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Watch-List doubtful loans ​ $ 30,743 ​ $ — ​ $ — ​ $ 30,743 ​ $ 2,346 Other real estate owned ​ 5,653 ​ — ​ — ​ 5,653 ​ 1,627 ​ 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. 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 allowance for credit losses (“ACL”). The fair value of the loan is based on the fair value of the collateral, as determined through either an appraisal or internal 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 internal 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 March 31, 2023, we had had an internal evaluation performed within the immediately preceding twelve months. As of December 31, 2022, we had approximately ​ Our determination to either seek an appraisal or to perform an internal 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 analysis of the doubtful loan. 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, if necessary. The fair value is reviewed periodically, and subsequent write-downs are made through a charge to operations, accordingly. Other real estate owned is included in other assets on the consolidated financial statements. For the three months ended March 31, 2023 and the twelve months ended December 31, 2022, we recorded $0 and $2,000, respectively, i n charges to the ACL in connection with loans transferred to other real estate owned. For the three months ended March 31, 2023 and the twelve months ended December 31, 2022, we recorded and ​ The fair value estimates, methods, and assumptions for our financial instruments at March 31, 2023 and December 31, 2022 are outlined below. ​ Cash and Cash Equivalents ​ For these short-term instruments, the carrying amount is a reasonable estimate of fair value. ​ Time Deposits with Banks ​ The carrying amounts of time deposits with banks approximate fair value. ​ Investment Securities Held-to-Maturity ​ The carrying amounts of investments held-to-maturity approximate fair value. ​ Investment Securities ​ For 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 6. ​ 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 March 31, 2023 and December 31, 2022, the carrying amount of fixed rate performing loans was ​ 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 March 31, 2023 and December 31, 2022. The fair value of time deposits is based on the discounted value of contractual cashflows. The discount rate is based on currently offered rates. Time deposits are within Level 3 of the fair value hierarchy. At March 31, 2023 and December 31, 2022, the carrying amount of time deposits was ​ 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 March 31, 2023 and December 31, 2022. ​ 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 March 31, 2023 and December 31, 2022. ​ Other Borrowed Funds ​ We currently have long-term borrowings issued from the Federal Home Loan Bank (“FHLB”). The long-term borrowings outstanding at March 31, 2023 and December 31, 2022 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 March 31, 2023 and December 31, 2022, the carrying amount of the fixed rate long-term FHLB borrowings was , 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 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.

Loans

Loans	3 Months Ended
	Mar. 31, 2023
Loans
Loans	Note 3 — Loans ​ A summary of loans, by loan type at March 31, 2023 and December 31, 2022 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ ​ ​ 2023 ​ 2022 ​ ​ ​ (Dollars in Thousands) ​ Commercial, financial and agricultural $ 4,370,745 $ 4,373,373 ​ Real estate - mortgage ​ 858,909 ​ 865,994 ​ Real estate - construction ​ 2,081,138 ​ 1,989,669 ​ Consumer ​ 43,390 ​ 41,592 ​ Foreign ​ 177,591 ​ 159,975 ​ Total loans ​ $ 7,531,773 ​ $ 7,430,603 ​ ​

