Cullen/Frost Bankers (CFR) 10-K 6 Feb 25 2024 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ / shares in Units, $ in Billions	12 Months Ended
	Dec. 31, 2024	Jan. 30, 2025	Jun. 30, 2024	Dec. 31, 2023
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2024
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Transition Report	false
Entity File Number	001-13221
Entity Registrant Name	CULLEN/FROST BANKERS, INC.
Entity Incorporation, State or Country Code	TX
Entity Tax Identification Number	74-1751768
Entity Address, Address Line One	111 W. Houston Street,
Entity Address, City or Town	San Antonio,
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	78205
City Area Code	(210)
Local Phone Number	220-4011
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 6.4
Entity Common Stock, Shares Outstanding		64,235,032
Common Stock, Par or Stated Value Per Share	$ 0.01			$ 0.01
Entity Central Index Key	0000039263
Amendment Flag	false
Document Fiscal Period Focus	FY
Auditor Name	Ernst & Young LLP
Auditor Location	San Antonio, Texas
Auditor Firm ID	42
Common Stock [Member] | NEW YORK STOCK EXCHANGE, INC. [Member]
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, $.01 Par Value
Trading Symbol	CFR
Security Exchange Name	NYSE
Series B Preferred Stock [Member] | NEW YORK STOCK EXCHANGE, INC. [Member]
Entity Information [Line Items]
Title of 12(b) Security	Depositary Shares, each representing a 1/40th interest in a share of 4.450% Non-Cumulative Perpetual Preferred Stock, Series B
Trading Symbol	CFR.PrB
Security Exchange Name	NYSE

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Assets:
Cash and due from banks	$ 722,906	$ 617,569
Interest-bearing deposits	9,495,777	7,985,057
Federal funds sold	5,925	0
Resell agreements	9,650	84,650
Total cash and cash equivalents	10,234,258	8,687,276
Securities held to maturity, net of allowance for credit losses of $310 at both 2024 and 2023	3,533,775	3,619,428
Securities available for sale, at estimated fair value	15,043,625	16,578,371
Trading account securities	33,910	31,717
Loans, net of unearned discounts	20,754,813	18,824,251
Less: Allowance for credit losses on loans	(270,151)	(245,996)
Net loans	20,484,662	18,578,255
Premises and equipment, net	1,245,377	1,190,033
Accrued interest receivable and other assets	1,944,652	2,159,958
Total assets	52,520,259	50,845,038
Liabilities:
Non-interest-bearing demand deposits	14,441,820	14,926,094
Interest-bearing deposit	28,280,928	26,994,474
Total deposits	42,722,748	41,920,568
Federal funds purchased	21,975	14,200
Repurchase agreements	4,342,941	4,127,188
Junior subordinated deferrable interest debentures, net of unamortized issuance costs	123,184	123,127
Subordinated notes, net of unamortized issuance costs	99,648	99,491
Accrued interest payable and other liabilities	1,311,175	844,017
Total liabilities	48,621,671	47,128,591
Shareholders’ Equity:
Preferred stock, par value $0.01 per share; 10,000,000 shares authorized; 150,000 Series B shares ($1,000 liquidation preference) issued in 2024 and 2023	145,452	145,452
Common stock, par value $0.01 per share; 210,000,000 shares authorized; 64,404,582 shares issued in both 2024 and 2023	644	644
Additional paid-in capital	1,075,572	1,055,809
Retained earnings	3,951,482	3,657,688
Accumulated other comprehensive income (loss), net of tax	(1,252,004)	(1,119,219)
Treasury stock, at cost; 207,150 shares in 2024 and 219,295 in 2023	(22,558)	(23,927)
Total shareholders’ equity	3,898,588	3,716,447
Total liabilities and shareholders’ equity	$ 52,520,259	$ 50,845,038

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($)	Dec. 31, 2024	Dec. 31, 2023
Debt Securities, Held-to-maturity, Allowance for Credit Loss	$ (310,000)	$ (310,000)
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	210,000,000	210,000,000
Common Stock, Shares, Issued	64,404,582	64,404,582
Treasury Stock, Common Shares	207,150	219,295
Series B Preferred Stock [Member]
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	10,000,000	10,000,000
Preferred Stock, Shares Issued	150,000	150,000
Preferred Stock, Liquidation Preference, Value	$ 1,000	$ 1,000

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Interest income:
Loans, including fees	$ 1,375,442	$ 1,189,377	$ 770,391
Securities:
Taxable	396,224	406,289	249,797
Tax-exempt	218,177	240,131	237,626
Interest-bearing deposits	397,414	376,010	216,367
Federal funds sold	270	1,288	948
Resell agreements	3,110	4,621	592
Total interest income	2,390,637	2,217,716	1,475,721
Interest expense:
Deposits	629,107	508,255	140,476
Federal funds purchased	1,556	1,524	690
Repurchase agreements	141,833	135,969	34,443
Junior subordinated deferrable interest debentures	8,872	8,647	4,172
Subordinated notes	4,657	4,657	4,657
Total interest expense	786,025	659,052	184,438
Net interest income	1,604,612	1,558,664	1,291,283
Credit loss expense	64,985	46,171	3,000
Net interest income after credit loss expense	1,539,627	1,512,493	1,288,283
Non-interest income:
Trust and investment management fees	165,270	153,315	154,679
Service charges on deposit accounts	106,230	93,504	91,891
Insurance commissions and fees	61,269	58,271	53,210
Interchange and card transaction fees	21,017	19,419	18,231
Other charges, commissions and fees	53,348	49,026	41,590
Net gain (loss) on securities transactions	(96)	66	0
Other	52,060	54,941	45,217
Total non-interest income	459,098	428,542	404,818
Non-interest expense:
Salaries and wages	621,394	547,718	492,096
Employee benefits	122,446	115,306	88,608
Net occupancy	128,751	124,396	112,495
Technology, furniture and equipment	148,487	135,286	120,771
Deposit insurance	37,269	76,589	15,603
Other	244,411	229,367	194,701
Total non-interest expense	1,302,758	1,228,662	1,024,274
Income before income taxes	695,967	712,373	668,827
Income taxes	113,425	114,400	89,677
Net income	582,542	597,973	579,150
Preferred stock dividends	6,675	6,675	6,675
Net income available to common shareholders	$ 575,867	$ 591,298	$ 572,475
Earnings per common share:
Basic (in dollars per share)	$ 8.88	$ 9.11	$ 8.84
Diluted (in dollars per share)	$ 8.87	$ 9.10	$ 8.81

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Net income (loss)	$ 582,542	$ 597,973	$ 579,150
Other comprehensive income (loss), before tax:
Change in net unrealized gain/loss on securities available for sale during the period	(171,662)	277,926	(2,143,567)
Change in net unrealized gain on securities transferred to held-to-maturity	(629)	(649)	(737)
Reclassification adjustment for net (gains) losses included in net income	96	(66)	0
Total securities available for sale and transferred securities before tax amount	(172,195)	277,211	(2,144,304)
Defined-benefit post-retirement benefit plans:
Change in the net actuarial gain/loss before tax amount	2,439	9,278	(5,005)
Reclassification adjustment for net amortization of actuarial gain/loss included in net income as a component of net periodic cost (benefit) before tax amount	1,673	3,479	2,964
Total defined-benefit post-retirement benefit plans	4,112	12,757	(2,041)
Reclassification adjustments for (gains) losses included in net income:
Other comprehensive income (loss), before tax	(168,083)	289,968	(2,146,345)
Deferred tax expense (benefit)	(35,298)	60,893	(450,733)
Other comprehensive income (loss), net of tax	(132,785)	229,075	(1,695,612)
Comprehensive income (loss)	$ 449,757	$ 827,048	$ (1,116,462)

Consolidated Statement of Chang

Consolidated Statement of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss), Net of Tax [Member]	Treasury Stock, Common
Balance at Dec. 31, 2021	$ 4,439,555	$ 145,452	$ 642	$ 1,009,921	$ 2,956,966	$ 347,318	$ (20,744)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	579,150				579,150
Other comprehensive income, net of tax	(1,695,612)					(1,695,612)
Proceeds from stock option exercises/stock unit conversions (589,782 shares, 267,357 shares, and 399,810 shares during 2024, 2023, and 2022, respectively)	16,659		1	1,513	(9,990)		25,135
Stock-based compensation expense recognized in earnings	18,322			18,322
Purchase of treasury stock (577,637 shares, 436,765 shares, and 31,351 shares during 2024, 2023, and 2022, respectively)	(4,391)						(4,391)
Cash dividends paid on preferred stock (approximately $44.50 per share which is equivalent to approximately $1.11 per depositary share in 2024, 2023, and 2022)	(6,675)				(6,675)
Cash dividends – common stock ($3.74 per share, $3.58 per share, and $3.24 per share in 2024, 2023, and 2022, respectively)	(209,780)				(209,780)
Balance at Dec. 31, 2022	3,137,228	145,452	643	1,029,756	3,309,671	(1,348,294)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	597,973				597,973
Other comprehensive income, net of tax	229,075					229,075
Proceeds from stock option exercises/stock unit conversions (589,782 shares, 267,357 shares, and 399,810 shares during 2024, 2023, and 2022, respectively)	9,299		1	1,463	(10,958)		18,793
Stock-based compensation expense recognized in earnings	24,590			24,590
Purchase of treasury stock (577,637 shares, 436,765 shares, and 31,351 shares during 2024, 2023, and 2022, respectively)	(42,720)						(42,720)
Cash dividends paid on preferred stock (approximately $44.50 per share which is equivalent to approximately $1.11 per depositary share in 2024, 2023, and 2022)	(6,675)				(6,675)
Cash dividends – common stock ($3.74 per share, $3.58 per share, and $3.24 per share in 2024, 2023, and 2022, respectively)	(232,323)				(232,323)
Balance at Dec. 31, 2023	3,716,447	145,452	644	1,055,809	3,657,688	(1,119,219)	(23,927)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	582,542				582,542
Other comprehensive income, net of tax	(132,785)					(132,785)
Proceeds from stock option exercises/stock unit conversions (589,782 shares, 267,357 shares, and 399,810 shares during 2024, 2023, and 2022, respectively)	22,643				(39,627)		62,270
Stock-based compensation expense recognized in earnings	19,763			19,763
Purchase of treasury stock (577,637 shares, 436,765 shares, and 31,351 shares during 2024, 2023, and 2022, respectively)	(60,901)						(60,901)
Cash dividends paid on preferred stock (approximately $44.50 per share which is equivalent to approximately $1.11 per depositary share in 2024, 2023, and 2022)	(6,675)				(6,675)
Cash dividends – common stock ($3.74 per share, $3.58 per share, and $3.24 per share in 2024, 2023, and 2022, respectively)	(242,446)				(242,446)
Balance at Dec. 31, 2024	$ 3,898,588	$ 145,452	$ 644	$ 1,075,572	$ 3,951,482	$ (1,252,004)	$ (22,558)

Consolidated Statement of Cha_2

Consolidated Statement of Changes in Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Stock option exercises/deferred stock unit conversions, shares	589,782	267,357	399,810
Treasury Stock, Shares, Acquired			0
Preferred Stock, Dividends Per Share, Declared	$ 44.50	$ 44.50	$ 44.50
Preferred stock, Dividends equivalent per depositary share, Declared	1.11	1.11	1.11
Common Stock, Dividends, Per Share, Cash Paid	$ 3.74	$ 3.58	$ 3.24
Treasury Stock, Common
Treasury Stock, Shares, Acquired	577,637	436,765	31,351
Share awards vesting | Treasury Stock, Common
Treasury Stock, Shares, Acquired	87,775	35,897	31,351

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating Activities:
Net income (loss)	$ 582,542	$ 597,973	$ 579,150
Adjustments to reconcile net income to net cash from operating activities:
Credit loss expense	64,985	46,171	3,000
Deferred tax expense (benefit)	(11,600)	(14,829)	(4,918)
Accretion of loan discounts	(23,951)	(17,724)	(12,921)
Securities premium amortization (discount accretion), net	45,213	63,893	97,400
Net (gain) loss on securities transactions	96	(66)	0
Depreciation and amortization	82,817	76,442	71,344
Net (gain) loss on sale/exchange/write-down of assets/foreclosed assets	(141)	750	109
Stock-based compensation	19,763	24,590	18,322
Net tax benefit from stock-based compensation	3,795	894	4,602
Earnings on life insurance policies	(3,745)	(2,944)	(2,096)
Net change in:
Trading account securities	(3,644)	(2,220)	(716)
Lease right-of-use assets	25,264	23,573	24,409
Accrued interest receivable and other assets	259,142	(232,665)	(116,243)
Accrued interest payable and other liabilities	(51,004)	(84,993)	61,140
Net cash provided by (used in) operating activities	989,532	478,845	722,582
Investing Activities:
Securities held to maturity: Purchases	0	(1,147,624)	(1,424,105)
Securities held to maturity: Maturities, calls and principal repayments	81,750	162,142	561,388
Securities available for sale:
Purchases	(17,899,779)	(19,124,336)	(22,178,248)
Sales	123,254	1,904,067	0
Maturities, calls and principal repayments	19,600,708	19,103,872	15,683,097
Proceeds from sale of loans	3,323	15,851	2,365
Net change in loans	(1,966,111)	(1,701,895)	(824,021)
Net cash paid in insurance agency asset acquisitions	(703)	0	0
Benefits received on life insurance policies	1,823	1,937	2,047
Proceeds from sales of premises and equipment	25	1,282	63
Purchases of premises and equipment	(127,776)	(158,630)	(102,501)
Proceeds from sales of repossessed properties	2,607	583	2,585
Net cash provided by (used in) investing activities	(180,879)	(942,751)	(8,277,330)
Financing Activities:
Net change in deposits	802,180	(2,033,628)	1,258,500
Net change in short-term borrowings	223,528	(570,903)	1,945,567
Proceeds from stock option exercises	22,643	9,299	16,659
Purchase of treasury stock	(60,901)	(42,720)	(4,391)
Cash dividends paid on preferred stock	(6,675)	(6,675)	(6,675)
Cash dividends paid on common stock	(242,446)	(232,323)	(209,780)
Net cash provided by (used in) financing activities	738,329	(2,876,950)	2,999,880
Net change in cash and cash equivalents	1,546,982	(3,340,856)	(4,554,868)
Cash and cash equivalents at beginning of year	8,687,276	12,028,132	16,583,000
Cash and cash equivalents at end of year	$ 10,234,258	$ 8,687,276	$ 12,028,132

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Nature of Operations . Cullen/Frost Bankers, Inc. (“Cullen/Frost”) is a financial holding company and a bank holding company headquartered in San Antonio, Texas that provides, through its subsidiaries, a broad array of products and services throughout numerous Texas markets. The terms “Cullen/Frost,” “the Corporation,” “we,” “us” and “our” mean Cullen/Frost Bankers, Inc. and its subsidiaries, when appropriate. In addition to general commercial and consumer banking, other products and services offered include trust and investment management, insurance, brokerage, mutual funds, leasing, treasury management, capital markets advisory and item processing. Basis of Presentation. The consolidated financial statements include the accounts of Cullen/Frost and all other entities in which Cullen/Frost has a controlling financial interest. All significant intercompany balances and transactions have been eliminated in consolidation. The accounting and financial reporting policies we follow conform, in all material respects, to accounting principles generally accepted in the United States and to general practices within the financial services industry. We determine whether we have a controlling financial interest in an entity by first evaluating whether the entity is a voting interest entity or a variable interest entity (“VIE”) under accounting principles generally accepted in the United States. Voting interest entities are entities in which the total equity investment at risk is sufficient to enable the entity to finance itself independently and provides the equity holders with the obligation to absorb losses, the right to receive residual returns and the right to make decisions about the entity’s activities. We consolidate voting interest entities in which we have all, or at least a majority of, the voting interest. As defined in applicable accounting standards, VIEs are entities that lack one or more of the characteristics of a voting interest entity. A controlling financial interest in a VIE is present when an enterprise has both the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and an obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. The enterprise with a controlling financial interest, known as the primary beneficiary, consolidates the VIE. Our wholly-owned subsidiary, Cullen/Frost Capital Trust II, is a VIE for which we are not the primary beneficiary and, as such, its accounts are not included in our consolidated financial statements. Acquisitions are accounted for using the purchase method with the operating results of the acquired companies included with our results of operations since their respective dates of acquisition. We have evaluated subsequent events for potential recognition and/or disclosure through the date these consolidated financial statements were issued. Use of Estimates . The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates. The allowance for credit losses on loans and off-balance-sheet credit exposures, the fair values of financial instruments and the status of contingencies are particularly subject to change. Concentrations and Restrictions on Cash and Cash Equivalents . We maintain deposits with other financial institutions in amounts that exceed federal deposit insurance coverage. Furthermore, federal funds sold are essentially uncollateralized loans to other financial institutions. Management regularly evaluates the credit risk associated with the counterparties to these transactions and believes that we are not exposed to any significant credit risks on cash and cash equivalents. As of December 31, 2024 and 2023, we had $350 thousand and $8.6 million in cash collateral on deposit with other financial institution counterparties to interest rate swap transactions. Cash Flow Reporting . Cash and cash equivalents include cash, deposits with other financial institutions that have an initial maturity of less than 90 days when acquired by us, federal funds sold and resell agreements. Net cash flows are reported for loans, deposit transactions and short-term borrowings. Additional cash flow information was as follows: Year Ended December 31, 2024 2023 2022 Cash paid for interest $ 788,377 $ 616,274 $ 169,020 Cash paid for income tax 122,000 118,000 100,000 Significant non-cash transactions: Unsettled securities transactions 501,587 1,452 94,884 Loans foreclosed and transferred to other real estate owned and foreclosed assets 19,297 — 239 Right-of-use lease assets obtained in exchange for lessee operating lease liabilities 15,044 15,259 31,787 Repurchase/Resell Agreements. We purchase certain securities under agreements to resell. The amounts advanced under these agreements represent short-term loans and are reflected as assets in the accompanying consolidated balance sheets. The securities underlying these agreements are book-entry securities. We also sell certain securities under agreements to repurchase. The agreements are treated as collateralized financing transactions and the obligations to repurchase securities sold are reflected as a liability in the accompanying consolidated balance sheets. The dollar amount of the securities underlying the agreements remains in the asset accounts. Securities. Securities are classified as held to maturity and carried at amortized cost when management has the positive intent and ability to hold them until maturity. Securities to be held for indefinite periods of time are classified as available for sale and carried at fair value, with the unrealized holding gains and losses (those for which no allowance for credit losses are recorded) reported as a component of other comprehensive income, net of tax. Securities held for resale in anticipation of short-term market movements are classified as trading and are carried at fair value, with changes in unrealized holding gains and losses included in income. Management determines the appropriate classification of securities at the time of purchase. Securities with limited marketability, such as stock in the Federal Reserve Bank and the Federal Home Loan Bank, are carried at cost. Interest income on securities includes amortization of purchase premiums and discounts. Premiums and discounts on securities are generally amortized using the interest method with a constant effective yield without anticipating prepayments, except for mortgage-backed securities where prepayments are anticipated. Premiums on callable securities are amortized to their earliest call date. A security is placed on non-accrual status if (i) principal or interest has been in default for a period of 90 days or more or (ii) full payment of principal and interest is not expected. Interest accrued but not received for a security placed on non-accrual status is reversed against interest income. Gains and losses on sales are recorded on the trade date and are derived from the amortized cost of the security sold. Loans . Loans are reported at the principal balance outstanding net of unearned discounts. Interest income on loans is reported on the level-yield method and includes amortization of deferred loan fees and costs over the terms of the individual loans to which they relate, or, in certain cases, over the average expected term for loans where deferred fees and costs are accounted for on a pooled basis. Net loan commitment fees or costs for commitment periods greater than one year are deferred and amortized into fee income or other expense on a straight-line basis over the commitment period. Income on direct financing leases is recognized on a basis that achieves a constant periodic rate of return on the outstanding investment. Further information regarding our accounting policies related to past due loans, non-accrual loans, and loan modifications to borrowers experiencing financial difficulty is presented in Note 3 - Loans. Allowance For Credit Losses - Held-to-Maturity Securities. The allowance for credit losses on held-to-maturity securities is a contra-asset valuation account, calculated in accordance with Accounting Standards Codification (“ASC”) Topic 326 (“ASC 326”), that is deducted from the amortized cost basis of held-to-maturity securities to present management's best estimate of the net amount expected to be collected. Held-to-maturity securities are charged-off against the allowance when deemed uncollectible by management. Adjustments to the allowance are reported in our income statement as a component of credit loss expense. Management measures expected credit losses on held-to-maturity securities on a collective basis by major security type with each type sharing similar risk characteristics and considers historical credit loss information that is adjusted for current conditions and reasonable and supportable forecasts. Management has made the accounting policy election to exclude accrued interest receivable on held-to-maturity securities from the estimate of credit losses. Further information regarding our policies and methodology used to estimate the allowance for credit losses on held-to-maturity securities is presented in Note 2 - Securities. Allowance For Credit Losses - Available-for-Sale Securities. For available-for-sale securities in an unrealized loss position, we first assess whether (i) we intend to sell or (ii) it is more likely than not that we will be required to sell the security before recovery of its amortized cost basis. If either case is affirmative, any previously recognized allowances are charged-off and the security's amortized cost is written down to fair value through income. If neither case is affirmative, the security is evaluated to determine whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, management considers the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency and any adverse conditions specifically related to the security, among other factors. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the security are compared to the amortized cost basis of the security. If the present value of cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded for the credit loss, limited by the amount that the fair value is less than the amortized cost basis. Any impairment that has not been recorded through an allowance for credit losses is recognized in other comprehensive income. Adjustments to the allowance are reported in our income statement as a component of credit loss expense. Management has made the accounting policy election to exclude accrued interest receivable on available-for-sale securities from the estimate of credit losses. Available-for-sale securities are charged-off against the allowance or, in the absence of any allowance, written down through income when deemed uncollectible by management or when either of the aforementioned criteria regarding intent or requirement to sell is met. Allowance for Credit Losses - Loans. The allowance for credit losses on loans is a contra-asset valuation account, calculated in accordance with ASC 326, that is deducted from the amortized cost basis of loans to present management's best estimate of the net amount expected to be collected. Loans are charged-off against the allowance when deemed uncollectible by management. Expected recoveries do not exceed the aggregate of amounts previously charged-off and expected to be charged-off. Adjustments to the allowance are reported in our income statement as a component of credit loss expense. Management has made the accounting policy election to exclude accrued interest receivable on loans from the estimate of credit losses. Further information regarding our policies and methodology used to estimate the allowance for credit losses on loans is presented in Note 3 - Loans. Allowance For Credit Losses - Off-Balance-Sheet Credit Exposures. The allowance for credit losses on off-balance-sheet credit exposures is a liability account, calculated in accordance with ASC 326, representing expected credit losses over the contractual period for which we are exposed to credit risk resulting from a contractual obligation to extend credit. No allowance is recognized if we have the unconditional right to cancel the obligation. The allowance is reported as a component of accrued interest payable and other liabilities in our consolidated balance sheets. Adjustments to the allowance are reported in our income statement as a component of credit loss expense. Further information regarding our policies and methodology used to estimate the allowance for credit losses on off-balance-sheet credit exposures is presented in Note 7 - Off-Balance-Sheet Arrangements, Commitments, Guarantees and Contingencies. Premises and Equipment. Land is carried at cost. Building and improvements, and furniture and equipment are carried at cost, less accumulated depreciation, computed principally by the straight-line method based on the estimated useful lives of the related property. Leasehold improvements are generally depreciated over the lesser of the term of the respective leases or the estimated useful lives of the improvements. We lease certain office facilities and office equipment under operating leases. We also own certain office facilities which we lease to outside parties under operating lessor leases; however, such leases are not significant. For operating leases other than those considered to be short-term, we recognize lease right-of-use assets and related lease liabilities. Such amounts are reported as components of premises and equipment and accrued interest payable and other liabilities, respectively, on our accompanying consolidated balance sheet. We do not recognize short-term operating leases on our balance sheet. A short-term operating lease has an original term of 12 months or less and does not have a purchase option that is likely to be exercised. In recognizing lease right-of-use assets and related lease liabilities, we account for lease and non-lease components (such as taxes, insurance, and common area maintenance costs) separately as such amounts are generally readily determinable under our lease contracts. Lease payments over the expected term are discounted using our incremental borrowing rate referenced to the Federal Home Loan Bank Secure Connect advance rates for borrowings of similar term. We also consider renewal and termination options in the determination of the term of the lease. If it is reasonably certain that a renewal or termination option will be exercised, the effects of such options are included in the determination of the expected lease term. Generally, we cannot be reasonably certain about whether or not we will renew a lease until such time the lease is within the last two years of the existing lease term. However, renewal options related to our regional headquarters facilities or operations centers are evaluated on a case-by-case basis, typically in advance of such time frame. When we are reasonably certain that a renewal option will be exercised, we measure/remeasure the right-of-use asset and related lease liability using the lease payments specified for the renewal period or, if such amounts are unspecified, we generally assume an increase (evaluated on a case-by-case basis in light of prevailing market conditions) in the lease payment over the final period of the existing lease term. Foreclosed Assets . Assets acquired through or instead of loan foreclosure are held for sale and are initially recorded at fair value less estimated selling costs when acquired, establishing a new cost basis. Write-downs occurring at acquisition are charged against the allowance for credit losses on loans. Foreclosed assets are included in other assets in the accompanying consolidated balance sheets and totaled $14.1 million and $725 thousand at December 31, 2024 and 2023. Regulatory guidelines require us to reevaluate the fair value of foreclosed assets on at least an annual basis. Our policy is to comply with the regulatory guidelines. If the fair value of the asset declines, a write-down is recorded through other non-interest expense along with other expenses related to maintaining the properties. The valuation of foreclosed assets is subjective in nature and may be adjusted in the future because of changes in economic conditions. There were no write-downs of foreclosed assets in 2024, 2023, or 2022. There were no significant concentrations of any properties, to which the aforementioned write-downs relate, in any single geographic region. Revenue Recognition . In general, for revenue not associated with financial instruments, guarantees and lease contracts, we apply the following steps when recognizing revenue from contracts with customers: (i) identify the contract, (ii) identify the performance obligations, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations and (v) recognize revenue when a performance obligation is satisfied. Our contracts with customers are generally short term in nature, typically due within one year or less or cancellable by us or our customer upon a short notice period. Performance obligations for our customer contracts are generally satisfied at a single point in time, typically when the transaction is complete, or over time. For performance obligations satisfied over time, we primarily use the output method, directly measuring the value of the products/services transferred to the customer, to determine when performance obligations have been satisfied. We typically receive payment from customers and recognize revenue concurrent with the satisfaction of our performance obligations. In most cases, this occurs within a single financial reporting period. For payments received in advance of the satisfaction of performance obligations, revenue recognition is deferred until such time as the performance obligations have been satisfied. In cases where we have not received payment despite satisfaction of our performance obligations, we accrue an estimate of the amount due in the period our performance obligations have been satisfied. For contracts with variable components, only amounts for which collection is probable are accrued. We generally act in a principal capacity, on our own behalf, in most of our contracts with customers. In such transactions, we recognize revenue and the related costs to provide our services on a gross basis in our financial statements. In some cases, we act in an agent capacity, deriving revenue through assisting other entities in transactions with our customers. In such transactions, we recognize revenue and the related costs to provide our services on a net basis in our financial statements. These transactions recognized on a net basis primarily relate to insurance and brokerage commissions and fees derived from our customers' use of various interchange and ATM/debit card networks. Share-Based Payments . Compensation expense for stock options, non-vested stock awards/stock units and deferred stock units is based on the fair value of the award on the measurement date, which, for us, is the date of the grant and is recognized ratably over the service period of the award. Compensation expense for performance stock units is based on the fair value of the award on the measurement date, which, for us, is the date of the grant and is recognized over the service period of the award based upon the probable number of units expected to vest. The fair value of stock options is estimated using a binomial lattice-based valuation model. The fair value of non-vested stock awards/stock units and deferred stock units is generally the market price of our stock on the date of grant. The fair value of performance stock units is generally the market price of our stock on the date of grant discounted by the present value of the dividends expected to be paid on our common stock during the service period of the award because dividend equivalent payments on performance stock units are deferred until such time that the units vest and shares are issued. The impact of forfeitures of share-based payment awards on compensation expense is recognized as forfeitures occur. Advertising Costs. Advertising costs are expensed as incurred. Income Taxes . Income tax expense is the total of the current year income tax due or refundable and the change in deferred tax assets and liabilities (excluding deferred tax assets and liabilities related to business combinations or components of other comprehensive income). Deferred tax assets and liabilities are the expected future tax amounts for the temporary differences between carrying amounts and tax bases of assets and liabilities, computed using enacted tax rates. A valuation allowance, if needed, reduces deferred tax assets to the expected amount most likely to be realized. Realization of deferred tax assets is dependent upon the generation of a sufficient level of future taxable income. Although realization is not assured, management believes it is more likely than not that all of the deferred tax assets will be realized. Interest and/or penalties related to income taxes are reported as a component of income tax expense. The income tax effects related to settlements of share-based payment awards are reported in earnings as an increase (or decrease) to income tax expense. See Note 12 - Income Taxes. We file a consolidated income tax return with our subsidiaries. Federal income tax expense or benefit has been allocated to subsidiaries on a separate return basis. Basic and Diluted Earnings Per Common Share. Earnings per common share is computed using the two-class method prescribed under ASC Topic 260, “Earnings Per Share.” ASC 260 provides that unvested share-based payment awards that contain nonforfeitable rights to dividends or dividend equivalents (whether paid or unpaid) are participating securities and shall be included in the computation of earnings per share pursuant to the two-class method. We have determined that our outstanding non-vested stock units and deferred stock units are participating securities. Under the two-class method, basic earnings per common share is computed by dividing net earnings allocated to common stock by the weighted-average number of common shares outstanding during the applicable period, excluding outstanding participating securities. Diluted earnings per common share is computed using the weighted-average number of shares determined for the basic earnings per common share computation plus the dilutive effect of stock compensation using the treasury stock method. A reconciliation of the weighted-average shares used in calculating basic earnings per common share and the weighted average common shares used in calculating diluted earnings per common share for the reported periods is provided in Note 9 - Earnings Per Common Share. Comprehensive Income. Comprehensive income includes all changes in shareholders’ equity during a period, except those resulting from transactions with shareholders. Besides net income, other components of our comprehensive income include the after tax effect of changes in the net unrealized gain/loss on securities available for sale, changes in the net unrealized gain on securities transferred to held to maturity and changes in the net actuarial gain/loss on defined benefit post-retirement benefit plans. See Note 13 - Other Comprehensive Income (Loss). Derivative Financial Instruments . Our hedging policies permit the use of various derivative financial instruments to manage interest rate risk or to hedge specified assets and liabilities. All derivatives are recorded at fair value on our balance sheet. Derivatives executed with the same counterparty are generally subject to master netting arrangements, however, fair value amounts recognized for derivatives and fair value amounts recognized for the right/obligation to reclaim/return cash collateral are not offset for financial reporting purposes. We may be required to recognize certain contracts and commitments as derivatives when the characteristics of those contracts and commitments meet the definition of a derivative. To qualify for hedge accounting, derivatives must be highly effective at reducing the risk associated with the exposure being hedged and must be designated as a hedge at the inception of the derivative contract. While the assessment of hedge effectiveness is foremost based on the objective of our underlying risk management strategies for a particular hedge, we generally consider a hedge to be highly effective if the change in fair value of the derivative hedging instrument is within 80% to 125% of the opposite change in the fair value of the hedged item attributable to the hedged risk. If derivative instruments are designated as hedges of fair values, and such hedges are highly effective, both the change in the fair value of the hedge and the hedged item are included in current earnings. Fair value adjustments related to highly effective cash flow hedges are recorded in other comprehensive income and are reclassified to earnings when the hedged transaction is reflected in earnings. Actual cash receipts and/or payments and related accruals on derivatives related to hedges are recorded as adjustments to the interest income or interest expense associated with the hedged item. During the life of the hedge, we formally assess whether derivatives designated as hedging instruments continue to be highly effective in offsetting changes in the fair value or cash flows of hedged items. If it is determined that a hedge has ceased to be highly effective, we will discontinue hedge accounting prospectively. At such time, previous adjustments to the carrying value of the hedged item are reversed into current earnings and the derivative instrument is reclassified to a trading position recorded at fair value. Fair Value Measurements . In general, fair values of financial instruments are based upon quoted market prices, where available. If such quoted market prices are not available, fair value is based upon internally developed models that primarily use, as inputs, observable market-based parameters. Valuation adjustments may be made to ensure that financial instruments are recorded at fair value. These adjustments may include amounts to reflect counterparty credit quality and our creditworthiness, among other things, as well as unobservable parameters. Any such valuation adjustments are applied consistently over time. See Note 16 - Fair Value Measurements. Transfers of Financial Assets . Transfers of financial assets are accounted for as sales when control over the assets has been surrendered. Control over transferred assets is deemed to be surrendered when (i) the assets have been isolated from us, (ii) the transferee obtains the right (free of conditions that constrain it from taking advantage of that right) to pledge or exchange the transferred assets, and (iii) we do not maintain effective control over the transferred assets through an agreement to repurchase them before their maturity. Loss Contingencies . Loss contingencies, including claims and legal actions arising in the ordinary course of business are recorded as liabilities when the likelihood of loss is probable and an amount or range of loss can be reasonably estimated. Trust Assets. Assets of our trust department, other than cash on deposit at Frost Bank, are not included in the accompanying financial statements because they are not our assets. Accounting Changes, Reclassifications and Restatements.

Securities

Securities	12 Months Ended
	Dec. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Securities	Securities Securities - Held to Maturity. A summary of the amortized cost, fair value and allowance for credit losses related to securities held to maturity as of December 31, 2024 and 2023 is presented below. Amortized Gross Gross Estimated Allowance Net December 31, 2024 Residential mortgage-backed securities $ 1,193,840 $ — $ 71,076 $ 1,122,764 $ — $ 1,193,840 States and political subdivisions 2,338,745 13,954 116,414 2,236,285 (310) 2,338,435 Other 1,500 — 3 1,497 — 1,500 Total $ 3,534,085 $ 13,954 $ 187,493 $ 3,360,546 $ (310) $ 3,533,775 December 31, 2023 Residential mortgage-backed securities $ 1,250,431 $ 76 $ 54,175 $ 1,196,332 $ — $ 1,250,431 States and political subdivisions 2,367,807 42,990 76,540 2,334,257 (310) 2,367,497 Other 1,500 — 45 1,455 — 1,500 Total $ 3,619,738 $ 43,066 $ 130,760 $ 3,532,044 $ (310) $ 3,619,428 All mortgage-backed securities included in the above table were issued by U.S. government agencies and corporations. The carrying value of held-to-maturity securities pledged to secure public funds, trust deposits, repurchase agreements and for other purposes, as required or permitted by law was $1.4 billion and $1.0 billion at December 31, 2024 and 2023, respectively. Accrued interest receivable on held-to-maturity securities totaled $37.8 million and $40.9 million at December 31, 2024 and 2023, respectively and is included in accrued interest receivable and other assets in the accompanying consolidated balance sheets. From time to time, we have reclassified certain securities from available for sale to held to maturity. The net unamortized, unrealized gain remaining on securities transferred in years prior to 2020 included in accumulated other comprehensive income in the accompanying balance sheet totaled $522 thousand ($412 thousand, net of tax) at December 31, 2024 and $1.2 million ($909 thousand, net of tax) at December 31, 2023. This amount will be amortized out of accumulated other comprehensive income over the remaining life of the underlying securities as an adjustment of the yield on those securities. The allowance for credit losses on held-to-maturity securities is a contra-asset valuation account that is deducted from the amortized cost basis of held-to-maturity securities to present the net amount expected to be collected. Management measures expected credit losses on held-to-maturity securities on a collective basis by major security type with each type sharing similar risk characteristics and considers historical credit loss information that is adjusted for current conditions and reasonable and supportable forecasts. With regard to U.S. Treasury and residential mortgage-backed securities issued by the U.S. government, or agencies thereof, it is expected that the securities will not be settled at prices less than the amortized cost bases of the securities as such securities are backed by the full faith and credit of and/or guaranteed by the U.S. government. Accordingly, no allowance for credit losses has been recorded for these securities. With regard to securities issued by States and political subdivisions and other held-to-maturity securities, management considers (i) issuer bond ratings, (ii) historical loss rates for given bond ratings, (iii) whether issuers continue to make timely principal and interest payments under the contractual terms of the securities, (iv) internal forecasts and (v) whether or not such securities are guaranteed by the Texas Permanent School Fund (“PSF”) or pre-refunded by the issuers. The following table summarizes Moody's and/or Standard & Poor's bond ratings for our portfolio of held-to-maturity securities issued by States and political subdivisions and other securities as of December 31, 2024: States and Political Subdivisions Not Guaranteed or Pre-Refunded Guaranteed by the Texas PSF Guaranteed by Third Party Pre-Refunded Total Other Aaa/AAA $ 301,310 $ 1,504,951 $ 13,640 $ 14,531 $ 1,834,432 $ — Aa/AA 498,198 — 6,115 — 504,313 — Not rated — — — — — 1,500 Total $ 799,508 $ 1,504,951 $ 19,755 $ 14,531 $ 2,338,745 $ 1,500 Historical loss rates associated with securities having similar grades as those in our portfolio have generally not been significant. Furthermore, as of December 31, 2024, there were no past due principal or interest payments associated with these securities. The PSF is a sovereign wealth fund which serves to provide revenues for funding of public primary and secondary education in the State of Texas. Based upon (i) the PSF's AAA insurer financial strength rating, (ii) the PSF's substantial capitalization and excess guarantee capacity and (iii) a zero historical loss rate, no allowance for credit losses has been recorded for securities guaranteed by the PSF as there is no current expectation of credit losses related to these securities. Pre-refunded securities have been defeased by the issuer and are fully secured by cash and/or U.S. Treasury securities held in escrow for payment to holders when the underlying call dates of the securities are reached. Accordingly, no allowance for credit losses has been recorded for securities that have been defeased as there is no current expectation of credit losses related to these securities. The following table details activity in the allowance for credit losses on held-to-maturity securities. 2024 2023 2022 Beginning balance $ 310 $ 158 $ 158 Credit loss expense (benefit) — 152 — Ending balance $ 310 $ 310 $ 158 Securities - Available for Sale. A summary of the amortized cost, fair value and allowance for credit losses related to securities available for sale as of December 31, 2024 and 2023 is presented below. Amortized Gross Gross Allowance Estimated December 31, 2024 U.S. Treasury $ 3,692,215 $ — $ 249,895 $ — $ 3,442,320 Residential mortgage-backed securities 8,024,704 2,352 1,029,154 — 6,997,902 States and political subdivisions 4,842,060 2,493 284,329 — 4,560,224 Other 43,179 — — — 43,179 Total $ 16,602,158 $ 4,845 $ 1,563,378 $ — $ 15,043,625 December 31, 2023 U.S. Treasury $ 5,212,894 $ — $ 285,305 $ — $ 4,927,589 Residential mortgage-backed securities 7,463,954 9,066 876,338 — 6,596,682 States and political subdivisions 5,245,721 5,762 240,152 — 5,011,331 Other 42,769 — — — 42,769 Total $ 17,965,338 $ 14,828 $ 1,401,795 $ — $ 16,578,371 All mortgage-backed securities included in the above table were issued by U.S. government agencies and corporations. At December 31, 2024 all of the securities in our available for sale municipal bond portfolio were issued by the State of Texas or political subdivisions or agencies within the State of Texas, of which approximately 70.6% are either guaranteed by the PSF or have been pre-refunded. Securities with limited marketability, such as stock in the Federal Reserve Bank and the Federal Home Loan Bank, are carried at cost and are reported as other available for sale securities in the table above. The carrying value of available-for-sale securities pledged to secure public funds, trust deposits, repurchase agreements and for other purposes, as required or permitted by law was $6.2 billion and $6.1 billion at December 31, 2024 and 2023, respectively. Accrued interest receivable on available-for-sale securities totaled $104.9 million and $114.9 million at December 31, 2024 and 2023, respectively, and is included in accrued interest receivable and other assets in the accompanying consolidated balance sheets. The table below summarizes, as of December 31, 2024, securities available for sale in an unrealized loss position for which an allowance for credit losses has not been recorded, aggregated by type of security and length of time in a continuous unrealized loss position. Less than 12 Months More than 12 Months Total Estimated Unrealized Estimated Unrealized Estimated Unrealized U.S. Treasury $ — $ — $ 3,442,320 $ 249,895 $ 3,442,320 $ 249,895 Residential mortgage-backed securities 1,289,852 26,420 4,725,498 1,002,734 6,015,350 1,029,154 States and political subdivisions 836,599 6,961 3,490,644 277,368 4,327,243 284,329 Total $ 2,126,451 $ 33,381 $ 11,658,462 $ 1,529,997 $ 13,784,913 $ 1,563,378 As of December 31, 2024, no allowance for credit losses has been recognized on available for sale securities in an unrealized loss position as management does not believe any of the securities are impaired due to reasons of credit quality. This is based upon our analysis of the underlying risk characteristics, including credit ratings, and other qualitative factors related to our available for sale securities and in consideration of our historical credit loss experience and internal forecasts. The issuers of these securities continue to make timely principal and interest payments under the contractual terms of the securities. Furthermore, management does not have the intent to sell any of the securities classified as available for sale in the table above and believes that it is more likely than not that we will not have to sell any such securities before a recovery of cost. The unrealized losses are due to increases in market interest rates over the yields available at the time the underlying securities were purchased. The fair value is expected to recover as the securities approach their maturity date or repricing date or if market yields for such investments decline. Contractual Maturities. The following table summarizes the maturity distribution schedule of securities held to maturity and securities available for sale as of December 31, 2024. Mortgage-backed securities are included in maturity categories based on their stated maturity date. Expected maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations. Other securities classified as available for sale include stock in the Federal Reserve Bank and the Federal Home Loan Bank, which have no maturity date. These securities have been included in the total column only. Within 1 Year 1 - 5 Years 5 - 10 Years After 10 Years Total Held To Maturity Amortized Cost Residential mortgage-backed securities $ — $ 510,490 $ 11,244 $ 672,106 $ 1,193,840 States and political subdivisions 7,572 17,702 51,690 2,261,781 2,338,745 Other 1,500 — — — 1,500 Total $ 9,072 $ 528,192 $ 62,934 $ 2,933,887 $ 3,534,085 Estimated Fair Value Residential mortgage-backed securities $ — $ 459,859 $ 9,164 $ 653,741 $ 1,122,764 States and political subdivisions 7,570 17,695 49,489 2,161,531 2,236,285 Other 1,497 — — — 1,497 Total $ 9,067 $ 477,554 $ 58,653 $ 2,815,272 $ 3,360,546 Available For Sale Amortized Cost U. S. Treasury $ 1,096,734 $ 2,204,591 $ 198,105 $ 192,785 $ 3,692,215 Residential mortgage-backed securities 39 869 12,553 8,011,243 8,024,704 States and political subdivisions 284,652 225,414 804,372 3,527,622 4,842,060 Other — — — — 43,179 Total $ 1,381,425 $ 2,430,874 $ 1,015,030 $ 11,731,650 $ 16,602,158 Estimated Fair Value U. S. Treasury $ 1,088,890 $ 2,054,258 $ 165,031 $ 134,141 $ 3,442,320 Residential mortgage-backed securities 39 881 12,588 6,984,394 6,997,902 States and political subdivisions 284,459 222,960 765,004 3,287,801 4,560,224 Other — — — — 43,179 Total $ 1,373,388 $ 2,278,099 $ 942,623 $ 10,406,336 $ 15,043,625 Sales of Securities. Sales of securities available for sale were as follows: 2024 2023 2022 Proceeds from sales $ 123,254 $ 1,904,067 $ — Gross realized gains 426 5,758 — Gross realized losses (522) (5,692) — Tax benefit (expense) related to securities gains/losses 20 (14) — Premiums and Discounts. Premium amortization and discount accretion included in interest income on securities was as follows: 2024 2023 2022 Premium amortization $ (66,257) $ (85,506) $ (110,997) Discount accretion 21,044 21,613 13,597 Net (premium amortization) discount accretion $ (45,213) $ (63,893) $ (97,400) Trading Account Securities. Year-end trading account securities, at estimated fair value, were as follows: 2024 2023 U.S. Treasury $ 33,910 $ 30,265 States and political subdivisions — 1,452 Total $ 33,910 $ 31,717 Net gains and losses on trading account securities included in other non-interest income were as follows: 2024 2023 2022 Net gain on sales transactions $ 4,876 $ 3,843 $ 3,129 Net mark-to-market gains (losses) (109) (33) (230) Net gain on trading account securities $ 4,767 $ 3,810 $ 2,899

