ArcBest (ARCB) 10-Q 3 May 24 2024 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2024	Apr. 30, 2024
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	000-19969
Entity Registrant Name	ARCBEST CORPORATION
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	71-0673405
Entity Address, Address Line One	8401 McClure Drive
Entity Address, City or Town	Fort Smith
Entity Address, State or Province	AR
Entity Address, Postal Zip Code	72916
City Area Code	479
Local Phone Number	785-6000
Title of 12(b) Security	Common Stock
Trading Symbol	ARCB
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		23,431,641
Entity Central Index Key	0000894405
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
CURRENT ASSETS
Cash and cash equivalents	$ 172,855	$ 262,226
Short-term investments	68,065	67,842
Accounts receivable, less allowances (2024 - $9,184; 2023 - $10,346)	433,717	430,122
Other accounts receivable, less allowances (2024 - $733; 2023 - $731)	11,389	52,124
Prepaid expenses	39,232	37,034
Prepaid and refundable income taxes	22,084	24,319
Other	11,136	11,116
TOTAL CURRENT ASSETS	758,478	884,783
PROPERTY, PLANT AND EQUIPMENT
Land and structures	491,555	460,068
Revenue equipment	1,119,446	1,126,055
Service, office, and other equipment	318,252	319,466
Software	176,988	173,354
Leasehold improvements	25,173	24,429
TOTAL PROPERTY, PLANT AND EQUIPMENT, Gross	2,131,414	2,103,372
Less allowances for depreciation and amortization	1,193,584	1,188,548
PROPERTY, PLANT AND EQUIPMENT, net	937,830	914,824
GOODWILL	304,753	304,753
INTANGIBLE ASSETS, net	97,940	101,150
OPERATING RIGHT-OF-USE ASSETS	174,987	169,999
DEFERRED INCOME TAXES	10,032	8,140
OTHER LONG-TERM ASSETS	73,123	101,445
TOTAL ASSETS	2,357,143	2,485,094
CURRENT LIABILITIES
Accounts payable	209,908	214,004
Income taxes payable	8	10,410
Accrued expenses	313,494	378,029
Current portion of long-term debt	63,179	66,948
Current portion of operating lease liabilities	31,986	32,172
TOTAL CURRENT LIABILITIES	618,575	701,563
LONG-TERM DEBT, less current portion	148,992	161,990
OPERATING LEASE LIABILITIES, less current portion	174,085	176,621
POSTRETIREMENT LIABILITIES, less current portion	13,318	13,319
CONTINGENT CONSIDERATION	100,220	92,900
OTHER LONG-TERM LIABILITIES	34,422	40,553
DEFERRED INCOME TAXES	44,798	55,785
STOCKHOLDERS' EQUITY
Common stock, $0.01 par value, authorized 70,000,000 shares; issued 2024: 30,038,556 shares; 2023: 30,024,125 shares	300	300
Additional paid-in capital	343,102	340,961
Retained earnings	1,267,444	1,272,584
Treasury stock, at cost, 2024: 6,580,818 shares; 2023: 6,460,137 shares	(391,458)	(375,806)
Accumulated other comprehensive income	3,345	4,324
TOTAL STOCKHOLDERS' EQUITY	1,222,733	1,242,363
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 2,357,143	$ 2,485,094

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
CONSOLIDATED BALANCE SHEETS
Accounts receivable, allowances (in dollars)	$ 9,184	$ 10,346
Other accounts receivable, allowances (in dollars)	$ 733	$ 731
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized shares	70,000,000	70,000,000
Common stock, issued shares	30,038,556	30,024,125
Treasury stock, at cost, shares	6,580,818	6,460,137

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
CONSOLIDATED STATEMENTS OF OPERATIONS
REVENUES	$ 1,036,419	$ 1,106,094
OPERATING EXPENSES	1,013,984	1,084,935
OPERATING INCOME	22,435	21,159
OTHER INCOME (COSTS)
Interest and dividend income	3,315	2,933
Interest and other related financing costs	(2,228)	(2,327)
Other, net	(28,199)	1,780
TOTAL OTHER INCOME (COSTS)	(27,112)	2,386
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(4,677)	23,545
INCOME TAX PROVISION (BENEFIT)	(1,765)	4,698
NET INCOME (LOSS) FROM CONTINUING OPERATIONS	(2,912)	18,847
INCOME FROM DISCONTINUED OPERATIONS, NET OF TAX	600	52,436
NET INCOME (LOSS)	$ (2,312)	$ 71,283
BASIC EARNINGS PER COMMON SHARE
Continuing operations (in dollars per share)	$ (0.12)	$ 0.78
Discontinued operations (in dollars per share)	0.03	2.16
BASIC EARNINGS PER COMMON SHARE (in dollars per share)	(0.10)	2.93
DILUTED EARNINGS PER COMMON SHARE
Continuing operations (in dollars per share)	(0.12)	0.75
Discontinued operations (in dollars per share)	0.03	2.09
DILUTED EARNINGS PER COMMON SHARE (in dollars per share)	$ (0.10)	$ 2.84
AVERAGE COMMON SHARES OUTSTANDING
Basic (in shares)	23,561,309	24,288,138
Diluted (in shares)	23,561,309	25,057,726

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net Income (Loss)	$ (2,312)	$ 71,283
Amortization of unrecognized net periodic benefit cost (credit), net of tax: (2024 - $65; 2023 - $86)
Net actuarial gain	(187)	(247)
Interest rate swap and foreign currency translation:
Change in unrealized loss on interest rate swap, net of tax: (2024 - $130; 2023 - $161)	(366)	(452)
Change in foreign currency translation, net of tax: (2024 - $150; 2023 - $6)	(426)	(18)
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(979)	(717)
TOTAL COMPREHENSIVE INCOME (LOSS)	$ (3,291)	$ 70,566

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Amortization of unrecognized net periodic benefit cost (credit), tax	$ (65)	$ (86)
Change in unrealized gain (loss) on interest rate swap, tax	(130)	(161)
Change in foreign currency translation, tax	$ (150)	$ (6)

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income	Total
Balances at Dec. 31, 2022	$ 298	$ 339,582	$ 1,088,693	$ (284,275)	$ 7,103	$ 1,151,401
Balances (in shares) at Dec. 31, 2022	29,759,000
Balances, Treasury stock (in shares) at Dec. 31, 2022				5,529,000
Increase (Decrease) in Stockholders' Equity
Net income (loss)			71,283			71,283
Other comprehensive income (loss), net of tax					(717)	(717)
Issuance of common stock under share-based compensation plans (in shares)	50,000
Shares withheld for employee tax remittance on share-based compensation		(1,590)				(1,590)
Share-based compensation expense		2,489				2,489
Purchase of treasury stock				$ (14,092)		(14,092)
Purchase of treasury stock (in shares)				154,000
Dividends declared on common stock			(2,915)			(2,915)
Balances at Mar. 31, 2023	$ 298	340,481	1,157,061	$ (298,367)	6,386	1,205,859
Balances (in shares) at Mar. 31, 2023	29,809,000
Balances, Treasury stock (in shares) at Mar. 31, 2023				5,683,000
Balances at Dec. 31, 2023	$ 300	340,961	1,272,584	$ (375,806)	4,324	$ 1,242,363
Balances (in shares) at Dec. 31, 2023	30,024,000
Balances, Treasury stock (in shares) at Dec. 31, 2023				6,460,000		6,460,137
Increase (Decrease) in Stockholders' Equity
Net income (loss)			(2,312)			$ (2,312)
Other comprehensive income (loss), net of tax					(979)	(979)
Issuance of common stock under share-based compensation plans (in shares)	15,000
Shares withheld for employee tax remittance on share-based compensation		(748)				(748)
Share-based compensation expense		2,889				2,889
Purchase of treasury stock				$ (15,652)		(15,652)
Purchase of treasury stock (in shares)				121,000
Dividends declared on common stock			(2,828)			(2,828)
Balances at Mar. 31, 2024	$ 300	$ 343,102	$ 1,267,444	$ (391,458)	$ 3,345	$ 1,222,733
Balances (in shares) at Mar. 31, 2024	30,039,000
Balances, Treasury stock (in shares) at Mar. 31, 2024				6,581,000		6,580,818

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
OPERATING ACTIVITIES
Net income (loss)	$ (2,312)	$ 71,283
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	33,616	32,187
Amortization of intangibles	3,217	3,203
Share-based compensation expense	2,889	2,235
Provision for losses on accounts receivable	1,055	1,427
Change in deferred income taxes	(12,548)	(9,814)
(Gain) loss on sale of property and equipment	217	(9)
Pre-tax gain on sale of discontinued operations	(806)	(69,083)
Change in fair value of contingent consideration	7,320	15,040
Change in fair value of equity investment	28,739
Changes in operating assets and liabilities:
Receivables	35,059	43,977
Prepaid expenses	(2,198)	(1,464)
Other assets	(1,218)	3,874
Income taxes	(8,305)	6,221
Operating right-of-use assets and lease liabilities, net	(7,710)	1,570
Accounts payable, accrued expenses, and other liabilities	(70,548)	(79,984)
NET CASH PROVIDED BY OPERATING ACTIVITIES	6,467	20,663
INVESTING ACTIVITIES
Purchases of property, plant and equipment, net of financings	(55,049)	(34,657)
Proceeds from sale of property and equipment	1,292	1,833
Proceeds from sale of discontinued operations		101,138
Purchases of short-term investments	(5,236)	(35,588)
Proceeds from sale of short-term investments	5,635	41,865
Capitalization of internally developed software	(3,635)	(3,631)
NET CASH PROVIDED BY (USED IN) INVESTING ACTIVITIES	(56,993)	70,960
FINANCING ACTIVITIES
Payments on long-term debt	(16,767)	(17,649)
Net change in book overdrafts	(2,850)	(10,493)
Deferred financing costs		63
Payment of common stock dividends	(2,828)	(2,915)
Purchases of treasury stock	(15,652)	(14,092)
Payments for tax withheld on share-based compensation	(748)	(1,590)
NET CASH USED IN FINANCING ACTIVITIES	(38,845)	(46,676)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(89,371)	44,947
CASH AND CASH EQUIVALENTS AT END OF PERIOD	172,855	203,319
NONCASH INVESTING ACTIVITIES
Equipment financed		3,478
Accruals for equipment received	915	1,453
Lease liabilities arising from obtaining right-of-use assets	$ 5,694	$ 30,581

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
CONSOLIDATED STATEMENTS OF CASH FLOWS
Cash and cash equivalents of continuing operations at beginning of period	$ 262,226	$ 158,264
Cash and cash equivalents of discontinued operations at beginning of period		$ 108

ORGANIZATION AND DESCRIPTION OF

ORGANIZATION AND DESCRIPTION OF THE BUSINESS AND FINANCIAL STATEMENT PRESENTATION	3 Months Ended
	Mar. 31, 2024
ORGANIZATION AND DESCRIPTION OF THE BUSINESS AND FINANCIAL STATEMENT PRESENTATION
ORGANIZATION AND DESCRIPTION OF THE BUSINESS AND FINANCIAL STATEMENT PRESENTATION	NOTE A – ORGANIZATIO N AND DESCRIPTION OF THE BUSINESS AND FINANCIAL STATEMENT PRESENTATION ​ Organization and Description of Business ​ ArcBest Corporation ™ ® ​ The Asset-Based segment represented approximately 63% of the Company’s total revenues before other revenues and intercompany eliminations for the three months ended March 31, 2024. As of March 2024, approximately 82% of the Asset-Based segment’s employees were covered under a collective bargaining agreement, the ABF National Master Freight Agreement (the “2023 ABF NMFA”), with the International Brotherhood of Teamsters (the “IBT”), which will remain in effect through June 30, 2028. ​ Financial Statement Presentation ​ On February 28, 2023, the Company sold FleetNet America, Inc. (“FleetNet”), a wholly owned subsidiary and reportable operating segment of the Company, for an aggregate adjusted cash purchase price of $100.9 million, including post-closing adjustments. The sale of FleetNet ® ​ For the three months ended March 31, 2023, certain reclassifications have been made between operating expenses lines of the Asset-Light segment to conform to the current-year presentation (see Note J). There was no impact on total Asset-Light operating expenses as a result of these reclassifications. ​ The accompanying unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States and applicable rules and regulations of the Securities and Exchange Commission (the “SEC”) pertaining to interim financial information. Accordingly, these interim financial statements do not include all information or footnote disclosures required by accounting principles generally accepted in the United States for complete financial statements and, therefore, should be read in conjunction with the audited financial statements and accompanying notes included in the Company’s 2023 Annual Report on Form 10-K and other current filings with the SEC. In the opinion of management, all adjustments (which are of a normal and recurring nature) considered necessary for a fair presentation have been included. ​ The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual amounts may differ from those estimates. ​ ​ Accounting Pronouncements Not Yet Adopted ​ Accounting Standards Codification (“ASC”) Topic 280, Segment Reporting Improvements to Reportable Segment Disclosures ​ ASC Topic 740, Income Taxes Improvements to Income Tax Disclosures ​ In March 2024, the SEC adopted final rules under SEC Release Nos. 33-11275 and 33-99678, The Enhancement and Standardization of Climate-Related Disclosures for Investors ​