Allowance for Credit Losses

Allowance for Credit Losses	3 Months Ended
	Mar. 31, 2023
Allowance for Credit Losses
Allowance for Credit Losses	Note 4 — Allowance for Credit Losses ​ ​ The allowance for credit losses (“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. This category includes loans secured by farmland, multifamily properties, owner occupied commercial properties, and non-owner occupied commercial properties. Owner occupied commercial properties include warehouses often along the border for import/export operations, office space where the borrower is the primary tenant, restaurants and other single-tenant retail. Non-owner occupied commercial properties include hotels, retail centers, office and professional buildings, and leased warehouses. These loans carry risk of repayment when market values deteriorate, the business experiences turnover in key management, the business has an inability to attract or keep occupancy levels stable, or when the market experiences an exit of a specific business type that is significant to the local economy, such as a manufacturing plant. 1-4 family mortgages. This category includes both first and second lien mortgages for the purpose of home purchases or refinancing of existing mortgage loans. A small portion of this loan category is related to home equity lines of credits, lots purchases, and home construction. Loan repayments may be affected by unemployment or underemployment and deteriorating market values of real estate. ​ 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, (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 transactions in the allowance for credit loan losses by loan class is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2023 ​ ​ ​ ​ ​ ​ 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, 2022 ​ $ 26,728 ​ $ 44,684 ​ $ 36,474 ​ $ 3,794 ​ $ 4,759 ​ $ 8,284 ​ $ 281 ​ $ 968 ​ $ 125,972 ​ Losses charged to allowance ​ (1,971) ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (1) ​ ​ (61) ​ ​ — ​ (2,033) ​ Recoveries credited to allowance ​ 625 ​ ​ 311 ​ ​ 5 ​ ​ — ​ ​ 7 ​ ​ 77 ​ ​ 6 ​ ​ — ​ 1,031 ​ Net (losses) recoveries charged to allowance ​ (1,346) ​ 311 ​ 5 ​ — ​ 7 ​ 76 ​ (55) ​ — ​ (1,002) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Credit loss expense ​ 2,406 ​ ​ 5,938 ​ ​ 77 ​ ​ 190 ​ ​ (207) ​ ​ (3) ​ ​ 65 ​ ​ 121 ​ 8,587 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at March 31, 2023 ​ $ 27,788 ​ $ 50,933 ​ $ 36,556 ​ $ 3,984 ​ $ 4,559 ​ $ 8,357 ​ $ 291 ​ $ 1,089 ​ $ 133,557 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2022 ​ ​ ​ ​ ​ ​ 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, 2021 ​ $ 23,178 ​ $ 35,390 ​ $ 35,654 ​ $ 3,291 ​ $ 4,073 ​ $ 7,754 ​ $ 272 ​ $ 762 ​ $ 110,374 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Losses charged to allowance ​ (2,112) ​ ​ (2) ​ ​ — ​ ​ — ​ ​ (99) ​ ​ (28) ​ ​ (88) ​ ​ — ​ (2,329) ​ Recoveries credited to allowance ​ 602 ​ ​ 2 ​ ​ 8 ​ ​ — ​ ​ 30 ​ ​ 48 ​ ​ 11 ​ ​ — ​ 701 ​ Net (losses) recoveries charged to allowance ​ (1,510) ​ — ​ 8 ​ — ​ (69) ​ 20 ​ (77) ​ — ​ (1,628) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Credit loss expense ​ 2,233 ​ ​ 982 ​ ​ (808) ​ ​ (229) ​ ​ 12 ​ ​ (728) ​ ​ 69 ​ ​ (50) ​ 1,481 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at March 31, 2022 ​ $ 23,901 ​ $ 36,372 ​ $ 34,854 ​ $ 3,062 ​ $ 4,016 ​ $ 7,046 ​ $ 264 ​ $ 712 ​ $ 110,227 ​ ​ The credit loss charged to expense for the three months ended March 31, 2023 has increased from the same period of 2022 in order to provide some protection from potential losses in our loan portfolio given the high level of uncertainty in the economy and a potential economic recession on the horizon. We have increased the severity of some of the qualitative loss factors in certain pools of the portfolio to encompass the economic uncertainty, resulting in an increase in the required ACL. The pool specific qualitative loss factors management deemed appropriate for the ACL calculation at December 31, 2022 remained constant in the March 31, 2023 ACL calculation. The pool specific qualitative loss factors management deemed appropriate for the ACL calculation at December 31, 2022 remained constant in the March 31, 2023 ACL calculation. ​ The tables below provides additional information on the balance of loans individually or collectively evaluated for impairment and their related allowance, by loan class as of March 31, 2023 and December 31, 2022: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2023 ​ ​ ​ Loans Individually ​ Loans Collectively ​ ​ ​ Evaluated For ​ Evaluated For ​ ​ ​ Impairment ​ Impairment ​ ​ ​ Recorded ​ ​ ​ ​ Recorded ​ ​ ​ ​ ​ ​ Investment ​ Allowance ​ Investment ​ Allowance ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial $ 30,529 $ 3,375 $ 1,467,573 $ 24,413 ​ Commercial real estate: other construction & land development ​ 20,481 ​ 70 ​ 2,060,657 ​ 50,863 ​ Commercial real estate: farmland & commercial ​ 297 ​ — ​ 2,562,801 ​ 36,556 ​ Commercial real estate: multifamily ​ 110 ​ — ​ 309,435 ​ 3,984 ​ Residential: first lien ​ 74 ​ — ​ 419,481 ​ 4,559 ​ Residential: junior lien ​ 318 ​ — ​ 439,036 ​ 8,357 ​ Consumer ​ — ​ — ​ 43,390 ​ 291 ​ Foreign ​ — ​ — ​ 177,591 ​ 1,089 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 51,809 ​ $ 3,445 ​ $ 7,479,964 ​ $ 130,112 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ ​ ​ Loans Individually ​ Loans Collectively ​ ​ ​ Evaluated For ​ Evaluated For ​ ​ ​ Impairment ​ Impairment ​ ​ ​ Recorded ​ ​ ​ ​ Recorded ​ ​ ​ ​ ​ ​ Investment ​ Allowance ​ Investment ​ Allowance ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial $ 30,747 $ 2,375 $ 1,468,006 $ 24,353 ​ Commercial real estate: other construction & land development ​ 20,483 ​ 70 ​ 1,969,186 ​ 44,614 ​ Commercial real estate: farmland & commercial ​ 94 ​ — ​ 2,568,025 ​ 36,474 ​ Commercial real estate: multifamily ​ 117 ​ — ​ 306,384 ​ 3,794 ​ Residential: first lien ​ 77 ​ — ​ 425,647 ​ 4,759 ​ Residential: junior lien ​ 312 ​ — ​ 439,958 ​ 8,284 ​ Consumer ​ — ​ — ​ 41,592 ​ 281 ​ Foreign ​ — ​ — ​ 159,975 ​ 968 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 51,830 ​ $ 2,445 ​ $ 7,378,773 ​ $ 123,527 ​ ​ The table below provides additional information on loans accounted for on a non-accrual basis by loan class at March 31, 2023 and December 31, 2022: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2023 ​ December 31, 2022 ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ ​ ​ ​ Commercial $ 30,529 $ 30,747 ​ Commercial real estate: other construction & land development ​ 20,481 ​ 20,483 ​ Commercial real estate: farmland & commercial ​ 297 ​ 94 ​ Commercial real estate: multifamily ​ 110 ​ 117 ​ Residential: first lien ​ 215 ​ 207 ​ Total non-accrual loans ​ $ 51,632 ​ $ 51,648 ​ ​ We adopted the provisions of Accounting Standards Update 2022-02, Financial Instruments – Credit Losses (Topic 326): Troubled Debt Restructurings and Vintage Disclosures (“ASU 2022-02”) on January 1, 2023. ASU 2022-02 eliminates the accounting guidance for troubled debt restructurings in existing guidance and enhances disclosure requirements for certain loan refinancings and restructurings when a borrower is experiencing financial difficulty. Additionally, ASU 2022-02 requires entities to disclose current period gross write-offs by year of origination for financing receivables and net investments in leases. The adoption of ASU 2022-22 did not have a significant impact to our consolidated financial statements. ​ We occasionally provide modifications to borrowers experiencing financial difficulties. Modifications may include certain concessions that we must evaluate under ASU 2022-02 to determine the need for disclosure. Concessions to borrowers experiencing financial difficulties that would require disclosure include principal forgiveness, term extension, an other-than-insignificant payment delay, an interest rate reduction or a combination of these concessions. For the three months ended March 31, 2023, we did not provide any modifications under these circumstances to any borrower experiencing financial difficulty. ​ Under guidance in effect prior to January 1, 2023, the following table details loans accounted for as “troubled debt restructuring,” segregated by loan class. Loans accounted for as troubled debt restructuring are included in Watch List—Doubtful loans. ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ Residential: first lien ​ $ 1,642 ​ Residential: junior lien ​ ​ 714 ​ Consumer ​ ​ 802 ​ Foreign ​ ​ 55 ​ Total troubled debt restructuring ​ $ 3,213 ​ ​ ​ 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 ​ While our management believes 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 can be made only on a subjective basis. It is the judgment of our management that the ACL at March 31, 2023 was adequate to absorb probable losses from loans in the portfolio at that date. ​ The following tables present information regarding the aging of past due loans by loan class at March 31, 2023 and December 31, 2022: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 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 $ 2,162 $ 217 $ 30,549 $ 121 $ 32,928 $ 1,465,174 $ 1,498,102 ​ Commercial real estate: other construction & land development ​ 14,242 ​ — ​ 19,982 ​ — ​ 34,224 ​ 2,046,914 ​ 2,081,138 ​ Commercial real estate: farmland & commercial ​ 594 ​ 4,565 ​ — ​ — ​ 5,159 ​ 2,557,940 ​ 2,563,099 ​ Commercial real estate: multifamily ​ 233 ​ — ​ — ​ — ​ 233 ​ 309,311 ​ 309,544 ​ Residential: first lien ​ 1,189 ​ 1,153 ​ 3,097 ​ 2,864 ​ 5,439 ​ 414,116 ​ 419,555 ​ Residential: junior lien ​ 1,235 ​ 258 ​ 2,051 ​ 2,051 ​ 3,544 ​ 435,810 ​ 439,354 ​ Consumer ​ 270 ​ 30 ​ 12 ​ 12 ​ 312 ​ 43,078 ​ 43,390 ​ Foreign ​ 598 ​ 11 ​ 581 ​ 581 ​ 1,190 ​ 176,401 ​ 177,591 ​ Total past due loans ​ $ 20,523 ​ $ 6,234 ​ $ 56,272 ​ $ 5,629 ​ $ 83,029 ​ $ 7,448,744 ​ $ 7,531,773 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 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 ​ $ 1,732 $ 258 $ 1,014 $ 59 $ 3,004 $ 1,495,750 $ 1,498,754 ​ Commercial real estate: other construction & land development ​ 1,130 ​ — ​ — ​ — ​ 1,130 ​ 1,988,539 ​ 1,989,669 ​ Commercial real estate: farmland & commercial ​ 1,744 ​ 117 ​ — ​ — ​ 1,861 ​ 2,566,257 ​ 2,568,118 ​ Commercial real estate: multifamily ​ — ​ — ​ — ​ — ​ — ​ 306,501 ​ 306,501 ​ Residential: first lien ​ 2,023 ​ 1,068 ​ 4,189 ​ 4,061 ​ 7,280 ​ 418,444 ​ 425,724 ​ Residential: junior lien ​ 925 ​ 771 ​ 1,717 ​ 1,717 ​ 3,413 ​ 436,857 ​ 440,270 ​ Consumer ​ 281 ​ 14 ​ 7 ​ 7 ​ 302 ​ 41,290 ​ 41,592 ​ Foreign ​ 717 ​ 23 ​ 288 ​ 288 ​ 1,028 ​ 158,947 ​ 159,975 ​ Total past due loans ​ $ 8,552 ​ $ 2,251 ​ $ 7,215 ​ $ 6,132 ​ $ 18,018 ​ $ 7,412,585 ​ $ 7,430,603 ​ ​ The increase in Commercial loans past due 90 days or greater at March 31, 2023 can be primarily attributed to a loan secured by equipment and other assets used in the oil and gas industry as well as oil and gas production that is on non-accrual. The increase in Commercial Real Estate: Other Construction & Land Development loans past due 30 – 59 days can be primarily attributed to three relationships secured by commercial properties that were matured and in the process of being renewed. The increase in Commercial Real Estate: Other Construction & Land Development loans past due 90 days or greater can be primarily attributed to a loan secured by commercial property that is on non-accrual. ​ A summary of the loan portfolio by credit quality indicator by loan class and by year of origination at March 31, 2023 and December 31, 2022 is presented below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2023 2022 2021 2020 2019 Prior Total ​ ​ ​ (Dollars in Thousands) ​ Balance at March 31, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 263,913 ​ $ 530,585 ​ $ 452,955 ​ $ 87,039 ​ $ 32,481 ​ $ 68,318 ​ $ 1,435,291 ​ Special Review ​ ​ — ​ ​ 371 ​ ​ 201 ​ ​ — ​ ​ — ​ ​ — ​ ​ 572 ​ Watch List - Substandard ​ ​ 218 ​ ​ 28,889 ​ ​ 130 ​ ​ — ​ ​ 19 ​ ​ 2,454 ​ ​ 31,710 ​ Watch List - Doubtful ​ ​ — ​ ​ 29,789 ​ ​ — ​ ​ 739 ​ ​ — ​ ​ 1 ​ ​ 30,529 ​ Total Commercial ​ $ 264,131 ​ $ 589,634 ​ $ 453,286 ​ $ 87,778 ​ $ 32,500 ​ $ 70,773 ​ $ 1,498,102 ​ Commercial real estate: other construction & land development ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 341,573 ​ $ 840,168 ​ $ 530,211 ​ $ 186,626 ​ $ 124,467 ​ $ 37,404 ​ $ 2,060,449 ​ Special Review ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 208 ​ ​ — ​ ​ 208 ​ Watch List - Doubtful ​ ​ — ​ ​ 19,982 ​ ​ 407 ​ ​ 92 ​ ​ — ​ ​ — ​ ​ 20,481 ​ Total Commercial real estate: other construction & land development ​ $ 341,573 ​ $ 860,150 ​ $ 530,618 ​ $ 186,718 ​ $ 124,675 ​ $ 37,404 ​ $ 2,081,138 ​ Commercial real estate: farmland & commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 294,941 ​ $ 723,848 ​ $ 534,498 ​ $ 353,714 ​ $ 228,974 ​ $ 336,205 ​ $ 2,472,180 ​ Special Review ​ ​ — ​ ​ 173 ​ ​ — ​ ​ 835 ​ ​ — ​ ​ — ​ ​ 1,008 ​ Watch List - Pass ​ ​ — ​ ​ 16,986 ​ ​ 243 ​ ​ — ​ ​ — ​ ​ — ​ ​ 17,229 ​ Watch List - Substandard ​ ​ — ​ ​ 54,038 ​ ​ 4,556 ​ ​ 2,486 ​ ​ 93 ​ ​ 11,212 ​ ​ 72,385 ​ Watch List - Doubtful ​ ​ — ​ ​ 91 ​ ​ — ​ ​ — ​ ​ — ​ ​ 206 ​ ​ 297 ​ Total Commercial real estate: farmland & commercial ​ $ 294,941 ​ $ 795,136 ​ $ 539,297 ​ $ 357,035 ​ $ 229,067 ​ $ 347,623 ​ $ 2,563,099 ​ Commercial real estate: multifamily ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 45,117 ​ $ 125,030 ​ $ 50,142 ​ $ 58,802 ​ $ 11,427 ​ $ 18,916 ​ $ 309,434 ​ Watch List - Doubtful ​ ​ — ​ ​ 110 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 110 ​ Total Commercial real estate: multifamily ​ $ 45,117 ​ $ 125,140 ​ $ 50,142 ​ $ 58,802 ​ $ 11,427 ​ $ 18,916 ​ $ 309,544 ​ Residential: first lien ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 71,028 ​ $ 97,907 ​ $ 76,400 ​ $ 45,354 ​ $ 32,016 ​ $ 96,356 ​ $ 419,061 ​ Watch List - Substandard ​ ​ — ​ ​ — ​ ​ 354 ​ ​ 66 ​ ​ — ​ ​ — ​ ​ 420 ​ Watch List - Doubtful ​ ​ — ​ ​ 74 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 74 ​ Total Residential: first lien ​ $ 71,028 ​ $ 97,981 ​ $ 76,754 ​ $ 45,420 ​ $ 32,016 ​ $ 96,356 ​ $ 419,555 ​ Residential: junior lien ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 15,944 ​ $ 90,944 ​ $ 103,512 ​ $ 86,758 ​ $ 39,295 ​ $ 102,583 ​ $ 439,036 ​ Watch List- Doubtful ​ ​ — ​ ​ 318 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 318 ​ Total Residential: junior lien ​ $ 15,944 ​ $ 91,262 ​ $ 103,512 ​ $ 86,758 ​ $ 39,295 ​ $ 102,583 ​ $ 439,354 ​ Residential: junior lien ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consumer ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 12,176 ​ $ 24,278 ​ $ 4,412 ​ $ 542 ​ $ 344 ​ $ 1,638 ​ $ 43,390 ​ Total Consumer ​ $ 12,176 ​ $ 24,278 ​ $ 4,412 ​ $ 542 ​ $ 344 ​ $ 1,638 ​ $ 43,390 ​ Foreign ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 27,135 ​ $ 119,493 ​ $ 15,902 ​ $ 4,996 ​ $ 4,479 ​ $ 5,586 ​ $ 177,591 ​ Total Foreign ​ $ 27,135 ​ $ 119,493 ​ $ 15,902 ​ $ 4,996 ​ $ 4,479 ​ $ 5,586 ​ $ 177,591 ​ Total Loans ​ $ 1,072,045 ​ $ 2,703,074 ​ $ 1,773,923 ​ $ 828,049 ​ $ 473,803 ​ $ 680,879 ​ $ 7,531,773 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 2021 2020 2019 2018 Prior Total ​ ​ (Dollars in Thousands) Balance at December 31, 2022 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 736,462 ​ $ 524,879 ​ $ 96,401 ​ $ 35,917 ​ $ 43,792 ​ $ 29,464 ​ $ 1,466,915 Special Review ​ ​ 377 ​ ​ 213 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 590 Watch List - Substandard ​ ​ 161 ​ ​ 149 ​ ​ 143 ​ ​ — ​ ​ 49 ​ ​ — ​ ​ 502 Watch List - Doubtful ​ ​ 29,789 ​ ​ — ​ ​ 954 ​ ​ — ​ ​ — ​ ​ 4 ​ ​ 30,747 Total Commercial ​ $ 766,789 ​ $ 525,241 ​ $ 97,498 ​ $ 35,917 ​ $ 43,841 ​ $ 29,468 ​ $ 1,498,754 Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial real estate: other construction & land development ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 913,675 ​ $ 666,347 ​ $ 173,824 ​ $ 174,897 ​ $ 35,069 ​ $ 5,165 ​ $ 1,968,977 Special Review ​ ​ — ​ ​ — ​ ​ — ​ ​ 209 ​ ​ — ​ ​ — ​ ​ 209 Watch List - Doubtful ​ ​ 19,982 ​ ​ 407 ​ ​ 94 ​ ​ — ​ ​ — ​ ​ — ​ ​ 20,483 Total Commercial real estate: other construction & land development ​ $ 933,657 ​ $ 666,754 ​ $ 173,918 ​ $ 175,106 ​ $ 35,069 ​ $ 5,165 ​ $ 1,989,669 Commercial real estate: farmland & commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 811,117 ​ $ 584,134 ​ $ 456,200 ​ $ 232,537 ​ $ 325,214 ​ $ 81,295 ​ $ 2,490,497 Special Review ​ ​ 2,855 ​ ​ — ​ ​ 842 ​ ​ — ​ ​ — ​ ​ — ​ ​ 3,697 Watch List - Pass ​ ​ 17,060 ​ ​ 247 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 17,307 Watch List - Substandard ​ ​ 2,275 ​ ​ — ​ ​ 54,152 ​ ​ 96 ​ ​ — ​ ​ — ​ ​ 56,523 Watch List - Doubtful ​ ​ 94 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 94 Total Commercial real estate: farmland & commercial ​ $ 833,401 ​ $ 584,381 ​ $ 511,194 ​ $ 232,633 ​ $ 325,214 ​ $ 81,295 ​ $ 2,568,118 Commercial real estate: multifamily ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 127,680 ​ $ 87,469 ​ $ 59,035 ​ $ 12,026 ​ $ 5,490 ​ $ 14,684 ​ $ 306,384 Watch List - Doubtful ​ ​ 117 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 117 Total Commercial real estate: multifamily ​ $ 127,797 ​ $ 87,469 ​ $ 59,035 ​ $ 12,026 ​ $ 5,490 ​ $ 14,684 ​ $ 306,501 Residential: first lien ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 138,771 ​ $ 82,466 ​ $ 49,591 ​ $ 40,985 ​ $ 33,814 ​ $ 79,660 ​ $ 425,287 Watch List - Substandard ​ ​ — ​ ​ 360 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 360 Watch List - Doubtful ​ ​ 77 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 77 Total Residential: first lien ​ $ 138,848 ​ $ 82,826 ​ $ 49,591 ​ $ 40,985 ​ $ 33,814 ​ $ 79,660 ​ $ 425,724 Residential: junior lien ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 92,256 ​ $ 108,815 ​ $ 91,130 ​ $ 41,273 ​ $ 21,975 ​ $ 84,509 ​ $ 439,958 Watch List- Doubtful ​ ​ — ​ ​ 312 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 312 Total Residential: junior lien ​ $ 92,256 ​ $ 109,127 ​ $ 91,130 ​ $ 41,273 ​ $ 21,975 ​ $ 84,509 ​ $ 440,270 Consumer ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 31,962 ​ $ 6,603 ​ $ 897 ​ $ 489 ​ $ 28 ​ $ 1,613 ​ $ 41,592 Total Consumer ​ $ 31,962 ​ $ 6,603 ​ $ 897 ​ $ 489 ​ $ 28 ​ $ 1,613 ​ $ 41,592 Foreign ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 124,265 ​ $ 19,082 ​ $ 5,362 ​ $ 4,848 ​ $ 3,417 ​ $ 3,001 ​ $ 159,975 Total Foreign ​ $ 124,265 ​ $ 19,082 ​ $ 5,362 ​ $ 4,848 ​ $ 3,417 ​ $ 3,001 ​ $ 159,975 Total Loans ​ $ 3,048,975 ​ $ 2,081,483 ​ $ 988,625 ​ $ 543,277 ​ $ 468,848 ​ $ 299,395 ​ $ 7,430,603 ​ ​ The increase in Watch-List Substandard Commercial loans at March 31, 2023 compared to December 31, 2022 can be primarily attributed to a loan secured by accounts receivable that was downgraded from Pass. The increase in Watch-List Substandard Commercial Real Estate: Farmland & Commercial loans at March 31, 2022 compared to December 31, 2022 can be primarily attributed to the downgrade from Pass of two loans that are secured by real estate.