Loans

Loans	12 Months Ended
	Dec. 31, 2024
Receivables [Abstract]
Financing Receivables	Loans Year-end loans, including leases net of unearned discounts, consisted of the following: 2024 2023 Commercial and industrial $ 6,109,532 $ 5,967,182 Energy: Production 903,654 681,568 Service 203,629 194,126 Other 21,612 61,043 Total energy 1,128,895 936,737 Commercial real estate: Commercial mortgages 7,165,220 6,746,709 Construction 2,264,076 1,680,724 Land 539,227 555,211 Total commercial real estate 9,968,523 8,982,644 Consumer real estate: Home equity lines of credit 911,239 792,876 Home equity loans 914,738 694,966 Home improvement loans 852,536 765,887 1-4 family mortgage loans 259,456 38,923 Other 165,420 168,074 Total consumer real estate 3,103,389 2,460,726 Total real estate 13,071,912 11,443,370 Consumer and other 444,474 476,962 Total loans $ 20,754,813 $ 18,824,251 Concentrations of Credit. Most of our lending activity occurs within the State of Texas, including the four largest metropolitan areas of Austin, Dallas/Ft. Worth, Houston and San Antonio, as well as other markets. The majority of our loan portfolio consists of commercial and industrial and commercial real estate loans. As of December 31, 2024, the largest industry concentrations were related to the automobile dealerships industry, which totaled 6.0% of total loans and the energy industry, which totaled 5.4% of total loans. Unfunded commitments to extend credit and standby letters of credit issued to customers in the automobile dealership industry totaled $535.5 million and $20.2 million, respectively, as of December 31, 2024, while unfunded commitments to extend credit and standby letters of credit issued to customers in the energy industry totaled $1.0 billion and $62.8 million, respectively, as of December 31, 2024. Foreign Loans. We have U.S. dollar denominated loans and commitments to borrowers in Mexico. The outstanding balance of these loans and the unfunded amounts available under these commitments were not significant at December 31, 2024 or 2023. Overdrafts . Deposit account overdrafts reported as loans totaled $14.6 million and $13.4 million at December 31, 2024 and 2023. Related Party Loans . In the ordinary course of business, we have granted loans to certain directors, executive officers and their affiliates (collectively referred to as “related parties”). Activity in related party loans during 2024 is presented in the following table. Other changes were primarily related to changes in related-party status. Beginning balance $ 416,107 Principal additions 306,414 Principal payments (296,754) Other changes (129,931) Ending balance $ 295,836 Accrued Interest Receivable. Accrued interest receivable on loans totaled $86.8 million and $90.8 million at December 31, 2024 and 2023, respectively and is included in accrued interest receivable and other assets in the accompany consolidated balance sheets. Non-Accrual and Past Due Loans. Loans are considered past due if the required principal and interest payments have not been received as of the date such payments were due. Loans are placed on non-accrual status when, in management’s opinion, the borrower may be unable to meet payment obligations as they become due, as well as when required by regulatory provisions. In determining whether or not a borrower may be unable to meet payment obligations for each class of loans, we consider the borrower’s debt service capacity through the analysis of current financial information, if available, and/or current information with regards to our collateral position. Regulatory provisions would typically require the placement of a loan on non-accrual status if (i) principal or interest has been in default for a period of 90 days or more unless the loan is both well secured and in the process of collection or (ii) full payment of principal and interest is not expected. Loans may be placed on non-accrual status regardless of whether or not such loans are considered past due. When interest accrual is discontinued, all unpaid accrued interest is reversed. Interest income on non-accrual loans is recognized only to the extent that cash payments are received in excess of principal due. A loan may be returned to accrual status when all the principal and interest amounts contractually due are brought current and future principal and interest amounts contractually due are reasonably assured, which is typically evidenced by a sustained period (at least six months) of repayment performance by the borrower. Year-end non-accrual loans, segregated by class of loans, were as follows: December 31, 2024 December 31, 2023 Total Non-Accrual Non-Accrual with No Credit Loss Allowance Total Non-Accrual Non-Accrual with No Credit Loss Allowance Commercial and industrial $ 46,004 $ 8,800 $ 19,545 $ 5,391 Energy 4,079 1,377 11,500 7,398 Commercial real estate: Buildings, land and other 21,920 18,660 22,420 4,983 Construction — — — — Consumer real estate 6,511 4,048 7,442 5,160 Consumer and other 352 — — — Total $ 78,866 $ 32,885 $ 60,907 $ 22,932 The following tables present non-accrual loans as of December 31, 2024 and December 31, 2023 by class and year of origination. December 31, 2024 2024 2023 2022 2021 2020 Prior Revolving Loans Revolving Loans Converted to Term Total Commercial and industrial $ 20,819 $ 2,915 $ 4,053 $ 1,592 $ 335 $ 2,144 $ 1,186 $ 12,960 $ 46,004 Energy — — — — 56 1,321 2,702 — 4,079 Commercial real estate: Buildings, land and other 7,856 2,671 3,233 2,753 1,248 1,505 — 2,654 21,920 Construction — — — — — — — — — Consumer real estate — 47 — — 92 2,202 587 3,583 6,511 Consumer and other — 352 — — — — — — 352 Total $ 28,675 $ 5,985 $ 7,286 $ 4,345 $ 1,731 $ 7,172 $ 4,475 $ 19,197 $ 78,866 December 31, 2023 2023 2022 2021 2020 2019 Prior Revolving Loans Revolving Loans Converted to Term Total Commercial and industrial $ — $ 359 $ 1,635 $ 985 $ 1,257 $ 1,006 $ 9 $ 14,294 $ 19,545 Energy 5,875 — — 56 1,321 — 4,102 146 11,500 Commercial real estate: Buildings, land and other 20,099 — 150 — 1,451 720 — — 22,420 Construction — — — — — — — — — Consumer real estate — — — 38 2,281 483 1,600 3,040 7,442 Consumer and other — — — — — — — — — Total $ 25,974 $ 359 $ 1,785 $ 1,079 $ 6,310 $ 2,209 $ 5,711 $ 17,480 $ 60,907 In the tables above, loans reported as 2024 originations as of December 31, 2024 and loans reported as 2023 originations as of December 31, 2023 were, for the most part, first originated in various years prior to 2024 and 2023, respectively, but were renewed in the respective year. Had non-accrual loans performed in accordance with their original contract terms, we would have recognized additional interest income, net of tax, of approximately $5.7 million in 2024, $4.0 million in 2023 and $1.7 million in 2022. An age analysis of past due loans (including both accruing and non-accruing loans), segregated by class of loans, as of December 31, 2024 is presented in the following table. Loans Loans Total Past Current Total Loans Accruing Commercial and industrial $ 37,130 $ 28,120 $ 65,250 $ 6,044,282 $ 6,109,532 $ 7,685 Energy 4,263 4,079 8,342 1,120,553 1,128,895 — Commercial real estate: Buildings, land and other 37,525 13,040 50,565 7,653,882 7,704,447 1,523 Construction 870 — 870 2,263,206 2,264,076 — Consumer real estate 17,015 12,028 29,043 3,074,346 3,103,389 5,681 Consumer and other 6,693 822 7,515 436,959 444,474 822 Total $ 103,496 $ 58,089 $ 161,585 $ 20,593,228 $ 20,754,813 $ 15,711 Modifications to Borrowers Experiencing Financial Difficulty. From time to time, we may modify certain loans to borrowers who are experiencing financial difficulty. In some cases, these modifications may result in new loans. Loan modifications to borrowers experiencing financial difficulty may be in the form of a principal forgiveness, an interest rate reduction, an other-than-insignificant payment delay, a term extension, or a combination thereof, among other things. The period-end balance of loan modifications, segregated by type of modification, to borrowers experiencing financial difficulty during 2024 and 2023 are set forth in the table below, regardless of whether such modifications resulted in a new loan. There were $44.1 million in commitments to lend additional funds to these borrowers at December 31, 2024. Payment Percent of Combination: Payment Delay and Term Extension Percent of Interest Rate Reduction Percent of December 31, 2024 Commercial and industrial $ 6,126 0.1 % $ 45,835 0.8 % $ — — % Commercial real estate: Buildings, land, and other 2,012 — — — 31,302 0.4 $ 8,138 — $ 45,835 0.2 $ 31,302 0.2 Payment Percent of Combination: Payment Delay and Term Extension Percent of Combination: Interest Rate Reduction and Term Extension Percent of December 31, 2023 Commercial and industrial $ — — $ 13,813 0.2 $ — — Commercial real estate: Buildings, land, and other — — 19,438 0.3 2,092 — $ — — $ 33,251 0.2 $ 2,092 — During 2024, we modified the interest rate on one loan from a variable rate of prime plus a spread of 0.50% (8.50% as of the modification date) to a variable rate of prime minus a spread of 1.50% (6.50% after modification) with a floor of 6.00%. During 2023, we modified the interest rate on one loan from a variable rate of prime plus a spread of 1.75% (10.25% as of the modification date) to a fixed rate of 6.74% in addition to extending the term of the loan. The financial effects of the other loan modifications made to borrowers experiencing financial difficulty during 2024 and 2023 were not significant. The loan modifications reported in the table above did not significantly impact our determination of the allowance for credit losses on loans during 2024 or 2023. Information as of or for the years ended December 31, 2024, 2023, or 2022 related to loans modified (by type of modification) in the preceding twelve months, respectively, whereby the borrower was experiencing financial difficulty at the time of modification is set forth in the following table. Payment Combination: Payment Delay and Term Extension 2024 Past due in excess of 90 days or on non-accrual status at period-end: Commercial and industrial $ 1,693 $ — Commercial real estate: Buildings, land, and other 2,012 — $ 3,705 $ — 2023 Past due in excess of 90 days or on non-accrual status at period-end: Commercial and industrial $ — $ 13,813 Commercial real estate: Buildings, land, and other — 19,438 $ — $ 33,251 2022 Past due in excess of 90 days or on non-accrual status at period-end: Commercial real estate: Buildings, land, and other $ 1,051 $ — $ 1,051 $ — Charge-offs during the period: Commercial real estate: Buildings, land, and other $ 371 $ 352 $ 371 $ 352 Proceeds from sales: Commercial real estate: Buildings, land, and other $ — $ 1,070 $ — $ 1,070 Credit Quality Indicators. As part of the on-going monitoring of the credit quality of our loan portfolio, management tracks certain credit quality indicators including trends related to (i) the weighted-average risk grade of commercial loans, (ii) the level of classified commercial loans, (iii) the delinquency status of consumer loans (iv) non-performing loans (see details above) and (vi) the general economic conditions in the State of Texas. We utilize a risk grading matrix to assign a risk grade to each of our commercial loans. Loans are graded on a scale of 1 to 14. A description of the general characteristics of the 14 risk grades is as follows: • Grades 1, 2 and 3 - These grades include loans to very high credit quality borrowers of investment or near investment grade. These borrowers are generally publicly traded (grades 1 and 2), have significant capital strength, moderate leverage, stable earnings and growth, and readily available financing alternatives. Smaller entities, regardless of strength, would generally not fit in these grades. • Grades 4 and 5 - These grades include loans to borrowers of solid credit quality with moderate risk. Borrowers in these grades are differentiated from higher grades on the basis of size (capital and/or revenue), leverage, asset quality and the stability of the industry or market area. • Grades 6, 7 and 8 - These grades include “pass grade” loans to borrowers of acceptable credit quality and risk. Such borrowers are differentiated from Grades 4 and 5 in terms of size, secondary sources of repayment or they are of lesser stature in other key credit metrics in that they may be over-leveraged, undercapitalized, inconsistent in performance or in an industry or an economic area that is known to have a higher level of risk, volatility, or susceptibility to weaknesses in the economy. • Grade 9 - This grade includes loans on management’s “watch list” and is intended to be utilized on a temporary basis for pass grade borrowers where a significant risk-modifying action is anticipated in the near term. • Grade 10 - This grade is for “Other Assets Especially Mentioned” in accordance with regulatory guidelines. This grade is intended to be temporary and includes loans to borrowers whose credit quality has clearly deteriorated and are at risk of further decline unless active measures are taken to correct the situation. • Grade 11 - This grade includes “Substandard” loans, in accordance with regulatory guidelines, for which the accrual of interest has not been stopped. By definition under regulatory guidelines, a “Substandard” loan has defined weaknesses which make payment default or principal exposure likely, but not yet certain. Such loans are apt to be dependent upon collateral liquidation, a secondary source of repayment or an event outside of the normal course of business. • Grade 12 - This grade includes “Substandard” loans, in accordance with regulatory guidelines, for which the accrual of interest has been stopped. This grade includes loans where interest is more than 120 days past due and not fully secured and loans where a specific valuation allowance may be necessary, but generally does not exceed 30% of the principal balance. • Grade 13 - This grade includes “Doubtful” loans in accordance with regulatory guidelines. Such loans are placed on non-accrual status and may be dependent upon collateral having a value that is difficult to determine or upon some near-term event which lacks certainty. Additionally, these loans generally have a specific valuation allowance in excess of 30% of the principal balance. • Grade 14 - This grade includes “Loss” loans in accordance with regulatory guidelines. Such loans are to be charged-off or charged-down when payment is acknowledged to be uncertain or when the timing or value of payments cannot be determined. “Loss” is not intended to imply that the loan or some portion of it will never be paid, nor does it in any way imply that there has been a forgiveness of debt. In monitoring credit quality trends in the context of assessing the appropriate level of the allowance for credit losses on loans, we monitor portfolio credit quality by the weighted-average risk grade of each class of commercial loan. Individual relationship managers, under the oversight of credit administration, review updated financial information for all pass grade loans to reassess the risk grade on at least an annual basis. When a loan has a risk grade of 9, it is still considered a pass grade loan; however, it is considered to be on management’s “watch list,” where a significant risk-modifying action is anticipated in the near term. When a loan has a risk grade of 10 or higher, a special assets officer monitors the loan on an on-going basis. The following tables present weighted-average risk grades for all commercial loans, by class and year of origination/renewal as of December 31, 2024 and 2023. December 31, 2024 2024 2023 2022 2021 2020 Prior Revolving Loans Revolving Loans Converted to Term Total Commercial and industrial Risk grades 1-8 $ 1,553,200 $ 513,073 $ 385,824 $ 257,280 $ 298,912 $ 253,018 $ 2,242,193 $ 50,257 $ 5,553,757 Risk grade 9 15,552 24,059 58,521 25,818 3,796 9,959 109,594 15,147 262,446 Risk grade 10 4,992 9,269 42,146 2,112 918 12,290 15,332 1,876 88,935 Risk grade 11 35,583 18,057 17,673 2,987 4,675 2,092 44,926 32,397 158,390 Risk grade 12 13,107 2,443 2,574 1,564 324 2,144 1,179 9,404 32,739 Risk grade 13 7,712 472 1,479 28 11 — 7 3,556 13,265 $ 1,630,146 $ 567,373 $ 508,217 $ 289,789 $ 308,636 $ 279,503 $ 2,413,231 $ 112,637 $ 6,109,532 W/A risk grade 6.73 7.12 7.52 7.13 5.58 6.11 6.30 9.12 6.64 Energy Risk grades 1-8 $ 387,904 $ 22,510 $ 35,357 $ 16,150 $ 1,516 $ 2,648 $ 639,362 $ 5,872 $ 1,111,319 Risk grade 9 — 1,677 662 2,011 — 398 5,035 1,400 11,183 Risk grade 10 — — 52 — — — — — 52 Risk grade 11 188 — 2,038 — 36 — — — 2,262 Risk grade 12 — — — — 56 1,321 2 — 1,379 Risk grade 13 — — — — — — 2,700 — 2,700 $ 388,092 $ 24,187 $ 38,109 $ 18,161 $ 1,608 $ 4,367 $ 647,099 $ 7,272 $ 1,128,895 W/A risk grade 6.16 7.14 7.53 4.75 6.47 8.97 5.05 7.31 5.58 Commercial real estate: Buildings, land, other Risk grades 1-8 $ 1,427,212 $ 1,288,934 $ 1,450,649 $ 1,006,922 $ 668,316 $ 965,448 $ 204,577 $ 91,444 $ 7,103,502 Risk grade 9 9,347 18,408 56,419 72,096 11,197 35,661 4,968 3,718 211,814 Risk grade 10 570 31,596 64,063 55,512 10,546 10,746 — — 173,033 Risk grade 11 5,764 5,739 63,772 23,594 13,027 82,282 — — 194,178 Risk grade 12 7,856 2,671 3,233 2,531 1,126 1,505 — 2,373 21,295 Risk grade 13 — — — 222 122 — — 281 625 $ 1,450,749 $ 1,347,348 $ 1,638,136 $ 1,160,877 $ 704,334 $ 1,095,642 $ 209,545 $ 97,816 $ 7,704,447 W/A risk grade 7.16 7.32 7.39 7.52 7.05 7.17 6.01 6.80 7.25 Construction Risk grades 1-8 $ 615,683 $ 601,151 $ 427,984 $ 59,895 $ 2,727 $ 559 $ 151,846 $ 159 $ 1,860,004 Risk grade 9 46,456 9,283 65,590 35,006 — — 15,276 — 171,611 Risk grade 10 107,666 — 48,001 76,794 — — — — 232,461 Risk grade 11 — — — — — — — — — Risk grade 12 — — — — — — — — — Risk grade 13 — — — — — — — — — $ 769,805 $ 610,434 $ 541,575 $ 171,695 $ 2,727 $ 559 $ 167,122 $ 159 $ 2,264,076 W/A risk grade 7.82 7.35 7.99 8.85 7.39 7.65 6.46 6.98 7.71 Total commercial real estate $ 2,220,554 $ 1,957,782 $ 2,179,711 $ 1,332,572 $ 707,061 $ 1,096,201 $ 376,667 $ 97,975 $ 9,968,523 W/A risk grade 7.39 7.33 7.54 7.69 7.06 7.17 6.21 6.80 7.35 December 31, 2023 2023 2022 2021 2020 2019 Prior Revolving Loans Revolving Loans Converted to Term Total Commercial and industrial Risk grades 1-8 $ 1,489,026 $ 706,210 $ 458,855 $ 349,744 $ 172,656 $ 206,643 $ 2,083,490 $ 41,254 $ 5,507,878 Risk grade 9 57,625 42,618 12,258 4,952 1,641 10,383 70,142 5,625 205,244 Risk grade 10 63,205 2,222 1,307 911 4,005 581 35,977 1,046 109,254 Risk grade 11 9,450 16,837 25,932 7,854 2,530 1,153 58,134 3,371 125,261 Risk grade 12 — 359 1,635 950 1,257 1,006 1 11,894 17,102 Risk grade 13 — — — 35 — — 8 2,400 2,443 $ 1,619,306 $ 768,246 $ 499,987 $ 364,446 $ 182,089 $ 219,766 $ 2,247,752 $ 65,590 $ 5,967,182 W/A risk grade 6.53 7.05 7.26 5.87 6.01 6.04 6.50 8.48 6.60 Energy Risk grades 1-8 $ 270,710 $ 54,185 $ 75,004 $ 3,673 $ 1,819 $ 4,047 $ 451,897 $ 9,886 $ 871,221 Risk grade 9 1,137 7,315 1,041 — 456 — 17,680 14 27,643 Risk grade 10 — — 33 — 291 494 — — 818 Risk grade 11 — — 25 106 2,989 — 21,650 785 25,555 Risk grade 12 5,875 — — 56 1,321 — 1,402 146 8,800 Risk grade 13 — — — — — — 2,700 — 2,700 $ 277,722 $ 61,500 $ 76,103 $ 3,835 $ 6,876 $ 4,541 $ 495,329 $ 10,831 $ 936,737 W/A risk grade 6.19 7.07 6.00 6.99 10.02 7.07 5.75 7.33 6.05 Commercial real estate: Buildings, land, other Risk grades 1-8 $ 1,601,175 $ 1,667,750 $ 1,186,559 $ 747,289 $ 503,303 $ 874,942 $ 214,874 $ 99,466 $ 6,895,358 Risk grade 9 12,173 68,007 28,870 13,250 16,272 23,214 11,143 541 173,470 Risk grade 10 7,671 29,278 17,364 34,672 747 3,153 3,716 — 96,601 Risk grade 11 4,105 20,589 20,119 16,363 793 51,739 — 363 114,071 Risk grade 12 17,449 — 150 — 1,451 720 — — 19,770 Risk grade 13 2,650 — — — — — — — 2,650 $ 1,645,223 $ 1,785,624 $ 1,253,062 $ 811,574 $ 522,566 $ 953,768 $ 229,733 $ 100,370 $ 7,301,920 W/A risk grade 7.23 7.18 7.29 7.22 6.90 7.16 7.49 6.77 7.20 Construction Risk grades 1-8 $ 538,072 $ 537,705 $ 264,770 $ 28,063 $ 296 $ 1,613 $ 155,567 $ — $ 1,526,086 Risk grade 9 3,414 35,565 79,871 — — — 8,252 — 127,102 Risk grade 10 13,322 — — — — — 3,713 — 17,035 Risk grade 11 5,912 3,104 — — — — 1,485 — 10,501 Risk grade 12 — — — — — — — — — Risk grade 13 — — — — — — — — — $ 560,720 $ 576,374 $ 344,641 $ 28,063 $ 296 $ 1,613 $ 169,017 $ — $ 1,680,724 W/A risk grade 7.44 7.44 7.93 2.55 7.22 6.78 7.34 — 7.45 Total commercial real estate $ 2,205,943 $ 2,361,998 $ 1,597,703 $ 839,637 $ 522,862 $ 955,381 $ 398,750 $ 100,370 $ 8,982,644 W/A risk grade 7.28 7.24 7.43 7.07 6.90 7.15 7.43 6.77 7.24 At December 31, 2024 and 2023, the weighted-average risk grades for “pass grade” (risk grades 1-8) loans were 6.30 and 6.32, respectively, for commercial and industrial; 5.51 and 5.73, respectively, for energy; 7.01 and 7.03, respectively, for commercial real estate - buildings, land and other; and 7.31 and 7.27, respectively, for commercial real estate - construction. Furthermore, in the tables above, there are loans reported as 2024 originations as of December 31, 2024 and 2023 originations as of December 31, 2023 that have risk grades of 11 or higher. These loans were, for the most part, first originated in various years prior to 2024 and 2023, respectively, but were renewed in the respective year. Information about the payment status of consumer loans, segregated by portfolio segment and year of origination, as of December 31, 2024 and December 31, 2023 was as follows: December 31, 2024 2024 2023 2022 2021 2020 Prior Revolving Loans Revolving Loans Converted to Term Total Consumer real estate: Past due 30-89 days $ 632 $ 1,030 $ 1,897 $ 965 $ 645 $ 1,944 $ 9,790 $ 112 $ 17,015 Past due 90 or more days — 292 972 1,165 213 3,255 2,452 3,679 12,028 Total past due 632 1,322 2,869 2,130 858 5,199 12,242 3,791 29,043 Current loans 699,196 544,811 387,344 248,225 146,972 152,517 886,848 8,433 3,074,346 Total $ 699,828 $ 546,133 $ 390,213 $ 250,355 $ 147,830 $ 157,716 $ 899,090 $ 12,224 $ 3,103,389 Consumer and other: Past due 30-89 days $ 3,378 $ 772 $ 249 $ 22 $ 66 $ 23 $ 1,734 $ 449 $ 6,693 Past due 90 or more days 243 — — — — 3 395 181 822 Total past due 3,621 772 249 22 66 26 2,129 630 7,515 Current loans 54,440 27,705 9,276 3,006 1,906 1,124 315,038 24,464 436,959 Total $ 58,061 $ 28,477 $ 9,525 $ 3,028 $ 1,972 $ 1,150 $ 317,167 $ 25,094 $ 444,474 December 31, 2023 2023 2022 2021 2020 2019 Prior Revolving Loans Revolving Loans Converted to Term Total Consumer real estate: Past due 30-89 days $ 874 $ 2,066 $ 1,318 $ 959 $ 537 $ 2,641 $ 3,570 $ 539 $ 12,504 Past due 90 or more days — 512 626 38 — 887 2,566 3,087 7,716 Total past due 874 2,578 1,944 997 537 3,528 6,136 3,626 20,220 Current loans 579,505 432,719 281,820 170,225 58,744 134,319 775,465 7,709 2,440,506 Total $ 580,379 $ 435,297 $ 283,764 $ 171,222 $ 59,281 $ 137,847 $ 781,601 $ 11,335 $ 2,460,726 Consumer and other: Past due 30-89 days $ 3,014 $ 488 $ 148 $ 66 $ 28 $ 40 $ 2,553 $ 158 $ 6,495 Past due 90 or more days 153 — 27 — 20 — 51 — 251 Total past due 3,167 488 175 66 48 40 2,604 158 6,746 Current loans 67,272 28,885 6,290 3,581 1,199 1,230 339,789 21,970 470,216 Total $ 70,439 $ 29,373 $ 6,465 $ 3,647 $ 1,247 $ 1,270 $ 342,393 $ 22,128 $ 476,962 Revolving loans that converted to term during 2024 and 2023 were as follows: 2024 2023 Commercial and industrial $ 71,275 $ 28,713 Energy 2,393 6,409 Commercial real estate: Buildings, land and other 9,776 4,780 Construction 159 — Consumer real estate 3,425 2,467 Consumer and other 11,158 7,482 Total $ 98,186 $ 49,851 In assessing the general economic conditions in the State of Texas, management monitors and tracks the Texas Leading Index (“TLI”), which is produced by the Federal Reserve Bank of Dallas. The TLI is a single summary statistic that is designed to signal the likelihood of the Texas economy’s transition from expansion to recession and vice versa. Management believes this index provides a reliable indication of the direction of overall credit quality. The TLI is a composite of the following eight leading indicators: (i) Texas Value of the Dollar, (ii) U.S. Leading Index, (iii) real oil prices (iv) well permits, (v) initial claims for unemployment insurance, (vi) Texas Stock Index, (vii) Help-Wanted Index and (viii) average weekly hours worked in manufacturing. The TLI totaled 125.9 at December 31, 2024 and 127.2 at December 31, 2023. A lower TLI value implies less favorable economic conditions. Allowance For Credit Losses - Loans. The allowance for credit losses on loans is a contra-asset valuation account, calculated in accordance with ASC 326, that is deducted from the amortized cost basis of loans to present the net amount expected to be collected. The amount of the allowance represents management's best estimate of current expected credit losses on loans considering available information, from internal and external sources, relevant to assessing collectibility over the loans' contractual terms, adjusted for expected prepayments when appropriate. The contractual term excludes expected extensions, renewals and modifications unless (i) management has a reasonable expectation that a loan to an individual borrower that is experiencing financial difficulty will be modified or (ii) such extension or renewal options are not unconditionally cancellable by us and, in such cases, the borrower is likely to meet applicable conditions and likely to request extension or renewal. Relevant available information includes historical credit loss experience; current conditions; and reasonable and supportable forecasts. While historical credit loss experience provides the basis for the estimation of expected credit losses, adjustments to historical loss information may be made for differences in current portfolio-specific risk characteristics, environmental conditions, or other relevant factors. The allowance for credit losses is measured on a collective basis for portfolios of loans when similar risk characteristics exist. Loans that do not share risk characteristics are evaluated for expected credit losses on an individual basis and excluded from the collective evaluation. Expected credit losses for collateral dependent loans, including loans where the borrower is experiencing financial difficulty but foreclosure is not probable, are based on the fair value of the collateral at the reporting date, adjusted for selling costs as appropriate. Credit loss expense related to loans reflects the totality of actions taken on all loans for a particular period including any necessary increases or decreases in the allowance related to changes in credit loss expectations associated with specific loans or pools of loans. Portions of the allowance may be allocated for specific credits; however, the entire allowance is available for any credit that, in management’s judgment, should be charged off. While management utilizes its best judgment and information available, the ultimate appropriateness of the allowance is dependent upon a variety of factors beyond our control, including the performance of our loan portfolio, the economy, changes in interest rates and the view of the regulatory authorities toward loan classifications. In calculating the allowance for credit losses, most loans are segmented into pools based upon similar characteristics and risk profiles. Common characteristics and risk profiles include the type/purpose of loan, underlying collateral, geographical similarity, and historical/expected credit loss patterns. In developing these loan pools for the purposes of modeling expected credit losses, we also analyzed the degree of correlation in how loans within each portfolio respond when subjected to varying economic conditions and scenarios as well as other portfolio stress factors. For modeling purposes, our loan pools include (i) commercial and industrial non-revolving, (ii) commercial and industrial revolving, (iii) energy, (iv) commercial real estate - owner occupied, (v) commercial real estate - non-owner occupied, (vi) commercial real estate - construction/land development, (vii) consumer real estate and (viii) consumer and other. Prior to 2023, energy loans were included within the commercial and industrial loan pools. See discussion of the 2023 model updates below. We periodically reassess each pool to ensure the loans within the pool continue to share similar characteristics and risk profiles and to determine whether further segmentation is necessary. For each loan pool, we measure expected credit losses over the life of each loan utilizing a combination of models which measure (i) probability of default (“PD”), which is the likelihood that loan will stop performing/default, (ii) probability of attrition (“PA”), which is the likelihood that a loan will pay-off prior to maturity, (iii) loss given default (“LGD”), which is the expected loss rate for loans in default and (iv) exposure at default (“EAD”), which is the estimated outstanding principal balance of the loans upon default, including the expected funding of unfunded commitments outstanding as of the measurement date. For commercial loan portfolios, the PD is calculated using a transition matrix to determine the likelihood of a customer’s risk grade migrating from one specified range of risk grades to a different specified range. Expected credit losses are calculated as the product of PD (adjusted for attrition), LGD and EAD. This methodology builds on default probabilities already incorporated into our risk grading process by utilizing pool-specific historical loss rates to calculate expected credit losses. These pool-specific historical loss rates may be adjusted for current macroeconomic assumptions, as further discussed below, and other factors such as differences in underwriting standards, portfolio mix, or when historical asset terms do not reflect the contractual terms of the financial assets being evaluated as of the measurement date. Each time we measure expected credit losses, we assess the relevancy of historical loss information and consider any necessary adjustments to address any differences in asset-specific characteristics. Due to their short-term nature, expected credit losses for overdrafts included in consumer and other loans are based solely upon a weighting of recent historical charge-offs over a period of three years. The measurement of expected credit losses is impacted by loan/borrower attributes and certain macroeconomic variables. Significant loan/borrower attributes utilized in our modeling processes include, among other things, (i) origination date, (ii) maturity date, (iii) payment type, (iv) collateral type and amount, (v) current risk grade, (vi) current unpaid balance and commitment utilization rate, (vii) payment status/delinquency history and (viii) expected recoveries of previously charged-off amounts. Significant macroeconomic variables utilized in our modeling processes include, among other things, (i) Gross State Product for Texas and U.S. Gross Domestic Product, (ii) selected market interest rates including U.S. Treasury rates, bank prime rate, 30-year fixed mortgage rate, BBB corporate bond rate, among others, (iii) unemployment rates, (iv) commercial and residential property prices in Texas and the U.S. as a whole, (v) West Texas Intermediate crude oil price and (vi) total stock market index. PD and PA were estimated by analyzing internally-sourced data related to historical performance of each loan pool over a complete economic cycle. PD and PA are adjusted to reflect the current impact of certain macroeconomic variables as well as their expected changes over a reasonable and supportable forecast period. We have determined that we are reasonably able to forecast the macroeconomic variables used in our modeling processes with an acceptable degree of confidence for a total of two years with the last twelve months of the forecast period encompassing a reversion process whereby the forecasted macroeconomic variables are reverted to their historical mean utilizing a rational, systematic basis. The macroeconomic variables utilized as inputs in our modeling processes were subjected to a variety of analysis procedures and were selected primarily based on statistical relevancy and correlation to our historical credit losses. By reverting these modeling inputs to their historical mean and considering loan/borrower specific attributes, our models are intended to yield a measurement of expected credit losses that reflects our average historical loss rates for periods subsequent to the twelve-month reversion period. The LGD is based on historical recovery averages for each loan pool, adjusted to reflect the current impact of certain macroeconomic variables as well as their ex

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2024
Property, Plant and Equipment [Abstract]
Premises and Equipment	Premises and Equipment and Lease Commitments Year-end premises and equipment were as follows: 2024 2023 Land $ 224,290 $ 191,594 Buildings 644,240 581,745 Technology, furniture and equipment 281,697 262,666 Leasehold improvements 250,572 230,642 Construction and projects in progress 24,135 36,910 Lease right-of-use assets 270,282 280,502 1,695,216 1,584,059 Less accumulated depreciation and amortization (449,839) (394,026) Total premises and equipment, net $ 1,245,377 $ 1,190,033 Depreciation of premises and equipment totaled $61.9 million in 2024, $60.6 million 2023 and $57.4 million in 2022. Lease Commitments . We lease certain office facilities and office equipment under operating leases. Rent expense for all operating leases totaled $49.7 million in 2024, $50.5 million in 2023 and $47.7 million in 2022. The components of total lease expense in 2024 and 2023 were as follows: 2024 2023 Amortization of lease right-of-use assets $ 35,400 $ 34,137 Short-term lease expense 1,456 2,576 Non-lease components (including taxes, insurance, common maintenance, etc.) 12,835 13,811 Total $ 49,691 $ 50,524 Right-of-use lease assets totaled $270.3 million and $280.5 million at December 31, 2024 and 2023, respectively, and are reported as a component of premises and equipment on our accompanying consolidated balance sheets. The related lease liabilities totaled $308.1 million and $316.4 million at December 31, 2024 and 2023, respectively, and are reported as a component of accrued interest payable and other liabilities in the accompanying consolidated balance sheets. Lease payments under operating leases that were applied to our operating lease liability totaled $33.7 million during 2024 and $32.1 million during 2023. The following table reconciles future undiscounted lease payments due under non-cancelable operating leases (those amounts subject to recognition) to the aggregate operating lessee lease liability as of December 31, 2024: Future lease payments: 2025 $ 36,953 2026 37,007 2027 35,958 2028 34,007 2029 29,795 Thereafter 206,868 Total undiscounted operating lease liability 380,588 Imputed interest 72,535 Total operating lease liability included in the accompanying balance sheet $ 308,053 Weighted-average lease term in years 12.39 Weighted-average discount rate 3.39%

Deposits

Deposits	12 Months Ended
	Dec. 31, 2024
Deposits [Abstract]
Deposits	Deposits Year-end deposits were as follows: 2024 2023 Non-interest-bearing demand deposits $ 14,441,820 $ 14,926,094 Interest-bearing deposits: Savings and interest checking 10,310,942 10,512,637 Money market accounts 11,568,254 10,997,279 Time accounts 6,401,732 5,484,558 Total interest-bearing deposits 28,280,928 26,994,474 Total deposits $ 42,722,748 $ 41,920,568 The following table presents additional information about our year-end deposits: 2024 2023 Deposits from foreign sources (primarily Mexico) $ 1,219,463 $ 1,061,701 Non-interest-bearing public funds deposits 759,819 675,016 Interest-bearing public funds deposits 625,104 630,455 Total deposits not covered by deposit insurance 22,972,618 22,393,786 Time deposits not covered by deposit insurance 2,744,112 2,339,716 Deposits from certain directors, executive officers and their affiliates 121,113 115,798 Scheduled maturities of time deposits at December 31, 2024 were as follows: 2025 $ 6,214,390 2026 17,636 2027 169,706 $ 6,401,732 Scheduled maturities of time deposits not covered by deposit insurance at December 31, 2024, were as follows: Due within 3 months or less $ 2,500,536 Due after 3 months and within 6 months 91,140 Due after 6 months and within 12 months 107,808 Due after 12 months 44,628 $ 2,744,112

Borrowed Funds

Borrowed Funds	12 Months Ended
	Dec. 31, 2024
Debt Disclosure [Abstract]
Borrowed Funds	Borrowed Funds Federal Funds Purchased and Securities Sold Under Agreements to Repurchase. Federal funds purchased are short-term borrowings that typically mature within one ninety thirty ninety Subordinated Notes. In March 2017, we issued $100 million of 4.50% subordinated notes that mature on March 17, 2027. The notes, which qualify as Tier 2 capital for Cullen/Frost, bear interest at the rate of 4.50% per annum, payable semi-annually on each March 17 and September 17. The notes are unsecured and subordinated in right of payment to the payment of our existing and future senior indebtedness and structurally subordinated to all existing and future indebtedness of our subsidiaries. Unamortized debt issuance costs related to these notes, totaled approximately $352 thousand and $509 thousand December 31, 2024 and 2023. Proceeds from sale of the notes were used for general corporate purposes. Junior Subordinated Deferrable Interest Debentures. At December 31, 2024 and 2023, we had $123.7 million of junior subordinated deferrable interest debentures issued to Cullen/Frost Capital Trust II (“Trust II”), a wholly owned Delaware statutory business trust. Unamortized debt issuance costs related to Trust II totaled $528 thousand and $585 thousand at December 31, 2024 and 2023. Trust II is a variable interest entity for which we are not the primary beneficiary and, as such, its accounts are not included in our consolidated financial statements. See Note 1 - Summary of Significant Accounting Policies for additional information about our consolidation policy. Details of our transactions with the capital trust are presented below. Trust II was formed in 2004 for the purpose of issuing $120.0 million of floating rate (three-month term Secured Overnight Funding Rate “SOFR” plus a margin of approximately 1.81%) trust preferred securities, which represent beneficial interests in the assets of the trust. The trust preferred securities will mature on March 1, 2034 and are currently redeemable with the approval of the Federal Reserve Board in whole or in part at our option. Distributions on the trust preferred securities are payable quarterly in arrears on March 1, June 1, September 1 and December 1 of each year. Trust II also issued $3.7 million of common equity securities to Cullen/Frost. The proceeds of the offering of the trust preferred securities and common equity securities were used to purchase $123.7 million of floating rate (three-month term SOFR plus a margin of approximately 1.81%, which was equal to 6.28% and 7.19% at December 31, 2024 and 2023, respectively) junior subordinated deferrable interest debentures issued by us, which have terms substantially similar to the trust preferred securities. We have the right at any time during the term of the debentures issued to Trust II to defer payments of interest at any time or from time to time for an extension period not exceeding 20 consecutive quarterly periods with respect to each extension period. Under the terms of the debentures, in the event that under certain circumstances there is an event of default under the debentures or we have elected to defer interest on the debentures, we may not, with certain exceptions, declare or pay any dividends or distributions on our capital stock or purchase or acquire any of our capital stock. Payments of distributions on the trust preferred securities and payments on redemption of the trust preferred securities are guaranteed by us on a limited basis. We are obligated by agreement to pay any costs, expenses or liabilities of Trust II other than those arising under the trust preferred securities. Our obligations under the junior subordinated debentures, the related indenture, the trust agreement establishing the trust, the guarantee and the agreement as to expenses and liabilities, in the aggregate, constitute a full and unconditional guarantee by us of Trust II’s obligations under the trust preferred securities. Although the accounts of Trust II are not included in our consolidated financial statements, the trust preferred securities issued by Trust II are included in the capital of Cullen/Frost for regulatory capital purposes. See Note 8 - Capital and Regulatory Matters.

Off-Balance-Sheet Arrangements,

Off-Balance-Sheet Arrangements, Commitments, Guarantees and Contingencies	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Off-Balance-Sheet Arrangements, Commitments, Guarantees and Contingencies	Off-Balance-Sheet Arrangements, Commitments, Guarantees and Contingencies Financial Instruments with Off-Balance-Sheet Risk . In the normal course of business, we enter into various transactions, which, in accordance with generally accepted accounting principles in the United States, are not included in our consolidated balance sheets. We enter into these transactions to meet the financing needs of our customers. These transactions include commitments to extend credit and standby letters of credit, which involve, to varying degrees, elements of credit risk and interest rate risk in excess of the amounts recognized in the consolidated balance sheets. We minimize our exposure to loss under these commitments by subjecting them to credit approval and monitoring procedures. We enter into contractual commitments to extend credit, normally with fixed expiration dates or termination clauses, at specified rates and for specific purposes. Substantially all of our commitments to extend credit are contingent upon customers maintaining specific credit standards at the time of loan funding. Standby letters of credit are written conditional commitments issued by us to guarantee the performance of a customer to a third party. In the event the customer does not perform in accordance with the terms of the agreement with the third party, we would be required to fund the commitment. The maximum potential amount of future payments we could be required to make is represented by the contractual amount of the commitment. If the commitment were funded, we would be entitled to seek recovery from the customer. Our policies generally require that standby letter of credit arrangements contain security and debt covenants similar to those contained in loan agreements. We consider the fees collected in connection with the issuance of standby letters of credit to be representative of the fair value of our obligation undertaken in issuing the guarantee. In accordance with applicable accounting standards related to guarantees, we defer fees collected in connection with the issuance of standby letters of credit. The fees are then recognized in income proportionately over the life of the standby letter of credit agreement. The deferred standby letter of credit fees represent the fair value of our potential obligations under the standby letter of credit guarantees. Year-end financial instruments with off-balance-sheet risk are presented in the following table. Commitments and standby letters of credit are presented at contractual amounts; however, since many of these commitments are expected to expire unused or only partially used, the total amounts of these commitments do not necessarily reflect future cash requirements. 2024 2023 Commitments to extend credit $ 12,046,520 $ 12,195,073 Standby letters of credit 449,176 438,635 Deferred standby letter of credit fees 3,071 2,912 Allowance For Credit Losses - Off-Balance-Sheet Credit Exposures. The allowance for credit losses on off-balance-sheet credit exposures is a liability account, calculated in accordance with ASC 326, representing expected credit losses over the contractual period for which we are exposed to credit risk resulting from a contractual obligation to extend credit. No allowance is recognized if we have the unconditional right to cancel the obligation. Off-balance-sheet credit exposures primarily consist of amounts available under outstanding lines of credit and letters of credit detailed in the table above. For the period of exposure, the estimate of expected credit losses considers both the likelihood that funding will occur and the amount expected to be funded over the estimated remaining life of the commitment or other off-balance-sheet exposure. The likelihood and expected amount of funding are based on historical utilization rates. The amount of the allowance represents management's best estimate of expected credit losses on commitments expected to be funded over the contractual life of the commitment. Estimating credit losses on amounts expected to be funded uses the same methodology as described for loans in Note 3 - Loans as if such commitments were funded. This methodology was also impacted by the model updates during 2024 and 2023, as described in Note 3 - Loans. For 2024, the overall approximate impact of the model updates was a $1.8 million increase in modeled expected credit losses for off-balance-sheet credit exposures ($1.6 million related to consumer and other loan commitments and $211 thousand related to non-owner-occupied commercial real estate loan commitments). For 2023, the overall approximate impact of the model updates was a $19.0 million decrease in modeled expected credit losses for off-balance-sheet credit exposures, though the impact of this decrease was largely offset with discretionary qualitative adjustments. The following table details activity in the allowance for credit losses on off-balance-sheet credit exposures. 2024 2023 2022 Beginning balance $ 51,751 $ 58,593 $ 50,314 Credit loss expense (benefit) 153 (6,842) 8,279 Ending balance $ 51,904 $ 51,751 $ 58,593 Credit Card Guarantees . We guarantee the credit card debt of certain customers to the merchant bank that issues the cards. At December 31, 2024 and 2023, the guarantees totaled approximately $4.9 million and $5.5 million, of which amounts, $673 thousand and $762 thousand were fully collateralized. Trust Accounts . We hold certain assets which are not included in our consolidated balance sheets including assets held in fiduciary or custodial capacity on behalf of our trust customers. The estimated fair value of trust assets was approximately $51.4 billion and $47.2 billion at December 31, 2024 and 2023, respectively. These assets are primarily composed of equity securities, fixed income securities, alternative investments and cash equivalents, among other things. Executive Change-In-Control Severance Plan . We maintain a change-in-control severance plan for the benefit of certain executive officers. Under this plan, each covered person could receive, upon the effectiveness of a change-in-control, two to three times (depending on the person) their base compensation plus the target bonus established for the year, and any unpaid base salary and pro rata target bonus for the year in which the termination occurs, including vacation pay. Additionally, the executive’s insurance benefits will continue for two to three full years after the termination and all long-term incentive awards will immediately vest. Litigation . We are subject to various claims and legal actions that have arisen in the course of conducting business. Management does not expect the ultimate disposition of these matters to have a material adverse impact on our financial statements.

Capital and Regulatory Matters

Capital and Regulatory Matters	12 Months Ended
	Dec. 31, 2024
Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract]
Capital and Regulatory Matters	Capital and Regulatory Matters 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 amounts and classifications are also subject to qualitative judgments by regulators about components, risk weighting and other factors. Cullen/Frost and Frost Bank are each required to comply with applicable capital adequacy standards established by the Federal Reserve Board (the “Basel III Capital Rules”). Quantitative measures established by the Basel III Capital Rules designed to ensure capital adequacy require the maintenance of minimum amounts and ratios (set forth below) of Common Equity Tier 1 capital, Tier 1 capital and Total capital (as defined in the regulations) to risk-weighted assets (as defined), and of Tier 1 capital to adjusted quarterly average assets (as defined). Cullen/Frost’s and Frost Bank’s Common Equity Tier 1 capital includes common stock and related paid-in capital, net of treasury stock, and retained earnings. In connection with the adoption of the Basel III Capital Rules, we elected to opt-out of the requirement to include most components of accumulated other comprehensive income in Common Equity Tier 1. We also elected to exclude the effects of credit loss accounting under CECL from Common Equity Tier 1 capital for a five Frost Bank's Common Equity Tier 1 is also reduced by its equity investment in its financial subsidiary, Frost Insurance Agency (“FIA”). Tier 1 capital includes Common Equity Tier 1 capital and additional Tier 1 capital. For Cullen/Frost, additional Tier 1 capital at December 31, 2024 and 2023 included $145.5 million of 4.450% non-cumulative perpetual preferred stock, the details of which is are further discussed below. Frost Bank did not have any additional Tier 1 capital beyond Common Equity Tier 1 at December 31, 2024 or 2023. Total capital includes Tier 1 capital and Tier 2 capital. Tier 2 capital for both Cullen/Frost and Frost Bank includes a permissible portion of the allowance for credit losses on securities, loans and off-balance sheet exposures. Tier 2 capital for Cullen/Frost also includes trust preferred securities that were excluded from Tier 1 capital and qualified subordinated debt. Cullen/Frost's Tier 2 capital included $120.0 million of trust preferred securities at both December 31, 2024 and 2023. Cullen/Frost's Tier 2 Capital also included $40.0 million at December 31, 2024 and $60.0 million at December 31, 2023 related to the permissible portion of our aggregate $100 million of 4.50% subordinated notes. The permissible portion of qualified subordinated notes decreases 20% per year during the final five The Common Equity Tier 1, 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, with certain exclusions, 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. The Basel III Capital Rules require Cullen/Frost and Frost Bank to maintain (i) a minimum ratio of Common Equity Tier 1 capital to risk-weighted assets of at least 4.5%, plus a 2.5% “capital conservation buffer” (which is added to the 4.5% Common Equity Tier 1 capital ratio, effectively resulting in a minimum ratio of Common Equity Tier 1 capital to risk-weighted assets of at least 7.0%), (ii) a minimum ratio of Tier 1 capital to risk-weighted assets of at least 6.0%, plus the capital conservation buffer (which is added to the 6.0% Tier 1 capital ratio, effectively resulting in a minimum Tier 1 capital ratio of 8.5%), (iii) a minimum ratio of Total capital (that is, Tier 1 plus Tier 2) to risk-weighted assets of at least 8.0%, plus the capital conservation buffer (which is added to the 8.0% total capital ratio, effectively resulting in a minimum total capital ratio of 10.5%) and (iv) a minimum leverage ratio of 4.0%, calculated as the ratio of Tier 1 capital to average quarterly assets. The capital conservation buffer is designed to absorb losses during periods of economic stress and, as detailed above, effectively increases the minimum required risk-weighted capital ratios. Banking institutions with a ratio of Common Equity Tier 1 capital to risk-weighted assets below the effective minimum (4.5% plus the capital conservation buffer and, if applicable, the “countercyclical capital buffer,” which is discussed below) will face constraints on dividends, equity repurchases and compensation based on the amount of the shortfall and the institution's “eligible retained income” (that is, four quarter trailing net income, net of distributions and tax effects not reflected in net income). The countercyclical capital buffer is applicable to only certain covered institutions and does not have any current applicability to Cullen/Frost or Frost Bank. The following table presents actual and required capital ratios as of December 31, 2024 and December 31, 2023 for Cullen/Frost and Frost Bank under the Basel III Capital Rules. Capital levels required to be considered well capitalized are based upon prompt corrective action regulations, as amended to reflect the changes under the Basel III Capital Rules. Actual Minimum Capital Required to be Considered Well Capitalized (1) Capital Ratio Capital Ratio Capital Ratio 2024 Common Equity Tier 1 to Risk-Weighted Assets Cullen/Frost $ 4,343,666 13.62 % $ 2,232,822 7.00 % N/A N/A Frost Bank 4,387,862 13.76 2,231,710 7.00 $ 2,072,302 6.50 % Tier 1 Capital to Risk-Weighted Assets Cullen/Frost 4,489,118 14.07 2,711,283 8.50 1,913,847 6.00 Frost Bank 4,387,862 13.76 2,709,934 8.50 2,550,526 8.00 Total Capital to Risk-Weighted Assets Cullen/Frost 4,954,136 15.53 3,349,232 10.50 3,189,745 10.00 Frost Bank 4,692,880 14.72 3,347,565 10.50 3,188,157 10.00 Leverage Ratio Cullen/Frost 4,489,118 8.63 2,079,715 4.00 N/A N/A Frost Bank 4,387,862 8.44 2,079,965 4.00 2,599,956 5.00 2023 Common Equity Tier 1 to Risk-Weighted Assets Cullen/Frost $ 4,036,945 13.25 % $ 2,132,516 7.00 % N/A N/A Frost Bank 4,057,111 13.33 2,129,784 7.00 $ 1,977,656 6.50 % Tier 1 Capital to Risk-Weighted Assets Cullen/Frost 4,182,397 13.73 2,589,484 8.50 1,827,871 6.00 Frost Bank 4,057,111 13.33 2,586,166 8.50 2,434,038 8.00 Total Capital to Risk-Weighted Assets Cullen/Frost 4,625,760 15.18 3,198,774 10.50 3,046,452 10.00 Frost Bank 4,320,474 14.20 3,194,676 10.50 3,042,548 10.00 Leverage Ratio Cullen/Frost 4,182,397 8.35 2,003,020 4.00 N/A N/A Frost Bank 4,057,111 8.10 2,003,152 4.00 2,503,940 5.00 ____________________ (1) “Well-capitalized” minimum Common Equity Tier 1 to Risk-Weighted Assets and Leverage Ratio are not formally defined under applicable banking regulations for bank holding companies. As of December 31, 2024, capital levels for Cullen/Frost and Frost Bank exceed all capital adequacy requirements under the Basel III Capital Rules. Based on the ratios presented above, capital levels as of December 31, 2024 for Cullen/Frost and Frost Bank exceed the minimum levels necessary to be considered “well capitalized.” Cullen/Frost and Frost Bank are subject to the regulatory capital requirements administered by the Federal Reserve Board and, for Frost Bank, the Federal Deposit Insurance Corporation (“FDIC”). Regulatory authorities can initiate certain mandatory actions if Cullen/Frost or Frost Bank fail to meet the minimum capital requirements, which could have a direct material effect on our financial statements. Management believes, as of December 31, 2024, that Cullen/Frost and Frost Bank meet all capital adequacy requirements to which they are subject. Series B Preferred Stock. We have issued 150,000 shares, or $150.0 million in aggregate liquidation preference, of our 4.450% Non-Cumulative Perpetual Preferred Stock, Series B, par value $0.01 and liquidation preference $1,000 per share (“Series B Preferred Stock”). Each share of Series B Preferred Stock issued and outstanding is represented by 40 depositary shares, each representing a 1/40th ownership interest in a share of the Series B Preferred Stock (equivalent to a liquidation preference of $25 per share). Each holder of depositary shares is entitled, in proportion to the applicable fraction of a share of Series B Preferred Stock represented by such depositary shares, to all rights and preferences of the Series B Preferred Stock represented thereby (including dividend, voting, redemption, and liquidation rights). Such rights must be exercised through the depositary. Dividends on the Series B Preferred Stock are non-cumulative and, if declared, accrue and are payable quarterly, in arrears, at a rate of 4.450% per annum. The Series B Preferred Stock qualifies as Tier 1 capital for the purposes of the regulatory capital calculations. The net proceeds from the issuance and sale of the Series B Preferred Stock, after deducting $4.5 million of issuance costs including the underwriting discount and professional service fees, among other things, were approximately $145.5 million. The Series B Preferred Stock is perpetual and has no maturity date. We may redeem the Series B Preferred Stock at our option (i) in whole or in part, from time to time, on any dividend payment date on or after December 15, 2025 or (ii) in whole but not in part, within 90 days following certain changes in laws or regulations impacting the regulatory capital treatment of the Series B Preferred Stock, in either case, at a redemption price equal to $1,000 per share of Series B Preferred Stock (equivalent to $25 per depositary share), plus any declared and unpaid dividends for prior dividend periods and accrued but unpaid dividends (whether or not declared) for the then-current dividend period prior to but excluding the redemption date. If we redeem the Series B Preferred Stock, the depositary is expected redeem a proportionate number of depositary shares. Neither the holders of Series B Preferred Stock nor holders of depositary shares will have the right to require the redemption or repurchase of the Series B Preferred Stock or the depositary shares. Purchases of Equity Securities. From time to time, our board of directors has authorized stock repurchase plans. On January 24, 2024, our board of directors authorized a $150.0 million stock repurchase plan (the “2024 Repurchase Plan”), allowing us to repurchase shares of our common stock over a one Under a prior publicly announced stock repurchase plan, we repurchased 400,868 shares at a total cost of $39.0 million during 2023. No shares were repurchased under a publicly announced stock repurchase plan during 2022. Shares repurchased in connection with the vesting of certain share awards totaled 35,897 at a total cost of $3.5 million in 2023 and 31,351 at a total cost of $4.4 million in 2022. On January 29, 2025, our board of directors authorized a $150.0 million stock repurchase plan (the “2025 Repurchase Plan”), allowing us to repurchase shares of our common stock over a one Capital simplification rules adopted by federal bank regulators in 2019 eliminated the standalone prior approval requirement in the Basel III Capital Rules for any repurchase of common stock. In certain circumstances, Cullen/Frost’s repurchases of its common stock may be subject to a prior approval or notice requirement under other regulations, policies or supervisory expectations of the Federal Reserve Board. Any redemption or repurchase of preferred stock or subordinated debt remains subject to the prior approval of the Federal Reserve Board. The Inflation Reduction Act of 2022 (the “IRA”) imposes a 1% excise tax on the fair market value of stock repurchased after December 31, 2022 by publicly traded U.S. corporations. With certain exceptions, the value of stock repurchased is determined net of stock issued in the year, including shares issued pursuant to compensatory arrangements. Dividend Restrictions . In the ordinary course of business, Cullen/Frost is dependent upon dividends from Frost Bank to provide funds for the payment of dividends to shareholders and to provide for other cash requirements, including to repurchase its common stock. Banking regulations may limit the amount of dividends that may be paid. Approval by regulatory authorities is required if the effect of dividends declared would cause the regulatory capital of Frost Bank to fall below specified minimum levels. Approval is also required if dividends declared exceed the net profits for that year combined with the retained net profits for the preceding two years. Under the foregoing dividend restrictions and while maintaining its “well capitalized” status, at December 31, 2024, Frost Bank could pay aggregate dividends of up to $1.2 billion to Cullen/Frost without prior regulatory approval. Under the terms of the junior subordinated deferrable interest debentures that Cullen/Frost has issued to Cullen/Frost Capital Trust II, Cullen/Frost has the right at any time during the term of the debentures to defer the payment of interest at any time or from time to time for an extension period not exceeding 20 consecutive quarterly periods with respect to each extension period. In the event that we have elected to defer interest on the debentures, we may not, with certain exceptions, declare or pay any dividends or distributions on our capital stock or purchase or acquire any of our capital stock. Under the terms of the Series B Preferred Stock, in the event that we do not declare and pay dividends on the Series B Preferred Stock for the most recent dividend period, we may not, with certain exceptions, declare or pay dividends on, or purchase, redeem or otherwise acquire, shares of our common stock or any of our securities that rank junior to the Series B Preferred Stock. Insider Trading Policies and Procedures. Our board of directors has adopted insider trading policies and procedures governing the purchase, sale, and/or other dispositions of our securities by directors, officers and employees, or by Cullen/Frost itself. These policies have been reasonably designed to promote compliance with insider trading laws, rules and regulations, and applicable New York Stock Exchange listing standards.

Earnings Per Common Share

Earnings Per Common Share	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Earnings Per Common Share	Earnings Per Common Share Earnings Per Common Share . Earnings per common share is computed using the two-class method. Basic earnings per common share is computed by dividing net earnings allocated to common stock by the weighted-average number of common shares outstanding during the applicable period, excluding outstanding participating securities. Participating securities include non-vested restricted stock units, deferred stock units and performance stock units (during the performance period), though no actual shares of common stock related to any type of stock unit have been issued. Non-vested restricted stock units and deferred stock units are considered participating securities because holders of these securities receive non-forfeitable dividends at the same rate as holders of our common stock. Holders of performance stock units receive dividend equivalent payments for dividends paid during the performance period at the vesting date of the award based upon the number of units that ultimately vest. Diluted earnings per common share is computed using the weighted-average number of shares determined for the basic earnings per common share computation plus the dilutive effect of stock compensation using the treasury stock method. The following table presents a reconciliation of net income available to common shareholders, net earnings allocated to common stock and the number of shares used in the calculation of basic and diluted earnings per common share. 2024 2023 2022 Net Income $ 582,542 $ 597,973 $ 579,150 Less: Preferred stock dividends 6,675 6,675 6,675 Net income available to common shareholders 575,867 591,298 572,475 Less: Earnings allocated to participating securities 6,236 6,283 5,210 Net earnings allocated to common stock $ 569,631 $ 585,015 $ 567,265 Distributed earnings allocated to common stock $ 239,879 $ 229,749 $ 207,924 Undistributed earnings allocated to common stock 329,752 355,266 359,341 Net earnings allocated to common stock $ 569,631 $ 585,015 $ 567,265 Weighted-average shares outstanding for basic earnings per common share 64,120,455 64,204,239 64,156,870 Dilutive effect of stock compensation 142,191 200,594 363,648 Weighted-average shares outstanding for diluted earnings per common share 64,262,646 64,404,833 64,520,518

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2024
Retirement Benefits [Abstract]
Employee Benefit Plans	Employee Benefit Plans Retirement Plans Retirement Plan and Restoration Plan. We maintain a non-contributory defined benefit plan (the “Retirement Plan”) that was frozen as of December 31, 2001. The plan provides pension and death benefits to substantially all employees who were at least 21 years of age and had completed at least one year of service prior to December 31, 2001. Defined benefits are provided based on an employee’s final average compensation and years of service at the time the plan was frozen and age at retirement. The freezing of the plan provides that future salary increases will not be considered. Our funding policy is to contribute yearly, at least the amount necessary to satisfy the funding standards of the Employee Retirement Income Security Act (“ERISA”). Our Restoration of Retirement Income Plan (the “Restoration Plan”) provides benefits for eligible employees that are in excess of the limits under Section 415 of the Internal Revenue Code of 1986, as amended, that apply to the Retirement Plan. The Restoration Plan is designed to comply with the requirements of ERISA. The entire cost of the plan, which was also frozen as of December 31, 2001, is supported by our contributions. We use a December 31 measurement date for our defined benefit plans. Combined activity in our defined benefit pension plans was as follows: 2024 2023 2022 Change in plan assets: Fair value of plan assets at beginning of year $ 174,611 $ 161,823 $ 197,747 Actual return on plan assets 5,306 22,477 (26,108) Employer contributions 1,150 1,105 1,114 Benefits paid (11,340) (10,794) (10,930) Fair value of plan assets at end of year 169,727 174,611 161,823 Change in benefit obligation: Benefit obligation at beginning of year 142,372 143,944 185,925 Interest cost 6,647 6,983 4,017 Actuarial (gain) loss (6,779) 2,239 (35,068) Benefits paid (11,340) (10,794) (10,930) Benefit obligation at end of year 130,900 142,372 143,944 Funded status of the plan at end of year and accrued benefit (liability) recognized $ 38,827 $ 32,239 $ 17,879 Accumulated benefit obligation at end of year $ 130,900 $ 142,372 $ 143,944 Certain disaggregated information related to our defined benefit pension plans as of year-end was as follows: Retirement Plan Restoration Plan 2024 2023 2024 2023 Projected benefit obligation $ 120,179 $ 130,750 $ 10,721 $ 11,622 Accumulated benefit obligation 120,179 130,750 10,721 11,622 Fair value of plan assets 169,727 174,611 — — Funded status of the plan at end of year and accrued benefit (liability) recognized 49,548 43,861 (10,721) (11,622) The components of the combined net periodic cost (benefit) for our defined benefit pension plans are presented in the table below. 2024 2023 2022 Expected return on plan assets, net of expenses $ (9,645) $ (10,959) $ (13,966) Interest cost on projected benefit obligation 6,647 6,983 4,017 Net amortization and deferral 1,673 3,479 2,964 Net periodic expense (benefit) $ (1,325) $ (497) $ (6,985) Amounts related to our defined benefit pension plans recognized as a component of other comprehensive income were as follows: 2024 2023 2022 Net actuarial gain (loss) $ 4,112 $ 12,757 $ (2,041) Deferred tax (expense) benefit (863) (2,679) 429 Other comprehensive income (loss), net of tax $ 3,249 $ 10,078 $ (1,612) Amounts recognized as a component of accumulated other comprehensive loss as of year-end that have not been recognized as a component of the combined net periodic benefit cost of our defined benefit pension plans are presented in the following table. 2024 2023 Net actuarial loss $ (26,806) $ (30,918) Deferred tax benefit 5,630 6,493 Amounts included in accumulated other comprehensive income/loss, net of tax (21,176) (24,425) The weighted-average assumptions used to determine the benefit obligations as of the end of the years indicated and the net periodic benefit cost for the years indicated are presented in the table below. Because the plans were frozen, increases in compensation are not considered after 2001. 2024 2023 2022 Benefit obligations: Discount rate 5.58 % 4.95 % 5.14 % Net periodic benefit cost: Discount rate 4.95 % 5.14 % 2.79 % Expected return on plan assets 5.70 7.00 7.25 Management uses an asset allocation optimization model to analyze the potential risks and rewards associated with various asset allocation strategies on a quarterly basis. As of December 31, 2024, management’s investment objective for our defined benefit plans is to achieve current income with growth through price appreciation. This strategy provides for a target asset allocation of approximately 64% invested in fixed income debt securities and approximately 31% invested in equity securities with any remainder invested in cash or short-term cash equivalents. The asset allocation optimization process provides portfolio allocations which best represent the potential risk associated with a given asset allocation over a full market cycle. This is used to help management determine an appropriate mix of assets in order to achieve the plan's long term investment goals. The plan assets are reviewed annually to determine if the obligations can be met with the current investment mix and funding strategy. The major categories of assets in our Retirement Plan as of year-end are presented in the following table. Assets are segregated by the level of the valuation inputs within the fair value hierarchy established by ASC Topic 820 “Fair Value Measurements and Disclosures,” utilized to measure fair value (see Note 16 - Fair Value Measurements). Our Restoration Plan is unfunded. 2024 2023 Level 1: Mutual funds and ETFs $ 34,564 $ 38,793 U.S. Treasury 24,341 26,633 Common stock 14,921 13,001 Cash and cash equivalents 431 1,241 Level 2: Corporate bonds and notes 62,405 58,669 U.S. government agency securities 7,232 7,041 States and political subdivisions 25,833 29,233 Total fair value of plan assets $ 169,727 $ 174,611 Mutual funds and exchange traded funds (“ETFs”) include various equity, fixed-income and blended funds with varying investment strategies. Approximately 74% of mutual fund investments consist of equity investments as of December 31, 2024. The investment objective of equity funds and other equity investments is long-term capital appreciation with current income. The remaining mutual fund investments consist of diversified corporate bonds and notes; U.S. and international government securities; mortgage-related and other asset-backed securities and loan participations. The investment objective of fixed-income funds and other fixed-income investments is to maximize investment return while preserving investment principal. Our investment strategies prohibit selling assets short and the use of derivatives. Additionally, our defined benefit plans do not directly invest in real estate, commodities, or private investments. The asset allocation optimization model is used to estimate the expected long-term rate of return for a given asset allocation strategy. Expectations of returns for each asset class are based on comprehensive reviews of historical data and economic/financial market theory. During periods with volatile interest rates and equity security prices, the model may call for changes in the allocation of plan investments to achieve desired returns. Management assumed a long-term rate of return of 5.70% in the determination of the net periodic benefit cost for 2024. The expected long-term rate of return on assets was selected from within the reasonable range of rates determined by historical real returns, net of inflation, for the asset classes covered by the plan’s investment policy and projections of inflation over the long-term period during which benefits are payable to plan participants. As of December 31, 2024, expected future benefit payments related to our defined benefit plans were as follows: 2025 $ 12,080 2026 12,025 2027 11,905 2028 11,596 2029 11,488 2030 through 2034 49,199 $ 108,293 We expect to contribute $1.1 million to the defined benefit plans during 2025. Savings Plans 401(k) Stock Purchase Plan and Other Plans. We maintain a 401(k) stock purchase plan that permits each participant to make before-tax contributions in an amount not less than 2% and not exceeding 50% of eligible compensation and subject to dollar limits from Internal Revenue Service regulations. We match 100% of the employee’s contributions to the plan based on the amount of each participant’s contributions up to a maximum of 6% of eligible compensation. Eligible employees must complete 30 days of service in order to enroll and vest in our matching contributions immediately. Our matching contribution is initially invested in the common stock of Cullen/Frost. Employees may immediately reallocate our matching portion, as well as invest their individual contribution, to any of a variety of investment alternatives offered under the 401(k) Plan. We may also make discretionary profit sharing contributions to eligible participants. Expense related to the plan, including both 401(k) and profit sharing contributions, totaled $30.4 million in 2024, $32.3 million in 2023 and $28.0 million in 2022. We maintain a thrift incentive stock purchase plan and a separate non-qualified profit sharing plan to offer certain employees, whose participation in the 401(k) plan is limited, an alternative means of receiving comparable benefits. Expense related to these plans was not significant during 2024, 2023 and 2022. Stock Compensation Plans We have three active stock compensation plans (the 2007 Outside Directors Incentive Plan, the 2015 Omnibus Incentive Plan, and the 2024 Equity Incentive Plan). All of the plans have been approved by our shareholders. The 2024 Equity Incentive Plan (the “2024 Plan”) was approved by our shareholders on April 24, 2024 to replace the 2015 Omnibus Incentive Plan (the “2015 Plan”). Under the 2024 Plan, shareholders approved the issuance, pursuant to the plan, of 2,576,038 shares of our common stock. This amount included 2,350,000 newly authorized shares and the 226,038 shares remaining available for issuance under the superseded 2015 Plan. The 2015 Plan had previously superseded the 2007 Outside Directors Incentive Plan (the “2007 Directors Plan”) and the 2005 Omnibus Incentive Plan, which is no longer active. Our stock compensation plans were established to (i) motivate superior performance by means of performance-related incentives, (ii) encourage and provide for the acquisition of an ownership interest in our company by employees and non-employee directors and (iii) enable us to attract and retain qualified and competent persons as employees and to serve as members of our board of directors. Under the 2024 Plan, we may grant, among other things, nonqualified stock options, incentive stock options, stock awards, stock appreciation rights, restricted stock units, performance share units or any combination thereof to certain employees and non-employee directors. Any of the authorized shares may be used for any type of award allowable under the Plan. The Compensation and Benefits Committee (“Committee”) of our Board of Directors has sole authority to (i) establish the awards to be issued, (ii) select the employees and non-employee directors to receive awards, and (iii) approve the terms and conditions of each award contract. Each award under the stock plans is evidenced by an award agreement that specifies the award price, the duration of the award, the number of shares to which the award pertains, and such other provisions as the Committee determines. For stock options, the option price for each grant is at least equal to the fair market value of a share of Cullen/Frost’s common stock on the date of grant. Options granted expire at such time as the Committee determines at the date of grant and in no event does the exercise period exceed a maximum of ten years. As defined in the plans, outstanding unvested awards may immediately vest upon a change-in-control of Cullen/Frost and subsequent termination resulting from the change in control. A combined summary of activity in our active stock plans is presented in the table. Performance stock units outstanding are presented assuming attainment of the maximum payout rate as set forth by the performance criteria. The target award level for performance stock units granted in 2024, 2023 and 2022 was 21,554, 66,471 and 35,015, respectively. As of December 31, 2024, there were 2,361,570 shares remaining available for grant for future awards. Director Deferred Non-Vested Performance Stock Units Outstanding Stock Options Number of Units Weighted- Number Weighted- Number of Units Weighted- Number Weighted- January 1, 2021 56,301 $ 79.21 449,337 $ 93.05 202,460 $ 84.71 877,681 $ 69.02 Granted 5,382 133.67 119,176 142.56 52,527 133.40 — — Exercised/vested (16,022) 74.89 (97,154) 94.81 (25,180) 87.18 (261,454) 63.72 Forfeited/expired — — (6,040) 93.28 (16,058) 87.18 — — December 31, 2022 45,661 87.15 465,319 105.36 213,749 96.20 616,227 71.27 Granted 8,503 103.47 217,561 85.39 99,710 74.71 — — Exercised/vested — — (108,920) 94.00 (28,151) 85.74 (130,286) 71.37 Forfeited/expired — — (7,154) 114.53 (18,254) 85.74 — — December 31, 2023 54,164 89.71 566,806 99.77 267,054 89.99 485,941 71.25 Granted 7,997 116.84 176,892 129.44 32,334 119.17 — — Exercised/vested (9,382) 80.99 (232,617) 91.78 (45,818) 57.89 (301,965) 74.98 Forfeited/expired — — (3,219) 106.74 (22,913) 57.89 — — December 31, 2024 52,779 95.37 507,862 113.72 230,657 103.65 183,976 65.11 Director deferred stock units granted to non-employee directors generally have immediate vesting. Upon retirement from our board of directors, non-employee directors will receive one share of our common stock for each director deferred stock unit held. Non-vested restricted stock units granted to employees generally have a three four Performance stock units represent shares potentially issuable in the future. For performance stock units granted in 2024, and years prior to 2021, issuance is based upon the measure of our achievement of relative return on assets over a three-year performance period compared to an identified peer group's achievement of relative return on assets over the same three-year performance period. For performance stock units granted in 2023, 2022, and 2021, issuance is based upon the measure of our achievement of growth in adjusted net revenue, averaged over the three-year performance period, compared to the 2023, 2022, and 2021 base-year amounts, respectively. Performance stock units are eligible to receive equivalent dividend payments based on declared dividends on our common stock during the performance period. Equivalent dividend payments are based upon the ultimate number of shares issued under each performance award and are deferred until such time that the units vest and shares are issued. Options granted to employees generally have a ten four Shares issued in connection with stock compensation awards are issued from available treasury shares. If no treasury shares are available, new shares are issued from available authorized shares. Shares issued in connection with stock compensation awards along with other related information were as follows: 2024 2023 2022 New shares issued from available authorized shares — 49,887 118,389 Shares issued from available treasury stock 589,782 217,470 281,421 Total 589,782 267,357 399,810 Proceeds from stock option exercises $ 22,643 $ 9,299 $ 16,659 Intrinsic value of stock options exercised 13,454 3,614 19,616 Fair value of restricted/director deferred stock units vested 35,922 13,445 19,308 Stock-based Compensation Expense. Stock-based compensation expense is recognized ratably over the requisite service period for all awards. For most stock option awards, the service period generally matches the vesting period. For stock options granted to certain executive officers and for non-vested restricted stock units granted to all participants, the service period does not extend past the date the participant reaches 65 years of age. Director deferred stock units granted to non-employee directors generally have immediate vesting and the related expense is fully recognized on the date of grant. For performance stock units, the service period generally matches the three-year performance period specified by the award, however, the service period does not extend past the date the participant reaches 65 years of age. Expense recognized each period is dependent upon our estimate of the number of shares that will ultimately be issued. Stock-based compensation expense and the related income tax benefit is presented in the following table. The service period for performance stock units granted each year begins on January 1 of the following year. 2024 2023 2022 Non-vested restricted stock units $ 19,457 $ 16,734 $ 13,162 Director deferred stock units 934 880 720 Performance stock units (628) 6,976 4,440 Total $ 19,763 $ 24,590 $ 18,322 Income tax benefit $ 4,776 $ 4,120 $ 2,969 Unrecognized stock-based compensation expense and the weighted-average period over which the expense is expected to be recognized at December 31, 2024 is presented in the table below. Unrecognized stock-based compensation expense related to performance stock units is presented assuming attainment of the maximum payout rate as set forth by the performance criteria. Unrecognized Expense Weighted-Average Number of Years for Expense Recognition Non-vested restricted stock units $ 25,827 2.20 Performance stock units 12,912 2.02 Total $ 38,739 Valuation of Stock-Based Compensation . For the purposes of recognizing stock-based compensation expense, the fair value of non-vested restricted stock units and director deferred stock units is generally the market price of the stock on the measurement date, which, for us, is the date of the award. The fair value of performance stock units is determined in a similar manner except that the market price of the stock on the measurement date is discounted by the present value of the dividends expected to be paid on our common stock during the service period of the award because dividend equivalent payments on performance stock units are deferred until such time that the units vest and shares are issued. In applying this discount to the market price of our stock on the measurement date, we assumed we would pay a flat quarterly dividend during the service period equal to our most recent dividend payment, which was $0.95, $0.92 and $0.87 in 2024, 2023 and 2022, respectively, discounted at a weighted-average risk-free rate of 4.09%, 5.01% and 4.45% in 2024, 2023 and 2022, respectively.