FINANCIAL INSTRUMENTS AND FAIR

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2024
FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS
FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS	NOTE B – FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS ​ Financial Instruments ​ The following table presents the components of cash and cash equivalents and short-term investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31 December 31 ​ ​ 2024 ​ 2023 ​ ​ (in thousands) ​ Cash and cash equivalents ​ ​ ​ ​ ​ ​ ​ Cash deposits (1) ​ $ 140,655 ​ $ 168,472 ​ Money market funds (2) ​ 32,200 ​ 93,754 ​ Total cash and cash equivalents ​ $ 172,855 ​ $ 262,226 ​ ​ ​ ​ ​ ​ ​ ​ ​ Short-term investments ​ ​ ​ ​ ​ ​ ​ Certificates of deposit (1) ​ $ 68,065 ​ $ 67,842 ​ ​ (1) Recorded at cost plus accrued interest, which approximates fair value. (2) Recorded at fair value as determined by quoted market prices (see amounts presented in the table of financial assets and liabilities measured at fair value within this Note). ​ The Company’s long-term financial instruments are presented in the table of financial assets and liabilities measured at fair value within this Note. ​ Concentrations of Credit Risk of Financial Instruments The Company is potentially subject to concentrations of credit risk related to its cash, cash equivalents, and short-term investments. The Company reduces credit risk by maintaining its cash deposits and short-term investments in accounts and certificates of deposit which are primarily FDIC-insured or in direct obligations of the U.S. government. However, certain cash deposits and certificates of deposit may exceed federally insured limits. At March 31, 2024 and December 31, 2023, cash deposits and short-term investments totaling $60.0 million and $76.3 million, respectively, were not FDIC insured. The Company also holds money market funds, which are invested in U.S. government securities and repurchase agreements collateralized solely by U.S. government securities. ​ Fair Value Disclosure of Financial Instruments Fair value disclosures are made in accordance with the following hierarchy of valuation techniques based on whether the inputs of market data and market assumptions used to measure fair value are observable or unobservable: ​ ● Level 1 — Quoted prices for identical assets and liabilities in active markets. ● Level 2 — Quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets and liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data. ● Level 3 — Unobservable inputs (Company’s market assumptions) that are significant to the valuation model. ​ Fair value and carrying value disclosures of financial instruments are presented in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31 ​ December 31 ​ ​ 2024 2023 ​ ​ (in thousands) ​ ​ ​ ​ Carrying ​ Fair ​ Carrying ​ Fair ​ ​ ​ ​ Value ​ Value ​ Value ​ Value ​ Credit Facility (1) ​ $ 50,000 ​ $ 50,000 ​ $ 50,000 ​ $ 50,000 ​ Notes payable (2) ​ 162,171 ​ 159,385 ​ 178,938 ​ 177,149 ​ New England Pension Fund withdrawal liability (3) ​ ​ 19,222 ​ ​ 17,734 ​ ​ 19,402 ​ ​ 18,220 ​ ​ ​ $ 231,393 ​ $ 227,119 ​ $ 248,340 ​ $ 245,369 ​ ​ (1) The revolving credit facility (the “Credit Facility”) carries a variable interest rate based on Secured Overnight Financing Rate (“SOFR”), plus a margin, priced at market for debt instruments having similar terms and collateral requirements (Level 2 of the fair value hierarchy). (2) Fair value of the notes payable was determined using a present value income approach based on quoted interest rates from lending institutions with which the Company would enter into similar transactions (Level 2 of the fair value hierarchy). (3) ABF Freight’s multiemployer pension plan obligation with the New England Teamsters and Trucking Industry Pension Fund (the “New England Pension Fund”) was restructured under a transition agreement effective on August 1, 2018, which resulted in a related withdrawal liability. The fair value of the outstanding withdrawal liability is equal to the present value of the future withdrawal liability payments, discounted at an interest rate of 5.6% and 5.3% at March 31, 2024 and December 31, 2023, respectively, determined using the 20-year U.S. Treasury rate plus a spread (Level 2 of the fair value hierarchy). As of March 31, 2024, the outstanding withdrawal liability totaled $19.2 million, of which $0.7 million was recorded in accrued expenses, and the remaining portion was recorded in other long-term liabilities. ​ Assets and Liabilities Measured at Fair Value on a Recurring Basis ​ The following table presents the assets and liabilities that are measured at fair value on a recurring basis: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2024 ​ ​ ​ ​ ​ ​ Fair Value Measurements Using ​ ​ ​ ​ ​ ​ Quoted Prices Significant Significant ​ ​ ​ ​ ​ In Active ​ Observable ​ Unobservable ​ ​ ​ ​ ​ ​ Markets ​ Inputs ​ Inputs ​ ​ ​ Total (Level 1) (Level 2) (Level 3) ​ ​ (in thousands) ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds (1) ​ $ 32,200 ​ $ 32,200 ​ $ — ​ $ — ​ Equity, bond, and money market mutual funds held in trust related to the Voluntary Savings Plan (2) ​ 4,821 ​ 4,821 ​ — ​ — ​ Interest rate swap (3) ​ ​ 1,214 ​ ​ — ​ ​ 1,214 ​ ​ — ​ ​ ​ $ 38,235 ​ $ 37,021 ​ $ 1,214 ​ $ — ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contingent consideration (4) ​ $ 100,220 ​ $ — ​ $ — ​ $ 100,220 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2023 ​ ​ ​ ​ ​ ​ Fair Value Measurements Using ​ ​ ​ ​ ​ ​ Quoted Prices Significant Significant ​ ​ ​ ​ ​ In Active ​ Observable ​ Unobservable ​ ​ ​ ​ ​ ​ Markets ​ Inputs ​ Inputs ​ ​ ​ Total (Level 1) (Level 2) (Level 3) ​ ​ (in thousands) ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds (1) ​ $ 93,754 ​ $ 93,754 ​ $ — ​ $ — ​ Equity, bond, and money market mutual funds held in trust related to the Voluntary Savings Plan (2) ​ 4,627 ​ 4,627 ​ — ​ — ​ Interest rate swap (3) ​ ​ 1,710 ​ ​ — ​ ​ 1,710 ​ ​ — ​ ​ ​ $ 100,091 ​ $ 98,381 ​ $ 1,710 ​ $ — ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contingent consideration (4) ​ $ 92,900 ​ $ — ​ $ — ​ $ 92,900 ​ ​ (1) Included in cash and cash equivalents. (2) Nonqualified deferred compensation plan investments consist of U.S. and international equity mutual funds, government and corporate bond mutual funds, and money market funds which are held in a trust with a third-party brokerage firm. Included in other long-term assets, with a corresponding liability reported within other long-term liabilities. (3) Included in other long-term assets. The fair value of the interest rate swap was determined by discounting future cash flows and receipts based on expected interest rates observed in market interest rate curves adjusted for estimated credit valuation considerations reflecting nonperformance risk of the Company and the counterparty, which are generally considered to be in Level 3 of the fair value hierarchy. However, the Company assessed Level 3 inputs as insignificant to the valuation at March 31, 2024 and December 31, 2023 and considers the interest rate swap valuation in Level 2 of the fair value hierarchy. (4) Included as a long-term liability, based on the March 31, 2024 remeasurement as achievement of the 2024 target is not expected. As part of the Agreement and Plan of Merger (the “Merger Agreement”) of MoLo, executed on November 1, 2021, certain additional cash consideration is required to be paid by the Company based on the achievement of certain incremental targets of adjusted earnings before interest, taxes, depreciation, and amortization (“EBITDA”) for each of the years ended December 31, 2023, 2024, and 2025. The adjusted EBITDA metric was below target for 2023, resulting in no earnout payment for 2023. At 100% of the target, the cumulative additional consideration through 2025 would be $215.0 million, consisting of target earnout payments of $70.0 million and $145.0 million, including catch-up provisions, for the years ended December 31, 2024 and 2025, respectively. Possible undiscounted cash consideration could range from a total of $95.0 million at 80% of target to $455.0 million at 300% of target, as outlined in the Merger Agreement. The estimated fair value of contingent consideration is determined by assessing Level 3 inputs. The Level 3 assessments utilize a Monte Carlo simulation with inputs including scenarios of estimated revenues and adjusted EBITDA to be achieved for the applicable performance periods, volatility factors applied to the simulations, and the discount rate applied, which was 13.4% and 13.3% as of March 31, 2024 and December 31, 2023, respectively. Changes in the significant unobservable inputs might result in a significantly higher or lower fair value at the reporting date. The increase in fair value of contingent earnout consideration as of March 31, 2024, compared to December 31, 2023, primarily relates to the shorter discount period remaining until the expected payout . ​ The following table provides the changes in fair value of the liabilities measured at fair value using inputs categorized in Level 3 of the fair value hierarchy: ​ ​ ​ ​ ​ ​ ​ ​ Contingent Consideration ​ ​ ​ (in thousands) ​ Balance at December 31, 2023 ​ $ 92,900 ​ Change in fair value included in operating income ​ ​ 7,320 ​ Balance at March 31, 2024 ​ $ 100,220 ​ ​ ​ ​ Assets Measured at Fair Value on a Nonrecurring Basis ​ The Company remeasures certain assets on a nonrecurring basis upon the occurrence of certain events. In November 2021, the Company recorded an equity investment for $25.0 million in Phantom Auto, a startup provider of human-centered remote operation software, and became a lead investor in their Series B Preferred offering. The equity investment was accounted for as a nonmarketable equity security without a readily determinable value using the measurement alternative, which allowed the investment to be recorded at cost, less any impairment and adjusted for observable price changes. During the second quarter of 2023, the fair value of the Company’s investment in Phantom Auto increased by $3.7 million based on an observable price change upon the closing of Phantom Auto’s Series B-2 funding round. During the first quarter of 2024, the Company was notified that Phantom Auto was ceasing operations due to liquidity concerns from failing to secure additional funding from investors or lenders. As a result, the Company assessed the likelihood of recovering its investment as remote and recorded a pre-tax, noncash impairment charge of $28.7 million, to write off the equity investment in Phantom Auto, which was recognized below the operating income line in “Other, net” within “Other income (costs).” ​ The following table provides the change in fair value of equity investments on a nonrecurring basis using inputs categorized in Level 3 of the fair value hierarchy: ​ ​ ​ ​ ​ ​ ​ ​ Equity Investment ​ ​ (in thousands) ​ Balance at December 31, 2023 ​ $ 28,739 ​ Change in fair value included in other income ​ ​ (28,739) ​ Balance at March 31, 2024 ​ $ — ​ ​

DISCONTINUED OPERATIONS

DISCONTINUED OPERATIONS	3 Months Ended
	Mar. 31, 2024
DISCONTINUED OPERATIONS
DISCONTINUED OPERATIONS	NOTE C – DISCONTINUED OPERATIONS ​ On February 28, 2023, the Company sold FleetNet, a wholly owned subsidiary of the Company, for an initial aggregate cash purchase price of $101.1 million, which was subject to certain tax and other customary adjustments, and recorded a pre-tax gain on sale of $69.1 million, or $51.4 million, net of tax. The purchase price was adjusted during the second quarter of 2023, resulting in an aggregate adjusted cash purchase price of $100.9 million. After adjustments the total pre-tax gain recognized in 2023 and the first quarter of 2024 was $70.2 million and $0.8 million, respectively. FleetNet provided roadside repair solutions and vehicle maintenance management services for commercial and private fleets through a network of third-party service providers. The sale of FleetNet allowed the Company to focus on growing its continuing operations, as FleetNet was no longer core to the Company’s growth initiatives. The financial results of FleetNet have been accounted for as discontinued operations for all periods presented. ​ The following table summarizes the financial results from discontinued operations: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31 ​ ​ 2024 2023 ​ ​ (in thousands) ​ Revenues ​ $ — ​ $ 55,929 ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating expenses ​ ​ ​ ​ ​ ​ ​ Gain on sale of business (1) ​ ​ (806) ​ ​ (69,083) ​ Other ​ ​ — ​ ​ 54,623 ​ ​ ​ ​ (806) ​ ​ (14,460) ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating income ​ ​ 806 ​ ​ 70,389 ​ ​ ​ ​ ​ ​ ​ ​ ​ Other income, net (2) ​ ​ — ​ ​ 17 ​ ​ ​ ​ ​ ​ ​ ​ ​ Income from discontinued operations before income taxes ​ ​ 806 ​ ​ 70,406 ​ ​ ​ ​ ​ ​ ​ ​ ​ Income tax provision ​ ​ 206 ​ ​ 17,970 ​ ​ ​ ​ ​ ​ ​ ​ ​ Income from discontinued operations, net of tax ​ $ 600 ​ $ 52,436 ​ (1) The 2024 period includes the reversal of an employee-related contingent liability that expired one-year after disposition, per the purchase agreement. The 2023 period includes transaction costs of $4.4 million consisting of consulting fees, professional fees, and employee-related expenses prior to resolution of certain post-close contingencies in second quarter 2023. (2) The 2023 period includes interest expense, which is immaterial. ​ ​ Cash flows from discontinued operations of FleetNet were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31 ​ ​ 2024 2023 ​ ​ ​ (in thousands) ​ Net cash provided by operating activities (1) ​ $ — ​ $ 762 ​ Net cash used in investing activities (2) ​ ​ — ​ ​ (398) ​ Net cash used in financing activities ​ ​ — ​ ​ (472) ​ Net decrease in cash and cash equivalents ​ $ — ​ $ (108) ​ (1) The 2023 period includes depreciation and amortization expense of $0.4 million and share-based compensation expense of $0.3 million, which is included in the “Pre-tax gain on sale of discontinued operations” line of the consolidated statements of cash flows. (2) The 2023 period includes purchases of property, plant and equipment of $0.1 million. Excludes the proceeds from the sale of discontinued operations, which are included in cash flows from continuing operations. ​

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS	3 Months Ended
	Mar. 31, 2024
GOODWILL AND INTANGIBLE ASSETS
GOODWILL AND INTANGIBLE ASSETS	NOTE D – GOODWILL AND INTANGIBLE ASSETS ​ Goodwill represents the excess of cost over the fair value of net identifiable tangible and intangible assets acquired. The goodwill balance of $304.8 million at both March 31, 2024 and December 31, 2023, primarily relates to the Asset-Light segment acquisitions of MoLo and Panther. ​ Intangible assets consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2024 ​ December 31, 2023 ​ ​ Weighted-Average ​ ​ ​ ​ Accumulated ​ Net ​ ​ ​ ​ Accumulated ​ Net ​ Amortization Period Cost Amortization Value ​ Cost Amortization Value ​ ​ (in years) ​ (in thousands) ​ (in thousands) Finite-lived intangible assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Customer relationships 12 ​ $ 99,579 ​ $ 53,463 ​ $ 46,116 ​ $ 99,579 ​ $ 51,357 ​ $ 48,222 ​ Other ​ 8 ​ ​ 30,158 ​ ​ 10,634 ​ ​ 19,524 ​ ​ 30,151 ​ ​ 9,523 ​ ​ 20,628 ​ ​ 11 ​ 129,737 ​ 64,097 ​ 65,640 ​ ​ 129,730 ​ 60,880 ​ 68,850 ​ Indefinite-lived intangible asset ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Trade name N/A ​ 32,300 ​ N/A ​ 32,300 ​ ​ 32,300 ​ N/A ​ 32,300 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total intangible assets N/A ​ $ 162,037 ​ $ 64,097 ​ $ 97,940 ​ $ 162,030 ​ $ 60,880 ​ $ 101,150 ​ ​ ​ As of March 31, 2024, the future amortization for intangible assets acquired through business acquisitions were as follows: ​ ​ ​ ​ ​ ​ ​ Amortization of ​ ​ Intangible Assets ​ ​ (in thousands) ​ Remainder of 2024 ​ $ 9,598 ​ 2025 ​ 12,798 ​ 2026 ​ 8,691 ​ 2027 ​ 7,266 ​ 2028 ​ ​ 7,266 ​ Thereafter ​ ​ 20,021 ​ Total amortization ​ $ 65,640 ​ ​

