Saia (SAIA) 10-K 24 Feb 25 2024 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2024	Feb. 18, 2025	Jun. 30, 2024
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	FY
Entity Registrant Name	Saia, Inc.
Entity Central Index Key	0001177702
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		26,628,578
Entity Public Float			$ 12,611,329,837
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Interactive Data Current	Yes
Entity File Number	0-49983
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	48-1229851
Document Annual Report	true
Document Transition Report	false
Entity Address, Address Line One	11465 Johns Creek Parkway
Entity Address, Address Line Two	Suite 400
Entity Address, City or Town	Johns Creek
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30097
City Area Code	770
Local Phone Number	232-5067
Title of each class	Common Stock, par value $.001 per share
Security Exchange Name	NASDAQ
Trading Symbol	SAIA
ICFR Auditor Attestation Flag	true
Auditor Name	KPMG LLP
Auditor Location	Atlanta, Georgia, United States
Auditor Firm ID	185
Documents Incorporated by Reference	Portions of the definitive Proxy Statement to be filed within 120 days of December 31, 2024, pursuant to Regulation 14A under the Securities Exchange Act of 1934 for the Annual Meeting of Stockholders to be held April 24, 2025, have been incorporated by reference into Part III of this Form 10-K.
Auditor Opinion [Text Block]	We have audited the accompanying consolidated balance sheets of Saia, Inc. and subsidiaries (the Company) as of December 31, 2024 and 2023, the related consolidated statements of operations, stockholders’ equity, and cash flows for each of the years in the three-year period ended December 31, 2024, and the related notes (collectively, the consolidated financial statements). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2024 and 2023, and the results of its operations and its cash flows for each of the years in the three-year period ended December 31, 2024, in conformity with U.S. generally accepted accounting principles. We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company’s internal control over financial reporting as of December 31, 2024, based on criteria established in Internal Control – Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission, and our report dated February 24, 2025 expressed an unqualified opinion on the effectiveness of the Company’s internal control over financial reporting.
Document Financial Statement Error Correction [Flag]	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Current Assets:
Cash and cash equivalents	$ 19,473	$ 296,215
Accounts receivable, less allowances of $4,224 in 2024 and $4,427 in 2023	322,991	311,742
Prepaid expenses	35,497	32,648
Income tax receivable	44,107	1,005
Other current assets	13,701	7,084
Total current assets	435,769	648,694
Property and Equipment, at cost	3,790,069	2,881,800
Less-accumulated depreciation and amortization	1,233,134	1,118,492
Net property and equipment	2,556,935	1,763,308
Operating Lease Right-of-Use Assets	126,828	118,734
Goodwill and Identifiable Intangibles, net	16,442	17,296
Other Noncurrent Assets	30,883	35,533
Total assets	3,166,857	2,583,565
Current Liabilities:
Accounts payable	114,560	141,877
Wages, vacation and employees’ benefits	49,953	75,514
Claims and insurance accruals	43,126	41,641
Other current liabilities	38,036	27,094
Current portion of long-term debt	5,313	10,173
Current portion of operating lease liability	27,372	25,757
Total current liabilities	278,360	322,056
Other Liabilities:
Long-term debt, less current portion	194,981	6,315
Operating lease liability, less current portion	96,798	96,462
Deferred income taxes	219,062	155,841
Claims, insurance and other	66,385	61,397
Total other liabilities	577,226	320,015
Commitments and Contingencies (Note 3)	0	0
Stockholders’ Equity:
Preferred stock, $0.001 par value, 50,000 shares authorized, none issued and outstanding	0	0
Common stock, $0.001 par value, 100,000,000 shares authorized, 26,549,512 and 26,4549,372 shares issued and outstanding at December 31, 2024 and 2023, respectively	27	27
Additional paid-in-capital	295,106	285,092
Deferred compensation trust, 70,100 and 69,672 shares of common stock at cost at December 31, 2024 and 2023, respectively	(7,981)	(5,679)
Retained earnings	2,024,119	1,662,054
Total stockholders’ equity	2,311,271	1,941,494
Total liabilities and stockholders’ equity	$ 3,166,857	$ 2,583,565

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Allowance of accounts receivable	$ 4,224	$ 4,427
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	50,000	50,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	26,598,512	26,549,372
Common stock, shares outstanding	26,598,512	26,549,372
Deferred compensation trust	70,100	69,672

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Operating Revenue	$ 3,209,074	$ 2,881,433	$ 2,792,057
Operating Expenses:
Salaries, wages and employees’ benefits	1,487,847	1,301,280	1,169,539
Purchased transportation	237,306	238,688	315,896
Fuel, operating expenses and supplies	629,402	563,688	558,456
Operating taxes and licenses	80,128	69,542	63,824
Claims and insurance	77,649	67,984	56,601
Depreciation and amortization	210,105	178,845	157,203
Operating losses, net	4,477	910	50
Total operating expenses	2,726,914	2,420,937	2,321,569
Operating Income	482,160	460,496	470,488
Non-operating (Income) Expenses:
Interest expense	8,930	2,535	2,611
Interest income	(1,049)	(6,208)	(217)
Other, net	(1,729)	(2,058)	46
Non-operating (income) expenses, net	6,152	(5,731)	2,440
Income Before Income Taxes	476,008	466,227	468,048
Income Tax Expense	113,943	111,370	110,626
Net Income	$ 362,065	$ 354,857	$ 357,422
Weighted average common shares outstanding – basic	26,689	26,632	26,520
Weighted average common shares outstanding – diluted	26,802	26,763	26,674
Basic Earnings Per Share	$ 13.57	$ 13.32	$ 13.48
Diluted Earnings Per Share	$ 13.51	$ 13.26	$ 13.40

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Deferred Compensation Trust [Member]	Retained Earnings [Member]
Beginning Balance at Dec. 31, 2021	$ 1,220,333	$ 26	$ 274,633	$ (4,101)	$ 949,775
Beginning Balance, Shares at Dec. 31, 2021		26,337,000
Stock compensation, including options and long-term incentives	7,657		7,657
Director deferred share activity	1,170		1,170
Director deferred share activity , Shares		2,000
Exercise of stock options less shares withheld for taxes	4,511		4,511
Exercise of stock options less shares withheld for taxes, Shares		62,000
Shares issued for long-term incentive awards, net of shares withheld for taxes, Shares		63,000
Shares issued for long-term incentive awards, net of shares withheld for taxes	(11,752)		(11,752)
Purchase of shares by Deferred Compensation Trust			3,254	(3,254)
Sale of shares by Deferred Compensation Trust			(2,107)	2,107
Net Income (Loss)	357,422				357,422
Ending Balance at Dec. 31, 2022	1,579,341	$ 26	277,366	(5,248)	1,307,197
Ending Balance, Shares at Dec. 31, 2022		26,464,000
Stock compensation, including options and long-term incentives	10,219		10,219
Director deferred share activity	1,417		1,417
Director deferred share activity , Shares		2,000
Exercise of stock options less shares withheld for taxes	4,875		4,875
Exercise of stock options less shares withheld for taxes, Shares		35,000
Shares issued for long-term incentive awards, net of shares withheld for taxes, Shares		48,000
Shares issued for long-term incentive awards, net of shares withheld for taxes	(9,215)	$ 1	(9,216)
Purchase of shares by Deferred Compensation Trust			620	(620)
Sale of shares by Deferred Compensation Trust			(189)	189
Net Income (Loss)	354,857				354,857
Ending Balance at Dec. 31, 2023	1,941,494	$ 27	285,092	(5,679)	1,662,054
Ending Balance, Shares at Dec. 31, 2023		26,549,000
Stock compensation, including options and long-term incentives	12,822		12,822
Director deferred share activity	1,423		1,423
Director deferred share activity , Shares		2,000
Exercise of stock options less shares withheld for taxes	$ 2,574		2,574
Exercise of stock options less shares withheld for taxes, Shares	20,086	20,000
Shares issued for long-term incentive awards, net of shares withheld for taxes, Shares		28,000
Shares issued for long-term incentive awards, net of shares withheld for taxes	$ (9,107)		(9,107)
Purchase of shares by Deferred Compensation Trust			3,019	(3,019)
Sale of shares by Deferred Compensation Trust			(717)	717
Net Income (Loss)	362,065				362,065
Ending Balance at Dec. 31, 2024	$ 2,311,271	$ 27	$ 295,106	$ (7,981)	$ 2,024,119
Ending Balance, Shares at Dec. 31, 2024		26,599,000

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	$ 362,065	$ 354,857	$ 357,422
Noncash items included in net income:
Depreciation and amortization	210,105	178,845	157,203
Allowance for credit losses	3,412	1,955	3,074
Deferred income taxes	63,221	10,070	21,634
Loss from property disposals, net	4,477	910	50
Stock-based compensation	14,243	11,636	8,827
Changes in operating assets and liabilities:
Accounts receivable	(14,661)	(23,391)	(16,624)
Accounts payable	(816)	10,752	(9,523)
Change in other assets and liabilities, net	(58,344)	32,311	(49,037)
Net cash provided by operating activities	583,702	577,945	473,026
Investing Activities:
Acquisition of property and equipment	(1,043,557)	(439,879)	(367,429)
Proceeds from disposal of property and equipment	2,694	2,727	1,917
Other	4,999	(11,544)	0
Net cash used in investing activities	(1,035,864)	(448,696)	(365,512)
Financing Activities:
Repayments of revolving credit facility	(1,060,100)	0	(1,000)
Borrowings of revolving credit facility	1,154,100	0	1,000
Borrowings on private shelf agreement	100,000	0	0
Proceeds from stock option exercises	2,574	4,875	4,511
Shares withheld for taxes	(9,107)	(9,216)	(11,752)
Repayment of finance leases	(10,193)	(14,520)	(19,471)
Other financing activity	(1,854)	(1,563)	0
Net cash (used in) provided by financing activities	175,420	(20,424)	(26,712)
Net Increase (Decrease) in Cash and Cash Equivalents	(276,742)	108,825	80,802
Cash and cash equivalents, beginning of year	296,215	187,390	106,588
Cash and cash equivalents, end of year	$ 19,473	$ 296,215	$ 187,390