Stock Options and Stock Appreci

Stock Options and Stock Appreciation Rights	3 Months Ended
	Mar. 31, 2023
Stock Options and Stock Appreciation Rights
Stock Options	Note 5 — Stock Options ​ On April 5, 2012, the Board of Directors adopted the 2012 International Bancshares Corporation Stock Option Plan (the “2012 Plan”). There were 800,000 shares of common stock available for stock option grants under the 2012 Plan, which were qualified incentive stock options (“ISOs”) or non-qualified stock options. 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 . On April 4, 2022 the 2012 plan expired and was not renewed. ​ A summary of option activity under the stock option plan for the three months ended March 31, 2023 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, 2022 461,822 ​ $ 29.67 ​ ​ ​ ​ ​ ​ Plus: Options granted — ​ — ​ ​ ​ ​ ​ ​ Less: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options exercised 3,537 ​ 24.00 ​ ​ ​ ​ ​ ​ Options expired — ​ — ​ ​ ​ ​ ​ ​ Options forfeited 2,938 ​ 36.51 ​ ​ ​ ​ ​ ​ Options outstanding at March 31, 2023 455,347 ​ 29.67 3.82 ​ $ 5,987 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options fully vested and exercisable at March 31, 2023 257,932 ​ $ 25.20 2.06 ​ $ 4,545 ​ ​ Stock-based compensation expense included in the consolidated statements of income for the three months ended March 31, 2023 and March 31, 2022 was $102,000 and $121,000 , respectively. As of March 31, 2023, there was approximately ​ On April 18, 2022, the Board of Directors adopted the 2022 International Bancshares Corporation Stock Appreciation Rights Plan (the “SAR Plan”). There are shares of underlying common stock that may be used for stock appreciation right (“SAR”) grants under the plan, however, no actual shares will be granted. Upon exercise, the SAR will be settled in cash. SARs granted may be exercisable for a period of up to period. As of March 31, 2023, a total of A summary of activity under the SAR Plan for the three months ended March 31, 2023 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ Weighted ​ average ​ ​ ​ ​ ​ Number of ​ average ​ remaining ​ Aggregate ​ ​ stock appreciation ​ exercise ​ contractual ​ intrinsic ​ ​ rights ​ price ​ term (years) ​ value ($) ​ ​ ​ ​ ​ ​ ​ ​ ​ (in Thousands) Stock appreciation rights outstanding at December 31, 2022 489,250 ​ $ 39.35 ​ ​ ​ ​ ​ Plus: Stock appreciation rights granted ​ ​ ​ ​ ​ ​ ​ ​ ​ Less: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock appreciation rights exercised — ​ ​ — ​ ​ ​ ​ ​ Stock appreciation rights expired — ​ ​ — ​ ​ ​ ​ ​ Stock appreciation rights forfeited 5,750 ​ ​ 39.33 ​ ​ ​ ​ ​ Stock appreciation rights outstanding at March 31, 2023 483,500 ​ 39.35 9.50 ​ $ 1,680 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock appreciation rights fully vested and exercisable at March 31, 2023 — ​ $ — ​ ​ ​ ​ ​ The fair value of the liability for payments due to stock appreciation rights holders at March 31, 2023 is approximately $712,000, as calculated using a Black-Sholes Merton model, and is included in other liabilities on the consolidated statements of condition. The expense recorded in connection with all grants under the SAR Plan totaled

Investment Securities, Equity S

Investment Securities, Equity Securities with Readily Determinable Fair Values and Other Investments	3 Months Ended
	Mar. 31, 2023
Investment Securities, Equity Securities with Readily Determinable Fair Values and Other Investments
Investment Securities, Equity Securities with Readily Determinable Fair Values and Other Investments	Note 6 — Investment Securities, Equity Securities with Readily Determinable Fair Values and Other Investments ​ We classify debt securities into one of three categories: held-to-maturity, available-for-sale, or trading. Such debt securities are reassessed for appropriate classification at each reporting date. Securities classified as “held-to-maturity” are carried at amortized cost for financial statement reporting, while securities classified as “available-for-sale” and “trading” 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 (loss) and accumulated other comprehensive income (loss) until realized, or in the case of losses, when deemed other than temporary. Available-for-sale and held-to-maturity debt securities in an unrealized loss position are 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 will be recorded as a charge to our ACL with subsequent changes in the amount of impairment, up or down, also recorded through our ACL. We have evaluated the debt securities classified as available-for-sale and held-to-maturity at March 31, 2023 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 March 31, 2023 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) ​ U.S. Treasury securities $ 49,967 $ — $ (42) $ 49,925 $ 49,925 ​ Residential mortgage-backed securities ​ ​ 5,184,217 ​ ​ 5,289 ​ ​ (542,277) ​ ​ 4,647,229 ​ ​ 4,647,229 ​ Obligations of states and political subdivisions ​ 162,947 ​ 1,485 ​ (1,768) ​ 162,664 ​ 162,664 ​ Total investment securities ​ $ 5,397,131 ​ $ 6,774 ​ $ (544,087) ​ $ 4,859,818 ​ $ 4,859,818 ​ (1) Included in the carrying value of residential mortgage-backed securities are $810,907 of mortgage-backed securities issued by Ginnie Mae and $3,836,322 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, 2022 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 ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ Estimated ​ ​ ​ ​ ​ ​ Amortized ​ unrealized ​ unrealized ​ fair ​ Carrying ​ ​ ​ cost ​ gains ​ losses ​ value ​ value (1) ​ ​ ​ (Dollars in Thousands) ​ U.S. Treasury securities ​ $ 49,752 ​ $ — $ (359) ​ $ 49,393 ​ $ 49,393 ​ Residential mortgage-backed securities ​ 4,805,735 ​ 3,145 ​ ​ (599,668) ​ 4,209,212 ​ 4,209,212 ​ Obligations of states and political subdivisions ​ 163,509 ​ 927 ​ (5,245) ​ 159,191 ​ 159,191 ​ Total investment securities ​ $ 5,018,996 ​ $ 4,072 ​ $ (605,272) ​ $ 4,417,796 ​ $ 4,417,796 ​ (1) Included in the carrying value of residential mortgage-backed securities are $681,121 of mortgage-backed securities issued by Ginnie Mae and $3,528,091 of mortgage-backed securities issued by Fannie Mae and Freddie. ​ The amortized cost and estimated fair value of investment securities at March 31, 2023, 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 $ 1,075 $ 1,075 $ 49,967 $ 49,925 ​ Due after one year through five years ​ 2,325 ​ 2,325 ​ — ​ ​ — ​ Due after five years through ten years ​ — ​ — ​ 440 ​ 440 ​ Due after ten years ​ — ​ — ​ 162,507 ​ 162,224 ​ Residential mortgage-backed securities ​ — ​ — ​ 5,184,217 ​ 4,647,229 ​ Total investment securities ​ $ 3,400 ​ $ 3,400 ​ $ 5,397,131 ​ $ 4,859,818 ​ ​ Residential mortgage-backed securities are securities primarily issued by the Federal Home Loan Mortgage Corporation (“Freddie Mac”), Federal National Mortgage Association (“Fannie Mae”), or the Government National Mortgage Association (“Ginnie Mae”). 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 early September 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. ​ The amortized cost and fair value of available-for-sale debt investment securities pledged to qualify for fiduciary powers, to secure public monies as required by law, repurchase agreements and short-term fixed borrowings was $1,428,702,000 and $1,249,080,000, respectively, at March 31, 2023. ​ Proceeds from the sale and calls of debt securities available-for-sale were $450,000 for the three months ended March 31, 2023, which included $0 and $0 of mortgage-backed securities. Gross gains of $0 and gross losses of $0 were realized on the sales and calls for the three months ended March 31, 2023. Proceeds from the sale and call of debt securities available-for-sale were of mortgage-backed securities. Gross gains of ​ Gross unrealized losses on debt investment securities and the fair value of the related securities, aggregated by investment category and length of time that individual debt securities have been in a continuous unrealized loss position at March 31, 2023, 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: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury securities ​ $ 49,925 ​ $ (42) ​ $ — ​ $ — ​ $ 49,925 ​ $ (42) ​ Residential mortgage-backed securities ​ 1,438,275 ​ (44,176) ​ 2,969,348 ​ (498,101) ​ 4,407,623 ​ (542,277) ​ Obligations of states and political subdivisions ​ 105,758 ​ (1,768) ​ — ​ — ​ 105,758 ​ (1,768) ​ ​ ​ $ 1,593,958 ​ $ (45,986) ​ $ 2,969,348 ​ $ (498,101) ​ $ 4,563,306 ​ $ (544,087) ​ ​ 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, 2022 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: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury securities ​ $ 49,394 ​ $ (359) ​ $ — ​ $ — ​ $ 49,394 ​ $ (359) Residential mortgage-backed securities ​ 1,357,905 ​ (87,815) ​ 2,566,975 ​ (511,853) ​ 3,924,880 ​ (599,668) Obligations of states and political subdivisions ​ 118,772 ​ (5,245) ​ — ​ — ​ 118,772 ​ (5,245) ​ ​ $ 1,526,071 ​ $ (93,419) ​ $ 2,566,975 ​ $ (511,853) ​ $ 4,093,046 ​ $ (605,272) ​ 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 will more than likely 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. We generally use a dollar cost averaging method of investing to manage our investment portfolio thereby averaging our investment returns over time. ​ Equity securities with readily determinable fair values consist primarily of Community Reinvestment Act funds. At March 31, 2023 and December 31, 2022, the balance in equity securities with readily determinable fair values recorded at fair value were , respectively. The following is a summary of unrealized and realized gains and losses recognized in net income on equity securities during the three months ended March 31, 2023 and the three months ended March 31, 2022: ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, 2023 ​ ​ (Dollars in Thousands) ​ ​ ​ ​ ​ ​ ​ ​ Net gains recognized during the period on equity securities $ ​ 34 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 ​ $ ​ 34 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, 2022 ​ ​ (Dollars in Thousands) ​ ​ ​ ​ ​ ​ ​ ​ Net losses recognized during the period on equity securities $ ​ (269) 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 ​ $ ​ (269) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other investments include equity and merchant banking investments held by our subsidiary banks and non-banking entities. We hold ownership interests in limited partnerships for the purpose of investing in low-income housing tax credit (“LIHTC”) projects. The partnerships may acquire, construct or rehabilitate housing for low- and moderate-income individuals. We realize a return primarily from federal tax credits and other federal tax deductions associated with the underlying projects. We are a limited partner in the partnerships, and not required to consolidate the entities in our consolidated financial statements. Investments in LIHTC projects totaled at March 31, 2023 and at December 31, 2022 and are included in other investments on the consolidated financial statements. Unfunded commitments to LIHTC projects totaled

Other Borrowed Funds

Other Borrowed Funds	3 Months Ended
	Mar. 31, 2023
Other Borrowed Funds
Other Borrowed Funds	Note 7 — Other Borrowed Funds ​ Other borrowed funds include FHLB borrowings, which are short-term and long-term borrowings issued by the FHLB of Dallas at the market price offered at the time of funding. These borrowings are secured by residential mortgage-backed investment securities and a portion of our loan portfolio. At March 31, 2023, other borrowed funds totaled

Junior Subordinated Deferrable

Junior Subordinated Deferrable Interest Debentures	3 Months Ended
	Mar. 31, 2023
Junior Subordinated Deferrable Interest Debentures
Junior Subordinated Deferrable Interest Debentures	Note 8 — Junior Subordinated Interest Deferrable Debentures ​ As of March 31, 2023, we had five statutory business trusts under the laws of the State of Delaware, for the purpose of issuing trust preferred securities. The five statutory business trusts we formed (the “Trusts”) each issued Capital and Common Securities and invested the proceeds thereof in an equivalent amount of junior subordinated debentures (“Debentures”) that we issued. As of March 31, 2023 and December 31, 2022, the principal amount of Debentures outstanding totaled $134,642,000. ​ The Debentures are subordinated and junior in right of payment to all present and future senior indebtedness (as defined in the respective Indentures) and are pari passu ​ For financial reporting purposes, the Trusts are treated as our investments and not consolidated in our consolidated financial statements. Although the Capital and Common Securities issued by each of the Trusts are not included as a component of shareholders’ equity on the consolidated statement of condition, the Capital and Common Securities are treated as capital for regulatory purposes. Specifically, under applicable regulatory guidelines, the Capital and Common Securities issued by the Trusts qualify as Tier 1 capital up to a maximum of aggregate basis. Any amount that exceeds the threshold would qualify as Tier 2 capital. At March 31, 2023 and December 31, 2022, the total $ ​ The following table illustrates key information about each of the Capital and Common Securities and their interest rate at March 31, 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 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 7.88 % LIBOR + 3.05 October 2033 October 2008 ​ Trust IX ​ 41,238 Quarterly 6.37 % LIBOR + 1.62 October 2036 October 2011 ​ Trust X ​ 21,021 Quarterly 6.46 % LIBOR + 1.65 February 2037 February 2012 ​ Trust XI ​ 25,990 Quarterly 6.37 % LIBOR + 1.62 July 2037 July 2012 ​ Trust XII ​ 20,619 Quarterly 6.41 % LIBOR + 1.45 September 2037 September 2012 ​ ​ ​ $ 134,642 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) The Capital and Common Securities may be redeemed in whole or in part on any interest payment date after the Optional Redemption Date.

Common Stock and Dividends

Common Stock and Dividends	3 Months Ended
	Mar. 31, 2023
Common Stock and Dividends
Common Stock and Dividends	Note 9 — Common Stock and Dividends ​ We paid cash dividends of $.63 per share on February 28, 2023 to record holders of our common stock on February 15, 2023. We paid cash dividends of per share on February 28, 2022 to record holders of our common Stock on February 15, 2022. ​ In April 2009, the Board of Directors re-established a formal stock repurchase program that authorized the repurchase of up to $40 million of common stock within the following 12 months . Annually since then, including on February 21, 2023, the Board of Directors extended and increased the repurchase program to purchase up to

Commitments and Contingent Liab

Commitments and Contingent Liabilities	3 Months Ended
	Mar. 31, 2023
Commitments and Contingent Liabilities
Commitments and Contingent Liabilities and Other Tax Matters	Note 10 — Commitments and Contingent Liabilities ​ We are involved in various legal proceedings that are in various stages of litigation. We have determined, based on discussions with its 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 financial position or results of operations. However, many of these matters are in various stages of proceedings and further developments could cause management to revise its assessment of these matters.