INCOME TAXES

INCOME TAXES	3 Months Ended
	Mar. 31, 2024
INCOME TAXES
INCOME TAXES	NOTE E – INCOME TAXES ​ The Company’s total effective tax benefit rate was 40.3% for the three months ended March 31, 2024, due primarily to the pre-tax loss from a noncash impairment charge to write off our equity investment in Phantom Auto included in the loss from continuing operations during the first quarter of 2024. The Company’s total effective tax rate of 24.1% for the three months ended March 31, 2023 includes discontinued operations further discussed in Note C. The effective tax benefit rate from continuing operations was 37.7% for the three months ended March 31, 2024. The effective tax rate from continuing operations was 20.0% for the three months ended March 31, 2023. State tax rates vary among states and average approximately 6.0%, although some state rates are higher, and a small number of states do not impose an income tax. ​ For the three months ended March 31 2024 and 2023, the difference between the Company’s effective tax rate from continuing operations and the federal statutory rate resulted from state income taxes, nondeductible expenses, changes in the cash surrender value of life insurance, the federal alternative fuel tax credit, the federal research and development tax credit, changes in tax valuation allowances, and the tax benefit from the vesting of stock awards. ​ As of March 31, 2024, the Company’s deferred tax liabilities, which will reverse in future years, exceeded the deferred tax assets. The Company evaluated the total deferred tax assets at March 31, 2024, and concluded that, other than for certain deferred tax assets related to foreign and state tax credit carryforwards and state net operating losses, the assets did not exceed the amount for which realization is more likely than not. In making this determination, the Company considered the future reversal of existing taxable temporary differences, future taxable income, and tax planning strategies. Valuation allowances for deferred tax assets totaled $1.8 million at both March 31, 2024 and December 31, 2023. ​ During the three months ended March 31, 2024, the Company paid federal, state, and foreign income taxes of $19.1 million and received refunds of less than $0.1 million of state income taxes that were paid in prior years. For the three months ended March 31, 2023, the Company paid federal, state, and foreign income taxes of $27.7 million and received refunds of $1.6 million of federal and state income taxes that were paid in prior years. ​ Income tax expense reflected in discontinued operations, which primarily consisted of federal and state income taxes on the gain on the sale of FleetNet, was $0.2 million and $18.0 million for the three months ended March 31, 2024 and 2023, respectively, or an effective tax rate of 25.5% in each period. ​

LEASES

LEASES	3 Months Ended
	Mar. 31, 2024
LEASES
LEASES	NOTE F – LEASES ​ The Company has operating lease arrangements for certain facilities and revenue equipment used in the Asset-Based and Asset-Light segment operations and certain other facilities and office equipment. ​ The components of operating lease expense were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31 ​ ​ 2024 2023 ​ ​ (in thousands) Operating lease expense ​ $ 10,276 ​ $ 9,166 ​ Variable lease expense ​ ​ 1,681 ​ ​ 1,540 ​ Sublease income ​ ​ (646) ​ ​ (114) ​ Total operating lease expense (1) ​ $ 11,311 ​ $ 10,592 ​ (1) Operating lease expense excludes short-term leases with a term of 12 months or less. ​ The operating cash flows from operating lease activity were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31 ​ ​ 2024 2023 ​ ​ (in thousands) ​ Noncash change in operating right-of-use assets ​ $ 8,618 ​ $ 7,485 ​ Cash payments to obtain right-of-use assets ​ ​ (7,752) ​ ​ — ​ Change in operating lease liabilities ​ ​ (8,576) ​ ​ (5,915) ​ Operating right-of-use-assets and lease liabilities, net ​ $ (7,710) ​ $ 1,570 ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash paid for amounts included in the measurement of operating lease liabilities ​ $ (10,226) ​ $ (7,596) ​ ​ Maturities of operating lease liabilities at March 31, 2024, were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equipment ​ ​ ​ ​ ​ ​ Land and ​ and ​ ​ Total Structures (1) Other ​ (in thousands) ​ Remainder of 2024 ​ $ 30,278 ​ $ 30,085 ​ $ 193 ​ 2025 ​ 37,922 ​ 37,899 ​ 23 ​ 2026 ​ 34,746 ​ 34,746 ​ — ​ 2027 ​ 28,069 ​ 28,069 ​ — ​ 2028 ​ 24,584 ​ 24,584 ​ — ​ Thereafter ​ 87,556 ​ 87,556 ​ — ​ Total lease payments ​ ​ 243,155 ​ ​ 242,939 ​ ​ 216 ​ Less imputed interest ​ ​ (37,084) ​ ​ (37,081) ​ ​ (3) ​ Total ​ $ 206,071 ​ $ 205,858 ​ $ 213 ​ (1) Excludes future minimum lease payments for leases which were executed but had not yet commenced as of March 31, 2024, totaling $28.8 million, which will be paid over approximately 10 years .

LONG-TERM DEBT AND FINANCING AR

LONG-TERM DEBT AND FINANCING ARRANGEMENTS	3 Months Ended
	Mar. 31, 2024
LONG-TERM DEBT AND FINANCING ARRANGEMENTS
LONG-TERM DEBT AND FINANCING ARRANGEMENTS	NOTE G – LONG-TERM DEBT AND FINANCING ARRANGEMENTS ​ Long-Term Debt Obligations ​ Long-term debt consisted of borrowings outstanding under the Company’s revolving credit facility, which is further described in Financing Arrangements within this Note, and notes payable related to the financing of revenue equipment (tractors and trailers used primarily in Asset-Based segment operations) and certain other equipment were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31 ​ December 31 ​ ​ 2024 2023 ​ ​ (in thousands) ​ Credit Facility (interest rate of 6.6% (1) ​ $ 50,000 ​ $ 50,000 ​ Notes payable (weighted-average interest rate of 3.9% at March 31, 2024) ​ 162,171 ​ 178,938 ​ ​ ​ 212,171 ​ 228,938 ​ Less current portion ​ 63,179 ​ 66,948 ​ Long-term debt, less current portion ​ $ 148,992 ​ $ 161,990 ​ ​ (1) The interest rate swap mitigates interest rate risk by effectively converting the $50.0 million of borrowings under the Credit Facility from variable-rate interest to fixed-rate interest with a per annum rate of 1.55% based on the margin of the Credit Facility as of both March 31, 2024 and December 31, 2023. ​ ​ Scheduled maturities of long-term debt obligations as of March 31, 2024, were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Credit ​ Notes ​ ​ Total Facility (1) Payable ​ (in thousands) ​ Due in one year or less $ 71,602 $ 3,142 $ 68,460 ​ Due after one year through two years ​ 50,181 ​ 2,690 ​ 47,491 ​ Due after two years through three years ​ 38,552 ​ 2,502 ​ 36,050 ​ Due after three years through four years ​ 69,270 ​ 51,273 ​ 17,997 ​ Due after four years through five years ​ 3,433 ​ — ​ 3,433 ​ Due after five years ​ ​ — ​ ​ — ​ ​ — ​ Total payments ​ 233,038 ​ 59,607 ​ 173,431 ​ Less amounts representing interest ​ 20,867 ​ 9,607 ​ 11,260 ​ Long-term debt $ 212,171 $ 50,000 $ 162,171 ​ (1) The future interest payments included in the scheduled maturities due are calculated using variable interest rates based on the SOFR swap curve, plus the anticipated applicable margin, exclusive of payments on the interest rate swap. ​ Assets securing notes payable were included in property, plant and equipment as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31 ​ December 31 ​ ​ 2024 2023 ​ ​ (in thousands) Revenue equipment $ 300,161 $ 300,922 ​ Service, office and other equipment ​ ​ 38,138 ​ ​ 38,138 ​ Total assets securing notes payable ​ 338,299 ​ 339,060 ​ Less accumulated depreciation (1) ​ 145,630 ​ 135,305 ​ Net assets securing notes payable ​ $ 192,669 ​ $ 203,755 ​ ​ ​ (1) Depreciation of assets securing notes payable is included in depreciation expense. ​ Financing Arrangements ​ Credit Facility As of March 31, 2024, the Company has a revolving credit facility (the “Credit Facility”) under its Fourth Amended and Restated Credit Agreement (the “Credit Agreement”), with an initial maximum credit amount of $250.0 million, including a swing line facility in an aggregate amount of up to $40.0 million and a letter of credit sub-facility providing for the issuance of letters of credit up to an aggregate amount of $20.0 million. The Company may request additional revolving commitments or incremental term loans thereunder up to an aggregate amount of up to $125.0 million, subject to the satisfaction of certain additional conditions as provided in the Credit Agreement. As of March 31, 2024, the Company had available borrowing capacity of $200.0 million under the initial maximum credit amount of the Credit Facility. ​ Principal payments under the Credit Facility are due upon maturity of the facility on October 7, 2027; however, borrowings may be repaid, at the Company’s discretion, in whole or in part at any time, without penalty, subject to required notice periods and compliance with minimum prepayment amounts. In addition, the Credit Facility requires the Company to pay a fee on unused commitments. The Credit Agreement contains conditions, representations and warranties, events of default, and indemnification provisions that are customary for financings of this type, including, but not limited to, a minimum interest coverage ratio, a maximum adjusted leverage ratio, and limitations on incurrence of debt, investments, liens on assets, certain sale and leaseback transactions, transactions with affiliates, mergers, consolidations, and sales of assets. The Company was in compliance with the covenants under the Credit Agreement at March 31, 2024. ​ Interest Rate Swap As noted in the table above, the Company has an interest rate swap agreement with a $50.0 million notional amount, which will end on October 1, 2024. The Company receives floating-rate interest amounts based on one-month SOFR in exchange for fixed-rate interest payments of 0.33% throughout the remaining term of the agreement. The fair value of the interest rate swap of $1.2 million and $1.7 million was recorded in other long-term assets at March 31, 2024 and December 31, 2023, respectively. ​ The unrealized gain or loss on the interest rate swap instrument in effect at the balance sheet date was reported as a component of accumulated other comprehensive income, net of tax, in stockholders’ equity at March 31, 2024 and December 31, 2023, and the change in the unrealized gain or loss on the interest rate swap for the three months ended March 31, 2024 and 2023 was reported in other comprehensive income (loss), net of tax, in the consolidated statements of comprehensive income. The interest rate swap is subject to certain customary provisions that could allow the counterparty to request immediate settlement of the fair value liability or asset upon violation of any or all of the provisions. The Company was in compliance with all provisions of the interest rate swap agreement at March 31, 2024. ​ Accounts Receivable Securitization Program The Company’s accounts receivable securitization program, which matures on July 1, 2024, provides available cash proceeds of $50.0 million under the program and has an accordion feature allowing the Company to request additional borrowings up to $100.0 million, subject to certain conditions. ​ Under this program, certain subsidiaries of the Company continuously sell a designated pool of trade accounts receivables to a wholly owned subsidiary which, in turn, may borrow funds on a revolving basis. This wholly owned consolidated subsidiary is a separate bankruptcy-remote entity, and its assets would be available only to satisfy the claims related to the lenders’ interest in the trade accounts receivables. Borrowings under the accounts receivable securitization program bear interest based upon SOFR, plus a margin, and an annual facility fee. The securitization agreement contains representations and warranties, affirmative and negative covenants, and events of default that are customary for financings of this type, including a maximum adjusted leverage ratio covenant. The Company was in compliance with the covenants under the accounts receivable securitization program at March 31, 2024. ​ The accounts receivable securitization program includes a provision under which the Company may request, and the letter of credit issuer may issue standby letters of credit, primarily in support of workers’ compensation and third-party casualty claims liabilities in various states in which the Company is self-insured. The outstanding standby letters of credit reduce the availability of borrowings under the program. As of March 31, 2024, standby letters of credit of $16.8 million have been issued under the program, which reduced the available borrowing capacity to $33.2 million. ​ Letter of Credit Agreements and Surety Bond Programs As of March 31, 2024, the Company had letters of credit outstanding of $17.4 million (including $16.8 million issued under the accounts receivable securitization program). The Company has programs in place with multiple surety companies for the issuance of surety bonds in support of its self-insurance program. As of March 31, 2024, surety bonds outstanding related to the self-insurance program totaled $67.7 million.

STOCKHOLDERS' EQUITY

STOCKHOLDERS' EQUITY	3 Months Ended
	Mar. 31, 2024
STOCKHOLDERS' EQUITY
STOCKHOLDERS' EQUITY	NOTE H – STOCKHOLDERS’ EQUITY ​ Accumulated Other Comprehensive Income ​ Components of accumulated other comprehensive income were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31 December 31 ​ ​ 2024 2023 ​ ​ (in thousands) ​ Pre-tax amounts: ​ ​ ​ ​ ​ ​ ​ Unrecognized net periodic benefit credit ​ $ 6,564 ​ $ 6,816 ​ Interest rate swap ​ ​ 1,214 ​ ​ 1,710 ​ Foreign currency translation ​ (3,285) ​ (2,709) ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 4,493 ​ $ 5,817 ​ ​ ​ ​ ​ ​ ​ ​ ​ After-tax amounts: ​ ​ ​ ​ ​ ​ ​ Unrecognized net periodic benefit credit ​ $ 4,874 ​ $ 5,061 ​ Interest rate swap ​ ​ 897 ​ ​ 1,263 ​ Foreign currency translation ​ (2,426) ​ (2,000) ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 3,345 ​ $ 4,324 ​ ​ ​ ​ The following is a summary of the changes in accumulated other comprehensive income, net of tax, by component for the three months ended March 31, 2024 and 2023: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrecognized ​ Interest ​ Foreign ​ ​ Total Benefit Credit Swap Translation ​ ​ (in thousands) ​ Balances at December 31, 2023 ​ $ 4,324 ​ $ 5,061 ​ $ 1,263 ​ $ (2,000) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive loss before reclassifications ​ ​ (792) ​ ​ — ​ ​ (366) ​ ​ (426) ​ Amounts reclassified from accumulated other comprehensive income ​ ​ (187) ​ ​ (187) ​ ​ — ​ ​ — ​ Net current-period other comprehensive loss ​ ​ (979) ​ ​ (187) ​ ​ (366) ​ ​ (426) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balances at March 31, 2024 ​ $ 3,345 ​ $ 4,874 ​ $ 897 ​ $ (2,426) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balances at December 31, 2022 ​ $ 7,103 ​ $ 6,896 ​ $ 2,604 ​ $ (2,397) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive loss before reclassifications ​ (470) ​ — ​ ​ (452) ​ (18) ​ Amounts reclassified from accumulated other comprehensive income ​ (247) ​ (247) ​ ​ — ​ — ​ Net current-period other comprehensive loss ​ (717) ​ (247) ​ ​ (452) ​ (18) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balances at March 31, 2023 ​ $ 6,386 ​ $ 6,649 ​ $ 2,152 ​ $ (2,415) ​ ​ The following is a summary of the significant reclassifications out of accumulated other comprehensive income by component: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrecognized Net Periodic ​ ​ ​ Benefit Credit ​ ​ Three Months Ended March 31 ​ ​ 2024 2023 ​ ​ (in thousands) Amortization of net actuarial gain, pre-tax (1) ​ $ 252 ​ $ 333 ​ Tax expense ​ ​ (65) ​ (86) ​ Total, net of tax ​ $ 187 ​ $ 247 ​ ​ (1) Included in the computation of net periodic benefit credit of the Company’s supplemental benefit plan (“SBP”) and postretirement health benefit plan. ​ Dividends on Common Stock ​ The following table is a summary of dividends declared during the applicable quarter: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2024 ​ 2023 ​ ​ Per Share Amount Per Share Amount ​ ​ (in thousands, except per share data) First quarter ​ $ 0.12 ​ $ 2,828 ​ $ 0.12 ​ $ 2,915 ​ ​ On April 26, 2024, the Company announced its Board of Directors declared a dividend of $0.12 per share to stockholders of record as of May 10, 2024. ​ Treasury Stock ​ The Company has a program to repurchase its common stock in the open market or in privately negotiated transactions (the “share repurchase program”). The share repurchase program has no expiration date but may be terminated at any time at the Board of Directors’ discretion. Repurchases may be made using the Company’s cash reserves or other available sources. ​ As of December 31, 2023, the Company had $33.5 million available for repurchases of its common stock in total under the share repurchase program. In February 2024, the Board of Directors reauthorized the share repurchase program and increased the total amount available for purchases of the Company’s common stock under the program to $125.0 million. ​ During the three months ended March 31, 2024, the Company repurchased 120,681 shares for an aggregate cost of $15.7 million, including 65,366 shares for an aggregate cost of $8.0 million under Rule 10b5-1 plans, which allows for stock repurchases during closed trading windows. The Company had $115.3 million remaining under its share repurchase program as of March 31, 2024. Subsequent to March 31, 2024 through April 30, 2024, the Company settled repurchases of 36,547 shares for an aggregate cost of $5.2 million.