Cybersecurity Risk Management,

Cybersecurity Risk Management, Strategy, and Governance	12 Months Ended
	Dec. 31, 2024
Cybersecurity Risk Management, Strategy, and Governance [Line Items]
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]	Item 1 C. Cybersecurity Cybersecurity risk management and strategy Saia maintains cybersecurity processes, technologies and controls to help us assess, identify and manage material risks from cybersecurity threats. These processes, technologies and controls are part of Saia’s overall enterprise risk management process. Our cybersecurity program is based on the National Institute of Standards and Technology Cybersecurity Framework and is designed to ensure that our information systems are effective and are prepared for cybersecurity threats, including through regular oversight and mitigation of internal and external threats. We regularly perform evaluations of our information security program and our information technology infrastructure, including through the use of tools and services for network and endpoint monitoring, vulnerability assessments and penetration testing, among other things. We have implemented security monitoring capabilities designed to alert us to suspicious activity and have an incident response program to restore business operations as quickly and as orderly as possible in the event of a cybersecurity incident. Saia contracts with third party firms to evaluate our information security program, for continuous system monitoring and threat detection, to gather insights for identifying and assessing material cybersecurity threats, and for potential mitigation assistance. We consider cybersecurity matters when selecting and overseeing our third party service providers and we administer a standardized information gathering questionnaire to evaluate cybersecurity risk in third parties. We seek to require third parties who could pose significant cybersecurity risk to us to be contractually responsible for the risk and to agree to cybersecurity assessments in connection with new vendor engagements and annually thereafter. Saia has an established cybersecurity and information security awareness training program that includes mandatory annual training and regular communications for our employees regarding cybersecurity threats and methods of mitigation. The annual cybersecurity training consists of threat avoidance when working remote, proper password construction techniques, identifying and reporting suspicious activity, social engineering and insider threats. Additionally, we have implemented a regular phishing assessment that provides feedback and additional training as needed to enhance the annual training program. Our information technology professionals also receive additional training related to their position. There can be no guarantee that our policies and procedures will be effective. Although our risk factors include further detail about the material cybersecurity risks we face, we believe that risks from prior cybersecurity threats, including as a result of any previous cybersecurity incidents, have not materially affected our business to date. We can provide no assurance that there will not be incidents in the future or that they will not materially affect us, including our business strategy, results of operations or financial condition. For more information about the cybersecurity risks we face, see the risk factors entitled “We rely heavily on technology to operate our business and cybersecurity threats or other disruptions to our technology infrastructure could harm our business or reputation” and "We use AI in our business, and its use could result in reputational harm, competitive harm, cybersecurity risks and legal liability, which could have a material adverse effect on our results of operations" in Item 1A. Risk Factors. Governance Management is responsible for the day-to-day assessment and management of cybersecurity risks . Saia’s Director of Information Security and Compliance, who reports to the Executive Vice President and Chief Information Officer, has primary oversight of our cybersecurity risk management and strategy processes. The Director of Information Security and Compliance has served in information security roles since 2001 and led the information security function for a large health care system prior to joining Saia. He has a Bachelor of Science degree in Information Technology with a Concentration in Information Assurance and Security. The Director of Information Security and Compliance assesses our cybersecurity readiness through internal assessment tools as well as third-party control testing, vulnerability assessments and evaluation against industry standards. We maintain compliance structures that are designed to elevate issues relating to cybersecurity to our Director of Information Security and Compliance and to our Executive Vice President and Chief Information Officer. The Board of Directors has oversight responsibility for Saia’s strategic and operational risks. Although the Board has delegated oversight responsibility for certain risks to its committees, the Board has determined that oversight for cybersecurity should remain with the full Board. The Board regularly receives reports from the Executive Vice President and Chief Information Officer concerning the Company’s cybersecurity risk management and strategies and related processes, technologies and controls.
Cybersecurity Risk Management Third Party Engaged [Flag]	true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]	true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]	false
Cybersecurity Risk Board of Directors Oversight [Text Block]	Governance Management is responsible for the day-to-day assessment and management of cybersecurity risks . Saia’s Director of Information Security and Compliance, who reports to the Executive Vice President and Chief Information Officer, has primary oversight of our cybersecurity risk management and strategy processes. The Director of Information Security and Compliance has served in information security roles since 2001 and led the information security function for a large health care system prior to joining Saia. He has a Bachelor of Science degree in Information Technology with a Concentration in Information Assurance and Security. The Director of Information Security and Compliance assesses our cybersecurity readiness through internal assessment tools as well as third-party control testing, vulnerability assessments and evaluation against industry standards. We maintain compliance structures that are designed to elevate issues relating to cybersecurity to our Director of Information Security and Compliance and to our Executive Vice President and Chief Information Officer. The Board of Directors has oversight responsibility for Saia’s strategic and operational risks. Although the Board has delegated oversight responsibility for certain risks to its committees, the Board has determined that oversight for cybersecurity should remain with the full Board. The Board regularly receives reports from the Executive Vice President and Chief Information Officer concerning the Company’s cybersecurity risk management and strategies and related processes, technologies and controls.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]	Management is responsible for the day-to-day assessment and management of cybersecurity risks . Saia’s Director of Information Security and Compliance, who reports to the Executive Vice President and Chief Information Officer, has primary oversight of our cybersecurity risk management and strategy processes. The Director of Information Security and Compliance has served in information security roles since 2001 and led the information security function for a large health care system prior to joining Saia. He has a Bachelor of Science degree in Information Technology with a Concentration in Information Assurance and Security. The Director of Information Security and Compliance assesses our cybersecurity readiness through internal assessment tools as well as third-party control testing, vulnerability assessments and evaluation against industry standards. We maintain compliance structures that are designed to elevate issues relating to cybersecurity to our Director of Information Security and Compliance and to our Executive Vice President and Chief Information Officer.
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]	Management is responsible for the day-to-day assessment and management of cybersecurity risks . Saia’s Director of Information Security and Compliance, who reports to the Executive Vice President and Chief Information Officer, has primary oversight of our cybersecurity risk management and strategy processes.
Cybersecurity Risk Role of Management [Text Block]	Saia’s Director of Information Security and Compliance, who reports to the Executive Vice President and Chief Information Officer, has primary oversight of our cybersecurity risk management and strategy processes. The Director of Information Security and Compliance has served in information security roles since 2001 and led the information security function for a large health care system prior to joining Saia. He has a Bachelor of Science degree in Information Technology with a Concentration in Information Assurance and Security.
Cybersecurity Risk Management Positions or Committees Responsible [Flag]	true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block]	The Director of Information Security and Compliance has served in information security roles since 2001 and led the information security function for a large health care system prior to joining Saia. He has a Bachelor of Science degree in Information Technology with a Concentration in Information Assurance and Security.
Cybersecurity Risk Management Expertise of Management Responsible [Text Block]	The Director of Information Security and Compliance assesses our cybersecurity readiness through internal assessment tools as well as third-party control testing, vulnerability assessments and evaluation against industry standards. We maintain compliance structures that are designed to elevate issues relating to cybersecurity to our Director of Information Security and Compliance and to our Executive Vice President and Chief Information Officer.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]	The Board of Directors has oversight responsibility for Saia’s strategic and operational risks. Although the Board has delegated oversight responsibility for certain risks to its committees, the Board has determined that oversight for cybersecurity should remain with the full Board. The Board regularly receives reports from the Executive Vice President and Chief Information Officer concerning the Company’s cybersecurity risk management and strategies and related processes, technologies and controls.
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]	true

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)	$ 362,065	$ 354,857	$ 357,422

Insider Trading Arrangements

Insider Trading Arrangements	3 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

Description of Business and Sum

Description of Business and Summary of Accounting Policies	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Description of Business and Summary of Accounting Policies	1. Description of Business and Summary of Accounting Policies Description of Business Saia, Inc., and its subsidiaries (Saia or the Company), is headquartered in Johns Creek, Georgia. Saia is a leading, less-than-truckload (LTL) motor carrier with more than 97 % of its revenue derived from transporting LTL shipments for customers. In addition to the core LTL services provided in the United States, the Company also offers customers a wide range of other value-added services, including non-asset truckload, expedited transportation and logistics services across North America. Basis of Presentation The accompanying consolidated financial statements include the accounts of Saia, Inc. and its wholly-owned subsidiaries. All significant intercompany accounts and transactions have been eliminated in the consolidated financial statements. Use of Estimates The preparation of our consolidated financial statements in conformity with U.S. generally accepted accounting principles requires the use of estimates and assumptions that affect the reported amounts of assets and liabilities and the reported amounts of revenues and expenses. Management makes its best estimate of the ultimate outcome for these items based on historical trends and other information available when the financial statements are prepared. Changes in estimates are recognized in accordance with the accounting rules for the estimate, which is typically in the period when new information becomes available to management. Areas where the nature of the estimate makes it reasonably possible that actual results could materially differ from amounts estimated include: revenue reserves; self-insurance accruals; long-term incentive compensation; tax liabilities; loss contingencies; litigation claims; and impairment assessments on long-lived assets and goodwill. Recent Accounting Pronouncements Adopted in 2024 In November 2023, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2023-07, “ Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. ” The standard requires all entities with a single reportable segment to apply all segment disclosure requirements. This standard became effective for annual reporting periods beginning after December 15, 2023 and interim reporting periods beginning after December 15, 2024. The Company adopted the standard on a retrospective basis for the 2024 annual reporting period with the impact limited to incremental disclosures in our consolidated financial statements. Recently Issued Accounting Pronouncements In December 2023, the FASB issued ASU No. 2023-09, “Income Taxes (Topic 740): Improvements to Income Tax Disclosures.” Under this ASU, income tax disclosures are expanded primarily by requiring the disaggregation of the rate reconciliation and income taxes paid disclosures. This standard is effective for annual reporting periods beginning after December 15, 2024. The Company is currently evaluating the impact of this standard on its consolidated financial statements and related disclosures. In November 2024, the FASB issued ASU No. 2024-03, "Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses." Under this ASU, entities are required to disclose additional disaggregated information related to certain expense captions included in the Consolidated Statements of Operations. This standard is effective for annual reporting periods beginning after December 15, 2026 and interim reporting periods beginning after December 15, 2027. The Company is currently evaluating the impact of this standard on its consolidated financial statements and related disclosures. Summary of Accounting Policies Significant accounting policies and practices used in the preparation of the accompanying consolidated financial statements are as follows: Cash and Cash Equivalents: Cash and cash equivalents includes cash on hand and short term marketable securities with original maturities of three months or less. Spare Parts, Fuel and Operating Supplies: Spare parts, fuel and operating supplies on hand are carried at average cost and are included in other current assets on the accompanying consolidated balance sheets. Property and Equipment: Property and equipment are carried at cost less accumulated depreciation. Replacements and improvements that extend the useful life of an asset are capitalized, while repairs and maintenance that do not improve or extend the lives of the respective assets are charged to expense as incurred. The Company evaluates long-lived assets for impairment whenever events or changes in circumstances indicate the carrying value of assets may not be recoverable. Depreciation is computed using the straight-line method, except for tractors (included in revenue equipment) for which the declining-balance method is used. The following service lives are used to compute depreciation: Years Structures 15 to 25 Revenue equipment 6 to 20 Technology equipment and software 3 to 5 Other 3 to 10 At December 31, property and equipment consisted of the following (in thousands): 2024 2023 Land $ 350,593 $ 272,633 Structures 1,238,969 813,146 Revenue equipment 1,810,389 1,470,913 Technology equipment and software 225,504 176,854 Other 164,614 148,254 Total property and equipment, at cost $ 3,790,069 $ 2,881,800 The Company’s investment in technology equipment and software consists primarily of systems to support customer service, maintenance and freight management. Depreciation and amortization expense (including amortization of assets under finance leases) was $ 209.2 million, $ 177.9 million and $ 156.2 million for the years ended December 31, 2024, 2023 and 2022, respectively. The Company periodically evaluates estimated useful lives of property and equipment considering its planned and actual usage, planned and actual maintenance and replacement, and other relevant physical and economic factors that may affect our use of the assets. During the second quarter of 2024, the Company determined that the estimated useful lives of certain of its trailers and dollies should be extended from 14 years to 20 years. This change was recognized prospectively. The changes in estimates resulted in an increase in income from continuing operations of approximately $ 7.7 million (a $ 5.8 mil lion increase in net income) for the year ended December 31, 2024. Claims and Insurance Accruals: The Company maintains a significant amount of insurance coverage with third-party insurance carriers that provides various levels of protection for covered risk exposure, including in the areas of workers’ compensation, bodily injury and property damage, casualty, cargo loss and damage and group health, with coverage limits and retention and deductible amounts that vary based on policy periods and claim type. Claims and insurance accruals related to workers’ compensation, bodily injury and property damage, casualty, cargo loss and damage and group health are established by management based on estimates of losses that the Company will ultimately incur on reported claims and on claims that have been incurred but not yet reported. Accruals are calculated on reported claims based on an evaluation of the nature and severity of the claim, historical loss experience and on legal, economic and other factors. Actuarial analysis is also used in calculating the accruals for workers’ compensation and bodily injury and property damage claims. Income Taxes: Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period enacted. As required by FASB Accounting Standards Codification (ASC) Topic 740, Income Taxes , the Company defines the threshold for recognizing the benefits of tax-filing positions in the financial statements as “more-likely-than-not” to be sustained by the tax authority. Revenue Recognition: The Company’s revenues are derived primarily from the transportation of freight as it satisfies performance obligations that arise from contracts with its customers. The Company’s performance obligations arise when it receives a bill of lading (BOL) to transport a customer's commodities at negotiated prices contained in either a transportation services agreement or a publicly disclosed tariff rate. Once a BOL is received and accepted, a legally-enforceable contract is formed whereby the parties are committed to perform and the rights of the parties, shipping terms and conditions, and payment terms have been identified. Each shipment represents a distinct service that is a separately identified performance obligation. The typical transit time to complete a shipment is from one to five days . Billing for transportation services normally occurs after completion of the service and payment is generally due within 30 days after the invoice date. The Company recognizes revenue related to the Company’s LTL, non-asset truckload and expedited transportation services over the transit time of the shipment as it moves from origin to destination based on the transit status at the end of each reporting period. Key estimates included in the recognition and measurement of revenue and related accounts receivable are as follows: • Revenue associated with shipments in transit is recognized ratably over transit time; and • Adjustments to revenue for billing adjustments and collectability. The portion of the gross invoice related to interline transportation services that involve the services of another party, such as another LTL service provider, is not recorded in the Company’s revenues. Revenue from logistics services is recognized as the services are provided. Credit Risk: The Company routinely grants credit to its customers. The risk of significant loss in trade receivables is substantially mitigated by the Company’s credit evaluation process, short collection terms, low revenue per transaction and services performed for a large number of customers, with no single customer representing more than 5 percent of accounts receivable at year-end. Allowances for potential credit losses are based on historical loss experience, current economic environment, expected trends and customer specific factors. Stock-Based Compensation: The Company has various stock-based compensation plans for its employees and non-employee directors. The Company stock-based compensation includes awards of stock options, restricted stock awards, and stock-based performance unit awards, all of which are accounted for under FASB ASC Topic 718, Compensation-Stock Compensation . Stock options granted to employees are valued using a Black-Scholes-Merton model with the expense amortized over the three-year vesting period. Restricted stock is valued based on the fair market value of the Company's common stock at the date of grant and the expense is amortized over the three to five year vesting period. Stock-based performance unit awards are valued using a Monte Carlo model and the expense is amortized over the three-year vesting period. Intangible Assets: The Company tests goodwill for impairment annually and whenever events or changes in circumstance indicate that impairment may have occurred. The Company first performs a qualitative assessment to determine whether it is necessary to perform a quantitative assessment. The Company is not required to estimate the fair value of a reporting unit unless the Company determines, based on qualitative assessment, that it is more likely than not that its fair value is less than its carrying amount. Purchased intangible assets subject to amortization are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Advertising: The costs of advertising are expensed as incurred. Advertising costs charged to expense were $ 5.0 million, $ 2.9 million, and $ 7.2 million in 2024, 2023 and 2022 , respectively. Financial Instruments: The carrying amounts of financial instruments including cash and cash equivalents, accounts receivable and accounts payable approximated fair value as of December 31, 2024 and 2023, because of the relatively short maturity of these instruments. See Note 2 for fair value disclosures related to debt. Segment Reporting: Saia is comprised of a single reportable segment organized around its transportation services. The segment provides core LTL and a wide range of other value-add transportation services to its customers based on negotiated prices contained in either a transportation services agreement or a publicly disclosed tariff rate. Saia derives revenue primarily in the United States and manages its business activities on a consolidated basis using an integrated transportation network. The chief operating decision maker (CODM) is the Chief Executive Officer who regularly reviews the operating results of the Company's single operating segment at the consolidated company level. The accounting policies of the segment are the same as those described in the summary of significant accounting policies. The CODM assesses performance for the segment and determines how to allocate resources based on Saia's consolidated net income. The CODM uses net income to evaluate income generated from segment assets (return on assets) in deciding whether to reinvest profits into the Company or for other purposes, such as for acquisitions, to repay borrowings or to pay dividends. The CODM also uses net income to monitor budget versus actual results, and in competitive analysis by benchmarking to the Company’s competitors. The competitive analysis along with the monitoring of budgeted versus actual results are used in assessing performance of the Company and in establishing management’s compensation. The measure of segment assets is reported on the balance sheet as total consolidated assets. The following table presents selected financial information with respect to the Company’s single reportable segment (in thousands): For The Years Ended December 31, 2024 2023 2022 Revenue $ 3,209,074 $ 2,881,433 $ 2,792,057 Less: Wages (a) 907,750 767,282 689,342 Salaries (a) 190,393 168,794 149,837 Purchased Transportation 237,306 238,688 315,896 Other Segment items (b) 1,179,631 1,065,270 1,009,337 Depreciation and Amortization 210,105 178,845 157,203 Interest Expense 8,930 2,535 2,611 Interest Income ( 1,049 ) ( 6,208 ) ( 217 ) Income Tax Expense 113,943 111,370 110,626 Segment and Consolidated Net Income $ 362,065 $ 354,857 $ 357,422 (a) Wages includes payroll costs for non-management employees generally paid on an hourly or per-mile basis. Salaries includes payroll costs for exempt employees. (b) Other segment items include employees' benefits, fuel, operating expenses and supplies, operating taxes and licenses and claims and insurance.

