Knight-Swift Transportation (KNX) 10-Q 1 Nov 23 2023 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2023	Oct. 25, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2023
Document Transition Report	false
Entity File Number	001-35007
Entity Registrant Name	Knight-Swift Transportation Holdings Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-5589597
Entity Address, Address Line One	2002 West Wahalla Lane
Entity Address, City or Town	Phoenix
Entity Address, State or Province	AZ
Entity Address, Postal Zip Code	85027
City Area Code	602
Local Phone Number	269-2000
Title of 12(b) Security	Common Stock $0.01 Par Value
Trading Symbol	KNX
Security Exchange Name	NYSE
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		161,369,000
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001492691
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) shares in Thousands, $ in Thousands		Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents		$ 193,372	$ 196,770
Cash and cash equivalents – restricted	[1]	259,979	185,792
Restricted investments, held-to-maturity, amortized cost		1,028	7,175
Trade receivables, net of allowance for doubtful accounts of $29,144 and $22,980, respectively		971,175	842,294
Contract balance – revenue in transit		12,122	15,859
Prepaid expenses		132,594	108,081
Assets held for sale		77,008	40,602
Income tax receivable		60,211	58,974
Other current assets		53,684	38,025
Total current assets		1,761,173	1,493,572
Gross property and equipment		6,542,804	5,740,383
Less: accumulated depreciation and amortization		(2,038,345)	(1,905,340)
Property and equipment, net		4,504,459	3,835,043
Operating lease right-of-use-assets		505,795	192,358
Goodwill		3,844,252	3,519,339
Intangible assets, net		2,077,426	1,776,569
Other long-term assets		147,176	134,785
Total assets		12,840,281	10,951,666
Current liabilities:
Accounts payable		299,039	220,849
Accrued payroll and purchased transportation		183,450	171,381
Accrued liabilities		228,465	81,528
Claims accruals – current portion		442,014	311,822
Finance lease liabilities and long-term debt – current portion		434,863	71,466
Operating lease liabilities – current portion		142,543	36,961
Total current liabilities		1,730,374	894,007
Revolving line of credit		300,000	43,000
Long-term debt – less current portion		1,261,711	1,024,668
Finance lease liabilities – less current portion		320,270	344,377
Operating lease liabilities – less current portion		394,921	149,992
Accounts receivable securitization		361,681	418,561
Claims accruals – less current portion		310,075	201,838
Deferred tax liabilities		959,306	907,893
Other long-term liabilities		72,142	12,049
Total liabilities		5,710,480	3,996,385
Commitments and contingencies (Notes 7, 8, and 9)
Stockholders’ equity:
Preferred stock, par value $0.01 per share; 10,000 shares authorized; none issued		$ 0	$ 0
Preferred stock, par value (in dollars per share)		$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)		10,000	10,000
Preferred stock, shares issued (in shares)		0	0
Common stock, par value $0.01 per share; 500,000 shares authorized; 161,347 and 160,706 shares issued and outstanding as of September 30, 2023 and December 31, 2022, respectively.		$ 1,613	$ 1,607
Common stock, par value (in dollars per share)		$ 0.01	$ 0.01
Common stock, shares authorized (in shares)		500,000	500,000
Common stock, shares issued (in shares)		161,347	160,706
Common stock, shares outstanding (in shares)		161,347	160,706
Additional paid-in capital		$ 4,418,981	$ 4,392,266
Accumulated other comprehensive loss		(664)	(2,436)
Retained earnings		2,693,568	2,553,567
Total Knight-Swift stockholders' equity		7,113,498	6,945,004
Noncontrolling interest		16,303	10,277
Total stockholders’ equity		7,129,801	6,955,281
Total liabilities and stockholders’ equity		$ 12,840,281	$ 10,951,666
Common Class A [Member]
Stockholders’ equity:
Common stock, shares outstanding (in shares)		161,347	160,706
[1]Reflects cash and cash equivalents that are primarily restricted for claims payments.