EARNINGS PER SHARE

EARNINGS PER SHARE	3 Months Ended
	Mar. 31, 2024
EARNINGS PER SHARE
EARNINGS PER SHARE	NOTE I – EARNINGS PER SHARE ​ The following table sets forth the computation of basic and diluted earnings per common share: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31 ​ ​ 2024 2023 ​ ​ (in thousands, except share and per share data) ​ Basic ​ ​ ​ ​ ​ ​ ​ Numerator: ​ ​ ​ ​ ​ ​ ​ Net income (loss) from continuing operations ​ $ (2,912) ​ $ 18,847 ​ Net income from discontinued operations ​ 600 ​ 52,436 ​ Net income (loss) ​ $ (2,312) ​ $ 71,283 ​ Denominator: ​ ​ ​ ​ ​ ​ ​ Weighted-average shares ​ 23,561,309 ​ 24,288,138 ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic earnings per common share ​ ​ ​ ​ ​ ​ ​ Continuing operations ​ $ (0.12) ​ $ 0.78 ​ Discontinued operations ​ 0.03 ​ 2.16 ​ Total basic earnings per common share (1) ​ $ (0.10) ​ $ 2.93 ​ ​ ​ ​ ​ ​ ​ ​ ​ Diluted ​ ​ ​ ​ ​ ​ ​ Numerator: ​ ​ ​ ​ ​ ​ ​ Net income (loss) from continuing operations ​ $ (2,912) ​ $ 18,847 ​ Net income from discontinued operations ​ 600 ​ 52,436 ​ Net income (loss) ​ $ (2,312) ​ $ 71,283 ​ Denominator: ​ ​ ​ ​ ​ ​ ​ Weighted-average shares ​ 23,561,309 ​ 24,288,138 ​ Effect of dilutive securities ​ — ​ 769,588 ​ Adjusted weighted-average shares and assumed conversions ​ 23,561,309 ​ 25,057,726 ​ ​ ​ ​ ​ ​ ​ ​ ​ Diluted earnings per common share ​ ​ ​ ​ ​ ​ ​ Continuing operations ​ $ (0.12) ​ $ 0.75 ​ Discontinued operations ​ 0.03 ​ 2.09 ​ Total diluted earnings per common share (1) ​ $ (0.10) ​ $ 2.84 ​ ​ (1) Earnings per common share is calculated in total and may not equal the sum of earnings per common share from continuing operations and discontinued operations due to rounding.

OPERATING SEGMENT DATA

OPERATING SEGMENT DATA	3 Months Ended
	Mar. 31, 2024
OPERATING SEGMENT DATA
OPERATING SEGMENT DATA	NOTE J – OPERATING SEGMENT DATA ​ The Company uses the “management approach” to determine its reportable operating segments, as well as to determine the basis of reporting the operating segment information. The management approach focuses on financial information that the Company’s management uses to make operating decisions. Management uses revenues, operating expense categories, operating ratios, operating income (loss), and key operating statistics to evaluate performance and allocate resources to the Company’s operations. ​ On February 28, 2023, the Company sold FleetNet, a wholly owned subsidiary and reportable operating segment of the Company. Following the sale, FleetNet is reported as discontinued operations. As such, historical results of FleetNet have been excluded from both continuing operations and segment results for all periods presented. ​ The Company’s reportable operating segments are impacted by seasonal fluctuations which affect tonnage and shipment levels and demand for services, as described below; therefore, operating results for the interim periods presented may not necessarily be indicative of the results for the fiscal year. Inclement weather conditions can adversely affect freight shipments and operating costs of the Asset-Based and Asset-Light segments. Shipments may decline during winter months because of post-holiday slowdowns and during summer months due to plant shutdowns affecting automotive and manufacturing customers of the Asset-Light segment; however, weather and other disruptive events can result in higher short-term demand for expedite services depending on the impact to customers' supply chains. ​ Historically, the second and third calendar quarters of each year usually have the highest tonnage and shipment levels, while the first quarter generally has the lowest, although other factors, including the state of the U.S. and global economies; available capacity in the market; the impact of yield initiatives; and the impact of external events or conditions, may influence quarterly business levels. The Company’s yield initiatives, along with increased technology-driven intelligence and visibility with respect to demand, have allowed for shipment optimization in non-peak times, reducing the Company’s susceptibility to seasonal fluctuations in recent years, including the three months ended March 31, 2024 and 2023. ​ The Company’s reportable operating segments are as follows: ​ ● The Asset-Based segment includes the results of operations of ABF Freight System, Inc. and certain other subsidiaries. The segment operations include national, inter-regional, and regional transportation of general commodities through standard, expedited, and guaranteed LTL services. The Asset-Based segment provides services to the Asset-Light segment, including freight transportation related to managed transportation solutions and other services. ​ ● The Asset-Light segment includes the results of operations of the Company’s service offerings in truckload, ground expedite, dedicated, intermodal, household goods moving, managed transportation, warehousing and distribution, and international freight transportation for air, ocean, and ground. The Asset-Light segment provides services to the Asset-Based segment. ​ The Company’s other business activities and operations that are not reportable segments include ArcBest Corporation (the parent holding company) and certain subsidiaries. Certain costs incurred by the parent holding company and the Company’s shared services subsidiary are allocated to the reporting segments. The Company eliminates intercompany transactions in consolidation. However, the information used by the Company’s management with respect to its reportable operating segments is before intersegment eliminations of revenues and expenses. ​ Shared services represent costs incurred to support all segments, including sales, pricing, customer service, marketing, capacity sourcing functions, human resources, financial services, information technology, and other company-wide services. Certain overhead costs are not attributable to any segment and remain unallocated in “Other and eliminations.” Included in unallocated costs are expenses related to investor relations, legal, the Company’s Board of Directors, and certain technology investments. Shared services costs attributable to the reportable operating segments are predominantly allocated based upon estimated and planned resource utilization-related metrics, such as estimated shipment levels or number of personnel supported. The bases for such charges are modified and adjusted by management when necessary or appropriate to reflect fairly and equitably the actual incidence of cost incurred by the reportable operating segments. Management believes the methods used to allocate expenses are reasonable. ​ Further classifications of operations or revenues by geographic location are impracticable and, therefore, are not provided. The Company’s foreign operations are not significant. ​ The following tables reflect the Company’s reportable operating segment information from continuing operations: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31 ​ ​ 2024 2023 ​ ​ (in thousands) ​ REVENUES ​ ​ ​ ​ ​ ​ ​ Asset-Based ​ $ 671,467 ​ $ 697,817 Asset-Light ​ 396,363 ​ 438,092 ​ Other and eliminations ​ (31,411) ​ (29,815) ​ Total consolidated revenues $ 1,036,419 $ 1,106,094 ​ ​ ​ ​ ​ ​ ​ ​ OPERATING EXPENSES ​ ​ ​ ​ ​ ​ ​ Asset-Based ​ ​ ​ ​ ​ ​ ​ Salaries, wages, and benefits ​ $ 344,999 ​ $ 335,605 Fuel, supplies, and expenses ​ 81,044 ​ 94,288 ​ Operating taxes and licenses ​ 13,529 ​ 13,979 ​ Insurance ​ 14,482 ​ 13,273 ​ Communications and utilities ​ 4,799 ​ 5,304 ​ Depreciation and amortization ​ 27,007 ​ 24,911 ​ Rents and purchased transportation ​ 65,671 ​ 90,744 ​ Shared services ​ ​ 64,914 ​ ​ 64,613 ​ (Gain) loss on sale of property and equipment ​ 149 ​ (51) ​ Innovative technology costs (1) ​ — ​ 6,068 ​ Other ​ 1,417 ​ 1,612 ​ Total Asset-Based ​ 618,011 ​ 650,346 ​ ​ ​ ​ ​ ​ ​ ​ ​ Asset-Light ​ ​ ​ ​ ​ ​ ​ Purchased transportation ​ 344,122 ​ 370,163 ​ Salaries, wages, and benefits (2) ​ ​ 30,304 ​ 34,894 ​ Supplies and expenses (2) ​ 2,809 ​ 3,629 ​ Depreciation and amortization (3) ​ 5,078 ​ 5,068 ​ Shared services (2) ​ ​ 16,274 ​ ​ 16,535 ​ Contingent consideration (4) ​ ​ 7,320 ​ ​ 15,040 ​ Other (2) ​ ​ 5,714 ​ 6,854 ​ Total Asset-Light ​ 411,621 ​ 452,183 ​ ​ ​ ​ ​ ​ ​ ​ ​ Other and eliminations ​ (15,648) ​ (17,594) Total consolidated operating expenses ​ $ 1,013,984 ​ $ 1,084,935 ​ (1) Represents costs associated with the freight handling pilot test program at ABF Freight, for which the decision was made to pause the pilot during third quarter 2023. (2) For the 2023 period, certain expenses have been reclassed to conform to the current year presentation, including amounts previously reported in “Shared services” that were reclassed to present “Salaries, wages, and benefits” expenses in a separate line item, and certain immaterial facility rent expenses which were reclassed between line items. (3) Depreciation and amortization includes amortization of intangibles associated with acquired businesses. (4) Represents the change in fair value of the contingent earnout consideration related to the MoLo acquisition (see Note B). ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31 ​ ​ ​ 2024 2023 ​ ​ (in thousands) OPERATING INCOME (LOSS) FROM CONTINUING OPERATIONS ​ ​ ​ ​ ​ ​ ​ Asset-Based ​ $ 53,456 ​ $ 47,471 ​ Asset-Light ​ (15,258) ​ (14,091) ​ Other and eliminations ​ (15,763) ​ (12,221) ​ Total consolidated operating income ​ $ 22,435 ​ $ 21,159 ​ ​ ​ ​ ​ ​ ​ ​ ​ OTHER INCOME (COSTS) FROM CONTINUING OPERATIONS ​ ​ ​ ​ ​ ​ ​ Interest and dividend income ​ $ 3,315 ​ $ 2,933 ​ Interest and other related financing costs ​ (2,228) ​ (2,327) ​ Other, net (1) ​ (28,199) ​ 1,780 ​ Total other income (costs) ​ (27,112) ​ 2,386 ​ INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES ​ $ (4,677) ​ $ 23,545 ​ (1) The 2024 period includes a noncash impairment charge to write off the Company’s equity investment in Phantom Auto, a provider of human-centered remote operation software, which ceased operations during first quarter 2024. ​ The following table reflects information about revenues from customers and intersegment revenues: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31 ​ ​ 2024 2023 ​ ​ (in thousands) Revenues from customers ​ ​ ​ ​ ​ ​ ​ Asset-Based ​ $ 640,576 ​ $ 669,220 Asset-Light ​ 394,825 ​ 436,033 ​ Other ​ 1,018 ​ 841 ​ Total consolidated revenues $ 1,036,419 $ 1,106,094 ​ ​ ​ ​ ​ ​ ​ ​ Intersegment revenues ​ ​ ​ ​ ​ ​ ​ Asset-Based ​ $ 30,891 ​ $ 28,597 ​ Asset-Light ​ ​ 1,538 ​ ​ 2,059 ​ Other and eliminations ​ ​ (32,429) ​ ​ (30,656) ​ Total intersegment revenues ​ $ — $ — ​ ​ ​ ​ ​ ​ ​ ​ Total segment revenues ​ ​ ​ ​ ​ ​ ​ Asset-Based ​ $ 671,467 ​ $ 697,817 ​ Asset-Light ​ ​ 396,363 ​ ​ 438,092 ​ Other and eliminations ​ ​ (31,411) ​ ​ (29,815) ​ Total consolidated revenues ​ $ 1,036,419 ​ $ 1,106,094 ​ ​ The following table presents operating expenses by category on a consolidated basis: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31 ​ ​ 2024 2023 ​ (in thousands) OPERATING EXPENSES ​ ​ ​ ​ ​ ​ ​ Salaries, wages, and benefits ​ $ 439,523 ​ $ 436,982 ​ Rents, purchased transportation, and other costs of services ​ 375,319 ​ 429,605 ​ Fuel, supplies, and expenses (1) ​ 109,522 ​ 122,175 ​ Depreciation and amortization (2) ​ 36,833 ​ 35,010 ​ Contingent consideration (3) ​ ​ 7,320 ​ ​ 15,040 ​ Other (1) ​ 45,467 ​ 46,123 ​ ​ ​ $ 1,013,984 ​ $ 1,084,935 ​ (1) For the 2023 period, certain facility rent expenses have been reclassed between line items to conform to the current year presentation. Adjustments made are not material. (2) Includes amortization of intangible assets. (3) Represents the change in fair value of the contingent earnout consideration related to the MoLo acquisition (see Note B).