Debt and Financing Arrangements

Debt and Financing Arrangements	12 Months Ended
	Dec. 31, 2024
Debt Disclosure [Abstract]
Debt and Financing Arrangements	2. Debt and Financing Arrangements At December 31, debt consisted of the following (in thousands): December 31, 2024 December 31, 2023 Credit Arrangements, described below $ 194,000 $ — Finance Leases, described below 6,294 16,488 Total debt 200,294 16,488 Less: current portion of long-term debt 5,313 10,173 Long-term debt, less current portion $ 194,981 $ 6,315 The Company's liquidity needs arise primarily from capital investment in new equipment, land and structures, information technology and letters of credit and surety bonds required under insurance programs, as well as funding working capital requirements. The Company is party to a credit agreement with a group of banks as well as a private shelf debt agreement to fund capital investments, letters of credit and working capital needs. Credit Arrangements Revolving Credit Facility The Company is a party to an unsecured credit agreement with its banking group (the Revolving Credit Facility). On December 9, 2024, the Company entered into an amendment to the Revolving Credit Facility. The amendment increased commitments under the Revolving Credit Facility by $ 300 million to an aggregate commitment of $ 600 million and expanded the accordion feature, subject to certain conditions and availability of lender commitments, from $ 150 million to $ 300 million. This amendment also extended the maturity date of the Revolving Credit Facility from February 3, 2028, to December 9, 2029. Borrowings under the Revolving Credit Facility bear interest at the Company’s election at a variable rate equal to (a) one, three or six month term SOFR (the forward-looking secured overnight financing rate) plus 0.10 %, or (b) an alternate base rate, in each case plus an applicable margin. Additionally, the amendment adjusts the applicable margin such that the applicable margin is now between 1.25 % and 2.00 % per annum for term SOFR loans and between 0.25 % and 1.00 % per annum for alternate base rate loans, in each case based on the Company’s consolidated net lease adjusted leverage ratio. The amendment also modifies the fees that the Company accrues based on the daily unused portion of the credit facility, which will now range between 0.175 % and 0.30 % based on the Company’s consolidated net lease adjusted leverage ratio. The Revolving Credit Facility contains certain customary representations and warranties, affirmative and negative covenants and provisions relating to events of default. Under the Revolving Credit Facility, if an event of default occurs, the banks will be entitled to take various actions, including the acceleration of amounts due. Under the Revolving Credit Facility, the Company is subject to a maximum consolidated net lease adjusted leverage ratio of less than 3.50 to 1.00 with the potential to be temporarily increased in the event the Company makes an acquisition that meets certain criteria. The Company was in compliance with its debt covenants under the Revolving Credit Facility at December 31, 2024 At December 31, 2024, the Company had outstanding borrowings of $ 94.0 million and outstanding letters of credit of $ 32.2 million under the Revolving Credit Facility. At December 31, 2023 , the Company had no outstanding borrowings and outstanding letters of credit of $ 32.1 million under the Revolving Credit Facility. The carrying amount of the Company’s variable rate debt approximates fair value as interest rates approximate the current rates available to the Company. Private Shelf Agreement On November 9, 2023, the Company entered into a $ 350 million uncommitted Private Shelf Agreement (the Shelf Agreement), with PGIM, Inc. (Prudential), and certain affiliates and managed accounts of Prudential (the Note Purchasers) which allows the Company, from time to time, to offer for sale to Prudential and its affiliates, in one or a series of transactions, senior notes of the Company, through November 9, 2026. Pursuant to the Shelf Agreement, on May 1, 2024, the Company issued senior promissory notes (the Initial Notes) in an aggregate principal amount of $ 100 million to the Note Purchasers. The Initial Notes bear interest at 6.09 % per annum and mature on May 1, 2029, unless repaid earlier by the Company. The Initial Notes are senior unsecured obligations and rank pari passu with borrowings under the Revolving Credit Facility or other senior promissory notes issued pursuant to the Shelf Agreement. Additional notes issued under the Shelf Agreement, if any, would bear interest at a rate per annum, and would have such other terms, as would be set forth in a confirmation of acceptance executed by the parties prior to the closing of the applicable sale transaction. The Shelf Agreement requires that the Company maintain a consolidated net lease adjusted leverage ratio of less than 3.50 to 1.00, with limited exceptions. The Shelf Agreement also contains certain customary representations and warranties, affirmative and negative covenants and provisions related to events of default. Upon the occurrence and continuance of an event of default, the holders of notes issued under the Shelf Agreement may require immediate payment of all amounts owing under such notes. The Company was in compliance with its debt covenants under the Shelf Agreement at December 31, 2024. At December 31, 2024 and 2023, the Company had outstanding notes under the Shelf Agreement of $ 100.0 million and $ 0 , respectively. The estimated fair value of these notes approximates book value for each year. Finance Leases The Company is obligated under finance leases with seven-year terms which include obligations collateralized by revenue equipment totaling $ 6.3 million and $ 16.5 million as of December 31, 2024 and 2023, respectively. Amortization of assets held under the finance leases is included in depreciation and amortization expense. The estimated fair value of the finance leases at December 31, 2024 and 2023 is $ 6.3 million and $ 16.1 million , respectively, which is based on current market interest rates for similar types of financial instruments, reflective of Level 2 inputs. Other The Company paid cash for interest of $ 7.7 million, $ 1.6 million, and $ 2.3 million for the years ended December 31, 2024, 2023 and 2022 , respectively.

Commitments, Contingencies and

Commitments, Contingencies and Uncertainties	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments, Contingencies and Uncertainties	3. Commitments, Contingencies and Uncertainties The Company has contractual obligations and commitments in the form of finance leases, operating leases and purchase commitments. At December 31, 2024, the Company was committed under non-cancellable operating lease agreements requiring minimum annual rentals payable as follows (in thousands): Amount 2025 $ 36,094 2026 28,798 2027 25,324 2028 20,381 2029 14,988 Thereafter 21,763 Total $ 147,348 Rent expense was $ 42.5 million, $ 37.2 million, and $ 33.4 million for the years ended December 31, 2024, 2023 and 2022, respectively. Management expects that in the normal course of business, leases will be renewed or replaced as they expire. Finance and operating leases are discussed further in Note 4, "Leases." Purchase commitments related to capital expenditures were $ 27.6 million at December 31, 2024. As of December 31, 2024 and 2023, the Company had $ 24.4 million and $ 50.9 million, respectively, of capital expenditures accrued for in accounts payable. Other The Company is subject to legal proceedings that arise in the ordinary course of its business. Management believes that adequate provisions for resolution of all contingencies, claims and pending litigation have been made for probable and estimable losses and that the ultimate outcome of these actions will not have a material adverse effect on its financial condition but could have a material adverse effect on its results of operations in a given quarter or annual period.