Other Non-Interest Income and E

Other Non-Interest Income and Expense	12 Months Ended
	Dec. 31, 2024
Other Income and Expenses [Abstract]
Other Non-Interest Income and Expense	Other Non-Interest Income and Expense Other non-interest income and expense totals are presented in the following table. Components of these totals exceeding 1% of the aggregate of total net interest income and total non-interest income for any of the years presented are stated separately. 2024 2023 2022 Other non-interest income: Other $ 52,060 $ 54,941 $ 45,217 Total $ 52,060 $ 54,941 $ 45,217 Other non-interest expense: Professional services $ 56,385 $ 53,932 $ 40,908 Advertising, promotions and public relations 51,403 48,608 39,994 Other 136,623 126,827 113,799 Total $ 244,411 $ 229,367 $ 194,701 In the ordinary course of business, we transact with certain directors and/or their affiliates. Payments for services provided totaled $1.8 million in 2024, $1.3 million in 2023 and $545 thousand in 2022.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income tax expense was as follows: 2024 2023 2022 Current income tax expense $ 125,025 $ 129,229 $ 94,595 Deferred income tax expense (benefit) (11,600) (14,829) (4,918) Income tax expense, as reported $ 113,425 $ 114,400 $ 89,677 Effective tax rate 16.3 % 16.1 % 13.4 % A reconciliation between reported income tax expense and the amounts computed by applying the U.S. federal statutory income tax rate of 21% to income before income taxes is presented in the following table. 2024 2023 2022 Income tax expense computed at the statutory rate $ 146,153 $ 149,598 $ 140,454 Effect of tax-exempt interest (38,498) (43,114) (50,602) Net tax benefit from stock-based compensation (3,795) (894) (4,602) Tax benefit on dividends paid in our 401k plan (2,281) (2,135) (1,854) Non-deductible FDIC premiums 5,943 5,263 3,277 Non-deductible meals and entertainment 1,861 1,692 683 Non-deductible compensation 1,629 2,591 2,250 Other 2,413 1,399 71 Income tax expense, as reported $ 113,425 $ 114,400 $ 89,677 There were no unrecognized tax benefits during any of the reported periods. Interest and/or penalties related to income taxes are reported as a component of income tax expense. Such amounts were not significant during the reported periods. Year-end deferred taxes are presented in the table below. Deferred taxes are based on the U.S. statutory federal income tax rate of 21%. 2024 2023 Deferred tax assets: Net unrealized loss on securities available for sale and transferred securities $ 327,184 $ 291,023 Allowance for credit losses 67,697 62,592 Lease liabilities under operating leases 64,691 66,442 Bonus accrual 13,753 9,680 FDIC deposit insurance special assessment 8,647 9,468 Stock-based compensation 6,321 7,712 Net actuarial loss on defined benefit post-retirement benefit plans 5,630 6,493 Deferred loan and lease origination fees 3,990 4,129 Other 6,496 5,892 Total gross deferred tax assets 504,409 463,431 Deferred tax liabilities: Right-of-use assets under operating leases (56,759) (58,905) Premises and equipment (38,352) (42,640) Intangible assets (18,048) (18,106) Defined benefit post-retirement benefit plans (13,591) (13,073) Other (2,422) (2,368) Total gross deferred tax liabilities (129,172) (135,092) Net deferred tax asset (liability) $ 375,237 $ 328,339 No valuation allowance for deferred tax assets was recorded at December 31, 2024 and 2023 as management believes it is more likely than not that all of the deferred tax assets will be realized against deferred tax liabilities and projected future taxable income. There were no unrecognized tax benefits during any of the reported periods. We file income tax returns in the U.S. federal jurisdiction. We are no longer subject to U.S. federal income tax examinations by tax authorities for years before 2021.

Other Comprehensive Income (Los

Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Other Comprehensive Income (Loss)	Other Comprehensive Income (Loss) The tax effects allocated to each component of other comprehensive income (loss) were as follows: Before Tax Tax Expense, Net of Tax 2024 Securities available for sale and transferred securities: Change in net unrealized gain/loss during the period $ (171,662) $ (36,049) $ (135,613) Change in net unrealized gain on securities transferred to held to maturity (629) (132) (497) Reclassification adjustment for net (gains) losses included in net income 96 20 76 Total securities available for sale and transferred securities (172,195) (36,161) (136,034) Defined-benefit post-retirement benefit plans: Change in the net actuarial gain/loss 2,439 512 1,927 Reclassification adjustment for net amortization of actuarial gain/loss included in net income as a component of net periodic cost (benefit) 1,673 351 1,322 Total defined-benefit post-retirement benefit plans 4,112 863 3,249 Total other comprehensive income (loss) $ (168,083) $ (35,298) $ (132,785) Before Tax Tax Expense, Net of Tax 2023 Securities available for sale and transferred securities: Change in net unrealized gain/loss during the period $ 277,926 $ 58,364 $ 219,562 Change in net unrealized gain on securities transferred to held to maturity (649) (136) (513) Reclassification adjustment for net (gains) losses included in net income (66) (14) (52) Total securities available for sale and transferred securities 277,211 58,214 218,997 Defined-benefit post-retirement benefit plans: Change in the net actuarial gain/loss 9,278 1,948 7,330 Reclassification adjustment for net amortization of actuarial gain/loss included in net income as a component of net periodic cost (benefit) 3,479 731 2,748 Total defined-benefit post-retirement benefit plans 12,757 2,679 10,078 Total other comprehensive income (loss) $ 289,968 $ 60,893 $ 229,075 2022 Securities available for sale and transferred securities: Change in net unrealized gain/loss during the period $ (2,143,567) $ (450,149) $ (1,693,418) Change in net unrealized gain on securities transferred to held to maturity (737) (155) (582) Total securities available for sale and transferred securities (2,144,304) (450,304) (1,694,000) Defined-benefit post-retirement benefit plans: Change in the net actuarial gain/loss (5,005) (1,051) (3,954) Reclassification adjustment for net amortization of actuarial gain/loss included in net income as a component of net periodic cost (benefit) 2,964 622 2,342 Total defined-benefit post-retirement benefit plans (2,041) (429) (1,612) Total other comprehensive income (loss) $ (2,146,345) $ (450,733) $ (1,695,612) Activity in accumulated other comprehensive income, net of tax, was as follows: Securities Defined Accumulated 2024 Beginning balance $ (1,094,794) $ (24,425) $ (1,119,219) Other comprehensive income (loss) before reclassification (136,110) 1,927 (134,183) Reclassification of amounts included in net income 76 1,322 1,398 Net other comprehensive income (loss) during period (136,034) 3,249 (132,785) Ending balance $ (1,230,828) $ (21,176) $ (1,252,004) 2023 Beginning balance $ (1,313,791) $ (34,503) $ (1,348,294) Other comprehensive income (loss) before reclassification 219,049 7,330 226,379 Reclassification of amounts included in net income (52) 2,748 2,696 Net other comprehensive income (loss) during period 218,997 10,078 229,075 Ending balance $ (1,094,794) $ (24,425) $ (1,119,219) 2022 Beginning balance $ 380,209 $ (32,891) $ 347,318 Other comprehensive income (loss) before reclassification (1,694,000) (3,954) (1,697,954) Reclassification of amounts included in net income — 2,342 2,342 Net other comprehensive income (loss) during period (1,694,000) (1,612) (1,695,612) Ending balance $ (1,313,791) $ (34,503) $ (1,348,294)

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments The fair value of derivative positions outstanding is included in accrued interest receivable and other assets and accrued interest payable and other liabilities in the accompanying consolidated balance sheets and in the net change in each of these financial statement line items in the accompanying consolidated statements of cash flows. Interest Rate Derivatives. We utilize interest rate swaps, caps and floors to mitigate exposure to interest rate risk and to facilitate the needs of our customers. Our objectives for utilizing these derivative instruments are described below: From time to time, we have entered into certain interest rate derivative contracts that are designated as hedging instruments to hedge the risk of changes in the fair value of certain commercial loans/leases due to changes in interest rates. We also enter into certain interest rate derivative contracts that are not designated as hedging instruments to accommodate the business needs of our customers. These derivative contracts relate to transactions in which we enter into an interest rate swap, cap and/or floor with a customer while at the same time entering into an offsetting interest rate swap, cap and/or floor with a third-party financial institution. In connection with each swap transaction, we agree to pay interest to the customer on a notional amount at a variable interest rate and receive interest from the customer on a similar notional amount at a fixed interest rate. At the same time, we agree to pay a third-party financial institution the same fixed interest rate on the same notional amount and receive the same variable interest rate on the same notional amount. The transaction allows our customer to effectively convert a variable rate loan to a fixed rate. Because we act as an intermediary for our customers, changes in the fair value of the underlying derivative contracts largely offset each other and do not significantly impact our results of operations. The notional amounts and estimated fair values of interest rate derivative contracts outstanding are presented in the following table. The fair values of these contracts are estimated utilizing internal valuation methods with observable market data inputs, or as determined by the Chicago Mercantile Exchange (“CME”) for centrally cleared derivative contracts. CME rules legally characterize variation margin payments for centrally cleared derivatives as settlements of the derivatives' exposure rather than collateral. As a result, the variation margin payment and the related derivative instruments are considered a single unit of account for accounting and financial reporting purposes. Variation margin, as determined by the CME, is settled daily. As a result, derivative contracts that clear through the CME have an estimated fair value of zero at both December 31, 2024 and 2023. December 31, 2024 December 31, 2023 Notional Estimated Notional Estimated Non-hedging interest rate derivatives: Financial institution counterparties: Loan/lease interest rate swaps - assets $ 1,213,519 $ 63,001 $ 1,040,659 $ 58,486 Loan/lease interest rate swaps - liabilities 663,078 (9,068) 617,266 (20,293) Loan/lease interest rate caps - assets 205,164 7,053 275,000 11,747 Customer counterparties: Loan/lease interest rate swaps - assets 663,078 9,068 617,266 20,482 Loan/lease interest rate swaps - liabilities 1,213,519 (63,000) 1,040,659 (58,485) Loan/lease interest rate caps - liabilities 205,164 (7,054) 275,000 (11,747) The weighted-average rates paid and received for interest rate swaps outstanding at December 31, 2024 were as follows: Weighted-Average Interest Interest Interest rate swaps: Non-hedging interest rate swaps - financial institution counterparties 5.08 % 6.26 % Non-hedging interest rate swaps - customer counterparties 6.26 5.08 The weighted-average strike rate for outstanding interest rate caps was 3.66% at December 31, 2024. Commodity Derivatives. We enter into certain commodity derivative contracts that are not designated as hedging instruments to accommodate the business needs of our customers. Upon the origination of a commodity derivative contract with a customer, we simultaneously enter into an offsetting contract with a third-party financial institution to mitigate our exposure to fluctuations in commodity prices. Because we act as an intermediary for our customers, changes in the fair value of the underlying derivative contracts largely offset each other and do not significantly impact our results of operations. The notional amounts and estimated fair values of non-hedging commodity derivative contracts outstanding are presented in the following table. The fair values of these contracts are estimated utilizing internal valuation methods with observable market data inputs. December 31, 2024 December 31, 2023 Notional Notional Estimated Notional Estimated Financial institution counterparties: Oil - assets Barrels 7,097 $ 27,471 5,601 $ 37,667 Oil - liabilities Barrels 4,768 (12,897) 4,581 (18,500) Natural gas - assets MMBTUs 25,454 3,804 17,363 11,822 Natural gas - liabilities MMBTUs 26,082 (4,054) 6,462 (2,499) Customer counterparties: Oil - assets Barrels 4,872 $ 12,973 4,618 $ 18,722 Oil - liabilities Barrels 6,993 (26,753) 5,564 (36,877) Natural gas - assets MMBTUs 26,767 4,255 6,462 2,499 Natural gas - liabilities MMBTUs 24,769 (3,600) 17,363 (11,571) Foreign Currency Derivatives . We enter into foreign currency derivative contracts that are not designated as hedging instruments to accommodate the business needs of our customers and to mitigate our exposure to foreign currency. Upon the origination of a foreign currency derivative contract with a customer, we simultaneously enter into an offsetting contract with a third-party financial institution to mitigate our exposure to fluctuations in foreign currency exchange rates. Because we act as an intermediary for our customers, changes in the fair value of the underlying derivative contracts largely offset each other and do not significantly impact our results of operations. We also utilize foreign currency derivative contracts that are not designated as hedging instruments to mitigate the economic effect of fluctuations in foreign currency exchange rates on foreign currency holdings and certain short-term, non-U.S. dollar denominated loans. The notional amounts and fair values of non-hedging foreign currency derivative contracts are presented in the following table. The fair values of these contracts are estimated utilizing internal valuation methods with observable market data inputs. December 31, 2024 December 31, 2023 Notional Notional Estimated Notional Estimated Financial institution counterparties: Forward/option contracts - assets CAD — $ — 250 $ 1 Forward/option contracts - liabilities EUR — — 3,000 (14) Forward contracts - liabilities CAD — — 250 (5) Customer counterparties: Forward/option contracts - assets EUR — — 3,000 16 Forward/option contracts - assets CAD — — 250 5 Forward contracts - liabilities CAD — — 250 — Gains, Losses and Derivative Cash Flows . For fair value hedges, the changes in the fair value of both the derivative hedging instrument and the hedged item are included in other non-interest income or other non-interest expense. The extent that such changes in fair value do not offset represents hedge ineffectiveness. Net cash flows from interest rate swaps on commercial loans/leases designated as hedging instruments in effective hedges of fair value are included in interest income on loans. For non-hedging derivative instruments, gains and losses due to changes in fair value and all cash flows are included in other non-interest income and other non-interest expense. Amounts included in the consolidated statements of income related to interest rate derivatives designated as hedges of fair value were as follows: 2024 2023 2022 Commercial loan/lease interest rate swaps: Amount of gain (loss) included in interest income on loans $ — $ 16 $ (7) Amount of (gain) loss included in other non-interest expense — — 6 As stated above, we enter into non-hedge related derivative positions primarily to accommodate the business needs of our customers. Upon the origination of a derivative contract with a customer, we simultaneously enter into an offsetting derivative contract with a third-party financial institution. We recognize immediate income based upon the difference in the bid/ask spread of the underlying transactions with our customers and the third party. Because we act only as an intermediary for our customer, subsequent changes in the fair value of the underlying derivative contracts largely offset each other and do not significantly impact our results of operations. Amounts included in the consolidated statements of income related to non-hedging interest rate, commodity, foreign currency and other derivative instruments are presented in the table below. 2024 2023 2022 Non-hedging interest rate derivatives: Other non-interest income $ 4,304 $ 6,982 $ 1,742 Other non-interest expense 3 — — Non-hedging commodity derivatives: Other non-interest income 2,183 1,889 2,297 Non-hedging foreign currency derivatives: Other non-interest income 11 30 63 Counterparty Credit Risk. Derivative contracts involve the risk of dealing with both bank customers and financial institution counterparties and their ability to meet contractual terms. Financial institution counterparties must have an investment grade credit rating and be approved by our Asset/Liability Management Committee. Our credit exposure on derivative contracts is limited to the net favorable value of all contracts by each counterparty. Credit exposure may be reduced by the amount of collateral pledged by the counterparty. There are no credit-risk-related contingent features associated with any of our derivative contracts. Certain derivative contracts with financial institution counterparties may be terminated with respect to a party in the transaction, if such party does not have at least a minimum level rating assigned to either its senior unsecured long-term debt or its deposit obligations by certain third-party rating agencies.

Balance Sheet Offsetting

Balance Sheet Offsetting	12 Months Ended
	Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Balance Sheet Offsetting	Balance Sheet Offsetting and Repurchase Agreements Balance Sheet Offsetting. Certain financial instruments, including resell and repurchase agreements and derivatives, may be eligible for offset in the consolidated balance sheet and/or subject to master netting arrangements or similar agreements. Our derivative transactions with financial institution counterparties are generally executed under International Swaps and Derivative Association (“ISDA”) master agreements which include “right of set-off” provisions. In such cases there is generally a legally enforceable right to offset recognized amounts and there may be an intention to settle such amounts on a net basis. Nonetheless, we do not generally offset such financial instruments for financial reporting purposes. Information about financial instruments that are eligible for offset in the consolidated balance sheet as of December 31, 2024 is presented in the following tables. Gross Amount Gross Amount Net Amount December 31, 2024 Financial assets: Derivatives: Loan/lease interest rate swaps and caps $ 70,054 $ — $ 70,054 Commodity swaps and options 31,275 — 31,275 Total derivatives 101,329 — 101,329 Resell agreements 9,650 — 9,650 Total $ 110,979 $ — $ 110,979 Financial liabilities: Derivatives: Loan/lease interest rate swaps $ 9,068 $ — $ 9,068 Commodity swaps and options 16,951 — 16,951 Total derivatives 26,019 — 26,019 Repurchase agreements 4,342,941 — 4,342,941 Total $ 4,368,960 $ — $ 4,368,960 Gross Amounts Not Offset Net Amount Financial Collateral Net December 31, 2024 Financial assets: Derivatives: Counterparty H $ 36,286 $ (10,129) $ (26,157) $ — Counterparty F 15,505 (2,322) (11,759) 1,424 Counterparty B 22,338 (4,522) (17,816) — Counterparty E 14,219 (2,109) (12,100) 10 Other counterparties 12,981 (6,632) (6,325) 24 Total derivatives 101,329 (25,714) (74,157) 1,458 Resell agreements 9,650 — (9,650) — Total $ 110,979 $ (25,714) $ (83,807) $ 1,458 Financial liabilities: Derivatives: Counterparty H $ 10,129 $ (10,129) $ — $ — Counterparty F 2,322 (2,322) — — Counterparty B 4,522 (4,522) — — Counterparty E 2,109 (2,109) — — Other counterparties 6,937 (6,632) (305) — Total derivatives 26,019 (25,714) (305) — Repurchase agreements 4,342,941 — (4,342,941) — Total $ 4,368,960 $ (25,714) $ (4,343,246) $ — Information about financial instruments that are eligible for offset in the consolidated balance sheet as of December 31, 2023 is presented in the following tables. Gross Amount Gross Amount Net Amount December 31, 2023 Financial assets: Derivatives: Loan/lease interest rate swaps and caps $ 70,233 $ — $ 70,233 Commodity swaps and options 49,489 — 49,489 Foreign currency forward/option contracts 1 — 1 Total derivatives 119,723 — 119,723 Resell agreements 84,650 — 84,650 Total $ 204,373 $ — $ 204,373 Financial liabilities: Derivatives: Loan/lease interest rate swaps $ 20,293 $ — $ 20,293 Commodity swaps and options 20,999 — 20,999 Foreign currency forward contracts 19 — 19 Total derivatives 41,311 — 41,311 Repurchase agreements 4,127,188 — 4,127,188 Total $ 4,168,499 $ — $ 4,168,499 Gross Amounts Not Offset Net Amount Financial Collateral Net December 31, 2023 Financial assets: Derivatives: Counterparty H $ 36,551 $ (8,870) $ (27,170) $ 511 Counterparty F 31,202 (7,444) (22,954) 804 Counterparty B 23,829 (5,151) (18,472) 206 Counterparty E 13,271 (4,548) (8,723) — Other counterparties 14,870 (6,418) (7,520) 932 Total derivatives 119,723 (32,431) (84,839) 2,453 Resell agreements 84,650 — (84,650) — Total $ 204,373 $ (32,431) $ (169,489) $ 2,453 Financial liabilities: Derivatives: Counterparty H $ 8,870 $ (8,870) $ — $ — Counterparty F 7,444 (7,444) — — Counterparty B 5,151 (5,151) — — Counterparty E 4,548 (4,548) — — Other counterparties 15,298 (6,418) (8,580) 300 Total derivatives 41,311 (32,431) (8,580) 300 Repurchase agreements 4,127,188 — (4,127,188) — Total $ 4,168,499 $ (32,431) $ (4,135,768) $ 300 Repurchase Agreements . We utilize securities sold under agreements to repurchase to accommodate the business needs of our customers and to facilitate secured short-term funding needs. Securities sold under agreements to repurchase are stated at the amount of cash received in connection with the transaction. We monitor collateral levels on a continuous basis. We may be required to provide additional collateral based on the fair value of the underlying securities. Securities pledged as collateral under repurchase agreements are maintained with our safekeeping agents. The remaining contractual maturity of repurchase agreements in the consolidated balance sheets as of December 31, 2024 and December 31, 2023 is presented in the following tables. Remaining Contractual Maturity of the Agreements Overnight and Continuous Up to 30 Days 30-90 Days Greater than 90 Days Total December 31, 2024 Repurchase agreements: U.S. Treasury $ 2,170,482 $ — $ — $ — $ 2,170,482 Residential mortgage-backed securities 2,172,459 — — — 2,172,459 Total borrowings $ 4,342,941 $ — $ — $ — $ 4,342,941 Gross amount of recognized liabilities for repurchase agreements $ 4,342,941 Amounts related to agreements not included in offsetting disclosures above $ — December 31, 2023 Repurchase agreements: U.S. Treasury $ 3,300,662 $ — $ — $ — $ 3,300,662 Residential mortgage-backed securities 826,526 — — — 826,526 Total borrowings $ 4,127,188 $ — $ — $ — $ 4,127,188 Gross amount of recognized liabilities for repurchase agreements $ 4,127,188 Amounts related to agreements not included in offsetting disclosures above $ —

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The fair value of an asset or liability is the price that would be received to sell that asset or paid to transfer that liability in an orderly transaction occurring in the principal market (or most advantageous market in the absence of a principal market) for such asset or liability. In estimating fair value, we utilize valuation techniques that are consistent with the market approach, the income approach and/or the cost approach. Such valuation techniques are consistently applied. Inputs to valuation techniques include the assumptions that market participants would use in pricing an asset or liability. ASC Topic 820 establishes a fair value hierarchy for valuation inputs that gives the highest priority to quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. The fair value hierarchy is as follows: • Level 1 Inputs - Unadjusted quoted prices in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. • Level 2 Inputs - Inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. These might include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (such as interest rates, volatilities, prepayment speeds, credit risks, etc.) or inputs that are derived principally from or corroborated by market data by correlation or other means. • Level 3 Inputs - Unobservable inputs for determining the fair values of assets or liabilities that reflect an entity’s own assumptions about the assumptions that market participants would use in pricing the assets or liabilities. In general, fair value is based upon quoted market prices, where available. If such quoted market prices are not available, fair value is based upon internally developed models that primarily use, as inputs, observable market- based parameters. Valuation adjustments may be made to ensure that financial instruments are recorded at fair value. These adjustments may include amounts to reflect counterparty credit quality and our creditworthiness, among other things, as well as unobservable parameters. Any such valuation adjustments are applied consistently over time. Our valuation methodologies may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. While management believes our valuation methodologies are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different estimate of fair value at the reporting date. Furthermore, the reported fair value amounts have not been comprehensively revalued since the presentation dates, and therefore, estimates of fair value after the balance sheet date may differ significantly from the amounts presented herein. A more detailed description of the valuation methodologies used for assets and liabilities measured at fair value is set forth below. Transfers between levels of the fair value hierarchy are recognized on the actual date of the event or circumstances that caused the transfer, which generally coincides with our monthly and/or quarterly valuation process. Financial Assets and Financial Liabilities: Financial assets and financial liabilities measured at fair value on a recurring basis include the following: Securities Available for Sale . U.S. Treasury securities are reported at fair value utilizing Level 1 inputs. Other securities classified as available for sale are reported at fair value utilizing Level 2 inputs. For these securities, 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. We review the prices supplied by the independent pricing service, as well as their underlying pricing methodologies, for reasonableness and to ensure such prices are aligned with traditional pricing matrices. In general, we do not purchase investment portfolio securities that are esoteric or that have a complicated structure. Our entire portfolio consists of traditional investments, nearly all of which are U.S. Treasury obligations, federal agency bullet or mortgage pass-through securities, or general obligation or revenue based municipal bonds. Pricing for such instruments is fairly generic and is easily obtained. From time to time, we will validate prices supplied by the independent pricing service by comparison to prices obtained from third-party sources or derived using internal models. Trading Securities . U.S. Treasury securities and exchange-listed common stock are reported at fair value utilizing Level 1 inputs. Other securities classified as trading are reported at fair value utilizing Level 2 inputs in the same manner as described above for securities available for sale. Derivatives . Derivatives are generally reported at fair value utilizing Level 2 inputs. We utilize internal valuation methods with observable market data inputs to estimate the fair values of our outstanding interest rate, commodity and foreign currency derivative contracts. We also obtain dealer quotations and/or utilize third-party models for comparative purposes to assess the reasonableness of our model valuations. Though there has never been a significant discrepancy in the valuations, should such a significant discrepancy arise, we would obtain price verification from a third-party dealer. In cases where significant credit valuation adjustments are incorporated into the estimation of fair value, reported amounts are considered to have been derived utilizing Level 3 inputs. For purposes of potential valuation adjustments to our derivative positions, we evaluate the credit risk of our counterparties as well as ours. Accordingly, we have considered factors such as the likelihood of our default and the default of our counterparties, our net exposures and remaining contractual life, among other things, in determining if any fair value adjustments related to credit risk are required. Counterparty exposure is evaluated by netting positions that are subject to master netting arrangements, as well as considering the amount of collateral securing the position. We review our counterparty exposure on a regular basis, and, when necessary, appropriate business actions are taken to adjust the exposure. We also utilize this approach to estimate our own credit risk on derivative liability positions. To date, we have not realized any significant losses due to a counterparty’s inability to pay any net uncollateralized position. The change in value of derivative assets and derivative liabilities attributable to credit risk was not significant during the reported periods. The following tables summarize financial assets and financial liabilities measured at fair value on a recurring basis as of December 31, 2024 and 2023, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value: Level 1 Level 2 Level 3 Total 2024 Securities available for sale: U.S. Treasury $ 3,442,320 $ — $ — $ 3,442,320 Residential mortgage-backed securities — 6,997,902 — 6,997,902 States and political subdivisions — 4,560,224 — 4,560,224 Other — 43,179 — 43,179 Trading account securities: U.S. Treasury 33,910 — — 33,910 States and political subdivisions — — — — Derivative assets: Interest rate swaps, caps and floors — 79,122 — 79,122 Commodity swaps and options — 48,503 — 48,503 Foreign currency forward/option contracts — — — — Derivative liabilities: Interest rate swaps, caps and floors — 79,122 — 79,122 Commodity swaps and options — 47,304 — 47,304 Foreign currency forward/option contracts — — — — 2023 Securities available for sale: U.S. Treasury $ 4,927,589 $ — $ — $ 4,927,589 Residential mortgage-backed securities — 6,596,682 — 6,596,682 States and political subdivisions — 5,011,331 — 5,011,331 Other — 42,769 — 42,769 Trading account securities: U.S. Treasury 30,265 — — 30,265 States and political subdivisions — 1,452 — 1,452 Derivative assets: Interest rate swaps, caps and floors — 90,715 — 90,715 Commodity swaps and options — 70,710 — 70,710 Foreign currency forward contracts — 22 — 22 Derivative liabilities: Interest rate swaps, caps and floors — 90,525 — 90,525 Commodity swaps and options — 69,447 — 69,447 Foreign currency forward contracts — 19 — 19 Certain financial assets and financial liabilities are measured at fair value on a nonrecurring basis; that is, the instruments are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (for example, when there is evidence of impairment). Financial assets measured at fair value on a non-recurring basis during the reported periods include certain loans reported at the fair value of the underlying collateral if repayment is expected solely from the collateral. Collateral values are estimated using Level 2 inputs based on observable market data, typically in the case of real estate collateral, or Level 3 inputs based on customized discounting criteria, typically in the case of non-real estate collateral such as inventory, oil and gas reserves, accounts receivable, equipment or other business assets. The following table presents collateral dependent loans that were remeasured and reported at fair value through a specific allocation of the allowance for credit losses on loans based upon the fair value of the underlying collateral: 2024 2023 2022 Level 2 Carrying value before allocations $ 4,982 $ 19,719 $ 6,237 Specific (allocations) reversals of prior allocations (650) (3,391) (1,480) Fair value $ 4,332 $ 16,328 $ 4,757 Level 3 Carrying value before allocations $ 37,082 $ 15,465 $ 8,156 Specific (allocations) reversals of prior allocations (10,987) (2,344) 625 Fair value $ 26,095 $ 13,121 $ 8,781 Non-Financial Assets and Non-Financial Liabilities: We do not have any non-financial assets or non-financial liabilities measured at fair value on a recurring basis. From time to time, non-financial assets measured at fair value on a non-recurring basis may include certain foreclosed assets which, upon initial recognition, were remeasured and reported at fair value through a charge-off to the allowance for loan losses and certain foreclosed assets which, subsequent to their initial recognition, were remeasured at fair value through a write-down included in other non-interest expense. The fair value of a foreclosed asset is estimated using Level 2 inputs based on observable market data or Level 3 inputs based on customized discounting criteria. During the reported periods, all fair value measurements for foreclosed assets utilized Level 2 inputs. The following table presents foreclosed assets that were remeasured and reported at fair value: 2024 2023 2022 Foreclosed assets remeasured at initial recognition: Carrying value of foreclosed assets prior to remeasurement $ 19,297 $ — $ 239 Charge-offs recognized in the allowance for credit losses on loans (3,797) — — Fair value $ 15,500 $ — $ 239 Charge-offs recognized upon loan foreclosures are generally offset by general or specific allocations of the allowance for credit losses on loans and generally do not, and did not during the reported periods, significantly impact our credit loss expense. Regulatory guidelines require us to reevaluate the fair value of other real estate owned on at least an annual basis. While our policy is to comply with the regulatory guidelines, our general practice is to reevaluate the fair value of collateral supporting collateral dependent loans on a quarterly basis. Thus, appraisals are generally not considered to be outdated, and we typically do not make any adjustments to the appraised values. ASC Topic 825, “Financial Instruments,” requires disclosure of the fair value of financial assets and financial liabilities, including those financial assets and financial liabilities that are not measured and reported at fair value on a recurring basis or non-recurring basis. The estimated fair value approximates carrying value for cash and cash equivalents, accrued interest and the cash surrender value of life insurance policies. The methodologies for other financial assets and financial liabilities that are not measured and reported at fair value on a recurring basis or non-recurring basis are discussed below: Loans . The estimated fair value approximates carrying value for variable-rate loans that reprice frequently and with no significant change in credit risk. The fair value of fixed-rate loans and variable-rate loans which reprice on an infrequent basis is estimated by discounting future cash flows using the current interest rates at which similar loans with similar terms would be made to borrowers of similar credit quality. An overall valuation adjustment is made for specific credit risks as well as general portfolio credit risk. Deposits . The estimated fair value approximates carrying value for demand deposits. The fair value of fixed-rate deposit liabilities with defined maturities is estimated by discounting future cash flows using the interest rates currently offered for deposits of similar remaining maturities. The estimated fair value of deposits does not take into account the value of our long-term relationships with depositors, commonly known as core deposit intangibles, which are separate intangible assets, and not considered financial instruments. Nonetheless, we would likely realize a core deposit premium if our deposit portfolio were sold in the principal market for such deposits. Borrowed Funds . The estimated fair value approximates carrying value for short-term borrowings. The fair value of long-term fixed-rate borrowings is estimated using quoted market prices, if available, or by discounting future cash flows using current interest rates for similar financial instruments. The estimated fair value approximates carrying value for variable-rate junior subordinated deferrable interest debentures that reprice quarterly. Loan Commitments, Standby and Commercial Letters of Credit . Our lending commitments have variable interest rates and “escape” clauses if the customer’s credit quality deteriorates. Therefore, the fair values of these items are not significant and are not included in the following table. The estimated fair values of financial instruments that are reported at amortized cost in our consolidated balance sheets, segregated by the level of valuation inputs within the fair value hierarchy utilized to measure fair value, were as follows: December 31, 2024 December 31, 2023 Carrying Estimated Carrying Estimated Financial assets: Level 2 inputs: Cash and cash equivalents $ 10,234,258 $ 10,234,258 $ 8,687,276 $ 8,687,276 Securities held to maturity 3,533,775 3,360,546 3,619,428 3,532,044 Accrued interest receivable 236,591 236,591 251,385 251,385 Level 3 inputs: Loans, net 20,484,662 20,066,512 18,578,255 18,117,369 Financial liabilities: Level 2 inputs: Deposits 42,722,748 42,712,907 41,920,568 41,903,580 Federal funds purchased 21,975 21,975 14,200 14,200 Repurchase agreements 4,342,941 4,342,941 4,127,188 4,127,188 Junior subordinated deferrable interest debentures 123,184 123,712 123,127 123,712 Subordinated notes 99,648 98,453 99,491 96,071 Accrued interest payable 58,870 58,870 61,222 61,222 Under ASC Topic 825, entities may choose to measure eligible financial instruments at fair value at specified election dates. The fair value measurement option (i) may be applied instrument by instrument, with certain exceptions, (ii) is generally irrevocable and (iii) is applied only to entire instruments and not to portions of instruments. Unrealized gains and losses on items for which the fair value measurement option has been elected must be reported in earnings at each subsequent reporting date. During the reported periods, we had no financial instruments measured at fair value under the fair value measurement option.

Operating Segments

Operating Segments	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Operating Segments	Operating Segments We are managed under a matrix organizational structure whereby our two primary operating segments, Banking and Frost Wealth Advisors, overlap a regional reporting structure. The regions are primarily based upon geographic location and include Austin, Dallas, Fort Worth, Gulf Coast (which includes Corpus Christi and the Rio Grande Valley), Houston, Permian Basin, San Antonio and Statewide. We are primarily managed based on the line of business structure. In that regard, all regions have the same lines of business, which have the same product and service offerings, have similar types and classes of customers and utilize similar service delivery methods. Pricing guidelines for products and services are the same across all regions. The regional reporting structure is primarily a means to scale the lines of business to provide a local, community focus for customer relations and business development. Banking and Frost Wealth Advisors are delineated by the products and services that each segment offers. The Banking operating segment includes both commercial and consumer banking services and Frost Insurance Agency. Commercial banking services are provided to corporations and other business clients and include a wide array of lending and cash management products. Consumer banking services include direct lending and depository services. Frost Insurance Agency provides insurance brokerage services to individuals and businesses covering corporate and personal property and casualty products, as well as group health and life insurance products. The Frost Wealth Advisors operating segment includes fee-based services within private trust, retirement services, and financial management services, including personal wealth management and securities brokerage services. A third operating segment, Non-Banks, is for the most part the parent holding company, as well as certain other insignificant non-bank subsidiaries of the parent that, for the most part, have little or no activity. Non-banks also includes certain eliminating amounts. The parent company’s principal activities include the direct and indirect ownership of our banking and non-banking subsidiaries and the issuance of debt and equity. Our principal source of revenue is dividends from our subsidiaries. The accounting policies of each reportable segment are the same as those of our consolidated entity except for the following items, which impact the Banking and Frost Wealth Advisors segments: (i) expenses for consolidated back-office operations and general overhead-type expenses such as executive administration, accounting and internal audit are allocated to operating segments based on estimated uses of those services, and (ii) the parent company records the tax expense or benefit necessary to reconcile to the consolidated total. Our chief executive officer is our chief operating decision maker. We use a match-funded transfer pricing process to allocate costs, capital and resources to each operating segment. The process helps us to (i) identify the cost or opportunity value of funds within each business segment, (ii) measure the profitability of a particular business segment by relating appropriate costs to revenues, (iii) evaluate each business segment in a manner consistent with its economic impact on consolidated earnings, and (iv) enhance asset and liability pricing decisions. Our chief executive officer reviews actual net income versus budgeted net income to assess segment performance on a monthly basis and to make decisions about allocating capital and personnel to the segments. Financial results by operating segment, including significant expense categories provided to the chief operating decision maker, are detailed below. Certain prior period amounts have been reclassified to conform to the current presentation. Frost Wealth Advisors excludes off-balance-sheet managed and custody assets with a total fair value of $51.4 billion, $47.2 billion and $42.9 billion at December 31, 2024, 2023 and 2022. Banking Frost Non-Banks Consolidated 2024 Interest income $ 2,382,675 $ 7,962 $ — $ 2,390,637 Interest expense 772,075 421 13,529 786,025 Net interest income (expense) 1,610,600 7,541 (13,529) 1,604,612 Credit loss expense 64,985 — — 64,985 Net interest income after credit loss expense 1,545,615 7,541 (13,529) 1,539,627 Non-interest income: Trust and investment management fees — 167,448 (2,178) 165,270 Service charges on deposit accounts 106,217 13 — 106,230 Insurance commissions and fees 61,269 — — 61,269 Interchange and card transaction fees 21,017 — — 21,017 Other charges, commissions and fees 30,626 22,717 5 53,348 Net gain (loss) on securities transactions (96) — — (96) Other 45,790 6,011 259 52,060 Total non-interest income 264,823 196,189 (1,914) 459,098 Non-interest expense: Salaries and wages 544,843 74,928 1,623 621,394 Employee benefits 109,431 12,911 104 122,446 Net occupancy 115,136 13,615 — 128,751 Technology, furniture and equipment 142,517 5,764 206 148,487 Deposit insurance 37,203 66 — 37,269 Other 189,700 49,790 4,921 244,411 Total non-interest expense 1,138,830 157,074 6,854 1,302,758 Income (loss) before income taxes 671,608 46,656 (22,297) 695,967 Income tax expense (benefit) 110,524 9,798 (6,897) 113,425 Net income (loss) 561,084 36,858 (15,400) 582,542 Preferred stock dividends — — 6,675 6,675 Net income (loss) available to common shareholders $ 561,084 $ 36,858 $ (22,075) $ 575,867 Revenues from (expenses to) external customers $ 1,875,423 $ 203,730 $ (15,443) $ 2,063,710 Average assets (in millions) $ 49,621 $ 64 $ 9 $ 49,694 Banking Frost Non-Banks Consolidated 2023 Interest income $ 2,209,659 $ 8,057 $ — $ 2,217,716 Interest expense 647,218 437 11,397 659,052 Net interest income (expense) 1,562,441 7,620 (11,397) 1,558,664 Credit loss expense 46,171 — — 46,171 Net interest income after credit loss expense 1,516,270 7,620 (11,397) 1,512,493 Non-interest income: Trust and investment management fees — 155,278 (1,963) 153,315 Service charges on deposit accounts 93,478 26 — 93,504 Insurance commissions and fees 58,271 — — 58,271 Interchange and card transaction fees 19,419 — — 19,419 Other charges, commissions and fees 30,217 18,809 — 49,026 Net gain (loss) on securities transactions 66 — — 66 Other 49,868 4,793 280 54,941 Total non-interest income 251,319 178,906 (1,683) 428,542 Non-interest expense: Salaries and wages 480,083 66,070 1,565 547,718 Employee benefits 103,427 11,776 103 115,306 Net occupancy 109,953 14,443 — 124,396 Technology, furniture and equipment 129,042 6,054 190 135,286 Deposit insurance 76,535 54 — 76,589 Other 178,784 46,081 4,502 229,367 Total non-interest expense 1,077,824 144,478 6,360 1,228,662 Income (loss) before income taxes 689,765 42,048 (19,440) 712,373 Income tax expense (benefit) 111,145 8,830 (5,575) 114,400 Net income (loss) 578,620 33,218 (13,865) 597,973 Preferred stock dividends — — 6,675 6,675 Net income (loss) available to common shareholders $ 578,620 $ 33,218 $ (20,540) $ 591,298 Revenues from (expenses to) external customers $ 1,813,760 $ 186,526 $ (13,080) $ 1,987,206 Average assets (in millions) $ 49,536 $ 59 $ 9 $ 49,604 Banking Frost Non-Banks Consolidated 2022 Interest income $ 1,470,947 $ 4,774 $ — $ 1,475,721 Interest expense 175,480 129 8,829 184,438 Net interest income (expense) 1,295,467 4,645 (8,829) 1,291,283 Credit loss expense 3,000 — — 3,000 Net interest income after credit loss expense 1,292,467 4,645 (8,829) 1,288,283 Non-interest income: Trust and investment management fees — 156,751 (2,072) 154,679 Service charges on deposit accounts 91,851 40 — 91,891 Insurance commissions and fees 53,210 — — 53,210 Interchange and card transaction fees 18,231 — — 18,231 Other charges, commissions and fees 24,520 17,070 — 41,590 Net gain (loss) on securities transactions — — — — Other 43,064 2,013 140 45,217 Total non-interest income 230,876 175,874 (1,932) 404,818 Non-interest expense: Salaries and wages 430,660 59,988 1,448 492,096 Employee benefits 78,178 10,273 157 88,608 Net occupancy 98,916 13,579 — 112,495 Technology, furniture and equipment 115,257 5,341 173 120,771 Deposit insurance 15,569 34 — 15,603 Other 147,841 42,794 4,066 194,701 Total non-interest expense 886,421 132,009 5,844 1,024,274 Income (loss) before income taxes 636,922 48,510 (16,605) 668,827 Income tax expense (benefit) 85,127 10,187 (5,637) 89,677 Net income (loss) 551,795 38,323 (10,968) 579,150 Preferred stock dividends — — 6,675 6,675 Net income (loss) available to common shareholders $ 551,795 $ 38,323 $ (17,643) $ 572,475 Revenues from (expenses to) external customers $ 1,526,343 $ 180,519 $ (10,761) $ 1,696,101 Average assets (in millions) $ 51,448 $ 57 $ 8 $ 51,513

Condensed Financial Statements

Condensed Financial Statements of Parent Company	12 Months Ended
	Dec. 31, 2024
Condensed Financial Information Disclosure [Abstract]
Condensed Financial Statements of Parent Company	Condensed Financial Statements of Parent Company Condensed financial statements pertaining only to Cullen/Frost Bankers, Inc. are presented below. Investments in subsidiaries are stated using the equity method of accounting. Condensed Balance Sheets December 31, 2024 2023 Assets: Cash $ 334,512 $ 350,525 Total cash and cash equivalents 334,512 350,525 Investment in subsidiaries 3,828,890 3,625,951 Accrued interest receivable and other assets 1,231 1,233 Total assets $ 4,164,633 $ 3,977,709 Liabilities: Junior subordinated deferrable interest debentures, net of unamortized issuance costs $ 123,184 $ 123,127 Subordinated notes, net of unamortized issuance costs 99,648 99,491 Accrued interest payable and other liabilities 43,213 38,644 Total liabilities 266,045 261,262 Shareholders’ Equity 3,898,588 3,716,447 Total liabilities and shareholders’ equity $ 4,164,633 $ 3,977,709 Condensed Statements of Income Year Ended December 31, 2024 2023 2022 Income: Dividend income paid by Frost Bank $ 262,214 $ 279,679 $ 51,711 Dividend income paid by non-banks 268 255 109 Interest and other income — 1,929 — Total income 262,482 281,863 51,820 Expenses: Interest expense 13,529 13,304 8,829 Salaries and employee benefits 1,727 1,668 1,605 Other 7,304 6,653 6,316 Total expenses 22,560 21,625 16,750 Income before income taxes and equity in undistributed earnings of subsidiaries 239,922 260,238 35,070 Income tax benefit 6,896 5,974 5,641 Equity in undistributed earnings of subsidiaries 335,724 331,761 538,439 Net income 582,542 597,973 579,150 Preferred stock dividends 6,675 6,675 6,675 Net income available to common shareholders $ 575,867 $ 591,298 $ 572,475 Condensed Statements of Cash Flows Year Ended December 31, 2024 2023 2022 Operating Activities: Net income $ 582,542 $ 597,973 $ 579,150 Adjustments to reconcile net income to net cash provided by operating activities: Equity in undistributed earnings of subsidiaries (335,724) (331,761) (538,439) Stock-based compensation 934 880 720 Net tax benefit from stock-based compensation 463 331 472 Net change in other assets and other liabilities 4,322 19,867 (15,249) Net cash from operating activities 252,537 287,290 26,654 Investing Activities: Net cash from investing activities — — — Financing Activities: Proceeds from stock option exercises 22,643 9,299 16,659 Proceeds from stock-based compensation activities of subsidiaries 18,829 23,710 17,602 Purchase of treasury stock (60,901) (42,720) (4,391) Cash dividends paid on preferred stock (6,675) (6,675) (6,675) Cash dividends paid on common stock (242,446) (232,323) (209,780) Net cash from financing activities (268,550) (248,709) (186,585) Net change in cash and cash equivalents (16,013) 38,581 (159,931) Cash and cash equivalents at beginning of year 350,525 311,944 471,875 Cash and cash equivalents at end of year $ 334,512 $ 350,525 $ 311,944

Accounting Standards Updates

Accounting Standards Updates	12 Months Ended
	Dec. 31, 2024
Accounting Standards Update and Change in Accounting Principle [Abstract]
Accounting Standards Updates	Accounting Standards Updates ASU 2022-01, “Derivatives and Hedging (Topic 815): Fair Value Hedging - Portfolio Layer Method.” Under prior guidance, entities can apply the last-of-layer hedging method to hedge the exposure of a closed portfolio of prepayable financial assets to fair value changes due to changes in interest rates for a portion of the portfolio that is not expected to be affected by prepayments, defaults, and other events affecting the timing and amount of cash flows. ASU 2022-01 expands the last-of-layer method, which permits only one hedge layer, to allow multiple hedged layers of a single closed portfolio. To reflect that expansion, the last-of-layer method is renamed the portfolio layer method. ASU 2022-01 also (i) expands the scope of the portfolio layer method to include non-prepayable financial assets, (ii) specifies eligible hedging instruments in a single-layer hedge, (iii) provides additional guidance on the accounting for and disclosure of hedge basis adjustments under the portfolio layer method and (iv) specifies how hedge basis adjustments should be considered when determining credit losses for the assets included in the closed portfolio. ASU 2022-01 became effective for us in 2023. The adoption of ASU 2022-01 did not have a significant impact on our financial statements. ASU 2022-02, “Financial Instruments - Credit Losses (Topic 326): Troubled Debt Restructurings and Vintage Disclosures.” ASU 2022-02 eliminates the accounting guidance for troubled debt restructurings in Accounting Standards Codification (“ASC”) Subtopic 310-40, Receivables - Troubled Debt Restructurings by Creditors, while enhancing disclosure requirements for certain loan refinancings and restructurings by creditors 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 within the scope of ASC Subtopic 3126-20, Financial Instruments - Credit Losses - Measured at Amortized Cost. ASU 2022-02 became effective for us in 2023. The adoption of ASU 2022-02 did not have a significant impact on our financial statements. ASU 2022-03, “Fair Value Measurement (Topic 820): Fair Value Measurement of Equity Securities Subject to Contractual Sale Restrictions.” ASU 2022-03 clarifies that a contractual restriction on the sale of an equity security is not considered part of the unit of account of the equity security and, therefore, is not considered in measuring fair value. ASU 2022-03 also clarifies that an entity cannot, as a separate unit of account, recognize and measure a contractual sale restriction and requires certain new disclosures for equity securities subject to contractual sale restrictions. ASU 2022-03 became effective for us in 2024 and did not have a significant effect on our financial statements. ASU 2023-01, “Leases (Topic 842): Common Control Arrangements.” ASU 2023-01 requires entities to amortize leasehold improvements associated with common control leases over the useful life to the common control group. ASU 2023-01 also provides certain practical expedients applicable to private companies and not-for-profit organizations. ASU 2023-01 became effective for us in 2024 and did not have a significant effect on our financial statements. ASU No. 2023-02, “Investments - Equity Method and Joint Ventures (Topic 323): Accounting for Investments in Tax Credit Structures Using the Proportional Amortization Method.” ASU 2023-02 is intended to improve the accounting and disclosures for investments in tax credit structures. ASU 2023-02 allows entities to elect to account for qualifying tax equity investments using the proportional amortization method, regardless of the program giving rise to the related income tax credits. Previously, this method was only available for qualifying tax equity investments in low-income housing tax credit structures. ASU 2023-02 became effective for us in 2024 and did not have a significant effect on our financial statements. ASU No. 2023-07, “Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures.” ASU 2023-07 expands segment disclosure requirements for public entities to require disclosure of significant segment expenses and other segment items on an annual and interim basis and to provide in interim periods all disclosures about a reportable segment’s profit or loss and assets that are currently required annually. ASU 2023-07 became effective for our annual financial statements in 2024 (see Note 17 - Operating Segments) and will be effective for interim periods within fiscal years in 2025. ASU No. 2023-09, “Income Taxes (Topic 740): Improvements to Income Tax Disclosures.” ASU 2023-09 requires public business entities to disclose in their rate reconciliation table additional categories of information about federal, state and foreign income taxes and to provide more details about the reconciling items in some categories if items meet a quantitative threshold. ASU 2023-09 also requires all entities to disclose income taxes paid, net of refunds, disaggregated by federal, state and foreign taxes for annual periods and to disaggregate the information by jurisdiction based on a quantitative threshold, among other things. ASU 2023-09 is effective for us in 2025 and is not expected to have a significant impact on our financial statements. ASU No. 2024-03, “Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses.”