LEGAL PROCEEDINGS, ENVIRONMENTA

LEGAL PROCEEDINGS, ENVIRONMENTAL MATTERS, AND OTHER EVENTS	3 Months Ended
	Mar. 31, 2024
LEGAL PROCEEDINGS, ENVIRONMENTAL MATTERS, AND OTHER EVENTS
LEGAL PROCEEDINGS, ENVIRONMENTAL MATTERS, AND OTHER EVENTS	NOTE K – LEGAL PROCEEDINGS, ENVIRONMENTAL MATTERS, AND OTHER EVENTS ​ The Company is involved in various legal actions arising in the ordinary course of business. The Company maintains liability insurance against certain risks arising out of the normal course of its business, subject to certain self-insured retention limits. The Company routinely establishes and reviews the adequacy of reserves for estimated legal, environmental, and self-insurance exposures. While management believes that amounts accrued in the consolidated financial statements are adequate, estimates of these liabilities may change as circumstances develop. Considering amounts recorded, routine legal matters are not expected to have a material adverse effect on the Company’s financial condition, results of operations, or cash flows. ​ Legal Proceedings ​ In January 2023, the Company and MoLo were named as defendants in lawsuits related to an auto accident which involved a MoLo contract carrier. The accident occurred prior to the Company’s acquisition of MoLo on November 1, 2021. The Company intends to vigorously defend against these lawsuits. The Company believes that a loss related to this matter is reasonably possible. The Company cannot estimate the amount or a range of reasonably possible losses for this matter, if any, at this time; however, it is reasonably possible that such amounts could be material to the Company’s financial condition, results of operations, or cash flows. The Company will pursue recovery for its losses, if any, against all available sources, including, but not limited to, insurance and any potentially responsible third parties. ​ Environmental Matters ​ The Company’s subsidiaries store fuel for use in tractors and trucks in underground tanks at certain facilities. Maintenance of such tanks is regulated at the federal and, in most cases, state levels. The Company believes it is in substantial compliance with all such regulations. The Company’s underground storage tanks are required to have leak detection systems. The Company is not aware of any leaks from such tanks that could reasonably be expected to have a material adverse effect on the Company. ​ The Company has received notices from the Environmental Protection Agency (the “EPA”) and others that it has been identified as a potentially responsible party under the Comprehensive Environmental Response Compensation and Liability Act of 1980, exposure related to identified properties based on current environmental regulations, management’s experience with similar environmental matters, and testing performed at certain sites. ​ Other Events ​ During second quarter 2023, the Company received a Notice of Assessment from a state regarding an ongoing sales and use tax audit for the period December 1, 2018 to March 31, 2021. This notice is in addition to the February 2021 Notice of Assessment from that state pertaining to uncollected sales and use tax, including interest and penalties, for the period of September 1, 2016 to November 30, 2018. The Company does not agree with the basis of these assessments and filed an appeal for the 2023 assessment in October 2023 on the same legal basis as the appeal filed in May 2021 for the earlier assessment. The Company has previously accrued an amount related to these assessments consistent with applicable accounting guidance, but if the state prevails in its position, the Company may owe additional tax. Management does not believe the resolution of this matter will have a material adverse effect on the Company’s financial condition, results of operations, or cash flows. ​ During fourth quarter 2023, the Company tentatively settled a claim related to the classification of certain Asset-Light employees under the Fair Labor Standards Act

ORGANIZATION AND DESCRIPTION _2

ORGANIZATION AND DESCRIPTION OF THE BUSINESS AND FINANCIAL STATEMENT PRESENTATION (Policies)	3 Months Ended
	Mar. 31, 2024
ORGANIZATION AND DESCRIPTION OF THE BUSINESS AND FINANCIAL STATEMENT PRESENTATION
Financial Statement Presentation	Financial Statement Presentation ​ On February 28, 2023, the Company sold FleetNet America, Inc. (“FleetNet”), a wholly owned subsidiary and reportable operating segment of the Company, for an aggregate adjusted cash purchase price of $100.9 million, including post-closing adjustments. The sale of FleetNet ® ​ For the three months ended March 31, 2023, certain reclassifications have been made between operating expenses lines of the Asset-Light segment to conform to the current-year presentation (see Note J). There was no impact on total Asset-Light operating expenses as a result of these reclassifications. ​ The accompanying unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States and applicable rules and regulations of the Securities and Exchange Commission (the “SEC”) pertaining to interim financial information. Accordingly, these interim financial statements do not include all information or footnote disclosures required by accounting principles generally accepted in the United States for complete financial statements and, therefore, should be read in conjunction with the audited financial statements and accompanying notes included in the Company’s 2023 Annual Report on Form 10-K and other current filings with the SEC. In the opinion of management, all adjustments (which are of a normal and recurring nature) considered necessary for a fair presentation have been included. ​ The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual amounts may differ from those estimates.
Accounting Pronouncements Not Yet Adopted	​ ​ Accounting Pronouncements Not Yet Adopted ​ Accounting Standards Codification (“ASC”) Topic 280, Segment Reporting Improvements to Reportable Segment Disclosures ​ ASC Topic 740, Income Taxes Improvements to Income Tax Disclosures ​ In March 2024, the SEC adopted final rules under SEC Release Nos. 33-11275 and 33-99678, The Enhancement and Standardization of Climate-Related Disclosures for Investors ​

FINANCIAL INSTRUMENTS AND FAI_2

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2024
FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS
Schedule components of cash and cash equivalents, short term investments, and restricted funds	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31 December 31 ​ ​ 2024 ​ 2023 ​ ​ (in thousands) ​ Cash and cash equivalents ​ ​ ​ ​ ​ ​ ​ Cash deposits (1) ​ $ 140,655 ​ $ 168,472 ​ Money market funds (2) ​ 32,200 ​ 93,754 ​ Total cash and cash equivalents ​ $ 172,855 ​ $ 262,226 ​ ​ ​ ​ ​ ​ ​ ​ ​ Short-term investments ​ ​ ​ ​ ​ ​ ​ Certificates of deposit (1) ​ $ 68,065 ​ $ 67,842 ​ ​ (1) Recorded at cost plus accrued interest, which approximates fair value. (2) Recorded at fair value as determined by quoted market prices (see amounts presented in the table of financial assets and liabilities measured at fair value within this Note). ​
Schedule of fair value and carrying value disclosures of financial instruments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31 ​ December 31 ​ ​ 2024 2023 ​ ​ (in thousands) ​ ​ ​ ​ Carrying ​ Fair ​ Carrying ​ Fair ​ ​ ​ ​ Value ​ Value ​ Value ​ Value ​ Credit Facility (1) ​ $ 50,000 ​ $ 50,000 ​ $ 50,000 ​ $ 50,000 ​ Notes payable (2) ​ 162,171 ​ 159,385 ​ 178,938 ​ 177,149 ​ New England Pension Fund withdrawal liability (3) ​ ​ 19,222 ​ ​ 17,734 ​ ​ 19,402 ​ ​ 18,220 ​ ​ ​ $ 231,393 ​ $ 227,119 ​ $ 248,340 ​ $ 245,369 ​ ​ (1) The revolving credit facility (the “Credit Facility”) carries a variable interest rate based on Secured Overnight Financing Rate (“SOFR”), plus a margin, priced at market for debt instruments having similar terms and collateral requirements (Level 2 of the fair value hierarchy). (2) Fair value of the notes payable was determined using a present value income approach based on quoted interest rates from lending institutions with which the Company would enter into similar transactions (Level 2 of the fair value hierarchy). (3) ABF Freight’s multiemployer pension plan obligation with the New England Teamsters and Trucking Industry Pension Fund (the “New England Pension Fund”) was restructured under a transition agreement effective on August 1, 2018, which resulted in a related withdrawal liability. The fair value of the outstanding withdrawal liability is equal to the present value of the future withdrawal liability payments, discounted at an interest rate of 5.6% and 5.3% at March 31, 2024 and December 31, 2023, respectively, determined using the 20-year U.S. Treasury rate plus a spread (Level 2 of the fair value hierarchy). As of March 31, 2024, the outstanding withdrawal liability totaled $19.2 million, of which $0.7 million was recorded in accrued expenses, and the remaining portion was recorded in other long-term liabilities.
Schedule of financial assets and liabilities measured at fair value on a recurring basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2024 ​ ​ ​ ​ ​ ​ Fair Value Measurements Using ​ ​ ​ ​ ​ ​ Quoted Prices Significant Significant ​ ​ ​ ​ ​ In Active ​ Observable ​ Unobservable ​ ​ ​ ​ ​ ​ Markets ​ Inputs ​ Inputs ​ ​ ​ Total (Level 1) (Level 2) (Level 3) ​ ​ (in thousands) ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds (1) ​ $ 32,200 ​ $ 32,200 ​ $ — ​ $ — ​ Equity, bond, and money market mutual funds held in trust related to the Voluntary Savings Plan (2) ​ 4,821 ​ 4,821 ​ — ​ — ​ Interest rate swap (3) ​ ​ 1,214 ​ ​ — ​ ​ 1,214 ​ ​ — ​ ​ ​ $ 38,235 ​ $ 37,021 ​ $ 1,214 ​ $ — ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contingent consideration (4) ​ $ 100,220 ​ $ — ​ $ — ​ $ 100,220 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2023 ​ ​ ​ ​ ​ ​ Fair Value Measurements Using ​ ​ ​ ​ ​ ​ Quoted Prices Significant Significant ​ ​ ​ ​ ​ In Active ​ Observable ​ Unobservable ​ ​ ​ ​ ​ ​ Markets ​ Inputs ​ Inputs ​ ​ ​ Total (Level 1) (Level 2) (Level 3) ​ ​ (in thousands) ​ Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds (1) ​ $ 93,754 ​ $ 93,754 ​ $ — ​ $ — ​ Equity, bond, and money market mutual funds held in trust related to the Voluntary Savings Plan (2) ​ 4,627 ​ 4,627 ​ — ​ — ​ Interest rate swap (3) ​ ​ 1,710 ​ ​ — ​ ​ 1,710 ​ ​ — ​ ​ ​ $ 100,091 ​ $ 98,381 ​ $ 1,710 ​ $ — ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contingent consideration (4) ​ $ 92,900 ​ $ — ​ $ — ​ $ 92,900 ​ ​ (1) Included in cash and cash equivalents. (2) Nonqualified deferred compensation plan investments consist of U.S. and international equity mutual funds, government and corporate bond mutual funds, and money market funds which are held in a trust with a third-party brokerage firm. Included in other long-term assets, with a corresponding liability reported within other long-term liabilities. (3) Included in other long-term assets. The fair value of the interest rate swap was determined by discounting future cash flows and receipts based on expected interest rates observed in market interest rate curves adjusted for estimated credit valuation considerations reflecting nonperformance risk of the Company and the counterparty, which are generally considered to be in Level 3 of the fair value hierarchy. However, the Company assessed Level 3 inputs as insignificant to the valuation at March 31, 2024 and December 31, 2023 and considers the interest rate swap valuation in Level 2 of the fair value hierarchy. (4) Included as a long-term liability, based on the March 31, 2024 remeasurement as achievement of the 2024 target is not expected. As part of the Agreement and Plan of Merger (the “Merger Agreement”) of MoLo, executed on November 1, 2021, certain additional cash consideration is required to be paid by the Company based on the achievement of certain incremental targets of adjusted earnings before interest, taxes, depreciation, and amortization (“EBITDA”) for each of the years ended December 31, 2023, 2024, and 2025. The adjusted EBITDA metric was below target for 2023, resulting in no earnout payment for 2023. At 100% of the target, the cumulative additional consideration through 2025 would be $215.0 million, consisting of target earnout payments of $70.0 million and $145.0 million, including catch-up provisions, for the years ended December 31, 2024 and 2025, respectively. Possible undiscounted cash consideration could range from a total of $95.0 million at 80% of target to $455.0 million at 300% of target, as outlined in the Merger Agreement. The estimated fair value of contingent consideration is determined by assessing Level 3 inputs. The Level 3 assessments utilize a Monte Carlo simulation with inputs including scenarios of estimated revenues and adjusted EBITDA to be achieved for the applicable performance periods, volatility factors applied to the simulations, and the discount rate applied, which was 13.4% and 13.3% as of March 31, 2024 and December 31, 2023, respectively. Changes in the significant unobservable inputs might result in a significantly higher or lower fair value at the reporting date. The increase in fair value of contingent earnout consideration as of March 31, 2024, compared to December 31, 2023, primarily relates to the shorter discount period remaining until the expected payout .
Schedule of changes in fair value of liabilities measured at fair value using inputs categorized in Level 3	​ ​ ​ ​ ​ ​ ​ ​ Contingent Consideration ​ ​ ​ (in thousands) ​ Balance at December 31, 2023 ​ $ 92,900 ​ Change in fair value included in operating income ​ ​ 7,320 ​ Balance at March 31, 2024 ​ $ 100,220 ​
Schedule of assets measured at fair value on a nonrecurring basis	​ ​ ​ ​ ​ ​ ​ ​ Equity Investment ​ ​ (in thousands) ​ Balance at December 31, 2023 ​ $ 28,739 ​ Change in fair value included in other income ​ ​ (28,739) ​ Balance at March 31, 2024 ​ $ — ​ ​

DISCONTINUED OPERATIONS (Tables

DISCONTINUED OPERATIONS (Tables)	3 Months Ended
	Mar. 31, 2024
FleetNet | Discontinued Operations, Disposed of by Sale
Discontinued Operations
Schedules of Discontinued Operations	The following table summarizes the financial results from discontinued operations: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31 ​ ​ 2024 2023 ​ ​ (in thousands) ​ Revenues ​ $ — ​ $ 55,929 ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating expenses ​ ​ ​ ​ ​ ​ ​ Gain on sale of business (1) ​ ​ (806) ​ ​ (69,083) ​ Other ​ ​ — ​ ​ 54,623 ​ ​ ​ ​ (806) ​ ​ (14,460) ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating income ​ ​ 806 ​ ​ 70,389 ​ ​ ​ ​ ​ ​ ​ ​ ​ Other income, net (2) ​ ​ — ​ ​ 17 ​ ​ ​ ​ ​ ​ ​ ​ ​ Income from discontinued operations before income taxes ​ ​ 806 ​ ​ 70,406 ​ ​ ​ ​ ​ ​ ​ ​ ​ Income tax provision ​ ​ 206 ​ ​ 17,970 ​ ​ ​ ​ ​ ​ ​ ​ ​ Income from discontinued operations, net of tax ​ $ 600 ​ $ 52,436 ​ (1) The 2024 period includes the reversal of an employee-related contingent liability that expired one-year after disposition, per the purchase agreement. The 2023 period includes transaction costs of $4.4 million consisting of consulting fees, professional fees, and employee-related expenses prior to resolution of certain post-close contingencies in second quarter 2023. (2) The 2023 period includes interest expense, which is immaterial. ​ ​ Cash flows from discontinued operations of FleetNet were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31 ​ ​ 2024 2023 ​ ​ ​ (in thousands) ​ Net cash provided by operating activities (1) ​ $ — ​ $ 762 ​ Net cash used in investing activities (2) ​ ​ — ​ ​ (398) ​ Net cash used in financing activities ​ ​ — ​ ​ (472) ​ Net decrease in cash and cash equivalents ​ $ — ​ $ (108) ​ (1) The 2023 period includes depreciation and amortization expense of $0.4 million and share-based compensation expense of $0.3 million, which is included in the “Pre-tax gain on sale of discontinued operations” line of the consolidated statements of cash flows. (2) The 2023 period includes purchases of property, plant and equipment of $0.1 million. Excludes the proceeds from the sale of discontinued operations, which are included in cash flows from continuing operations. ​