Leases

Leases	12 Months Ended
	Dec. 31, 2024
Leases [Abstract]
Leases	4. Leases The Company’s leases include, but are not limited to, real estate, including terminals and general office buildings, trailers, corporate fleet vehicles and other equipment. Leases with an initial term of 12 months or less are not recorded on the consolidated balance sheet; the Company recognizes lease expense for these leases on a straight-line basis over the lease term. As of December 31, 2024 and 2023, approximately $ 18.2 million and $ 38.6 million , respectively, of finance leased assets, net of amortization, were included in property and equipment . Accumulated amortization for these assets totaled $ 16.2 million and $ 31.2 million as of the same periods ended. A summary of the lease costs for the years ended December 31, 2024 and 2023 follows (in thousands): 2024 2023 Finance lease cost: Amortization of right-of-use assets $ 3,770 $ 5,693 Interest on lease liabilities 426 883 Operating lease cost (includes variable and sublease costs as they are immaterial) 38,755 34,522 Short-term lease cost 15,336 16,303 Total lease cost $ 58,287 $ 57,401 Other Information Right-of-use assets obtained in exchange for new finance lease liabilities — — Right-of-use assets obtained in exchange for new operating lease liabilities 40,540 27,026 The discount rate used in the Company's calculation of its right-of-use assets and corresponding lease liabilities was determined based on the rate implicit in the lease if readily determinable, or its incremental borrowing rate, which approximates the rate at which the Company could borrow, on a collateralized basis, over the term of a lease. Supplemental cash flow and balance sheet information related to leases was as follows (in thousands, except where noted): 2024 2023 Cash paid for amounts included in the measurement of lease liabilities Operating cash outflows from finance leases $ 444 $ 890 Operating cash outflows from operating leases 37,844 35,339 Financing cash outflows from finance leases 10,193 14,520 Weighted-average remaining lease term - finance leases (years) 0.7 1.2 Weighted-average remaining lease term - operating leases (years) 5.2 5.4 Weighted-average discount rate - finance leases 4.1 % 4.0 % Weighted-average discount rate - operating leases 5.5 % 5.4 % As of December 31, 2024, maturities of lease liabilities were as follows (in thousands): Operating Leases Finance Leases Maturity of Lease Liabilities 2025 $ 36,094 $ 5,434 2026 28,798 993 2027 25,324 - 2028 20,381 - 2029 14,988 - Thereafter 21,763 - Total lease payments 147,348 6,427 Less: Interest 23,178 133 Present value of lease liabilities $ 124,170 $ 6,294

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	5. Goodwill and Other Intangible Assets There was no change to the carrying amount of goodwill of $ 12.1 million for fiscal years ending December 31, 2024, 2023 and 2022, respectively. The gross amounts and accumulated amortization of identifiable intangible assets are as follows (in thousands): December 31, 2024 December 31, 2023 Gross Amount Accumulated Amortization Gross Amount Accumulated Amortization Amortizable intangible assets: Customer relationships (useful life of 6 - 15 years) $ 19,000 $ 15,171 $ 19,000 $ 14,417 Trademarks (useful life of 15 years) 1,500 992 1,500 892 Total $ 20,500 $ 16,163 $ 20,500 $ 15,309 Amortization expense for intangible assets was $ 0.9 million for 2024 , $ 0.9 million in 2023 and $ 1.0 million in 2022 . Estimated amortization expense for the next five years is as follows (in thousands): Amount 2025 $ 853 2026 853 2027 853 2028 853 2029 853

Computation of Earnings Per Sha

Computation of Earnings Per Share	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Computation of Earnings Per Share	6. Computation of Earnings Per Share The calculation of basic earnings per common share and diluted earnings per common share is as follows (in thousands except per share amounts): For The Years Ended December 31, 2024 2023 2022 Numerator: Net income $ 362,065 $ 354,857 $ 357,422 Denominator: Denominator for basic earnings per share–weighted 26,689 26,632 26,520 Dilutive effect of share-based awards 113 131 154 Denominator for diluted earnings per share–adjusted 26,802 26,763 26,674 Basic Earnings Per Share $ 13.57 $ 13.32 $ 13.48 Diluted Earnings Per Share $ 13.51 $ 13.26 $ 13.40 In 2024, there were 50 anti-dilutive share-based awards. In 2023, there were 5,790 anti-dilutive share-based awards. In 2022 , there were 22,237 anti-dilutive share-based awards.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Stockholders' Equity	7. Stockholders’ Equity Deferred Compensation Plan The Saia Executive Capital Accumulation Plan (Capital Accumulation Plan) is a nonqualified deferred compensation plan for Saia executives. The Capital Accumulation Plan allows for the plan participants to invest in the Company’s common stock. Elections to invest in the Company’s common stock are irrevocable, and upon distribution, the funds invested in the Company’s common stock are paid out in Company common stock rather than cash. At December 31, 2024 and 2023, the Company’s rabbi trust, which holds the investments for the Capital Accumulation Plan, held 70,100 and 69,672 shares of the Company’s common stock, respectively, all of which were purchased on the open market. The following table summarizes the shares of the Company’s common stock that were purchased and sold by the Company’s rabbi trust (in thousands except share amounts): For The Years Ended December 31, 2024 2023 2022 Shares of common stock purchased 7,310 2,110 12,117 Aggregate purchase price of shares purchased $ 3,019 $ 620 $ 3,254 Shares of common stock sold 6,882 2,420 36,762 Aggregate sale price of shares sold $ 2,929 $ 835 $ 10,370 Company common stock held by the rabbi trust is accounted for within stockholders' equity similar to treasury stock at historical cost with the corresponding deferred compensation obligation also presented within stockholders' equity as additional paid-in capital. Directors’ Deferred Compensation Under the Company’s Directors’ Deferred Fee Plan, non-employee directors may elect to defer all or a portion of their annual fees and retainers. Such deferrals are converted into units equivalent to the value of the Company’s stock. Upon the director’s termination, death or disability, accumulated deferrals are distributed in the form of Company common stock in accordance with elections made by the directors. The Company had 101,951 and 100,110 shares reserved for issuance under the Directors’ Deferred Fee Plan at December 31, 2024 and 2023 , respectively. The shares reserved for issuance under the Directors’ Deferred Fee Plan are treated as common stock in computing basic earnings per share.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	8. Stock-Based Compensation The stockholders of the Company approved the 2018 Omnibus Incentive Plan (the 2018 Omnibus Plan) and the Second Amended and Restated 2011 Omnibus Incentive Plan (the 2011 Omnibus Plan) to allow the Company to issue equity based compensation to help attract and retain executive, managerial, supervisory or professional employees and non-employee directors. The 2018 Omnibus Plan has 1,100,000 shares of common stock reserved. The 2011 Omnibus Plan had a total of 2,350,000 shares of common stock reserved. Following stockholder approval of the 2018 Omnibus Plan, no additional awards have been made under the 2011 Omnibus Plan. The 2018 Omnibus Plan and the 2011 Omnibus Plan provide for the grant or award of stock options; stock appreciation rights; restricted and unrestricted stock; restricted stock units; and performance unit awards. At December 31, 2024 and 2023, 391,089 shares remain reserved and unissued under the provisions of the 2011 Omnibus Plan, a portion of which are allocated to outstanding stock options described below. At December 31, 2024 and 2023, 633,409 and 677,500 shares, respectively, remain reserved and unissued under the provisions of the 2018 Omnibus Plan, a portion of which are allocated to outstanding performance unit awards, outstanding stock options and restricted stock described below. The Company has historically issued new shares to satisfy stock option exercises or other awards issued under the 2018 Omnibus Plan and 2011 Omnibus Plan. Stock option awards have been granted with an exercise price equal to the market price of the Company’s stock at the date of grant. Stock option awards granted to employees under the plans to date are non-qualified stock options, have vesting over three years , subject to earlier vesting upon a change of control and certain other events, and have a seven-year contractual term. The Company grants shares of restricted stock as part of its long-term incentive plan. These shares of restricted stock generally vest over three years , subject to earlier vesting upon a change of control and certain other events. The value of restricted stock is based on the fair market value of the Company’s common stock at the date of grant. In addition, the Company has periodically granted shares of restricted stock to certain key executives that vests 25 % after three years , 25 % after four years and the remaining 50 % after five years , assuming the executive has been in continuous service to the Company since the award date, subject to earlier vesting upon a change of control and certain other events. Stock option and restricted stock compensation expense of $ 7.5 million, $ 5.7 million and $ 3.9 million, was recorded for the years ended December 31, 2024, 2023 and 2022, respectively, and is included in salaries, wages and employees’ benefits. As of December 31, 2024, there is unrecognized compensation expense of $ 7.2 million related to unvested stock options and restricted stock, which is expected to be recognized over a weighted average period of 1.7 years. The following table summarizes stock option activity for the year ended December 31, 2024 for employees: Options Weighted Average Exercise price Weighted Average Remaining Contractual Life Aggregate Intrinsic Value Outstanding at December 31, 2023 37,442 $ 170.79 3.8 $ 10,013 Exercised ( 20,086 ) 128.15 Forfeited ( 814 ) 240.57 Outstanding at December 31, 2024 16,542 $ 219.14 3.4 $ 3,914 Exercisable at December 31, 2024 11,686 $ 194.59 3.1 $ 3,052 The total intrinsic value of options exercised during the years ended December 31, 2024, 2023 and 2022 was $ 8.3 million, $ 7.0 million, and $ 10.8 million, respectively. The weighted-average grant-date fair value per share of options granted during the year ended December 31, 2022 was $ 94.36 . There were no options granted during the years ended December 31, 2024 and 2023. The following table summarizes the weighted average assumptions used in valuing options for the year ended December 31, 2022: 2022 Risk-free interest rate 1.92 % Expected life in years 3.5 Expected volatility 43.32 % Dividend rate — The risk-free interest rate for periods within the contractual life of the option is based on a three-month average U.S. Treasury yield at the time of grant. The expected life of the options represents the period of time that options granted are expected to be outstanding. Expected volatilities are based on historical volatility of the Company’s stock. The following table summarizes restricted stock activity during the year ended December 31, 2024: Shares Weighted Average Grant-date Fair Value Restricted Stock at December 31, 2023 51,956 $ 260.43 Granted 19,118 458.35 Vested ( 19,752 ) 239.80 Forfeited ( 1,148 ) 287.05 Restricted Stock at December 31, 2024 50,174 $ 343.36 The total fair value of restricted stock that vested during the years ended December 31, 2024, 2023, and 2022 were $ 9.7 million, $ 1.7 million and $ 2.1 million , respectively. Performance Unit Awards The Company grants performance unit awards to executives as part of the Company’s long term incentive plan. The criteria for payout of the awards is based on a comparison over the three-year performance period of these awards of the total stockholder return (TSR) of the Company’s common stock compared to the TSR of the companies in a peer group established by the Compensation Committee. These stock-based awards are accounted for in accordance with ASC Topic 718 with the expense amortized over the three-year vesting period based on the fair value of the awards at the grant date measured using the Monte Carlo method. Operating results include expense for the performance unit awards of $ 5.3 million in 2024, $ 4.5 million in 2023 and $ 3.8 million in 2022. Shares earned under the performance unit awards are issued in the first quarter of the year following the end of the performance period. There was an issuance of 23,434 shares for the January 2022 - December 2024 performance period in February 2025, 25,716 shares for the January 2021 - December 2023 performance period in February 2024, and 63,188 shares for the January 2020 - December 2022 performance period in February 2023. At December 31, 2024, performance unit awards are outstanding for a maximum of 27,838 shares for the January 2022 – December 2024 performance period and for a maximum of 15,914 shares for the January 2023 – December 2025 performance period. As of December 31, 2024, there is unrecognized compensation expense of $ 7.2 million related to unvested performance unit awards, which is expected to be recognized over a weighted average period of 1.8 years. The following table summarizes performance unit awards during the year ended December 31, 2024: Shares Weighted Average Grant-date Fair Value Performance Unit Awards at December 31, 2023 40,103 $ 345.08 Granted 8,682 808.34 Added by performance factor 13,327 285.44 Vested ( 25,716 ) 285.44 Forfeited ( 1,634 ) 321.70 Performance Unit Awards at December 31, 2024 34,762 $ 483.14 The total fair value of performance unit awards shares that vested during the years ended December 31, 2024, 2023, and 2022 were $ 13.7 million, $ 4.2 million and $ 3.6 million, respectively. Director Awards The 2018 Omnibus Plan provides for an annual grant to each non-employee director of shares of Saia stock with a value not to exceed $ 500,000 with the number of shares to be determined each year by the Compensation Committee. For 2024, 2023 and 2022 each non-employee director was granted 301 , 379 and 396 shares, respectively, of Saia stock under the 2018 Omnibus Plan. These shares vest in one year from grant, subject to accelerated vesting upon leaving the Board (other than for cause) or a change in control. Under the Director’s Deferred Fee Plan, non-employee directors may defer all or a portion of annual fees and awards earned. The deferrals are converted into units equivalent to the value of Company common stock. Upon the director’s termination, death or disability, accumulated deferrals are distributed in the form of Company common stock in accordance with elections made by the directors. Non-employee directors were issued 1,841 ; 2,729 ; and 3,272 units equivalent to shares in the Company's common stock under the Directors' Deferred Fee Plan during the years ended December 31, 2024, 2023 and 2022 , respectively.