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net income (loss)	$ 582,542	$ 597,973	$ 579,150

Insider Trading Arrangements

Insider Trading Arrangements	12 Months Ended
	Dec. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Insider Trading Policies and Pr

Insider Trading Policies and Procedures	12 Months Ended
	Dec. 31, 2024
Insider Trading Policies and Procedures [Line Items]
Insider Trading Policies and Procedures Adopted	true

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Nature Of Operations	Nature of Operations . Cullen/Frost Bankers, Inc. (“Cullen/Frost”) is a financial holding company and a bank holding company headquartered in San Antonio, Texas that provides, through its subsidiaries, a broad array of products and services throughout numerous Texas markets. The terms “Cullen/Frost,” “the Corporation,” “we,” “us” and “our” mean Cullen/Frost Bankers, Inc. and its subsidiaries, when appropriate. In addition to general commercial and consumer banking, other products and services offered include trust and investment management, insurance, brokerage, mutual funds, leasing, treasury management, capital markets advisory and item processing.
Basis of Presentation	Basis of Presentation. The consolidated financial statements include the accounts of Cullen/Frost and all other entities in which Cullen/Frost has a controlling financial interest. All significant intercompany balances and transactions have been eliminated in consolidation. The accounting and financial reporting policies we follow conform, in all material respects, to accounting principles generally accepted in the United States and to general practices within the financial services industry. We determine whether we have a controlling financial interest in an entity by first evaluating whether the entity is a voting interest entity or a variable interest entity (“VIE”) under accounting principles generally accepted in the United States. Voting interest entities are entities in which the total equity investment at risk is sufficient to enable the entity to finance itself independently and provides the equity holders with the obligation to absorb losses, the right to receive residual returns and the right to make decisions about the entity’s activities. We consolidate voting interest entities in which we have all, or at least a majority of, the voting interest. As defined in applicable accounting standards, VIEs are entities that lack one or more of the characteristics of a voting interest entity. A controlling financial interest in a VIE is present when an enterprise has both the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and an obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. The enterprise with a controlling financial interest, known as the primary beneficiary, consolidates the VIE. Our wholly-owned subsidiary, Cullen/Frost Capital Trust II, is a VIE for which we are not the primary beneficiary and, as such, its accounts are not included in our consolidated financial statements. Acquisitions are accounted for using the purchase method with the operating results of the acquired companies included with our results of operations since their respective dates of acquisition.
Use of Estimates	Use of Estimates . The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates. The allowance for credit losses on loans and off-balance-sheet credit exposures, the fair values of financial instruments and the status of contingencies are particularly subject to change.
Concentrations and Restrictions on Cash and Cash Equivalents	Concentrations and Restrictions on Cash and Cash Equivalents . We maintain deposits with other financial institutions in amounts that exceed federal deposit insurance coverage. Furthermore, federal funds sold are essentially uncollateralized loans to other financial institutions. Management regularly evaluates the credit risk associated with the counterparties to these transactions and believes that we are not exposed to any significant credit risks on cash and cash equivalents. As of December 31, 2024 and 2023, we had $350 thousand and $8.6 million in cash collateral on deposit with other financial institution counterparties to interest rate swap transactions.
Cash Flow Reporting	Cash Flow Reporting . Cash and cash equivalents include cash, deposits with other financial institutions that have an initial maturity of less than 90 days when acquired by us, federal funds sold and resell agreements. Net cash flows are reported for loans, deposit transactions and short-term borrowings. Additional cash flow information was as follows: Year Ended December 31, 2024 2023 2022 Cash paid for interest $ 788,377 $ 616,274 $ 169,020 Cash paid for income tax 122,000 118,000 100,000 Significant non-cash transactions: Unsettled securities transactions 501,587 1,452 94,884 Loans foreclosed and transferred to other real estate owned and foreclosed assets 19,297 — 239 Right-of-use lease assets obtained in exchange for lessee operating lease liabilities 15,044 15,259 31,787
Repurchase/Resell Agreements	Repurchase/Resell Agreements. We purchase certain securities under agreements to resell. The amounts advanced under these agreements represent short-term loans and are reflected as assets in the accompanying consolidated balance sheets. The securities underlying these agreements are book-entry securities. We also sell certain securities under agreements to repurchase. The agreements are treated as collateralized financing transactions and the obligations to repurchase securities sold are reflected as a liability in the accompanying consolidated balance sheets. The dollar amount of the securities underlying the agreements remains in the asset accounts.
Securities	Securities. Securities are classified as held to maturity and carried at amortized cost when management has the positive intent and ability to hold them until maturity. Securities to be held for indefinite periods of time are classified as available for sale and carried at fair value, with the unrealized holding gains and losses (those for which no allowance for credit losses are recorded) reported as a component of other comprehensive income, net of tax. Securities held for resale in anticipation of short-term market movements are classified as trading and are carried at fair value, with changes in unrealized holding gains and losses included in income. Management determines the appropriate classification of securities at the time of purchase. Securities with limited marketability, such as stock in the Federal Reserve Bank and the Federal Home Loan Bank, are carried at cost. Interest income on securities includes amortization of purchase premiums and discounts. Premiums and discounts on securities are generally amortized using the interest method with a constant effective yield without anticipating prepayments, except for mortgage-backed securities where prepayments are anticipated. Premiums on callable securities are amortized to their earliest call date. A security is placed on non-accrual status if (i) principal or interest has been in default for a period of 90 days or more or (ii) full payment of principal and interest is not expected. Interest accrued but not received for a security placed on non-accrual status is reversed against interest income. Gains and losses on sales are recorded on the trade date and are derived from the amortized cost of the security sold.
Loans	Loans . Loans are reported at the principal balance outstanding net of unearned discounts. Interest income on loans is reported on the level-yield method and includes amortization of deferred loan fees and costs over the terms of the individual loans to which they relate, or, in certain cases, over the average expected term for loans where deferred fees and costs are accounted for on a pooled basis. Net loan commitment fees or costs for commitment periods greater than one year are deferred and amortized into fee income or other expense on a straight-line basis over the commitment period. Income on direct financing leases is recognized on a basis that achieves a constant periodic rate of return on the outstanding investment. Further information regarding our accounting policies related to past due loans, non-accrual loans, and loan modifications to borrowers experiencing financial difficulty is presented in Note 3 - Loans.
Credit Loss, Financial Instrument	Allowance For Credit Losses - Held-to-Maturity Securities. The allowance for credit losses on held-to-maturity securities is a contra-asset valuation account, calculated in accordance with Accounting Standards Codification (“ASC”) Topic 326 (“ASC 326”), that is deducted from the amortized cost basis of held-to-maturity securities to present management's best estimate of the net amount expected to be collected. Held-to-maturity securities are charged-off against the allowance when deemed uncollectible by management. Adjustments to the allowance are reported in our income statement as a component of credit loss expense. Management measures expected credit losses on held-to-maturity securities on a collective basis by major security type with each type sharing similar risk characteristics and considers historical credit loss information that is adjusted for current conditions and reasonable and supportable forecasts. Management has made the accounting policy election to exclude accrued interest receivable on held-to-maturity securities from the estimate of credit losses. Further information regarding our policies and methodology used to estimate the allowance for credit losses on held-to-maturity securities is presented in Note 2 - Securities. Allowance For Credit Losses - Available-for-Sale Securities. For available-for-sale securities in an unrealized loss position, we first assess whether (i) we intend to sell or (ii) it is more likely than not that we will be required to sell the security before recovery of its amortized cost basis. If either case is affirmative, any previously recognized allowances are charged-off and the security's amortized cost is written down to fair value through income. If neither case is affirmative, the security is evaluated to determine whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, management considers the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency and any adverse conditions specifically related to the security, among other factors. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the security are compared to the amortized cost basis of the security. If the present value of cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded for the credit loss, limited by the amount that the fair value is less than the amortized cost basis. Any impairment that has not been recorded through an allowance for credit losses is recognized in other comprehensive income. Adjustments to the allowance are reported in our income statement as a component of credit loss expense. Management has made the accounting policy election to exclude accrued interest receivable on available-for-sale securities from the estimate of credit losses. Available-for-sale securities are charged-off against the allowance or, in the absence of any allowance, written down through income when deemed uncollectible by management or when either of the aforementioned criteria regarding intent or requirement to sell is met.
Off-Balance-Sheet Credit Exposure	Allowance For Credit Losses - Off-Balance-Sheet Credit Exposures. The allowance for credit losses on off-balance-sheet credit exposures is a liability account, calculated in accordance with ASC 326, representing expected credit losses over the contractual period for which we are exposed to credit risk resulting from a contractual obligation to extend credit. No allowance is recognized if we have the unconditional right to cancel the obligation. The allowance is reported as a component of accrued interest payable and other liabilities in our consolidated balance sheets. Adjustments to the allowance are reported in our income statement as a component of credit loss expense. Further information regarding our policies and methodology used to estimate the allowance for credit losses on off-balance-sheet credit exposures is presented in Note 7 - Off-Balance-Sheet Arrangements, Commitments, Guarantees and Contingencies. Allowance For Credit Losses - Off-Balance-Sheet Credit Exposures. The allowance for credit losses on off-balance-sheet credit exposures is a liability account, calculated in accordance with ASC 326, representing expected credit losses over the contractual period for which we are exposed to credit risk resulting from a contractual obligation to extend credit. No allowance is recognized if we have the unconditional right to cancel the obligation. Off-balance-sheet credit exposures primarily consist of amounts available under outstanding lines of credit and letters of credit detailed in the table above. For the period of exposure, the estimate of expected credit losses considers both the likelihood that funding will occur and the amount expected to be funded over the estimated remaining life of the commitment or other off-balance-sheet exposure. The likelihood and expected amount of funding are based on historical utilization rates. The amount of the allowance represents management's best estimate of expected credit losses on commitments expected to be funded over the contractual life of the commitment. Estimating credit losses on amounts expected to be funded uses the same methodology as described for loans in Note 3 - Loans as if such commitments were funded. This methodology was also impacted by the model updates during 2024 and 2023, as described in Note 3 - Loans. For 2024, the overall approximate impact of the model updates was a $1.8 million increase in modeled expected credit losses for off-balance-sheet credit exposures ($1.6 million related to consumer and other loan commitments and $211 thousand related to non-owner-occupied commercial real estate loan commitments). For 2023, the overall approximate impact of the model updates was a $19.0 million decrease in modeled expected credit losses for off-balance-sheet credit exposures, though the impact of this decrease was largely offset with discretionary qualitative adjustments.
Premises and Equipment	Premises and Equipment. Land is carried at cost. Building and improvements, and furniture and equipment are carried at cost, less accumulated depreciation, computed principally by the straight-line method based on the estimated useful lives of the related property. Leasehold improvements are generally depreciated over the lesser of the term of the respective leases or the estimated useful lives of the improvements. We lease certain office facilities and office equipment under operating leases. We also own certain office facilities which we lease to outside parties under operating lessor leases; however, such leases are not significant. For operating leases other than those considered to be short-term, we recognize lease right-of-use assets and related lease liabilities. Such amounts are reported as components of premises and equipment and accrued interest payable and other liabilities, respectively, on our accompanying consolidated balance sheet. We do not recognize short-term operating leases on our balance sheet. A short-term operating lease has an original term of 12 months or less and does not have a purchase option that is likely to be exercised. In recognizing lease right-of-use assets and related lease liabilities, we account for lease and non-lease components (such as taxes, insurance, and common area maintenance costs) separately as such amounts are generally readily determinable under our lease contracts. Lease payments over the expected term are discounted using our incremental borrowing rate referenced to the Federal Home Loan Bank Secure Connect advance rates for borrowings of similar term. We also consider renewal and termination options in the determination of the term of the lease. If it is reasonably certain that a renewal or termination option will be exercised, the effects of such options are included in the determination of the expected lease term. Generally, we cannot be reasonably certain about whether or not we will renew a lease until such time the lease is within the last two years of the existing lease term. However, renewal options related to our regional headquarters facilities or operations centers are evaluated on a case-by-case basis, typically in advance of such time frame. When we are reasonably certain that a renewal option will be exercised, we measure/remeasure the right-of-use asset and related lease liability using the lease payments specified for the renewal period or, if such amounts are unspecified, we generally assume an increase (evaluated on a case-by-case basis in light of prevailing market conditions) in the lease payment over the final period of the existing lease term.
Foreclosed Assets	Foreclosed Assets . Assets acquired through or instead of loan foreclosure are held for sale and are initially recorded at fair value less estimated selling costs when acquired, establishing a new cost basis. Write-downs occurring at acquisition are charged against the allowance for credit losses on loans. Foreclosed assets are included in other assets in the accompanying consolidated balance sheets and totaled $14.1 million and $725 thousand at December 31, 2024 and 2023. Regulatory guidelines require us to reevaluate the fair value of foreclosed assets on at least an annual basis. Our policy is to comply with the regulatory guidelines. If the fair value of the asset declines, a write-down is recorded through other non-interest expense along with other expenses related to maintaining the properties. The valuation of foreclosed assets is subjective in nature and may be adjusted in the future because of changes in economic conditions. There were no write-downs of foreclosed assets in 2024, 2023, or 2022. There were no significant concentrations of any properties, to which the aforementioned write-downs relate, in any single geographic region.
Revenue Recognition	Revenue Recognition . In general, for revenue not associated with financial instruments, guarantees and lease contracts, we apply the following steps when recognizing revenue from contracts with customers: (i) identify the contract, (ii) identify the performance obligations, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations and (v) recognize revenue when a performance obligation is satisfied. Our contracts with customers are generally short term in nature, typically due within one year or less or cancellable by us or our customer upon a short notice period. Performance obligations for our customer contracts are generally satisfied at a single point in time, typically when the transaction is complete, or over time. For performance obligations satisfied over time, we primarily use the output method, directly measuring the value of the products/services transferred to the customer, to determine when performance obligations have been satisfied. We typically receive payment from customers and recognize revenue concurrent with the satisfaction of our performance obligations. In most cases, this occurs within a single financial reporting period. For payments received in advance of the satisfaction of performance obligations, revenue recognition is deferred until such time as the performance obligations have been satisfied. In cases where we have not received payment despite satisfaction of our performance obligations, we accrue an estimate of the amount due in the period our performance obligations have been satisfied. For contracts with variable components, only amounts for which collection is probable are accrued. We generally act in a principal capacity, on our own behalf, in most of our contracts with customers. In such transactions, we recognize revenue and the related costs to provide our services on a gross basis in our financial statements. In some cases, we act in an agent capacity, deriving revenue through assisting other entities in transactions with our customers. In such transactions, we recognize revenue and the related costs to provide our services on a net basis in our financial statements. These transactions recognized on a net basis primarily relate to insurance and brokerage commissions and fees derived from our customers' use of various interchange and ATM/debit card networks.
Stock Based Compensation	Share-Based Payments . Compensation expense for stock options, non-vested stock awards/stock units and deferred stock units is based on the fair value of the award on the measurement date, which, for us, is the date of the grant and is recognized ratably over the service period of the award. Compensation expense for performance stock units is based on the fair value of the award on the measurement date, which, for us, is the date of the grant and is recognized over the service period of the award based upon the probable number of units expected to vest. The fair value of stock options is estimated using a binomial lattice-based valuation model. The fair value of non-vested stock awards/stock units and deferred stock units is generally the market price of our stock on the date of grant. The fair value of performance stock units is generally the market price of our stock on the date of grant discounted by the present value of the dividends expected to be paid on our common stock during the service period of the award because dividend equivalent payments on performance stock units are deferred until such time that the units vest and shares are issued. The impact of forfeitures of share-based payment awards on compensation expense is recognized as forfeitures occur. We have three active stock compensation plans (the 2007 Outside Directors Incentive Plan, the 2015 Omnibus Incentive Plan, and the 2024 Equity Incentive Plan). All of the plans have been approved by our shareholders. The 2024 Equity Incentive Plan (the “2024 Plan”) was approved by our shareholders on April 24, 2024 to replace the 2015 Omnibus Incentive Plan (the “2015 Plan”). Under the 2024 Plan, shareholders approved the issuance, pursuant to the plan, of 2,576,038 shares of our common stock. This amount included 2,350,000 newly authorized shares and the 226,038 shares remaining available for issuance under the superseded 2015 Plan. The 2015 Plan had previously superseded the 2007 Outside Directors Incentive Plan (the “2007 Directors Plan”) and the 2005 Omnibus Incentive Plan, which is no longer active. Our stock compensation plans were established to (i) motivate superior performance by means of performance-related incentives, (ii) encourage and provide for the acquisition of an ownership interest in our company by employees and non-employee directors and (iii) enable us to attract and retain qualified and competent persons as employees and to serve as members of our board of directors. Under the 2024 Plan, we may grant, among other things, nonqualified stock options, incentive stock options, stock awards, stock appreciation rights, restricted stock units, performance share units or any combination thereof to certain employees and non-employee directors. Any of the authorized shares may be used for any type of award allowable under the Plan. The Compensation and Benefits Committee (“Committee”) of our Board of Directors has sole authority to (i) establish the awards to be issued, (ii) select the employees and non-employee directors to receive awards, and (iii) approve the terms and conditions of each award contract. Each award under the stock plans is evidenced by an award agreement that specifies the award price, the duration of the award, the number of shares to which the award pertains, and such other provisions as the Committee determines. For stock options, the option price for each grant is at least equal to the fair market value of a share of Cullen/Frost’s common stock on the date of grant. Options granted expire at such time as the Committee determines at the date of grant and in no event does the exercise period exceed a maximum of ten years. As defined in the plans, outstanding unvested awards may immediately vest upon a change-in-control of Cullen/Frost and subsequent termination resulting from the change in control. Director deferred stock units granted to non-employee directors generally have immediate vesting. Upon retirement from our board of directors, non-employee directors will receive one share of our common stock for each director deferred stock unit held. Non-vested restricted stock units granted to employees generally have a three four Performance stock units represent shares potentially issuable in the future. For performance stock units granted in 2024, and years prior to 2021, issuance is based upon the measure of our achievement of relative return on assets over a three-year performance period compared to an identified peer group's achievement of relative return on assets over the same three-year performance period. For performance stock units granted in 2023, 2022, and 2021, issuance is based upon the measure of our achievement of growth in adjusted net revenue, averaged over the three-year performance period, compared to the 2023, 2022, and 2021 base-year amounts, respectively. Performance stock units are eligible to receive equivalent dividend payments based on declared dividends on our common stock during the performance period. Equivalent dividend payments are based upon the ultimate number of shares issued under each performance award and are deferred until such time that the units vest and shares are issued. Options granted to employees generally have a ten four Stock-based Compensation Expense. Valuation of Stock-Based Compensation . For the purposes of recognizing stock-based compensation expense, the fair value of non-vested restricted stock units and director deferred stock units is generally the market price of the stock on the measurement date, which, for us, is the date of the award. The fair value of performance stock units is determined in a similar manner except that the market price of the stock on the measurement date is discounted by the present value of the dividends expected to be paid on our common stock during the service period of the award because dividend equivalent payments on performance stock units are deferred until such time that the units vest and shares are issued. In applying this discount to the market price of our stock on the measurement date, we assumed we would pay a flat quarterly dividend during the service period equal to our most recent dividend payment, which was $0.95, $0.92 and $0.87 in 2024, 2023 and 2022, respectively, discounted at a weighted-average risk-free rate of 4.09%, 5.01% and 4.45% in 2024, 2023 and 2022, respectively.
Advertising Costs	Advertising Costs. Advertising costs are expensed as incurred.
Income Taxes	Income Taxes . Income tax expense is the total of the current year income tax due or refundable and the change in deferred tax assets and liabilities (excluding deferred tax assets and liabilities related to business combinations or components of other comprehensive income). Deferred tax assets and liabilities are the expected future tax amounts for the temporary differences between carrying amounts and tax bases of assets and liabilities, computed using enacted tax rates. A valuation allowance, if needed, reduces deferred tax assets to the expected amount most likely to be realized. Realization of deferred tax assets is dependent upon the generation of a sufficient level of future taxable income. Although realization is not assured, management believes it is more likely than not that all of the deferred tax assets will be realized. Interest and/or penalties related to income taxes are reported as a component of income tax expense. The income tax effects related to settlements of share-based payment awards are reported in earnings as an increase (or decrease) to income tax expense. See Note 12 - Income Taxes. We file a consolidated income tax return with our subsidiaries. Federal income tax expense or benefit has been allocated to subsidiaries on a separate return basis.
Basic and Diluted Earnings Per Common Share	Basic and Diluted Earnings Per Common Share. Earnings per common share is computed using the two-class method prescribed under ASC Topic 260, “Earnings Per Share.” ASC 260 provides that unvested share-based payment awards that contain nonforfeitable rights to dividends or dividend equivalents (whether paid or unpaid) are participating securities and shall be included in the computation of earnings per share pursuant to the two-class method. We have determined that our outstanding non-vested stock units and deferred stock units are participating securities. Under the two-class method, basic earnings per common share is computed by dividing net earnings allocated to common stock by the weighted-average number of common shares outstanding during the applicable period, excluding outstanding participating securities. Diluted earnings per common share is computed using the weighted-average number of shares determined for the basic earnings per common share computation plus the dilutive effect of stock compensation using the treasury stock method. A reconciliation of the weighted-average shares used in calculating basic earnings per common share and the weighted average common shares used in calculating diluted earnings per common share for the reported periods is provided in Note 9 - Earnings Per Common Share. Earnings Per Common Share . Earnings per common share is computed using the two-class method. Basic earnings per common share is computed by dividing net earnings allocated to common stock by the weighted-average number of common shares outstanding during the applicable period, excluding outstanding participating securities. Participating securities include non-vested restricted stock units, deferred stock units and performance stock units (during the performance period), though no actual shares of common stock related to any type of stock unit have been issued. Non-vested restricted stock units and deferred stock units are considered participating securities because holders of these securities receive non-forfeitable dividends at the same rate as holders of our common stock. Holders of performance stock units receive dividend equivalent payments for dividends paid during the performance period at the vesting date of the award based upon the number of units that ultimately vest. Diluted earnings per common share is computed using the weighted-average number of shares determined for the basic earnings per common share computation plus the dilutive effect of stock compensation using the treasury stock method.
Comprehensive Income	Comprehensive Income. Comprehensive income includes all changes in shareholders’ equity during a period, except those resulting from transactions with shareholders. Besides net income, other components of our comprehensive income include the after tax effect of changes in the net unrealized gain/loss on securities available for sale, changes in the net unrealized gain on securities transferred to held to maturity and changes in the net actuarial gain/loss on defined benefit post-retirement benefit plans. See Note 13 - Other Comprehensive Income (Loss).
Derivative Financial Instruments	Derivative Financial Instruments . Our hedging policies permit the use of various derivative financial instruments to manage interest rate risk or to hedge specified assets and liabilities. All derivatives are recorded at fair value on our balance sheet. Derivatives executed with the same counterparty are generally subject to master netting arrangements, however, fair value amounts recognized for derivatives and fair value amounts recognized for the right/obligation to reclaim/return cash collateral are not offset for financial reporting purposes. We may be required to recognize certain contracts and commitments as derivatives when the characteristics of those contracts and commitments meet the definition of a derivative. To qualify for hedge accounting, derivatives must be highly effective at reducing the risk associated with the exposure being hedged and must be designated as a hedge at the inception of the derivative contract. While the assessment of hedge effectiveness is foremost based on the objective of our underlying risk management strategies for a particular hedge, we generally consider a hedge to be highly effective if the change in fair value of the derivative hedging instrument is within 80% to 125% of the opposite change in the fair value of the hedged item attributable to the hedged risk. If derivative instruments are designated as hedges of fair values, and such hedges are highly effective, both the change in the fair value of the hedge and the hedged item are included in current earnings. Fair value adjustments related to highly effective cash flow hedges are recorded in other comprehensive income and are reclassified to earnings when the hedged transaction is reflected in earnings. Actual cash receipts and/or payments and related accruals on derivatives related to hedges are recorded as adjustments to the interest income or interest expense associated with the hedged item. During the life of the hedge, we formally assess whether derivatives designated as hedging instruments continue to be highly effective in offsetting changes in the fair value or cash flows of hedged items. If it is determined that a hedge has ceased to be highly effective, we will discontinue hedge accounting prospectively. At such time, previous adjustments to the carrying value of the hedged item are reversed into current earnings and the derivative instrument is reclassified to a trading position recorded at fair value.
Fair Value Measurements	Fair Value Measurements . In general, fair values of financial instruments are based upon quoted market prices, where available. If such quoted market prices are not available, fair value is based upon internally developed models that primarily use, as inputs, observable market-based parameters. Valuation adjustments may be made to ensure that financial instruments are recorded at fair value. These adjustments may include amounts to reflect counterparty credit quality and our creditworthiness, among other things, as well as unobservable parameters. Any such valuation adjustments are applied consistently over time. See Note 16 - Fair Value Measurements. The fair value of an asset or liability is the price that would be received to sell that asset or paid to transfer that liability in an orderly transaction occurring in the principal market (or most advantageous market in the absence of a principal market) for such asset or liability. In estimating fair value, we utilize valuation techniques that are consistent with the market approach, the income approach and/or the cost approach. Such valuation techniques are consistently applied. Inputs to valuation techniques include the assumptions that market participants would use in pricing an asset or liability. ASC Topic 820 establishes a fair value hierarchy for valuation inputs that gives the highest priority to quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. The fair value hierarchy is as follows: • Level 1 Inputs - Unadjusted quoted prices in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. • Level 2 Inputs - Inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. These might include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (such as interest rates, volatilities, prepayment speeds, credit risks, etc.) or inputs that are derived principally from or corroborated by market data by correlation or other means. • Level 3 Inputs - Unobservable inputs for determining the fair values of assets or liabilities that reflect an entity’s own assumptions about the assumptions that market participants would use in pricing the assets or liabilities. In general, fair value is based upon quoted market prices, where available. If such quoted market prices are not available, fair value is based upon internally developed models that primarily use, as inputs, observable market- based parameters. Valuation adjustments may be made to ensure that financial instruments are recorded at fair value. These adjustments may include amounts to reflect counterparty credit quality and our creditworthiness, among other things, as well as unobservable parameters. Any such valuation adjustments are applied consistently over time. Our valuation methodologies may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. While management believes our valuation methodologies are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different estimate of fair value at the reporting date. Furthermore, the reported fair value amounts have not been comprehensively revalued since the presentation dates, and therefore, estimates of fair value after the balance sheet date may differ significantly from the amounts presented herein. A more detailed description of the valuation methodologies used for assets and liabilities measured at fair value is set forth below. Transfers between levels of the fair value hierarchy are recognized on the actual date of the event or circumstances that caused the transfer, which generally coincides with our monthly and/or quarterly valuation process. Financial Assets and Financial Liabilities: Financial assets and financial liabilities measured at fair value on a recurring basis include the following: Securities Available for Sale . U.S. Treasury securities are reported at fair value utilizing Level 1 inputs. Other securities classified as available for sale are reported at fair value utilizing Level 2 inputs. For these securities, 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. We review the prices supplied by the independent pricing service, as well as their underlying pricing methodologies, for reasonableness and to ensure such prices are aligned with traditional pricing matrices. In general, we do not purchase investment portfolio securities that are esoteric or that have a complicated structure. Our entire portfolio consists of traditional investments, nearly all of which are U.S. Treasury obligations, federal agency bullet or mortgage pass-through securities, or general obligation or revenue based municipal bonds. Pricing for such instruments is fairly generic and is easily obtained. From time to time, we will validate prices supplied by the independent pricing service by comparison to prices obtained from third-party sources or derived using internal models. Trading Securities . U.S. Treasury securities and exchange-listed common stock are reported at fair value utilizing Level 1 inputs. Other securities classified as trading are reported at fair value utilizing Level 2 inputs in the same manner as described above for securities available for sale. Derivatives . Derivatives are generally reported at fair value utilizing Level 2 inputs. We utilize internal valuation methods with observable market data inputs to estimate the fair values of our outstanding interest rate, commodity and foreign currency derivative contracts. We also obtain dealer quotations and/or utilize third-party models for comparative purposes to assess the reasonableness of our model valuations. Though there has never been a significant discrepancy in the valuations, should such a significant discrepancy arise, we would obtain price verification from a third-party dealer. In cases where significant credit valuation adjustments are incorporated into the estimation of fair value, reported amounts are considered to have been derived utilizing Level 3 inputs. For purposes of potential valuation adjustments to our derivative positions, we evaluate the credit risk of our counterparties as well as ours. Accordingly, we have considered factors such as the likelihood of our default and the default of our counterparties, our net exposures and remaining contractual life, among other things, in determining if any fair value adjustments related to credit risk are required. Counterparty exposure is evaluated by netting positions that are subject to master netting arrangements, as well as considering the amount of collateral securing the position. We review our counterparty exposure on a regular basis, and, when necessary, appropriate business actions are taken to adjust the exposure. We also utilize this approach to estimate our own credit risk on derivative liability positions. To date, we have not realized any significant losses due to a counterparty’s inability to pay any net uncollateralized position. The change in value of derivative assets and derivative liabilities attributable to credit risk was not significant during the reported periods. Certain financial assets and financial liabilities are measured at fair value on a nonrecurring basis; that is, the instruments are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (for example, when there is evidence of impairment). Financial assets measured at fair value on a non-recurring basis during the reported periods include certain loans reported at the fair value of the underlying collateral if repayment is expected solely from the collateral. Collateral values are estimated using Level 2 inputs based on observable market data, typically in the case of real estate collateral, or Level 3 inputs based on customized discounting criteria, typically in the case of non-real estate collateral such as inventory, oil and gas reserves, accounts receivable, equipment or other business assets. Non-Financial Assets and Non-Financial Liabilities: We do not have any non-financial assets or non-financial liabilities measured at fair value on a recurring basis. From time to time, non-financial assets measured at fair value on a non-recurring basis may include certain foreclosed assets which, upon initial recognition, were remeasured and reported at fair value through a charge-off to the allowance for loan losses and certain foreclosed assets which, subsequent to their initial recognition, were remeasured at fair value through a write-down included in other non-interest expense. The fair value of a foreclosed asset is estimated using Level 2 inputs based on observable market data or Level 3 inputs based on customized discounting criteria. During the reported periods, all fair value measurements for foreclosed assets utilized Level 2 inputs. The following table presents foreclosed assets that were remeasured and reported at fair value: 2024 2023 2022 Foreclosed assets remeasured at initial recognition: Carrying value of foreclosed assets prior to remeasurement $ 19,297 $ — $ 239 Charge-offs recognized in the allowance for credit losses on loans (3,797) — — Fair value $ 15,500 $ — $ 239 Charge-offs recognized upon loan foreclosures are generally offset by general or specific allocations of the allowance for credit losses on loans and generally do not, and did not during the reported periods, significantly impact our credit loss expense. Regulatory guidelines require us to reevaluate the fair value of other real estate owned on at least an annual basis. While our policy is to comply with the regulatory guidelines, our general practice is to reevaluate the fair value of collateral supporting collateral dependent loans on a quarterly basis. Thus, appraisals are generally not considered to be outdated, and we typically do not make any adjustments to the appraised values. ASC Topic 825, “Financial Instruments,” requires disclosure of the fair value of financial assets and financial liabilities, including those financial assets and financial liabilities that are not measured and reported at fair value on a recurring basis or non-recurring basis. The estimated fair value approximates carrying value for cash and cash equivalents, accrued interest and the cash surrender value of life insurance policies. The methodologies for other financial assets and financial liabilities that are not measured and reported at fair value on a recurring basis or non-recurring basis are discussed below: Loans . The estimated fair value approximates carrying value for variable-rate loans that reprice frequently and with no significant change in credit risk. The fair value of fixed-rate loans and variable-rate loans which reprice on an infrequent basis is estimated by discounting future cash flows using the current interest rates at which similar loans with similar terms would be made to borrowers of similar credit quality. An overall valuation adjustment is made for specific credit risks as well as general portfolio credit risk. Deposits . The estimated fair value approximates carrying value for demand deposits. The fair value of fixed-rate deposit liabilities with defined maturities is estimated by discounting future cash flows using the interest rates currently offered for deposits of similar remaining maturities. The estimated fair value of deposits does not take into account the value of our long-term relationships with depositors, commonly known as core deposit intangibles, which are separate intangible assets, and not considered financial instruments. Nonetheless, we would likely realize a core deposit premium if our deposit portfolio were sold in the principal market for such deposits. Borrowed Funds . The estimated fair value approximates carrying value for short-term borrowings. The fair value of long-term fixed-rate borrowings is estimated using quoted market prices, if available, or by discounting future cash flows using current interest rates for similar financial instruments. The estimated fair value approximates carrying value for variable-rate junior subordinated deferrable interest debentures that reprice quarterly. Loan Commitments, Standby and Commercial Letters of Credit . Our lending commitments have variable interest rates and “escape” clauses if the customer’s credit quality deteriorates. Therefore, the fair values of these items are not significant and are not included in the following table.
Transfers of Financial Assets	Transfers of Financial Assets . Transfers of financial assets are accounted for as sales when control over the assets has been surrendered. Control over transferred assets is deemed to be surrendered when (i) the assets have been isolated from us, (ii) the transferee obtains the right (free of conditions that constrain it from taking advantage of that right) to pledge or exchange the transferred assets, and (iii) we do not maintain effective control over the transferred assets through an agreement to repurchase them before their maturity.
Loss Contingencies	Loss Contingencies . Loss contingencies, including claims and legal actions arising in the ordinary course of business are recorded as liabilities when the likelihood of loss is probable and an amount or range of loss can be reasonably estimated.
Trust Assets	Trust Assets. Assets of our trust department, other than cash on deposit at Frost Bank, are not included in the accompanying financial statements because they are not our assets.
Accounting Changes, Reclassifications and Restatement	Accounting Changes, Reclassifications and Restatements.
Reclassification, Comparability Adjustment	Certain items in prior financial statements have been reclassified to conform to the current presentation.
Financing Receivable, Excluding Accrued Interest, Allowance For Credit Losses Policy For Uncollectible Amounts	Allowance for Credit Losses - Loans. The allowance for credit losses on loans is a contra-asset valuation account, calculated in accordance with ASC 326, that is deducted from the amortized cost basis of loans to present management's best estimate of the net amount expected to be collected. Loans are charged-off against the allowance when deemed uncollectible by management. Expected recoveries do not exceed the aggregate of amounts previously charged-off and expected to be charged-off. Adjustments to the allowance are reported in our income statement as a component of credit loss expense. Management has made the accounting policy election to exclude accrued interest receivable on loans from the estimate of credit losses. Further information regarding our policies and methodology used to estimate the allowance for credit losses on loans is presented in Note 3 - Loans. Allowance For Credit Losses - Loans. The allowance for credit losses on loans is a contra-asset valuation account, calculated in accordance with ASC 326, that is deducted from the amortized cost basis of loans to present the net amount expected to be collected. The amount of the allowance represents management's best estimate of current expected credit losses on loans considering available information, from internal and external sources, relevant to assessing collectibility over the loans' contractual terms, adjusted for expected prepayments when appropriate. The contractual term excludes expected extensions, renewals and modifications unless (i) management has a reasonable expectation that a loan to an individual borrower that is experiencing financial difficulty will be modified or (ii) such extension or renewal options are not unconditionally cancellable by us and, in such cases, the borrower is likely to meet applicable conditions and likely to request extension or renewal. Relevant available information includes historical credit loss experience; current conditions; and reasonable and supportable forecasts. While historical credit loss experience provides the basis for the estimation of expected credit losses, adjustments to historical loss information may be made for differences in current portfolio-specific risk characteristics, environmental conditions, or other relevant factors. The allowance for credit losses is measured on a collective basis for portfolios of loans when similar risk characteristics exist. Loans that do not share risk characteristics are evaluated for expected credit losses on an individual basis and excluded from the collective evaluation. Expected credit losses for collateral dependent loans, including loans where the borrower is experiencing financial difficulty but foreclosure is not probable, are based on the fair value of the collateral at the reporting date, adjusted for selling costs as appropriate. Credit loss expense related to loans reflects the totality of actions taken on all loans for a particular period including any necessary increases or decreases in the allowance related to changes in credit loss expectations associated with specific loans or pools of loans. Portions of the allowance may be allocated for specific credits; however, the entire allowance is available for any credit that, in management’s judgment, should be charged off. While management utilizes its best judgment and information available, the ultimate appropriateness of the allowance is dependent upon a variety of factors beyond our control, including the performance of our loan portfolio, the economy, changes in interest rates and the view of the regulatory authorities toward loan classifications. In calculating the allowance for credit losses, most loans are segmented into pools based upon similar characteristics and risk profiles. Common characteristics and risk profiles include the type/purpose of loan, underlying collateral, geographical similarity, and historical/expected credit loss patterns. In developing these loan pools for the purposes of modeling expected credit losses, we also analyzed the degree of correlation in how loans within each portfolio respond when subjected to varying economic conditions and scenarios as well as other portfolio stress factors. For modeling purposes, our loan pools include (i) commercial and industrial non-revolving, (ii) commercial and industrial revolving, (iii) energy, (iv) commercial real estate - owner occupied, (v) commercial real estate - non-owner occupied, (vi) commercial real estate - construction/land development, (vii) consumer real estate and (viii) consumer and other. Prior to 2023, energy loans were included within the commercial and industrial loan pools. See discussion of the 2023 model updates below. We periodically reassess each pool to ensure the loans within the pool continue to share similar characteristics and risk profiles and to determine whether further segmentation is necessary. For each loan pool, we measure expected credit losses over the life of each loan utilizing a combination of models which measure (i) probability of default (“PD”), which is the likelihood that loan will stop performing/default, (ii) probability of attrition (“PA”), which is the likelihood that a loan will pay-off prior to maturity, (iii) loss given default (“LGD”), which is the expected loss rate for loans in default and (iv) exposure at default (“EAD”), which is the estimated outstanding principal balance of the loans upon default, including the expected funding of unfunded commitments outstanding as of the measurement date. For commercial loan portfolios, the PD is calculated using a transition matrix to determine the likelihood of a customer’s risk grade migrating from one specified range of risk grades to a different specified range. Expected credit losses are calculated as the product of PD (adjusted for attrition), LGD and EAD. This methodology builds on default probabilities already incorporated into our risk grading process by utilizing pool-specific historical loss rates to calculate expected credit losses. These pool-specific historical loss rates may be adjusted for current macroeconomic assumptions, as further discussed below, and other factors such as differences in underwriting standards, portfolio mix, or when historical asset terms do not reflect the contractual terms of the financial assets being evaluated as of the measurement date. Each time we measure expected credit losses, we assess the relevancy of historical loss information and consider any necessary adjustments to address any differences in asset-specific characteristics. Due to their short-term nature, expected credit losses for overdrafts included in consumer and other loans are based solely upon a weighting of recent historical charge-offs over a period of three years. The measurement of expected credit losses is impacted by loan/borrower attributes and certain macroeconomic variables. Significant loan/borrower attributes utilized in our modeling processes include, among other things, (i) origination date, (ii) maturity date, (iii) payment type, (iv) collateral type and amount, (v) current risk grade, (vi) current unpaid balance and commitment utilization rate, (vii) payment status/delinquency history and (viii) expected recoveries of previously charged-off amounts. Significant macroeconomic variables utilized in our modeling processes include, among other things, (i) Gross State Product for Texas and U.S. Gross Domestic Product, (ii) selected market interest rates including U.S. Treasury rates, bank prime rate, 30-year fixed mortgage rate, BBB corporate bond rate, among others, (iii) unemployment rates, (iv) commercial and residential property prices in Texas and the U.S. as a whole, (v) West Texas Intermediate crude oil price and (vi) total stock market index. PD and PA were estimated by analyzing internally-sourced data related to historical performance of each loan pool over a complete economic cycle. PD and PA are adjusted to reflect the current impact of certain macroeconomic variables as well as their expected changes over a reasonable and supportable forecast period. We have determined that we are reasonably able to forecast the macroeconomic variables used in our modeling processes with an acceptable degree of confidence for a total of two years with the last twelve months of the forecast period encompassing a reversion process whereby the forecasted macroeconomic variables are reverted to their historical mean utilizing a rational, systematic basis. The macroeconomic variables utilized as inputs in our modeling processes were subjected to a variety of analysis procedures and were selected primarily based on statistical relevancy and correlation to our historical credit losses. By reverting these modeling inputs to their historical mean and considering loan/borrower specific attributes, our models are intended to yield a measurement of expected credit losses that reflects our average historical loss rates for periods subsequent to the twelve-month reversion period. The LGD is based on historical recovery averages for each loan pool, adjusted to reflect the current impact of certain macroeconomic variables as well as their expected changes over a two-year forecast period, with the final twelve months of the forecast period encompassing a reversion process, which management considers to be both reasonable and supportable. This same forecast/reversion period is used for all macroeconomic variables used in all of our models. EAD is estimated using a linear regression model that estimates the average percentage of the loan balance that remains at the time of a default event. Management qualitatively adjusts model results for risk factors that are not considered within our modeling processes but are nonetheless relevant in assessing the expected credit losses within our loan pools. These qualitative factor (“Q-Factor”) and other qualitative adjustments may increase or decrease management's estimate of expected credit losses by a calculated percentage or amount based upon the estimated level of risk. The various risks that may be considered in making Q-Factor and other qualitative adjustments include, among other things, the impact of (i) changes in lending policies and procedures, including changes in underwriting standards and practices for collections, write-offs, and recoveries, (ii) actual and expected changes in international, national, regional, and local economic and business conditions and developments that affect the collectibility of the loan pools, (iii) changes in the nature and volume of the loan pools and in the terms of the underlying loans, (iv) changes in the experience, ability, and depth of our lending management and staff, (v) changes in volume and severity of past due financial assets, the volume of non-accrual assets, and the volume and severity of adversely classified or graded assets, (vi) changes in the quality of our credit review function, (vii) changes in the value of the underlying collateral for loans that are non-collateral dependent, (viii) the existence, growth, and effect of any concentrations of credit and (ix) other factors such as the regulatory, legal and technological environments; competition; and events such as natural disasters or health pandemics. In some cases, management may determine that an individual loan exhibits unique risk characteristics which differentiate the loan from other loans within our loan pools. In such cases, the loans are evaluated for expected credit losses on an individual basis and excluded from the collective evaluation. Specific allocations of the allowance for credit losses are determined by analyzing the borrower’s ability to repay amounts owed, collateral deficiencies, the relative risk grade of the loan and economic conditions affecting the borrower’s industry, among other things. A loan is considered to be collateral dependent when, based upon management's assessment, the borrower is experiencing financial difficulty and repayment is expected to be provided substantially through the operation or sale of the collateral. In such cases, expected credit losses are based on the fair value of the collateral at the measurement date, adjusted for estimated selling costs if satisfaction of the loan depends on the sale of the collateral. We reevaluate the fair value of collateral supporting collateral dependent loans on a quarterly basis. The fair value of real estate collateral supporting collateral dependent loans is evaluated by our internal appraisal services using a methodology that is consistent with the Uniform Standards of Professional Appraisal Practice. The fair value of collateral supporting collateral dependent construction loans is based on an “as is” valuation. During the first quarter of 2024, we updated our non-owner-occupied commercial real estate loan models as well as our consumer and other loan models. Our prior non-owner-occupied commercial real estate loan models were legacy models developed for stress-testing purposes by a third-party using external market data. The updated non-owner-occupied commercial real estate loan models are now based on internal historical loan data and risk grade information and the modeling processes are now consistent with those used with our other commercial loan models. Our prior consumer and other loan models relied upon certain components that did not use loan level attributes and were less sensitive to macroeconomic variables. The updated consumer and other loan models are now based on internal historical loan data and utilize more loan-level attributes and the modeling processes are now consistent with those used with our consumer real estate loan models. The overall approximate impact of the model updates during the first quarter was a $7.2 million increase ($6.2 million related to non-owner-occupied commercial real estate loans and $923 thousand related to consumer and other loans) in modeled expected credit losses on loans; however, the impact of this increase was largely offset by reductions in qualitative adjustments as some of the risks to which those qualitative adjustments related are now considered and incorporated in the updated models. During the first quarter of 2023, we recalibrated and updated all of our commercial loan models, with the exception of the models related to commercial real estate - non-owner-occupied loans, as well as our consumer real estate loan models. While the fundamental modeling methodologies remain unchanged, the updates included (i) separating the energy loan pool from the commercial and industrial pool as a result of differences in loss characteristics observed in recent history and (ii) changing the modeling approach related to loan renewals whereby each renewal is treated as a separate loan which impacted loan life assumptions. The overall approximate impact of the model updates during the first quarter was a $45.0 million decrease in modeled expected credit losses on loans though the impact of this decrease was largely offset with discretionary qualitative adjustments. The decrease in modeled expected credit losses on loans was largely driven by lower measurements for PD and LGD based on the historical data series (2008 through 2018) used for the recalibration. This period was one of relatively low losses and included higher levels of government stimulus. The lower PD and LGD measurements were also impacted by shorter loan life assumptions due to the aforementioned change in the modeling approach related to loan renewals. Generally, a commercial loan, or a portion thereof, is charged-off immediately when it is determined, through the analysis of any available current financial information with regards to the borrower, that the borrower is incapable of servicing unsecured debt, there is little or no prospect for near term improvement and no realistic strengthening action of significance is pending or, in the case of secured debt, when it is determined, through analysis of current information with regards to our collateral position, that amounts due from the borrower are in excess of the calculated current fair value of the collateral. Notwithstanding the foregoing, generally, commercial loans that become past due 180 cumulative days are charged-off. Generally, a consumer loan, or a portion thereof, is charged-off in accordance with regulatory guidelines which provide that such loans be charged-off when we become aware of the loss, such as from a triggering event that may include new information about a borrower’s intent/ability to repay the loan, bankruptcy, fraud or death, among other things, but in any event the charge-off must be taken within specified delinquency time frames. Such delinquency time frames state that closed-end retail loans (loans with pre-defined maturity dates, such as real estate mortgages, home equity loans and consumer installment loans) that become past due 120 cumulative days and open-end retail loans (loans that roll-over at the end of each term, such as home equity lines of credit) that become past due 180 cumulative days should be classified as a loss and charged-off.

Receivables, Loans, Notes Recei

Receivables, Loans, Notes Receivable, and Others (Policies)	12 Months Ended
	Dec. 31, 2024
Receivables [Abstract]
Financing Receivable, Excluding Accrued Interest, Allowance For Credit Losses Policy For Uncollectible Amounts	Allowance for Credit Losses - Loans. The allowance for credit losses on loans is a contra-asset valuation account, calculated in accordance with ASC 326, that is deducted from the amortized cost basis of loans to present management's best estimate of the net amount expected to be collected. Loans are charged-off against the allowance when deemed uncollectible by management. Expected recoveries do not exceed the aggregate of amounts previously charged-off and expected to be charged-off. Adjustments to the allowance are reported in our income statement as a component of credit loss expense. Management has made the accounting policy election to exclude accrued interest receivable on loans from the estimate of credit losses. Further information regarding our policies and methodology used to estimate the allowance for credit losses on loans is presented in Note 3 - Loans. Allowance For Credit Losses - Loans. The allowance for credit losses on loans is a contra-asset valuation account, calculated in accordance with ASC 326, that is deducted from the amortized cost basis of loans to present the net amount expected to be collected. The amount of the allowance represents management's best estimate of current expected credit losses on loans considering available information, from internal and external sources, relevant to assessing collectibility over the loans' contractual terms, adjusted for expected prepayments when appropriate. The contractual term excludes expected extensions, renewals and modifications unless (i) management has a reasonable expectation that a loan to an individual borrower that is experiencing financial difficulty will be modified or (ii) such extension or renewal options are not unconditionally cancellable by us and, in such cases, the borrower is likely to meet applicable conditions and likely to request extension or renewal. Relevant available information includes historical credit loss experience; current conditions; and reasonable and supportable forecasts. While historical credit loss experience provides the basis for the estimation of expected credit losses, adjustments to historical loss information may be made for differences in current portfolio-specific risk characteristics, environmental conditions, or other relevant factors. The allowance for credit losses is measured on a collective basis for portfolios of loans when similar risk characteristics exist. Loans that do not share risk characteristics are evaluated for expected credit losses on an individual basis and excluded from the collective evaluation. Expected credit losses for collateral dependent loans, including loans where the borrower is experiencing financial difficulty but foreclosure is not probable, are based on the fair value of the collateral at the reporting date, adjusted for selling costs as appropriate. Credit loss expense related to loans reflects the totality of actions taken on all loans for a particular period including any necessary increases or decreases in the allowance related to changes in credit loss expectations associated with specific loans or pools of loans. Portions of the allowance may be allocated for specific credits; however, the entire allowance is available for any credit that, in management’s judgment, should be charged off. While management utilizes its best judgment and information available, the ultimate appropriateness of the allowance is dependent upon a variety of factors beyond our control, including the performance of our loan portfolio, the economy, changes in interest rates and the view of the regulatory authorities toward loan classifications. In calculating the allowance for credit losses, most loans are segmented into pools based upon similar characteristics and risk profiles. Common characteristics and risk profiles include the type/purpose of loan, underlying collateral, geographical similarity, and historical/expected credit loss patterns. In developing these loan pools for the purposes of modeling expected credit losses, we also analyzed the degree of correlation in how loans within each portfolio respond when subjected to varying economic conditions and scenarios as well as other portfolio stress factors. For modeling purposes, our loan pools include (i) commercial and industrial non-revolving, (ii) commercial and industrial revolving, (iii) energy, (iv) commercial real estate - owner occupied, (v) commercial real estate - non-owner occupied, (vi) commercial real estate - construction/land development, (vii) consumer real estate and (viii) consumer and other. Prior to 2023, energy loans were included within the commercial and industrial loan pools. See discussion of the 2023 model updates below. We periodically reassess each pool to ensure the loans within the pool continue to share similar characteristics and risk profiles and to determine whether further segmentation is necessary. For each loan pool, we measure expected credit losses over the life of each loan utilizing a combination of models which measure (i) probability of default (“PD”), which is the likelihood that loan will stop performing/default, (ii) probability of attrition (“PA”), which is the likelihood that a loan will pay-off prior to maturity, (iii) loss given default (“LGD”), which is the expected loss rate for loans in default and (iv) exposure at default (“EAD”), which is the estimated outstanding principal balance of the loans upon default, including the expected funding of unfunded commitments outstanding as of the measurement date. For commercial loan portfolios, the PD is calculated using a transition matrix to determine the likelihood of a customer’s risk grade migrating from one specified range of risk grades to a different specified range. Expected credit losses are calculated as the product of PD (adjusted for attrition), LGD and EAD. This methodology builds on default probabilities already incorporated into our risk grading process by utilizing pool-specific historical loss rates to calculate expected credit losses. These pool-specific historical loss rates may be adjusted for current macroeconomic assumptions, as further discussed below, and other factors such as differences in underwriting standards, portfolio mix, or when historical asset terms do not reflect the contractual terms of the financial assets being evaluated as of the measurement date. Each time we measure expected credit losses, we assess the relevancy of historical loss information and consider any necessary adjustments to address any differences in asset-specific characteristics. Due to their short-term nature, expected credit losses for overdrafts included in consumer and other loans are based solely upon a weighting of recent historical charge-offs over a period of three years. The measurement of expected credit losses is impacted by loan/borrower attributes and certain macroeconomic variables. Significant loan/borrower attributes utilized in our modeling processes include, among other things, (i) origination date, (ii) maturity date, (iii) payment type, (iv) collateral type and amount, (v) current risk grade, (vi) current unpaid balance and commitment utilization rate, (vii) payment status/delinquency history and (viii) expected recoveries of previously charged-off amounts. Significant macroeconomic variables utilized in our modeling processes include, among other things, (i) Gross State Product for Texas and U.S. Gross Domestic Product, (ii) selected market interest rates including U.S. Treasury rates, bank prime rate, 30-year fixed mortgage rate, BBB corporate bond rate, among others, (iii) unemployment rates, (iv) commercial and residential property prices in Texas and the U.S. as a whole, (v) West Texas Intermediate crude oil price and (vi) total stock market index. PD and PA were estimated by analyzing internally-sourced data related to historical performance of each loan pool over a complete economic cycle. PD and PA are adjusted to reflect the current impact of certain macroeconomic variables as well as their expected changes over a reasonable and supportable forecast period. We have determined that we are reasonably able to forecast the macroeconomic variables used in our modeling processes with an acceptable degree of confidence for a total of two years with the last twelve months of the forecast period encompassing a reversion process whereby the forecasted macroeconomic variables are reverted to their historical mean utilizing a rational, systematic basis. The macroeconomic variables utilized as inputs in our modeling processes were subjected to a variety of analysis procedures and were selected primarily based on statistical relevancy and correlation to our historical credit losses. By reverting these modeling inputs to their historical mean and considering loan/borrower specific attributes, our models are intended to yield a measurement of expected credit losses that reflects our average historical loss rates for periods subsequent to the twelve-month reversion period. The LGD is based on historical recovery averages for each loan pool, adjusted to reflect the current impact of certain macroeconomic variables as well as their expected changes over a two-year forecast period, with the final twelve months of the forecast period encompassing a reversion process, which management considers to be both reasonable and supportable. This same forecast/reversion period is used for all macroeconomic variables used in all of our models. EAD is estimated using a linear regression model that estimates the average percentage of the loan balance that remains at the time of a default event. Management qualitatively adjusts model results for risk factors that are not considered within our modeling processes but are nonetheless relevant in assessing the expected credit losses within our loan pools. These qualitative factor (“Q-Factor”) and other qualitative adjustments may increase or decrease management's estimate of expected credit losses by a calculated percentage or amount based upon the estimated level of risk. The various risks that may be considered in making Q-Factor and other qualitative adjustments include, among other things, the impact of (i) changes in lending policies and procedures, including changes in underwriting standards and practices for collections, write-offs, and recoveries, (ii) actual and expected changes in international, national, regional, and local economic and business conditions and developments that affect the collectibility of the loan pools, (iii) changes in the nature and volume of the loan pools and in the terms of the underlying loans, (iv) changes in the experience, ability, and depth of our lending management and staff, (v) changes in volume and severity of past due financial assets, the volume of non-accrual assets, and the volume and severity of adversely classified or graded assets, (vi) changes in the quality of our credit review function, (vii) changes in the value of the underlying collateral for loans that are non-collateral dependent, (viii) the existence, growth, and effect of any concentrations of credit and (ix) other factors such as the regulatory, legal and technological environments; competition; and events such as natural disasters or health pandemics. In some cases, management may determine that an individual loan exhibits unique risk characteristics which differentiate the loan from other loans within our loan pools. In such cases, the loans are evaluated for expected credit losses on an individual basis and excluded from the collective evaluation. Specific allocations of the allowance for credit losses are determined by analyzing the borrower’s ability to repay amounts owed, collateral deficiencies, the relative risk grade of the loan and economic conditions affecting the borrower’s industry, among other things. A loan is considered to be collateral dependent when, based upon management's assessment, the borrower is experiencing financial difficulty and repayment is expected to be provided substantially through the operation or sale of the collateral. In such cases, expected credit losses are based on the fair value of the collateral at the measurement date, adjusted for estimated selling costs if satisfaction of the loan depends on the sale of the collateral. We reevaluate the fair value of collateral supporting collateral dependent loans on a quarterly basis. The fair value of real estate collateral supporting collateral dependent loans is evaluated by our internal appraisal services using a methodology that is consistent with the Uniform Standards of Professional Appraisal Practice. The fair value of collateral supporting collateral dependent construction loans is based on an “as is” valuation. During the first quarter of 2024, we updated our non-owner-occupied commercial real estate loan models as well as our consumer and other loan models. Our prior non-owner-occupied commercial real estate loan models were legacy models developed for stress-testing purposes by a third-party using external market data. The updated non-owner-occupied commercial real estate loan models are now based on internal historical loan data and risk grade information and the modeling processes are now consistent with those used with our other commercial loan models. Our prior consumer and other loan models relied upon certain components that did not use loan level attributes and were less sensitive to macroeconomic variables. The updated consumer and other loan models are now based on internal historical loan data and utilize more loan-level attributes and the modeling processes are now consistent with those used with our consumer real estate loan models. The overall approximate impact of the model updates during the first quarter was a $7.2 million increase ($6.2 million related to non-owner-occupied commercial real estate loans and $923 thousand related to consumer and other loans) in modeled expected credit losses on loans; however, the impact of this increase was largely offset by reductions in qualitative adjustments as some of the risks to which those qualitative adjustments related are now considered and incorporated in the updated models. During the first quarter of 2023, we recalibrated and updated all of our commercial loan models, with the exception of the models related to commercial real estate - non-owner-occupied loans, as well as our consumer real estate loan models. While the fundamental modeling methodologies remain unchanged, the updates included (i) separating the energy loan pool from the commercial and industrial pool as a result of differences in loss characteristics observed in recent history and (ii) changing the modeling approach related to loan renewals whereby each renewal is treated as a separate loan which impacted loan life assumptions. The overall approximate impact of the model updates during the first quarter was a $45.0 million decrease in modeled expected credit losses on loans though the impact of this decrease was largely offset with discretionary qualitative adjustments. The decrease in modeled expected credit losses on loans was largely driven by lower measurements for PD and LGD based on the historical data series (2008 through 2018) used for the recalibration. This period was one of relatively low losses and included higher levels of government stimulus. The lower PD and LGD measurements were also impacted by shorter loan life assumptions due to the aforementioned change in the modeling approach related to loan renewals. Generally, a commercial loan, or a portion thereof, is charged-off immediately when it is determined, through the analysis of any available current financial information with regards to the borrower, that the borrower is incapable of servicing unsecured debt, there is little or no prospect for near term improvement and no realistic strengthening action of significance is pending or, in the case of secured debt, when it is determined, through analysis of current information with regards to our collateral position, that amounts due from the borrower are in excess of the calculated current fair value of the collateral. Notwithstanding the foregoing, generally, commercial loans that become past due 180 cumulative days are charged-off. Generally, a consumer loan, or a portion thereof, is charged-off in accordance with regulatory guidelines which provide that such loans be charged-off when we become aware of the loss, such as from a triggering event that may include new information about a borrower’s intent/ability to repay the loan, bankruptcy, fraud or death, among other things, but in any event the charge-off must be taken within specified delinquency time frames. Such delinquency time frames state that closed-end retail loans (loans with pre-defined maturity dates, such as real estate mortgages, home equity loans and consumer installment loans) that become past due 120 cumulative days and open-end retail loans (loans that roll-over at the end of each term, such as home equity lines of credit) that become past due 180 cumulative days should be classified as a loss and charged-off.