Capital Ratios

Capital Ratios	3 Months Ended
	Mar. 31, 2023
Capital Requirements
Capital Ratios	Note 11 — Capital Ratios ​ Banks and bank holding companies are subject to various regulatory capital requirements administered by state and federal banking agencies. Capital adequacy guidelines and, additionally for banks, prompt corrective action regulations, involve quantitative measures of assets, liabilities, and certain off-balance sheet items calculated under regulatory accounting practices. Capital amount and classifications are also subject to qualitative judgements by regulators about components, risk-weighting and other factors. ​ In July 2013, the Federal Deposit Insurance Corporation (“FDIC”) and other regulatory bodies established a new, comprehensive capital framework for U.S. banking organizations, consisting of minimum requirements that increase both the quantity and quality of capital held by banking organizations. The final rules are a result of the implementation of the BASEL III capital reforms and various Dodd-Frank Wall Street Reform and Consumer Protection Act (“Dodd Frank”) related capital provisions. Consistent with the Basel international framework, the rules include a minimum ratio of Common Equity Tier 1 (“CET1”) to risk-weighted assets of 4.5% and a CET1 capital conservation buffer of 2.5% of risk-weighted assets. The capital conservation buffer began phasing-in on January 1, 2016 at .625% and increased each year until January 1, 2019, when we were required to have a 2.5% capital conservation buffer, effectively resulting in a minimum ratio of CET1 capital to risk-weighted assets of at least 7% upon full implementation. The rules also raised the minimum ratio of Tier 1 capital to risk-weighted assets from 4% to 6% and include a minimum leverage ratio of 4% for all banking organizations. Regarding the quality of capital, the rules emphasize CET1 capital and implements strict eligibility criteria for regulatory capital instruments. The rules also improve the methodology for calculating risk-weighted assets to enhance risk sensitivity. The rules were subject to a four-year phase in period for mandatory compliance and we were required to begin to phase in the rules beginning on January 1, 2015. We believe that as of March 31, 2023, we continue to meet all fully phased-in capital adequacy requirements. 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. ​ We had a CET1 to risk-weighted assets ratio of 20.43% on March 31, 2023 and 20.21% on December 31, 2022. We had a Tier 1 capital-to-average-total-asset (leverage) ratio of at March 31, 2023 and December 31, 2022, respectively. Our CET1 capital consists of common stock and related surplus, net of treasury stock, and retained earnings. We and our Subsidiary Banks elected to opt-out of the requirement to include most components of accumulated other comprehensive income (loss) in the calculation of CET1 capital. CET1 is reduced by goodwill and other intangible assets, net of associated deferred tax liabilities and subject to transition provisions. Tier 1 capital includes CET1 capital and additional Tier 1 capital. Additional Tier 1 capital includes the Capital and Common Securities issued by the Trusts (see Note 8 above) up to a maximum of of Tier 1 capital on an aggregate basis. Any amount that exceeds the threshold qualifies as Tier 2 capital. As of March 31, 2023, the total of of the Capital and Common Securities outstanding qualified as Tier 1 capital. We actively monitor the regulatory capital ratios to ensure that our Subsidiary Banks are well-capitalized under the regulatory framework. ​ The CET1, Tier 1 and Total capital ratios are calculated by dividing the respective capital amounts by risk-weighted assets. Risk-weighted assets are calculated based on regulatory requirements and include total assets, excluding goodwill and other intangible assets, allocated by risk-weight category, and certain off-balance-sheet items, among other things. The leverage ratio is calculated by dividing Tier 1 capital by adjusted quarterly average total assets, which exclude goodwill and other intangible assets, among other things. ​ We and our Subsidiary Banks are subject to the regulatory capital requirements administered by the Federal Reserve, and, for our Subsidiary Banks, the FDIC. Regulatory authorities can initiate certain mandatory actions if we or any of our Subsidiary Banks fail to meet the minimum capital requirements, which could have a direct material effect on our financial statements. Management believes, as of March 31, 2023, that we and each of our Subsidiary Banks meet all capital adequacy requirements to which we are subject.

Fair Value (Tables)

Fair Value (Tables)	3 Months Ended
	Mar. 31, 2023
Fair Value
Assets and liabilities measured at fair value on a recurring basis	The following table represents assets and liabilities reported on the consolidated balance sheets at their fair value on a recurring basis as of March 31, 2023 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 ​ ​ ​ March 31, 2023 ​ (Level 1) ​ (Level 2) ​ (Level 3) ​ Measured on a recurring basis: ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Available for sale debt securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury securities ​ $ 49,925 ​ $ — ​ $ 49,925 ​ $ — ​ Residential mortgage-backed securities ​ ​ 4,647,229 ​ ​ — ​ ​ 4,647,229 ​ ​ — ​ States and political subdivisions ​ 162,664 ​ — ​ 162,664 ​ — ​ Equity Securities ​ 5,392 ​ 5,392 ​ — ​ — ​ ​ ​ $ 4,865,210 ​ $ 5,392 ​ $ 4,859,818 ​ $ — ​ ​ The following table represents assets and liabilities reported on the consolidated balance sheets at their fair value on a recurring basis as of December 31, 2022 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, 2022 ​ (Level 1) ​ (Level 2) ​ (Level 3) ​ Measured on a recurring basis: ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Available for sale securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury securities ​ $ 49,393 ​ $ — ​ $ 49,393 ​ $ — ​ Residential mortgage-backed securities ​ ​ 4,209,212 ​ ​ — ​ ​ 4,209,212 ​ ​ — ​ States and political subdivisions ​ 159,191 ​ — ​ 159,191 ​ — ​ Equity Securities ​ 5,358 ​ 5,358 ​ — ​ — ​ ​ ​ $ 4,423,154 ​ $ 5,358 ​ $ 4,417,796 ​ $ — ​ ​
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 March 31, 2023 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 ​ ​ Period ended ​ Identical ​ Observable ​ Unobservable ​ Provision ​ ​ March 31, ​ Assets ​ Inputs ​ Inputs ​ During ​ ​ 2023 ​ (Level 1) ​ (Level 2) ​ (Level 3) ​ Period Measured on a non-recurring basis: ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Watch-List doubtful loans ​ $ 29,894 ​ $ — ​ $ — ​ $ 29,894 ​ $ 1,000 Other real estate owned ​ ​ 752 ​ ​ — ​ ​ — ​ ​ 752 ​ ​ 250 ​ The following table represents financial instruments measured at fair value on a non-recurring basis as of and for the period ended December 31, 2022 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 ​ ​ Year ended ​ for Identical ​ Observable ​ Unobservable ​ Provision ​ ​ December 31, ​ Assets ​ Inputs ​ Inputs ​ During ​ ​ 2022 ​ (Level 1) ​ (Level 2) ​ (Level 3) ​ Period Measured on a non-recurring basis: ​ ​ ​ ​ ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Watch-List doubtful loans ​ $ 30,743 ​ $ — ​ $ — ​ $ 30,743 ​ $ 2,346 Other real estate owned ​ 5,653 ​ — ​ — ​ 5,653 ​ 1,627 ​

Loans (Tables)

Loans (Tables)	3 Months Ended
	Mar. 31, 2023
Loans
Summary of loans, by loan type	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ ​ ​ 2023 ​ 2022 ​ ​ ​ (Dollars in Thousands) ​ Commercial, financial and agricultural $ 4,370,745 $ 4,373,373 ​ Real estate - mortgage ​ 858,909 ​ 865,994 ​ Real estate - construction ​ 2,081,138 ​ 1,989,669 ​ Consumer ​ 43,390 ​ 41,592 ​ Foreign ​ 177,591 ​ 159,975 ​ Total loans ​ $ 7,531,773 ​ $ 7,430,603 ​