Employee Benefits

Employee Benefits	12 Months Ended
	Dec. 31, 2024
Retirement Benefits [Abstract]
Employee Benefits	9. Employee Benefits Defined Contribution Plans The Company sponsors defined contribution plans, principally consisting of contributory 401(k) savings plans and noncontributory profit sharing plans. The Company’s contributions to the 401(k) savings plans consist of a matching percentage of employee contributions up to certain maximum limits. The Company match has historically been 50 percent of the first six percent of an eligible employee’s contributions. The Company’s total contributions to the 401(k) savings plans included in salaries, wages and employees' benefits for the years ended December 31, 2024, 2023 and 2022, were $ 19.0 million, $ 15.2 million, and $ 14.0 million, respectively. Cash Incentive Awards The Company provides cash incentive awards to certain salaried employees which are based primarily on actual operating results achieved for the year, compared to targeted operating results. Operating results include cash incentive awards of $ 12.4 million, $ 38.8 million, and $ 32.6 million in 2024, 2023 and 2022, respectively. Included in these amounts are also incentives that are based on other targets specifically associated with the respective employees' positions. Employee Stock Purchase Plan In January 2003, the Company adopted the Employee Stock Purchase Plan of Saia, Inc. (the ESPP) allowing eligible employees to purchase common stock of the Company at current market prices through payroll deductions of up to 10 percent of annual wages. In 2015, the Company amended the ESPP to allow highly compensated employees as defined by Section 401(a)(17) of the Internal Revenue Code to make payroll deductions of up to 20 percent of annual wages. The custodian uses the funds to purchase the Company’s common stock at current market prices. The custodian purchased 1,066 , 1,420 and 2,158 shares in the open market during 2024, 2023 and 2022 , respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes The income tax provision consists of the following (in thousands): 2024 2023 2022 Current: U.S. federal $ 37,563 $ 82,802 $ 68,934 State 13,159 18,498 20,058 Total current income tax provision 50,722 101,300 88,992 Deferred: U.S. federal 61,583 10,345 21,440 State 1,638 ( 275 ) 194 Total deferred income tax provision 63,221 10,070 21,634 Total income tax provision $ 113,943 $ 111,370 $ 110,626 A reconciliation between income taxes at the federal statutory rate (21 percent) and the actual income tax provision is as follows (in thousands): 2024 2023 2022 Provision at federal statutory rate $ 99,962 $ 97,908 $ 98,290 State income taxes, net of federal benefit 16,606 15,580 16,274 Tax credits ( 1,095 ) ( 1,181 ) ( 1,355 ) Excess tax benefit on stock compensation ( 923 ) ( 1,004 ) ( 1,578 ) Other, net ( 606 ) 67 ( 1,005 ) Total provision $ 113,943 $ 111,370 $ 110,626 Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Deferred tax (liabilities) assets are comprised of the following at December 31 (in thousands): 2024 2023 Depreciation $ ( 258,528 ) $ ( 196,494 ) Leases ( 31,473 ) ( 29,361 ) Other ( 6,855 ) ( 6,022 ) Gross deferred tax liabilities ( 296,856 ) ( 231,877 ) Allowance for credit losses 1,047 1,097 Equity-based compensation 5,531 4,834 Employee benefits 7,958 12,014 Leases 30,815 30,227 Claims and insurance 22,564 21,597 Other 10,032 6,982 Gross deferred tax assets 77,947 76,751 Valuation Allowance ( 153 ) ( 715 ) Net deferred tax assets 77,794 76,036 Net deferred tax liability $ ( 219,062 ) $ ( 155,841 ) The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction and various state jurisdictions. For the U.S. federal jurisdiction, tax years 2021 - 2024 remain open to examination. The expiration of the statute of limitations related to the various state income tax returns that the Company files varies by state. In general, tax years 2015 - 2024 remain open to examination by the various state and local jurisdictions. A reconciliation of the beginning and ending total amounts of gross unrecognized tax benefits is as follows (in thousands): 2024 2023 Gross unrecognized tax benefits at beginning of year $ 4,692 $ 3,867 Gross (decreases) increases in tax positions for prior years ( 1 ) 2 Gross increases in tax positions for current year 764 1,077 Settlements ( 731 ) — Lapse of statute of limitations ( 1,518 ) ( 254 ) Gross unrecognized tax benefits at end of year $ 3,206 $ 4,692 The Company recognizes interest and penalties related to uncertain tax positions as a component of income tax expense. The total amount of unrecognized tax benefits, which is recorded within claims, insurance and other liabilities on the consolidated balance sheets, that would affect the Company’s effective tax rate if recognized is $ 3.2 million and $ 4.7 million as of December 31, 2024 and 2023, respectively. The Company paid cash for income taxes of $ 101.2 million, $ 72.8 million, and $ 115.3 million in 2024, 2023 and 2022, respectively. The Company does not anticipate total unrecognized tax benefits will significantly change during the next twelve months due to the settlements of audits and the expiration of statutes of limitations.

Valuation and Qualifying Accoun

Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2024
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Valuation and Qualifying Accounts	11. Valuation and Qualifying Accounts The following is a rollforward of the allowance for credit losses for receivables (in thousands): Additions Balance, beginning of period Charged to costs and expenses Charged to other accounts Deductions(1) Balance, end of period For the period ended December 31, 2024 4,427 3,412 $ — $ ( 3,615 ) $ 4,224 For the period ended December 31, 2023 5,804 1,955 — ( 3,332 ) 4,427 For the period ended December 31, 2022 5,530 3,074 — ( 2,800 ) 5,804 (1) Primarily uncollectible accounts written off — net of recoveries.

Description of Business and S_2

Description of Business and Summary of Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Description of Business	Description of Business Saia, Inc., and its subsidiaries (Saia or the Company), is headquartered in Johns Creek, Georgia. Saia is a leading, less-than-truckload (LTL) motor carrier with more than 97 % of its revenue derived from transporting LTL shipments for customers. In addition to the core LTL services provided in the United States, the Company also offers customers a wide range of other value-added services, including non-asset truckload, expedited transportation and logistics services across North America.
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements include the accounts of Saia, Inc. and its wholly-owned subsidiaries. All significant intercompany accounts and transactions have been eliminated in the consolidated financial statements.
Use of Estimates	Use of Estimates The preparation of our consolidated financial statements in conformity with U.S. generally accepted accounting principles requires the use of estimates and assumptions that affect the reported amounts of assets and liabilities and the reported amounts of revenues and expenses. Management makes its best estimate of the ultimate outcome for these items based on historical trends and other information available when the financial statements are prepared. Changes in estimates are recognized in accordance with the accounting rules for the estimate, which is typically in the period when new information becomes available to management. Areas where the nature of the estimate makes it reasonably possible that actual results could materially differ from amounts estimated include: revenue reserves; self-insurance accruals; long-term incentive compensation; tax liabilities; loss contingencies; litigation claims; and impairment assessments on long-lived assets and goodwill. Recent Accounting Pronouncements Adopted in 2024 In November 2023, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2023-07, “ Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. ” The standard requires all entities with a single reportable segment to apply all segment disclosure requirements. This standard became effective for annual reporting periods beginning after December 15, 2023 and interim reporting periods beginning after December 15, 2024. The Company adopted the standard on a retrospective basis for the 2024 annual reporting period with the impact limited to incremental disclosures in our consolidated financial statements.
Recently Issued Accounting Pronouncements	Recent Accounting Pronouncements Adopted in 2024 In November 2023, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2023-07, “ Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. ” The standard requires all entities with a single reportable segment to apply all segment disclosure requirements. This standard became effective for annual reporting periods beginning after December 15, 2023 and interim reporting periods beginning after December 15, 2024. The Company adopted the standard on a retrospective basis for the 2024 annual reporting period with the impact limited to incremental disclosures in our consolidated financial statements. Recently Issued Accounting Pronouncements In December 2023, the FASB issued ASU No. 2023-09, “Income Taxes (Topic 740): Improvements to Income Tax Disclosures.” Under this ASU, income tax disclosures are expanded primarily by requiring the disaggregation of the rate reconciliation and income taxes paid disclosures. This standard is effective for annual reporting periods beginning after December 15, 2024. The Company is currently evaluating the impact of this standard on its consolidated financial statements and related disclosures. In November 2024, the FASB issued ASU No. 2024-03, "Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses." Under this ASU, entities are required to disclose additional disaggregated information related to certain expense captions included in the Consolidated Statements of Operations. This standard is effective for annual reporting periods beginning after December 15, 2026 and interim reporting periods beginning after December 15, 2027. The Company is currently evaluating the impact of this standard on its consolidated financial statements and related disclosures.
Cash and Cash Equivalents and Checks Outstanding	Cash and Cash Equivalents: Cash and cash equivalents includes cash on hand and short term marketable securities with original maturities of three months or less.
Parts, fuel and operating supplies	Spare Parts, Fuel and Operating Supplies: Spare parts, fuel and operating supplies on hand are carried at average cost and are included in other current assets on the accompanying consolidated balance sheets.
Property and Equipment Including Repairs and Maintenance	Property and Equipment: Property and equipment are carried at cost less accumulated depreciation. Replacements and improvements that extend the useful life of an asset are capitalized, while repairs and maintenance that do not improve or extend the lives of the respective assets are charged to expense as incurred. The Company evaluates long-lived assets for impairment whenever events or changes in circumstances indicate the carrying value of assets may not be recoverable. Depreciation is computed using the straight-line method, except for tractors (included in revenue equipment) for which the declining-balance method is used. The following service lives are used to compute depreciation: Years Structures 15 to 25 Revenue equipment 6 to 20 Technology equipment and software 3 to 5 Other 3 to 10 At December 31, property and equipment consisted of the following (in thousands): 2024 2023 Land $ 350,593 $ 272,633 Structures 1,238,969 813,146 Revenue equipment 1,810,389 1,470,913 Technology equipment and software 225,504 176,854 Other 164,614 148,254 Total property and equipment, at cost $ 3,790,069 $ 2,881,800 The Company’s investment in technology equipment and software consists primarily of systems to support customer service, maintenance and freight management. Depreciation and amortization expense (including amortization of assets under finance leases) was $ 209.2 million, $ 177.9 million and $ 156.2 million for the years ended December 31, 2024, 2023 and 2022, respectively. The Company periodically evaluates estimated useful lives of property and equipment considering its planned and actual usage, planned and actual maintenance and replacement, and other relevant physical and economic factors that may affect our use of the assets. During the second quarter of 2024, the Company determined that the estimated useful lives of certain of its trailers and dollies should be extended from 14 years to 20 years. This change was recognized prospectively. The changes in estimates resulted in an increase in income from continuing operations of approximately $ 7.7 million (a $ 5.8 mil lion increase in net income) for the year ended December 31, 2024.
Claims and Insurance Accruals	Claims and Insurance Accruals: The Company maintains a significant amount of insurance coverage with third-party insurance carriers that provides various levels of protection for covered risk exposure, including in the areas of workers’ compensation, bodily injury and property damage, casualty, cargo loss and damage and group health, with coverage limits and retention and deductible amounts that vary based on policy periods and claim type. Claims and insurance accruals related to workers’ compensation, bodily injury and property damage, casualty, cargo loss and damage and group health are established by management based on estimates of losses that the Company will ultimately incur on reported claims and on claims that have been incurred but not yet reported. Accruals are calculated on reported claims based on an evaluation of the nature and severity of the claim, historical loss experience and on legal, economic and other factors. Actuarial analysis is also used in calculating the accruals for workers’ compensation and bodily injury and property damage claims.
Income Taxes	Income Taxes: Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period enacted. As required by FASB Accounting Standards Codification (ASC) Topic 740, Income Taxes , the Company defines the threshold for recognizing the benefits of tax-filing positions in the financial statements as “more-likely-than-not” to be sustained by the tax authority.
Revenue Recognition	Revenue Recognition: The Company’s revenues are derived primarily from the transportation of freight as it satisfies performance obligations that arise from contracts with its customers. The Company’s performance obligations arise when it receives a bill of lading (BOL) to transport a customer's commodities at negotiated prices contained in either a transportation services agreement or a publicly disclosed tariff rate. Once a BOL is received and accepted, a legally-enforceable contract is formed whereby the parties are committed to perform and the rights of the parties, shipping terms and conditions, and payment terms have been identified. Each shipment represents a distinct service that is a separately identified performance obligation. The typical transit time to complete a shipment is from one to five days . Billing for transportation services normally occurs after completion of the service and payment is generally due within 30 days after the invoice date. The Company recognizes revenue related to the Company’s LTL, non-asset truckload and expedited transportation services over the transit time of the shipment as it moves from origin to destination based on the transit status at the end of each reporting period. Key estimates included in the recognition and measurement of revenue and related accounts receivable are as follows: • Revenue associated with shipments in transit is recognized ratably over transit time; and • Adjustments to revenue for billing adjustments and collectability. The portion of the gross invoice related to interline transportation services that involve the services of another party, such as another LTL service provider, is not recorded in the Company’s revenues. Revenue from logistics services is recognized as the services are provided.
Credit Risk	Credit Risk: The Company routinely grants credit to its customers. The risk of significant loss in trade receivables is substantially mitigated by the Company’s credit evaluation process, short collection terms, low revenue per transaction and services performed for a large number of customers, with no single customer representing more than 5 percent of accounts receivable at year-end. Allowances for potential credit losses are based on historical loss experience, current economic environment, expected trends and customer specific factors.
Stock-Based Compensation	Stock-Based Compensation: The Company has various stock-based compensation plans for its employees and non-employee directors. The Company stock-based compensation includes awards of stock options, restricted stock awards, and stock-based performance unit awards, all of which are accounted for under FASB ASC Topic 718, Compensation-Stock Compensation . Stock options granted to employees are valued using a Black-Scholes-Merton model with the expense amortized over the three-year vesting period. Restricted stock is valued based on the fair market value of the Company's common stock at the date of grant and the expense is amortized over the three to five year vesting period. Stock-based performance unit awards are valued using a Monte Carlo model and the expense is amortized over the three-year vesting period.
Intangible Assets	Intangible Assets: The Company tests goodwill for impairment annually and whenever events or changes in circumstance indicate that impairment may have occurred. The Company first performs a qualitative assessment to determine whether it is necessary to perform a quantitative assessment. The Company is not required to estimate the fair value of a reporting unit unless the Company determines, based on qualitative assessment, that it is more likely than not that its fair value is less than its carrying amount. Purchased intangible assets subject to amortization are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable.
Advertising	Advertising: The costs of advertising are expensed as incurred. Advertising costs charged to expense were $ 5.0 million, $ 2.9 million, and $ 7.2 million in 2024, 2023 and 2022 , respectively.
Financial Instruments	Financial Instruments: The carrying amounts of financial instruments including cash and cash equivalents, accounts receivable and accounts payable approximated fair value as of December 31, 2024 and 2023, because of the relatively short maturity of these instruments. See Note 2 for fair value disclosures related to debt. Segment Reporting: Saia is comprised of a single reportable segment organized around its transportation services. The segment provides core LTL and a wide range of other value-add transportation services to its customers based on negotiated prices contained in either a transportation services agreement or a publicly disclosed tariff rate. Saia derives revenue primarily in the United States and manages its business activities on a consolidated basis using an integrated transportation network. The chief operating decision maker (CODM) is the Chief Executive Officer who regularly reviews the operating results of the Company's single operating segment at the consolidated company level. The accounting policies of the segment are the same as those described in the summary of significant accounting policies. The CODM assesses performance for the segment and determines how to allocate resources based on Saia's consolidated net income. The CODM uses net income to evaluate income generated from segment assets (return on assets) in deciding whether to reinvest profits into the Company or for other purposes, such as for acquisitions, to repay borrowings or to pay dividends. The CODM also uses net income to monitor budget versus actual results, and in competitive analysis by benchmarking to the Company’s competitors. The competitive analysis along with the monitoring of budgeted versus actual results are used in assessing performance of the Company and in establishing management’s compensation. The measure of segment assets is reported on the balance sheet as total consolidated assets. The following table presents selected financial information with respect to the Company’s single reportable segment (in thousands): For The Years Ended December 31, 2024 2023 2022 Revenue $ 3,209,074 $ 2,881,433 $ 2,792,057 Less: Wages (a) 907,750 767,282 689,342 Salaries (a) 190,393 168,794 149,837 Purchased Transportation 237,306 238,688 315,896 Other Segment items (b) 1,179,631 1,065,270 1,009,337 Depreciation and Amortization 210,105 178,845 157,203 Interest Expense 8,930 2,535 2,611 Interest Income ( 1,049 ) ( 6,208 ) ( 217 ) Income Tax Expense 113,943 111,370 110,626 Segment and Consolidated Net Income $ 362,065 $ 354,857 $ 357,422 (a) Wages includes payroll costs for non-management employees generally paid on an hourly or per-mile basis. Salaries includes payroll costs for exempt employees. (b) Other segment items include employees' benefits, fuel, operating expenses and supplies, operating taxes and licenses and claims and insurance.