Fair Value Measures and Disclos

Fair Value Measures and Disclosures (Policies)	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Off-Balance-Sheet Credit Exposure	Allowance For Credit Losses - Off-Balance-Sheet Credit Exposures. The allowance for credit losses on off-balance-sheet credit exposures is a liability account, calculated in accordance with ASC 326, representing expected credit losses over the contractual period for which we are exposed to credit risk resulting from a contractual obligation to extend credit. No allowance is recognized if we have the unconditional right to cancel the obligation. The allowance is reported as a component of accrued interest payable and other liabilities in our consolidated balance sheets. Adjustments to the allowance are reported in our income statement as a component of credit loss expense. Further information regarding our policies and methodology used to estimate the allowance for credit losses on off-balance-sheet credit exposures is presented in Note 7 - Off-Balance-Sheet Arrangements, Commitments, Guarantees and Contingencies. Allowance For Credit Losses - Off-Balance-Sheet Credit Exposures. The allowance for credit losses on off-balance-sheet credit exposures is a liability account, calculated in accordance with ASC 326, representing expected credit losses over the contractual period for which we are exposed to credit risk resulting from a contractual obligation to extend credit. No allowance is recognized if we have the unconditional right to cancel the obligation. Off-balance-sheet credit exposures primarily consist of amounts available under outstanding lines of credit and letters of credit detailed in the table above. For the period of exposure, the estimate of expected credit losses considers both the likelihood that funding will occur and the amount expected to be funded over the estimated remaining life of the commitment or other off-balance-sheet exposure. The likelihood and expected amount of funding are based on historical utilization rates. The amount of the allowance represents management's best estimate of expected credit losses on commitments expected to be funded over the contractual life of the commitment. Estimating credit losses on amounts expected to be funded uses the same methodology as described for loans in Note 3 - Loans as if such commitments were funded. This methodology was also impacted by the model updates during 2024 and 2023, as described in Note 3 - Loans. For 2024, the overall approximate impact of the model updates was a $1.8 million increase in modeled expected credit losses for off-balance-sheet credit exposures ($1.6 million related to consumer and other loan commitments and $211 thousand related to non-owner-occupied commercial real estate loan commitments). For 2023, the overall approximate impact of the model updates was a $19.0 million decrease in modeled expected credit losses for off-balance-sheet credit exposures, though the impact of this decrease was largely offset with discretionary qualitative adjustments.

Earnings Per Share (Policies)

Earnings Per Share (Policies)	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Basic and Diluted Earnings Per Common Share	Basic and Diluted Earnings Per Common Share. Earnings per common share is computed using the two-class method prescribed under ASC Topic 260, “Earnings Per Share.” ASC 260 provides that unvested share-based payment awards that contain nonforfeitable rights to dividends or dividend equivalents (whether paid or unpaid) are participating securities and shall be included in the computation of earnings per share pursuant to the two-class method. We have determined that our outstanding non-vested stock units and deferred stock units are participating securities. Under the two-class method, basic earnings per common share is computed by dividing net earnings allocated to common stock by the weighted-average number of common shares outstanding during the applicable period, excluding outstanding participating securities. Diluted earnings per common share is computed using the weighted-average number of shares determined for the basic earnings per common share computation plus the dilutive effect of stock compensation using the treasury stock method. A reconciliation of the weighted-average shares used in calculating basic earnings per common share and the weighted average common shares used in calculating diluted earnings per common share for the reported periods is provided in Note 9 - Earnings Per Common Share. Earnings Per Common Share . Earnings per common share is computed using the two-class method. Basic earnings per common share is computed by dividing net earnings allocated to common stock by the weighted-average number of common shares outstanding during the applicable period, excluding outstanding participating securities. Participating securities include non-vested restricted stock units, deferred stock units and performance stock units (during the performance period), though no actual shares of common stock related to any type of stock unit have been issued. Non-vested restricted stock units and deferred stock units are considered participating securities because holders of these securities receive non-forfeitable dividends at the same rate as holders of our common stock. Holders of performance stock units receive dividend equivalent payments for dividends paid during the performance period at the vesting date of the award based upon the number of units that ultimately vest. Diluted earnings per common share is computed using the weighted-average number of shares determined for the basic earnings per common share computation plus the dilutive effect of stock compensation using the treasury stock method.

Compensation Related Costs, Pos

Compensation Related Costs, Postemployment Benefits (Policies)	12 Months Ended
	Dec. 31, 2024
Postemployment Benefits [Abstract]
Stock Based Compensation	Share-Based Payments . Compensation expense for stock options, non-vested stock awards/stock units and deferred stock units is based on the fair value of the award on the measurement date, which, for us, is the date of the grant and is recognized ratably over the service period of the award. Compensation expense for performance stock units is based on the fair value of the award on the measurement date, which, for us, is the date of the grant and is recognized over the service period of the award based upon the probable number of units expected to vest. The fair value of stock options is estimated using a binomial lattice-based valuation model. The fair value of non-vested stock awards/stock units and deferred stock units is generally the market price of our stock on the date of grant. The fair value of performance stock units is generally the market price of our stock on the date of grant discounted by the present value of the dividends expected to be paid on our common stock during the service period of the award because dividend equivalent payments on performance stock units are deferred until such time that the units vest and shares are issued. The impact of forfeitures of share-based payment awards on compensation expense is recognized as forfeitures occur. We have three active stock compensation plans (the 2007 Outside Directors Incentive Plan, the 2015 Omnibus Incentive Plan, and the 2024 Equity Incentive Plan). All of the plans have been approved by our shareholders. The 2024 Equity Incentive Plan (the “2024 Plan”) was approved by our shareholders on April 24, 2024 to replace the 2015 Omnibus Incentive Plan (the “2015 Plan”). Under the 2024 Plan, shareholders approved the issuance, pursuant to the plan, of 2,576,038 shares of our common stock. This amount included 2,350,000 newly authorized shares and the 226,038 shares remaining available for issuance under the superseded 2015 Plan. The 2015 Plan had previously superseded the 2007 Outside Directors Incentive Plan (the “2007 Directors Plan”) and the 2005 Omnibus Incentive Plan, which is no longer active. Our stock compensation plans were established to (i) motivate superior performance by means of performance-related incentives, (ii) encourage and provide for the acquisition of an ownership interest in our company by employees and non-employee directors and (iii) enable us to attract and retain qualified and competent persons as employees and to serve as members of our board of directors. Under the 2024 Plan, we may grant, among other things, nonqualified stock options, incentive stock options, stock awards, stock appreciation rights, restricted stock units, performance share units or any combination thereof to certain employees and non-employee directors. Any of the authorized shares may be used for any type of award allowable under the Plan. The Compensation and Benefits Committee (“Committee”) of our Board of Directors has sole authority to (i) establish the awards to be issued, (ii) select the employees and non-employee directors to receive awards, and (iii) approve the terms and conditions of each award contract. Each award under the stock plans is evidenced by an award agreement that specifies the award price, the duration of the award, the number of shares to which the award pertains, and such other provisions as the Committee determines. For stock options, the option price for each grant is at least equal to the fair market value of a share of Cullen/Frost’s common stock on the date of grant. Options granted expire at such time as the Committee determines at the date of grant and in no event does the exercise period exceed a maximum of ten years. As defined in the plans, outstanding unvested awards may immediately vest upon a change-in-control of Cullen/Frost and subsequent termination resulting from the change in control. Director deferred stock units granted to non-employee directors generally have immediate vesting. Upon retirement from our board of directors, non-employee directors will receive one share of our common stock for each director deferred stock unit held. Non-vested restricted stock units granted to employees generally have a three four Performance stock units represent shares potentially issuable in the future. For performance stock units granted in 2024, and years prior to 2021, issuance is based upon the measure of our achievement of relative return on assets over a three-year performance period compared to an identified peer group's achievement of relative return on assets over the same three-year performance period. For performance stock units granted in 2023, 2022, and 2021, issuance is based upon the measure of our achievement of growth in adjusted net revenue, averaged over the three-year performance period, compared to the 2023, 2022, and 2021 base-year amounts, respectively. Performance stock units are eligible to receive equivalent dividend payments based on declared dividends on our common stock during the performance period. Equivalent dividend payments are based upon the ultimate number of shares issued under each performance award and are deferred until such time that the units vest and shares are issued. Options granted to employees generally have a ten four Stock-based Compensation Expense. Valuation of Stock-Based Compensation . For the purposes of recognizing stock-based compensation expense, the fair value of non-vested restricted stock units and director deferred stock units is generally the market price of the stock on the measurement date, which, for us, is the date of the award. The fair value of performance stock units is determined in a similar manner except that the market price of the stock on the measurement date is discounted by the present value of the dividends expected to be paid on our common stock during the service period of the award because dividend equivalent payments on performance stock units are deferred until such time that the units vest and shares are issued. In applying this discount to the market price of our stock on the measurement date, we assumed we would pay a flat quarterly dividend during the service period equal to our most recent dividend payment, which was $0.95, $0.92 and $0.87 in 2024, 2023 and 2022, respectively, discounted at a weighted-average risk-free rate of 4.09%, 5.01% and 4.45% in 2024, 2023 and 2022, respectively.

Fair Value Measures and Discl_2

Fair Value Measures and Disclosures (Policies)	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements . In general, fair values of financial instruments are based upon quoted market prices, where available. If such quoted market prices are not available, fair value is based upon internally developed models that primarily use, as inputs, observable market-based parameters. Valuation adjustments may be made to ensure that financial instruments are recorded at fair value. These adjustments may include amounts to reflect counterparty credit quality and our creditworthiness, among other things, as well as unobservable parameters. Any such valuation adjustments are applied consistently over time. See Note 16 - Fair Value Measurements. The fair value of an asset or liability is the price that would be received to sell that asset or paid to transfer that liability in an orderly transaction occurring in the principal market (or most advantageous market in the absence of a principal market) for such asset or liability. In estimating fair value, we utilize valuation techniques that are consistent with the market approach, the income approach and/or the cost approach. Such valuation techniques are consistently applied. Inputs to valuation techniques include the assumptions that market participants would use in pricing an asset or liability. ASC Topic 820 establishes a fair value hierarchy for valuation inputs that gives the highest priority to quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. The fair value hierarchy is as follows: • Level 1 Inputs - Unadjusted quoted prices in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. • Level 2 Inputs - Inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. These might include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (such as interest rates, volatilities, prepayment speeds, credit risks, etc.) or inputs that are derived principally from or corroborated by market data by correlation or other means. • Level 3 Inputs - Unobservable inputs for determining the fair values of assets or liabilities that reflect an entity’s own assumptions about the assumptions that market participants would use in pricing the assets or liabilities. In general, fair value is based upon quoted market prices, where available. If such quoted market prices are not available, fair value is based upon internally developed models that primarily use, as inputs, observable market- based parameters. Valuation adjustments may be made to ensure that financial instruments are recorded at fair value. These adjustments may include amounts to reflect counterparty credit quality and our creditworthiness, among other things, as well as unobservable parameters. Any such valuation adjustments are applied consistently over time. Our valuation methodologies may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. While management believes our valuation methodologies are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different estimate of fair value at the reporting date. Furthermore, the reported fair value amounts have not been comprehensively revalued since the presentation dates, and therefore, estimates of fair value after the balance sheet date may differ significantly from the amounts presented herein. A more detailed description of the valuation methodologies used for assets and liabilities measured at fair value is set forth below. Transfers between levels of the fair value hierarchy are recognized on the actual date of the event or circumstances that caused the transfer, which generally coincides with our monthly and/or quarterly valuation process. Financial Assets and Financial Liabilities: Financial assets and financial liabilities measured at fair value on a recurring basis include the following: Securities Available for Sale . U.S. Treasury securities are reported at fair value utilizing Level 1 inputs. Other securities classified as available for sale are reported at fair value utilizing Level 2 inputs. For these securities, 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. We review the prices supplied by the independent pricing service, as well as their underlying pricing methodologies, for reasonableness and to ensure such prices are aligned with traditional pricing matrices. In general, we do not purchase investment portfolio securities that are esoteric or that have a complicated structure. Our entire portfolio consists of traditional investments, nearly all of which are U.S. Treasury obligations, federal agency bullet or mortgage pass-through securities, or general obligation or revenue based municipal bonds. Pricing for such instruments is fairly generic and is easily obtained. From time to time, we will validate prices supplied by the independent pricing service by comparison to prices obtained from third-party sources or derived using internal models. Trading Securities . U.S. Treasury securities and exchange-listed common stock are reported at fair value utilizing Level 1 inputs. Other securities classified as trading are reported at fair value utilizing Level 2 inputs in the same manner as described above for securities available for sale. Derivatives . Derivatives are generally reported at fair value utilizing Level 2 inputs. We utilize internal valuation methods with observable market data inputs to estimate the fair values of our outstanding interest rate, commodity and foreign currency derivative contracts. We also obtain dealer quotations and/or utilize third-party models for comparative purposes to assess the reasonableness of our model valuations. Though there has never been a significant discrepancy in the valuations, should such a significant discrepancy arise, we would obtain price verification from a third-party dealer. In cases where significant credit valuation adjustments are incorporated into the estimation of fair value, reported amounts are considered to have been derived utilizing Level 3 inputs. For purposes of potential valuation adjustments to our derivative positions, we evaluate the credit risk of our counterparties as well as ours. Accordingly, we have considered factors such as the likelihood of our default and the default of our counterparties, our net exposures and remaining contractual life, among other things, in determining if any fair value adjustments related to credit risk are required. Counterparty exposure is evaluated by netting positions that are subject to master netting arrangements, as well as considering the amount of collateral securing the position. We review our counterparty exposure on a regular basis, and, when necessary, appropriate business actions are taken to adjust the exposure. We also utilize this approach to estimate our own credit risk on derivative liability positions. To date, we have not realized any significant losses due to a counterparty’s inability to pay any net uncollateralized position. The change in value of derivative assets and derivative liabilities attributable to credit risk was not significant during the reported periods. Certain financial assets and financial liabilities are measured at fair value on a nonrecurring basis; that is, the instruments are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (for example, when there is evidence of impairment). Financial assets measured at fair value on a non-recurring basis during the reported periods include certain loans reported at the fair value of the underlying collateral if repayment is expected solely from the collateral. Collateral values are estimated using Level 2 inputs based on observable market data, typically in the case of real estate collateral, or Level 3 inputs based on customized discounting criteria, typically in the case of non-real estate collateral such as inventory, oil and gas reserves, accounts receivable, equipment or other business assets. Non-Financial Assets and Non-Financial Liabilities: We do not have any non-financial assets or non-financial liabilities measured at fair value on a recurring basis. From time to time, non-financial assets measured at fair value on a non-recurring basis may include certain foreclosed assets which, upon initial recognition, were remeasured and reported at fair value through a charge-off to the allowance for loan losses and certain foreclosed assets which, subsequent to their initial recognition, were remeasured at fair value through a write-down included in other non-interest expense. The fair value of a foreclosed asset is estimated using Level 2 inputs based on observable market data or Level 3 inputs based on customized discounting criteria. During the reported periods, all fair value measurements for foreclosed assets utilized Level 2 inputs. The following table presents foreclosed assets that were remeasured and reported at fair value: 2024 2023 2022 Foreclosed assets remeasured at initial recognition: Carrying value of foreclosed assets prior to remeasurement $ 19,297 $ — $ 239 Charge-offs recognized in the allowance for credit losses on loans (3,797) — — Fair value $ 15,500 $ — $ 239 Charge-offs recognized upon loan foreclosures are generally offset by general or specific allocations of the allowance for credit losses on loans and generally do not, and did not during the reported periods, significantly impact our credit loss expense. Regulatory guidelines require us to reevaluate the fair value of other real estate owned on at least an annual basis. While our policy is to comply with the regulatory guidelines, our general practice is to reevaluate the fair value of collateral supporting collateral dependent loans on a quarterly basis. Thus, appraisals are generally not considered to be outdated, and we typically do not make any adjustments to the appraised values. ASC Topic 825, “Financial Instruments,” requires disclosure of the fair value of financial assets and financial liabilities, including those financial assets and financial liabilities that are not measured and reported at fair value on a recurring basis or non-recurring basis. The estimated fair value approximates carrying value for cash and cash equivalents, accrued interest and the cash surrender value of life insurance policies. The methodologies for other financial assets and financial liabilities that are not measured and reported at fair value on a recurring basis or non-recurring basis are discussed below: Loans . The estimated fair value approximates carrying value for variable-rate loans that reprice frequently and with no significant change in credit risk. The fair value of fixed-rate loans and variable-rate loans which reprice on an infrequent basis is estimated by discounting future cash flows using the current interest rates at which similar loans with similar terms would be made to borrowers of similar credit quality. An overall valuation adjustment is made for specific credit risks as well as general portfolio credit risk. Deposits . The estimated fair value approximates carrying value for demand deposits. The fair value of fixed-rate deposit liabilities with defined maturities is estimated by discounting future cash flows using the interest rates currently offered for deposits of similar remaining maturities. The estimated fair value of deposits does not take into account the value of our long-term relationships with depositors, commonly known as core deposit intangibles, which are separate intangible assets, and not considered financial instruments. Nonetheless, we would likely realize a core deposit premium if our deposit portfolio were sold in the principal market for such deposits. Borrowed Funds . The estimated fair value approximates carrying value for short-term borrowings. The fair value of long-term fixed-rate borrowings is estimated using quoted market prices, if available, or by discounting future cash flows using current interest rates for similar financial instruments. The estimated fair value approximates carrying value for variable-rate junior subordinated deferrable interest debentures that reprice quarterly. Loan Commitments, Standby and Commercial Letters of Credit . Our lending commitments have variable interest rates and “escape” clauses if the customer’s credit quality deteriorates. Therefore, the fair values of these items are not significant and are not included in the following table.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Additional Cash Flow Information	Additional cash flow information was as follows: Year Ended December 31, 2024 2023 2022 Cash paid for interest $ 788,377 $ 616,274 $ 169,020 Cash paid for income tax 122,000 118,000 100,000 Significant non-cash transactions: Unsettled securities transactions 501,587 1,452 94,884 Loans foreclosed and transferred to other real estate owned and foreclosed assets 19,297 — 239 Right-of-use lease assets obtained in exchange for lessee operating lease liabilities 15,044 15,259 31,787

Securities (Tables)

Securities (Tables)	12 Months Ended
	Dec. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Held-to-maturity	A summary of the amortized cost, fair value and allowance for credit losses related to securities held to maturity as of December 31, 2024 and 2023 is presented below. Amortized Gross Gross Estimated Allowance Net December 31, 2024 Residential mortgage-backed securities $ 1,193,840 $ — $ 71,076 $ 1,122,764 $ — $ 1,193,840 States and political subdivisions 2,338,745 13,954 116,414 2,236,285 (310) 2,338,435 Other 1,500 — 3 1,497 — 1,500 Total $ 3,534,085 $ 13,954 $ 187,493 $ 3,360,546 $ (310) $ 3,533,775 December 31, 2023 Residential mortgage-backed securities $ 1,250,431 $ 76 $ 54,175 $ 1,196,332 $ — $ 1,250,431 States and political subdivisions 2,367,807 42,990 76,540 2,334,257 (310) 2,367,497 Other 1,500 — 45 1,455 — 1,500 Total $ 3,619,738 $ 43,066 $ 130,760 $ 3,532,044 $ (310) $ 3,619,428
Moody's and Standard & Poor's Bond Ratings	The following table summarizes Moody's and/or Standard & Poor's bond ratings for our portfolio of held-to-maturity securities issued by States and political subdivisions and other securities as of December 31, 2024: States and Political Subdivisions Not Guaranteed or Pre-Refunded Guaranteed by the Texas PSF Guaranteed by Third Party Pre-Refunded Total Other Aaa/AAA $ 301,310 $ 1,504,951 $ 13,640 $ 14,531 $ 1,834,432 $ — Aa/AA 498,198 — 6,115 — 504,313 — Not rated — — — — — 1,500 Total $ 799,508 $ 1,504,951 $ 19,755 $ 14,531 $ 2,338,745 $ 1,500
Debt Securities, Held-to-maturity, Allowance for Credit Loss	The following table details activity in the allowance for credit losses on held-to-maturity securities. 2024 2023 2022 Beginning balance $ 310 $ 158 $ 158 Credit loss expense (benefit) — 152 — Ending balance $ 310 $ 310 $ 158
Debt Securities, Available-for-sale	A summary of the amortized cost, fair value and allowance for credit losses related to securities available for sale as of December 31, 2024 and 2023 is presented below. Amortized Gross Gross Allowance Estimated December 31, 2024 U.S. Treasury $ 3,692,215 $ — $ 249,895 $ — $ 3,442,320 Residential mortgage-backed securities 8,024,704 2,352 1,029,154 — 6,997,902 States and political subdivisions 4,842,060 2,493 284,329 — 4,560,224 Other 43,179 — — — 43,179 Total $ 16,602,158 $ 4,845 $ 1,563,378 $ — $ 15,043,625 December 31, 2023 U.S. Treasury $ 5,212,894 $ — $ 285,305 $ — $ 4,927,589 Residential mortgage-backed securities 7,463,954 9,066 876,338 — 6,596,682 States and political subdivisions 5,245,721 5,762 240,152 — 5,011,331 Other 42,769 — — — 42,769 Total $ 17,965,338 $ 14,828 $ 1,401,795 $ — $ 16,578,371
Year End Securities with Unrealized Losses, Segregated by Length of Impairment	The table below summarizes, as of December 31, 2024, securities available for sale in an unrealized loss position for which an allowance for credit losses has not been recorded, aggregated by type of security and length of time in a continuous unrealized loss position. Less than 12 Months More than 12 Months Total Estimated Unrealized Estimated Unrealized Estimated Unrealized U.S. Treasury $ — $ — $ 3,442,320 $ 249,895 $ 3,442,320 $ 249,895 Residential mortgage-backed securities 1,289,852 26,420 4,725,498 1,002,734 6,015,350 1,029,154 States and political subdivisions 836,599 6,961 3,490,644 277,368 4,327,243 284,329 Total $ 2,126,451 $ 33,381 $ 11,658,462 $ 1,529,997 $ 13,784,913 $ 1,563,378
Amortized Cost and Estimated Fair Value of Securities, Excluding Trading Securities, Presented by Contractual Maturity	The following table summarizes the maturity distribution schedule of securities held to maturity and securities available for sale as of December 31, 2024. Mortgage-backed securities are included in maturity categories based on their stated maturity date. Expected maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations. Other securities classified as available for sale include stock in the Federal Reserve Bank and the Federal Home Loan Bank, which have no maturity date. These securities have been included in the total column only. Within 1 Year 1 - 5 Years 5 - 10 Years After 10 Years Total Held To Maturity Amortized Cost Residential mortgage-backed securities $ — $ 510,490 $ 11,244 $ 672,106 $ 1,193,840 States and political subdivisions 7,572 17,702 51,690 2,261,781 2,338,745 Other 1,500 — — — 1,500 Total $ 9,072 $ 528,192 $ 62,934 $ 2,933,887 $ 3,534,085 Estimated Fair Value Residential mortgage-backed securities $ — $ 459,859 $ 9,164 $ 653,741 $ 1,122,764 States and political subdivisions 7,570 17,695 49,489 2,161,531 2,236,285 Other 1,497 — — — 1,497 Total $ 9,067 $ 477,554 $ 58,653 $ 2,815,272 $ 3,360,546 Available For Sale Amortized Cost U. S. Treasury $ 1,096,734 $ 2,204,591 $ 198,105 $ 192,785 $ 3,692,215 Residential mortgage-backed securities 39 869 12,553 8,011,243 8,024,704 States and political subdivisions 284,652 225,414 804,372 3,527,622 4,842,060 Other — — — — 43,179 Total $ 1,381,425 $ 2,430,874 $ 1,015,030 $ 11,731,650 $ 16,602,158 Estimated Fair Value U. S. Treasury $ 1,088,890 $ 2,054,258 $ 165,031 $ 134,141 $ 3,442,320 Residential mortgage-backed securities 39 881 12,588 6,984,394 6,997,902 States and political subdivisions 284,459 222,960 765,004 3,287,801 4,560,224 Other — — — — 43,179 Total $ 1,373,388 $ 2,278,099 $ 942,623 $ 10,406,336 $ 15,043,625
Schedule of Realized Gain (Loss)	Sales of securities available for sale were as follows: 2024 2023 2022 Proceeds from sales $ 123,254 $ 1,904,067 $ — Gross realized gains 426 5,758 — Gross realized losses (522) (5,692) — Tax benefit (expense) related to securities gains/losses 20 (14) —
Investment Income	Premium amortization and discount accretion included in interest income on securities was as follows: 2024 2023 2022 Premium amortization $ (66,257) $ (85,506) $ (110,997) Discount accretion 21,044 21,613 13,597 Net (premium amortization) discount accretion $ (45,213) $ (63,893) $ (97,400)
Year End Trading Account Securities, at Estimated Fair Value	Year-end trading account securities, at estimated fair value, were as follows: 2024 2023 U.S. Treasury $ 33,910 $ 30,265 States and political subdivisions — 1,452 Total $ 33,910 $ 31,717
Net Gains and Losses on Trading Account Securities	Net gains and losses on trading account securities included in other non-interest income were as follows: 2024 2023 2022 Net gain on sales transactions $ 4,876 $ 3,843 $ 3,129 Net mark-to-market gains (losses) (109) (33) (230) Net gain on trading account securities $ 4,767 $ 3,810 $ 2,899

Loans (Tables)

Loans (Tables)	12 Months Ended
	Dec. 31, 2024
Receivables [Abstract]
Loans	Year-end loans, including leases net of unearned discounts, consisted of the following: 2024 2023 Commercial and industrial $ 6,109,532 $ 5,967,182 Energy: Production 903,654 681,568 Service 203,629 194,126 Other 21,612 61,043 Total energy 1,128,895 936,737 Commercial real estate: Commercial mortgages 7,165,220 6,746,709 Construction 2,264,076 1,680,724 Land 539,227 555,211 Total commercial real estate 9,968,523 8,982,644 Consumer real estate: Home equity lines of credit 911,239 792,876 Home equity loans 914,738 694,966 Home improvement loans 852,536 765,887 1-4 family mortgage loans 259,456 38,923 Other 165,420 168,074 Total consumer real estate 3,103,389 2,460,726 Total real estate 13,071,912 11,443,370 Consumer and other 444,474 476,962 Total loans $ 20,754,813 $ 18,824,251
Activities in Related Party Loans	Activity in related party loans during 2024 is presented in the following table. Other changes were primarily related to changes in related-party status. Beginning balance $ 416,107 Principal additions 306,414 Principal payments (296,754) Other changes (129,931) Ending balance $ 295,836
Non-Accrual Loans, Segregated by Class of Loans	Year-end non-accrual loans, segregated by class of loans, were as follows: December 31, 2024 December 31, 2023 Total Non-Accrual Non-Accrual with No Credit Loss Allowance Total Non-Accrual Non-Accrual with No Credit Loss Allowance Commercial and industrial $ 46,004 $ 8,800 $ 19,545 $ 5,391 Energy 4,079 1,377 11,500 7,398 Commercial real estate: Buildings, land and other 21,920 18,660 22,420 4,983 Construction — — — — Consumer real estate 6,511 4,048 7,442 5,160 Consumer and other 352 — — — Total $ 78,866 $ 32,885 $ 60,907 $ 22,932
Financing Receivable, Non-Accrual Loans, Segregated by Class of Loan and Year of Origination	The following tables present non-accrual loans as of December 31, 2024 and December 31, 2023 by class and year of origination. December 31, 2024 2024 2023 2022 2021 2020 Prior Revolving Loans Revolving Loans Converted to Term Total Commercial and industrial $ 20,819 $ 2,915 $ 4,053 $ 1,592 $ 335 $ 2,144 $ 1,186 $ 12,960 $ 46,004 Energy — — — — 56 1,321 2,702 — 4,079 Commercial real estate: Buildings, land and other 7,856 2,671 3,233 2,753 1,248 1,505 — 2,654 21,920 Construction — — — — — — — — — Consumer real estate — 47 — — 92 2,202 587 3,583 6,511 Consumer and other — 352 — — — — — — 352 Total $ 28,675 $ 5,985 $ 7,286 $ 4,345 $ 1,731 $ 7,172 $ 4,475 $ 19,197 $ 78,866 December 31, 2023 2023 2022 2021 2020 2019 Prior Revolving Loans Revolving Loans Converted to Term Total Commercial and industrial $ — $ 359 $ 1,635 $ 985 $ 1,257 $ 1,006 $ 9 $ 14,294 $ 19,545 Energy 5,875 — — 56 1,321 — 4,102 146 11,500 Commercial real estate: Buildings, land and other 20,099 — 150 — 1,451 720 — — 22,420 Construction — — — — — — — — — Consumer real estate — — — 38 2,281 483 1,600 3,040 7,442 Consumer and other — — — — — — — — — Total $ 25,974 $ 359 $ 1,785 $ 1,079 $ 6,310 $ 2,209 $ 5,711 $ 17,480 $ 60,907
Age Analysis of Past Due Loans, Segregated by Class of Loans	An age analysis of past due loans (including both accruing and non-accruing loans), segregated by class of loans, as of December 31, 2024 is presented in the following table. Loans Loans Total Past Current Total Loans Accruing Commercial and industrial $ 37,130 $ 28,120 $ 65,250 $ 6,044,282 $ 6,109,532 $ 7,685 Energy 4,263 4,079 8,342 1,120,553 1,128,895 — Commercial real estate: Buildings, land and other 37,525 13,040 50,565 7,653,882 7,704,447 1,523 Construction 870 — 870 2,263,206 2,264,076 — Consumer real estate 17,015 12,028 29,043 3,074,346 3,103,389 5,681 Consumer and other 6,693 822 7,515 436,959 444,474 822 Total $ 103,496 $ 58,089 $ 161,585 $ 20,593,228 $ 20,754,813 $ 15,711
Modification to Borrowers Experiencing Financial Difficulty	The period-end balance of loan modifications, segregated by type of modification, to borrowers experiencing financial difficulty during 2024 and 2023 are set forth in the table below, regardless of whether such modifications resulted in a new loan. There were $44.1 million in commitments to lend additional funds to these borrowers at December 31, 2024. Payment Percent of Combination: Payment Delay and Term Extension Percent of Interest Rate Reduction Percent of December 31, 2024 Commercial and industrial $ 6,126 0.1 % $ 45,835 0.8 % $ — — % Commercial real estate: Buildings, land, and other 2,012 — — — 31,302 0.4 $ 8,138 — $ 45,835 0.2 $ 31,302 0.2 Payment Percent of Combination: Payment Delay and Term Extension Percent of Combination: Interest Rate Reduction and Term Extension Percent of December 31, 2023 Commercial and industrial $ — — $ 13,813 0.2 $ — — Commercial real estate: Buildings, land, and other — — 19,438 0.3 2,092 — $ — — $ 33,251 0.2 $ 2,092 —
Financing Receivables, Modified Loans by Type of Modification	Information as of or for the years ended December 31, 2024, 2023, or 2022 related to loans modified (by type of modification) in the preceding twelve months, respectively, whereby the borrower was experiencing financial difficulty at the time of modification is set forth in the following table. Payment Combination: Payment Delay and Term Extension 2024 Past due in excess of 90 days or on non-accrual status at period-end: Commercial and industrial $ 1,693 $ — Commercial real estate: Buildings, land, and other 2,012 — $ 3,705 $ — 2023 Past due in excess of 90 days or on non-accrual status at period-end: Commercial and industrial $ — $ 13,813 Commercial real estate: Buildings, land, and other — 19,438 $ — $ 33,251 2022 Past due in excess of 90 days or on non-accrual status at period-end: Commercial real estate: Buildings, land, and other $ 1,051 $ — $ 1,051 $ — Charge-offs during the period: Commercial real estate: Buildings, land, and other $ 371 $ 352 $ 371 $ 352 Proceeds from sales: Commercial real estate: Buildings, land, and other $ — $ 1,070 $ — $ 1,070
Weighted Average Risk Grades for All Commercial Loans by Class and Year of Origination	The following tables present weighted-average risk grades for all commercial loans, by class and year of origination/renewal as of December 31, 2024 and 2023. December 31, 2024 2024 2023 2022 2021 2020 Prior Revolving Loans Revolving Loans Converted to Term Total Commercial and industrial Risk grades 1-8 $ 1,553,200 $ 513,073 $ 385,824 $ 257,280 $ 298,912 $ 253,018 $ 2,242,193 $ 50,257 $ 5,553,757 Risk grade 9 15,552 24,059 58,521 25,818 3,796 9,959 109,594 15,147 262,446 Risk grade 10 4,992 9,269 42,146 2,112 918 12,290 15,332 1,876 88,935 Risk grade 11 35,583 18,057 17,673 2,987 4,675 2,092 44,926 32,397 158,390 Risk grade 12 13,107 2,443 2,574 1,564 324 2,144 1,179 9,404 32,739 Risk grade 13 7,712 472 1,479 28 11 — 7 3,556 13,265 $ 1,630,146 $ 567,373 $ 508,217 $ 289,789 $ 308,636 $ 279,503 $ 2,413,231 $ 112,637 $ 6,109,532 W/A risk grade 6.73 7.12 7.52 7.13 5.58 6.11 6.30 9.12 6.64 Energy Risk grades 1-8 $ 387,904 $ 22,510 $ 35,357 $ 16,150 $ 1,516 $ 2,648 $ 639,362 $ 5,872 $ 1,111,319 Risk grade 9 — 1,677 662 2,011 — 398 5,035 1,400 11,183 Risk grade 10 — — 52 — — — — — 52 Risk grade 11 188 — 2,038 — 36 — — — 2,262 Risk grade 12 — — — — 56 1,321 2 — 1,379 Risk grade 13 — — — — — — 2,700 — 2,700 $ 388,092 $ 24,187 $ 38,109 $ 18,161 $ 1,608 $ 4,367 $ 647,099 $ 7,272 $ 1,128,895 W/A risk grade 6.16 7.14 7.53 4.75 6.47 8.97 5.05 7.31 5.58 Commercial real estate: Buildings, land, other Risk grades 1-8 $ 1,427,212 $ 1,288,934 $ 1,450,649 $ 1,006,922 $ 668,316 $ 965,448 $ 204,577 $ 91,444 $ 7,103,502 Risk grade 9 9,347 18,408 56,419 72,096 11,197 35,661 4,968 3,718 211,814 Risk grade 10 570 31,596 64,063 55,512 10,546 10,746 — — 173,033 Risk grade 11 5,764 5,739 63,772 23,594 13,027 82,282 — — 194,178 Risk grade 12 7,856 2,671 3,233 2,531 1,126 1,505 — 2,373 21,295 Risk grade 13 — — — 222 122 — — 281 625 $ 1,450,749 $ 1,347,348 $ 1,638,136 $ 1,160,877 $ 704,334 $ 1,095,642 $ 209,545 $ 97,816 $ 7,704,447 W/A risk grade 7.16 7.32 7.39 7.52 7.05 7.17 6.01 6.80 7.25 Construction Risk grades 1-8 $ 615,683 $ 601,151 $ 427,984 $ 59,895 $ 2,727 $ 559 $ 151,846 $ 159 $ 1,860,004 Risk grade 9 46,456 9,283 65,590 35,006 — — 15,276 — 171,611 Risk grade 10 107,666 — 48,001 76,794 — — — — 232,461 Risk grade 11 — — — — — — — — — Risk grade 12 — — — — — — — — — Risk grade 13 — — — — — — — — — $ 769,805 $ 610,434 $ 541,575 $ 171,695 $ 2,727 $ 559 $ 167,122 $ 159 $ 2,264,076 W/A risk grade 7.82 7.35 7.99 8.85 7.39 7.65 6.46 6.98 7.71 Total commercial real estate $ 2,220,554 $ 1,957,782 $ 2,179,711 $ 1,332,572 $ 707,061 $ 1,096,201 $ 376,667 $ 97,975 $ 9,968,523 W/A risk grade 7.39 7.33 7.54 7.69 7.06 7.17 6.21 6.80 7.35 December 31, 2023 2023 2022 2021 2020 2019 Prior Revolving Loans Revolving Loans Converted to Term Total Commercial and industrial Risk grades 1-8 $ 1,489,026 $ 706,210 $ 458,855 $ 349,744 $ 172,656 $ 206,643 $ 2,083,490 $ 41,254 $ 5,507,878 Risk grade 9 57,625 42,618 12,258 4,952 1,641 10,383 70,142 5,625 205,244 Risk grade 10 63,205 2,222 1,307 911 4,005 581 35,977 1,046 109,254 Risk grade 11 9,450 16,837 25,932 7,854 2,530 1,153 58,134 3,371 125,261 Risk grade 12 — 359 1,635 950 1,257 1,006 1 11,894 17,102 Risk grade 13 — — — 35 — — 8 2,400 2,443 $ 1,619,306 $ 768,246 $ 499,987 $ 364,446 $ 182,089 $ 219,766 $ 2,247,752 $ 65,590 $ 5,967,182 W/A risk grade 6.53 7.05 7.26 5.87 6.01 6.04 6.50 8.48 6.60 Energy Risk grades 1-8 $ 270,710 $ 54,185 $ 75,004 $ 3,673 $ 1,819 $ 4,047 $ 451,897 $ 9,886 $ 871,221 Risk grade 9 1,137 7,315 1,041 — 456 — 17,680 14 27,643 Risk grade 10 — — 33 — 291 494 — — 818 Risk grade 11 — — 25 106 2,989 — 21,650 785 25,555 Risk grade 12 5,875 — — 56 1,321 — 1,402 146 8,800 Risk grade 13 — — — — — — 2,700 — 2,700 $ 277,722 $ 61,500 $ 76,103 $ 3,835 $ 6,876 $ 4,541 $ 495,329 $ 10,831 $ 936,737 W/A risk grade 6.19 7.07 6.00 6.99 10.02 7.07 5.75 7.33 6.05 Commercial real estate: Buildings, land, other Risk grades 1-8 $ 1,601,175 $ 1,667,750 $ 1,186,559 $ 747,289 $ 503,303 $ 874,942 $ 214,874 $ 99,466 $ 6,895,358 Risk grade 9 12,173 68,007 28,870 13,250 16,272 23,214 11,143 541 173,470 Risk grade 10 7,671 29,278 17,364 34,672 747 3,153 3,716 — 96,601 Risk grade 11 4,105 20,589 20,119 16,363 793 51,739 — 363 114,071 Risk grade 12 17,449 — 150 — 1,451 720 — — 19,770 Risk grade 13 2,650 — — — — — — — 2,650 $ 1,645,223 $ 1,785,624 $ 1,253,062 $ 811,574 $ 522,566 $ 953,768 $ 229,733 $ 100,370 $ 7,301,920 W/A risk grade 7.23 7.18 7.29 7.22 6.90 7.16 7.49 6.77 7.20 Construction Risk grades 1-8 $ 538,072 $ 537,705 $ 264,770 $ 28,063 $ 296 $ 1,613 $ 155,567 $ — $ 1,526,086 Risk grade 9 3,414 35,565 79,871 — — — 8,252 — 127,102 Risk grade 10 13,322 — — — — — 3,713 — 17,035 Risk grade 11 5,912 3,104 — — — — 1,485 — 10,501 Risk grade 12 — — — — — — — — — Risk grade 13 — — — — — — — — — $ 560,720 $ 576,374 $ 344,641 $ 28,063 $ 296 $ 1,613 $ 169,017 $ — $ 1,680,724 W/A risk grade 7.44 7.44 7.93 2.55 7.22 6.78 7.34 — 7.45 Total commercial real estate $ 2,205,943 $ 2,361,998 $ 1,597,703 $ 839,637 $ 522,862 $ 955,381 $ 398,750 $ 100,370 $ 8,982,644 W/A risk grade 7.28 7.24 7.43 7.07 6.90 7.15 7.43 6.77 7.24
Age analysis of Past Due Consumer Loans by Class and Year of Origination	Information about the payment status of consumer loans, segregated by portfolio segment and year of origination, as of December 31, 2024 and December 31, 2023 was as follows: December 31, 2024 2024 2023 2022 2021 2020 Prior Revolving Loans Revolving Loans Converted to Term Total Consumer real estate: Past due 30-89 days $ 632 $ 1,030 $ 1,897 $ 965 $ 645 $ 1,944 $ 9,790 $ 112 $ 17,015 Past due 90 or more days — 292 972 1,165 213 3,255 2,452 3,679 12,028 Total past due 632 1,322 2,869 2,130 858 5,199 12,242 3,791 29,043 Current loans 699,196 544,811 387,344 248,225 146,972 152,517 886,848 8,433 3,074,346 Total $ 699,828 $ 546,133 $ 390,213 $ 250,355 $ 147,830 $ 157,716 $ 899,090 $ 12,224 $ 3,103,389 Consumer and other: Past due 30-89 days $ 3,378 $ 772 $ 249 $ 22 $ 66 $ 23 $ 1,734 $ 449 $ 6,693 Past due 90 or more days 243 — — — — 3 395 181 822 Total past due 3,621 772 249 22 66 26 2,129 630 7,515 Current loans 54,440 27,705 9,276 3,006 1,906 1,124 315,038 24,464 436,959 Total $ 58,061 $ 28,477 $ 9,525 $ 3,028 $ 1,972 $ 1,150 $ 317,167 $ 25,094 $ 444,474 December 31, 2023 2023 2022 2021 2020 2019 Prior Revolving Loans Revolving Loans Converted to Term Total Consumer real estate: Past due 30-89 days $ 874 $ 2,066 $ 1,318 $ 959 $ 537 $ 2,641 $ 3,570 $ 539 $ 12,504 Past due 90 or more days — 512 626 38 — 887 2,566 3,087 7,716 Total past due 874 2,578 1,944 997 537 3,528 6,136 3,626 20,220 Current loans 579,505 432,719 281,820 170,225 58,744 134,319 775,465 7,709 2,440,506 Total $ 580,379 $ 435,297 $ 283,764 $ 171,222 $ 59,281 $ 137,847 $ 781,601 $ 11,335 $ 2,460,726 Consumer and other: Past due 30-89 days $ 3,014 $ 488 $ 148 $ 66 $ 28 $ 40 $ 2,553 $ 158 $ 6,495 Past due 90 or more days 153 — 27 — 20 — 51 — 251 Total past due 3,167 488 175 66 48 40 2,604 158 6,746 Current loans 67,272 28,885 6,290 3,581 1,199 1,230 339,789 21,970 470,216 Total $ 70,439 $ 29,373 $ 6,465 $ 3,647 $ 1,247 $ 1,270 $ 342,393 $ 22,128 $ 476,962
Financing Receivable Revolving Loans Converted to Term	Revolving loans that converted to term during 2024 and 2023 were as follows: 2024 2023 Commercial and industrial $ 71,275 $ 28,713 Energy 2,393 6,409 Commercial real estate: Buildings, land and other 9,776 4,780 Construction 159 — Consumer real estate 3,425 2,467 Consumer and other 11,158 7,482 Total $ 98,186 $ 49,851
Financing Receivable, Allowance for Credit Loss By Loan Class Calculated in Accordance With CECL Methodology	The following table presents details of the allowance for credit losses on loans segregated by loan portfolio segment as of December 31, 2024 and 2023, calculated in accordance with the CECL methodology described above. Commercial Energy Commercial Consumer Consumer Total December 31, 2024 Modeled expected credit losses $ 51,669 $ 3,969 $ 17,549 $ 17,720 $ 7,019 $ 97,926 Q-Factor and other qualitative adjustments 22,635 3,323 125,031 620 3,095 154,704 Specific allocations 13,265 2,700 625 766 165 17,521 Total $ 87,569 $ 9,992 $ 143,205 $ 19,106 $ 10,279 $ 270,151 December 31, 2023 Modeled expected credit losses $ 50,959 $ 7,838 $ 15,443 $ 12,364 $ 5,969 $ 92,573 Q-Factor and other qualitative adjustments 20,612 7,276 112,505 433 4,071 144,897 Specific allocations 2,435 2,700 2,650 741 — 8,526 Total $ 74,006 $ 17,814 $ 130,598 $ 13,538 $ 10,040 $ 245,996
Activity in Allowance for Loan Losses by Portfolio Segment	The following table details activity in the allowance for credit losses on loans by portfolio segment for 2024, 2023 and 2022. Allocation of a portion of the allowance to one category of loans does not preclude its availability to absorb losses in other categories. Commercial Energy Commercial Consumer Consumer Total 2024 Beginning balance $ 74,006 $ 17,814 $ 130,598 $ 13,538 $ 10,040 $ 245,996 Credit loss expense (benefit) 24,494 (8,977) 16,479 9,753 23,083 64,832 Charge-offs (14,828) (79) (3,919) (4,940) (33,344) (57,110) Recoveries 3,897 1,234 47 755 10,500 16,433 Net (charge-offs) recoveries (10,931) 1,155 (3,872) (4,185) (22,844) (40,677) Ending balance $ 87,569 $ 9,992 $ 143,205 $ 19,106 $ 10,279 $ 270,151 2023 Beginning balance $ 104,237 $ 18,062 $ 90,301 $ 8,004 $ 7,017 $ 227,621 Credit loss expense (benefit) (16,709) (1,067) 40,889 6,736 23,012 52,861 Charge-offs (18,315) (518) (955) (2,883) (31,260) (53,931) Recoveries 4,793 1,337 363 1,681 11,271 19,445 Net (charge-offs) recoveries (13,522) 819 (592) (1,202) (19,989) (34,486) Ending balance $ 74,006 $ 17,814 $ 130,598 $ 13,538 $ 10,040 $ 245,996 2022 Beginning balance $ 72,091 $ 17,217 $ 144,936 $ 6,585 $ 7,837 $ 248,666 Credit loss expense (benefit) 34,479 (313) (54,775) 1,813 13,517 (5,279) Charge-offs (6,575) (371) (702) (912) (24,388) (32,948) Recoveries 4,242 1,529 842 518 10,051 17,182 Net (charge-offs) recoveries (2,333) 1,158 140 (394) (14,337) (15,766) Ending balance $ 104,237 $ 18,062 $ 90,301 $ 8,004 $ 7,017 $ 227,621
Gross Charge-Offs By Year of Origination [Table]	The following table presents year-to-date gross charge-offs by year of origination as of December 31, 2024. 2024 2023 2022 2021 2020 Prior Revolving Loans Revolving Loans Converted to Term Total Commercial and industrial $ 1,423 $ 1,820 $ 804 $ 487 $ 403 $ 625 $ 6,273 $ 2,993 $ 14,828 Energy — 79 — — — — — — 79 Commercial real estate: Buildings, land and other — 3,797 122 — — — — — 3,919 Construction — — — — — — — — — Consumer real estate — 537 315 253 — 704 3,064 67 4,940 Consumer and other 24,485 5,793 218 56 30 71 2,459 232 33,344 Total $ 25,908 $ 12,026 $ 1,459 $ 796 $ 433 $ 1,400 $ 11,796 $ 3,292 $ 57,110 In the table above, $24.2 million of the consumer and other loan charge-offs reported as 2024 originations and $5.5 million of the total reported as 2023 originations were related to deposit overdrafts.
Investment in Loans Related to the Allowance for Loan Losses by Portfolio Segment Disaggregated Based on Impairment Methodology	The following table presents loans that were evaluated for expected credit losses on an individual basis and the related specific allocations, by loan portfolio segment as of December 31, 2024 and December 31, 2023. December 31, 2024 December 31, 2023 Loan Specific Allocations Loan Specific Allocations Commercial and industrial $ 45,009 $ 13,265 $ 18,670 $ 2,435 Energy 4,078 2,700 11,353 2,700 Commercial real estate: Buildings, land and other 18,797 122 21,373 2,650 Construction 2,012 503 — — Consumer real estate 6,039 766 7,235 741 Consumer and other 352 165 — — Total $ 76,287 $ 17,521 $ 58,631 $ 8,526

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2024
Property, Plant and Equipment [Abstract]
Premises and Equipment	Year-end premises and equipment were as follows: 2024 2023 Land $ 224,290 $ 191,594 Buildings 644,240 581,745 Technology, furniture and equipment 281,697 262,666 Leasehold improvements 250,572 230,642 Construction and projects in progress 24,135 36,910 Lease right-of-use assets 270,282 280,502 1,695,216 1,584,059 Less accumulated depreciation and amortization (449,839) (394,026) Total premises and equipment, net $ 1,245,377 $ 1,190,033
Lease Commitments, Components of Lease Expense	The components of total lease expense in 2024 and 2023 were as follows: 2024 2023 Amortization of lease right-of-use assets $ 35,400 $ 34,137 Short-term lease expense 1,456 2,576 Non-lease components (including taxes, insurance, common maintenance, etc.) 12,835 13,811 Total $ 49,691 $ 50,524
Lessee, Operating Lease, Liability, Maturity	The following table reconciles future undiscounted lease payments due under non-cancelable operating leases (those amounts subject to recognition) to the aggregate operating lessee lease liability as of December 31, 2024: Future lease payments: 2025 $ 36,953 2026 37,007 2027 35,958 2028 34,007 2029 29,795 Thereafter 206,868 Total undiscounted operating lease liability 380,588 Imputed interest 72,535 Total operating lease liability included in the accompanying balance sheet $ 308,053 Weighted-average lease term in years 12.39 Weighted-average discount rate 3.39%

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2024
Deposits [Abstract]
Deposit Liabilities, Type	Year-end deposits were as follows: 2024 2023 Non-interest-bearing demand deposits $ 14,441,820 $ 14,926,094 Interest-bearing deposits: Savings and interest checking 10,310,942 10,512,637 Money market accounts 11,568,254 10,997,279 Time accounts 6,401,732 5,484,558 Total interest-bearing deposits 28,280,928 26,994,474 Total deposits $ 42,722,748 $ 41,920,568
Additional Information About Corporation's Deposits	The following table presents additional information about our year-end deposits: 2024 2023 Deposits from foreign sources (primarily Mexico) $ 1,219,463 $ 1,061,701 Non-interest-bearing public funds deposits 759,819 675,016 Interest-bearing public funds deposits 625,104 630,455 Total deposits not covered by deposit insurance 22,972,618 22,393,786 Time deposits not covered by deposit insurance 2,744,112 2,339,716 Deposits from certain directors, executive officers and their affiliates 121,113 115,798
Scheduled Maturities of Time Deposits	Scheduled maturities of time deposits at December 31, 2024 were as follows: 2025 $ 6,214,390 2026 17,636 2027 169,706 $ 6,401,732
Time Deposit Maturities	Scheduled maturities of time deposits not covered by deposit insurance at December 31, 2024, were as follows: Due within 3 months or less $ 2,500,536 Due after 3 months and within 6 months 91,140 Due after 6 months and within 12 months 107,808 Due after 12 months 44,628 $ 2,744,112

Off-Balance-Sheet Arrangement_2

Off-Balance-Sheet Arrangements, Commitments, Guarantees and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Financial Instruments With Off-Balance-Sheet Risk	Year-end financial instruments with off-balance-sheet risk are presented in the following table. Commitments and standby letters of credit are presented at contractual amounts; however, since many of these commitments are expected to expire unused or only partially used, the total amounts of these commitments do not necessarily reflect future cash requirements. 2024 2023 Commitments to extend credit $ 12,046,520 $ 12,195,073 Standby letters of credit 449,176 438,635 Deferred standby letter of credit fees 3,071 2,912
Commitments, Off-Balance-Sheet, Allowance for Credit Losses	The following table details activity in the allowance for credit losses on off-balance-sheet credit exposures. 2024 2023 2022 Beginning balance $ 51,751 $ 58,593 $ 50,314 Credit loss expense (benefit) 153 (6,842) 8,279 Ending balance $ 51,904 $ 51,751 $ 58,593

Capital and Regulatory Matters

Capital and Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2024
Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract]
Actual and Required Capital Ratios	The following table presents actual and required capital ratios as of December 31, 2024 and December 31, 2023 for Cullen/Frost and Frost Bank under the Basel III Capital Rules. Capital levels required to be considered well capitalized are based upon prompt corrective action regulations, as amended to reflect the changes under the Basel III Capital Rules. Actual Minimum Capital Required to be Considered Well Capitalized (1) Capital Ratio Capital Ratio Capital Ratio 2024 Common Equity Tier 1 to Risk-Weighted Assets Cullen/Frost $ 4,343,666 13.62 % $ 2,232,822 7.00 % N/A N/A Frost Bank 4,387,862 13.76 2,231,710 7.00 $ 2,072,302 6.50 % Tier 1 Capital to Risk-Weighted Assets Cullen/Frost 4,489,118 14.07 2,711,283 8.50 1,913,847 6.00 Frost Bank 4,387,862 13.76 2,709,934 8.50 2,550,526 8.00 Total Capital to Risk-Weighted Assets Cullen/Frost 4,954,136 15.53 3,349,232 10.50 3,189,745 10.00 Frost Bank 4,692,880 14.72 3,347,565 10.50 3,188,157 10.00 Leverage Ratio Cullen/Frost 4,489,118 8.63 2,079,715 4.00 N/A N/A Frost Bank 4,387,862 8.44 2,079,965 4.00 2,599,956 5.00 2023 Common Equity Tier 1 to Risk-Weighted Assets Cullen/Frost $ 4,036,945 13.25 % $ 2,132,516 7.00 % N/A N/A Frost Bank 4,057,111 13.33 2,129,784 7.00 $ 1,977,656 6.50 % Tier 1 Capital to Risk-Weighted Assets Cullen/Frost 4,182,397 13.73 2,589,484 8.50 1,827,871 6.00 Frost Bank 4,057,111 13.33 2,586,166 8.50 2,434,038 8.00 Total Capital to Risk-Weighted Assets Cullen/Frost 4,625,760 15.18 3,198,774 10.50 3,046,452 10.00 Frost Bank 4,320,474 14.20 3,194,676 10.50 3,042,548 10.00 Leverage Ratio Cullen/Frost 4,182,397 8.35 2,003,020 4.00 N/A N/A Frost Bank 4,057,111 8.10 2,003,152 4.00 2,503,940 5.00 ____________________ (1) “Well-capitalized” minimum Common Equity Tier 1 to Risk-Weighted Assets and Leverage Ratio are not formally defined under applicable banking regulations for bank holding companies.