Allowance for Credit Losses (Ta

Allowance for Credit Losses (Tables)	3 Months Ended
	Mar. 31, 2023
Allowance for Credit Losses
Loans individually or collectively evaluated for their impairment and related allowance, by loan class	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2023 ​ ​ ​ ​ ​ ​ 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, 2022 ​ $ 26,728 ​ $ 44,684 ​ $ 36,474 ​ $ 3,794 ​ $ 4,759 ​ $ 8,284 ​ $ 281 ​ $ 968 ​ $ 125,972 ​ Losses charged to allowance ​ (1,971) ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ (1) ​ ​ (61) ​ ​ — ​ (2,033) ​ Recoveries credited to allowance ​ 625 ​ ​ 311 ​ ​ 5 ​ ​ — ​ ​ 7 ​ ​ 77 ​ ​ 6 ​ ​ — ​ 1,031 ​ Net (losses) recoveries charged to allowance ​ (1,346) ​ 311 ​ 5 ​ — ​ 7 ​ 76 ​ (55) ​ — ​ (1,002) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Credit loss expense ​ 2,406 ​ ​ 5,938 ​ ​ 77 ​ ​ 190 ​ ​ (207) ​ ​ (3) ​ ​ 65 ​ ​ 121 ​ 8,587 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at March 31, 2023 ​ $ 27,788 ​ $ 50,933 ​ $ 36,556 ​ $ 3,984 ​ $ 4,559 ​ $ 8,357 ​ $ 291 ​ $ 1,089 ​ $ 133,557 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, 2022 ​ ​ ​ ​ ​ ​ 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, 2021 ​ $ 23,178 ​ $ 35,390 ​ $ 35,654 ​ $ 3,291 ​ $ 4,073 ​ $ 7,754 ​ $ 272 ​ $ 762 ​ $ 110,374 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Losses charged to allowance ​ (2,112) ​ ​ (2) ​ ​ — ​ ​ — ​ ​ (99) ​ ​ (28) ​ ​ (88) ​ ​ — ​ (2,329) ​ Recoveries credited to allowance ​ 602 ​ ​ 2 ​ ​ 8 ​ ​ — ​ ​ 30 ​ ​ 48 ​ ​ 11 ​ ​ — ​ 701 ​ Net (losses) recoveries charged to allowance ​ (1,510) ​ — ​ 8 ​ — ​ (69) ​ 20 ​ (77) ​ — ​ (1,628) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Credit loss expense ​ 2,233 ​ ​ 982 ​ ​ (808) ​ ​ (229) ​ ​ 12 ​ ​ (728) ​ ​ 69 ​ ​ (50) ​ 1,481 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at March 31, 2022 ​ $ 23,901 ​ $ 36,372 ​ $ 34,854 ​ $ 3,062 ​ $ 4,016 ​ $ 7,046 ​ $ 264 ​ $ 712 ​ $ 110,227 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2023 ​ ​ ​ Loans Individually ​ Loans Collectively ​ ​ ​ Evaluated For ​ Evaluated For ​ ​ ​ Impairment ​ Impairment ​ ​ ​ Recorded ​ ​ ​ ​ Recorded ​ ​ ​ ​ ​ ​ Investment ​ Allowance ​ Investment ​ Allowance ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial $ 30,529 $ 3,375 $ 1,467,573 $ 24,413 ​ Commercial real estate: other construction & land development ​ 20,481 ​ 70 ​ 2,060,657 ​ 50,863 ​ Commercial real estate: farmland & commercial ​ 297 ​ — ​ 2,562,801 ​ 36,556 ​ Commercial real estate: multifamily ​ 110 ​ — ​ 309,435 ​ 3,984 ​ Residential: first lien ​ 74 ​ — ​ 419,481 ​ 4,559 ​ Residential: junior lien ​ 318 ​ — ​ 439,036 ​ 8,357 ​ Consumer ​ — ​ — ​ 43,390 ​ 291 ​ Foreign ​ — ​ — ​ 177,591 ​ 1,089 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 51,809 ​ $ 3,445 ​ $ 7,479,964 ​ $ 130,112 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ ​ ​ Loans Individually ​ Loans Collectively ​ ​ ​ Evaluated For ​ Evaluated For ​ ​ ​ Impairment ​ Impairment ​ ​ ​ Recorded ​ ​ ​ ​ Recorded ​ ​ ​ ​ ​ ​ Investment ​ Allowance ​ Investment ​ Allowance ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial $ 30,747 $ 2,375 $ 1,468,006 $ 24,353 ​ Commercial real estate: other construction & land development ​ 20,483 ​ 70 ​ 1,969,186 ​ 44,614 ​ Commercial real estate: farmland & commercial ​ 94 ​ — ​ 2,568,025 ​ 36,474 ​ Commercial real estate: multifamily ​ 117 ​ — ​ 306,384 ​ 3,794 ​ Residential: first lien ​ 77 ​ — ​ 425,647 ​ 4,759 ​ Residential: junior lien ​ 312 ​ — ​ 439,958 ​ 8,284 ​ Consumer ​ — ​ — ​ 41,592 ​ 281 ​ Foreign ​ — ​ — ​ 159,975 ​ 968 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 51,830 ​ $ 2,445 ​ $ 7,378,773 ​ $ 123,527 ​ ​
Loans accounted on non-accrual basis, by loan class	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2023 ​ December 31, 2022 ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ ​ ​ ​ Commercial $ 30,529 $ 30,747 ​ Commercial real estate: other construction & land development ​ 20,481 ​ 20,483 ​ Commercial real estate: farmland & commercial ​ 297 ​ 94 ​ Commercial real estate: multifamily ​ 110 ​ 117 ​ Residential: first lien ​ 215 ​ 207 ​ Total non-accrual loans ​ $ 51,632 ​ $ 51,648 ​ ​
Loans accounted for as trouble debt restructuring, by loan class	​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ ​ ​ (Dollars in Thousands) ​ Domestic ​ ​ ​ ​ Residential: first lien ​ $ 1,642 ​ Residential: junior lien ​ ​ 714 ​ Consumer ​ ​ 802 ​ Foreign ​ ​ 55 ​ Total troubled debt restructuring ​ $ 3,213 ​
Information regarding the aging of past due loans, by loan class	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 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 $ 2,162 $ 217 $ 30,549 $ 121 $ 32,928 $ 1,465,174 $ 1,498,102 ​ Commercial real estate: other construction & land development ​ 14,242 ​ — ​ 19,982 ​ — ​ 34,224 ​ 2,046,914 ​ 2,081,138 ​ Commercial real estate: farmland & commercial ​ 594 ​ 4,565 ​ — ​ — ​ 5,159 ​ 2,557,940 ​ 2,563,099 ​ Commercial real estate: multifamily ​ 233 ​ — ​ — ​ — ​ 233 ​ 309,311 ​ 309,544 ​ Residential: first lien ​ 1,189 ​ 1,153 ​ 3,097 ​ 2,864 ​ 5,439 ​ 414,116 ​ 419,555 ​ Residential: junior lien ​ 1,235 ​ 258 ​ 2,051 ​ 2,051 ​ 3,544 ​ 435,810 ​ 439,354 ​ Consumer ​ 270 ​ 30 ​ 12 ​ 12 ​ 312 ​ 43,078 ​ 43,390 ​ Foreign ​ 598 ​ 11 ​ 581 ​ 581 ​ 1,190 ​ 176,401 ​ 177,591 ​ Total past due loans ​ $ 20,523 ​ $ 6,234 ​ $ 56,272 ​ $ 5,629 ​ $ 83,029 ​ $ 7,448,744 ​ $ 7,531,773 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 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 ​ $ 1,732 $ 258 $ 1,014 $ 59 $ 3,004 $ 1,495,750 $ 1,498,754 ​ Commercial real estate: other construction & land development ​ 1,130 ​ — ​ — ​ — ​ 1,130 ​ 1,988,539 ​ 1,989,669 ​ Commercial real estate: farmland & commercial ​ 1,744 ​ 117 ​ — ​ — ​ 1,861 ​ 2,566,257 ​ 2,568,118 ​ Commercial real estate: multifamily ​ — ​ — ​ — ​ — ​ — ​ 306,501 ​ 306,501 ​ Residential: first lien ​ 2,023 ​ 1,068 ​ 4,189 ​ 4,061 ​ 7,280 ​ 418,444 ​ 425,724 ​ Residential: junior lien ​ 925 ​ 771 ​ 1,717 ​ 1,717 ​ 3,413 ​ 436,857 ​ 440,270 ​ Consumer ​ 281 ​ 14 ​ 7 ​ 7 ​ 302 ​ 41,290 ​ 41,592 ​ Foreign ​ 717 ​ 23 ​ 288 ​ 288 ​ 1,028 ​ 158,947 ​ 159,975 ​ Total past due loans ​ $ 8,552 ​ $ 2,251 ​ $ 7,215 ​ $ 6,132 ​ $ 18,018 ​ $ 7,412,585 ​ $ 7,430,603 ​ ​
Summary of the loan portfolio by credit quality indicator, by loan class	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2023 2022 2021 2020 2019 Prior Total ​ ​ ​ (Dollars in Thousands) ​ Balance at March 31, 2023 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 263,913 ​ $ 530,585 ​ $ 452,955 ​ $ 87,039 ​ $ 32,481 ​ $ 68,318 ​ $ 1,435,291 ​ Special Review ​ ​ — ​ ​ 371 ​ ​ 201 ​ ​ — ​ ​ — ​ ​ — ​ ​ 572 ​ Watch List - Substandard ​ ​ 218 ​ ​ 28,889 ​ ​ 130 ​ ​ — ​ ​ 19 ​ ​ 2,454 ​ ​ 31,710 ​ Watch List - Doubtful ​ ​ — ​ ​ 29,789 ​ ​ — ​ ​ 739 ​ ​ — ​ ​ 1 ​ ​ 30,529 ​ Total Commercial ​ $ 264,131 ​ $ 589,634 ​ $ 453,286 ​ $ 87,778 ​ $ 32,500 ​ $ 70,773 ​ $ 1,498,102 ​ Commercial real estate: other construction & land development ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 341,573 ​ $ 840,168 ​ $ 530,211 ​ $ 186,626 ​ $ 124,467 ​ $ 37,404 ​ $ 2,060,449 ​ Special Review ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 208 ​ ​ — ​ ​ 208 ​ Watch List - Doubtful ​ ​ — ​ ​ 19,982 ​ ​ 407 ​ ​ 92 ​ ​ — ​ ​ — ​ ​ 20,481 ​ Total Commercial real estate: other construction & land development ​ $ 341,573 ​ $ 860,150 ​ $ 530,618 ​ $ 186,718 ​ $ 124,675 ​ $ 37,404 ​ $ 2,081,138 ​ Commercial real estate: farmland & commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 294,941 ​ $ 723,848 ​ $ 534,498 ​ $ 353,714 ​ $ 228,974 ​ $ 336,205 ​ $ 2,472,180 ​ Special Review ​ ​ — ​ ​ 173 ​ ​ — ​ ​ 835 ​ ​ — ​ ​ — ​ ​ 1,008 ​ Watch List - Pass ​ ​ — ​ ​ 16,986 ​ ​ 243 ​ ​ — ​ ​ — ​ ​ — ​ ​ 17,229 ​ Watch List - Substandard ​ ​ — ​ ​ 54,038 ​ ​ 4,556 ​ ​ 2,486 ​ ​ 93 ​ ​ 11,212 ​ ​ 72,385 ​ Watch List - Doubtful ​ ​ — ​ ​ 91 ​ ​ — ​ ​ — ​ ​ — ​ ​ 206 ​ ​ 297 ​ Total Commercial real estate: farmland & commercial ​ $ 294,941 ​ $ 795,136 ​ $ 539,297 ​ $ 357,035 ​ $ 229,067 ​ $ 347,623 ​ $ 2,563,099 ​ Commercial real estate: multifamily ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 45,117 ​ $ 125,030 ​ $ 50,142 ​ $ 58,802 ​ $ 11,427 ​ $ 18,916 ​ $ 309,434 ​ Watch List - Doubtful ​ ​ — ​ ​ 110 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 110 ​ Total Commercial real estate: multifamily ​ $ 45,117 ​ $ 125,140 ​ $ 50,142 ​ $ 58,802 ​ $ 11,427 ​ $ 18,916 ​ $ 309,544 ​ Residential: first lien ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 71,028 ​ $ 97,907 ​ $ 76,400 ​ $ 45,354 ​ $ 32,016 ​ $ 96,356 ​ $ 419,061 ​ Watch List - Substandard ​ ​ — ​ ​ — ​ ​ 354 ​ ​ 66 ​ ​ — ​ ​ — ​ ​ 420 ​ Watch List - Doubtful ​ ​ — ​ ​ 74 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 74 ​ Total Residential: first lien ​ $ 71,028 ​ $ 97,981 ​ $ 76,754 ​ $ 45,420 ​ $ 32,016 ​ $ 96,356 ​ $ 419,555 ​ Residential: junior lien ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 15,944 ​ $ 90,944 ​ $ 103,512 ​ $ 86,758 ​ $ 39,295 ​ $ 102,583 ​ $ 439,036 ​ Watch List- Doubtful ​ ​ — ​ ​ 318 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 318 ​ Total Residential: junior lien ​ $ 15,944 ​ $ 91,262 ​ $ 103,512 ​ $ 86,758 ​ $ 39,295 ​ $ 102,583 ​ $ 439,354 ​ Residential: junior lien ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consumer ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 12,176 ​ $ 24,278 ​ $ 4,412 ​ $ 542 ​ $ 344 ​ $ 1,638 ​ $ 43,390 ​ Total Consumer ​ $ 12,176 ​ $ 24,278 ​ $ 4,412 ​ $ 542 ​ $ 344 ​ $ 1,638 ​ $ 43,390 ​ Foreign ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 27,135 ​ $ 119,493 ​ $ 15,902 ​ $ 4,996 ​ $ 4,479 ​ $ 5,586 ​ $ 177,591 ​ Total Foreign ​ $ 27,135 ​ $ 119,493 ​ $ 15,902 ​ $ 4,996 ​ $ 4,479 ​ $ 5,586 ​ $ 177,591 ​ Total Loans ​ $ 1,072,045 ​ $ 2,703,074 ​ $ 1,773,923 ​ $ 828,049 ​ $ 473,803 ​ $ 680,879 ​ $ 7,531,773 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 2021 2020 2019 2018 Prior Total ​ ​ (Dollars in Thousands) Balance at December 31, 2022 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Domestic ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 736,462 ​ $ 524,879 ​ $ 96,401 ​ $ 35,917 ​ $ 43,792 ​ $ 29,464 ​ $ 1,466,915 Special Review ​ ​ 377 ​ ​ 213 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 590 Watch List - Substandard ​ ​ 161 ​ ​ 149 ​ ​ 143 ​ ​ — ​ ​ 49 ​ ​ — ​ ​ 502 Watch List - Doubtful ​ ​ 29,789 ​ ​ — ​ ​ 954 ​ ​ — ​ ​ — ​ ​ 4 ​ ​ 30,747 Total Commercial ​ $ 766,789 ​ $ 525,241 ​ $ 97,498 ​ $ 35,917 ​ $ 43,841 ​ $ 29,468 ​ $ 1,498,754 Commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial real estate: other construction & land development ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 913,675 ​ $ 666,347 ​ $ 173,824 ​ $ 174,897 ​ $ 35,069 ​ $ 5,165 ​ $ 1,968,977 Special Review ​ ​ — ​ ​ — ​ ​ — ​ ​ 209 ​ ​ — ​ ​ — ​ ​ 209 Watch List - Doubtful ​ ​ 19,982 ​ ​ 407 ​ ​ 94 ​ ​ — ​ ​ — ​ ​ — ​ ​ 20,483 Total Commercial real estate: other construction & land development ​ $ 933,657 ​ $ 666,754 ​ $ 173,918 ​ $ 175,106 ​ $ 35,069 ​ $ 5,165 ​ $ 1,989,669 Commercial real estate: farmland & commercial ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 811,117 ​ $ 584,134 ​ $ 456,200 ​ $ 232,537 ​ $ 325,214 ​ $ 81,295 ​ $ 2,490,497 Special Review ​ ​ 2,855 ​ ​ — ​ ​ 842 ​ ​ — ​ ​ — ​ ​ — ​ ​ 3,697 Watch List - Pass ​ ​ 17,060 ​ ​ 247 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 17,307 Watch List - Substandard ​ ​ 2,275 ​ ​ — ​ ​ 54,152 ​ ​ 96 ​ ​ — ​ ​ — ​ ​ 56,523 Watch List - Doubtful ​ ​ 94 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 94 Total Commercial real estate: farmland & commercial ​ $ 833,401 ​ $ 584,381 ​ $ 511,194 ​ $ 232,633 ​ $ 325,214 ​ $ 81,295 ​ $ 2,568,118 Commercial real estate: multifamily ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 127,680 ​ $ 87,469 ​ $ 59,035 ​ $ 12,026 ​ $ 5,490 ​ $ 14,684 ​ $ 306,384 Watch List - Doubtful ​ ​ 117 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 117 Total Commercial real estate: multifamily ​ $ 127,797 ​ $ 87,469 ​ $ 59,035 ​ $ 12,026 ​ $ 5,490 ​ $ 14,684 ​ $ 306,501 Residential: first lien ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 138,771 ​ $ 82,466 ​ $ 49,591 ​ $ 40,985 ​ $ 33,814 ​ $ 79,660 ​ $ 425,287 Watch List - Substandard ​ ​ — ​ ​ 360 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 360 Watch List - Doubtful ​ ​ 77 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 77 Total Residential: first lien ​ $ 138,848 ​ $ 82,826 ​ $ 49,591 ​ $ 40,985 ​ $ 33,814 ​ $ 79,660 ​ $ 425,724 Residential: junior lien ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 92,256 ​ $ 108,815 ​ $ 91,130 ​ $ 41,273 ​ $ 21,975 ​ $ 84,509 ​ $ 439,958 Watch List- Doubtful ​ ​ — ​ ​ 312 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 312 Total Residential: junior lien ​ $ 92,256 ​ $ 109,127 ​ $ 91,130 ​ $ 41,273 ​ $ 21,975 ​ $ 84,509 ​ $ 440,270 Consumer ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 31,962 ​ $ 6,603 ​ $ 897 ​ $ 489 ​ $ 28 ​ $ 1,613 ​ $ 41,592 Total Consumer ​ $ 31,962 ​ $ 6,603 ​ $ 897 ​ $ 489 ​ $ 28 ​ $ 1,613 ​ $ 41,592 Foreign ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pass ​ $ 124,265 ​ $ 19,082 ​ $ 5,362 ​ $ 4,848 ​ $ 3,417 ​ $ 3,001 ​ $ 159,975 Total Foreign ​ $ 124,265 ​ $ 19,082 ​ $ 5,362 ​ $ 4,848 ​ $ 3,417 ​ $ 3,001 ​ $ 159,975 Total Loans ​ $ 3,048,975 ​ $ 2,081,483 ​ $ 988,625 ​ $ 543,277 ​ $ 468,848 ​ $ 299,395 ​ $ 7,430,603

Stock Options and Stock Appre_2

Stock Options and Stock Appreciation Rights (Tables)	3 Months Ended
	Mar. 31, 2023
Stock Options and Stock Appreciation Rights
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, 2022 461,822 ​ $ 29.67 ​ ​ ​ ​ ​ ​ Plus: Options granted — ​ — ​ ​ ​ ​ ​ ​ Less: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options exercised 3,537 ​ 24.00 ​ ​ ​ ​ ​ ​ Options expired — ​ — ​ ​ ​ ​ ​ ​ Options forfeited 2,938 ​ 36.51 ​ ​ ​ ​ ​ ​ Options outstanding at March 31, 2023 455,347 ​ 29.67 3.82 ​ $ 5,987 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Options fully vested and exercisable at March 31, 2023 257,932 ​ $ 25.20 2.06 ​ $ 4,545 ​ ​
Summary of activity under the SAR Plan	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ Weighted ​ average ​ ​ ​ ​ ​ Number of ​ average ​ remaining ​ Aggregate ​ ​ stock appreciation ​ exercise ​ contractual ​ intrinsic ​ ​ rights ​ price ​ term (years) ​ value ($) ​ ​ ​ ​ ​ ​ ​ ​ ​ (in Thousands) Stock appreciation rights outstanding at December 31, 2022 489,250 ​ $ 39.35 ​ ​ ​ ​ ​ Plus: Stock appreciation rights granted ​ ​ ​ ​ ​ ​ ​ ​ ​ Less: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock appreciation rights exercised — ​ ​ — ​ ​ ​ ​ ​ Stock appreciation rights expired — ​ ​ — ​ ​ ​ ​ ​ Stock appreciation rights forfeited 5,750 ​ ​ 39.33 ​ ​ ​ ​ ​ Stock appreciation rights outstanding at March 31, 2023 483,500 ​ 39.35 9.50 ​ $ 1,680 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock appreciation rights fully vested and exercisable at March 31, 2023 — ​ $ — ​ ​ ​ ​ ​