Description of Business and S_3

Description of Business and Summary of Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Summary of Property and Equipment, Estimated Useful Lives	Depreciation is computed using the straight-line method, except for tractors (included in revenue equipment) for which the declining-balance method is used. The following service lives are used to compute depreciation: Years Structures 15 to 25 Revenue equipment 6 to 20 Technology equipment and software 3 to 5 Other 3 to 10
Schedule of Property and Equipment	At December 31, property and equipment consisted of the following (in thousands): 2024 2023 Land $ 350,593 $ 272,633 Structures 1,238,969 813,146 Revenue equipment 1,810,389 1,470,913 Technology equipment and software 225,504 176,854 Other 164,614 148,254 Total property and equipment, at cost $ 3,790,069 $ 2,881,800
Schedule of Measure of Segment Assets	The following table presents selected financial information with respect to the Company’s single reportable segment (in thousands): For The Years Ended December 31, 2024 2023 2022 Revenue $ 3,209,074 $ 2,881,433 $ 2,792,057 Less: Wages (a) 907,750 767,282 689,342 Salaries (a) 190,393 168,794 149,837 Purchased Transportation 237,306 238,688 315,896 Other Segment items (b) 1,179,631 1,065,270 1,009,337 Depreciation and Amortization 210,105 178,845 157,203 Interest Expense 8,930 2,535 2,611 Interest Income ( 1,049 ) ( 6,208 ) ( 217 ) Income Tax Expense 113,943 111,370 110,626 Segment and Consolidated Net Income $ 362,065 $ 354,857 $ 357,422 (a) Wages includes payroll costs for non-management employees generally paid on an hourly or per-mile basis. Salaries includes payroll costs for exempt employees. (b) Other segment items include employees' benefits, fuel, operating expenses and supplies, operating taxes and licenses and claims and insurance.

Debt and Financing Arrangemen_2

Debt and Financing Arrangements (Tables)	12 Months Ended
	Dec. 31, 2024
Debt Disclosure [Abstract]
Summary of Reconciliation of Debt	At December 31, debt consisted of the following (in thousands): December 31, 2024 December 31, 2023 Credit Arrangements, described below $ 194,000 $ — Finance Leases, described below 6,294 16,488 Total debt 200,294 16,488 Less: current portion of long-term debt 5,313 10,173 Long-term debt, less current portion $ 194,981 $ 6,315

Commitments, Contingencies an_2

Commitments, Contingencies and Uncertainties (Tables)	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Schedule of Non-Cancellable Capital And Operating Lease Agreements Requiring Minimum Annual Rentals Payable	At December 31, 2024, the Company was committed under non-cancellable operating lease agreements requiring minimum annual rentals payable as follows (in thousands): Amount 2025 $ 36,094 2026 28,798 2027 25,324 2028 20,381 2029 14,988 Thereafter 21,763 Total $ 147,348

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2024
Leases [Abstract]
Summary of Lease Cost and Other Information	2024 2023 Finance lease cost: Amortization of right-of-use assets $ 3,770 $ 5,693 Interest on lease liabilities 426 883 Operating lease cost (includes variable and sublease costs as they are immaterial) 38,755 34,522 Short-term lease cost 15,336 16,303 Total lease cost $ 58,287 $ 57,401 Other Information Right-of-use assets obtained in exchange for new finance lease liabilities — — Right-of-use assets obtained in exchange for new operating lease liabilities 40,540 27,026
Summary of Supplemental Cash Flow and Balance Sheet Information Related to Leases	The discount rate used in the Company's calculation of its right-of-use assets and corresponding lease liabilities was determined based on the rate implicit in the lease if readily determinable, or its incremental borrowing rate, which approximates the rate at which the Company could borrow, on a collateralized basis, over the term of a lease. Supplemental cash flow and balance sheet information related to leases was as follows (in thousands, except where noted): 2024 2023 Cash paid for amounts included in the measurement of lease liabilities Operating cash outflows from finance leases $ 444 $ 890 Operating cash outflows from operating leases 37,844 35,339 Financing cash outflows from finance leases 10,193 14,520 Weighted-average remaining lease term - finance leases (years) 0.7 1.2 Weighted-average remaining lease term - operating leases (years) 5.2 5.4 Weighted-average discount rate - finance leases 4.1 % 4.0 % Weighted-average discount rate - operating leases 5.5 % 5.4 %
Summary of Maturity of Lease Liabilities	As of December 31, 2024, maturities of lease liabilities were as follows (in thousands): Operating Leases Finance Leases Maturity of Lease Liabilities 2025 $ 36,094 $ 5,434 2026 28,798 993 2027 25,324 - 2028 20,381 - 2029 14,988 - Thereafter 21,763 - Total lease payments 147,348 6,427 Less: Interest 23,178 133 Present value of lease liabilities $ 124,170 $ 6,294

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Gross Amounts and Accumulated Amortization of Identifiable Intangible Assets	The gross amounts and accumulated amortization of identifiable intangible assets are as follows (in thousands): December 31, 2024 December 31, 2023 Gross Amount Accumulated Amortization Gross Amount Accumulated Amortization Amortizable intangible assets: Customer relationships (useful life of 6 - 15 years) $ 19,000 $ 15,171 $ 19,000 $ 14,417 Trademarks (useful life of 15 years) 1,500 992 1,500 892 Total $ 20,500 $ 16,163 $ 20,500 $ 15,309
Summary of Estimated Amortization Expense for Next Five Years	Estimated amortization expense for the next five years is as follows (in thousands): Amount 2025 $ 853 2026 853 2027 853 2028 853 2029 853

Computation of Earnings Per S_2

Computation of Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Summary of Calculation of Basic Earnings Per Common Share and Diluted Earnings Per Common Share	The calculation of basic earnings per common share and diluted earnings per common share is as follows (in thousands except per share amounts): For The Years Ended December 31, 2024 2023 2022 Numerator: Net income $ 362,065 $ 354,857 $ 357,422 Denominator: Denominator for basic earnings per share–weighted 26,689 26,632 26,520 Dilutive effect of share-based awards 113 131 154 Denominator for diluted earnings per share–adjusted 26,802 26,763 26,674 Basic Earnings Per Share $ 13.57 $ 13.32 $ 13.48 Diluted Earnings Per Share $ 13.51 $ 13.26 $ 13.40

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Summary of Purchase and Sale of Common Stock	The following table summarizes the shares of the Company’s common stock that were purchased and sold by the Company’s rabbi trust (in thousands except share amounts): For The Years Ended December 31, 2024 2023 2022 Shares of common stock purchased 7,310 2,110 12,117 Aggregate purchase price of shares purchased $ 3,019 $ 620 $ 3,254 Shares of common stock sold 6,882 2,420 36,762 Aggregate sale price of shares sold $ 2,929 $ 835 $ 10,370