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Basic and Diluted Earnings Per Common Share	The following table presents a reconciliation of net income available to common shareholders, net earnings allocated to common stock and the number of shares used in the calculation of basic and diluted earnings per common share. 2024 2023 2022 Net Income $ 582,542 $ 597,973 $ 579,150 Less: Preferred stock dividends 6,675 6,675 6,675 Net income available to common shareholders 575,867 591,298 572,475 Less: Earnings allocated to participating securities 6,236 6,283 5,210 Net earnings allocated to common stock $ 569,631 $ 585,015 $ 567,265 Distributed earnings allocated to common stock $ 239,879 $ 229,749 $ 207,924 Undistributed earnings allocated to common stock 329,752 355,266 359,341 Net earnings allocated to common stock $ 569,631 $ 585,015 $ 567,265 Weighted-average shares outstanding for basic earnings per common share 64,120,455 64,204,239 64,156,870 Dilutive effect of stock compensation 142,191 200,594 363,648 Weighted-average shares outstanding for diluted earnings per common share 64,262,646 64,404,833 64,520,518

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2024
Retirement Benefits [Abstract]
Combined Activity in Corporations Defined Benefit Pension Plans	We use a December 31 measurement date for our defined benefit plans. Combined activity in our defined benefit pension plans was as follows: 2024 2023 2022 Change in plan assets: Fair value of plan assets at beginning of year $ 174,611 $ 161,823 $ 197,747 Actual return on plan assets 5,306 22,477 (26,108) Employer contributions 1,150 1,105 1,114 Benefits paid (11,340) (10,794) (10,930) Fair value of plan assets at end of year 169,727 174,611 161,823 Change in benefit obligation: Benefit obligation at beginning of year 142,372 143,944 185,925 Interest cost 6,647 6,983 4,017 Actuarial (gain) loss (6,779) 2,239 (35,068) Benefits paid (11,340) (10,794) (10,930) Benefit obligation at end of year 130,900 142,372 143,944 Funded status of the plan at end of year and accrued benefit (liability) recognized $ 38,827 $ 32,239 $ 17,879 Accumulated benefit obligation at end of year $ 130,900 $ 142,372 $ 143,944
Disaggregated Information Related to Corporations Defined Benefit Pension Plans	Certain disaggregated information related to our defined benefit pension plans as of year-end was as follows: Retirement Plan Restoration Plan 2024 2023 2024 2023 Projected benefit obligation $ 120,179 $ 130,750 $ 10,721 $ 11,622 Accumulated benefit obligation 120,179 130,750 10,721 11,622 Fair value of plan assets 169,727 174,611 — — Funded status of the plan at end of year and accrued benefit (liability) recognized 49,548 43,861 (10,721) (11,622)
Net Periodic Benefit Cost (Benefit)	The components of the combined net periodic cost (benefit) for our defined benefit pension plans are presented in the table below. 2024 2023 2022 Expected return on plan assets, net of expenses $ (9,645) $ (10,959) $ (13,966) Interest cost on projected benefit obligation 6,647 6,983 4,017 Net amortization and deferral 1,673 3,479 2,964 Net periodic expense (benefit) $ (1,325) $ (497) $ (6,985)
Defined Benefit Pension Plans Recognized as Component of Other Comprehensive Income	Amounts related to our defined benefit pension plans recognized as a component of other comprehensive income were as follows: 2024 2023 2022 Net actuarial gain (loss) $ 4,112 $ 12,757 $ (2,041) Deferred tax (expense) benefit (863) (2,679) 429 Other comprehensive income (loss), net of tax $ 3,249 $ 10,078 $ (1,612)
Defined Benefit Pension Plans Not Recognized as Component of Combined Net Period Benefit Cost	Amounts recognized as a component of accumulated other comprehensive loss as of year-end that have not been recognized as a component of the combined net periodic benefit cost of our defined benefit pension plans are presented in the following table. 2024 2023 Net actuarial loss $ (26,806) $ (30,918) Deferred tax benefit 5,630 6,493 Amounts included in accumulated other comprehensive income/loss, net of tax (21,176) (24,425)
Weighted-Average Assumptions Used to Determine Benefit Obligations	The weighted-average assumptions used to determine the benefit obligations as of the end of the years indicated and the net periodic benefit cost for the years indicated are presented in the table below. Because the plans were frozen, increases in compensation are not considered after 2001. 2024 2023 2022 Benefit obligations: Discount rate 5.58 % 4.95 % 5.14 % Net periodic benefit cost: Discount rate 4.95 % 5.14 % 2.79 % Expected return on plan assets 5.70 7.00 7.25
Fair Value of Plan Assets	The major categories of assets in our Retirement Plan as of year-end are presented in the following table. Assets are segregated by the level of the valuation inputs within the fair value hierarchy established by ASC Topic 820 “Fair Value Measurements and Disclosures,” utilized to measure fair value (see Note 16 - Fair Value Measurements). Our Restoration Plan is unfunded. 2024 2023 Level 1: Mutual funds and ETFs $ 34,564 $ 38,793 U.S. Treasury 24,341 26,633 Common stock 14,921 13,001 Cash and cash equivalents 431 1,241 Level 2: Corporate bonds and notes 62,405 58,669 U.S. government agency securities 7,232 7,041 States and political subdivisions 25,833 29,233 Total fair value of plan assets $ 169,727 $ 174,611
Expected Future Benefit Payments Related to Defined Benefit Plans	As of December 31, 2024, expected future benefit payments related to our defined benefit plans were as follows: 2025 $ 12,080 2026 12,025 2027 11,905 2028 11,596 2029 11,488 2030 through 2034 49,199 $ 108,293
Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block]	A combined summary of activity in our active stock plans is presented in the table. Performance stock units outstanding are presented assuming attainment of the maximum payout rate as set forth by the performance criteria. The target award level for performance stock units granted in 2024, 2023 and 2022 was 21,554, 66,471 and 35,015, respectively. As of December 31, 2024, there were 2,361,570 shares remaining available for grant for future awards. Director Deferred Non-Vested Performance Stock Units Outstanding Stock Options Number of Units Weighted- Number Weighted- Number of Units Weighted- Number Weighted- January 1, 2021 56,301 $ 79.21 449,337 $ 93.05 202,460 $ 84.71 877,681 $ 69.02 Granted 5,382 133.67 119,176 142.56 52,527 133.40 — — Exercised/vested (16,022) 74.89 (97,154) 94.81 (25,180) 87.18 (261,454) 63.72 Forfeited/expired — — (6,040) 93.28 (16,058) 87.18 — — December 31, 2022 45,661 87.15 465,319 105.36 213,749 96.20 616,227 71.27 Granted 8,503 103.47 217,561 85.39 99,710 74.71 — — Exercised/vested — — (108,920) 94.00 (28,151) 85.74 (130,286) 71.37 Forfeited/expired — — (7,154) 114.53 (18,254) 85.74 — — December 31, 2023 54,164 89.71 566,806 99.77 267,054 89.99 485,941 71.25 Granted 7,997 116.84 176,892 129.44 32,334 119.17 — — Exercised/vested (9,382) 80.99 (232,617) 91.78 (45,818) 57.89 (301,965) 74.98 Forfeited/expired — — (3,219) 106.74 (22,913) 57.89 — — December 31, 2024 52,779 95.37 507,862 113.72 230,657 103.65 183,976 65.11
Shares Issued in Connection With Stock Compensation Awards	Shares issued in connection with stock compensation awards are issued from available treasury shares. If no treasury shares are available, new shares are issued from available authorized shares. Shares issued in connection with stock compensation awards along with other related information were as follows: 2024 2023 2022 New shares issued from available authorized shares — 49,887 118,389 Shares issued from available treasury stock 589,782 217,470 281,421 Total 589,782 267,357 399,810 Proceeds from stock option exercises $ 22,643 $ 9,299 $ 16,659 Intrinsic value of stock options exercised 13,454 3,614 19,616 Fair value of restricted/director deferred stock units vested 35,922 13,445 19,308
Stock-Based Compensation Expense	Stock-based compensation expense and the related income tax benefit is presented in the following table. The service period for performance stock units granted each year begins on January 1 of the following year. 2024 2023 2022 Non-vested restricted stock units $ 19,457 $ 16,734 $ 13,162 Director deferred stock units 934 880 720 Performance stock units (628) 6,976 4,440 Total $ 19,763 $ 24,590 $ 18,322 Income tax benefit $ 4,776 $ 4,120 $ 2,969
Unrecognized Stock-Based Compensation Expense	Unrecognized stock-based compensation expense and the weighted-average period over which the expense is expected to be recognized at December 31, 2024 is presented in the table below. Unrecognized stock-based compensation expense related to performance stock units is presented assuming attainment of the maximum payout rate as set forth by the performance criteria. Unrecognized Expense Weighted-Average Number of Years for Expense Recognition Non-vested restricted stock units $ 25,827 2.20 Performance stock units 12,912 2.02 Total $ 38,739

Other Non-Interest Income and_2

Other Non-Interest Income and Expense (Tables)	12 Months Ended
	Dec. 31, 2024
Other Income and Expenses [Abstract]
Other Non-Interest Income and Expense	Other non-interest income and expense totals are presented in the following table. Components of these totals exceeding 1% of the aggregate of total net interest income and total non-interest income for any of the years presented are stated separately. 2024 2023 2022 Other non-interest income: Other $ 52,060 $ 54,941 $ 45,217 Total $ 52,060 $ 54,941 $ 45,217 Other non-interest expense: Professional services $ 56,385 $ 53,932 $ 40,908 Advertising, promotions and public relations 51,403 48,608 39,994 Other 136,623 126,827 113,799 Total $ 244,411 $ 229,367 $ 194,701

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Income Tax Expense	Income tax expense was as follows: 2024 2023 2022 Current income tax expense $ 125,025 $ 129,229 $ 94,595 Deferred income tax expense (benefit) (11,600) (14,829) (4,918) Income tax expense, as reported $ 113,425 $ 114,400 $ 89,677 Effective tax rate 16.3 % 16.1 % 13.4 %
Income Tax Computed by Applying U.S. Federal Statutory Income Tax Rate	A reconciliation between reported income tax expense and the amounts computed by applying the U.S. federal statutory income tax rate of 21% to income before income taxes is presented in the following table. 2024 2023 2022 Income tax expense computed at the statutory rate $ 146,153 $ 149,598 $ 140,454 Effect of tax-exempt interest (38,498) (43,114) (50,602) Net tax benefit from stock-based compensation (3,795) (894) (4,602) Tax benefit on dividends paid in our 401k plan (2,281) (2,135) (1,854) Non-deductible FDIC premiums 5,943 5,263 3,277 Non-deductible meals and entertainment 1,861 1,692 683 Non-deductible compensation 1,629 2,591 2,250 Other 2,413 1,399 71 Income tax expense, as reported $ 113,425 $ 114,400 $ 89,677
Schedule of Deferred Tax Assets and Liabilities	Year-end deferred taxes are presented in the table below. Deferred taxes are based on the U.S. statutory federal income tax rate of 21%. 2024 2023 Deferred tax assets: Net unrealized loss on securities available for sale and transferred securities $ 327,184 $ 291,023 Allowance for credit losses 67,697 62,592 Lease liabilities under operating leases 64,691 66,442 Bonus accrual 13,753 9,680 FDIC deposit insurance special assessment 8,647 9,468 Stock-based compensation 6,321 7,712 Net actuarial loss on defined benefit post-retirement benefit plans 5,630 6,493 Deferred loan and lease origination fees 3,990 4,129 Other 6,496 5,892 Total gross deferred tax assets 504,409 463,431 Deferred tax liabilities: Right-of-use assets under operating leases (56,759) (58,905) Premises and equipment (38,352) (42,640) Intangible assets (18,048) (18,106) Defined benefit post-retirement benefit plans (13,591) (13,073) Other (2,422) (2,368) Total gross deferred tax liabilities (129,172) (135,092) Net deferred tax asset (liability) $ 375,237 $ 328,339

Other Comprehensive Income (L_2

Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Component of Other Comprehensive Income (Loss)	The tax effects allocated to each component of other comprehensive income (loss) were as follows: Before Tax Tax Expense, Net of Tax 2024 Securities available for sale and transferred securities: Change in net unrealized gain/loss during the period $ (171,662) $ (36,049) $ (135,613) Change in net unrealized gain on securities transferred to held to maturity (629) (132) (497) Reclassification adjustment for net (gains) losses included in net income 96 20 76 Total securities available for sale and transferred securities (172,195) (36,161) (136,034) Defined-benefit post-retirement benefit plans: Change in the net actuarial gain/loss 2,439 512 1,927 Reclassification adjustment for net amortization of actuarial gain/loss included in net income as a component of net periodic cost (benefit) 1,673 351 1,322 Total defined-benefit post-retirement benefit plans 4,112 863 3,249 Total other comprehensive income (loss) $ (168,083) $ (35,298) $ (132,785) Before Tax Tax Expense, Net of Tax 2023 Securities available for sale and transferred securities: Change in net unrealized gain/loss during the period $ 277,926 $ 58,364 $ 219,562 Change in net unrealized gain on securities transferred to held to maturity (649) (136) (513) Reclassification adjustment for net (gains) losses included in net income (66) (14) (52) Total securities available for sale and transferred securities 277,211 58,214 218,997 Defined-benefit post-retirement benefit plans: Change in the net actuarial gain/loss 9,278 1,948 7,330 Reclassification adjustment for net amortization of actuarial gain/loss included in net income as a component of net periodic cost (benefit) 3,479 731 2,748 Total defined-benefit post-retirement benefit plans 12,757 2,679 10,078 Total other comprehensive income (loss) $ 289,968 $ 60,893 $ 229,075 2022 Securities available for sale and transferred securities: Change in net unrealized gain/loss during the period $ (2,143,567) $ (450,149) $ (1,693,418) Change in net unrealized gain on securities transferred to held to maturity (737) (155) (582) Total securities available for sale and transferred securities (2,144,304) (450,304) (1,694,000) Defined-benefit post-retirement benefit plans: Change in the net actuarial gain/loss (5,005) (1,051) (3,954) Reclassification adjustment for net amortization of actuarial gain/loss included in net income as a component of net periodic cost (benefit) 2,964 622 2,342 Total defined-benefit post-retirement benefit plans (2,041) (429) (1,612) Total other comprehensive income (loss) $ (2,146,345) $ (450,733) $ (1,695,612)
Schedule of Accumulated Other Comprehensive Income, Net of Tax	Activity in accumulated other comprehensive income, net of tax, was as follows: Securities Defined Accumulated 2024 Beginning balance $ (1,094,794) $ (24,425) $ (1,119,219) Other comprehensive income (loss) before reclassification (136,110) 1,927 (134,183) Reclassification of amounts included in net income 76 1,322 1,398 Net other comprehensive income (loss) during period (136,034) 3,249 (132,785) Ending balance $ (1,230,828) $ (21,176) $ (1,252,004) 2023 Beginning balance $ (1,313,791) $ (34,503) $ (1,348,294) Other comprehensive income (loss) before reclassification 219,049 7,330 226,379 Reclassification of amounts included in net income (52) 2,748 2,696 Net other comprehensive income (loss) during period 218,997 10,078 229,075 Ending balance $ (1,094,794) $ (24,425) $ (1,119,219) 2022 Beginning balance $ 380,209 $ (32,891) $ 347,318 Other comprehensive income (loss) before reclassification (1,694,000) (3,954) (1,697,954) Reclassification of amounts included in net income — 2,342 2,342 Net other comprehensive income (loss) during period (1,694,000) (1,612) (1,695,612) Ending balance $ (1,313,791) $ (34,503) $ (1,348,294)

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Notional Amounts and Estimated Fair Values of Interest Rate Derivative Contracts Outstanding	The notional amounts and estimated fair values of interest rate derivative contracts outstanding are presented in the following table. The fair values of these contracts are estimated utilizing internal valuation methods with observable market data inputs, or as determined by the Chicago Mercantile Exchange (“CME”) for centrally cleared derivative contracts. CME rules legally characterize variation margin payments for centrally cleared derivatives as settlements of the derivatives' exposure rather than collateral. As a result, the variation margin payment and the related derivative instruments are considered a single unit of account for accounting and financial reporting purposes. Variation margin, as determined by the CME, is settled daily. As a result, derivative contracts that clear through the CME have an estimated fair value of zero at both December 31, 2024 and 2023. December 31, 2024 December 31, 2023 Notional Estimated Notional Estimated Non-hedging interest rate derivatives: Financial institution counterparties: Loan/lease interest rate swaps - assets $ 1,213,519 $ 63,001 $ 1,040,659 $ 58,486 Loan/lease interest rate swaps - liabilities 663,078 (9,068) 617,266 (20,293) Loan/lease interest rate caps - assets 205,164 7,053 275,000 11,747 Customer counterparties: Loan/lease interest rate swaps - assets 663,078 9,068 617,266 20,482 Loan/lease interest rate swaps - liabilities 1,213,519 (63,000) 1,040,659 (58,485) Loan/lease interest rate caps - liabilities 205,164 (7,054) 275,000 (11,747)
Schedule of Weighted-Average Rates Paid and Received for Interest Rate Swaps Outstanding	The weighted-average rates paid and received for interest rate swaps outstanding at December 31, 2024 were as follows: Weighted-Average Interest Interest Interest rate swaps: Non-hedging interest rate swaps - financial institution counterparties 5.08 % 6.26 % Non-hedging interest rate swaps - customer counterparties 6.26 5.08
Schedule of Notional Amounts and Estimated Fair Values of Commodity Derivative Positions	The notional amounts and estimated fair values of non-hedging commodity derivative contracts outstanding are presented in the following table. The fair values of these contracts are estimated utilizing internal valuation methods with observable market data inputs. December 31, 2024 December 31, 2023 Notional Notional Estimated Notional Estimated Financial institution counterparties: Oil - assets Barrels 7,097 $ 27,471 5,601 $ 37,667 Oil - liabilities Barrels 4,768 (12,897) 4,581 (18,500) Natural gas - assets MMBTUs 25,454 3,804 17,363 11,822 Natural gas - liabilities MMBTUs 26,082 (4,054) 6,462 (2,499) Customer counterparties: Oil - assets Barrels 4,872 $ 12,973 4,618 $ 18,722 Oil - liabilities Barrels 6,993 (26,753) 5,564 (36,877) Natural gas - assets MMBTUs 26,767 4,255 6,462 2,499 Natural gas - liabilities MMBTUs 24,769 (3,600) 17,363 (11,571)
Schedule of Foreign Exchange Contracts, Statement of Financial Position	The notional amounts and fair values of non-hedging foreign currency derivative contracts are presented in the following table. The fair values of these contracts are estimated utilizing internal valuation methods with observable market data inputs. December 31, 2024 December 31, 2023 Notional Notional Estimated Notional Estimated Financial institution counterparties: Forward/option contracts - assets CAD — $ — 250 $ 1 Forward/option contracts - liabilities EUR — — 3,000 (14) Forward contracts - liabilities CAD — — 250 (5) Customer counterparties: Forward/option contracts - assets EUR — — 3,000 16 Forward/option contracts - assets CAD — — 250 5 Forward contracts - liabilities CAD — — 250 —
Schedule of Amounts Included in Income Related to Interest Rate Derivatives Designated as Hedges of Fair Value	Amounts included in the consolidated statements of income related to interest rate derivatives designated as hedges of fair value were as follows: 2024 2023 2022 Commercial loan/lease interest rate swaps: Amount of gain (loss) included in interest income on loans $ — $ 16 $ (7) Amount of (gain) loss included in other non-interest expense — — 6
Schedule of Amounts Related to Non-Hedging Interest Rate and Commodity Derivatives	Amounts included in the consolidated statements of income related to non-hedging interest rate, commodity, foreign currency and other derivative instruments are presented in the table below. 2024 2023 2022 Non-hedging interest rate derivatives: Other non-interest income $ 4,304 $ 6,982 $ 1,742 Other non-interest expense 3 — — Non-hedging commodity derivatives: Other non-interest income 2,183 1,889 2,297 Non-hedging foreign currency derivatives: Other non-interest income 11 30 63

Balance Sheet Offsetting Balanc

Balance Sheet Offsetting Balance Sheet Offsetting (Tables)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instruments Eligible for Offset Consolidated Balance Sheet	Information about financial instruments that are eligible for offset in the consolidated balance sheet as of December 31, 2024 is presented in the following tables. Gross Amount Gross Amount Net Amount December 31, 2024 Financial assets: Derivatives: Loan/lease interest rate swaps and caps $ 70,054 $ — $ 70,054 Commodity swaps and options 31,275 — 31,275 Total derivatives 101,329 — 101,329 Resell agreements 9,650 — 9,650 Total $ 110,979 $ — $ 110,979 Financial liabilities: Derivatives: Loan/lease interest rate swaps $ 9,068 $ — $ 9,068 Commodity swaps and options 16,951 — 16,951 Total derivatives 26,019 — 26,019 Repurchase agreements 4,342,941 — 4,342,941 Total $ 4,368,960 $ — $ 4,368,960	Information about financial instruments that are eligible for offset in the consolidated balance sheet as of December 31, 2023 is presented in the following tables. Gross Amount Gross Amount Net Amount December 31, 2023 Financial assets: Derivatives: Loan/lease interest rate swaps and caps $ 70,233 $ — $ 70,233 Commodity swaps and options 49,489 — 49,489 Foreign currency forward/option contracts 1 — 1 Total derivatives 119,723 — 119,723 Resell agreements 84,650 — 84,650 Total $ 204,373 $ — $ 204,373 Financial liabilities: Derivatives: Loan/lease interest rate swaps $ 20,293 $ — $ 20,293 Commodity swaps and options 20,999 — 20,999 Foreign currency forward contracts 19 — 19 Total derivatives 41,311 — 41,311 Repurchase agreements 4,127,188 — 4,127,188 Total $ 4,168,499 $ — $ 4,168,499
Financial Instruments Derivative Assets Liabilities And Resell Agreements Net Of Amount Not Offset	Gross Amounts Not Offset Net Amount Financial Collateral Net December 31, 2024 Financial assets: Derivatives: Counterparty H $ 36,286 $ (10,129) $ (26,157) $ — Counterparty F 15,505 (2,322) (11,759) 1,424 Counterparty B 22,338 (4,522) (17,816) — Counterparty E 14,219 (2,109) (12,100) 10 Other counterparties 12,981 (6,632) (6,325) 24 Total derivatives 101,329 (25,714) (74,157) 1,458 Resell agreements 9,650 — (9,650) — Total $ 110,979 $ (25,714) $ (83,807) $ 1,458 Financial liabilities: Derivatives: Counterparty H $ 10,129 $ (10,129) $ — $ — Counterparty F 2,322 (2,322) — — Counterparty B 4,522 (4,522) — — Counterparty E 2,109 (2,109) — — Other counterparties 6,937 (6,632) (305) — Total derivatives 26,019 (25,714) (305) — Repurchase agreements 4,342,941 — (4,342,941) — Total $ 4,368,960 $ (25,714) $ (4,343,246) $ —	Gross Amounts Not Offset Net Amount Financial Collateral Net December 31, 2023 Financial assets: Derivatives: Counterparty H $ 36,551 $ (8,870) $ (27,170) $ 511 Counterparty F 31,202 (7,444) (22,954) 804 Counterparty B 23,829 (5,151) (18,472) 206 Counterparty E 13,271 (4,548) (8,723) — Other counterparties 14,870 (6,418) (7,520) 932 Total derivatives 119,723 (32,431) (84,839) 2,453 Resell agreements 84,650 — (84,650) — Total $ 204,373 $ (32,431) $ (169,489) $ 2,453 Financial liabilities: Derivatives: Counterparty H $ 8,870 $ (8,870) $ — $ — Counterparty F 7,444 (7,444) — — Counterparty B 5,151 (5,151) — — Counterparty E 4,548 (4,548) — — Other counterparties 15,298 (6,418) (8,580) 300 Total derivatives 41,311 (32,431) (8,580) 300 Repurchase agreements 4,127,188 — (4,127,188) — Total $ 4,168,499 $ (32,431) $ (4,135,768) $ 300
Remaining Contractual Maturity of the Securities Sold Under Agreement	The remaining contractual maturity of repurchase agreements in the consolidated balance sheets as of December 31, 2024 and December 31, 2023 is presented in the following tables. Remaining Contractual Maturity of the Agreements Overnight and Continuous Up to 30 Days 30-90 Days Greater than 90 Days Total December 31, 2024 Repurchase agreements: U.S. Treasury $ 2,170,482 $ — $ — $ — $ 2,170,482 Residential mortgage-backed securities 2,172,459 — — — 2,172,459 Total borrowings $ 4,342,941 $ — $ — $ — $ 4,342,941 Gross amount of recognized liabilities for repurchase agreements $ 4,342,941 Amounts related to agreements not included in offsetting disclosures above $ — December 31, 2023 Repurchase agreements: U.S. Treasury $ 3,300,662 $ — $ — $ — $ 3,300,662 Residential mortgage-backed securities 826,526 — — — 826,526 Total borrowings $ 4,127,188 $ — $ — $ — $ 4,127,188 Gross amount of recognized liabilities for repurchase agreements $ 4,127,188 Amounts related to agreements not included in offsetting disclosures above $ —

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Financial Assets and Financial Liabilities Measured at Fair Value on a Recurring Basis	The following tables summarize financial assets and financial liabilities measured at fair value on a recurring basis as of December 31, 2024 and 2023, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value: Level 1 Level 2 Level 3 Total 2024 Securities available for sale: U.S. Treasury $ 3,442,320 $ — $ — $ 3,442,320 Residential mortgage-backed securities — 6,997,902 — 6,997,902 States and political subdivisions — 4,560,224 — 4,560,224 Other — 43,179 — 43,179 Trading account securities: U.S. Treasury 33,910 — — 33,910 States and political subdivisions — — — — Derivative assets: Interest rate swaps, caps and floors — 79,122 — 79,122 Commodity swaps and options — 48,503 — 48,503 Foreign currency forward/option contracts — — — — Derivative liabilities: Interest rate swaps, caps and floors — 79,122 — 79,122 Commodity swaps and options — 47,304 — 47,304 Foreign currency forward/option contracts — — — — 2023 Securities available for sale: U.S. Treasury $ 4,927,589 $ — $ — $ 4,927,589 Residential mortgage-backed securities — 6,596,682 — 6,596,682 States and political subdivisions — 5,011,331 — 5,011,331 Other — 42,769 — 42,769 Trading account securities: U.S. Treasury 30,265 — — 30,265 States and political subdivisions — 1,452 — 1,452 Derivative assets: Interest rate swaps, caps and floors — 90,715 — 90,715 Commodity swaps and options — 70,710 — 70,710 Foreign currency forward contracts — 22 — 22 Derivative liabilities: Interest rate swaps, caps and floors — 90,525 — 90,525 Commodity swaps and options — 69,447 — 69,447 Foreign currency forward contracts — 19 — 19
Impaired Loans Remeasured and Reported at Fair Value of Underlying Collateral	The following table presents collateral dependent loans that were remeasured and reported at fair value through a specific allocation of the allowance for credit losses on loans based upon the fair value of the underlying collateral: 2024 2023 2022 Level 2 Carrying value before allocations $ 4,982 $ 19,719 $ 6,237 Specific (allocations) reversals of prior allocations (650) (3,391) (1,480) Fair value $ 4,332 $ 16,328 $ 4,757 Level 3 Carrying value before allocations $ 37,082 $ 15,465 $ 8,156 Specific (allocations) reversals of prior allocations (10,987) (2,344) 625 Fair value $ 26,095 $ 13,121 $ 8,781
Foreclosed Assets Remeasured And Reported At Fair Value	The following table presents foreclosed assets that were remeasured and reported at fair value: 2024 2023 2022 Foreclosed assets remeasured at initial recognition: Carrying value of foreclosed assets prior to remeasurement $ 19,297 $ — $ 239 Charge-offs recognized in the allowance for credit losses on loans (3,797) — — Fair value $ 15,500 $ — $ 239
Estimated Fair Values of Financial Instruments	The estimated fair values of financial instruments that are reported at amortized cost in our consolidated balance sheets, segregated by the level of valuation inputs within the fair value hierarchy utilized to measure fair value, were as follows: December 31, 2024 December 31, 2023 Carrying Estimated Carrying Estimated Financial assets: Level 2 inputs: Cash and cash equivalents $ 10,234,258 $ 10,234,258 $ 8,687,276 $ 8,687,276 Securities held to maturity 3,533,775 3,360,546 3,619,428 3,532,044 Accrued interest receivable 236,591 236,591 251,385 251,385 Level 3 inputs: Loans, net 20,484,662 20,066,512 18,578,255 18,117,369 Financial liabilities: Level 2 inputs: Deposits 42,722,748 42,712,907 41,920,568 41,903,580 Federal funds purchased 21,975 21,975 14,200 14,200 Repurchase agreements 4,342,941 4,342,941 4,127,188 4,127,188 Junior subordinated deferrable interest debentures 123,184 123,712 123,127 123,712 Subordinated notes 99,648 98,453 99,491 96,071 Accrued interest payable 58,870 58,870 61,222 61,222

Operating Segments (Tables)

Operating Segments (Tables)	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Summary of Operating Results by Segment	Financial results by operating segment, including significant expense categories provided to the chief operating decision maker, are detailed below. Certain prior period amounts have been reclassified to conform to the current presentation. Frost Wealth Advisors excludes off-balance-sheet managed and custody assets with a total fair value of $51.4 billion, $47.2 billion and $42.9 billion at December 31, 2024, 2023 and 2022. Banking Frost Non-Banks Consolidated 2024 Interest income $ 2,382,675 $ 7,962 $ — $ 2,390,637 Interest expense 772,075 421 13,529 786,025 Net interest income (expense) 1,610,600 7,541 (13,529) 1,604,612 Credit loss expense 64,985 — — 64,985 Net interest income after credit loss expense 1,545,615 7,541 (13,529) 1,539,627 Non-interest income: Trust and investment management fees — 167,448 (2,178) 165,270 Service charges on deposit accounts 106,217 13 — 106,230 Insurance commissions and fees 61,269 — — 61,269 Interchange and card transaction fees 21,017 — — 21,017 Other charges, commissions and fees 30,626 22,717 5 53,348 Net gain (loss) on securities transactions (96) — — (96) Other 45,790 6,011 259 52,060 Total non-interest income 264,823 196,189 (1,914) 459,098 Non-interest expense: Salaries and wages 544,843 74,928 1,623 621,394 Employee benefits 109,431 12,911 104 122,446 Net occupancy 115,136 13,615 — 128,751 Technology, furniture and equipment 142,517 5,764 206 148,487 Deposit insurance 37,203 66 — 37,269 Other 189,700 49,790 4,921 244,411 Total non-interest expense 1,138,830 157,074 6,854 1,302,758 Income (loss) before income taxes 671,608 46,656 (22,297) 695,967 Income tax expense (benefit) 110,524 9,798 (6,897) 113,425 Net income (loss) 561,084 36,858 (15,400) 582,542 Preferred stock dividends — — 6,675 6,675 Net income (loss) available to common shareholders $ 561,084 $ 36,858 $ (22,075) $ 575,867 Revenues from (expenses to) external customers $ 1,875,423 $ 203,730 $ (15,443) $ 2,063,710 Average assets (in millions) $ 49,621 $ 64 $ 9 $ 49,694 Banking Frost Non-Banks Consolidated 2023 Interest income $ 2,209,659 $ 8,057 $ — $ 2,217,716 Interest expense 647,218 437 11,397 659,052 Net interest income (expense) 1,562,441 7,620 (11,397) 1,558,664 Credit loss expense 46,171 — — 46,171 Net interest income after credit loss expense 1,516,270 7,620 (11,397) 1,512,493 Non-interest income: Trust and investment management fees — 155,278 (1,963) 153,315 Service charges on deposit accounts 93,478 26 — 93,504 Insurance commissions and fees 58,271 — — 58,271 Interchange and card transaction fees 19,419 — — 19,419 Other charges, commissions and fees 30,217 18,809 — 49,026 Net gain (loss) on securities transactions 66 — — 66 Other 49,868 4,793 280 54,941 Total non-interest income 251,319 178,906 (1,683) 428,542 Non-interest expense: Salaries and wages 480,083 66,070 1,565 547,718 Employee benefits 103,427 11,776 103 115,306 Net occupancy 109,953 14,443 — 124,396 Technology, furniture and equipment 129,042 6,054 190 135,286 Deposit insurance 76,535 54 — 76,589 Other 178,784 46,081 4,502 229,367 Total non-interest expense 1,077,824 144,478 6,360 1,228,662 Income (loss) before income taxes 689,765 42,048 (19,440) 712,373 Income tax expense (benefit) 111,145 8,830 (5,575) 114,400 Net income (loss) 578,620 33,218 (13,865) 597,973 Preferred stock dividends — — 6,675 6,675 Net income (loss) available to common shareholders $ 578,620 $ 33,218 $ (20,540) $ 591,298 Revenues from (expenses to) external customers $ 1,813,760 $ 186,526 $ (13,080) $ 1,987,206 Average assets (in millions) $ 49,536 $ 59 $ 9 $ 49,604 Banking Frost Non-Banks Consolidated 2022 Interest income $ 1,470,947 $ 4,774 $ — $ 1,475,721 Interest expense 175,480 129 8,829 184,438 Net interest income (expense) 1,295,467 4,645 (8,829) 1,291,283 Credit loss expense 3,000 — — 3,000 Net interest income after credit loss expense 1,292,467 4,645 (8,829) 1,288,283 Non-interest income: Trust and investment management fees — 156,751 (2,072) 154,679 Service charges on deposit accounts 91,851 40 — 91,891 Insurance commissions and fees 53,210 — — 53,210 Interchange and card transaction fees 18,231 — — 18,231 Other charges, commissions and fees 24,520 17,070 — 41,590 Net gain (loss) on securities transactions — — — — Other 43,064 2,013 140 45,217 Total non-interest income 230,876 175,874 (1,932) 404,818 Non-interest expense: Salaries and wages 430,660 59,988 1,448 492,096 Employee benefits 78,178 10,273 157 88,608 Net occupancy 98,916 13,579 — 112,495 Technology, furniture and equipment 115,257 5,341 173 120,771 Deposit insurance 15,569 34 — 15,603 Other 147,841 42,794 4,066 194,701 Total non-interest expense 886,421 132,009 5,844 1,024,274 Income (loss) before income taxes 636,922 48,510 (16,605) 668,827 Income tax expense (benefit) 85,127 10,187 (5,637) 89,677 Net income (loss) 551,795 38,323 (10,968) 579,150 Preferred stock dividends — — 6,675 6,675 Net income (loss) available to common shareholders $ 551,795 $ 38,323 $ (17,643) $ 572,475 Revenues from (expenses to) external customers $ 1,526,343 $ 180,519 $ (10,761) $ 1,696,101 Average assets (in millions) $ 51,448 $ 57 $ 8 $ 51,513

Condensed Financial Statement_2

Condensed Financial Statements of Parent Company (Tables)	12 Months Ended
	Dec. 31, 2024
Condensed Financial Information Disclosure [Abstract]
Schedule of Condensed Balance Sheets	Condensed Balance Sheets December 31, 2024 2023 Assets: Cash $ 334,512 $ 350,525 Total cash and cash equivalents 334,512 350,525 Investment in subsidiaries 3,828,890 3,625,951 Accrued interest receivable and other assets 1,231 1,233 Total assets $ 4,164,633 $ 3,977,709 Liabilities: Junior subordinated deferrable interest debentures, net of unamortized issuance costs $ 123,184 $ 123,127 Subordinated notes, net of unamortized issuance costs 99,648 99,491 Accrued interest payable and other liabilities 43,213 38,644 Total liabilities 266,045 261,262 Shareholders’ Equity 3,898,588 3,716,447 Total liabilities and shareholders’ equity $ 4,164,633 $ 3,977,709
Schedule of Condensed Statements of Income	Condensed Statements of Income Year Ended December 31, 2024 2023 2022 Income: Dividend income paid by Frost Bank $ 262,214 $ 279,679 $ 51,711 Dividend income paid by non-banks 268 255 109 Interest and other income — 1,929 — Total income 262,482 281,863 51,820 Expenses: Interest expense 13,529 13,304 8,829 Salaries and employee benefits 1,727 1,668 1,605 Other 7,304 6,653 6,316 Total expenses 22,560 21,625 16,750 Income before income taxes and equity in undistributed earnings of subsidiaries 239,922 260,238 35,070 Income tax benefit 6,896 5,974 5,641 Equity in undistributed earnings of subsidiaries 335,724 331,761 538,439 Net income 582,542 597,973 579,150 Preferred stock dividends 6,675 6,675 6,675 Net income available to common shareholders $ 575,867 $ 591,298 $ 572,475
Schedule of Condensed Statements of Cash Flows	Condensed Statements of Cash Flows Year Ended December 31, 2024 2023 2022 Operating Activities: Net income $ 582,542 $ 597,973 $ 579,150 Adjustments to reconcile net income to net cash provided by operating activities: Equity in undistributed earnings of subsidiaries (335,724) (331,761) (538,439) Stock-based compensation 934 880 720 Net tax benefit from stock-based compensation 463 331 472 Net change in other assets and other liabilities 4,322 19,867 (15,249) Net cash from operating activities 252,537 287,290 26,654 Investing Activities: Net cash from investing activities — — — Financing Activities: Proceeds from stock option exercises 22,643 9,299 16,659 Proceeds from stock-based compensation activities of subsidiaries 18,829 23,710 17,602 Purchase of treasury stock (60,901) (42,720) (4,391) Cash dividends paid on preferred stock (6,675) (6,675) (6,675) Cash dividends paid on common stock (242,446) (232,323) (209,780) Net cash from financing activities (268,550) (248,709) (186,585) Net change in cash and cash equivalents (16,013) 38,581 (159,931) Cash and cash equivalents at beginning of year 350,525 311,944 471,875 Cash and cash equivalents at end of year $ 334,512 $ 350,525 $ 311,944

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Narrative) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash collateral on deposit	$ 350	$ 8,600
Foreclosed assets	14,100	725
Real Estate Owned, Valuation Allowance, Provision	$ 0	$ 0	$ 0
Amount of significant concentrations of any properties with write downs from any single geographic region	0%	0%	0%
Minimum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Range of change in fair value of derivative hedging instrument to be considered highly effective	80%
Maximum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Range of change in fair value of derivative hedging instrument to be considered highly effective	125%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies (Additional Cash Flow Information) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Cash paid for interest	$ 788,377	$ 616,274	$ 169,020
Cash paid for income tax	122,000	118,000	100,000
Unsettled securities transactions	501,587	1,452	94,884
Loans foreclosed and transferred to other real estate owned and foreclosed assets	19,297	0	239
Right-of-use lease assets obtained in exchange for lessee operating lease liabilities	$ 15,044	$ 15,259	$ 31,787

Securities (Narrative) (Detail)

Securities (Narrative) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Schedule Of Marketable Securities [Line Items]
Net unamortized, unrealized gain on transferred securities included in accumulated other comprehensive income, pre tax	$ 522	$ 1,200
Net unamortized, unrealized gain on transferred securities included in accumulated other comprehensive income, net of tax	412	909
Debt Securities, Held-to-maturity, 90 Days or More Past Due, Still Accruing	0
Securities held to maturity, net of allowance for credit losses of $310 at both 2024 and 2023	$ 310	310
Percent Municipal Bond Portfolio Issued By Political Subdivision Or Agencies Within State Of Texas Guaranteed By Texas Permanent School Fund Or Have Been Pre-Refunded	70.60%
Debt Securities, Available-for-sale, Allowance for Credit Loss	$ 0	0
Debt Securities [Member]
Schedule Of Marketable Securities [Line Items]
Securities held to maturity, net of allowance for credit losses of $310 at both 2024 and 2023	310	310	$ 158	$ 158
Held-to-maturity Securities [Member]
Schedule Of Marketable Securities [Line Items]
Carry value of securities pledged	1,400,000	1,000,000
Accrued interest receivable	37,800	40,900
Guaranteed by the Texas PSF [Member] | Debt Securities [Member]
Schedule Of Marketable Securities [Line Items]
Securities held to maturity, net of allowance for credit losses of $310 at both 2024 and 2023	0
Pre-Refunded [Member] | Debt Securities [Member]
Schedule Of Marketable Securities [Line Items]
Securities held to maturity, net of allowance for credit losses of $310 at both 2024 and 2023	0
Available-for-sale Securities [Member]
Schedule Of Marketable Securities [Line Items]
Carry value of securities pledged	6,200,000	6,100,000
Accrued interest receivable	$ 104,900	$ 114,900

Securities (Year End Securities

Securities (Year End Securities Held to Maturity) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Schedule of Investments [Line Items]
Held to Maturity, Amortized Cost	$ 3,534,085	$ 3,619,738
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	13,954	43,066
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	187,493	130,760
Debt Securities, Held to Maturity, Estimated Fair Value	3,360,546	3,532,044
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(310)	(310)
Securities held to maturity, net of allowance for credit losses of $310 at both 2024 and 2023	3,533,775	3,619,428
Residential Mortgage Backed Securities [Member]
Schedule of Investments [Line Items]
Held to Maturity, Amortized Cost	1,193,840	1,250,431
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0	76
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	71,076	54,175
Debt Securities, Held to Maturity, Estimated Fair Value	1,122,764	1,196,332
Debt Securities, Held-to-maturity, Allowance for Credit Loss	0	0
Securities held to maturity, net of allowance for credit losses of $310 at both 2024 and 2023	1,193,840	1,250,431
States and Political Subdivisions [Member]
Schedule of Investments [Line Items]
Held to Maturity, Amortized Cost	2,338,745	2,367,807
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	13,954	42,990
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	116,414	76,540
Debt Securities, Held to Maturity, Estimated Fair Value	2,236,285	2,334,257
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(310)	(310)
Securities held to maturity, net of allowance for credit losses of $310 at both 2024 and 2023	2,338,435	2,367,497
Other [Member]
Schedule of Investments [Line Items]
Held to Maturity, Amortized Cost	1,500	1,500
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	3	45
Debt Securities, Held to Maturity, Estimated Fair Value	1,497	1,455
Debt Securities, Held-to-maturity, Allowance for Credit Loss	0	0
Securities held to maturity, net of allowance for credit losses of $310 at both 2024 and 2023	$ 1,500	$ 1,500

Securities (Securities Moody's

Securities (Securities Moody's and Standard & Poor's Bond Rating) (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	$ 3,534,085	$ 3,619,738
States and Political Subdivisions [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	2,338,745	2,367,807
States and Political Subdivisions [Member] | Not Guaranteed or Pre-Refunded [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	799,508
States and Political Subdivisions [Member] | Guaranteed by the Texas PSF [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	1,504,951
States and Political Subdivisions [Member] | Guaranteed by Third Party
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	19,755
States and Political Subdivisions [Member] | Pre-Refunded [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	14,531
Other [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	1,500	$ 1,500
Aaa/AAA [Member] | States and Political Subdivisions [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	1,834,432
Aaa/AAA [Member] | States and Political Subdivisions [Member] | Not Guaranteed or Pre-Refunded [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	301,310
Aaa/AAA [Member] | States and Political Subdivisions [Member] | Guaranteed by the Texas PSF [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	1,504,951
Aaa/AAA [Member] | States and Political Subdivisions [Member] | Guaranteed by Third Party
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	13,640
Aaa/AAA [Member] | States and Political Subdivisions [Member] | Pre-Refunded [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	14,531
Aaa/AAA [Member] | Other [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	0
Aa/AA [Member] | States and Political Subdivisions [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	504,313
Aa/AA [Member] | States and Political Subdivisions [Member] | Not Guaranteed or Pre-Refunded [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	498,198
Aa/AA [Member] | States and Political Subdivisions [Member] | Guaranteed by the Texas PSF [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	0
Aa/AA [Member] | States and Political Subdivisions [Member] | Guaranteed by Third Party
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	6,115
Aa/AA [Member] | States and Political Subdivisions [Member] | Pre-Refunded [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	0
Aa/AA [Member] | Other [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	0
Not rated [Member] | States and Political Subdivisions [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	0
Not rated [Member] | States and Political Subdivisions [Member] | Not Guaranteed or Pre-Refunded [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	0
Not rated [Member] | States and Political Subdivisions [Member] | Guaranteed by the Texas PSF [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	0
Not rated [Member] | States and Political Subdivisions [Member] | Guaranteed by Third Party
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	0
Not rated [Member] | States and Political Subdivisions [Member] | Pre-Refunded [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	0
Not rated [Member] | Other [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to Maturity, Amortized Cost	$ 1,500

Securities (Securities Held to

Securities (Securities Held to Maturity Allowance for Credit Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, net of allowance for credit losses of $310 at both 2024 and 2023	$ 310	$ 310
Debt Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Securities held to maturity, net of allowance for credit losses of $310 at both 2024 and 2023	310	310	$ 158	$ 158
Debt Securities, Held-to-maturity, Allowance for Credit Loss, Period Increase (Decrease)	$ 0	$ 152	$ 0

Securities (Securities Availabl

Securities (Securities Available for Sale) (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 16,602,158	$ 17,965,338
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	4,845	14,828
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	1,563,378	1,401,795
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale	15,043,625	16,578,371
US Treasury [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	3,692,215	5,212,894
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	249,895	285,305
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale	3,442,320	4,927,589
Residential Mortgage Backed Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	8,024,704	7,463,954
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	2,352	9,066
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	1,029,154	876,338
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale	6,997,902	6,596,682
States and Political Subdivisions [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	4,842,060	5,245,721
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	2,493	5,762
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	284,329	240,152
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale	4,560,224	5,011,331
Other [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	43,179	42,769
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale	$ 43,179	$ 42,769

Securities (Year End Securiti_2

Securities (Year End Securities with Unrealized Losses Segregated by Length of Impairment) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Schedule of Available-for-Sale Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 2,126,451
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	33,381
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	11,658,462
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,529,997
Available for Sale, Total Estimated Fair Value	13,784,913
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	1,563,378	$ 1,401,795
US Treasury [Member]
Schedule of Available-for-Sale Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	3,442,320
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	249,895
Available for Sale, Total Estimated Fair Value	3,442,320
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	249,895	285,305
Residential Mortgage Backed Securities [Member]
Schedule of Available-for-Sale Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,289,852
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	26,420
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	4,725,498
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,002,734
Available for Sale, Total Estimated Fair Value	6,015,350
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	1,029,154	876,338
States and Political Subdivisions [Member]
Schedule of Available-for-Sale Securities [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	836,599
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	6,961
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	3,490,644
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	277,368
Available for Sale, Total Estimated Fair Value	4,327,243
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	$ 284,329	$ 240,152

Securities (Amortized Cost and

Securities (Amortized Cost and Estimated Fair Value of Securities Excluding Trading Securities Presented by Contractual Maturity) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Schedule of Available-for-Sale Securities [Line Items]
Held to Maturity, Due in one year or less, Amortized Cost	$ 9,072
Held to Maturity, Due after one year through five years, Amortized Cost	528,192
Held to Maturity, Due after five years through ten years, Amortized Cost	62,934
Held to Maturity, Due after ten years, Amortized Cost	2,933,887
Held to Maturity, Amortized Cost	3,534,085	$ 3,619,738
Held to Maturity, Due in one year or less, Estimated Fair Value	9,067
Held to Maturity, Due after one year through five years, Estimated Fair Value	477,554
Held to Maturity, Due after five years through ten years, Estimated Fair Value	58,653
Held to Maturity, Due after ten years, Estimated Fair Value	2,815,272
Held to Maturity, Estimated Fair Value	3,360,546	3,532,044
Available for Sale, Due in one year or less, Amortized Cost	1,381,425
Available for Sale, Due after one year through five years, Amortized Cost	2,430,874
Available for Sale, Due after five years through ten years, Amortized Cost	1,015,030
Available for Sale, Due after ten years, Amortized Cost	11,731,650
Debt Securities, Available-for-sale, Amortized Cost	16,602,158	17,965,338
Available for Sale, Due in one year or less, Estimated Fair Value	1,373,388
Available for Sale, Due after one year through five years, Estimated Fair Value	2,278,099
Available for Sale, Due after five years through ten years, Estimated Fair Value	942,623
Available for Sale, Due after ten years, Estimated Fair Value	10,406,336
Debt Securities, Available-for-sale	15,043,625	16,578,371
US Treasury [Member]
Schedule of Available-for-Sale Securities [Line Items]
Available for Sale, Due in one year or less, Amortized Cost	1,096,734
Available for Sale, Due after one year through five years, Amortized Cost	2,204,591
Available for Sale, Due after five years through ten years, Amortized Cost	198,105
Available for Sale, Due after ten years, Amortized Cost	192,785
Debt Securities, Available-for-sale, Amortized Cost	3,692,215	5,212,894
Available for Sale, Due in one year or less, Estimated Fair Value	1,088,890
Available for Sale, Due after one year through five years, Estimated Fair Value	2,054,258
Available for Sale, Due after five years through ten years, Estimated Fair Value	165,031
Available for Sale, Due after ten years, Estimated Fair Value	134,141
Debt Securities, Available-for-sale	3,442,320	4,927,589
Residential Mortgage Backed Securities [Member]
Schedule of Available-for-Sale Securities [Line Items]
Held to Maturity, Due in one year or less, Amortized Cost	0
Held to Maturity, Due after one year through five years, Amortized Cost	510,490
Held to Maturity, Due after five years through ten years, Amortized Cost	11,244
Held to Maturity, Due after ten years, Amortized Cost	672,106
Held to Maturity, Amortized Cost	1,193,840	1,250,431
Held to Maturity, Due in one year or less, Estimated Fair Value	0
Held to Maturity, Due after one year through five years, Estimated Fair Value	459,859
Held to Maturity, Due after five years through ten years, Estimated Fair Value	9,164
Held to Maturity, Due after ten years, Estimated Fair Value	653,741
Held to Maturity, Estimated Fair Value	1,122,764	1,196,332
Available for Sale, Due in one year or less, Amortized Cost	39
Available for Sale, Due after one year through five years, Amortized Cost	869
Available for Sale, Due after five years through ten years, Amortized Cost	12,553
Available for Sale, Due after ten years, Amortized Cost	8,011,243
Debt Securities, Available-for-sale, Amortized Cost	8,024,704	7,463,954
Available for Sale, Due in one year or less, Estimated Fair Value	39
Available for Sale, Due after one year through five years, Estimated Fair Value	881
Available for Sale, Due after five years through ten years, Estimated Fair Value	12,588
Available for Sale, Due after ten years, Estimated Fair Value	6,984,394
Debt Securities, Available-for-sale	6,997,902	6,596,682
States and Political Subdivisions [Member]
Schedule of Available-for-Sale Securities [Line Items]
Held to Maturity, Due in one year or less, Amortized Cost	7,572
Held to Maturity, Due after one year through five years, Amortized Cost	17,702
Held to Maturity, Due after five years through ten years, Amortized Cost	51,690
Held to Maturity, Due after ten years, Amortized Cost	2,261,781
Held to Maturity, Amortized Cost	2,338,745	2,367,807
Held to Maturity, Due in one year or less, Estimated Fair Value	7,570
Held to Maturity, Due after one year through five years, Estimated Fair Value	17,695
Held to Maturity, Due after five years through ten years, Estimated Fair Value	49,489
Held to Maturity, Due after ten years, Estimated Fair Value	2,161,531
Held to Maturity, Estimated Fair Value	2,236,285	2,334,257
Available for Sale, Due in one year or less, Amortized Cost	284,652
Available for Sale, Due after one year through five years, Amortized Cost	225,414
Available for Sale, Due after five years through ten years, Amortized Cost	804,372
Available for Sale, Due after ten years, Amortized Cost	3,527,622
Debt Securities, Available-for-sale, Amortized Cost	4,842,060	5,245,721
Available for Sale, Due in one year or less, Estimated Fair Value	284,459
Available for Sale, Due after one year through five years, Estimated Fair Value	222,960
Available for Sale, Due after five years through ten years, Estimated Fair Value	765,004
Available for Sale, Due after ten years, Estimated Fair Value	3,287,801
Debt Securities, Available-for-sale	4,560,224	5,011,331
Other [Member]
Schedule of Available-for-Sale Securities [Line Items]
Held to Maturity, Due in one year or less, Amortized Cost	1,500
Held to Maturity, Due after one year through five years, Amortized Cost	0
Held to Maturity, Due after five years through ten years, Amortized Cost	0
Held to Maturity, Due after ten years, Amortized Cost	0
Held to Maturity, Amortized Cost	1,500	1,500
Held to Maturity, Due in one year or less, Estimated Fair Value	1,497
Held to Maturity, Due after one year through five years, Estimated Fair Value	0
Held to Maturity, Due after five years through ten years, Estimated Fair Value	0
Held to Maturity, Due after ten years, Estimated Fair Value	0
Held to Maturity, Estimated Fair Value	1,497	1,455
Available for Sale, Due in one year or less, Amortized Cost	0
Available for Sale, Due after one year through five years, Amortized Cost	0
Available for Sale, Due after five years through ten years, Amortized Cost	0
Available for Sale, Due after ten years, Amortized Cost	0
Debt Securities, Available-for-sale, Amortized Cost	43,179	42,769
Available for Sale, Due in one year or less, Estimated Fair Value	0
Available for Sale, Due after one year through five years, Estimated Fair Value	0
Available for Sale, Due after five years through ten years, Estimated Fair Value	0
Available for Sale, Due after ten years, Estimated Fair Value	0
Debt Securities, Available-for-sale	$ 43,179	$ 42,769

Securities (Sales of Securities

Securities (Sales of Securities Available for Sale) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Proceeds from sales	$ 123,254	$ 1,904,067	$ 0
Gross realized gains	426	5,758	0
Gross realized losses	(522)	(5,692)	0
Tax benefit (expense) related to securities gains/losses	$ 20	$ (14)	$ 0

Securities Securities - (Premiu

Securities Securities - (Premium Amortization and Discount Accretion Included in Income on Securities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Premium amortization	$ (66,257)	$ (85,506)	$ (110,997)
Discount accretion	21,044	21,613	13,597
Net (premium amortization) discount accretion	$ (45,213)	$ (63,893)	$ (97,400)

Securities (Year End Trading Ac

Securities (Year End Trading Account Securities at Estimated Fair Value) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Debt and Equity Securities, FV-NI [Line Items]
Trading account securities	$ 33,910	$ 31,717
US Treasury [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading account securities	33,910	30,265
States and Political Subdivisions [Member]
Debt and Equity Securities, FV-NI [Line Items]
Trading account securities	$ 0	$ 1,452

Securities (Net Gains and Losse

Securities (Net Gains and Losses on Trading Account Securities) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Net gain on sales transactions	$ 4,876	$ 3,843	$ 3,129
Net mark-to-market gains (losses)	(109)	(33)	(230)
Net gain on trading account securities	$ 4,767	$ 3,810	$ 2,899

Loans (Narrative) (Detail)

Loans (Narrative) (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) Grade Rate	Dec. 31, 2023 USD ($) Grade Rate	Dec. 31, 2022 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
U.S. dollar denominated loans and commitments to borrowers in Mexico	$ 0	$ 0
Commercial and industrial loans related to overdraft for correspondent bank customer	$ 14,600	13,400
Financing Receivable, Threshold Period Past Due	90 days
Loans, net of unearned discounts	$ 20,754,813	$ 18,824,251
Loans Receivable, Basis Spread on Variable Rate | Rate	(0.50%)	(1.75%)
Loan Receivable Variable Rate | Rate	8.50%	10.25%
Number of days past due for payment of interest on loans, minimum	120 days
Texas Leading Index economic condition indicator	125.9	127.2
Financing Receivable, Change in Method, Credit Loss Expense (Reversal)	$ 7,200	$ (45,000)
Prime Rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Receivable, Basis Spread on Variable Rate | Rate	(1.50%)
Additional Funding Agreement Terms
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 44,100
Contractual Interest Rate Reduction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable Modified Interest Rate After Modification | Rate	6.50%	6.74%
Contractual Interest Rate Reduction | Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable Modified Interest Rate After Modification | Rate	6%
Loans Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accrued interest receivable	$ 86,800	$ 90,800
Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of total loans	5.40%
Loans, net of unearned discounts	$ 1,128,895	$ 936,737
Weighted Average Risk Grade | Grade	5.58	6.05
Commercial and Industrial Total Energy Loans [Member] | Risk Grade One To Eight [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 1,111,319	$ 871,221
Weighted Average Risk Grade | Grade	5.51	5.73
Non Accrual Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Impaired Interest Lost On Nonaccrual Loans	$ 5,700	$ 4,000	$ 1,700
Grade 12 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
General percentage of valuation allowance in excess of principal balance, maximum	30%
Grade 13 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
General percentage of valuation allowance in excess of principal balance, minimum	30%
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 6,109,532	$ 5,967,182
Weighted Average Risk Grade | Grade	6.64	6.60
Commercial Portfolio Segment [Member] | Risk Grade One To Eight [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 5,553,757	$ 5,507,878
Weighted Average Risk Grade | Grade	6.30	6.32
Commercial and Industrial, Other Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of days past due for payment of interest on loans, minimum	180 days
Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 9,968,523	$ 8,982,644
Weighted Average Risk Grade | Grade	7.35	7.24
Commercial Real Estate Buildings Land And Other Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 7,704,447	$ 7,301,920
Weighted Average Risk Grade | Grade	7.25	7.20
Commercial Real Estate Buildings Land And Other Financing Receivable [Member] | Risk Grade One To Eight [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 7,103,502	$ 6,895,358
Weighted Average Risk Grade | Grade	7.01	7.03
Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 2,264,076	$ 1,680,724
Weighted Average Risk Grade | Grade	7.71	7.45
Construction Loans [Member] | Risk Grade One To Eight [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 1,860,004	$ 1,526,086
Weighted Average Risk Grade | Grade	7.31	7.27
Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 444,474	$ 476,962
Financing Receivable, Change in Method, Credit Loss Expense (Reversal)	923
Bank Overdrafts | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Nonperforming Financial Instruments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	24,200
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	$ 5,500
Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of total loans	6%
Commercial mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 7,165,220	$ 6,746,709
Financing Receivable, Change in Method, Credit Loss Expense (Reversal)	6,200
Commitments to Extend Credit [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unfunded balances	1,000,000
Commitments to Extend Credit [Member] | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unfunded balances	535,500
Standby Letters of Credit [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unfunded balances	62,800
Standby Letters of Credit [Member] | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unfunded balances	$ 20,200

Loans (Loans) (Detail)