Investment Securities, Equity_2

Investment Securities, Equity Securities with Readily Determinable Fair Values and Other Investments (Tables)	3 Months Ended
	Mar. 31, 2023
Investment Securities, Equity Securities with Readily Determinable Fair Values and Other Investments
Amortized cost and estimated fair value by type of investment security	The amortized cost and estimated fair value by type of investment security at March 31, 2023 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) ​ U.S. Treasury securities $ 49,967 $ — $ (42) $ 49,925 $ 49,925 ​ Residential mortgage-backed securities ​ ​ 5,184,217 ​ ​ 5,289 ​ ​ (542,277) ​ ​ 4,647,229 ​ ​ 4,647,229 ​ Obligations of states and political subdivisions ​ 162,947 ​ 1,485 ​ (1,768) ​ 162,664 ​ 162,664 ​ Total investment securities ​ $ 5,397,131 ​ $ 6,774 ​ $ (544,087) ​ $ 4,859,818 ​ $ 4,859,818 ​ (1) Included in the carrying value of residential mortgage-backed securities are $810,907 of mortgage-backed securities issued by Ginnie Mae and $3,836,322 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, 2022 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 ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ Estimated ​ ​ ​ ​ ​ ​ Amortized ​ unrealized ​ unrealized ​ fair ​ Carrying ​ ​ ​ cost ​ gains ​ losses ​ value ​ value (1) ​ ​ ​ (Dollars in Thousands) ​ U.S. Treasury securities ​ $ 49,752 ​ $ — $ (359) ​ $ 49,393 ​ $ 49,393 ​ Residential mortgage-backed securities ​ 4,805,735 ​ 3,145 ​ ​ (599,668) ​ 4,209,212 ​ 4,209,212 ​ Obligations of states and political subdivisions ​ 163,509 ​ 927 ​ (5,245) ​ 159,191 ​ 159,191 ​ Total investment securities ​ $ 5,018,996 ​ $ 4,072 ​ $ (605,272) ​ $ 4,417,796 ​ $ 4,417,796 ​ (1) Included in the carrying value of residential mortgage-backed securities are $681,121 of mortgage-backed securities issued by Ginnie Mae and $3,528,091 of mortgage-backed securities issued by Fannie Mae and Freddie. ​
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 $ 1,075 $ 1,075 $ 49,967 $ 49,925 ​ Due after one year through five years ​ 2,325 ​ 2,325 ​ — ​ ​ — ​ Due after five years through ten years ​ — ​ — ​ 440 ​ 440 ​ Due after ten years ​ — ​ — ​ 162,507 ​ 162,224 ​ Residential mortgage-backed securities ​ — ​ — ​ 5,184,217 ​ 4,647,229 ​ Total investment securities ​ $ 3,400 ​ $ 3,400 ​ $ 5,397,131 ​ $ 4,859,818 ​ ​
Gross unrealized losses on investment securities and the related fair value	​ Gross unrealized losses on debt investment securities and the fair value of the related securities, aggregated by investment category and length of time that individual debt securities have been in a continuous unrealized loss position at March 31, 2023, 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: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury securities ​ $ 49,925 ​ $ (42) ​ $ — ​ $ — ​ $ 49,925 ​ $ (42) ​ Residential mortgage-backed securities ​ 1,438,275 ​ (44,176) ​ 2,969,348 ​ (498,101) ​ 4,407,623 ​ (542,277) ​ Obligations of states and political subdivisions ​ 105,758 ​ (1,768) ​ — ​ — ​ 105,758 ​ (1,768) ​ ​ ​ $ 1,593,958 ​ $ (45,986) ​ $ 2,969,348 ​ $ (498,101) ​ $ 4,563,306 ​ $ (544,087) ​ ​ 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, 2022 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: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasury securities ​ $ 49,394 ​ $ (359) ​ $ — ​ $ — ​ $ 49,394 ​ $ (359) Residential mortgage-backed securities ​ 1,357,905 ​ (87,815) ​ 2,566,975 ​ (511,853) ​ 3,924,880 ​ (599,668) Obligations of states and political subdivisions ​ 118,772 ​ (5,245) ​ — ​ — ​ 118,772 ​ (5,245) ​ ​ $ 1,526,071 ​ $ (93,419) ​ $ 2,566,975 ​ $ (511,853) ​ $ 4,093,046 ​ $ (605,272) ​
Summary of unrealized and realized gains and losses recognized in net income on equity securities	​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, 2023 ​ ​ (Dollars in Thousands) ​ ​ ​ ​ ​ ​ ​ ​ Net gains recognized during the period on equity securities $ ​ 34 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 ​ $ ​ 34 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ March 31, 2022 ​ ​ (Dollars in Thousands) ​ ​ ​ ​ ​ ​ ​ ​ Net losses recognized during the period on equity securities $ ​ (269) 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 ​ $ ​ (269) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Junior Subordinated Deferrabl_2

Junior Subordinated Deferrable Interest Debentures (Tables)	3 Months Ended
	Mar. 31, 2023
Junior Subordinated Deferrable Interest Debentures
Junior subordinated interest deferrable debentures, major types of business trusts	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 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 7.88 % LIBOR + 3.05 October 2033 October 2008 ​ Trust IX ​ 41,238 Quarterly 6.37 % LIBOR + 1.62 October 2036 October 2011 ​ Trust X ​ 21,021 Quarterly 6.46 % LIBOR + 1.65 February 2037 February 2012 ​ Trust XI ​ 25,990 Quarterly 6.37 % LIBOR + 1.62 July 2037 July 2012 ​ Trust XII ​ 20,619 Quarterly 6.41 % LIBOR + 1.45 September 2037 September 2012 ​ ​ ​ $ 134,642 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) The Capital and Common Securities may be redeemed in whole or in part on any interest payment date after the Optional Redemption Date.

Basis of Presentation (Details)

Basis of Presentation (Details)	3 Months Ended
	Mar. 31, 2023 segment subsidiary
Basis of Presentation
Number of operating segments | segment	1
Number of active operating bank subsidiaries | subsidiary	5

Fair Value (Fair Value By Level

Fair Value (Fair Value By Level) (Details) - USD ($)	Mar. 31, 2023	Dec. 31, 2022
Assets:
Available for sale debt securities	$ 4,859,818,000	$ 4,417,796,000
Equity Securities	5,392,000	5,358,000
Estimate of Fair Value Measurement | US Treasury Securities
Assets:
Available for sale debt securities	49,925,000	49,393,000
Estimate of Fair Value Measurement | Residential mortgage-backed securities
Assets:
Available for sale debt securities	4,647,229,000	4,209,212,000
Estimate of Fair Value Measurement | States and political subdivisions
Assets:
Available for sale debt securities	162,664,000	159,191,000
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement
Assets:
Equity Securities	5,392,000	5,358,000
Marketable Securities	4,865,210,000	4,423,154,000
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement | US Treasury Securities
Assets:
Available for sale debt securities	49,925,000	49,393,000
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement | Residential mortgage-backed securities
Assets:
Available for sale debt securities	4,647,229,000	4,209,212,000
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement | States and political subdivisions
Assets:
Available for sale debt securities	162,664,000	159,191,000
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement | Fair Value, Inputs, Level 1
Assets:
Equity Securities	5,392,000	5,358,000
Marketable Securities	5,392,000	5,358,000
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement | Fair Value, Inputs, Level 2
Assets:
Marketable Securities	4,859,818,000	4,417,796,000
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement | Fair Value, Inputs, Level 2 | US Treasury Securities
Assets:
Available for sale debt securities	49,925,000	49,393,000
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement | Fair Value, Inputs, Level 2 | Residential mortgage-backed securities
Assets:
Available for sale debt securities	4,647,229,000	4,209,212,000
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement | Fair Value, Inputs, Level 2 | States and political subdivisions
Assets:
Available for sale debt securities	$ 162,664,000	$ 159,191,000

Fair Value (Fair Value Measurem

Fair Value (Fair Value Measurement and Assumptions) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Assumptions used in discounted cash flow model to determine fair value of investments classified within level 3
Doubtful and Impaired commercial collateral dependent loans	$ 51,306,000	$ 51,326,000
Impaired commercial collateral dependent receivables appraisals to determine fair value within immediately preceding twelve months	0	0
Impaired collateral dependent commercial loans with internal evaluation completed within last twelve months	51,306,000	51,326,000
Charges to allowance for probable loan losses in connection with other real estate owned	0	2,000
Adjustment to fair value in connection with other real estate owned	250,000	1,627,000
Fair Value, Measurements, Nonrecurring
Assumptions used in discounted cash flow model to determine fair value of investments classified within level 3
Change in net provision, impaired loans	1,000,000	2,346,000
Change in net provision, other real estate owned	250,000	1,627,000
Fair Value, Measurements, Nonrecurring | Fair Value, Inputs, Level 3
Assets:
Watch-List doubtful loans	29,894,000	30,743,000
Non-financial assets:
Other real estate owned	752,000	5,653,000
Fair Value, Measurements, Nonrecurring | Estimated Fair Value
Assets:
Watch-List doubtful loans	29,894,000	30,743,000
Non-financial assets:
Other real estate owned	$ 752,000	$ 5,653,000

Fair Value (Other Assumptions)

Fair Value (Other Assumptions) (Details) - USD ($)	Mar. 31, 2023	Dec. 31, 2022
Deposits
Carrying amount of time deposits	$ 2,144,395,000	$ 2,068,184,000
Fair Value, Inputs, Level 3
Loans
Carrying amount of fixed rate performing loans	1,196,549,000	1,203,381,000
Estimated fair value of fixed rate performing loans	1,094,152,000	1,100,848,000
Deposits
Carrying amount of time deposits	2,144,695,000	2,068,184,000
Estimated fair value of time deposits	2,154,962,000	2,076,231,000
Fair Value, Inputs, Level 2
Other borrowed funds
Carrying amount of the long-term FHLB borrowings	10,895,000	10,944,000
Estimated fair value of long-term FHLB borrowings	$ 10,895,000	$ 10,944,000

Loans (Details)

Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Summary of loans, by loan type
Total loans	$ 7,531,773	$ 7,430,603
Commercial, financial and agricultural
Summary of loans, by loan type
Total loans	4,370,745	4,373,373
Real estate - mortgage
Summary of loans, by loan type
Total loans	858,909	865,994
Obligations of states and political subdivisions
Summary of loans, by loan type
Total loans	2,081,138	1,989,669
Consumer
Summary of loans, by loan type
Total loans	43,390	41,592
Foreign.
Summary of loans, by loan type
Total loans	$ 177,591	$ 159,975

Allowance for Credit Losses (By

Allowance for Credit Losses (By Loan Class) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at the beginning of the period	$ 125,972	$ 110,374
Losses charged to allowance	(2,033)	(2,329)
Recoveries credited to allowance	1,031	701
Net (losses) recoveries charged to allowance	(1,002)	(1,628)
Credit loss expense	8,587	1,481
Balance at the end of the period	133,557	110,227
Commercial, financial and agricultural | Domestic | Commercial.
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at the beginning of the period	26,728	23,178
Losses charged to allowance	(1,971)	(2,112)
Recoveries credited to allowance	625	602
Net (losses) recoveries charged to allowance	(1,346)	(1,510)
Credit loss expense	2,406	2,233
Balance at the end of the period	27,788	23,901
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at the beginning of the period	36,474	35,654
Recoveries credited to allowance	5	8
Net (losses) recoveries charged to allowance	5	8
Credit loss expense	77	(808)
Balance at the end of the period	36,556	34,854
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at the beginning of the period	3,794	3,291
Credit loss expense	190	(229)
Balance at the end of the period	3,984	3,062
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at the beginning of the period	44,684	35,390
Losses charged to allowance		(2)
Recoveries credited to allowance	311	2
Net (losses) recoveries charged to allowance	311
Credit loss expense	5,938	982
Balance at the end of the period	50,933	36,372
Real estate - mortgage | Domestic | Residential: first lien
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at the beginning of the period	4,759	4,073
Losses charged to allowance		(99)
Recoveries credited to allowance	7	30
Net (losses) recoveries charged to allowance	7	(69)
Credit loss expense	(207)	12
Balance at the end of the period	4,559	4,016
Real estate - mortgage | Domestic | Residential Junior Lien
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at the beginning of the period	8,284	7,754
Losses charged to allowance	(1)	(28)
Recoveries credited to allowance	77	48
Net (losses) recoveries charged to allowance	76	20
Credit loss expense	(3)	(728)
Balance at the end of the period	8,357	7,046
Consumer | Domestic
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at the beginning of the period	281	272
Losses charged to allowance	(61)	(88)
Recoveries credited to allowance	6	11
Net (losses) recoveries charged to allowance	(55)	(77)
Credit loss expense	65	69
Balance at the end of the period	291	264
Foreign. | Foreign
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at the beginning of the period	968	762
Credit loss expense	121	(50)
Balance at the end of the period	$ 1,089	$ 712

Allowance for Credit Losses (Im

Allowance for Credit Losses (Impairment By Loan Class) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	$ 51,809	$ 51,830
Loans Individually Evaluated for Impairment, Allowance	3,445	2,445
Loans Collectively Evaluated for Impairment, Recorded Investment	7,479,964	7,378,773
Loans Collectively Evaluated for Impairment, Allowance	130,112	123,527
Commercial, financial and agricultural | Domestic | Commercial.
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	30,529	30,747
Loans Individually Evaluated for Impairment, Allowance	3,375	2,375
Loans Collectively Evaluated for Impairment, Recorded Investment	1,467,573	1,468,006
Loans Collectively Evaluated for Impairment, Allowance	24,413	24,353
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	297	94
Loans Collectively Evaluated for Impairment, Recorded Investment	2,562,801	2,568,025
Loans Collectively Evaluated for Impairment, Allowance	36,556	36,474
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	110	117
Loans Collectively Evaluated for Impairment, Recorded Investment	309,435	306,384
Loans Collectively Evaluated for Impairment, Allowance	3,984	3,794
Obligations of states and political subdivisions | 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	20,481	20,483
Loans Individually Evaluated for Impairment, Allowance	70	70
Loans Collectively Evaluated for Impairment, Recorded Investment	2,060,657	1,969,186
Loans Collectively Evaluated for Impairment, Allowance	50,863	44,614
Real estate - mortgage | Domestic | Residential: first lien
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	74	77
Loans Collectively Evaluated for Impairment, Recorded Investment	419,481	425,647
Loans Collectively Evaluated for Impairment, Allowance	4,559	4,759
Real estate - mortgage | Domestic | Residential Junior Lien
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Individually Evaluated for Impairment, Recorded Investment	318	312
Loans Collectively Evaluated for Impairment, Recorded Investment	439,036	439,958
Loans Collectively Evaluated for Impairment, Allowance	8,357	8,284
Consumer | Domestic
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Collectively Evaluated for Impairment, Recorded Investment	43,390	41,592
Loans Collectively Evaluated for Impairment, Allowance	291	281
Foreign. | Foreign
Loan loss allowances, impaired financing receivable, evaluated individually or collectively
Loans Collectively Evaluated for Impairment, Recorded Investment	177,591	159,975
Loans Collectively Evaluated for Impairment, Allowance	$ 1,089	$ 968