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]
Summary of Stock Option Activity	The following table summarizes stock option activity for the year ended December 31, 2024 for employees: Options Weighted Average Exercise price Weighted Average Remaining Contractual Life Aggregate Intrinsic Value Outstanding at December 31, 2023 37,442 $ 170.79 3.8 $ 10,013 Exercised ( 20,086 ) 128.15 Forfeited ( 814 ) 240.57 Outstanding at December 31, 2024 16,542 $ 219.14 3.4 $ 3,914 Exercisable at December 31, 2024 11,686 $ 194.59 3.1 $ 3,052
Summary of Weighted Average Assumptions Used In Valuing Options	The following table summarizes the weighted average assumptions used in valuing options for the year ended December 31, 2022: 2022 Risk-free interest rate 1.92 % Expected life in years 3.5 Expected volatility 43.32 % Dividend rate —
Summary of Restricted Stock Activity	The following table summarizes restricted stock activity during the year ended December 31, 2024: Shares Weighted Average Grant-date Fair Value Restricted Stock at December 31, 2023 51,956 $ 260.43 Granted 19,118 458.35 Vested ( 19,752 ) 239.80 Forfeited ( 1,148 ) 287.05 Restricted Stock at December 31, 2024 50,174 $ 343.36
Summary of Performance Unit Awards	The following table summarizes performance unit awards during the year ended December 31, 2024: Shares Weighted Average Grant-date Fair Value Performance Unit Awards at December 31, 2023 40,103 $ 345.08 Granted 8,682 808.34 Added by performance factor 13,327 285.44 Vested ( 25,716 ) 285.44 Forfeited ( 1,634 ) 321.70 Performance Unit Awards at December 31, 2024 34,762 $ 483.14

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Summary of Income Tax Provision	The income tax provision consists of the following (in thousands): 2024 2023 2022 Current: U.S. federal $ 37,563 $ 82,802 $ 68,934 State 13,159 18,498 20,058 Total current income tax provision 50,722 101,300 88,992 Deferred: U.S. federal 61,583 10,345 21,440 State 1,638 ( 275 ) 194 Total deferred income tax provision 63,221 10,070 21,634 Total income tax provision $ 113,943 $ 111,370 $ 110,626
Summary of Reconciliation Between Income Taxes and Effective Income Tax Provision	A reconciliation between income taxes at the federal statutory rate (21 percent) and the actual income tax provision is as follows (in thousands): 2024 2023 2022 Provision at federal statutory rate $ 99,962 $ 97,908 $ 98,290 State income taxes, net of federal benefit 16,606 15,580 16,274 Tax credits ( 1,095 ) ( 1,181 ) ( 1,355 ) Excess tax benefit on stock compensation ( 923 ) ( 1,004 ) ( 1,578 ) Other, net ( 606 ) 67 ( 1,005 ) Total provision $ 113,943 $ 111,370 $ 110,626
Summary of Deferred Tax Liabilities and Assets	Deferred tax (liabilities) assets are comprised of the following at December 31 (in thousands): 2024 2023 Depreciation $ ( 258,528 ) $ ( 196,494 ) Leases ( 31,473 ) ( 29,361 ) Other ( 6,855 ) ( 6,022 ) Gross deferred tax liabilities ( 296,856 ) ( 231,877 ) Allowance for credit losses 1,047 1,097 Equity-based compensation 5,531 4,834 Employee benefits 7,958 12,014 Leases 30,815 30,227 Claims and insurance 22,564 21,597 Other 10,032 6,982 Gross deferred tax assets 77,947 76,751 Valuation Allowance ( 153 ) ( 715 ) Net deferred tax assets 77,794 76,036 Net deferred tax liability $ ( 219,062 ) $ ( 155,841 )
Summary of Gross Unrecognized Tax Benefits	A reconciliation of the beginning and ending total amounts of gross unrecognized tax benefits is as follows (in thousands): 2024 2023 Gross unrecognized tax benefits at beginning of year $ 4,692 $ 3,867 Gross (decreases) increases in tax positions for prior years ( 1 ) 2 Gross increases in tax positions for current year 764 1,077 Settlements ( 731 ) — Lapse of statute of limitations ( 1,518 ) ( 254 ) Gross unrecognized tax benefits at end of year $ 3,206 $ 4,692

Valuation and Qualifying Acco_2

Valuation and Qualifying Accounts (Tables)	12 Months Ended
	Dec. 31, 2024
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Summary of Valuation and Qualifying Accounts	The following is a rollforward of the allowance for credit losses for receivables (in thousands): Additions Balance, beginning of period Charged to costs and expenses Charged to other accounts Deductions(1) Balance, end of period For the period ended December 31, 2024 4,427 3,412 $ — $ ( 3,615 ) $ 4,224 For the period ended December 31, 2023 5,804 1,955 — ( 3,332 ) 4,427 For the period ended December 31, 2022 5,530 3,074 — ( 2,800 ) 5,804 (1) Primarily uncollectible accounts written off — net of recoveries.

Description of Business and S_4

Description of Business and Summary of Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Description of Business and Summary of Significant Accounting Policies [Line Items]
Depreciation and amortization	$ 210,105	$ 178,845	$ 157,203
Net Income (Loss)	362,065	354,857	357,422
Advertising costs	$ 5,000	2,900	7,200
Credit Concentration Risk [Member] | Accounts Receivable [Member] | No Single Customer [Member]
Description of Business and Summary of Significant Accounting Policies [Line Items]
Percentage of accounts receivable	5%
Property and Equipment [Member]
Description of Business and Summary of Significant Accounting Policies [Line Items]
Depreciation and amortization	$ 209,200	$ 177,900	$ 156,200
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	7,700
Net Income (Loss)	$ 5,800
Minimum [Member]
Description of Business and Summary of Significant Accounting Policies [Line Items]
Percentage of revenue derived from transporting	97%
Average transit time	1 day
Minimum [Member] | Restricted Stock [Member]
Description of Business and Summary of Significant Accounting Policies [Line Items]
Stock-based awards compensation expense amortization period	3 years
Minimum [Member] | Property and Equipment [Member]
Description of Business and Summary of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	14 years
Maximum [Member]
Description of Business and Summary of Significant Accounting Policies [Line Items]
Average transit time	5 days
Maximum [Member] | Restricted Stock [Member]
Description of Business and Summary of Significant Accounting Policies [Line Items]
Stock-based awards compensation expense amortization period	5 years
Maximum [Member] | Property and Equipment [Member]
Description of Business and Summary of Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	20 years

Description of Business and S_5

Description of Business and Summary of Accounting Policies - Summary of Property and Equipment, Estimated Useful Lives (Detail)	Dec. 31, 2024
Structures [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, service lives	15 years
Structures [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, service lives	25 years
Revenue Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, service lives	6 years
Revenue Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, service lives	20 years
Technology Equipment and Software [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, service lives	3 years
Technology Equipment and Software [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, service lives	5 years
Other [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, service lives	3 years
Other [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, service lives	10 years

Description of Business and S_6

Description of Business and Summary of Accounting Policies - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	$ 3,790,069	$ 2,881,800
Land [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	350,593	272,633
Structures [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	1,238,969	813,146
Revenue Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	1,810,389	1,470,913
Technology Equipment and Software [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	225,504	176,854
Other [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment, at cost	$ 164,614	$ 148,254

Description of Business and S_7

Description of Business and Summary of Accounting Policies - Additional Information1 (Detail)	Dec. 31, 2024
Maximum [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2023-01-01
Description of Business and Summary of Significant Accounting Policies [Line Items]
Payment terms	30 days

Description of Business and S_8

Description of Business and Summary of Accounting Policies - Schedule of Measure of Segment Assets (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Revenue		$ 3,209,074	$ 2,881,433	$ 2,792,057
Wages	[1]	907,750	767,282	689,342
Salaries	[1]	190,393	168,794	149,837
Purchased Transportation		237,306	238,688	315,896
Other Segment items	[2]	1,179,631	1,065,270	1,009,337
Depreciation and amortization		210,105	178,845	157,203
Interest Expense		8,930	2,535	2,611
Interest Income		(1,049)	(6,208)	(217)
Income Tax Expense		113,943	111,370	110,626
Segment and Consolidated Net Income		$ 362,065	$ 354,857	$ 357,422
[1] Wages includes payroll costs for non-management employees generally paid on an hourly or per-mile basis. Salaries includes payroll costs for exempt employees. Other segment items include employees' benefits, fuel, operating expenses and supplies, operating taxes and licenses and claims and insurance.

Debt and Financing Arrangemen_3

Debt and Financing Arrangements - Summary of Reconciliation of Debt (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Debt Instruments [Abstract]
Credit Agreement with Banks, described below	$ 194,000	$ 0
Finance Leases, described below	6,294	16,488
Total debt	200,294	16,488
Less: current portion of long-term debt	5,313	10,173
Long-term debt, less current portion	$ 194,981	$ 6,315
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	us-gaap:FinanceLeaseLiabilityNoncurrent	us-gaap:FinanceLeaseLiabilityNoncurrent

Debt and Financing Arrangemen_4

Debt and Financing Arrangements - Additional Information (Detail) - USD ($) $ in Thousands			12 Months Ended
	May 01, 2024	Nov. 09, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Borrowing capacity under credit agreement			$ 194,000	$ 0
Initial Notes interest rate	6.09%
Maximum leverage ratio			3.50%
Finance lease liability			$ 6,294	16,488
Estimated fair value of the finance leases			6,300	16,100
Cash paid for interest			$ 7,700	1,600	$ 2,300
Maximum [Member]
Debt Instrument [Line Items]
Letter of credit unused portion fee			0.30%
Minimum [Member]
Debt Instrument [Line Items]
Letter of credit unused portion fee			0.175%
Base Rate Margin [Member] | Maximum [Member]
Debt Instrument [Line Items]
Rate margin			1%
Base Rate Margin [Member] | Minimum [Member]
Debt Instrument [Line Items]
Rate margin			0.25%
Secured Overnight Financing Rate [Member]
Debt Instrument [Line Items]
Rate margin			0.10%
Secured Overnight Financing Rate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Rate margin			2%
Secured Overnight Financing Rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Rate margin			1.25%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Borrowing capacity under credit agreement			$ 300,000
Borrowing capacity under credit agreement			$ 600,000
Adjusted Leverage Ratio			3.50%
Revolving Credit Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Borrowing capacity under credit agreement			$ 300,000
Revolving Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Borrowing capacity under credit agreement			150,000
Shelf Agreement [Member]
Debt Instrument [Line Items]
Borrowing capacity under credit agreement			100,000	0
Private Shelf Agreement [Member]
Debt Instrument [Line Items]
Uncommitted Private Shelf Agreement		$ 350,000
Private Shelf Agreement [Member] | Maximum [Member]
Debt Instrument [Line Items]
Selling of aggregate principal amount	$ 100,000
Existing Credit Agreement [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Borrowing capacity under credit agreement			94,000	0
Letter of credit facility outstanding amount			$ 32,200	$ 32,100

Commitments, Contingencies an_3

Commitments, Contingencies and Uncertainties - Schedule of Non-Cancellable Capital and Operating Lease Agreements Requiring Minimum Annual Rentals Payable (Detail) $ in Thousands	Dec. 31, 2024 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2025	$ 36,094
2026	28,798
2027	25,324
2028	20,381
2029	14,988
Thereafter	21,763
Total	$ 147,348

Commitments, Contingencies an_4

Commitments, Contingencies and Uncertainties - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Other Commitments [Line Items]
Rent expense	$ 42.5	$ 37.2	$ 33.4
Purchase commitments related to capital expenditures	27.6
Capital expenditures in accounts payable	$ 24.4	$ 50.9

Leases - Additional Information

Leases - Additional Information (Detail) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Leases [Abstract]
Finance leased assets, net	$ 18.2	$ 38.6
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Property and Equipment, at cost	Property and Equipment, at cost
Accumulated depreciation and amortization of finance leased assets	$ 16.2	$ 31.2

Leases - Summary of Lease Cost

Leases - Summary of Lease Cost and Other Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Finance lease cost:
Amortization of right-of-use assets	$ 3,770	$ 5,693
Interest on lease liabilities	426	883
Operating lease cost (includes variable and sublease costs as they are immaterial)	38,755	34,522
Short-term lease cost	15,336	16,303
Total lease cost	58,287	57,401
Other Information
Right-of-use assets obtained in exchange for new finance lease liabilities	0	0
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 40,540	$ 27,026