Loans (Loans) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 20,754,813	$ 18,824,251
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	6,109,532	5,967,182
Energy Production [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	903,654	681,568
Energy Service [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	203,629	194,126
Energy Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	21,612	61,043
Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	1,128,895	936,737
Commercial mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	7,165,220	6,746,709
Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	2,264,076	1,680,724
Commercial land loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	539,227	555,211
Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	9,968,523	8,982,644
Home Equity Line of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	911,239	792,876
Home Equity Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	914,738	694,966
Home Improvement Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	852,536	765,887
Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	259,456	38,923
Other consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	165,420	168,074
Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	3,103,389	2,460,726
Real Estate Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	13,071,912	11,443,370
Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 444,474	$ 476,962

Loans (Activities in Related Pa

Loans (Activities in Related Party Loans) (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($)
Receivables [Abstract]
Beginning balance	$ 416,107
Principal additions	306,414
Principal payments	(296,754)
Other changes	(129,931)
Ending balance	$ 295,836

Loans (Non-Accrual Loans, Segre

Loans (Non-Accrual Loans, Segregated by Class of Loans) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	$ 78,866	$ 60,907
Financing Receivable, Nonaccrual, No Allowance	32,885	22,932
Commercial Portfolio Segment [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	46,004	19,545
Financing Receivable, Nonaccrual, No Allowance	8,800	5,391
Commercial and Industrial Total Energy Loans [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	4,079	11,500
Financing Receivable, Nonaccrual, No Allowance	1,377	7,398
Commercial Real Estate, Buildings, Land and Other [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	21,920	22,420
Financing Receivable, Nonaccrual, No Allowance	18,660	4,983
Construction Loans [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	0	0
Financing Receivable, Nonaccrual, No Allowance	0	0
Total consumer real estate loans [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	6,511	7,442
Financing Receivable, Nonaccrual, No Allowance	4,048	5,160
Consumer Loan [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	352	0
Financing Receivable, Nonaccrual, No Allowance	$ 0	$ 0

Loans (Non-Accrual Loans, Seg_2

Loans (Non-Accrual Loans, Segregated by Class of Loan and Year of Origination) (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Loans and Leases Receivable Disclosure [Line Items]
Financing Receivable, Nonaccrual	$ 78,866	$ 60,907
Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,630,146	1,619,306
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	567,373	768,246
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	508,217	499,987
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	289,789	364,446
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	308,636	182,089
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	279,503	219,766
Financing Receivable, Excluding Accrued Interest, Revolving	2,413,231	2,247,752
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	112,637	65,590
Financing Receivable, Nonaccrual	46,004	19,545
Commercial and Industrial Total Energy Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	388,092	277,722
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	24,187	61,500
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	38,109	76,103
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	18,161	3,835
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	1,608	6,876
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	4,367	4,541
Financing Receivable, Excluding Accrued Interest, Revolving	647,099	495,329
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	7,272	10,831
Financing Receivable, Nonaccrual	4,079	11,500
Commercial Real Estate, Buildings, Land and Other [Member]
Loans and Leases Receivable Disclosure [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,450,749	1,645,223
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,347,348	1,785,624
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,638,136	1,253,062
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	1,160,877	811,574
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	704,334	522,566
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,095,642	953,768
Financing Receivable, Excluding Accrued Interest, Revolving	209,545	229,733
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	97,816	100,370
Financing Receivable, Nonaccrual	21,920	22,420
Construction Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	769,805	560,720
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	610,434	576,374
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	541,575	344,641
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	171,695	28,063
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	2,727	296
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	559	1,613
Financing Receivable, Excluding Accrued Interest, Revolving	167,122	169,017
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	159	0
Financing Receivable, Nonaccrual	0	0
Total consumer real estate loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Financing Receivable, Nonaccrual	6,511	7,442
Consumer Loan [Member]
Loans and Leases Receivable Disclosure [Line Items]
Financing Receivable, Nonaccrual	352	0
Nonperforming Financial Instruments [Member]
Loans and Leases Receivable Disclosure [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	28,675	25,974
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	5,985	359
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	7,286	1,785
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	4,345	1,079
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	1,731	6,310
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	7,172	2,209
Financing Receivable, Excluding Accrued Interest, Revolving	4,475	5,711
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	19,197	17,480
Nonperforming Financial Instruments [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	20,819	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,915	359
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	4,053	1,635
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	1,592	985
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	335	1,257
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	2,144	1,006
Financing Receivable, Excluding Accrued Interest, Revolving	1,186	9
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	12,960	14,294
Nonperforming Financial Instruments [Member] | Commercial and Industrial Total Energy Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	5,875
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	56
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	56	1,321
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,321	0
Financing Receivable, Excluding Accrued Interest, Revolving	2,702	4,102
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0	146
Nonperforming Financial Instruments [Member] | Commercial Real Estate, Buildings, Land and Other [Member]
Loans and Leases Receivable Disclosure [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	7,856	20,099
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,671	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	3,233	150
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	2,753	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	1,248	1,451
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,505	720
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	2,654	0
Nonperforming Financial Instruments [Member] | Construction Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0	0
Nonperforming Financial Instruments [Member] | Total consumer real estate loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	47	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	38
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	92	2,281
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	2,202	483
Financing Receivable, Excluding Accrued Interest, Revolving	587	1,600
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	3,583	3,040
Nonperforming Financial Instruments [Member] | Consumer Loan [Member]
Loans and Leases Receivable Disclosure [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	352	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	$ 0	$ 0

Loans (Age Analysis of Past Due

Loans (Age Analysis of Past Due Loans, Segregated by Class of Loans) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	$ 20,754,813	$ 18,824,251
Financing Receivable, Excluding Accrued Interest, 90 Days or More Past Due, Still Accruing	15,711
Commercial Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	6,109,532	5,967,182
Financing Receivable, Excluding Accrued Interest, 90 Days or More Past Due, Still Accruing	7,685
Commercial and Industrial Total Energy Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	1,128,895	936,737
Financing Receivable, Excluding Accrued Interest, 90 Days or More Past Due, Still Accruing	0
Commercial Real Estate, Buildings, Land and Other [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	7,704,447	7,301,920
Financing Receivable, Excluding Accrued Interest, 90 Days or More Past Due, Still Accruing	1,523
Construction Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	2,264,076	1,680,724
Financing Receivable, Excluding Accrued Interest, 90 Days or More Past Due, Still Accruing	0
Total consumer real estate loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	3,103,389	2,460,726
Financing Receivable, Excluding Accrued Interest, 90 Days or More Past Due, Still Accruing	5,681
Consumer Loan [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	444,474	476,962
Financing Receivable, Excluding Accrued Interest, 90 Days or More Past Due, Still Accruing	822
Financing Receivables, 30 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	103,496
Financing Receivables, 30 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	37,130
Financing Receivables, 30 to 89 Days Past Due [Member] | Commercial and Industrial Total Energy Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	4,263
Financing Receivables, 30 to 89 Days Past Due [Member] | Commercial Real Estate, Buildings, Land and Other [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	37,525
Financing Receivables, 30 to 89 Days Past Due [Member] | Construction Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	870
Financing Receivables, 30 to 89 Days Past Due [Member] | Total consumer real estate loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	17,015	12,504
Financing Receivables, 30 to 89 Days Past Due [Member] | Consumer Loan [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	6,693	6,495
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	58,089
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	28,120
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial and Industrial Total Energy Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	4,079
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Real Estate, Buildings, Land and Other [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	13,040
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Construction Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Total consumer real estate loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	12,028	7,716
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Loan [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	822	251
Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	161,585
Financial Asset, Past Due | Commercial Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	65,250
Financial Asset, Past Due | Commercial and Industrial Total Energy Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	8,342
Financial Asset, Past Due | Commercial Real Estate, Buildings, Land and Other [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	50,565
Financial Asset, Past Due | Construction Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	870
Financial Asset, Past Due | Total consumer real estate loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	29,043	20,220
Financial Asset, Past Due | Consumer Loan [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	7,515	6,746
Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	20,593,228
Financial Asset, Not Past Due | Commercial Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	6,044,282
Financial Asset, Not Past Due | Commercial and Industrial Total Energy Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	1,120,553
Financial Asset, Not Past Due | Commercial Real Estate, Buildings, Land and Other [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	7,653,882
Financial Asset, Not Past Due | Construction Loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	2,263,206
Financial Asset, Not Past Due | Total consumer real estate loans [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	3,074,346	2,440,506
Financial Asset, Not Past Due | Consumer Loan [Member]
Financing Receivable, Past Due [Line Items]
Loans, net of unearned discounts	$ 436,959	$ 470,216

Loans (Modification to Borrower

Loans (Modification to Borrowers Experiencing Financial Difficulty) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 20,754,813	$ 18,824,251
Payment Deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 8,138	$ 0
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0%	0%
Combination: Payment Delay and Term Extention
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 45,835	$ 33,251
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.20%	0.20%
Extended Maturity and Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 31,302	$ 2,092
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.20%	0%
Commercial Portfolio Segment [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 6,109,532	$ 5,967,182
Commercial Portfolio Segment [Member] | Payment Deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 6,126	$ 0
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.10%	0%
Commercial Portfolio Segment [Member] | Combination: Payment Delay and Term Extention
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 45,835	$ 13,813
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.80%	0.20%
Commercial Portfolio Segment [Member] | Extended Maturity and Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 0	$ 0
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0%	0%
Commercial Real Estate, Buildings, Land and Other [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 7,704,447	$ 7,301,920
Commercial Real Estate, Buildings, Land and Other [Member] | Payment Deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 2,012	$ 0
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0%	0%
Commercial Real Estate, Buildings, Land and Other [Member] | Combination: Payment Delay and Term Extention
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 0	$ 19,438
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0%	0.30%
Commercial Real Estate, Buildings, Land and Other [Member] | Extended Maturity and Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 31,302	$ 2,092
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.40%	0%

Loans (Modified Loans by Type o

Loans (Modified Loans by Type of Modification) (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 20,754,813	$ 18,824,251
Payment Deferral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	8,138	0
Combination: Payment Delay and Term Extention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	45,835	33,251
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	58,089
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Payment Deferral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	3,705	0	$ 1,051
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Combination: Payment Delay and Term Extention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	0	33,251	0
Charge-offs | Payment Deferral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts			371
Charge-offs | Combination: Payment Delay and Term Extention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts			352
Proceeds from sales | Payment Deferral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts			0
Proceeds from sales | Combination: Payment Delay and Term Extention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts			1,070
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	6,109,532	5,967,182
Commercial Portfolio Segment [Member] | Payment Deferral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	6,126	0
Commercial Portfolio Segment [Member] | Combination: Payment Delay and Term Extention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	45,835	13,813
Commercial Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	28,120
Commercial Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Payment Deferral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	1,693	0
Commercial Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Combination: Payment Delay and Term Extention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	0	13,813
Commercial Real Estate, Buildings, Land and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	7,704,447	7,301,920
Commercial Real Estate, Buildings, Land and Other [Member] | Payment Deferral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	2,012	0
Commercial Real Estate, Buildings, Land and Other [Member] | Combination: Payment Delay and Term Extention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	0	19,438
Commercial Real Estate, Buildings, Land and Other [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	13,040
Commercial Real Estate, Buildings, Land and Other [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Payment Deferral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	2,012	0	1,051
Commercial Real Estate, Buildings, Land and Other [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Combination: Payment Delay and Term Extention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 0	$ 19,438	0
Commercial Real Estate, Buildings, Land and Other [Member] | Charge-offs | Payment Deferral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts			371
Commercial Real Estate, Buildings, Land and Other [Member] | Charge-offs | Combination: Payment Delay and Term Extention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts			352
Commercial Real Estate, Buildings, Land and Other [Member] | Proceeds from sales | Payment Deferral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts			0
Commercial Real Estate, Buildings, Land and Other [Member] | Proceeds from sales | Combination: Payment Delay and Term Extention
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts			$ 1,070

Loans (Weighted Average Risk Gr

Loans (Weighted Average Risk Grades for All Commercial Loans by Class) (Detail) $ in Thousands	Dec. 31, 2024 USD ($) Grade	Dec. 31, 2023 USD ($) Grade
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 20,754,813	$ 18,824,251
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,630,146	1,619,306
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	567,373	768,246
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	508,217	499,987
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	289,789	364,446
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	308,636	182,089
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	279,503	219,766
Financing Receivable, Excluding Accrued Interest, Revolving	2,413,231	2,247,752
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	112,637	65,590
Loans, net of unearned discounts	$ 6,109,532	$ 5,967,182
Weighted Average Risk Grade | Grade	6.64	6.60
Commercial Portfolio Segment [Member] | Revolving Credit Facility
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	6.30	6.50
Commercial Portfolio Segment [Member] | Revolving Loans Converted to Term
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	9.12	8.48
Commercial Portfolio Segment [Member] | 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	6.73
Commercial Portfolio Segment [Member] | 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.12	6.53
Commercial Portfolio Segment [Member] | 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.52	7.05
Commercial Portfolio Segment [Member] | 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.13	7.26
Commercial Portfolio Segment [Member] | 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	5.58	5.87
Commercial Portfolio Segment [Member] | 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade		6.01
Commercial Portfolio Segment [Member] | Prior Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	6.11	6.04
Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	$ 388,092	$ 277,722
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	24,187	61,500
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	38,109	76,103
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	18,161	3,835
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	1,608	6,876
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	4,367	4,541
Financing Receivable, Excluding Accrued Interest, Revolving	647,099	495,329
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	7,272	10,831
Loans, net of unearned discounts	$ 1,128,895	$ 936,737
Weighted Average Risk Grade | Grade	5.58	6.05
Commercial and Industrial Total Energy Loans [Member] | Revolving Credit Facility
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	5.05	5.75
Commercial and Industrial Total Energy Loans [Member] | Revolving Loans Converted to Term
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.31	7.33
Commercial and Industrial Total Energy Loans [Member] | 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	6.16
Commercial and Industrial Total Energy Loans [Member] | 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.14	6.19
Commercial and Industrial Total Energy Loans [Member] | 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.53	7.07
Commercial and Industrial Total Energy Loans [Member] | 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	4.75	6
Commercial and Industrial Total Energy Loans [Member] | 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	6.47	6.99
Commercial and Industrial Total Energy Loans [Member] | 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade		10.02
Commercial and Industrial Total Energy Loans [Member] | Prior Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	8.97	7.07
Commercial Real Estate, Buildings, Land and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	$ 1,450,749	$ 1,645,223
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,347,348	1,785,624
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,638,136	1,253,062
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	1,160,877	811,574
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	704,334	522,566
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,095,642	953,768
Financing Receivable, Excluding Accrued Interest, Revolving	209,545	229,733
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	97,816	100,370
Loans, net of unearned discounts	$ 7,704,447	$ 7,301,920
Weighted Average Risk Grade | Grade	7.25	7.20
Commercial Real Estate, Buildings, Land and Other [Member] | Revolving Credit Facility
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	6.01	7.49
Commercial Real Estate, Buildings, Land and Other [Member] | Revolving Loans Converted to Term
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	6.80	6.77
Commercial Real Estate, Buildings, Land and Other [Member] | 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.16
Commercial Real Estate, Buildings, Land and Other [Member] | 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.32	7.23
Commercial Real Estate, Buildings, Land and Other [Member] | 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.39	7.18
Commercial Real Estate, Buildings, Land and Other [Member] | 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.52	7.29
Commercial Real Estate, Buildings, Land and Other [Member] | 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.05	7.22
Commercial Real Estate, Buildings, Land and Other [Member] | 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade		6.90
Commercial Real Estate, Buildings, Land and Other [Member] | Prior Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.17	7.16
Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	$ 769,805	$ 560,720
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	610,434	576,374
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	541,575	344,641
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	171,695	28,063
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	2,727	296
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	559	1,613
Financing Receivable, Excluding Accrued Interest, Revolving	167,122	169,017
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	159	0
Loans, net of unearned discounts	$ 2,264,076	$ 1,680,724
Weighted Average Risk Grade | Grade	7.71	7.45
Construction Loans [Member] | Revolving Credit Facility
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	6.46	7.34
Construction Loans [Member] | Revolving Loans Converted to Term
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	6.98	0
Construction Loans [Member] | 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.82
Construction Loans [Member] | 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.35	7.44
Construction Loans [Member] | 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.99	7.44
Construction Loans [Member] | 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	8.85	7.93
Construction Loans [Member] | 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.39	2.55
Construction Loans [Member] | 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade		7.22
Construction Loans [Member] | Prior Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.65	6.78
Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	$ 2,220,554	$ 2,205,943
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,957,782	2,361,998
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	2,179,711	1,597,703
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	1,332,572	839,637
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	707,061	522,862
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,096,201	955,381
Financing Receivable, Excluding Accrued Interest, Revolving	376,667	398,750
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	97,975	100,370
Loans, net of unearned discounts	$ 9,968,523	$ 8,982,644
Weighted Average Risk Grade | Grade	7.35	7.24
Commercial Real Estate Portfolio Segment [Member] | Revolving Credit Facility
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	6.21	7.43
Commercial Real Estate Portfolio Segment [Member] | Revolving Loans Converted to Term
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	6.80	6.77
Commercial Real Estate Portfolio Segment [Member] | 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.39
Commercial Real Estate Portfolio Segment [Member] | 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.33	7.28
Commercial Real Estate Portfolio Segment [Member] | 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.54	7.24
Commercial Real Estate Portfolio Segment [Member] | 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.69	7.43
Commercial Real Estate Portfolio Segment [Member] | 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.06	7.07
Commercial Real Estate Portfolio Segment [Member] | 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade		6.90
Commercial Real Estate Portfolio Segment [Member] | Prior Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Grade | Grade	7.17	7.15
Risk Grade One To Eight [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	$ 1,553,200	$ 1,489,026
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	513,073	706,210
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	385,824	458,855
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	257,280	349,744
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	298,912	172,656
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	253,018	206,643
Financing Receivable, Excluding Accrued Interest, Revolving	2,242,193	2,083,490
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	50,257	41,254
Loans, net of unearned discounts	$ 5,553,757	$ 5,507,878
Weighted Average Risk Grade | Grade	6.30	6.32
Risk Grade One To Eight [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	$ 387,904	$ 270,710
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	22,510	54,185
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	35,357	75,004
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	16,150	3,673
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	1,516	1,819
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	2,648	4,047
Financing Receivable, Excluding Accrued Interest, Revolving	639,362	451,897
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	5,872	9,886
Loans, net of unearned discounts	$ 1,111,319	$ 871,221
Weighted Average Risk Grade | Grade	5.51	5.73
Risk Grade One To Eight [Member] | Commercial Real Estate, Buildings, Land and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	$ 1,427,212	$ 1,601,175
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,288,934	1,667,750
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,450,649	1,186,559
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	1,006,922	747,289
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	668,316	503,303
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	965,448	874,942
Financing Receivable, Excluding Accrued Interest, Revolving	204,577	214,874
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	91,444	99,466
Loans, net of unearned discounts	$ 7,103,502	$ 6,895,358
Weighted Average Risk Grade | Grade	7.01	7.03
Risk Grade One To Eight [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	$ 615,683	$ 538,072
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	601,151	537,705
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	427,984	264,770
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	59,895	28,063
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	2,727	296
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	559	1,613
Financing Receivable, Excluding Accrued Interest, Revolving	151,846	155,567
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	159	0
Loans, net of unearned discounts	$ 1,860,004	$ 1,526,086
Weighted Average Risk Grade | Grade	7.31	7.27
Risk Grade Nine [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	$ 15,552	$ 57,625
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	24,059	42,618
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	58,521	12,258
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	25,818	4,952
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	3,796	1,641
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	9,959	10,383
Financing Receivable, Excluding Accrued Interest, Revolving	109,594	70,142
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	15,147	5,625
Loans, net of unearned discounts	262,446	205,244
Risk Grade Nine [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	1,137
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,677	7,315
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	662	1,041
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	2,011	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0	456
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	398	0
Financing Receivable, Excluding Accrued Interest, Revolving	5,035	17,680
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	1,400	14
Loans, net of unearned discounts	11,183	27,643
Risk Grade Nine [Member] | Commercial Real Estate, Buildings, Land and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	9,347	12,173
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	18,408	68,007
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	56,419	28,870
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	72,096	13,250
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	11,197	16,272
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	35,661	23,214
Financing Receivable, Excluding Accrued Interest, Revolving	4,968	11,143
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	3,718	541
Loans, net of unearned discounts	211,814	173,470
Risk Grade Nine [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	46,456	3,414
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	9,283	35,565
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	65,590	79,871
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	35,006	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Revolving	15,276	8,252
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0	0
Loans, net of unearned discounts	171,611	127,102
Risk Grade Ten [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	4,992	63,205
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	9,269	2,222
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	42,146	1,307
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	2,112	911
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	918	4,005
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	12,290	581
Financing Receivable, Excluding Accrued Interest, Revolving	15,332	35,977
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	1,876	1,046
Loans, net of unearned discounts	88,935	109,254
Risk Grade Ten [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	52	33
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0	291
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	494
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0	0
Loans, net of unearned discounts	52	818
Risk Grade Ten [Member] | Commercial Real Estate, Buildings, Land and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	570	7,671
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	31,596	29,278
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	64,063	17,364
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	55,512	34,672
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	10,546	747
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	10,746	3,153
Financing Receivable, Excluding Accrued Interest, Revolving	0	3,716
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0	0
Loans, net of unearned discounts	173,033	96,601
Risk Grade Ten [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	107,666	13,322
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	48,001	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	76,794	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Revolving	0	3,713
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0	0
Loans, net of unearned discounts	232,461	17,035
Risk Grade Eleven [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	35,583	9,450
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	18,057	16,837
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	17,673	25,932
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	2,987	7,854
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	4,675	2,530
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	2,092	1,153
Financing Receivable, Excluding Accrued Interest, Revolving	44,926	58,134
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	32,397	3,371
Loans, net of unearned discounts	158,390	125,261
Risk Grade Eleven [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	188	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	2,038	25
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	106
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	36	2,989
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Revolving	0	21,650
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0	785
Loans, net of unearned discounts	2,262	25,555
Risk Grade Eleven [Member] | Commercial Real Estate, Buildings, Land and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	5,764	4,105
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	5,739	20,589
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	63,772	20,119
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	23,594	16,363
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	13,027	793
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	82,282	51,739
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0	363
Loans, net of unearned discounts	194,178	114,071
Risk Grade Eleven [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	5,912
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	3,104
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Revolving	0	1,485
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0	0
Loans, net of unearned discounts	0	10,501
Risk Grade Twelve [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	13,107	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,443	359
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	2,574	1,635
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	1,564	950
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	324	1,257
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	2,144	1,006
Financing Receivable, Excluding Accrued Interest, Revolving	1,179	1
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	9,404	11,894
Loans, net of unearned discounts	32,739	17,102
Risk Grade Twelve [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	5,875
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	56
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	56	1,321
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,321	0
Financing Receivable, Excluding Accrued Interest, Revolving	2	1,402
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0	146
Loans, net of unearned discounts	1,379	8,800
Risk Grade Twelve [Member] | Commercial Real Estate, Buildings, Land and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	7,856	17,449
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,671	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	3,233	150
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	2,531	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	1,126	1,451
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,505	720
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	2,373	0
Loans, net of unearned discounts	21,295	19,770
Risk Grade Twelve [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0	0
Loans, net of unearned discounts	0	0
Risk Grade Thirteen [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	7,712	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	472	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,479	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	28	35
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	11	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Revolving	7	8
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	3,556	2,400
Loans, net of unearned discounts	13,265	2,443
Risk Grade Thirteen [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Revolving	2,700	2,700
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0	0
Loans, net of unearned discounts	2,700	2,700
Risk Grade Thirteen [Member] | Commercial Real Estate, Buildings, Land and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	2,650
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	222	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	122	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	281	0
Loans, net of unearned discounts	625	2,650
Risk Grade Thirteen [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0	0
Loans, net of unearned discounts	$ 0	$ 0

Loans (Age Analysis of Past D_2

Loans (Age Analysis of Past Due Consumer Loans, Segregated By Class and Year of Origination) (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 20,754,813	$ 18,824,251
Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	103,496
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	58,089
Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	161,585
Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	20,593,228
Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	3,103,389	2,460,726
Total consumer real estate loans [Member] | Revolving Credit Facility
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	899,090	781,601
Total consumer real estate loans [Member] | Revolving Loans Converted to Term
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	12,224	11,335
Total consumer real estate loans [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	17,015	12,504
Total consumer real estate loans [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Revolving Credit Facility
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	9,790	3,570
Total consumer real estate loans [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Revolving Loans Converted to Term
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	112	539
Total consumer real estate loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	12,028	7,716
Total consumer real estate loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Revolving Credit Facility
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	2,452	2,566
Total consumer real estate loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Revolving Loans Converted to Term
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	3,679	3,087
Total consumer real estate loans [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	29,043	20,220
Total consumer real estate loans [Member] | Financial Asset, Past Due | Revolving Credit Facility
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	12,242	6,136
Total consumer real estate loans [Member] | Financial Asset, Past Due | Revolving Loans Converted to Term
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	3,791	3,626
Total consumer real estate loans [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	3,074,346	2,440,506
Total consumer real estate loans [Member] | Financial Asset, Not Past Due | Revolving Credit Facility
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	886,848	775,465
Total consumer real estate loans [Member] | Financial Asset, Not Past Due | Revolving Loans Converted to Term
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	8,433	7,709
Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	444,474	476,962
Consumer Loan [Member] | Revolving Credit Facility
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	317,167	342,393
Consumer Loan [Member] | Revolving Loans Converted to Term
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	25,094	22,128
Consumer Loan [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	6,693	6,495
Consumer Loan [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Revolving Credit Facility
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	1,734	2,553
Consumer Loan [Member] | Financing Receivables, 30 to 89 Days Past Due [Member] | Revolving Loans Converted to Term
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	449	158
Consumer Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	822	251
Consumer Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Revolving Credit Facility
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	395	51
Consumer Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Revolving Loans Converted to Term
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	181	0
Consumer Loan [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	7,515	6,746
Consumer Loan [Member] | Financial Asset, Past Due | Revolving Credit Facility
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	2,129	2,604
Consumer Loan [Member] | Financial Asset, Past Due | Revolving Loans Converted to Term
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	630	158
Consumer Loan [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	436,959	470,216
Consumer Loan [Member] | Financial Asset, Not Past Due | Revolving Credit Facility
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	315,038	339,789
Consumer Loan [Member] | Financial Asset, Not Past Due | Revolving Loans Converted to Term
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	24,464	21,970
2024 | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	699,828
2024 | Total consumer real estate loans [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	632
2024 | Total consumer real estate loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	0
2024 | Total consumer real estate loans [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	632
2024 | Total consumer real estate loans [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	699,196
2024 | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	58,061
2024 | Consumer Loan [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	3,378
2024 | Consumer Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	243
2024 | Consumer Loan [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	3,621
2024 | Consumer Loan [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	54,440
2023 | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	546,133	580,379
2023 | Total consumer real estate loans [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	1,030	874
2023 | Total consumer real estate loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	292	0
2023 | Total consumer real estate loans [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	1,322	874
2023 | Total consumer real estate loans [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	544,811	579,505
2023 | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	28,477	70,439
2023 | Consumer Loan [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	772	3,014
2023 | Consumer Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	0	153
2023 | Consumer Loan [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	772	3,167
2023 | Consumer Loan [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	27,705	67,272
2022 | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	390,213	435,297
2022 | Total consumer real estate loans [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	1,897	2,066
2022 | Total consumer real estate loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	972	512
2022 | Total consumer real estate loans [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	2,869	2,578
2022 | Total consumer real estate loans [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	387,344	432,719
2022 | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	9,525	29,373
2022 | Consumer Loan [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	249	488
2022 | Consumer Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	0	0
2022 | Consumer Loan [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	249	488
2022 | Consumer Loan [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	9,276	28,885
2021 | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	250,355	283,764
2021 | Total consumer real estate loans [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	965	1,318
2021 | Total consumer real estate loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	1,165	626
2021 | Total consumer real estate loans [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	2,130	1,944
2021 | Total consumer real estate loans [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	248,225	281,820
2021 | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	3,028	6,465
2021 | Consumer Loan [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	22	148
2021 | Consumer Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	0	27
2021 | Consumer Loan [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	22	175
2021 | Consumer Loan [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	3,006	6,290
2020 | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	147,830	171,222
2020 | Total consumer real estate loans [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	645	959
2020 | Total consumer real estate loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	213	38
2020 | Total consumer real estate loans [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	858	997
2020 | Total consumer real estate loans [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	146,972	170,225
2020 | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	1,972	3,647
2020 | Consumer Loan [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	66	66
2020 | Consumer Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	0	0
2020 | Consumer Loan [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	66	66
2020 | Consumer Loan [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	1,906	3,581
2019 | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts		59,281
2019 | Total consumer real estate loans [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts		537
2019 | Total consumer real estate loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts		0
2019 | Total consumer real estate loans [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts		537
2019 | Total consumer real estate loans [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts		58,744
2019 | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts		1,247
2019 | Consumer Loan [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts		28
2019 | Consumer Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts		20
2019 | Consumer Loan [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts		48
2019 | Consumer Loan [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts		1,199
Prior Years | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	157,716	137,847
Prior Years | Total consumer real estate loans [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	1,944	2,641
Prior Years | Total consumer real estate loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	3,255	887
Prior Years | Total consumer real estate loans [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	5,199	3,528
Prior Years | Total consumer real estate loans [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	152,517	134,319
Prior Years | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	1,150	1,270
Prior Years | Consumer Loan [Member] | Financing Receivables, 30 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	23	40
Prior Years | Consumer Loan [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	3	0
Prior Years | Consumer Loan [Member] | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	26	40
Prior Years | Consumer Loan [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 1,124	$ 1,230

Loans (Revolving Loans Converte

Loans (Revolving Loans Converted to Term) (Details) - Revolving Loans Converted to Term - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan During Period	$ 98,186	$ 49,851
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan During Period	71,275	28,713
Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan During Period	2,393	6,409
Commercial Real Estate, Buildings, Land and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan During Period	9,776	4,780
Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan During Period	159	0
Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan During Period	3,425	2,467
Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan During Period	$ 11,158	$ 7,482

Loans (Allowance for Credit Los

Loans (Allowance for Credit Loss By Loan Class Calculated in Accordance With CECL Methodology) (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	$ 270,151	$ 245,996
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	87,569	74,006	$ 104,237	$ 72,091
Commercial and Industrial Total Energy Loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	9,992	17,814	18,062	17,217
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	143,205	130,598	90,301	144,936
Total consumer real estate loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	19,106	13,538	8,004	6,585
Consumer Loan [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	10,279	10,040	7,017	7,837
Loans Receivable [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	270,151	245,996	$ 227,621	$ 248,666
Modeled Expected Credit Losses [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	97,926	92,573
Modeled Expected Credit Losses [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	51,669	50,959
Modeled Expected Credit Losses [Member] | Commercial and Industrial Total Energy Loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	3,969	7,838
Modeled Expected Credit Losses [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	17,549	15,443
Modeled Expected Credit Losses [Member] | Total consumer real estate loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	17,720	12,364
Modeled Expected Credit Losses [Member] | Consumer Loan [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	7,019	5,969
Q-factor adjustments [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	154,704	144,897
Q-factor adjustments [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	22,635	20,612
Q-factor adjustments [Member] | Commercial and Industrial Total Energy Loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	3,323	7,276
Q-factor adjustments [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	125,031	112,505
Q-factor adjustments [Member] | Total consumer real estate loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	620	433
Q-factor adjustments [Member] | Consumer Loan [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	3,095	4,071
Specific Valuation Allowances [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	17,521	8,526
Specific Valuation Allowances [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	13,265	2,435
Specific Valuation Allowances [Member] | Commercial and Industrial Total Energy Loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	2,700	2,700
Specific Valuation Allowances [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	625	2,650
Specific Valuation Allowances [Member] | Total consumer real estate loans [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	766	741
Specific Valuation Allowances [Member] | Consumer Loan [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	$ 165	$ 0

Loans (Activity in Allowance fo

Loans (Activity in Allowance for Loan Losses by Portfolio Segment) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance	$ 245,996
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance	270,151	$ 245,996
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance	74,006	104,237	$ 72,091
Financing Receivable, Excluding Accrued Interest, Credit Loss Expense (Reversal)	24,494	(16,709)	34,479
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff	(14,828)	(18,315)	(6,575)
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Recovery	3,897	4,793	4,242
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Write-offs, Net	(10,931)	(13,522)	(2,333)
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance	87,569	74,006	104,237
Commercial And Industrial Energy Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance	17,814	18,062	17,217
Financing Receivable, Excluding Accrued Interest, Credit Loss Expense (Reversal)	(8,977)	(1,067)	(313)
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff	(79)	(518)	(371)
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Recovery	1,234	1,337	1,529
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Write-offs, Net	1,155	819	1,158
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance	9,992	17,814	18,062
Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance	130,598	90,301	144,936
Financing Receivable, Excluding Accrued Interest, Credit Loss Expense (Reversal)	16,479	40,889	(54,775)
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff	(3,919)	(955)	(702)
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Recovery	47	363	842
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Write-offs, Net	(3,872)	(592)	140
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance	143,205	130,598	90,301
Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance	13,538	8,004	6,585
Financing Receivable, Excluding Accrued Interest, Credit Loss Expense (Reversal)	9,753	6,736	1,813
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff	(4,940)	(2,883)	(912)
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Recovery	755	1,681	518
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Write-offs, Net	(4,185)	(1,202)	(394)
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance	19,106	13,538	8,004
Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance	10,040	7,017	7,837
Financing Receivable, Excluding Accrued Interest, Credit Loss Expense (Reversal)	23,083	23,012	13,517
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff	(33,344)	(31,260)	(24,388)
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Recovery	10,500	11,271	10,051
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Write-offs, Net	(22,844)	(19,989)	(14,337)
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance	10,279	10,040	7,017
Loans Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Beginning Balance	245,996	227,621	248,666
Financing Receivable, Excluding Accrued Interest, Credit Loss Expense (Reversal)	64,832	52,861	(5,279)
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff	(57,110)	(53,931)	(32,948)
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Recovery	16,433	19,445	17,182
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Write-offs, Net	(40,677)	(34,486)	(15,766)
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest, Ending Balance	$ 270,151	$ 245,996	$ 227,621

Loans (Gross Charge-Offs By Yea

Loans (Gross Charge-Offs By Year of Origination) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Nonperforming Financial Instruments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	$ 28,675	$ 25,974
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	5,985	359
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	7,286	1,785
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	4,345	1,079
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	1,731	6,310
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	7,172	2,209
Financing Receivable, Excluding Accrued Interest, Revolving	4,475	5,711
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	19,197	17,480
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Nonperforming Financial Instruments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	25,908
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	12,026
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,459
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	796
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	433
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,400
Financing Receivable, Excluding Accrued Interest, Revolving	11,796
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	3,292
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,630,146	1,619,306
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	567,373	768,246
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	508,217	499,987
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	289,789	364,446
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	308,636	182,089
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	279,503	219,766
Financing Receivable, Excluding Accrued Interest, Revolving	2,413,231	2,247,752
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	112,637	65,590
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff	14,828	18,315	$ 6,575
Commercial Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	20,819	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,915	359
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	4,053	1,635
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	1,592	985
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	335	1,257
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	2,144	1,006
Financing Receivable, Excluding Accrued Interest, Revolving	1,186	9
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	12,960	14,294
Commercial Portfolio Segment [Member] | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Nonperforming Financial Instruments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,423
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,820
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	804
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	487
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	403
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	625
Financing Receivable, Excluding Accrued Interest, Revolving	6,273
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	2,993
Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	388,092	277,722
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	24,187	61,500
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	38,109	76,103
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	18,161	3,835
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	1,608	6,876
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	4,367	4,541
Financing Receivable, Excluding Accrued Interest, Revolving	647,099	495,329
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	7,272	10,831
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff	79	518	371
Commercial and Industrial Total Energy Loans [Member] | Nonperforming Financial Instruments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	5,875
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	56
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	56	1,321
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,321	0
Financing Receivable, Excluding Accrued Interest, Revolving	2,702	4,102
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0	146
Commercial and Industrial Total Energy Loans [Member] | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Nonperforming Financial Instruments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	79
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	0
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Commercial Real Estate, Buildings, Land and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	1,450,749	1,645,223
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,347,348	1,785,624
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	1,638,136	1,253,062
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	1,160,877	811,574
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	704,334	522,566
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,095,642	953,768
Financing Receivable, Excluding Accrued Interest, Revolving	209,545	229,733
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	97,816	100,370
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff	3,919
Commercial Real Estate, Buildings, Land and Other [Member] | Nonperforming Financial Instruments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	7,856	20,099
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,671	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	3,233	150
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	2,753	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	1,248	1,451
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	1,505	720
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	2,654	0
Commercial Real Estate, Buildings, Land and Other [Member] | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Nonperforming Financial Instruments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	3,797
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	122
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	0
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	769,805	560,720
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	610,434	576,374
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	541,575	344,641
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	171,695	28,063
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	2,727	296
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	559	1,613
Financing Receivable, Excluding Accrued Interest, Revolving	167,122	169,017
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	159	0
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff	0
Construction Loans [Member] | Nonperforming Financial Instruments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0	0
Construction Loans [Member] | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Nonperforming Financial Instruments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Revolving	0
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0
Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff	4,940	2,883	912
Total consumer real estate loans [Member] | Nonperforming Financial Instruments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	47	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	38
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	92	2,281
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	2,202	483
Financing Receivable, Excluding Accrued Interest, Revolving	587	1,600
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	3,583	3,040
Total consumer real estate loans [Member] | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Nonperforming Financial Instruments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	537
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	315
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	253
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	704
Financing Receivable, Excluding Accrued Interest, Revolving	3,064
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	67
Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff	33,344	31,260	24,388
Consumer Loan [Member] | Nonperforming Financial Instruments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	352	0
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	0	0
Financing Receivable, Excluding Accrued Interest, Revolving	0	0
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	0	0
Consumer Loan [Member] | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Nonperforming Financial Instruments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year	24,485
Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year	5,793
Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year	218
Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year	56
Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year	30
Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year	71
Financing Receivable, Excluding Accrued Interest, Revolving	2,459
Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan	232
Loans Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff	$ 57,110	$ 53,931	$ 32,948

Loans (Investment in Loans Rela

Loans (Investment in Loans Related to Allowance for Loan Loss by Portfolio Segment Disaggregated Based on Impairment Methodology) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 20,754,813	$ 18,824,251
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	270,151	245,996
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	6,109,532	5,967,182
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	87,569	74,006	$ 104,237	$ 72,091
Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	1,128,895	936,737
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	9,992	17,814	18,062	17,217
Commercial Real Estate, Buildings, Land and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	7,704,447	7,301,920
Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	2,264,076	1,680,724
Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	3,103,389	2,460,726
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	19,106	13,538	8,004	6,585
Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	444,474	476,962
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	10,279	10,040	$ 7,017	$ 7,837
Specific Valuation Allowances [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	17,521	8,526
Specific Valuation Allowances [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	13,265	2,435
Specific Valuation Allowances [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	2,700	2,700
Specific Valuation Allowances [Member] | Commercial Real Estate, Buildings, Land and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	122	2,650
Specific Valuation Allowances [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	503	0
Specific Valuation Allowances [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	766	741
Specific Valuation Allowances [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest	165	0
Loans Individually Evaluated for Impairment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	76,287	58,631
Loans Individually Evaluated for Impairment [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	45,009	18,670
Loans Individually Evaluated for Impairment [Member] | Commercial and Industrial Total Energy Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	4,078	11,353
Loans Individually Evaluated for Impairment [Member] | Commercial Real Estate, Buildings, Land and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	18,797	21,373
Loans Individually Evaluated for Impairment [Member] | Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	2,012	0
Loans Individually Evaluated for Impairment [Member] | Total consumer real estate loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	6,039	7,235
Loans Individually Evaluated for Impairment [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned discounts	$ 352	$ 0

Premises and Equipment (Narrati

Premises and Equipment (Narrative) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Depreciation	$ 61,900	$ 60,600	$ 57,400
Operating Lease, Rent Expense	49,700	50,500	47,700
Operating Lease, Right-of-Use Asset	270,282	280,502
Operating lease, payments	33,700	32,100
Premises and Equipment
Property, Plant and Equipment [Line Items]
Operating Lease, Right-of-Use Asset	270,300	280,500
Other Liabilities [Member]
Property, Plant and Equipment [Line Items]
Operating lease, liability	308,053	316,400
Partnership Interest [Member]
Property, Plant and Equipment [Line Items]
Operating Lease, Rent Expense	$ 349	$ 337	$ 327

Premises and Equipment (Premise

Premises and Equipment (Premises and Equipment) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Land	$ 224,290	$ 191,594
Buildings	644,240	581,745
Technology, furniture and equipment	281,697	262,666
Leasehold improvements	250,572	230,642
Construction and projects in progress	24,135	36,910
Operating lease, right-of-use asset	270,282	280,502
Premises and equipment, Gross	1,695,216	1,584,059
Less accumulated depreciation and amortization	(449,839)	(394,026)
Total premises and equipment, net	$ 1,245,377	$ 1,190,033

Premises and Equipment (Lease C

Premises and Equipment (Lease Commitments, Components of Lease Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Amortization of lease right-of-use assets	$ 35,400	$ 34,137
Short-term lease expense	1,456	2,576
Non-lease components (including taxes, insurance, common maintenance, etc.)	12,835	13,811
Total operating lease expense, excluding rent	$ 49,691	$ 50,524

Premises and Equipment Future M

Premises and Equipment Future Minimum Lease Payments Due Under non-Cancelable Operating Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
2025	$ 36,953
2026	37,007
2027	35,958
2028	34,007
2029	29,795
Thereafter	206,868
Total undiscounted operating lease liability	380,588
Imputed interest	$ 72,535
Weighted-average lease term in years	12 years 4 months 20 days
Weighted-average discount rate	3.39%
Other Liabilities [Member]
Property, Plant and Equipment [Line Items]
Operating lease, liability	$ 308,053	$ 316,400

Deposits (Schedule of Deposits)

Deposits (Schedule of Deposits) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Deposit Liability [Line Items]
Non-interest-bearing demand deposits	$ 14,441,820	$ 14,926,094
Savings and interest checking	10,310,942	10,512,637
Money market accounts	11,568,254	10,997,279
Time accounts	6,401,732	5,484,558
Total Interest-bearing deposits	28,280,928	26,994,474
Total deposits	$ 42,722,748	$ 41,920,568

Deposits (Additional Informatio

Deposits (Additional Information About Corporation's Deposits) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Deposit Liability [Line Items]
Deposits from foreign sources (primarily Mexico)	$ 1,219,463	$ 1,061,701
Non-interest-bearing public funds deposits	14,441,820	14,926,094
Interest-bearing public funds deposits	28,280,928	26,994,474
Total deposits not covered by deposit insurance	22,972,618	22,393,786
Time deposits not covered by deposit insurance	2,744,112	2,339,716
Deposits from certain directors, executive officers and their affiliates	121,113	115,798
Public Funds [Member]
Deposit Liability [Line Items]
Non-interest-bearing public funds deposits	759,819	675,016
Interest-bearing public funds deposits	$ 625,104	$ 630,455

Deposits (Scheduled Maturities

Deposits (Scheduled Maturities of Time Deposits) (Detail) $ in Thousands	Dec. 31, 2024 USD ($)
Deposits [Abstract]
2025	$ 6,214,390
2026	17,636
2027	169,706
Time deposits, Total	$ 6,401,732

Deposits (Scheduled Maturitie_2

Deposits (Scheduled Maturities of Time Deposits Not Covered By Deposit Insurance) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Deposits [Abstract]
Due within 3 months or less	$ 2,500,536
Due after 3 months and within 6 months	91,140
Due after 6 months and within 12 months	107,808
Due after 12 months	44,628
Time deposits liability, above US Insurance Limit Total	$ 2,744,112	$ 2,339,716

Borrowed Funds (Narrative) (Det

Borrowed Funds (Narrative) (Detail) $ in Thousands		12 Months Ended
	Mar. 17, 2017 USD ($)	Dec. 31, 2024 USD ($) quarter	Dec. 31, 2023 USD ($)	Dec. 31, 2004 USD ($)
Borrowed Funds [Line Items]
Federal funds purchased		$ 21,975	$ 14,200
Repurchase agreements		4,342,941	4,127,188
Subordinated notes		99,648	99,491
Junior subordinated deferrable interest debentures		$ 123,184	123,127
Maximum number of quarterly periods by which the corporation has the right to defer interest payments on junior subordinated deferrable interest debentures | quarter		20
Cullen Frost Capital Trust II [Member]
Borrowed Funds [Line Items]
Maturity date				Mar. 01, 2034
Proceeds from Issuance of Trust Preferred Securities				$ 120,000
Floating rate 3 month SOFR plus margin				1.81%
Proceeds from issuance of Common Equity Securities				$ 3,700
Federal Funds Purchased [Member] | Minimum [Member]
Borrowed Funds [Line Items]
Short term debt maturity period		1 day
Federal Funds Purchased [Member] | Maximum [Member]
Borrowed Funds [Line Items]
Short term debt maturity period		90 days
Securities Loaned or Sold under Agreements to Repurchase [Member] | Minimum [Member]
Borrowed Funds [Line Items]
Short term debt maturity period		30 days
Securities Loaned or Sold under Agreements to Repurchase [Member] | Maximum [Member]
Borrowed Funds [Line Items]
Short term debt maturity period		90 days
Subordinated Debt [Member]
Borrowed Funds [Line Items]
Subordinated notes	$ 100,000
Subordinated notes interest rate	4.50%
Maturity date	Mar. 17, 2027
Unamortized debt issuance cost related to note		$ 352	509
Junior Subordinated Deferrable Interest Debenture [Member] | Cullen Frost Capital Trust II [Member]
Borrowed Funds [Line Items]
Unamortized debt issuance cost related to note		528	585
Junior subordinated deferrable interest debentures		$ 123,700	$ 123,700	$ 123,700
Floating rate 3 month SOFR plus margin		6.28%	7.19%

Off-Balance Sheet Arrangements

Off-Balance Sheet Arrangements Commitments Guarantees and Contingencies (Narrative) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Commitments And Guarantees [Line Items]
Off-Balance-Sheet, Credit Loss, Liability, Change in Method, Credit Loss Expense (Reversal)	$ 1,800	$ (19,000)
Credit card guarantees	4,900	5,500
Fully collateralized credit card guarantees	673	762
Consumer Loan [Member]
Commitments And Guarantees [Line Items]
Off-Balance-Sheet, Credit Loss, Liability, Change in Method, Credit Loss Expense (Reversal)	1,600
Commercial mortgage [Member]
Commitments And Guarantees [Line Items]
Off-Balance-Sheet, Credit Loss, Liability, Change in Method, Credit Loss Expense (Reversal)	211
Frost Wealth Advisors [Member]
Commitments And Guarantees [Line Items]
Fair value of off-balance sheet managed and custody assets	$ 51,400,000	$ 47,200,000	$ 42,900,000

Off-Balance-Sheet Arrangement_3

Off-Balance-Sheet Arrangements, Commitments, Guarantees and Contingencies (Financial Instruments With Off-Balance-Sheet Risk) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Standby Letters of Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial instruments with off- balance-sheet risk	$ 449,176	$ 438,635
Deferred Standby Letter of Credit Fees [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial instruments with off- balance-sheet risk	3,071	2,912
Commitments to Extend Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial instruments with off- balance-sheet risk	$ 12,046,520	$ 12,195,073

Off-Balance-Sheet Arrangement_4

Off-Balance-Sheet Arrangements, Commitments, Guarantees and Contingencies - Credit Losses on Off-Balance-Sheet Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Off-Balance Sheet, Credit Loss, Liability, Beginning Balance	$ 51,751	$ 58,593	$ 50,314
Off-Balance Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal)	153	(6,842)	8,279
Off-Balance Sheet, Credit Loss, Liability, Ending Balance	$ 51,904	$ 51,751	$ 58,593

Capital and Regulatory Matter_2

Capital and Regulatory Matters (Narrative) (Detail)					12 Months Ended
	Jan. 29, 2025 USD ($)	Jan. 24, 2024 USD ($)	Nov. 19, 2020 USD ($) $ / shares shares	Mar. 17, 2017 USD ($)	Dec. 31, 2024 USD ($) quarter $ / shares Rate shares	Dec. 31, 2023 USD ($) $ / shares Rate shares	Dec. 31, 2022 USD ($) shares	Jan. 01, 2019 Rate
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Credit loss optional transitional period under CECL					5 years
CECL Transition Amount					$ 15,400,000	$ 30,800,000
Subordinated notes					99,648,000	99,491,000
Treasury stock, shares, acquired | shares							0
Treasury Stock, Value, Acquired, Cost Method					$ (60,901,000)	$ (42,720,000)	$ (4,391,000)
Excise Tax Percentage | Rate					1%
Aggregate dividends available for payment without prior regulatory approval					$ 1,200,000,000
Maximum number of quarterly periods by which the corporation has the right to defer interest payments on junior subordinated deferrable interest debentures | quarter					20
Treasury Stock, Common
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Treasury stock, shares, acquired | shares					577,637	436,765	31,351
Series B Preferred Stock [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Non-cumulative perpetual preferred stock, dividend rate percentage			4.45%
Preferred Stock, Shares Issued | shares			150,000		150,000	150,000
Preferred Stock, Aggregate Liquidation Preference, Value			$ 150,000,000		$ 1,000	$ 1,000
Preferred Stock, Par or Stated Value Per Share | $ / shares			$ 0.01		$ 0.01	$ 0.01
Liquidation preference per share | $ / shares			$ 1,000
Number of Preferred Stock equivalent depositary shares | shares			40
Payments of Stock Issuance Costs			$ 4,500,000
Proceeds from issuance of preferred stock			$ 145,500,000
Series B Preferred Stock Equivalent Depositary Shares Member [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Liquidation preference per share | $ / shares			$ 25
Subordinated Debt [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Subordinated notes				$ 100,000,000
Subordinated notes interest rate				4.50%
Per year percentage of decreases in permissible portion of Subordinate Note included in Total Capital					20%
Final years of the term of the notes					5 years
Cullen/Frost [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Additional Tier 1 Capital beyond Common Equity Tier 1					$ 145,500,000	$ 145,500,000
Non-cumulative perpetual preferred stock, dividend rate percentage			4.45%
Common Equity Tier One Risk Based Capital To Risk Weighted Assets Minimum Capital Required Basel III Phase In Schedule, Ratio								4.50%
Capital Conservation Buffer								2.50%
Effective common equity tier one capital to risk weighted assets, ratio upon full implementation					7%	7%		7%
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets | Rate								6%
Effective tier one capital ratio, upon full implementation					8.50%	8.50%		8.50%
Minimum ratio of Total capital to risk weighted assets | Rate					15.53%	15.18%		8%
Tier one risk based capital to risk weighted assets, ratio upon full implementation					10.50%	10.50%		10.50%
Minimum leverage ratio					4%	4%		4%
Cullen/Frost [Member] | Trust Preferred Securities Tier Two Capital Allowable Portion [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Trust preferred securities					$ 120,000,000	$ 120,000,000
Cullen/Frost [Member] | Subordinated Debt [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Permissible Portion Of Subordinated Note Included In Capital					40,000,000	60,000,000
Frost Bank [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Additional Tier 1 Capital beyond Common Equity Tier 1					$ 0	$ 0
Common Equity Tier One Risk Based Capital To Risk Weighted Assets Minimum Capital Required Basel III Phase In Schedule, Ratio								4.50%
Capital Conservation Buffer								2.50%
Effective common equity tier one capital to risk weighted assets, ratio upon full implementation					7%	7%		7%
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets | Rate								6%
Effective tier one capital ratio, upon full implementation					8.50%	8.50%		8.50%
Minimum ratio of Total capital to risk weighted assets | Rate					14.72%	14.20%		8%
Tier one risk based capital to risk weighted assets, ratio upon full implementation					10.50%	10.50%		10.50%
Minimum leverage ratio					4%	4%		4%
stock repurchase 2025 plan | Subsequent Event
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Share repurchase authorized amount	$ 150,000,000
Stock repurchase program, period in force	1 year
stock repurchase 2024 plan
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Share repurchase authorized amount		$ 150,000,000
Stock repurchase program, period in force		1 year
stock repurchase 2024 plan | Treasury Stock, Common
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Treasury stock, shares, acquired | shares					489,862
Treasury Stock, Value, Acquired, Cost Method					$ (50,000,000)
stock repurchase 2023 plan | Treasury Stock, Common
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Treasury stock, shares, acquired | shares					400,868
Treasury Stock, Value, Acquired, Cost Method					$ (39,000,000)
Share awards vesting | Treasury Stock, Common
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Treasury stock, shares, acquired | shares					87,775	35,897	31,351
Treasury Stock, Value, Acquired, Cost Method					$ (10,900,000)	$ (3,500,000)	$ (4,400,000)

Regulatory Matters (Actual and

Regulatory Matters (Actual and Required Capital Ratios) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Jan. 01, 2019
Cullen/Frost [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier One to Risk-Weighted Assets, Actual, Capital Amount	$ 4,343,666	$ 4,036,945
Common Equity Tier One Risk-Based Capital Ratio, Actual	13.62%	13.25%
Common Equity Tier One Capital Required For Capital Adequacy Minimum Capital Required Plus Capital Conservation Buffer, Capital Amount	$ 2,232,822	$ 2,132,516
Common Equity Tier One Risk Based Capital To Risk Weighted Assets Minimum Capital Required Plus Capital Conservation Buffer, Ratio	7%	7%	7%
Tier 1 Capital to Risk-Weighted Assets, Actual, Capital Amount	$ 4,489,118	$ 4,182,397
Tier 1 Capital to Risk-Weighted Assets, Actual, Ratio	14.07%	13.73%
Tier One Risk Based Capital Required For Capital Adequacy Minimum Capital Required Plus Capital Conservation Buffer, Capital Amount	$ 2,711,283	$ 2,589,484
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets Minimum Capital Required Plus Capital Conservation Buffer, Ratio	8.50%	8.50%	8.50%
Tier 1 Capital to Risk-Weighted Assets, Required to be Considered Well Capitalized, Capital Amount	$ 1,913,847	$ 1,827,871
Tier 1 Capital to Risk-Weighted Assets, Required to be Considered Well Capitalized, Ratio	6%	6%
Total Capital to Risk-Weighted Assets, Actual, Capital Amount	$ 4,954,136	$ 4,625,760
Total Capital to Risk-Weighted Assets, Actual, Ratio	15.53%	15.18%	8%
Capital Required for Capital Adequacy Minimum Capital Required Plus Capital Conservation Buffer, Capital Amount	$ 3,349,232	$ 3,198,774
Capital Required for Capital Adequacy to Risk Weighted Assets Minimum Capital Required Plus Capital Conservation Buffer, Ratio	10.50%	10.50%	10.50%
Total Capital to Risk-Weighted Assets, Required to be Considered Well Capitalized, Capital Amount	$ 3,189,745	$ 3,046,452
Total Capital to Risk-Weighted Assets, Required to be Considered Well Capitalized, Ratio	10%	10%
Leverage Ratio, Actual, Capital Amount	$ 4,489,118	$ 4,182,397
Leverage Ratio, Actual, Ratio	8.63%	8.35%
Tier One Leverage Capital Required for Capital Adequacy Minimum Capital Required Plus Capital Conservation Buffer, Capital Amount	$ 2,079,715	$ 2,003,020
Tier One Leverage Capital Required for Capital Adequacy to Average Assets Minimum Capital Required Plus Capital Conservation Buffer, Ratio	4%	4%	4%
Frost Bank [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier One to Risk-Weighted Assets, Actual, Capital Amount	$ 4,387,862	$ 4,057,111
Common Equity Tier One Risk-Based Capital Ratio, Actual	13.76%	13.33%
Common Equity Tier One Capital Required For Capital Adequacy Minimum Capital Required Plus Capital Conservation Buffer, Capital Amount	$ 2,231,710	$ 2,129,784
Common Equity Tier One Risk Based Capital To Risk Weighted Assets Minimum Capital Required Plus Capital Conservation Buffer, Ratio	7%	7%	7%
Common Equity Tier One Capital Required To Be Well Capitalized, Capital Amount	$ 2,072,302	$ 1,977,656
Common Equity Tier One Risk-Based Capital Ratio, Well Capitalized, Minimum	6.50%	6.50%
Tier 1 Capital to Risk-Weighted Assets, Actual, Capital Amount	$ 4,387,862	$ 4,057,111
Tier 1 Capital to Risk-Weighted Assets, Actual, Ratio	13.76%	13.33%
Tier One Risk Based Capital Required For Capital Adequacy Minimum Capital Required Plus Capital Conservation Buffer, Capital Amount	$ 2,709,934	$ 2,586,166
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets Minimum Capital Required Plus Capital Conservation Buffer, Ratio	8.50%	8.50%	8.50%
Tier 1 Capital to Risk-Weighted Assets, Required to be Considered Well Capitalized, Capital Amount	$ 2,550,526	$ 2,434,038
Tier 1 Capital to Risk-Weighted Assets, Required to be Considered Well Capitalized, Ratio	8%	8%
Total Capital to Risk-Weighted Assets, Actual, Capital Amount	$ 4,692,880	$ 4,320,474
Total Capital to Risk-Weighted Assets, Actual, Ratio	14.72%	14.20%	8%
Capital Required for Capital Adequacy Minimum Capital Required Plus Capital Conservation Buffer, Capital Amount	$ 3,347,565	$ 3,194,676
Capital Required for Capital Adequacy to Risk Weighted Assets Minimum Capital Required Plus Capital Conservation Buffer, Ratio	10.50%	10.50%	10.50%
Total Capital to Risk-Weighted Assets, Required to be Considered Well Capitalized, Capital Amount	$ 3,188,157	$ 3,042,548
Total Capital to Risk-Weighted Assets, Required to be Considered Well Capitalized, Ratio	10%	10%
Leverage Ratio, Actual, Capital Amount	$ 4,387,862	$ 4,057,111
Leverage Ratio, Actual, Ratio	8.44%	8.10%
Tier One Leverage Capital Required for Capital Adequacy Minimum Capital Required Plus Capital Conservation Buffer, Capital Amount	$ 2,079,965	$ 2,003,152
Tier One Leverage Capital Required for Capital Adequacy to Average Assets Minimum Capital Required Plus Capital Conservation Buffer, Ratio	4%	4%	4%
Leverage Ratio, Required to be Considered Well Capitalized, Capital Amount	$ 2,599,956	$ 2,503,940
Leverage Ratio, Required to be Considered Well Capitalized, Ratio	5%	5%