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Total revenue	$ 2,019,936	$ 1,896,839	$ 5,209,847	$ 5,684,959
Operating expenses:
Salaries, wages, and benefits	710,543	559,849	1,780,522	1,645,861
Fuel	272,376	231,128	628,435	678,763
Operations and maintenance	142,913	115,918	343,604	318,525
Insurance and claims	148,865	116,493	424,210	316,769
Operating taxes and licenses	30,506	26,628	84,728	85,869
Communications	8,411	5,095	20,344	16,709
Depreciation and amortization of property and equipment	176,613	150,363	488,960	442,889
Amortization of intangibles	18,907	16,254	51,595	48,635
Rental expense	50,401	15,216	81,542	42,109
Purchased transportation	330,683	364,394	869,671	1,135,750
Impairments	0	0	0	810
Miscellaneous operating expenses	48,662	30,060	116,363	62,965
Total operating expenses	1,938,880	1,631,398	4,889,974	4,795,654
Operating income	81,056	265,441	319,873	889,305
Other (expenses) income:
Interest income	5,542	1,221	16,099	2,357
Interest expense	(39,354)	(14,679)	(86,799)	(30,704)
Other income (expenses), net	11,433	8,488	30,815	(31,493)
Total other (expenses) income, net	(22,379)	(4,970)	(39,885)	(59,840)
Income before income taxes	58,677	260,471	279,988	829,465
Income tax (benefit) expense	(1,220)	65,679	53,474	206,943
Net income	59,897	194,792	226,514	622,522
Net loss attributable to noncontrolling interest	297	3	1,290	102
Net income attributable to Knight-Swift	60,194	194,795	227,804	622,624
Other comprehensive income (loss)	152	243	1,772	(1,991)
Comprehensive income	$ 60,346	$ 195,038	$ 229,576	$ 620,633
Earnings per share:
Basic (in dollars per share)	$ 0.37	$ 1.21	$ 1.41	$ 3.82
Diluted (in dollars per share)	0.37	1.21	1.41	3.80
Dividends declared per share: (in dollars per share)	$ 0.14	$ 0.12	$ 0.42	$ 0.36
Weighted average shares outstanding:
Basic (in shares)	161,332	160,665	161,124	162,785
Diluted (in shares)	161,888	161,572	161,782	163,720
Revenue, excluding truckload and LTL fuel surcharge
Total revenue	$ 1,775,249	$ 1,649,982	$ 4,615,990	$ 4,992,391
Truckload and LTL fuel surcharge
Total revenue	$ 244,687	$ 246,857	$ 593,857	$ 692,568

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Cash flows from operating activities:
Net income	$ 59,897	$ 194,792	$ 226,514	$ 622,522
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Depreciation and amortization of property, equipment, and intangibles			540,555	491,524
Gain on sale of property and equipment			(46,628)	(73,373)
Impairments	0	0	0	810
Deferred income taxes			9,587	1,126
Non-cash lease expense			68,778	30,973
(Gain) loss on equity securities			(2,100)	51,033
Other adjustments to reconcile net income to net cash provided by operating activities			46,224	32,545
Increase (decrease) in cash resulting from changes in:
Trade receivables			84,149	(44,043)
Income tax receivable			(1,237)	(14,191)
Accounts payable			(10,495)	14,259
Accrued liabilities and claims accrual			26,599	19,207
Operating lease liabilities			(68,140)	(30,755)
Other assets and liabilities			(304)	(2,442)
Net cash provided by operating activities			873,502	1,099,195
Cash flows from investing activities:
Proceeds from maturities of held-to-maturity investments			3,620	7,506
Purchases of held-to-maturity investments			(30)	(9,594)
Proceeds from sale of property and equipment, including assets held for sale			214,234	139,545
Purchases of property and equipment			(852,677)	(496,237)
Expenditures on assets held for sale			(785)	(499)
Net cash, restricted cash, and equivalents invested in acquisitions			(458,288)	(1,291)
Other cash flows from investing activities			5,896	1,944
Net cash used in investing activities			(1,088,030)	(358,626)
Cash flows from financing activities:
Repayments of finance leases and long-term debt			(81,354)	(250,884)
Proceeds from long-term debt			250,000	0
Borrowings (repayments) on revolving lines of credit, net			257,000	(114,000)
Borrowings under accounts receivable securitization			25,000	0
Repayments of accounts receivable securitization			(82,000)	0
Proceeds from common stock issued			4,200	6,111
Repurchases of the Company's common stock			0	(299,941)
Dividends paid			(68,550)	(59,011)
Other cash flows from financing activities			(18,206)	(31,104)
Net cash provided by (used in) financing activities			286,090	(748,829)
Net increase (decrease) in cash, restricted cash, and equivalents			71,562	(8,260)
Cash, restricted cash, and equivalents at beginning of period			385,345	350,023	$ 350,023
Cash, restricted cash, and equivalents at end of period	456,907	$ 341,763	456,907	341,763	$ 385,345
Cash paid during the period for:
Interest			84,361	29,342
Income taxes			38,455	234,260
Other Significant Noncash Transactions [Line Items]
Equipment acquired included in accounts payable			19,639	4,264
Purchase price adjustment on acquisition			0	2,164
Contingent consideration associated with acquisitions and investments			174,107	1,717
U.S. Xpress assumed equity awards	$ 1,462		1,462	0
Conversion of note receivable to equity investment			12,107	0
Right-of-use assets obtained in exchange for operating lease liabilities			41,888	44,465
Property and equipment obtained in exchange for finance lease liabilities			70,051	141,374
Financing provided to independent contractors for equipment sold
Other Significant Noncash Transactions [Line Items]
Other non-cash investing and financing activities			4,285	0
Noncontrolling Interest Associated With Acquisition
Other Significant Noncash Transactions [Line Items]
Other non-cash investing and financing activities			5,178	0
Transfers from property and equipment to assets held for sale [Member]
Other Significant Noncash Transactions [Line Items]
Other non-cash investing and financing activities			136,453	45,618
Property and equipment obtained in exchange for finance lease liabilities from operating lease liabilities
Other Significant Noncash Transactions [Line Items]
Property and equipment obtained in exchange for finance lease liabilities			$ 0	$ 6,462