Leases - Summary of Supplementa

Leases - Summary of Supplemental Cash Flow and Balance Sheet Information Related to Leases (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash paid for amounts included in the measurement of lease liabilities
Operating cash outflows from finance leases	$ 444	$ 890
Operating cash outflows from operating leases	37,844	35,339
Financing cash outflows from finance leases	$ 10,193	$ 14,520	$ 19,471
Weighted-average remaining lease term - finance leases (years)	8 months 12 days	1 year 2 months 12 days
Weighted-average remaining lease term - operating leases (years)	5 years 2 months 12 days	5 years 4 months 24 days
Weighted-average discount rate - finance leases	4.10%	4%
Weighted-average discount rate - operating leases	5.50%	5.40%

Leases - Summary of Maturity of

Leases - Summary of Maturity of Lease Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Operating Leases
2025	$ 36,094
2026	28,798
2027	25,324
2028	20,381
2029	14,988
Thereafter	21,763
Total lease payments	147,348
Less: Interest	23,178
Present value of lease liabilities	124,170
Finance Leases
2025	5,434
2026	993
2027	0
2028	0
2029	0
Thereafter	0
Total lease payments	6,427
Less: Interest	133
Finance Leases, described below	$ 6,294	$ 16,488
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	us-gaap:FinanceLeaseLiabilityNoncurrent	us-gaap:FinanceLeaseLiabilityNoncurrent

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	$ 12.1	$ 12.1	$ 12.1
Amortization expense for intangible assets	$ 0.9	$ 0.9	$ 1

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Summary of Gross Amounts and Accumulated Amortization of Identifiable Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 20,500	$ 20,500
Accumulated Amortization	16,163	15,309
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	19,000	19,000
Accumulated Amortization	15,171	14,417
Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	1,500	1,500
Accumulated Amortization	$ 992	$ 892

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets - Summary of Gross Amounts and Accumulated Amortization of Identifiable Intangible Assets (Parenthetical) (Detail)	Dec. 31, 2024
Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, useful life	15 years
Minimum [Member] | Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, useful life	6 years
Maximum [Member] | Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, useful life	15 years

Goodwill and Other Intangible_6

Goodwill and Other Intangible Assets - Summary of Estimated Amortization Expense for Next Five Years (Detail) $ in Thousands	Dec. 31, 2024 USD ($)
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2025	$ 853
2026	853
2027	853
2028	853
2029	$ 853

Computation of Earnings Per S_3

Computation of Earnings Per Share - Summary of Calculation of Basic Earnings Per Common Share and Diluted Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Numerator:
Net income	$ 362,065	$ 354,857	$ 357,422
Denominator:
Denominator for basic earnings per share–weighted average common shares	26,689	26,632	26,520
Dilutive effect of share-based awards	113	131	154
Denominator for diluted earnings per share–adjusted weighted average common shares	26,802	26,763	26,674
Basic Earnings Per Share	$ 13.57	$ 13.32	$ 13.48
Diluted Earnings Per Share	$ 13.51	$ 13.26	$ 13.40

Computation of Earnings Per S_4

Computation of Earnings Per Share - Additional Information (Detail) - shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Earnings Per Share [Abstract]
Common stock excluded from the calculation of diluted earnings per share	50	5,790	22,237

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Purchase and Sale of Common Stock (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Equity [Abstract]
Shares of common stock purchased	7,310	12,117	2,110
Aggregate purchase price of shares purchased	$ 3,019	$ 3,254	$ 620
Shares of common stock sold	6,882	36,762	2,420
Aggregate sale price of shares sold	$ 2,929	$ 10,370	$ 835

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - shares	Dec. 31, 2024	Dec. 31, 2023
Equity [Abstract]
Common stock shares held by Rabbi Trust	70,100	69,672
Shares reserved for issuance under the Directors Deferred Fee Plan	101,951	100,110

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Feb. 28, 2025	Feb. 29, 2024	Feb. 28, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding stock options	16,542	37,442
Stock-based compensation	$ 14,243,000	$ 11,636,000	$ 8,827,000
Unrecognized compensation expense	$ 7,200,000
Weighted average recognition period of compensation expenses	1 year 8 months 12 days
Total intrinsic value of options exercised	$ 8,300,000	$ 7,000,000		$ 10,800,000
Weighted-average grant-date fair value per share of options granted	$ 0	$ 0	$ 94.36
Stock Option and Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 7,500,000	$ 5,700,000	$ 3,900,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of shares vested	$ 9,700,000	1,700,000	2,100,000
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting period	3 years
Unrecognized compensation expense	$ 7,200,000
Weighted average recognition period of compensation expenses	1 year 9 months 18 days
Operating expense	$ 5,300,000	4,500,000	3,800,000
Fair value of shares vested	$ 13,700,000	$ 4,200,000	$ 3,600,000
After three years [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting percentage	25%
After three years [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting period	3 years
After five years [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting period	50 years
After five years [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting period	5 years
After four years [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting percentage	25%
After four years [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting period	4 years
January 2020 - December 2022 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period share issuance range						25,716
January 2019 - December 2021 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period share issuance range							63,188
January 2020 – December 2022 [Member] | Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period share issuance range					23,434
Maximum [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting period	5 years
Maximum [Member] | January 2022 - December 2024 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance unit awards, outstanding	27,838
Maximum [Member] | January 2023 - December 2025 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance unit awards, outstanding	15,914
Minimum [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock vesting period	3 years
Non Employee Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual service	3 years
Contractual term	7 years
Restricted stock vesting period	3 years
2018 Omnibus Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved	1,100,000
Reserved and unissued shares	633,409	677,500
2018 Omnibus Incentive Plan [Member] | Non Employee Director [Member] | Director Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued to non employee director	301	379	396
2018 Omnibus Incentive Plan [Member] | Non Employee Director [Member] | Maximum [Member] | Director Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual grant amount	$ 500,000
2011 Omnibus Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved	2,350,000
Additional grant under Plan	0
Reserved and unissued shares	391,089	391,089
Directors' Deferred Fee Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued to non employee director	1,841	2,729	3,272

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Beginning balance, options	37,442
Exercised, options	(20,086)
Forfeited, options	(814)
Ending balance, options	16,542	37,442
Exercisable, options	11,686
Beginning balance, weighted average exercise price	$ 170.79
Exercised	128.15
Forfeited	240.57
Ending balance, weighted average exercise price	219.14	$ 170.79
Exercisable, weighted average exercisable price	$ 194.59
Outstanding, weighted average remaining contractual life (years)	3 years 4 months 24 days	3 years 9 months 18 days
Exercisable, weighted average remaining contractual life (years)	3 years 1 month 6 days
Outstanding, aggregate intrinsic value	$ 3,914	$ 10,013
Exercisable, aggregate intrinsic value	$ 3,052

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Weighted Average Assumptions Used In Valuing Options (Detail)	12 Months Ended
	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Risk-free interest rate	1.92%
Expected life in years	3 years 6 months
Expected volatility	43.32%
Dividend rate	0%

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Restricted Stock Activity (Detail) - Restricted Stock [Member]	12 Months Ended
	Dec. 31, 2024 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested, options beginning balance | shares	51,956
Granted, options | shares	19,118
Vested, options | shares	(19,752)
Forfeited, options | shares	(1,148)
Unvested, options ending balance | shares	50,174
Unvested, weighted average grant date fair value beginning balance | $ / shares	$ 260.43
Granted | $ / shares	458.35
Vested | $ / shares	239.8
Forfeited | $ / shares	287.05
Unvested, weighted average grant date fair value ending balance | $ / shares	$ 343.36

Stock-Based Compensation - Su_4

Stock-Based Compensation - Summary of Performance Unit Awards (Details) - Performance Shares [Member]	12 Months Ended
	Dec. 31, 2024 $ / shares shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unvested, options beginning balance | shares	40,103
Granted, options | shares	8,682
Added by performance factor, options | shares	13,327
Vested, options | shares	(25,716)
Forfeited, options | shares	(1,634)
Unvested, options ending balance | shares	34,762
Unvested, weighted average grant date fair value beginning balance | $ / shares	$ 345.08
Granted | $ / shares	808.34
Added by performance factor | $ / shares	285.44
Vested | $ / shares	285.44
Forfeited | $ / shares	321.7
Unvested, weighted average grant date fair value ending balance | $ / shares	$ 483.14

Employee Benefits - Additional

Employee Benefits - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Shares held by the rabbi trust	70,100	69,672
Cash incentive awards	$ 12.4	$ 38.8	$ 32.6
Shares purchased by custodians	1,066	1,420	2,158
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Payroll deduction for ESPP, percent of annual wages	10%
Highly Compensated Employees [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Payroll deduction for ESPP, percent of annual wages	20%
401(k)Saving Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Company match of contribution	50%
Employees contribution share	6%
Contribution in operation	$ 19	$ 15.2	$ 14

Income Taxes - Summary of Incom

Income Taxes - Summary of Income Tax Provision (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Current:
U.S. federal	$ 37,563	$ 82,802	$ 68,934
State	13,159	18,498	20,058
Total current income tax provision	50,722	101,300	88,992
Deferred:
U.S. federal	61,583	10,345	21,440
State	1,638	(275)	194
Total deferred income tax provision	63,221	10,070	21,634
Total provision	$ 113,943	$ 111,370	$ 110,626

Income Taxes - Summary of Recon

Income Taxes - Summary of Reconciliation Between Income Taxes and Effective Income Tax Provision (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Provision at federal statutory rate	$ 99,962	$ 97,908	$ 98,290
State income taxes, net of federal benefit	16,606	15,580	16,274
Tax credits	(1,095)	(1,181)	(1,355)
Excess tax benefit on stock compensation	(923)	(1,004)	(1,578)
Other, net	(606)	67	(1,005)
Total provision	$ 113,943	$ 111,370	$ 110,626

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax [Line Items]
Unrecognized tax benefits that would affect the Company's effective tax rate if recognized	$ 3.2	$ 4.7
Cash (received) paid for income taxes	$ 101.2	$ 72.8	$ 115.3
Maximum [Member]
Income Tax [Line Items]
Income tax year open for examination	2024
Maximum [Member] | State and Local Jurisdiction [Member]
Income Tax [Line Items]
Income tax year open for examination	2024
Minimum [Member]
Income Tax [Line Items]
Income tax year open for examination	2021
Minimum [Member] | State and Local Jurisdiction [Member]
Income Tax [Line Items]
Income tax year open for examination	2015

Income Taxes - Summary of Defer

Income Taxes - Summary of Deferred Tax Liabilities and Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Depreciation	$ (258,528)	$ (196,494)
Leases	(31,473)	(29,361)
Other	(6,855)	(6,022)
Gross deferred tax liabilities	(296,856)	(231,877)
Allowance for credit losses	1,047	1,097
Equity-based compensation	5,531	4,834
Employee benefits	7,958	12,014
Leases	30,815	30,227
Claims and insurance	22,564	21,597
Other	10,032	6,982
Gross deferred tax assets	77,947	76,751
Valuation Allowance	(153)	(715)
Net deferred tax assets	77,794	76,036
Net deferred tax liability	$ (219,062)	$ (155,841)

Income Taxes - Summary of Gross

Income Taxes - Summary of Gross Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Gross unrecognized tax benefits at beginning of year	$ 4,692	$ 3,867
Gross (decreases) increases in tax positions for prior years	(1)	2
Gross increases in tax positions for current year	764	1,077
Settlements	(731)	0
Lapse of statute of limitations	(1,518)	(254)
Gross unrecognized tax benefits at end of year	$ 3,206	$ 4,692

Valuation and Qualifying Acco_3

Valuation and Qualifying Accounts - Summary of Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance, beginning of period		$ 4,427	$ 5,804	$ 5,530
Additions - Charged to costs and expenses		3,412	1,955	3,074
Additions - Charged to other accounts		0	0	0
Deductions	[1]	(3,615)	(3,332)	(2,800)
Balance, end of period		$ 4,224	$ 4,427	$ 5,804
[1] Primarily uncollectible accounts written off — net of recoveries.