Allowance for Credit Losses (No

Allowance for Credit Losses (Non-accrual Basis By Loan Class) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Loan loss allowances, financing receivable past due
Non-accrual loans, total	$ 51,632	$ 51,648
Commercial, financial and agricultural | Domestic | Commercial.
Loan loss allowances, financing receivable past due
Non-accrual loans, total	30,529	30,747
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial
Loan loss allowances, financing receivable past due
Non-accrual loans, total	297	94
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily
Loan loss allowances, financing receivable past due
Non-accrual loans, total	110	117
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development
Loan loss allowances, financing receivable past due
Non-accrual loans, total	20,481	20,483
Real estate - mortgage | Domestic | Residential: first lien
Loan loss allowances, financing receivable past due
Non-accrual loans, total	$ 215	$ 207

Allowance for Credit Losses (_2

Allowance for Credit Losses (Impaired Loans) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Loan loss allowances
Total troubled debt restructuring		$ 3,213
Period of charge off for past due unsecured commercial loans	90 days
Real estate - mortgage | Domestic | Residential: first lien
Loan loss allowances
Total troubled debt restructuring		1,642
Real estate - mortgage | Domestic | Residential Junior Lien
Loan loss allowances
Total troubled debt restructuring		714
Consumer | Domestic
Loan loss allowances
Total troubled debt restructuring		802
Foreign. | Foreign
Loan loss allowances
Total troubled debt restructuring		$ 55

Allowance for Credit Losses (Ag

Allowance for Credit Losses (Aging By Loan Class) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	$ 5,629	$ 6,132
Loans	7,531,773	7,430,603
Current
Financing receivable recorded investment
Loans	7,448,744	7,412,585
Total Past Due
Financing receivable recorded investment
Loans	83,029	18,018
30 to 59 Days
Financing receivable recorded investment
Loans	20,523	8,552
60 to 89 Days
Financing receivable recorded investment
Loans	6,234	2,251
90 Days or Greater
Financing receivable recorded investment
Loans	56,272	7,215
Commercial, financial and agricultural
Financing receivable recorded investment
Loans	4,370,745	4,373,373
Commercial, financial and agricultural | Domestic | Commercial.
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	121	59
Loans	1,498,102	1,498,754
Commercial, financial and agricultural | Domestic | Commercial. | Current
Financing receivable recorded investment
Loans	1,465,174	1,495,750
Commercial, financial and agricultural | Domestic | Commercial. | Total Past Due
Financing receivable recorded investment
Loans	32,928	3,004
Commercial, financial and agricultural | Domestic | Commercial. | 30 to 59 Days
Financing receivable recorded investment
Loans	2,162	1,732
Commercial, financial and agricultural | Domestic | Commercial. | 60 to 89 Days
Financing receivable recorded investment
Loans	217	258
Commercial, financial and agricultural | Domestic | Commercial. | 90 Days or Greater
Financing receivable recorded investment
Loans	30,549	1,014
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial
Financing receivable recorded investment
Loans	2,563,099	2,568,118
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Current
Financing receivable recorded investment
Loans	2,557,940	2,566,257
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Total Past Due
Financing receivable recorded investment
Loans	5,159	1,861
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | 30 to 59 Days
Financing receivable recorded investment
Loans	594	1,744
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | 60 to 89 Days
Financing receivable recorded investment
Loans	4,565	117
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily
Financing receivable recorded investment
Loans	309,544	306,501
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | Current
Financing receivable recorded investment
Loans	309,311	306,501
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | Total Past Due
Financing receivable recorded investment
Loans	233
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | 30 to 59 Days
Financing receivable recorded investment
Loans	233
Obligations of states and political subdivisions
Financing receivable recorded investment
Loans	2,081,138	1,989,669
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development
Financing receivable recorded investment
Loans	2,081,138	1,989,669
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Current
Financing receivable recorded investment
Loans	2,046,914	1,988,539
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Total Past Due
Financing receivable recorded investment
Loans	34,224	1,130
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | 30 to 59 Days
Financing receivable recorded investment
Loans	14,242	1,130
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | 90 Days or Greater
Financing receivable recorded investment
Loans	19,982
Real estate - mortgage
Financing receivable recorded investment
Loans	858,909	865,994
Real estate - mortgage | Domestic | Residential: first lien
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	2,864	4,061
Loans	419,555	425,724
Real estate - mortgage | Domestic | Residential: first lien | Current
Financing receivable recorded investment
Loans	414,116	418,444
Real estate - mortgage | Domestic | Residential: first lien | Total Past Due
Financing receivable recorded investment
Loans	5,439	7,280
Real estate - mortgage | Domestic | Residential: first lien | 30 to 59 Days
Financing receivable recorded investment
Loans	1,189	2,023
Real estate - mortgage | Domestic | Residential: first lien | 60 to 89 Days
Financing receivable recorded investment
Loans	1,153	1,068
Real estate - mortgage | Domestic | Residential: first lien | 90 Days or Greater
Financing receivable recorded investment
Loans	3,097	4,189
Real estate - mortgage | Domestic | Residential Junior Lien
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	2,051	1,717
Loans	439,354	440,270
Real estate - mortgage | Domestic | Residential Junior Lien | Current
Financing receivable recorded investment
Loans	435,810	436,857
Real estate - mortgage | Domestic | Residential Junior Lien | Total Past Due
Financing receivable recorded investment
Loans	3,544	3,413
Real estate - mortgage | Domestic | Residential Junior Lien | 30 to 59 Days
Financing receivable recorded investment
Loans	1,235	925
Real estate - mortgage | Domestic | Residential Junior Lien | 60 to 89 Days
Financing receivable recorded investment
Loans	258	771
Real estate - mortgage | Domestic | Residential Junior Lien | 90 Days or Greater
Financing receivable recorded investment
Loans	2,051	1,717
Consumer
Financing receivable recorded investment
Loans	43,390	41,592
Consumer | Domestic
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	12	7
Loans	43,390	41,592
Consumer | Domestic | Current
Financing receivable recorded investment
Loans	43,078	41,290
Consumer | Domestic | Total Past Due
Financing receivable recorded investment
Loans	312	302
Consumer | Domestic | 30 to 59 Days
Financing receivable recorded investment
Loans	270	281
Consumer | Domestic | 60 to 89 Days
Financing receivable recorded investment
Loans	30	14
Consumer | Domestic | 90 Days or Greater
Financing receivable recorded investment
Loans	12	7
Foreign.
Financing receivable recorded investment
Loans	177,591	159,975
Foreign. | Foreign
Financing receivable recorded investment
Past due 90 days or Greater and Still Accruing	581	288
Loans	177,591	159,975
Foreign. | Foreign | Current
Financing receivable recorded investment
Loans	176,401	158,947
Foreign. | Foreign | Total Past Due
Financing receivable recorded investment
Loans	1,190	1,028
Foreign. | Foreign | 30 to 59 Days
Financing receivable recorded investment
Loans	598	717
Foreign. | Foreign | 60 to 89 Days
Financing receivable recorded investment
Loans	11	23
Foreign. | Foreign | 90 Days or Greater
Financing receivable recorded investment
Loans	$ 581	$ 288

Allowance for Credit Losses (Po

Allowance for Credit Losses (Portfolio Credit Quality) (Details) $ in Thousands	Mar. 31, 2023 USD ($) loan	Dec. 31, 2022 USD ($)
Loan portfolio by credit quality indicator
2023	$ 1,072,045
2022	2,703,074	$ 3,048,975
2021	1,773,923	2,081,483
2020	828,049	988,625
2019	473,803	543,277
2018/Prior	680,879	468,848
Prior		299,395
Total loans	$ 7,531,773	7,430,603
Commercial real estate: farmland & commercial
Loan portfolio by credit quality indicator
Number of loans downgraded | loan	2
Commercial, financial and agricultural
Loan portfolio by credit quality indicator
Total loans	$ 4,370,745	4,373,373
Commercial, financial and agricultural | Domestic | Commercial.
Loan portfolio by credit quality indicator
2023	264,131
2022	589,634	766,789
2021	453,286	525,241
2020	87,778	97,498
2019	32,500	35,917
2018/Prior	70,773	43,841
Prior		29,468
Total loans	1,498,102	1,498,754
Commercial, financial and agricultural | Domestic | Commercial. | Pass
Loan portfolio by credit quality indicator
2023	263,913
2022	530,585	736,462
2021	452,955	524,879
2020	87,039	96,401
2019	32,481	35,917
2018/Prior	68,318	43,792
Prior		29,464
Total loans	1,435,291	1,466,915
Commercial, financial and agricultural | Domestic | Commercial. | Special Review
Loan portfolio by credit quality indicator
2022	371	377
2021	201	213
Total loans	572	590
Commercial, financial and agricultural | Domestic | Commercial. | Watch List - Substandard
Loan portfolio by credit quality indicator
2023	218
2022	28,889	161
2021	130	149
2020		143
2019	19
2018/Prior	2,454	49
Total loans	31,710	502
Commercial, financial and agricultural | Domestic | Commercial. | Watch List - Doubtful
Loan portfolio by credit quality indicator
2022	29,789	29,789
2020	739	954
2018/Prior	1
Prior		4
Total loans	30,529	30,747
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial
Loan portfolio by credit quality indicator
2023	294,941
2022	795,136	833,401
2021	539,297	584,381
2020	357,035	511,194
2019	229,067	232,633
2018/Prior	347,623	325,214
Prior		81,295
Total loans	2,563,099	2,568,118
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Pass
Loan portfolio by credit quality indicator
2023	294,941
2022	723,848	811,117
2021	534,498	584,134
2020	353,714	456,200
2019	228,974	232,537
2018/Prior	336,205	325,214
Prior		81,295
Total loans	2,472,180	2,490,497
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Special Review
Loan portfolio by credit quality indicator
2022	173	2,855
2020	835	842
Total loans	1,008	3,697
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Watch List - Pass
Loan portfolio by credit quality indicator
2022	16,986	17,060
2021	243	247
Total loans	17,229	17,307
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Watch List - Substandard
Loan portfolio by credit quality indicator
2022	54,038	2,275
2021	4,556
2020	2,486	54,152
2019	93	96
2018/Prior	11,212
Total loans	72,385	56,523
Commercial, financial and agricultural | Domestic | Commercial real estate: farmland & commercial | Watch List - Doubtful
Loan portfolio by credit quality indicator
2022	91	94
2018/Prior	206
Total loans	297	94
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily
Loan portfolio by credit quality indicator
2023	45,117
2022	125,140	127,797
2021	50,142	87,469
2020	58,802	59,035
2019	11,427	12,026
2018/Prior	18,916	5,490
Prior		14,684
Total loans	309,544	306,501
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | Pass
Loan portfolio by credit quality indicator
2023	45,117
2022	125,030	127,680
2021	50,142	87,469
2020	58,802	59,035
2019	11,427	12,026
2018/Prior	18,916	5,490
Prior		14,684
Total loans	309,434	306,384
Commercial, financial and agricultural | Domestic | Commercial real estate: multifamily | Watch List - Doubtful
Loan portfolio by credit quality indicator
2022	110	117
Total loans	110	117
Obligations of states and political subdivisions
Loan portfolio by credit quality indicator
Total loans	2,081,138	1,989,669
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development
Loan portfolio by credit quality indicator
2023	341,573
2022	860,150	933,657
2021	530,618	666,754
2020	186,718	173,918
2019	124,675	175,106
2018/Prior	37,404	35,069
Prior		5,165
Total loans	2,081,138	1,989,669
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Pass
Loan portfolio by credit quality indicator
2023	341,573
2022	840,168	913,675
2021	530,211	666,347
2020	186,626	173,824
2019	124,467	174,897
2018/Prior	37,404	35,069
Prior		5,165
Total loans	2,060,449	1,968,977
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Special Review
Loan portfolio by credit quality indicator
2019	208	209
Total loans	208	209
Obligations of states and political subdivisions | Domestic | Commercial Real Estate: other construction and land development | Watch List - Doubtful
Loan portfolio by credit quality indicator
2022	19,982	19,982
2021	407	407
2020	92	94
Total loans	20,481	20,483
Real estate - mortgage
Loan portfolio by credit quality indicator
Total loans	858,909	865,994
Real estate - mortgage | Domestic | Residential: first lien
Loan portfolio by credit quality indicator
2023	71,028
2022	97,981	138,848
2021	76,754	82,826
2020	45,420	49,591
2019	32,016	40,985
2018/Prior	96,356	33,814
Prior		79,660
Total loans	419,555	425,724
Real estate - mortgage | Domestic | Residential: first lien | Pass
Loan portfolio by credit quality indicator
2023	71,028
2022	97,907	138,771
2021	76,400	82,466
2020	45,354	49,591
2019	32,016	40,985
2018/Prior	96,356	33,814
Prior		79,660
Total loans	419,061	425,287
Real estate - mortgage | Domestic | Residential: first lien | Watch List - Substandard
Loan portfolio by credit quality indicator
2021	354	360
2020	66
Total loans	420	360
Real estate - mortgage | Domestic | Residential: first lien | Watch List - Doubtful
Loan portfolio by credit quality indicator
2022	74	77
Total loans	74	77
Real estate - mortgage | Domestic | Residential Junior Lien
Loan portfolio by credit quality indicator
2023	15,944
2022	91,262	92,256
2021	103,512	109,127
2020	86,758	91,130
2019	39,295	41,273
2018/Prior	102,583	21,975
Prior		84,509
Total loans	439,354	440,270
Real estate - mortgage | Domestic | Residential Junior Lien | Pass
Loan portfolio by credit quality indicator
2023	15,944
2022	90,944	92,256
2021	103,512	108,815
2020	86,758	91,130
2019	39,295	41,273
2018/Prior	102,583	21,975
Prior		84,509
Total loans	439,036	439,958
Real estate - mortgage | Domestic | Residential Junior Lien | Watch List - Doubtful
Loan portfolio by credit quality indicator
2022	318
2021		312
Total loans	318	312
Consumer
Loan portfolio by credit quality indicator
Total loans	43,390	41,592
Consumer | Domestic
Loan portfolio by credit quality indicator
2023	12,176
2022	24,278	31,962
2021	4,412	6,603
2020	542	897
2019	344	489
2018/Prior	1,638	28
Prior		1,613
Total loans	43,390	41,592
Consumer | Domestic | Pass
Loan portfolio by credit quality indicator
2023	12,176
2022	24,278	31,962
2021	4,412	6,603
2020	542	897
2019	344	489
2018/Prior	1,638	28
Prior		1,613
Total loans	43,390	41,592
Foreign.
Loan portfolio by credit quality indicator
Total loans	177,591	159,975
Foreign. | Foreign
Loan portfolio by credit quality indicator
2023	27,135
2022	119,493	124,265
2021	15,902	19,082
2020	4,996	5,362
2019	4,479	4,848
2018/Prior	5,586	3,417
Prior		3,001
Total loans	177,591	159,975
Foreign. | Foreign | Pass
Loan portfolio by credit quality indicator
2023	27,135
2022	119,493	124,265
2021	15,902	19,082
2020	4,996	5,362
2019	4,479	4,848
2018/Prior	5,586	3,417
Prior		3,001
Total loans	$ 177,591	$ 159,975