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS (Tables)	3 Months Ended
	Mar. 31, 2024
GOODWILL AND INTANGIBLE ASSETS
Schedule of intangible assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2024 ​ December 31, 2023 ​ ​ Weighted-Average ​ ​ ​ ​ Accumulated ​ Net ​ ​ ​ ​ Accumulated ​ Net ​ Amortization Period Cost Amortization Value ​ Cost Amortization Value ​ ​ (in years) ​ (in thousands) ​ (in thousands) Finite-lived intangible assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Customer relationships 12 ​ $ 99,579 ​ $ 53,463 ​ $ 46,116 ​ $ 99,579 ​ $ 51,357 ​ $ 48,222 ​ Other ​ 8 ​ ​ 30,158 ​ ​ 10,634 ​ ​ 19,524 ​ ​ 30,151 ​ ​ 9,523 ​ ​ 20,628 ​ ​ 11 ​ 129,737 ​ 64,097 ​ 65,640 ​ ​ 129,730 ​ 60,880 ​ 68,850 ​ Indefinite-lived intangible asset ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Trade name N/A ​ 32,300 ​ N/A ​ 32,300 ​ ​ 32,300 ​ N/A ​ 32,300 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total intangible assets N/A ​ $ 162,037 ​ $ 64,097 ​ $ 97,940 ​ $ 162,030 ​ $ 60,880 ​ $ 101,150 ​ ​
Schedule of future amortization for intangible assets	​ ​ ​ ​ ​ ​ ​ Amortization of ​ ​ Intangible Assets ​ ​ (in thousands) ​ Remainder of 2024 ​ $ 9,598 ​ 2025 ​ 12,798 ​ 2026 ​ 8,691 ​ 2027 ​ 7,266 ​ 2028 ​ ​ 7,266 ​ Thereafter ​ ​ 20,021 ​ Total amortization ​ $ 65,640 ​ ​

LEASES (Tables)

LEASES (Tables)	3 Months Ended
	Mar. 31, 2024
LEASES
Schedule of components of lease expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31 ​ ​ 2024 2023 ​ ​ (in thousands) Operating lease expense ​ $ 10,276 ​ $ 9,166 ​ Variable lease expense ​ ​ 1,681 ​ ​ 1,540 ​ Sublease income ​ ​ (646) ​ ​ (114) ​ Total operating lease expense (1) ​ $ 11,311 ​ $ 10,592 ​ (1) Operating lease expense excludes short-term leases with a term of 12 months or less.
Schedule of operating cash flows from operating lease activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31 ​ ​ 2024 2023 ​ ​ (in thousands) ​ Noncash change in operating right-of-use assets ​ $ 8,618 ​ $ 7,485 ​ Cash payments to obtain right-of-use assets ​ ​ (7,752) ​ ​ — ​ Change in operating lease liabilities ​ ​ (8,576) ​ ​ (5,915) ​ Operating right-of-use-assets and lease liabilities, net ​ $ (7,710) ​ $ 1,570 ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash paid for amounts included in the measurement of operating lease liabilities ​ $ (10,226) ​ $ (7,596) ​
Schedule of maturities of operating lease liabilities	Maturities of operating lease liabilities at March 31, 2024, were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equipment ​ ​ ​ ​ ​ ​ Land and ​ and ​ ​ Total Structures (1) Other ​ (in thousands) ​ Remainder of 2024 ​ $ 30,278 ​ $ 30,085 ​ $ 193 ​ 2025 ​ 37,922 ​ 37,899 ​ 23 ​ 2026 ​ 34,746 ​ 34,746 ​ — ​ 2027 ​ 28,069 ​ 28,069 ​ — ​ 2028 ​ 24,584 ​ 24,584 ​ — ​ Thereafter ​ 87,556 ​ 87,556 ​ — ​ Total lease payments ​ ​ 243,155 ​ ​ 242,939 ​ ​ 216 ​ Less imputed interest ​ ​ (37,084) ​ ​ (37,081) ​ ​ (3) ​ Total ​ $ 206,071 ​ $ 205,858 ​ $ 213 ​ (1) Excludes future minimum lease payments for leases which were executed but had not yet commenced as of March 31, 2024, totaling $28.8 million, which will be paid over approximately 10 years .

LONG-TERM DEBT AND FINANCING _2

LONG-TERM DEBT AND FINANCING ARRANGEMENTS (Tables)	3 Months Ended
	Mar. 31, 2024
LONG-TERM DEBT AND FINANCING ARRANGEMENTS
Schedule of long-term debt	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31 ​ December 31 ​ ​ 2024 2023 ​ ​ (in thousands) ​ Credit Facility (interest rate of 6.6% (1) ​ $ 50,000 ​ $ 50,000 ​ Notes payable (weighted-average interest rate of 3.9% at March 31, 2024) ​ 162,171 ​ 178,938 ​ ​ ​ 212,171 ​ 228,938 ​ Less current portion ​ 63,179 ​ 66,948 ​ Long-term debt, less current portion ​ $ 148,992 ​ $ 161,990 ​ ​ (1) The interest rate swap mitigates interest rate risk by effectively converting the $50.0 million of borrowings under the Credit Facility from variable-rate interest to fixed-rate interest with a per annum rate of 1.55% based on the margin of the Credit Facility as of both March 31, 2024 and December 31, 2023. ​ ​
Scheduled maturities of long-term debt obligations	Scheduled maturities of long-term debt obligations as of March 31, 2024, were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Credit ​ Notes ​ ​ Total Facility (1) Payable ​ (in thousands) ​ Due in one year or less $ 71,602 $ 3,142 $ 68,460 ​ Due after one year through two years ​ 50,181 ​ 2,690 ​ 47,491 ​ Due after two years through three years ​ 38,552 ​ 2,502 ​ 36,050 ​ Due after three years through four years ​ 69,270 ​ 51,273 ​ 17,997 ​ Due after four years through five years ​ 3,433 ​ — ​ 3,433 ​ Due after five years ​ ​ — ​ ​ — ​ ​ — ​ Total payments ​ 233,038 ​ 59,607 ​ 173,431 ​ Less amounts representing interest ​ 20,867 ​ 9,607 ​ 11,260 ​ Long-term debt $ 212,171 $ 50,000 $ 162,171 ​ (1) The future interest payments included in the scheduled maturities due are calculated using variable interest rates based on the SOFR swap curve, plus the anticipated applicable margin, exclusive of payments on the interest rate swap.
Schedule of assets securing notes payable	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31 ​ December 31 ​ ​ 2024 2023 ​ ​ (in thousands) Revenue equipment $ 300,161 $ 300,922 ​ Service, office and other equipment ​ ​ 38,138 ​ ​ 38,138 ​ Total assets securing notes payable ​ 338,299 ​ 339,060 ​ Less accumulated depreciation (1) ​ 145,630 ​ 135,305 ​ Net assets securing notes payable ​ $ 192,669 ​ $ 203,755 ​ ​ ​ (1) Depreciation of assets securing notes payable is included in depreciation expense. ​

STOCKHOLDERS' EQUITY (Tables)

STOCKHOLDERS' EQUITY (Tables)	3 Months Ended
	Mar. 31, 2024
STOCKHOLDERS' EQUITY
Components of accumulated other comprehensive income	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31 December 31 ​ ​ 2024 2023 ​ ​ (in thousands) ​ Pre-tax amounts: ​ ​ ​ ​ ​ ​ ​ Unrecognized net periodic benefit credit ​ $ 6,564 ​ $ 6,816 ​ Interest rate swap ​ ​ 1,214 ​ ​ 1,710 ​ Foreign currency translation ​ (3,285) ​ (2,709) ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 4,493 ​ $ 5,817 ​ ​ ​ ​ ​ ​ ​ ​ ​ After-tax amounts: ​ ​ ​ ​ ​ ​ ​ Unrecognized net periodic benefit credit ​ $ 4,874 ​ $ 5,061 ​ Interest rate swap ​ ​ 897 ​ ​ 1,263 ​ Foreign currency translation ​ (2,426) ​ (2,000) ​ ​ ​ ​ ​ ​ ​ ​ ​ Total ​ $ 3,345 ​ $ 4,324 ​
Summary of changes in accumulated other comprehensive income, net of tax, by component	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrecognized ​ Interest ​ Foreign ​ ​ Total Benefit Credit Swap Translation ​ ​ (in thousands) ​ Balances at December 31, 2023 ​ $ 4,324 ​ $ 5,061 ​ $ 1,263 ​ $ (2,000) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive loss before reclassifications ​ ​ (792) ​ ​ — ​ ​ (366) ​ ​ (426) ​ Amounts reclassified from accumulated other comprehensive income ​ ​ (187) ​ ​ (187) ​ ​ — ​ ​ — ​ Net current-period other comprehensive loss ​ ​ (979) ​ ​ (187) ​ ​ (366) ​ ​ (426) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balances at March 31, 2024 ​ $ 3,345 ​ $ 4,874 ​ $ 897 ​ $ (2,426) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balances at December 31, 2022 ​ $ 7,103 ​ $ 6,896 ​ $ 2,604 ​ $ (2,397) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive loss before reclassifications ​ (470) ​ — ​ ​ (452) ​ (18) ​ Amounts reclassified from accumulated other comprehensive income ​ (247) ​ (247) ​ ​ — ​ — ​ Net current-period other comprehensive loss ​ (717) ​ (247) ​ ​ (452) ​ (18) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balances at March 31, 2023 ​ $ 6,386 ​ $ 6,649 ​ $ 2,152 ​ $ (2,415) ​ ​
Summary of the significant reclassifications out of accumulated other comprehensive income (loss) by component	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Unrecognized Net Periodic ​ ​ ​ Benefit Credit ​ ​ Three Months Ended March 31 ​ ​ 2024 2023 ​ ​ (in thousands) Amortization of net actuarial gain, pre-tax (1) ​ $ 252 ​ $ 333 ​ Tax expense ​ ​ (65) ​ (86) ​ Total, net of tax ​ $ 187 ​ $ 247 ​ ​ (1) Included in the computation of net periodic benefit credit of the Company’s supplemental benefit plan (“SBP”) and postretirement health benefit plan. ​
Summary of dividends declared	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2024 ​ 2023 ​ ​ Per Share Amount Per Share Amount ​ ​ (in thousands, except per share data) First quarter ​ $ 0.12 ​ $ 2,828 ​ $ 0.12 ​ $ 2,915 ​

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	3 Months Ended
	Mar. 31, 2024
EARNINGS PER SHARE
Schedule of computation of basic and diluted earnings (loss) per share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31 ​ ​ 2024 2023 ​ ​ (in thousands, except share and per share data) ​ Basic ​ ​ ​ ​ ​ ​ ​ Numerator: ​ ​ ​ ​ ​ ​ ​ Net income (loss) from continuing operations ​ $ (2,912) ​ $ 18,847 ​ Net income from discontinued operations ​ 600 ​ 52,436 ​ Net income (loss) ​ $ (2,312) ​ $ 71,283 ​ Denominator: ​ ​ ​ ​ ​ ​ ​ Weighted-average shares ​ 23,561,309 ​ 24,288,138 ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic earnings per common share ​ ​ ​ ​ ​ ​ ​ Continuing operations ​ $ (0.12) ​ $ 0.78 ​ Discontinued operations ​ 0.03 ​ 2.16 ​ Total basic earnings per common share (1) ​ $ (0.10) ​ $ 2.93 ​ ​ ​ ​ ​ ​ ​ ​ ​ Diluted ​ ​ ​ ​ ​ ​ ​ Numerator: ​ ​ ​ ​ ​ ​ ​ Net income (loss) from continuing operations ​ $ (2,912) ​ $ 18,847 ​ Net income from discontinued operations ​ 600 ​ 52,436 ​ Net income (loss) ​ $ (2,312) ​ $ 71,283 ​ Denominator: ​ ​ ​ ​ ​ ​ ​ Weighted-average shares ​ 23,561,309 ​ 24,288,138 ​ Effect of dilutive securities ​ — ​ 769,588 ​ Adjusted weighted-average shares and assumed conversions ​ 23,561,309 ​ 25,057,726 ​ ​ ​ ​ ​ ​ ​ ​ ​ Diluted earnings per common share ​ ​ ​ ​ ​ ​ ​ Continuing operations ​ $ (0.12) ​ $ 0.75 ​ Discontinued operations ​ 0.03 ​ 2.09 ​ Total diluted earnings per common share (1) ​ $ (0.10) ​ $ 2.84 ​ ​ (1) Earnings per common share is calculated in total and may not equal the sum of earnings per common share from continuing operations and discontinued operations due to rounding.

OPERATING SEGMENT DATA (Tables)