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) Reconciliation of Cash, Restricted Cash, and Cash Equivalents - USD ($) $ in Thousands		Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2021
Statement of Cash Flows [Abstract]
Cash and cash equivalents		$ 193,372	$ 196,770	$ 194,082	$ 261,001
Cash and cash equivalents – restricted	[1]	259,979	185,792	144,960	87,241
Other long-term assets	[1]	$ 3,556	$ 2,783	$ 2,721	$ 1,781
[1]Reflects cash and cash equivalents that are primarily restricted for claims payments.

Condensed Consolidated Statem_4

Condensed Consolidated Statement Of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent	Total Knight-Swift Equity [Member]	Noncontrolling Interest [Member]	Common Class A [Member]	Common Class A [Member] Common Stock
Beginning balance, shares at Dec. 31, 2021							165,980
Beginning balance, value at Dec. 31, 2021	$ 6,543,450	$ 4,350,913	$ 2,181,142	$ (563)	$ 6,533,152	$ 10,298		$ 1,660
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued to employees (Shares)							614
Common stock issued to employees	2,375	2,369			2,375			6
Common stock issued to the Board (Shares)							18
Common stock issued to the Board	873	873			873			0
U.S. Xpress assumed equity awards	0
Common stock issued under ESPP (Shares)							59
Common stock issued under ESPP	$ 2,863	2,862			2,863			1
Company shares repurchased (Shares)	(6,001)						(6,001)
Company shares repurchased	$ (299,941)		(299,881)		(299,941)			(60)
Shares withheld – RSU settlement	(20,504)		(20,504)		(20,504)
Employee stock-based compensation expense	$ 25,878	25,878			25,878
Dividends declared per share: (in dollars per share)	$ 0.36
Cash dividends paid and dividends accrued	$ (58,912)		(58,912)		(58,912)
Net income	622,624		622,624		622,624
Net loss attributable to noncontrolling interest	(102)					102
Net income	622,522
Other comprehensive loss	(1,991)			(1,991)	(1,991)
Ending balance, shares at Sep. 30, 2022							160,670
Ending balance, value at Sep. 30, 2022	6,816,613	4,382,895	2,424,469	(2,554)	6,806,417	10,196		1,607
Beginning balance, shares at Jun. 30, 2022							160,639
Beginning balance, value at Jun. 30, 2022	6,631,257	4,372,916	2,249,333	(2,797)	6,621,058	10,199		1,606
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued to employees (Shares)							7
Common stock issued to employees	0	0			0			0
Common stock issued under ESPP (Shares)							24
Common stock issued under ESPP	$ 1,054	1,053			1,054			1
Company shares repurchased (Shares)	0
Company shares repurchased	$ 0
Shares withheld – RSU settlement	(188)		(188)		(188)
Employee stock-based compensation expense	$ 8,926	8,926			8,926
Dividends declared per share: (in dollars per share)	$ 0.12
Cash dividends paid and dividends accrued	$ (19,471)		(19,471)		(19,471)
Net income	194,795		194,795		194,795
Net loss attributable to noncontrolling interest	(3)					3
Net income	194,792
Other comprehensive loss	243			243	243
Ending balance, shares at Sep. 30, 2022							160,670
Ending balance, value at Sep. 30, 2022	$ 6,816,613	4,382,895	2,424,469	(2,554)	6,806,417	10,196		1,607
Beginning balance, shares at Dec. 31, 2022	160,706						160,706
Beginning balance, value at Dec. 31, 2022	$ 6,955,281	4,392,266	2,553,567	(2,436)	6,945,004	10,277		1,607