Stock Options and Stock Appre_3

Stock Options and Stock Appreciation Rights - Options (Details) - USD ($)		3 Months Ended
	Apr. 18, 2022	Mar. 31, 2023	Mar. 31, 2022	Apr. 05, 2012
Employee Stock Options
Stock Options, Aggregate intrinsic value
Stock-based compensation expense		$ 102,000	$ 121,000
Employee Stock Options | 2012 Plan
Stock option details
Shares available for future grants				800,000
Maximum exercisable period for granted share-based compensation		10 years
Stock option activity
Options outstanding at the beginning of the period (in shares)		461,822
Less:
Exercise of stock options (in shares)		3,537
Options forfeited (in shares)		2,938
Options outstanding at the end of the period (in shares)		455,347
Options fully vested and exercisable at the end of the period (in shares)		257,932
Stock Options, Weighted average exercise price
Options outstanding at the beginning, weighted average exercise price (in dollars per share)		$ 29.67
Less:
Options exercised, weighted average exercise price (in dollars per share)		24
Options forfeited, weighted average exercise price (in dollars per share)		36.51
Options outstanding at the end, weighted average exercise price (in dollars per share)		29.67
Options fully vested and exercisable at the end, weighted average exercise price (in dollars per share)		$ 25.20
Stock Options, Weighted average remaining contractual term (years)
Options outstanding at the end, weighted average remaining contractual term (years)		3 years 9 months 25 days
Options fully vested and exercisable at the end, weighted average remaining contractual term (years)		2 years 21 days
Stock Options, Aggregate intrinsic value
Options outstanding at the end, aggregate intrinsic value		$ 5,987,000
Options fully vested and exercisable at the end, aggregate intrinsic value		4,545,000
Stock-based compensation cost, unrecognized, related to non-vested options		$ 660,000
Stock-based compensation cost, unrecognized, related to non-vested options, weighted-average period of recognition		1 year 7 months 6 days
Stock Appreciation Rights
Stock Options, Aggregate intrinsic value
Stock-based compensation expense			$ 166,000
Stock Appreciation Rights | SAR Plan
Stock option details
Shares available for future grants	750,000
Maximum exercisable period for granted share-based compensation	10 years
Number of rights issued		502,250
Vesting period	8 years
Incentive Stock Options to 10 Percent Shareholders | 2012 Plan
Stock option details
Maximum exercisable period for granted share-based compensation		5 years

Stock Options and Stock Appre_4

Stock Options and Stock Appreciation Rights - SARs (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
	Apr. 18, 2022	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
SARs
Outstanding beginning balance		489,250
Forfeited			5,750
Outstanding ending balance			483,500
Weighted average exercise price
Weighted average exercise price, beginning balance (per share)		$ 39.35
Weighted average exercise price, forfeited (per share)			$ 39.33
Weighted average exercise price, ending balance (per share)			$ 39.35
Aggregate intrinsic value
Aggregate intrinsic value			$ 1,680
Weighted average remaining contractual term (years)			9 years 6 months
Stock Appreciation Rights
Aggregate intrinsic value
Fair Value of Liability				$ 712
Stock-based compensation expense			$ 166
Stock Appreciation Rights | SAR Plan
Stock option details
Shares available for future grants	750,000
Maximum exercisable period for granted share-based compensation	10 years
Number of rights issued		502,250
Vesting period	8 years
SARs
Granted		502,250

Investment Securities, Equity_3

Investment Securities, Equity Securities with Readily Determinable Fair Values and Other Investments (Details) - USD ($)	Mar. 31, 2023	Dec. 31, 2022
Held-to-maturity securities
Amortized cost	$ 3,400,000	$ 3,400,000
Estimated fair value	3,400,000	3,400,000
Carrying Value	3,400,000	3,400,000
Available-for-sale securities
Amortized cost	5,397,131,000	5,018,996,000
Estimated fair value, Available for sale securities	4,859,818,000	4,417,796,000
Total Amortized cost	5,397,131,000	5,018,996,000
Total Gross unrealized gains	6,774,000	4,072,000
Total Gross unrealized losses	544,087,000	605,272,000
Collateral Pledged
Available-for-sale securities
Amortized cost	1,428,702,000
Estimated Fair Value
Available-for-sale securities
Available for sale debt securities and equity securities	4,859,818,000	4,417,796,000
Reported Value Measurement
Available-for-sale securities
Available for sale debt securities and equity securities	4,859,818,000	4,417,796,000
US Treasury Securities
Available-for-sale securities
Amortized cost	49,967,000	49,752,000
Gross unrealized losses	(42,000)	(359,000)
US Treasury Securities | Estimated Fair Value
Available-for-sale securities
Estimated fair value, Available for sale securities	49,925,000	49,393,000
US Treasury Securities | Reported Value Measurement
Available-for-sale securities
Estimated fair value, Available for sale securities	49,925,000	49,393,000
Residential mortgage-backed securities
Available-for-sale securities
Amortized cost	5,184,217,000	4,805,735,000
Gross unrealized gains	5,289,000	3,145,000
Gross unrealized losses	(542,277,000)	(599,668,000)
Residential mortgage-backed securities | Estimated Fair Value
Available-for-sale securities
Estimated fair value, Available for sale securities	4,647,229,000	4,209,212,000
Residential mortgage-backed securities | Reported Value Measurement
Available-for-sale securities
Estimated fair value, Available for sale securities	4,647,229,000	4,209,212,000
US Government Corporations and Agencies Securities [Member]
Available-for-sale securities
Estimated fair value, Available for sale securities	810,907,000	681,121,000
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale securities
Estimated fair value, Available for sale securities	3,836,322,000	3,528,091,000
States and political subdivisions
Available-for-sale securities
Amortized cost	162,947,000	163,509,000
Gross unrealized gains	1,485,000	927,000
Gross unrealized losses	(1,768,000)	(5,245,000)
States and political subdivisions | Estimated Fair Value
Available-for-sale securities
Estimated fair value, Available for sale securities	162,664,000	159,191,000
States and political subdivisions | Reported Value Measurement
Available-for-sale securities
Estimated fair value, Available for sale securities	162,664,000	159,191,000
Other Debt Obligations
Held-to-maturity securities
Amortized cost	3,400,000	3,400,000
Estimated fair value	3,400,000	3,400,000
Carrying Value	$ 3,400,000	$ 3,400,000

Investment Securities, Equity_4

Investment Securities, Equity Securities with Readily Determinable Fair Values and Other Investments (Contractual Maturities and Estimated Fair Values) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Amortized Cost
Due in one year or less, held-to-maturity debt securities amortized cost	$ 1,075,000
Due after one year through five years, held-to-maturity debt securities amortized cost	2,325,000
Amortized cost, held-to-maturity debt securities	3,400,000		$ 3,400,000
Fair Value
Due in one year or less, held-to-maturity debt securities, Estimated fair value	1,075,000
Due after one year through five years, held-to-maturity debt securities, Estimated fair value	2,325,000
Estimated fair value	3,400,000		3,400,000
Available-for-sale debt securities amortized cost disclosures
Due in one year or less, available-for-sale debt securities amortized cost	49,967,000
Due after five years through ten years, available-for-sale debt securities amortized cost	440,000
Due after ten years, available-for-sale debt securities amortized cost	162,507,000
Residential mortgage-backed securities, amortized cost	5,184,217,000
Amortized cost, Available for sale securities	5,397,131,000		$ 5,018,996,000
Available for sale debt securities, Estimated Fair Value Disclosures
Due in one year or less, available-for-sale debt securities, Estimated Fair Value	49,925,000
Due after five years through ten years, available-for-sale debt securities, Estimated Fair Value	440,000
Due after ten years, available-for-sale debt securities, Estimated Fair Value	162,224,000
Residential mortgage-backed securities, Estimated Fair Value	4,647,229,000
Available for sale debt securities, Estimated Fair Value Disclosures
Proceeds from sales and calls of available for sale securities	450,000	$ 0
Proceeds from sales of mortgage-backed securities	0	0
Gross gains realized on sales	0	0
Gross losses realized on sales	0	$ 0
Collateral Pledged
Available for sale debt securities, Estimated Fair Value Disclosures
Fair value of available for sale investment securities pledged	$ 1,249,080,000

Investment Securities, Equity_5

Investment Securities, Equity Securities with Readily Determinable Fair Values and Other Investments (Unrealized Losses) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Available for sale:
Fair value, less than 12 months	$ 1,593,958	$ 1,526,071
Unrealized losses, less than 12 Months	(45,986)	(93,419)
Fair value, 12 months or more	2,969,348	2,566,975
Unrealized losses, 12 Months or More	(498,101)	(511,853)
Fair value, Total	4,563,306	4,093,046
Unrealized losses, Total	(544,087)	(605,272)
US Treasury Securities
Available for sale:
Fair value, less than 12 months	49,925	49,394
Unrealized losses, less than 12 Months	(42)	(359)
Fair value, Total	49,925	49,394
Unrealized losses, Total	(42)	(359)
Residential mortgage-backed securities
Available for sale:
Fair value, less than 12 months	1,438,275	1,357,905
Unrealized losses, less than 12 Months	(44,176)	(87,815)
Fair value, 12 months or more	2,969,348	2,566,975
Unrealized losses, 12 Months or More	(498,101)	(511,853)
Fair value, Total	4,407,623	3,924,880
Unrealized losses, Total	(542,277)	(599,668)
States and political subdivisions
Available for sale:
Fair value, less than 12 months	105,758	118,772
Unrealized losses, less than 12 Months	(1,768)	(5,245)
Fair value, Total	105,758	118,772
Unrealized losses, Total	$ (1,768)	$ (5,245)

Investment Securities, Equity_6

Investment Securities, Equity Securities with Readily Determinable Fair Values and Other Investments (Unrealized and realized gains and losses recognized in net income on equity securities ) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Investment Securities, Equity Securities with Readily Determinable Fair Values and Other Investments
Equity Securities	$ 5,392,000		$ 5,358,000
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	34,000	$ (269,000)
Unrealized gain on equity securities with readily determinable fair values	$ 34,000	$ (269,000)

Investment Securities (Other In

Investment Securities (Other Investments) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Other investments
LIHTC
Investments	$ 214,549
Other liabilities
LIHTC
Unfunded commitments	$ 37,357	$ 41,191

Other Borrowed Funds (Details)

Other Borrowed Funds (Details) - USD ($)	Mar. 31, 2023	Dec. 31, 2022
Federal Home Loan Bank advances
Other borrowed funds	$ 10,895,000	$ 10,944,000

Junior Subordinated Deferrabl_3

Junior Subordinated Deferrable Interest Debentures (Details)	3 Months Ended
	Mar. 31, 2023 USD ($) item	Dec. 31, 2022 USD ($)
Junior Subordinated Deferrable Interest Debentures
Number of statutory business trusts issuing trust preferred securities | item	5
Junior subordinated deferrable interest debentures | $	$ 134,642,000	$ 134,642,000
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%
Percentage of capital securities issued by trust qualifying as Tier II capital, minimum	25%
Capital securities issued by the trust, qualifying as Tier I capital | $	$ 134,642,000	$ 134,642,000

Junior Subordinated Deferrabl_4

Junior Subordinated Deferrable Interest Debentures (Key Information) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Junior subordinated interest deferrable debentures, major types of business trusts
Junior subordinated deferrable interest debentures	$ 134,642,000	$ 134,642,000
Trust VIII
Junior subordinated interest deferrable debentures, major types of business trusts
Junior subordinated deferrable interest debentures	$ 25,774,000
Interest rate (as a percent)	7.88%
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	$ 41,238,000
Interest rate (as a percent)	6.37%
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	$ 21,021,000
Interest rate (as a percent)	6.46%
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	$ 25,990,000
Interest rate (as a percent)	6.37%
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	$ 20,619,000
Interest rate (as a percent)	6.41%
Interest rate index	LIBOR
Spread on interest rate index (as a percent)	1.45%

Common Stock and Dividends (Det

Common Stock and Dividends (Details) - USD ($)					1 Months Ended
	Feb. 28, 2023	Oct. 31, 2022	Feb. 28, 2022	Feb. 23, 2022	Apr. 30, 2009	Feb. 21, 2023
Common Stock and Dividends
Cash dividends paid to common shareholders (in dollars per share)	$ 0.63		$ 0.60
Repurchase of common stock, authorized amount					$ 40,000,000	$ 124,000,000
Period of repurchase of common stock				12 months	12 months
Cumulative number of shares repurchased under all stock repurchase programs		13,615,730
Cumulative cost of shares repurchased under all stock repurchase programs		$ 411,099,000

Capital Requirements (Capital A

Capital Requirements (Capital Amounts and Ratios) (Details)	Mar. 31, 2023	Dec. 31, 2022
Capital Requirements
CET 1 ratio	0.2043	0.2021
Total Capital (to Risk Weighted Assets), Actual Ratio (as a percent)	0.2260	0.2222
Tier 1 capital (to Risk Weighted Assets), Actual Ratio (as a percent)	0.2137	0.2104
Tier 1 capital (to Average Assets), Actual Ratio (as a percent)	0.1561	0.1459