OPERATING SEGMENT DATA (Tables)	3 Months Ended
	Mar. 31, 2024
OPERATING SEGMENT DATA
Schedule of reportable operating segment information from continuing operations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31 ​ ​ 2024 2023 ​ ​ (in thousands) ​ REVENUES ​ ​ ​ ​ ​ ​ ​ Asset-Based ​ $ 671,467 ​ $ 697,817 Asset-Light ​ 396,363 ​ 438,092 ​ Other and eliminations ​ (31,411) ​ (29,815) ​ Total consolidated revenues $ 1,036,419 $ 1,106,094 ​ ​ ​ ​ ​ ​ ​ ​ OPERATING EXPENSES ​ ​ ​ ​ ​ ​ ​ Asset-Based ​ ​ ​ ​ ​ ​ ​ Salaries, wages, and benefits ​ $ 344,999 ​ $ 335,605 Fuel, supplies, and expenses ​ 81,044 ​ 94,288 ​ Operating taxes and licenses ​ 13,529 ​ 13,979 ​ Insurance ​ 14,482 ​ 13,273 ​ Communications and utilities ​ 4,799 ​ 5,304 ​ Depreciation and amortization ​ 27,007 ​ 24,911 ​ Rents and purchased transportation ​ 65,671 ​ 90,744 ​ Shared services ​ ​ 64,914 ​ ​ 64,613 ​ (Gain) loss on sale of property and equipment ​ 149 ​ (51) ​ Innovative technology costs (1) ​ — ​ 6,068 ​ Other ​ 1,417 ​ 1,612 ​ Total Asset-Based ​ 618,011 ​ 650,346 ​ ​ ​ ​ ​ ​ ​ ​ ​ Asset-Light ​ ​ ​ ​ ​ ​ ​ Purchased transportation ​ 344,122 ​ 370,163 ​ Salaries, wages, and benefits (2) ​ ​ 30,304 ​ 34,894 ​ Supplies and expenses (2) ​ 2,809 ​ 3,629 ​ Depreciation and amortization (3) ​ 5,078 ​ 5,068 ​ Shared services (2) ​ ​ 16,274 ​ ​ 16,535 ​ Contingent consideration (4) ​ ​ 7,320 ​ ​ 15,040 ​ Other (2) ​ ​ 5,714 ​ 6,854 ​ Total Asset-Light ​ 411,621 ​ 452,183 ​ ​ ​ ​ ​ ​ ​ ​ ​ Other and eliminations ​ (15,648) ​ (17,594) Total consolidated operating expenses ​ $ 1,013,984 ​ $ 1,084,935 ​ (1) Represents costs associated with the freight handling pilot test program at ABF Freight, for which the decision was made to pause the pilot during third quarter 2023. (2) For the 2023 period, certain expenses have been reclassed to conform to the current year presentation, including amounts previously reported in “Shared services” that were reclassed to present “Salaries, wages, and benefits” expenses in a separate line item, and certain immaterial facility rent expenses which were reclassed between line items. (3) Depreciation and amortization includes amortization of intangibles associated with acquired businesses. (4) Represents the change in fair value of the contingent earnout consideration related to the MoLo acquisition (see Note B). ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31 ​ ​ ​ 2024 2023 ​ ​ (in thousands) OPERATING INCOME (LOSS) FROM CONTINUING OPERATIONS ​ ​ ​ ​ ​ ​ ​ Asset-Based ​ $ 53,456 ​ $ 47,471 ​ Asset-Light ​ (15,258) ​ (14,091) ​ Other and eliminations ​ (15,763) ​ (12,221) ​ Total consolidated operating income ​ $ 22,435 ​ $ 21,159 ​ ​ ​ ​ ​ ​ ​ ​ ​ OTHER INCOME (COSTS) FROM CONTINUING OPERATIONS ​ ​ ​ ​ ​ ​ ​ Interest and dividend income ​ $ 3,315 ​ $ 2,933 ​ Interest and other related financing costs ​ (2,228) ​ (2,327) ​ Other, net (1) ​ (28,199) ​ 1,780 ​ Total other income (costs) ​ (27,112) ​ 2,386 ​ INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES ​ $ (4,677) ​ $ 23,545 ​ (1) The 2024 period includes a noncash impairment charge to write off the Company’s equity investment in Phantom Auto, a provider of human-centered remote operation software, which ceased operations during first quarter 2024. ​
Schedule of revenues from customers and intersegment revenues	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31 ​ ​ 2024 2023 ​ ​ (in thousands) Revenues from customers ​ ​ ​ ​ ​ ​ ​ Asset-Based ​ $ 640,576 ​ $ 669,220 Asset-Light ​ 394,825 ​ 436,033 ​ Other ​ 1,018 ​ 841 ​ Total consolidated revenues $ 1,036,419 $ 1,106,094 ​ ​ ​ ​ ​ ​ ​ ​ Intersegment revenues ​ ​ ​ ​ ​ ​ ​ Asset-Based ​ $ 30,891 ​ $ 28,597 ​ Asset-Light ​ ​ 1,538 ​ ​ 2,059 ​ Other and eliminations ​ ​ (32,429) ​ ​ (30,656) ​ Total intersegment revenues ​ $ — $ — ​ ​ ​ ​ ​ ​ ​ ​ Total segment revenues ​ ​ ​ ​ ​ ​ ​ Asset-Based ​ $ 671,467 ​ $ 697,817 ​ Asset-Light ​ ​ 396,363 ​ ​ 438,092 ​ Other and eliminations ​ ​ (31,411) ​ ​ (29,815) ​ Total consolidated revenues ​ $ 1,036,419 ​ $ 1,106,094 ​
Schedule of consolidated operating expenses by component	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ ​ March 31 ​ ​ 2024 2023 ​ (in thousands) OPERATING EXPENSES ​ ​ ​ ​ ​ ​ ​ Salaries, wages, and benefits ​ $ 439,523 ​ $ 436,982 ​ Rents, purchased transportation, and other costs of services ​ 375,319 ​ 429,605 ​ Fuel, supplies, and expenses (1) ​ 109,522 ​ 122,175 ​ Depreciation and amortization (2) ​ 36,833 ​ 35,010 ​ Contingent consideration (3) ​ ​ 7,320 ​ ​ 15,040 ​ Other (1) ​ 45,467 ​ 46,123 ​ ​ ​ $ 1,013,984 ​ $ 1,084,935 ​ (1) For the 2023 period, certain facility rent expenses have been reclassed between line items to conform to the current year presentation. Adjustments made are not material. (2) Includes amortization of intangible assets. (3) Represents the change in fair value of the contingent earnout consideration related to the MoLo acquisition (see Note B).

ORGANIZATION AND DESCRIPTION _3

ORGANIZATION AND DESCRIPTION OF THE BUSINESS AND FINANCIAL STATEMENT PRESENTATION - Organization and Description of Business (Details)	3 Months Ended
	Mar. 31, 2024 segment
Organization and description of business
Number of reportable operating segments	2
Asset Based
Organization and description of business
Percentage of the Company's revenues, before other revenues and intercompany eliminations, represented by the Asset-Based segment	63%
Asset Based | Unionized employees concentration risk | Number of employees
Organization and description of business
Percentage of Asset-Based segment employees covered under collective bargaining agreement with the IBT	82%

ORGANIZATION AND DESCRIPTION _4

ORGANIZATION AND DESCRIPTION OF THE BUSINESS AND FINANCIAL STATEMENT PRESENTATION - Financial Statement Presentation (Details) - USD ($) $ in Millions	Jun. 30, 2023	Feb. 28, 2023
FleetNet | Discontinued Operations, Disposed of by Sale
Discontinued Operations
Aggregate adjusted cash purchase price	$ 100.9	$ 100.9

FINANCIAL INSTRUMENTS AND FAI_3

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS - Cash and Cash Equivalents and Short-term Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair value disclosure
Cash and cash equivalents	$ 172,855	$ 262,226
Short-term investments	68,065	67,842
Concentrations of Credit Risk of Financial Instruments
Cash deposits and short-term investments which were not FDIC insured	60,000	76,300
Cash deposits
Fair value disclosure
Cash and cash equivalents	140,655	168,472
Money market funds
Fair value disclosure
Cash and cash equivalents	32,200	93,754
Certificates of deposit
Fair value disclosure
Short-term investments	$ 68,065	$ 67,842

FINANCIAL INSTRUMENTS AND FAI_4

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS - Financial instruments (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Fair value disclosure
Outstanding withdrawal liability	$ 19,200
Accrued expenses
Fair value disclosure
Outstanding withdrawal liability	700
Carrying Value
Fair value disclosure
Financial instruments	231,393	$ 248,340
Fair Value | Level 2
Fair value disclosure
Financial instruments	227,119	245,369
Credit Facility | Carrying Value
Fair value disclosure
Financial instruments	50,000	50,000
Credit Facility | Fair Value | Level 2
Fair value disclosure
Financial instruments	50,000	50,000
Notes payable | Carrying Value
Fair value disclosure
Financial instruments	162,171	178,938
Notes payable | Fair Value | Level 2
Fair value disclosure
Financial instruments	159,385	177,149
New England Pension Fund withdrawal liability | Carrying Value
Fair value disclosure
Financial instruments	19,222	19,402
New England Pension Fund withdrawal liability | Fair Value | Level 2
Fair value disclosure
Financial instruments	$ 17,734	$ 18,220
Measurement input	0.056	0.053
Financial Instrument, Measurement Input	us-gaap:MeasurementInputDiscountRateMember	us-gaap:MeasurementInputDiscountRateMember

FINANCIAL INSTRUMENTS AND FAI_5

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS - Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Liabilities:
Contingent consideration, noncurrent	$ 100,220	$ 92,900
Recurring basis
Assets:
Assets	38,235	100,091
Recurring basis | Cash and cash equivalents
Assets:
Money market funds	32,200	93,754
Recurring basis | Other long-term assets
Assets:
Equity, bond, and money market mutual funds held in trust related to the Voluntary Savings Plan	4,821	4,627
Interest rate swap	1,214	1,710
Recurring basis | Other long-term liabilities
Liabilities:
Contingent consideration, noncurrent	100,220	92,900
Recurring basis | Level 1
Assets:
Assets	37,021	98,381
Recurring basis | Level 1 | Cash and cash equivalents
Assets:
Money market funds	32,200	93,754
Recurring basis | Level 1 | Other long-term assets
Assets:
Equity, bond, and money market mutual funds held in trust related to the Voluntary Savings Plan	4,821	4,627
Recurring basis | Level 2
Assets:
Assets	1,214	1,710
Recurring basis | Level 2 | Other long-term assets
Assets:
Interest rate swap	1,214	1,710
Recurring basis | Level 3 | Other long-term liabilities
Liabilities:
Contingent consideration, noncurrent	$ 100,220	$ 92,900

FINANCIAL INSTRUMENTS AND FAI_6

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS - Merger Agreement (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)	Mar. 31, 2024	Nov. 01, 2021 USD ($)
Contingent consideration | Level 3 | Recurring basis
Fair value measurement
Measurement input	0.133	0.134
Business Combination, Contingent Consideration, Liability, Measurement Input	us-gaap:MeasurementInputDiscountRateMember	us-gaap:MeasurementInputDiscountRateMember
MoLo Solutions, LLC
Fair value measurement
Earnout payment	$ 0
MoLo Solutions, LLC | 100% of target
Fair value measurement
Adjusted EBITDA target percentage			100%
Contingent consideration, target			$ 215
Contingent consideration, target earnout payment for 2024			70
Contingent consideration, target earnout payment for 2025			$ 145
MoLo Solutions, LLC | 80% of target
Fair value measurement
Adjusted EBITDA target percentage			80%
Contingent consideration, low range			$ 95
MoLo Solutions, LLC | 300% of target
Fair value measurement
Adjusted EBITDA target percentage			300%
Contingent consideration, high range			$ 455

FINANCIAL INSTRUMENTS AND FAI_7

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS - Changes in Fair Value of Liabilities (Details) - Contingent Consideration $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Changes in fair value
Balance at beginning of period	$ 92,900
Change in fair value included in operating income	$ 7,320
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income	Operating income
Balance at end of period	$ 100,220

FINANCIAL INSTRUMENTS AND FAI_8

FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS - Assets Measured at Fair Value on a Nonrecurring Basis (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Jun. 30, 2023	Dec. 31, 2023	Nov. 30, 2021
FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS
Equity investments, Balance			$ 28,739	$ 25,000
Change in fair value included in other income, increase		$ 3,700
Change in fair value included in other income, decrease	$ (28,739)

DISCONTINUED OPERATIONS - Finan

DISCONTINUED OPERATIONS - Financial results (Details) - USD ($) $ in Thousands		3 Months Ended		12 Months Ended
	Feb. 28, 2023	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Jun. 30, 2023
Discontinued Operations
Gain on sale of discontinued operations, pre-tax		$ 806	$ 69,083
Operating expenses
Gain on sale of business		(806)	(69,083)
Income tax provision		200	18,000
Income from discontinued operations, net of tax		600	52,436
FleetNet | Discontinued Operations, Disposed of by Sale
Discontinued Operations
Aggregate purchase price	$ 101,100
Gain on sale of discontinued operations, pre-tax	69,100	806	69,083	$ 70,200
Gain on sale of business, net of tax	(51,400)
Aggregate adjusted cash purchase price	100,900				$ 100,900
Financial results from discontinued operations
Revenues			55,929
Operating expenses
Gain on sale of business	$ (69,100)	(806)	(69,083)	$ (70,200)
Other			54,623
Operating expenses		(806)	(14,460)
Operating Income		806	70,389
Other income, net			17
Income from discontinued operations before income taxes		806	70,406
Income tax provision		206	17,970
Income from discontinued operations, net of tax		$ 600	52,436
Transaction costs			$ 4,400

DISCONTINUED OPERATIONS - Cash

DISCONTINUED OPERATIONS - Cash flows (Details) - FleetNet - Discontinued Operations, Disposed of by Sale $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Cash flows from discontinued operations
Net cash provided by operating activities	$ 762
Net cash used in investing activities	(398)
Net cash used in financing activities	(472)
Net decrease in cash and cash equivalents	(108)
Depreciation and amortization expense	400
Share-based compensation expense	300
Purchases of property, plant and equipment	$ 100

GOODWILL AND INTANGIBLE ASSET_2

GOODWILL AND INTANGIBLE ASSETS - Goodwill (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Goodwill by reportable operating segment
Goodwill	$ 304,753	$ 304,753

GOODWILL AND INTANGIBLE ASSET_3

GOODWILL AND INTANGIBLE ASSETS - Intangible assets (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Finite-lived intangible assets
Weighted Average Amortization Period	11 years
Cost	$ 129,737	$ 129,730
Accumulated Amortization	64,097	60,880
Net Value	65,640	68,850
Total intangible assets
Cost	162,037	162,030
Net Value	97,940	101,150
Trade name
Indefinite-lived intangible asset
Net Value	$ 32,300	32,300
Customer relationships
Finite-lived intangible assets
Weighted Average Amortization Period	12 years
Cost	$ 99,579	99,579
Accumulated Amortization	53,463	51,357
Net Value	$ 46,116	48,222
Other intangible assets
Finite-lived intangible assets
Weighted Average Amortization Period	8 years
Cost	$ 30,158	30,151
Accumulated Amortization	10,634	9,523
Net Value	$ 19,524	$ 20,628

GOODWILL AND INTANGIBLE ASSET_4

GOODWILL AND INTANGIBLE ASSETS - Amortization (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Future amortization for intangible assets
Remainder of 2024	$ 9,598
2025	12,798
2026	8,691
2027	7,266
2028	7,266
Thereafter	20,021
Net Value	$ 65,640	$ 68,850

INCOME TAXES - Tax Rate (Detail

INCOME TAXES - Tax Rate (Details)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income taxes
Effective tax (benefit) rate, including discontinued operations (as a percent)	(40.30%)	24.10%
Effective tax (benefit) rate from continuing operations (as a percent)	(37.70%)	20%
Average state tax rate (as a percent)	6%	6%

INCOME TAXES - Allowance (Detai

INCOME TAXES - Allowance (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Deferred tax assets:
Valuation allowance	$ 1.8	$ 1.8

INCOME TAXES - Taxes Paid (Deta

INCOME TAXES - Taxes Paid (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income taxes
Income tax expense (benefit), discontinued operations	$ 0.2	$ 18
Effective tax rate, discontinued operations (as a percent)	25.50%	25.50%
Federal, state and foreign
Income taxes
Income taxes paid (in dollars)	$ 19.1	$ 27.7
State | Maximum
Income taxes
Income tax refunds received (in dollars)	$ 0.1
Federal and state
Income taxes
Income tax refunds received (in dollars)		$ 1.6

LEASES - Components of Lease Ex

LEASES - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
LEASES
Operating lease expense	$ 10,276	$ 9,166
Variable lease expense	1,681	1,540
Sublease income	(646)	(114)
Total operating lease expense	$ 11,311	$ 10,592

LEASES - Cash Flows (Details)

LEASES - Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating leases
Noncash change in operating right-of-use assets	$ 8,618	$ 7,485
Cash payments to obtain right-of-use assets	(7,752)
Change in operating lease liabilities	(8,576)	(5,915)
Operating right-of-use assets and lease liabilities, net	(7,710)	1,570
Cash paid for amounts included in the measurement of operating lease liabilities	$ (10,226)	$ (7,596)

LEASES - Maturities of Operatin

LEASES - Maturities of Operating Lease Liabilities (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Maturities of operating lease liabilities
Remainder of 2024	$ 30,278
2025	37,922
2026	34,746
2027	28,069
2028	24,584
Thereafter	87,556
Total lease payments	243,155
Less imputed interest	(37,084)
Total operating lease liabilities	$ 206,071
Operating Lease, Liability, Statement of Financial Position	Operating Lease, Liability, Current, Operating Lease, Liability, Noncurrent
Land And Structures
Maturities of operating lease liabilities
Remainder of 2024	$ 30,085
2025	37,899
2026	34,746
2027	28,069
2028	24,584
Thereafter	87,556
Total lease payments	242,939
Less imputed interest	(37,081)
Total operating lease liabilities	205,858
Future minimum payments for leases that have not yet commenced	$ 28,800
Lease term for lease commitments that have not yet commenced	10 years
Equipment and Other
Maturities of operating lease liabilities
Remainder of 2024	$ 193
2025	23
Total lease payments	216
Less imputed interest	(3)
Total operating lease liabilities	$ 213