Earnings Per Common Share (Basi

Earnings Per Common Share (Basic and Diluted Earnings Per Common Share) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Earnings Per Share [Abstract]
Net income (loss)	$ 582,542	$ 597,973	$ 579,150
Less: Preferred stock dividends	6,675	6,675	6,675
Net income (loss) available to common shareholders	575,867	591,298	572,475
Less: Earnings allocated to participating securities	6,236	6,283	5,210
Net earnings allocated to common stock	569,631	585,015	567,265
Distributed earnings allocated to common stock	239,879	229,749	207,924
Undistributed earnings allocated to common stock	$ 329,752	$ 355,266	$ 359,341
Weighted-average shares outstanding for basic earnings per common share	64,120,455	64,204,239	64,156,870
Dilutive effect of stock compensation	142,191	200,594	363,648
Weighted-average shares outstanding for diluted earnings per common share	64,262,646	64,404,833	64,520,518

Employee Benefit Plans (Narrati

Employee Benefit Plans (Narrative) (Detail) - USD ($)		12 Months Ended
	Apr. 24, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Percentage of equity investments in mutual fund		74%
Net periodic benefit cost, Expected return on plan assets		5.70%	7%	7.25%
Expected defined benefit plans contribution within a year		$ 1,100,000
Participants contribution eligible for match		100%
Defined contribution plan, cost		$ 30,400,000	$ 32,300,000	$ 28,000,000
Number of stock plans		3
Options awarded during period		0	0	0
Dividends, share-based compensation		$ 0.95	$ 0.92	$ 0.87
Weighted-average risk-free interest rate		4.09%	5.01%	4.45%
Performance Shares [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares available for grant		2,361,570
Performance Shares [Member] | Pro Forma [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Granted in period, number of shares/units		21,554	66,471	35,015
Share-based Payment Arrangement, Option [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period		10 years
Weighted-Average Exercise Price, Options Outstanding		$ 65.11
Weighted- Average Remaining Contractual Life in Years		9 months 25 days
Options Exercisable [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value		$ 12,700,000
Equity Securities [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Target asset allocation percentage		31%
Fixed Income Securities [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Target asset allocation percentage		64%
Two Thousand Twenty-Four Plan [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized	2,576,038
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized	2,350,000
Two Thousand Twenty-Four Plan [Member] | Stock Options [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period		10 years
Vesting period of options awarded, years		4 years
Two Thousand Twenty-Four Plan [Member] | Non Vested Stock Awards and Stock Units [Member] | Prior to 2021
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Vesting period of options awarded, years		4 years
Two Thousand Twenty-Four Plan [Member] | Non Vested Stock Awards and Stock Units [Member] | 2023
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Vesting period of options awarded, years		3 years
Two Thousand Twenty-Four Plan [Member] | Non Vested Stock Awards and Stock Units [Member] | 2022
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Vesting period of options awarded, years		3 years
Two Thousand Twenty-Four Plan [Member] | Non Vested Stock Awards and Stock Units [Member] | 2024
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Vesting period of options awarded, years		3 years
Superseded 2015 Plan [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized	226,038
Minimum [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Maximum annual contributions per employee, percent		2%
Maximum [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Maximum annual contributions per employee, percent		50%
Employer matching contribution, percent of employees' gross pay		6%
Maximum [Member] | Performance Shares [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Granted in period, number of shares/units		32,334	99,710	52,527

Employee Benefit Plans (Combine

Employee Benefit Plans (Combined Activity in Corporations Defined Benefit Pension Plans) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Retirement Benefits [Abstract]
Fair value of plan assets at beginning of year	$ 174,611	$ 161,823	$ 197,747
Actual return on plan assets	5,306	22,477	(26,108)
Employer contributions	1,150	1,105	1,114
Benefits paid	(11,340)	(10,794)	(10,930)
Fair value of plan assets at end of year	169,727	174,611	161,823
Benefit obligation at beginning of year	142,372	143,944	185,925
Interest cost	6,647	6,983	4,017
Actuarial (gain) loss	(6,779)	2,239	(35,068)
Benefits paid	(11,340)	(10,794)	(10,930)
Benefit obligation at end of year	130,900	142,372	143,944
Funded status of the plan at end of year and accrued benefit (liability) recognized	38,827	32,239	17,879
Accumulated benefit obligation at end of year	$ 130,900	$ 142,372	$ 143,944

Employee Benefit Plans (Disaggr

Employee Benefit Plans (Disaggregated Information Related to Corporations Defined Benefit Pension Plans) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 130,900	$ 142,372	$ 143,944	$ 185,925
Accumulated benefit obligation	130,900	142,372	143,944
Fair value of plan assets	169,727	174,611	161,823	$ 197,747
Funded status of the plan at end of year and accrued benefit (liability) recognized	38,827	32,239	$ 17,879
Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	120,179	130,750
Accumulated benefit obligation	120,179	130,750
Fair value of plan assets	169,727	174,611
Funded status of the plan at end of year and accrued benefit (liability) recognized	49,548	43,861
Restoration Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	10,721	11,622
Accumulated benefit obligation	10,721	11,622
Fair value of plan assets	0	0
Funded status of the plan at end of year and accrued benefit (liability) recognized	$ (10,721)	$ (11,622)

Employee Benefit Plans (Net Per

Employee Benefit Plans (Net Periodic Benefit Cost (Benefit)) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Retirement Benefits [Abstract]
Expected return on plan assets, net of expenses	$ (9,645)	$ (10,959)	$ (13,966)
Interest cost on projected benefit obligation	6,647	6,983	4,017
Net amortization and deferral	1,673	3,479	2,964
Net periodic expense (benefit)	$ (1,325)	$ (497)	$ (6,985)

Employee Benefit Plans (Defined

Employee Benefit Plans (Defined Benefit Pension Plans Recognized as Component of Other Comprehensive Income) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Net actuarial gain (loss)	$ 4,112	$ 12,757	$ (2,041)
Deferred tax (expense) benefit	(863)	(2,679)	429
Other comprehensive income (loss), net of tax	$ 3,249	$ 10,078	$ (1,612)

Employee Benefit Plans (Defin_2

Employee Benefit Plans (Defined Benefit Pension Plans not Recognized as Component of Combined Net Period Benefit Cost) (Detail) - Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ (26,806)	$ (30,918)
Deferred tax benefit	5,630	6,493
Amounts included in accumulated other comprehensive loss, net of tax	$ (21,176)	$ (24,425)

Employee Benefit Plans (Weighte

Employee Benefit Plans (Weighted-Average Assumptions Used to Determine Benefit Obligations) (Detail)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Retirement Benefits [Abstract]
Benefit obligations, Discount rate	5.58%	4.95%	5.14%
Net periodic benefit cost, Discount rate	4.95%	5.14%	2.79%
Net periodic benefit cost, Expected return on plan assets	5.70%	7%	7.25%

Employee Benefit Plans (Fair Va

Employee Benefit Plans (Fair Value of Plan Assets) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 169,727	$ 174,611	$ 161,823	$ 197,747
Mutual Fund [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	34,564	38,793
US Treasury [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	24,341	26,633
Common Stock [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14,921	13,001
Cash and Cash Equivalents [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	431	1,241
Corporate Bond Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	62,405	58,669
US Government Agencies Debt Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7,232	7,041
States and Political Subdivisions [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 25,833	$ 29,233

Employee Benefit Plans (Expecte

Employee Benefit Plans (Expected Future Benefit Payments Related to Defined Benefit Plans) (Detail) $ in Thousands	Dec. 31, 2024 USD ($)
Retirement Benefits [Abstract]
2025	$ 12,080
2026	12,025
2027	11,905
2028	11,596
2029	11,488
2030 through 2034	49,199
Total defined benefit plan expected future benefit payments	$ 108,293

Employee Benefit Plans (Summary

Employee Benefit Plans (Summary of Activity in Corporation's Active Stock Plans) (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options exercised, number of shares	(589,782)	(267,357)	(399,810)
Director deferred stock units outstanding [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ending balance, number of shares/units	52,779	54,164	45,661
Beginning balance, number of shares/units	54,164	45,661	56,301
Ending balance, weighted-average grant-date fair value	$ 95.37	$ 89.71	$ 87.15
Beginning balance, weighted-average grant-date fair value	$ 89.71	$ 87.15	$ 79.21
Granted in period, number of shares/units	7,997	8,503	5,382
Granted in period, weighted-average grant-date fair value	$ 116.84	$ 103.47	$ 133.67
Stock awards exercised/vested in period, number of shares	(9,382)	0	(16,022)
Stock awards exercised/vested in period, weighted-average grant date fair value	$ 80.99	$ 0	$ 74.89
Non-Vested Stock Awards/ Stock Units Outstanding [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ending balance, number of shares/units	507,862	566,806	465,319
Beginning balance, number of shares/units	566,806	465,319	449,337
Ending balance, weighted-average grant-date fair value	$ 113.72	$ 99.77	$ 105.36
Beginning balance, weighted-average grant-date fair value	$ 99.77	$ 105.36	$ 93.05
Granted in period, number of shares/units	176,892	217,561	119,176
Granted in period, weighted-average grant-date fair value	$ 129.44	$ 85.39	$ 142.56
Stock awards exercised/vested in period, number of shares	(232,617)	(108,920)	(97,154)
Stock awards exercised/vested in period, weighted-average grant date fair value	$ 91.78	$ 94	$ 94.81
Forfeited/expired in period, number of shares/units	(3,219)	(7,154)	(6,040)
Forfeited/expired in period, weighted-average grant date fair value	$ 106.74	$ 114.53	$ 93.28
Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ending balance, number of shares	183,976	485,941	616,227
Beginning balance, number of shares	485,941	616,227	877,681
Ending balance, weighted-average exercise price	$ 65.11	$ 71.25	$ 71.27
Beginning balance, weighted-average exercise price	$ 71.25	$ 71.27	$ 69.02
Stock options exercised, number of shares	(301,965)	(130,286)	(261,454)
Stock options exercised, weighted-average exercise price	$ 74.98	$ 71.37	$ 63.72
Maximum [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ending balance, number of shares/units	230,657	267,054	213,749
Beginning balance, number of shares/units	267,054	213,749	202,460
Ending balance, weighted-average grant-date fair value	$ 103.65	$ 89.99	$ 96.20
Beginning balance, weighted-average grant-date fair value	$ 89.99	$ 96.20	$ 84.71
Granted in period, number of shares/units	32,334	99,710	52,527
Granted in period, weighted-average grant-date fair value	$ 119.17	$ 74.71	$ 133.40
Stock awards exercised/vested in period, number of shares	(45,818)	(28,151)	(25,180)
Stock awards exercised/vested in period, weighted-average grant date fair value	$ 57.89	$ 85.74	$ 87.18
Forfeited/expired in period, number of shares/units	(22,913)	(18,254)	(16,058)
Forfeited/expired in period, weighted-average grant date fair value	$ 57.89	$ 85.74	$ 87.18

Employee Benefit Plans (Shares

Employee Benefit Plans (Shares Issued in Connection with Stock Compensation Awards) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Retirement Benefits [Abstract]
New shares issued from available authorized shares	0	49,887	118,389
Shares issued from available treasury stock	589,782	217,470	281,421
Total	589,782	267,357	399,810
Proceeds from stock option exercises	$ 22,643	$ 9,299	$ 16,659
Intrinsic value of stock options exercised	13,454	3,614	19,616
Fair value of restricted/director deferred stock units vested	$ 35,922	$ 13,445	$ 19,308

Employee Benefit Plans (Stock-B

Employee Benefit Plans (Stock-Based Compensation Expense) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-Based Payment Arrangement, Expense	$ 19,763	$ 24,590	$ 18,322
Income tax benefit	4,776	4,120	2,969
Non-Vested Stock Awards/ Stock Units Outstanding [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Non-vested restricted stock units	19,457	16,734	13,162
Director deferred stock units outstanding [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Non-vested restricted stock units	934	880	720
Performance Shares [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Non-vested restricted stock units		$ 6,976	$ 4,440
Restricted Stock or Unit Expense Reversal	$ (628)

Employee Benefit Plans (Unrecog

Employee Benefit Plans (Unrecognized Stock-Based Compensation Expense) (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($)
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Non-vested stock awards/stock units	$ 25,827
Performance stock units	12,912
Total	$ 38,739
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	2 years 2 months 12 days
Employee service share-based compensation, Performance stock units,compensation cost not yet recognized,period for recognition	2 years 7 days

Other Non-Interest Income and_3

Other Non-Interest Income and Expense (Narrative) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Other Income and Expenses [Abstract]
Minimum percentage of the aggregate total net interest income and total non interest income required for amounts to be stated separately	1%	1%	1%
Payment for services provided by related party	$ 1,800	$ 1,300	$ 545

Other Non-Interest Income and_4

Other Non-Interest Income and Expense (Other Non-Interest Income and Expense) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Other Income and Expenses [Abstract]
Other	$ 52,060	$ 54,941	$ 45,217
Total other non-interest income	52,060	54,941	45,217
Professional services	56,385	53,932	40,908
Advertising, promotions and public relations	51,403	48,608	39,994
Other	136,623	126,827	113,799
Total other non-interest expense	$ 244,411	$ 229,367	$ 194,701

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
U.S. federal statutory income tax rate	21%	21%	21%
Unrecognized tax benefits	$ 0	$ 0	$ 0
Valuation allowance	$ 0	$ 0

Income Taxes (Income Tax Expens

Income Taxes (Income Tax Expense) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Current income tax expense	$ 125,025	$ 129,229	$ 94,595
Deferred income tax expense (benefit)	(11,600)	(14,829)	(4,918)
Income tax expense, as reported	$ 113,425	$ 114,400	$ 89,677
Effective tax rate	16.30%	16.10%	13.40%

Income Taxes (Income Tax Comput

Income Taxes (Income Tax Computed by Applying U.S. Federal Statutory Income Tax Rate) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income tax expense computed at the statutory rate	$ 146,153	$ 149,598	$ 140,454
Effect of tax-exempt interest	(38,498)	(43,114)	(50,602)
Net tax benefit from stock-based compensation	(3,795)	(894)	(4,602)
Tax benefit on dividends paid in our 401k plan	(2,281)	(2,135)	(1,854)
Non-deductible FDIC premiums	5,943	5,263	3,277
Non-deductible meals and entertainment	1,861	1,692	683
Non-deductible compensation	1,629	2,591	2,250
Other	2,413	1,399	71
Income tax expense, as reported	$ 113,425	$ 114,400	$ 89,677

Income Taxes (Schedule of Defer

Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Net unrealized loss on securities available for sale and transferred securities	$ 327,184	$ 291,023
Allowance for credit losses	67,697	62,592
Lease liabilities under operating leases	64,691	66,442
Bonus accrual	13,753	9,680
FDIC deposit insurance special assessment	8,647	9,468
Stock-based compensation	6,321	7,712
Net actuarial loss on defined benefit post-retirement benefit plans	5,630	6,493
Deferred loan and lease origination fees	3,990	4,129
Other	6,496	5,892
Total gross deferred tax assets	504,409	463,431
Right-of-use assets under operating leases	(56,759)	(58,905)
Premises and equipment	(38,352)	(42,640)
Intangible assets	(18,048)	(18,106)
Defined benefit post-retirement benefit plans	(13,591)	(13,073)
Other	(2,422)	(2,368)
Total gross deferred tax liabilities	(129,172)	(135,092)
Deferred Tax Assets, Net	$ 375,237	$ 328,339

Other Comprehensive Income (L_3

Other Comprehensive Income (Loss) (Component of Other Comprehensive Income (Loss)) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Equity [Abstract]
Securities available for sale and transferred securities, Change in net unrealized gain/loss during the period, before tax amount	$ (171,662)	$ 277,926	$ (2,143,567)
Securities available for sale and transferred securities, Change in net unrealized gain on securities transferred to held to maturity, before tax amount	(629)	(649)	(737)
Securities available for sale and transferred securities, Reclassification adjustment for net (gains) losses included in net income, before tax amount	96	(66)	0
Total securities available for sale and transferred securities before tax amount	(172,195)	277,211	(2,144,304)
Change in the net actuarial gain/loss before tax amount	2,439	9,278	(5,005)
Reclassification adjustment for net amortization of actuarial gain/loss included in net income as a component of net periodic cost (benefit) before tax amount	1,673	3,479	2,964
Total defined-benefit post-retirement benefit plans	4,112	12,757	(2,041)
Other comprehensive income (loss), before tax	(168,083)	289,968	(2,146,345)
Securities available for sale and transferred securities, Change in net unrealized gain/loss during the period, tax expense (benefit)	(36,049)	58,364	(450,149)
Securities available for sale and transferred securities, change in net unrealized gain on securities transfers to held-to-maturity, tax expense benefit	(132)	(136)	(155)
Securities available for sale and transferred securities, Reclassification adjustment for net (gains) losses included in net income, tax expense (benefit)	20	(14)
Total securities available for sale and transferred securities, tax expense (benefit)	(36,161)	58,214	(450,304)
Change in the net actuarial gain/loss, tax expense (benefit)	512	1,948	(1,051)
Reclassification adjustment for net amortization of actuarial gain/loss included in net income as a componet of net periodic cost (benefit) , tax expense (benefit)	351	731	622
Total defined-benefit post-retirement benefit plans, tax expense (benefit)	863	2,679	(429)
Total other comprehensive income, tax expense (benefit)	(35,298)	60,893	(450,733)
Securities available for sale and transferred securities, change in net unrealized gain/loss during the period, net of tax amount	(135,613)	219,562	(1,693,418)
Securities available for sale and transferred securities. change in net unrealized gain on securities transfers to held-to-maturity, net of tax amount	(497)	(513)	(582)
Securities available for sale and securities transferred, reclassification adjustment for net (gains) losses included in net income, net of tax amount	76	(52)
Total securities available for sale and transferred securities, net of tax amount	(136,034)	218,997	(1,694,000)
Change in the net actuarial gain/loss, net of tax amount	1,927	7,330	(3,954)
Reclassification adjustment for net amortization of actuarial gain/loss included in net income as a componet of net periodic cost (benefit), net of tax amount	1,322	2,748	2,342
Total defined-benefit post-retirement benefit plans, net of tax amount	3,249	10,078	(1,612)
Other comprehensive income (loss), net of tax	$ (132,785)	$ 229,075	$ (1,695,612)

Other Comprehensive Income (Sch

Other Comprehensive Income (Schedule of Accumulated Other Comprehensive Income, Net of Tax) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	$ (1,119,219)
Net other comprehensive income (loss) during period	(132,785)	$ 229,075	$ (1,695,612)
Ending Balance	(1,252,004)	(1,119,219)
Available-for-sale Securities [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(1,094,794)	(1,313,791)	380,209
Other comprehensive income (loss) before reclassification	(136,110)	219,049	(1,694,000)
Reclassification of amounts included in net income	76	(52)	0
Net other comprehensive income (loss) during period	(136,034)	218,997	(1,694,000)
Ending Balance	(1,230,828)	(1,094,794)	(1,313,791)
Defined Benefit Plans [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(24,425)	(34,503)	(32,891)
Other comprehensive income (loss) before reclassification	1,927	7,330	(3,954)
Reclassification of amounts included in net income	1,322	2,748	2,342
Net other comprehensive income (loss) during period	3,249	10,078	(1,612)
Ending Balance	(21,176)	(24,425)	(34,503)
AOCI Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(1,119,219)	(1,348,294)	347,318
Other comprehensive income (loss) before reclassification	(134,183)	226,379	(1,697,954)
Reclassification of amounts included in net income	1,398	2,696	2,342
Net other comprehensive income (loss) during period	(132,785)	229,075	(1,695,612)
Ending Balance	$ (1,252,004)	$ (1,119,219)	$ (1,348,294)

Derivative Financial Instrume_3

Derivative Financial Instruments (Narrative) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Derivative [Line Items]
Weighted-average strike rate for outstanding interest rate caps	3.66%
Approximate credit exposure related to swaps with bank customers	$ 9,500
Cash collateral on deposit with other financial institutions	350	$ 8,600
Interest Rate Swaps With Financial Institution Counterparties [Member]
Derivative [Line Items]
Approximate credit exposure related to swaps with bank customers	1,500
Not Designated as Hedging Instrument [Member] | Financial Institution Counterparties Loan Lease Interest Rate Swaps Liabilities [Member]
Derivative [Line Items]
Estimated fair value of derivative contracts cleared through Chicago Mercantile Exchange	$ 0	$ 0

Derivative Financial Instrume_4

Derivative Financial Instruments (Schedule of Notional Amounts and Estimated Fair Values of Interest Rate Derivative Contracts Outstanding) (Detail) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Financial Institution Counterparties Loan Lease Interest Rate Swaps Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	$ 1,213,519	$ 1,040,659
Estimated Fair Value	63,001	58,486
Financial Institution Counterparties Loan Lease Interest Rate Swaps Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Notional Amount	663,078	617,266
Estimated Fair Value	(9,068)	(20,293)
Financial Institution Counterparties Loan Lease Interest Rate Caps Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	205,164	275,000
Estimated Fair Value	7,053	11,747
Customer Counterparties Loan Lease Interest Rate Swaps Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	663,078	617,266
Estimated Fair Value	9,068	20,482
Customer Counterparties Loan Lease Interest Rate Swaps Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Notional Amount	1,213,519	1,040,659
Estimated Fair Value	(63,000)	(58,485)
Customer Counterparties Loan Lease Interest Rate Caps Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Notional Amount	205,164	275,000
Estimated Fair Value	$ (7,054)	$ (11,747)

Derivative Financial Instrume_5

Derivative Financial Instruments (Schedule of Weighted-Average Rates Paid and Received for Interest Rate Swaps Outstanding) (Detail)	Dec. 31, 2024
Financial Institution Counterparties [Member] | Weighted Average Interest Rate Paid [Member]
Short-duration Insurance Contracts, Discounted Liabilities [Line Items]
Non-hedging interest rate swaps - financial institution counterparties	5.08%
Financial Institution Counterparties [Member] | Weighted-Average Interest Rate Received [Member]
Short-duration Insurance Contracts, Discounted Liabilities [Line Items]
Non-hedging interest rate swaps - financial institution counterparties	6.26%
Customer Counterparties [Member] | Weighted Average Interest Rate Paid [Member]
Short-duration Insurance Contracts, Discounted Liabilities [Line Items]
Non-hedging interest rate swaps - customer counterparties	6.26%
Customer Counterparties [Member] | Weighted-Average Interest Rate Received [Member]
Short-duration Insurance Contracts, Discounted Liabilities [Line Items]
Non-hedging interest rate swaps - customer counterparties	5.08%

Derivative Financial Instrume_6

Derivative Financial Instruments (Schedule of Notional Amounts and Estimated Fair Values of Commodity Derivative Positions) (Detail) bbl in Thousands, MMBTU in Thousands, $ in Thousands	Dec. 31, 2024 USD ($) bbl MMBTU	Dec. 31, 2023 USD ($) MMBTU bbl
Financial Institution Counterparties [Member] | Oil Commodity Derivative [Member]
Derivative Instruments [Line Items]
Oil/Natural Gas Derivative Assets Notional Amount | bbl	7,097	5,601
Oil/Natural Gas Derivative Assets, Estimated Fair Value	$ 27,471	$ 37,667
Oil/Natural Gas Derivative Liabilities Notional Amount | bbl	4,768	4,581
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value	$ (12,897)	$ (18,500)
Financial Institution Counterparties [Member] | Natural Gas Commodity Derivative [Member]
Derivative Instruments [Line Items]
Oil/Natural Gas Derivative Assets Notional Amount | MMBTU	25,454	17,363
Oil/Natural Gas Derivative Assets, Estimated Fair Value	$ 3,804	$ 11,822
Oil/Natural Gas Derivative Liabilities Notional Amount | MMBTU	26,082	6,462
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value	$ (4,054)	$ (2,499)
Customer Counterparties [Member] | Oil Commodity Derivative [Member]
Derivative Instruments [Line Items]
Oil/Natural Gas Derivative Assets Notional Amount | bbl	4,872	4,618
Oil/Natural Gas Derivative Assets, Estimated Fair Value	$ 12,973	$ 18,722
Oil/Natural Gas Derivative Liabilities Notional Amount | bbl	6,993	5,564
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value	$ (26,753)	$ (36,877)
Customer Counterparties [Member] | Natural Gas Commodity Derivative [Member]
Derivative Instruments [Line Items]
Oil/Natural Gas Derivative Assets Notional Amount | MMBTU	26,767	6,462
Oil/Natural Gas Derivative Assets, Estimated Fair Value	$ 4,255	$ 2,499
Oil/Natural Gas Derivative Liabilities Notional Amount | MMBTU	24,769	17,363
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value	$ (3,600)	$ (11,571)

Derivative Financial Instrume_7

Derivative Financial Instruments Derivative Financial Instruments (Schedule of Notional Amount and Fair Value of Open Foreign Currency Forward Contract) (Details) € in Thousands, $ in Thousands, $ in Thousands	Dec. 31, 2024 USD ($)	Dec. 31, 2024 CAD ($)	Dec. 31, 2024 EUR (€)	Dec. 31, 2023 USD ($)	Dec. 31, 2023 CAD ($)	Dec. 31, 2023 EUR (€)
Financial Institution Counterparties [Member] | Other Assets [Member] | Not Designated as Hedging Instrument [Member]
Derivative Counter Party [Line Items]
Forward Contracts - Assets, Notional Amount		$ 0			$ 250
Financial Institution Counterparties [Member] | Other Liabilities [Member] | Not Designated as Hedging Instrument [Member]
Derivative Counter Party [Line Items]
Forward Contracts Liability, Notional Amount		0	€ 0		250	€ 3,000
Customer Counterparties [Member] | Other Assets [Member] | Not Designated as Hedging Instrument [Member]
Derivative Counter Party [Line Items]
Forward Contracts - Assets, Notional Amount		0	€ 0		250	€ 3,000
Customer Counterparties [Member] | Other Liabilities [Member] | Not Designated as Hedging Instrument [Member]
Derivative Counter Party [Line Items]
Forward Contracts Liability, Notional Amount		$ 0			$ 250
GBP Foreign Exchange Forward [Member] | Financial Institution Counterparties [Member]
Derivative Counter Party [Line Items]
Forward Contracts, Liability Estimated Fair Value	$ 0			$ (14)
GBP Foreign Exchange Forward [Member] | Customer Counterparties [Member]
Derivative Counter Party [Line Items]
Forward Contracts - Assets Estimated Fair Value	0			16
Foreign Exchange Forward [Member] | Financial Institution Counterparties [Member]
Derivative Counter Party [Line Items]
Forward Contracts - Assets Estimated Fair Value	0			1
Forward Contracts, Liability Estimated Fair Value	0			(5)
Foreign Exchange Forward [Member] | Customer Counterparties [Member]
Derivative Counter Party [Line Items]
Forward Contracts - Assets Estimated Fair Value	0			5
Forward Contracts, Liability Estimated Fair Value	$ 0			$ 0

Derivative Financial Instrume_8

Derivative Financial Instruments (Schedule of Amounts Related to Interest Rate Derivatives Designated as Hedges of Fair Value) (Detail) - Designated as Hedging Instrument [Member] - Commercial Loan/Lease Interest Rate Swaps [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Interest Income on Loans [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount included in income or expense	$ 0	$ 16	$ (7)
Other Non-Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount included in income or expense	$ 0	$ 0	$ 6

Derivative Financial Instrume_9

Derivative Financial Instruments (Schedule of Amounts Related to Non-Hedging Interest Rate and Commodity Derivatives) (Detail) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Interest Rate Contract [Member] | Other Non-Interest Income [Member]
Other Non Interest Income Non Hedging Interest Rate Derivatives [Line Items]
Amount included in income or expense	$ 4,304	$ 6,982	$ 1,742
Interest Rate Contract [Member] | Other Non-Interest Expense [Member]
Other Non Interest Income Non Hedging Interest Rate Derivatives [Line Items]
Amount included in income or expense	3	0	0
Commodity Contract [Member]
Other Non Interest Income Non Hedging Interest Rate Derivatives [Line Items]
Amount included in income or expense	2,183	1,889	2,297
Foreign Exchange Contract [Member]
Other Non Interest Income Non Hedging Interest Rate Derivatives [Line Items]
Amount included in income or expense	$ 11	$ 30	$ 63

Balance Sheet Offsetting - Fina

Balance Sheet Offsetting - Financial Instruments Eligible for Offset Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Gross Amount Recognized, Derivative, Financial Assets	$ 101,329	$ 119,723
Gross Amount Offset, Derivatives, Financial Assets	0	0
Net Amount Recognized, Derivative, Financial Assets	101,329	119,723
Gross Amount Recognized, Resell Agreements, Financial Assets	9,650	84,650
Gross Amount Offset, Resell Agreements, Financial Assets	0	0
Net Amount Recognized, Resell Agreements, Financial Assets	9,650	84,650
Gross Amount Recognized, Financial Assets	110,979	204,373
Gross Amount Offset, Financial Assets	0	0
Net Amount Recognized, Financial Assets	110,979	204,373
Gross Amount Recognized, Derivative, Financial Liabilities	26,019	41,311
Gross Amount Offset, Derivative, Financial Liabilities	0	0
Net Amount Recognized, Derivative, Financial Liabilities	26,019	41,311
Gross Amount Recognized, Repurchase Agreements, Financial Liabilities	4,342,941	4,127,188
Gross Amount Offset, Repurchase Agreements, Financial Liabilities	0	0
Net Amount Recognized, Repurchase Agreements, Financial Liabilities	4,342,941	4,127,188
Gross Amount Recognized, Financial Liabilities	4,368,960	4,168,499
Gross Amount Offset, Financial Liabilities	0	0
Net Amount Recognized, Financial Liabilities	4,368,960	4,168,499
Loan Lease Interest Rate Swaps And Caps [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Gross Amount Recognized, Derivative, Financial Assets	70,054	70,233
Gross Amount Offset, Derivatives, Financial Assets	0	0
Net Amount Recognized, Derivative, Financial Assets	70,054	70,233
Commodity Swaps And Options [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Gross Amount Recognized, Derivative, Financial Assets	31,275	49,489
Gross Amount Offset, Derivatives, Financial Assets	0	0
Net Amount Recognized, Derivative, Financial Assets	31,275	49,489
Gross Amount Recognized, Derivative, Financial Liabilities	16,951	20,999
Gross Amount Offset, Derivative, Financial Liabilities	0	0
Net Amount Recognized, Derivative, Financial Liabilities	16,951	20,999
Foreign Currency Forward Contracts [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Gross Amount Recognized, Derivative, Financial Assets		1
Gross Amount Offset, Derivatives, Financial Assets		0
Net Amount Recognized, Derivative, Financial Assets		1
Gross Amount Recognized, Derivative, Financial Liabilities		19
Gross Amount Offset, Derivative, Financial Liabilities		0
Net Amount Recognized, Derivative, Financial Liabilities		19
Loan Lease Interest Rate Swaps [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Gross Amount Recognized, Derivative, Financial Liabilities	9,068	20,293
Gross Amount Offset, Derivative, Financial Liabilities	0	0
Net Amount Recognized, Derivative, Financial Liabilities	$ 9,068	$ 20,293

Balance Sheet Offsetting - Fi_2

Balance Sheet Offsetting - Financial Instruments Derivative Assets Liabilities and Resell Agreements Net of Amount Not Offset (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Net Amount Recognized, Derivatives, Financial Assets	$ 101,329	$ 119,723
Gross Amounts Not Offset, Financial Instruments, Total Derivatives, Financial Assets	(25,714)	(32,431)
Gross Amounts Not Offset, Collateral, Derivatives, Financial Assets	(74,157)	(84,839)
Net Amount, Derivatives, Financial Assets	1,458	2,453
Net Amount Recognized, Resell Agreements, Financial Assets	9,650	84,650
Gross Amounts Not Offset, Financial Instruments, Resell Agreements, Financial Assets	0	0
Gross Amounts Not Offset, Collateral, Resell Agreements, Financial Assets	(9,650)	(84,650)
Net Amount, Resell Agreements, Financial Assets	0	0
Net Amount Recognized, Total Financial Assets	110,979	204,373
Gross Amounts Not Offset, Collateral, Financial Assets	(83,807)	(169,489)
Net Amount, Financial Assets	1,458	2,453
Net Amount Recognized, Derivatives, Financial Liabilities	26,019	41,311
Gross Amounts Not Offset, Financial Instruments, Total Derivatives, Financial Liabilities	(25,714)	(32,431)
Gross Amounts Not offset, Collateral, Derivatives, Financial Liabilities	(305)	(8,580)
Net Amount, Derivatives, Financial Liabilities	0	300
Net Amount Recognized, Repurchase Agreements, Financial Liabilities	4,342,941	4,127,188
Gross Amounts Not Offset, Financial Instruments, Repurchase Agreements, Financial Liabilities	0	0
Gross Amounts Not Offset, Collateral, Repurchase Agreements, Financial Liabilities	(4,342,941)	(4,127,188)
Net Amount, Repurchase Agreements, Financial Liabilities	0	0
Net Amount Recognized, Financial Liabilities	4,368,960	4,168,499
Gross Amounts Not Offset, Collateral, Financial Liabilities	(4,343,246)	(4,135,768)
Net Amount, Financial Liabilities	0	300
Counterparty H
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Net Amount Recognized, Derivatives, Financial Assets	36,286	36,551
Gross Amounts Not Offset, Financial Instruments, Total Derivatives, Financial Assets	(10,129)	(8,870)
Gross Amounts Not Offset, Collateral, Derivatives, Financial Assets	(26,157)	(27,170)
Net Amount, Derivatives, Financial Assets	0	511
Net Amount Recognized, Derivatives, Financial Liabilities	10,129	8,870
Gross Amounts Not Offset, Financial Instruments, Total Derivatives, Financial Liabilities	(10,129)	(8,870)
Gross Amounts Not offset, Collateral, Derivatives, Financial Liabilities	0	0
Net Amount, Derivatives, Financial Liabilities	0	0
Counterparty F
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Net Amount Recognized, Derivatives, Financial Assets	15,505	31,202
Gross Amounts Not Offset, Financial Instruments, Total Derivatives, Financial Assets	(2,322)	(7,444)
Gross Amounts Not Offset, Collateral, Derivatives, Financial Assets	(11,759)	(22,954)
Net Amount, Derivatives, Financial Assets	1,424	804
Net Amount Recognized, Derivatives, Financial Liabilities	2,322	7,444
Gross Amounts Not Offset, Financial Instruments, Total Derivatives, Financial Liabilities	(2,322)	(7,444)
Gross Amounts Not offset, Collateral, Derivatives, Financial Liabilities	0	0
Net Amount, Derivatives, Financial Liabilities	0	0
Counterparty B
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Net Amount Recognized, Derivatives, Financial Assets	22,338	23,829
Gross Amounts Not Offset, Financial Instruments, Total Derivatives, Financial Assets	(4,522)	(5,151)
Gross Amounts Not Offset, Collateral, Derivatives, Financial Assets	(17,816)	(18,472)
Net Amount, Derivatives, Financial Assets	0	206
Net Amount Recognized, Derivatives, Financial Liabilities	4,522	5,151
Gross Amounts Not Offset, Financial Instruments, Total Derivatives, Financial Liabilities	(4,522)	(5,151)
Gross Amounts Not offset, Collateral, Derivatives, Financial Liabilities	0	0
Net Amount, Derivatives, Financial Liabilities	0	0
Counterparty E
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Net Amount Recognized, Derivatives, Financial Assets	14,219	13,271
Gross Amounts Not Offset, Financial Instruments, Total Derivatives, Financial Assets	(2,109)	(4,548)
Gross Amounts Not Offset, Collateral, Derivatives, Financial Assets	(12,100)	(8,723)
Net Amount, Derivatives, Financial Assets	10	0
Net Amount Recognized, Derivatives, Financial Liabilities	2,109	4,548
Gross Amounts Not Offset, Financial Instruments, Total Derivatives, Financial Liabilities	(2,109)	(4,548)
Gross Amounts Not offset, Collateral, Derivatives, Financial Liabilities	0	0
Net Amount, Derivatives, Financial Liabilities	0	0
Other Counterparties [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Net Amount Recognized, Derivatives, Financial Assets	12,981	14,870
Gross Amounts Not Offset, Financial Instruments, Total Derivatives, Financial Assets	(6,632)	(6,418)
Gross Amounts Not Offset, Collateral, Derivatives, Financial Assets	(6,325)	(7,520)
Net Amount, Derivatives, Financial Assets	24	932
Net Amount Recognized, Derivatives, Financial Liabilities	6,937	15,298
Gross Amounts Not Offset, Financial Instruments, Total Derivatives, Financial Liabilities	(6,632)	(6,418)
Gross Amounts Not offset, Collateral, Derivatives, Financial Liabilities	(305)	(8,580)
Net Amount, Derivatives, Financial Liabilities	$ 0	$ 300

Balance Sheet Offsetting Bala_2

Balance Sheet Offsetting Balance Sheet Offsetting - Remaining Contractual Maturity of the Securities Sold Under Agreement to Repurchase (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Remaining Contractual Maturity of the Securities Sold Under Agreement to Repurchase [Line Items]
Remaining contractual maturity of the agreements overnight and continuous	$ 4,342,941	$ 4,127,188
Remaining contractual maturity of the agreements up to 30 Days	0	0
Remaining contractual maturity of the agreements 30 to 90 Days	0	0
Remaining contractual maturity of the agreements greater than 90 Days	0	0
Remaining contractual maturity of the agreements total	4,342,941	4,127,188
Securities Sold under Agreements to Repurchase, Gross	4,342,941	4,127,188
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities	0	0
US Treasury [Member]
Remaining Contractual Maturity of the Securities Sold Under Agreement to Repurchase [Line Items]
Remaining contractual maturity of the agreements overnight and continuous	2,170,482	3,300,662
Remaining contractual maturity of the agreements up to 30 Days	0	0
Remaining contractual maturity of the agreements 30 to 90 Days	0	0
Remaining contractual maturity of the agreements greater than 90 Days	0	0
Remaining contractual maturity of the agreements total	2,170,482	3,300,662
Residential Mortgage Backed Securities [Member]
Remaining Contractual Maturity of the Securities Sold Under Agreement to Repurchase [Line Items]
Remaining contractual maturity of the agreements overnight and continuous	2,172,459	826,526
Remaining contractual maturity of the agreements up to 30 Days	0	0
Remaining contractual maturity of the agreements 30 to 90 Days	0	0
Remaining contractual maturity of the agreements greater than 90 Days	0	0
Remaining contractual maturity of the agreements total	$ 2,172,459	$ 826,526

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments using fair value measurement option	$ 0	$ 0

Fair Value Measurements (Financ

Fair Value Measurements (Financial Assets and Financial Liabilities Measured at Fair Value on Recurring Basis) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at estimated fair value	$ 15,043,625	$ 16,578,371
Trading account securities	33,910	31,717
Derivative assets:	101,329	119,723
Derivative liabilities:	26,019	41,311
Interest Rate Swaps Caps And Floors [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	79,122	90,715
Derivative liabilities:	79,122	90,525
Commodity Swaps And Options [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	48,503	70,710
Derivative liabilities:	47,304	69,447
Foreign Exchange Forward [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	0	22
Derivative liabilities:	0	19
US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at estimated fair value	3,442,320	4,927,589
Trading account securities	33,910	30,265
Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at estimated fair value	6,997,902	6,596,682
US States and Political Subdivisions Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at estimated fair value	4,560,224	5,011,331
Trading account securities	0	1,452
Other Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at estimated fair value	43,179	42,769
Level 1 [Member] | US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at estimated fair value	3,442,320	4,927,589
Trading account securities	33,910	30,265
Level 2 [Member] | Interest Rate Swaps Caps And Floors [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	79,122	90,715
Derivative liabilities:	79,122	90,525
Level 2 [Member] | Commodity Swaps And Options [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	48,503	70,710
Derivative liabilities:	47,304	69,447
Level 2 [Member] | Foreign Exchange Forward [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	0	22
Derivative liabilities:	0	19
Level 2 [Member] | Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at estimated fair value	6,997,902	6,596,682
Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at estimated fair value	4,560,224	5,011,331
Trading account securities	0	1,452
Level 2 [Member] | Other Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at estimated fair value	43,179	42,769
US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at estimated fair value	3,442,320	4,927,589
Trading account securities	33,910	30,265
Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at estimated fair value	6,997,902	6,596,682
US States and Political Subdivisions Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at estimated fair value	4,560,224	5,011,331
Trading account securities	0	1,452
Other Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at estimated fair value	$ 43,179	$ 42,769

Fair Value Measurements (Impair

Fair Value Measurements (Impaired Loans Remeasured and Reported at Fair Value of Underlying Collateral) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value before allocations	$ 4,982	$ 19,719	$ 6,237
Specific (allocations) reversals of prior allocations	(650)	(3,391)	(1,480)
Fair value	4,332	16,328	4,757
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Reversal of specific valuation allowance allocations			625
Carrying value before allocations	37,082	15,465	8,156
Specific (allocations) reversals of prior allocations	(10,987)	(2,344)
Fair value	$ 26,095	$ 13,121	$ 8,781

Fair Value Measurements - Forec

Fair Value Measurements - Foreclosed Assets Remeasured and Reported at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Foreclosed Assets Remeasured at Initial Recognition Carrying Value Of Foreclosed Assets Prior To Remeasurement	$ 19,297	$ 0	$ 239
Foreclosed Assets Remeasured at Initial Recognition Charge Offs Recognized In Allowance For Loan Losses	(3,797)	0	0
Fair Value of Foreclosed Assets Remeasured at Initial Recognition	$ 15,500	$ 0	$ 239

Fair Value Measurements (Estima

Fair Value Measurements (Estimated Fair Values of Financial Instruments) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total cash and cash equivalents	$ 10,234,258	$ 8,687,276	$ 12,028,132	$ 16,583,000
Securities held to maturity	3,533,775	3,619,428
Deposits	42,722,748	41,920,568
Federal funds purchased	21,975	14,200
Repurchase agreements	4,342,941	4,127,188
Junior subordinated deferrable interest debentures	123,184	123,127
Subordinated notes	99,648	99,491
Net loans	20,484,662	18,578,255
Carrying Amount [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total cash and cash equivalents	10,234,258	8,687,276
Securities held to maturity	3,533,775	3,619,428
Accrued interest receivable	236,591	251,385
Deposits	42,722,748	41,920,568
Federal funds purchased	21,975	14,200
Repurchase agreements	4,342,941	4,127,188
Junior subordinated deferrable interest debentures	123,184	123,127
Subordinated notes	99,648	99,491
Accrued interest payable	58,870	61,222
Carrying Amount [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net loans	20,484,662	18,578,255
Estimated Fair Value [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total cash and cash equivalents	10,234,258	8,687,276
Securities held to maturity	3,360,546	3,532,044
Accrued interest receivable	236,591	251,385
Deposits	42,712,907	41,903,580
Federal funds purchased	21,975	14,200
Repurchase agreements	4,342,941	4,127,188
Junior subordinated deferrable interest debentures	123,712	123,712
Subordinated notes	98,453	96,071
Accrued interest payable	58,870	61,222
Estimated Fair Value [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net loans	$ 20,066,512	$ 18,117,369

Operating Segments Operating Se

Operating Segments Operating Segments - Additional Information (Details) $ in Billions	12 Months Ended
	Dec. 31, 2024 USD ($) Segment	Dec. 31, 2023 USD ($) Segment	Dec. 31, 2022 USD ($) Segment
Segment Reporting Information [Line Items]
Number of operating segments | Segment	2	2	2
Frost Wealth Advisors [Member]
Segment Reporting Information [Line Items]
Fair value of off-balance sheet managed and custody assets | $	$ 51.4	$ 47.2	$ 42.9

Operating Segments (Summary of

Operating Segments (Summary of Operating Results by Segment) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Interest income	$ 2,390,637	$ 2,217,716	$ 1,475,721
Net interest income (expense)	1,604,612	1,558,664	1,291,283
Credit loss expense	64,985	46,171	3,000
Net interest income after credit loss expense	1,539,627	1,512,493	1,288,283
Trust and investment management fees	165,270	153,315	154,679
Service charges on deposit accounts	106,230	93,504	91,891
Insurance commissions and fees	61,269	58,271	53,210
Interchange and card transaction fees	21,017	19,419	18,231
Other charges, commissions and fees	53,348	49,026	41,590
Net gain (loss) on securities transactions	(96)	66	0
Other	52,060	54,941	45,217
Total non-interest income	459,098	428,542	404,818
Salaries and wages	621,394	547,718	492,096
Employee benefits	122,446	115,306	88,608
Net occupancy	128,751	124,396	112,495
Technology, furniture and equipment	148,487	135,286	120,771
Deposit insurance	37,269	76,589	15,603
Other	244,411	229,367	194,701
Total non-interest expense	1,302,758	1,228,662	1,024,274
Income (loss) before income taxes	695,967	712,373	668,827
Income tax expense (benefit)	113,425	114,400	89,677
Net income (loss)	582,542	597,973	579,150
Preferred stock dividends	6,675	6,675	6,675
Net income (loss) available to common shareholders	575,867	591,298	572,475
Revenues from (expenses to) external customers	2,063,710	1,987,206	1,696,101
Average assets (in millions)	49,694,000	49,604,000	51,513,000
Banking [Member]
Segment Reporting Information [Line Items]
Interest income	2,382,675	2,209,659	1,470,947
Interest expense	772,075	647,218	175,480
Net interest income (expense)	1,610,600	1,562,441	1,295,467
Credit loss expense	64,985	46,171	3,000
Net interest income after credit loss expense	1,545,615	1,516,270	1,292,467
Trust and investment management fees	0	0	0
Service charges on deposit accounts	106,217	93,478	91,851
Insurance commissions and fees	61,269	58,271	53,210
Interchange and card transaction fees	21,017	19,419	18,231
Other charges, commissions and fees	30,626	30,217	24,520
Net gain (loss) on securities transactions	(96)	66	0
Other	45,790	49,868	43,064
Total non-interest income	264,823	251,319	230,876
Salaries and wages	544,843	480,083	430,660
Employee benefits	109,431	103,427	78,178
Net occupancy	115,136	109,953	98,916
Technology, furniture and equipment	142,517	129,042	115,257
Deposit insurance	37,203	76,535	15,569
Other	189,700	178,784	147,841
Total non-interest expense	1,138,830	1,077,824	886,421
Income (loss) before income taxes	671,608	689,765	636,922
Income tax expense (benefit)	110,524	111,145	85,127
Net income (loss)	561,084	578,620	551,795
Preferred stock dividends	0	0	0
Net income (loss) available to common shareholders	561,084	578,620	551,795
Revenues from (expenses to) external customers	1,875,423	1,813,760	1,526,343
Average assets (in millions)	49,621,000	49,536,000	51,448,000
Frost Wealth Advisors [Member]
Segment Reporting Information [Line Items]
Interest income	7,962	8,057	4,774
Interest expense	421	437	129
Net interest income (expense)	7,541	7,620	4,645
Credit loss expense	0	0	0
Net interest income after credit loss expense	7,541	7,620	4,645
Trust and investment management fees	167,448	155,278	156,751
Service charges on deposit accounts	13	26	40
Insurance commissions and fees	0	0	0
Interchange and card transaction fees	0	0	0
Other charges, commissions and fees	22,717	18,809	17,070
Net gain (loss) on securities transactions	0	0	0
Other	6,011	4,793	2,013
Total non-interest income	196,189	178,906	175,874
Salaries and wages	74,928	66,070	59,988
Employee benefits	12,911	11,776	10,273
Net occupancy	13,615	14,443	13,579
Technology, furniture and equipment	5,764	6,054	5,341
Deposit insurance	66	54	34
Other	49,790	46,081	42,794
Total non-interest expense	157,074	144,478	132,009
Income (loss) before income taxes	46,656	42,048	48,510
Income tax expense (benefit)	9,798	8,830	10,187
Net income (loss)	36,858	33,218	38,323
Preferred stock dividends	0	0	0
Net income (loss) available to common shareholders	36,858	33,218	38,323
Revenues from (expenses to) external customers	203,730	186,526	180,519
Average assets (in millions)	64,000	59,000	57,000
Non-Banks [Member]
Segment Reporting Information [Line Items]
Interest income	0	0	0
Interest expense	13,529	11,397	8,829
Net interest income (expense)	(13,529)	(11,397)	(8,829)
Credit loss expense	0	0	0
Net interest income after credit loss expense	(13,529)	(11,397)	(8,829)
Trust and investment management fees	(2,178)	(1,963)	(2,072)
Service charges on deposit accounts	0	0	0
Insurance commissions and fees	0	0	0
Interchange and card transaction fees	0	0	0
Other charges, commissions and fees	5	0	0
Net gain (loss) on securities transactions	0	0	0
Other	259	280	140
Total non-interest income	(1,914)	(1,683)	(1,932)
Salaries and wages	1,623	1,565	1,448
Employee benefits	104	103	157
Net occupancy	0	0	0
Technology, furniture and equipment	206	190	173
Deposit insurance	0	0	0
Other	4,921	4,502	4,066
Total non-interest expense	6,854	6,360	5,844
Income (loss) before income taxes	(22,297)	(19,440)	(16,605)
Income tax expense (benefit)	(6,897)	(5,575)	(5,637)
Net income (loss)	(15,400)	(13,865)	(10,968)
Preferred stock dividends	6,675	6,675	6,675
Net income (loss) available to common shareholders	(22,075)	(20,540)	(17,643)
Revenues from (expenses to) external customers	(15,443)	(13,080)	(10,761)
Average assets (in millions)	$ 9,000	$ 9,000	$ 8,000

Condensed Financial Statement_3

Condensed Financial Statements of Parent Company (Schedule of Condensed Balance Sheets) (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Condensed Financial Statements, Captions [Line Items]
Cash	$ 722,906	$ 617,569
Total cash and cash equivalents	10,234,258	8,687,276	$ 12,028,132	$ 16,583,000
Total assets	52,520,259	50,845,038
Junior subordinated deferrable interest debentures, net of unamortized issuance costs	123,184	123,127
Subordinated notes, net of unamortized issuance costs	99,648	99,491
Accrued interest payable and other liabilities	1,311,175	844,017
Total liabilities	48,621,671	47,128,591
Shareholders’ Equity	3,898,588	3,716,447	3,137,228	4,439,555
Total liabilities and shareholders’ equity	52,520,259	50,845,038
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Cash	334,512	350,525
Total cash and cash equivalents	334,512	350,525	$ 311,944	$ 471,875
Investment in subsidiaries	3,828,890	3,625,951
Accrued interest receivable and other assets	1,231	1,233
Total assets	4,164,633	3,977,709
Junior subordinated deferrable interest debentures, net of unamortized issuance costs	123,184	123,127
Subordinated notes, net of unamortized issuance costs	99,648	99,491
Accrued interest payable and other liabilities	43,213	38,644
Total liabilities	266,045	261,262
Shareholders’ Equity	3,898,588	3,716,447
Total liabilities and shareholders’ equity	$ 4,164,633	$ 3,977,709

Condensed Financial Statement_4

Condensed Financial Statements of Parent Company (Schedule of Condensed Statements of Income) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Condensed Financial Statements, Captions [Line Items]
Interest income	$ 2,390,637	$ 2,217,716	$ 1,475,721
Other	244,411	229,367	194,701
Income before income taxes and equity in undistributed earnings of subsidiaries	695,967	712,373	668,827
Income tax benefit	(113,425)	(114,400)	(89,677)
Net income (loss)	582,542	597,973	579,150
Preferred stock dividends	6,675	6,675	6,675
Net income (loss) available to common shareholders	575,867	591,298	572,475
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Dividend income paid by Frost Bank	262,214	279,679	51,711
Dividend income paid by non-banks	268	255	109
Interest and other income	0	1,929	0
Interest income	262,482	281,863	51,820
Interest expense	13,529	13,304	8,829
Salaries and employee benefits	1,727	1,668	1,605
Other	7,304	6,653	6,316
Total expenses	22,560	21,625	16,750
Income before income taxes and equity in undistributed earnings of subsidiaries	239,922	260,238	35,070
Income tax benefit	6,896	5,974	5,641
Equity in undistributed earnings of subsidiaries	335,724	331,761	538,439
Net income (loss)	582,542	597,973	579,150
Preferred stock dividends	6,675	6,675	6,675
Net income (loss) available to common shareholders	$ 575,867	$ 591,298	$ 572,475

Condensed Financial Statement_5

Condensed Financial Statements of Parent Company (Schedule of Condensed Statements of Cash Flows) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Condensed Financial Statements, Captions [Line Items]
Net income (loss)	$ 582,542	$ 597,973	$ 579,150
Stock-based compensation	19,763	24,590	18,322
Net tax benefit from stock-based compensation	3,795	894	4,602
Net cash provided by (used in) operating activities	989,532	478,845	722,582
Net cash provided by (used in) investing activities	(180,879)	(942,751)	(8,277,330)
Proceeds from stock option exercises	22,643	9,299	16,659
Purchase of treasury stock	(60,901)	(42,720)	(4,391)
Cash dividends paid on preferred stock	(6,675)	(6,675)	(6,675)
Cash dividends paid on common stock	(242,446)	(232,323)	(209,780)
Net cash provided by (used in) financing activities	738,329	(2,876,950)	2,999,880
Net change in cash and cash equivalents	1,546,982	(3,340,856)	(4,554,868)
Cash and cash equivalents at beginning of year	8,687,276	12,028,132	16,583,000
Cash and cash equivalents at end of year	10,234,258	8,687,276	12,028,132
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net income (loss)	582,542	597,973	579,150
Equity in undistributed earnings of subsidiaries	(335,724)	(331,761)	(538,439)
Stock-based compensation	934	880	720
Net tax benefit from stock-based compensation	463	331	472
Net change in other assets and other liabilities	4,322	19,867	(15,249)
Net cash provided by (used in) operating activities	252,537	287,290	26,654
Net cash provided by (used in) investing activities	0	0	0
Proceeds from stock option exercises	22,643	9,299	16,659
Proceeds from stock-based compensation activities of subsidiaries	18,829	23,710	17,602
Purchase of treasury stock	(60,901)	(42,720)	(4,391)
Cash dividends paid on preferred stock	(6,675)	(6,675)	(6,675)
Cash dividends paid on common stock	(242,446)	(232,323)	(209,780)
Net cash provided by (used in) financing activities	(268,550)	(248,709)	(186,585)
Net change in cash and cash equivalents	(16,013)	38,581	(159,931)
Cash and cash equivalents at beginning of year	350,525	311,944	471,875
Cash and cash equivalents at end of year	$ 334,512	$ 350,525	$ 311,944