LONG-TERM DEBT AND FINANCING _3

LONG-TERM DEBT AND FINANCING ARRANGEMENTS - Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Long-term debt obligations
Long-term debt	$ 212,171	$ 228,938
Less current portion	63,179	66,948
Long-term debt, less current portion	148,992	161,990
Credit Facility
Long-term debt obligations
Long-term debt	$ 50,000	50,000
Interest rate (as a percent)	6.60%
Credit Facility | Interest rate swap agreement, maturing on October 1, 2024
Long-term debt obligations
Amount of borrowings covered by the interest rate swap	$ 50,000	$ 50,000
Effective fixed interest rate on hedged borrowings (as a percent)	1.55%	1.55%
Notes payable
Long-term debt obligations
Long-term debt	$ 162,171	$ 178,938
Weighted-average interest rate (as a percent)	3.90%

LONG-TERM DEBT AND FINANCING _4

LONG-TERM DEBT AND FINANCING ARRANGEMENTS - Maturities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Maturities of long-term debt obligations
Due in one year or less	$ 71,602
Due after one year through two years	50,181
Due after two years through three years	38,552
Due after three years through four years	69,270
Due after four years through five years	3,433
Total payments	233,038
Less amounts representing interest	20,867
Long-term debt	212,171	$ 228,938
Credit Facility
Maturities of long-term debt obligations
Due in one year or less	3,142
Due after one year through two years	2,690
Due after two years through three years	2,502
Due after three years through four years	51,273
Total payments	59,607
Less amounts representing interest	9,607
Long-term debt	50,000	50,000
Notes payable
Maturities of long-term debt obligations
Due in one year or less	68,460
Due after one year through two years	47,491
Due after two years through three years	36,050
Due after three years through four years	17,997
Due after four years through five years	3,433
Total payments	173,431
Less amounts representing interest	11,260
Long-term debt	$ 162,171	$ 178,938

LONG-TERM DEBT AND FINANCING _5

LONG-TERM DEBT AND FINANCING ARRANGEMENTS - Assets Securing Notes (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financing Arrangements
Total assets securing notes payable	$ 338,299	$ 339,060
Less accumulated depreciation	145,630	135,305
Net assets securing notes payable	192,669	203,755
Revenue Equipment
Financing Arrangements
Total assets securing notes payable	300,161	300,922
Service, office and other equipment
Financing Arrangements
Total assets securing notes payable	$ 38,138	$ 38,138

LONG-TERM DEBT AND FINANCING _6

LONG-TERM DEBT AND FINANCING ARRANGEMENTS - Credit Facility (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Financing Arrangements
Repayment of debt	$ 16,767	$ 17,649
Credit Facility
Financing Arrangements
Maximum borrowing capacity	250,000
Remaining borrowing capacity	200,000
Credit Facility | Maximum
Financing Arrangements
Additional borrowing capacity that may be requested	125,000
Swing Line Facility
Financing Arrangements
Maximum borrowing capacity	40,000
Letters of Credit, Sub-Facility
Financing Arrangements
Maximum borrowing capacity	$ 20,000

LONG-TERM DEBT AND FINANCING _7

LONG-TERM DEBT AND FINANCING ARRANGEMENTS - Interest Rate Swap (Details) - Interest rate swap agreement, maturing on October 1, 2024 - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Financing Arrangements
Notional amount	$ 50
Fixed interest rate payments (as a percent)	0.33%
Other long-term assets
Financing Arrangements
Fair value of interest rate swap, asset	$ 1.2	$ 1.7

LONG-TERM DEBT AND FINANCING _8

LONG-TERM DEBT AND FINANCING ARRANGEMENTS - Securitization Program (Details) $ in Millions	Mar. 31, 2024 USD ($)
Financing Arrangements
Outstanding letters of credit	$ 17.4
Accounts receivable securitization program
Financing Arrangements
Maximum borrowing capacity	50
Additional borrowing capacity that may be requested	100
Outstanding letters of credit	16.8
Remaining borrowing capacity	$ 33.2

LONG-TERM DEBT AND FINANCING _9

LONG-TERM DEBT AND FINANCING ARRANGEMENTS - Letters of Credit & Surety Bonds (Details) $ in Millions	Mar. 31, 2024 USD ($)
Financing Arrangements
Outstanding letters of credit	$ 17.4
Accounts receivable securitization program
Financing Arrangements
Outstanding letters of credit	16.8
Surety bonds
Financing Arrangements
Outstanding surety bonds under uncollateralized bond programs	$ 67.7

STOCKHOLDERS' EQUITY - AOCI Com

STOCKHOLDERS' EQUITY - AOCI Components (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Accumulated Other Comprehensive Income
Total after-tax amount	$ 1,222,733	$ 1,242,363	$ 1,205,859	$ 1,151,401
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income
Total pre-tax amount	4,493	5,817
Total after-tax amount	3,345	4,324	6,386	7,103
Unrecognized Net Periodic Benefit Credit
Accumulated Other Comprehensive Income
Total pre-tax amount	6,564	6,816
Total after-tax amount	4,874	5,061	6,649	6,896
Interest Rate Swap
Accumulated Other Comprehensive Income
Total pre-tax amount	1,214	1,710
Total after-tax amount	897	1,263	2,152	2,604
Foreign Currency Translation
Accumulated Other Comprehensive Income
Total pre-tax amount	(3,285)	(2,709)
Total after-tax amount	$ (2,426)	$ (2,000)	$ (2,415)	$ (2,397)

STOCKHOLDERS' EQUITY - AOCI Cha

STOCKHOLDERS' EQUITY - AOCI Changes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Changes in accumulated other comprehensive income, net of tax, by component
Balances	$ 1,242,363	$ 1,151,401
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(979)	(717)
Balances	1,222,733	1,205,859
Accumulated Other Comprehensive Income
Changes in accumulated other comprehensive income, net of tax, by component
Balances	4,324	7,103
Other comprehensive loss before reclassifications	(792)	(470)
Amounts reclassified from accumulated other comprehensive income	(187)	(247)
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(979)	(717)
Balances	3,345	6,386
Unrecognized Net Periodic Benefit Credit
Changes in accumulated other comprehensive income, net of tax, by component
Balances	5,061	6,896
Amounts reclassified from accumulated other comprehensive income	(187)	(247)
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(187)	(247)
Balances	4,874	6,649
Interest Rate Swap
Changes in accumulated other comprehensive income, net of tax, by component
Balances	1,263	2,604
Other comprehensive loss before reclassifications	(366)	(452)
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(366)	(452)
Balances	897	2,152
Foreign Currency Translation
Changes in accumulated other comprehensive income, net of tax, by component
Balances	(2,000)	(2,397)
Other comprehensive loss before reclassifications	(426)	(18)
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(426)	(18)
Balances	$ (2,426)	$ (2,415)

STOCKHOLDERS' EQUITY - Reclass

STOCKHOLDERS' EQUITY - Reclass (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Unrecognized Net Periodic Benefit Credit
Significant reclassifications out of accumulated other comprehensive loss by component
Tax expense	$ (65)	$ (86)
Total, net of tax	187	247
Amortization of net actuarial gain
Significant reclassifications out of accumulated other comprehensive loss by component
Total, pre-tax	$ 252	$ 333

STOCKHOLDERS' EQUITY - Dividend

STOCKHOLDERS' EQUITY - Dividends (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
	Apr. 26, 2024	Mar. 31, 2024	Mar. 31, 2023
Dividends on Common Stock
Dividends declared (in dollars per share)		$ 0.12	$ 0.12
Dividend Amount		$ 2,828	$ 2,915
Subsequent Event
Dividends on Common Stock
Dividends declared (in dollars per share)	$ 0.12

STOCKHOLDERS' EQUITY - Treasury

STOCKHOLDERS' EQUITY - Treasury Stock (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Apr. 30, 2024	Mar. 31, 2024	Mar. 31, 2023	Feb. 29, 2024	Dec. 31, 2023
Treasury Stock
Cost of repurchased shares		$ 15,652	$ 14,092
Stock Repurchase Program
Treasury Stock
Amount available for repurchase		$ 115,300			$ 33,500
Amount of stock repurchases authorized				$ 125,000
Number of shares repurchased during the period		120,681
Cost of repurchased shares		$ 15,700
Stock repurchase, 10b5-1 Agreement 1
Treasury Stock
Number of shares repurchased during the period		65,366
Cost of repurchased shares		$ 8,000
Stock repurchase, 10b5-1 Agreement 2 | Subsequent Event
Treasury Stock
Number of shares repurchased during the period	36,547
Cost of repurchased shares	$ 5,200

EARNINGS PER SHARE - Basic And

EARNINGS PER SHARE - Basic And Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Basic, numerator:
Net income (loss) from continuing operations	$ (2,912)	$ 18,847
Net income from discontinued operations	600	52,436
Net income (loss)	$ (2,312)	$ 71,283
Basic, denominator:
Weighted-average shares	23,561,309	24,288,138
Basic earnings per common share
Continuing operations (in dollars per share)	$ (0.12)	$ 0.78
Discontinued operations (in dollars per share)	0.03	2.16
BASIC EARNINGS PER COMMON SHARE (in dollars per share)	$ (0.10)	$ 2.93
Diluted, numerator:
Net income (loss) from continuing operations	$ (2,912)	$ 18,847
Net income from discontinued operations	600	52,436
Net income (loss)	$ (2,312)	$ 71,283
Diluted, denominator:
Weighted-average shares	23,561,309	24,288,138
Effect of dilutive securities		769,588
Adjusted weighted-average shares and assumed conversions	23,561,309	25,057,726
Diluted earnings per common share
Continuing operations (in dollars per share)	$ (0.12)	$ 0.75
Discontinued operations (in dollars per share)	0.03	2.09
DILUTED EARNINGS PER COMMON SHARE (in dollars per share)	$ (0.10)	$ 2.84

OPERATING SEGMENT DATA - Revenu

OPERATING SEGMENT DATA - Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
REVENUES
Revenues	$ 1,036,419	$ 1,106,094
Asset Based
REVENUES
Revenues	640,576	669,220
Asset-Light
REVENUES
Revenues	394,825	436,033
Operating Segments | Asset Based
REVENUES
Revenues	671,467	697,817
Operating Segments | Asset-Light
REVENUES
Revenues	396,363	438,092
Other and eliminations
REVENUES
Revenues	$ (31,411)	$ (29,815)

OPERATING SEGMENT DATA - Operat

OPERATING SEGMENT DATA - Operating Expenses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
OPERATING EXPENSES
Salaries, wages, and benefits	$ 439,523	$ 436,982
Fuel, supplies, and expenses	109,522	122,175
Depreciation and amortization	36,833	35,010
Contingent consideration	7,320	15,040
(Gain) loss on sale of property and equipment	217	(9)
Other	45,467	46,123
Total consolidated operating expenses	1,013,984	1,084,935
Operating Segments | Asset Based
OPERATING EXPENSES
Salaries, wages, and benefits	344,999	335,605
Fuel, supplies, and expenses	81,044	94,288
Operating taxes and licenses	13,529	13,979
Insurance	14,482	13,273
Communications and utilities	4,799	5,304
Depreciation and amortization	27,007	24,911
Rents and purchased transportation	65,671	90,744
Shared services	64,914	64,613
(Gain) loss on sale of property and equipment	149	(51)
Innovative technology costs		6,068
Other	1,417	1,612
Total consolidated operating expenses	618,011	650,346
Operating Segments | Asset-Light
OPERATING EXPENSES
Purchased transportation	344,122	370,163
Salaries, wages, and benefits	30,304	34,894
Supplies and expenses	2,809	3,629
Depreciation and amortization	5,078	5,068
Shared services	16,274	16,535
Contingent consideration	7,320	15,040
Other	5,714	6,854
Total consolidated operating expenses	411,621	452,183
Other and eliminations
OPERATING EXPENSES
Total consolidated operating expenses	$ (15,648)	$ (17,594)

OPERATING SEGMENT DATA - Oper_2

OPERATING SEGMENT DATA - Operating Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
OPERATING INCOME (LOSS) FROM CONTINUING OPERATIONS
Operating income	$ 22,435	$ 21,159
OTHER INCOME (COSTS) FROM CONTINUING OPERATIONS
Interest and dividend income	3,315	2,933
Interest and other related financing costs	(2,228)	(2,327)
Other, net	(28,199)	1,780
TOTAL OTHER INCOME (COSTS)	(27,112)	2,386
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(4,677)	23,545
Operating Segments | Asset Based
OPERATING INCOME (LOSS) FROM CONTINUING OPERATIONS
Operating income	53,456	47,471
Operating Segments | Asset-Light
OPERATING INCOME (LOSS) FROM CONTINUING OPERATIONS
Operating income	(15,258)	(14,091)
Other and eliminations
OPERATING INCOME (LOSS) FROM CONTINUING OPERATIONS
Operating income	$ (15,763)	$ (12,221)

OPERATING SEGMENT DATA - Reve_2

OPERATING SEGMENT DATA - Revenue from Customers (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
REVENUES
Revenues	$ 1,036,419	$ 1,106,094
Asset Based
REVENUES
Revenues	640,576	669,220
Asset-Light
REVENUES
Revenues	394,825	436,033
Corporate and other
REVENUES
Revenues	1,018	841
Operating Segments | Asset Based
REVENUES
Revenues	671,467	697,817
Operating Segments | Asset-Light
REVENUES
Revenues	396,363	438,092
Intersegment revenues
REVENUES
Revenues	(32,429)	(30,656)
Intersegment revenues | Asset Based
REVENUES
Revenues	30,891	28,597
Intersegment revenues | Asset-Light
REVENUES
Revenues	1,538	2,059
Other and eliminations
REVENUES
Revenues	$ (31,411)	$ (29,815)

OPERATING SEGMENT DATA - Oper_3

OPERATING SEGMENT DATA - Operating Expenses by Category (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
OPERATING EXPENSES
Salaries, wages, and benefits	$ 439,523	$ 436,982
Rents, purchased transportation, and other costs of services	375,319	429,605
Fuel, supplies, and expenses	109,522	122,175
Depreciation and amortization	36,833	35,010
Contingent consideration	7,320	15,040
Other	45,467	46,123
Total consolidated operating expenses	$ 1,013,984	$ 1,084,935

LEGAL PROCEEDINGS, ENVIRONMEN_2

LEGAL PROCEEDINGS, ENVIRONMENTAL MATTERS, AND OTHER EVENTS (Details) $ in Millions	3 Months Ended
	Dec. 31, 2023 USD ($)
Claim related to employee classification under Fair Labor Standards Act | Asset-Light
Environmental Matters and Other Events
Estimated settlement expense	$ 9.5

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (2,312)	$ 71,283

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 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