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued to employees (Shares)							565
Common stock issued to employees	163	158			163			5
Common stock issued to the Board (Shares)							18
Common stock issued to the Board	977	977			977			0
U.S. Xpress assumed equity awards	1,462	1,462			1,462
Common stock issued under ESPP (Shares)							58
Common stock issued under ESPP	3,060	3,059			3,060			1
Shares withheld – RSU settlement	(19,548)		(19,548)		(19,548)
Employee stock-based compensation expense	$ 21,059	21,059			21,059
Dividends declared per share: (in dollars per share)	$ 0.42
Cash dividends paid and dividends accrued	$ (68,255)		(68,255)		(68,255)
Net income	227,804		227,804		227,804
Net loss attributable to noncontrolling interest	(1,290)					1,290
Net income	226,514
Other comprehensive loss	1,772			1,772	1,772
Investment in noncontrolling interest	7,555					7,555
Distribution to noncontrolling interest	$ (239)					(239)
Ending balance, shares at Sep. 30, 2023	161,347						161,347
Ending balance, value at Sep. 30, 2023	$ 7,129,801	4,418,981	2,693,568	(664)	7,113,498	16,303		1,613
Beginning balance, shares at Jun. 30, 2023							161,276
Beginning balance, value at Jun. 30, 2023	7,081,043	4,412,069	2,657,415	(815)	7,070,282	10,761		1,613
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued to employees (Shares)							53
Common stock issued to employees	0	0			0			0
U.S. Xpress assumed equity awards	1,462	1,462			1,462
Common stock issued under ESPP (Shares)							18
Common stock issued under ESPP	978	978			978			0
Shares withheld – RSU settlement	(1,277)		(1,277)		(1,277)
Employee stock-based compensation expense	$ 4,472	4,472			4,472
Dividends declared per share: (in dollars per share)	$ 0.14
Cash dividends paid and dividends accrued	$ (22,764)		(22,764)		(22,764)
Net income	60,194		60,194		60,194
Net loss attributable to noncontrolling interest	(297)					297
Net income	59,897
Other comprehensive loss	151			151	151
Investment in noncontrolling interest	$ 5,839					(5,839)
Ending balance, shares at Sep. 30, 2023	161,347						161,347
Ending balance, value at Sep. 30, 2023	$ 7,129,801	$ 4,418,981	$ 2,693,568	$ (664)	$ 7,113,498	$ 16,303		$ 1,613

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited)(Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Receivables [Abstract]
Parenthetical - allowance for doubtful accounts	$ 29,144	$ 22,980

Introduction and Basis of Prese

Introduction and Basis of Presentation	9 Months Ended
	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Introduction and Basis of Presentation	Introduction and Basis of Presentation Certain acronyms and terms used throughout this Quarterly Report are specific to the Company, commonly used in the trucking industry, or are otherwise frequently used throughout this document. Definitions for these acronyms and terms are provided in the "Glossary of Terms," available in the front of this document. Description of Business Knight-Swift is a transportation solutions provider, headquartered in Phoenix, Arizona. During the year-to-date period ended September 30, 2023, the Company operated an average of 20,054 tractors (comprised of 17,977 company tractors and 2,077 independent contractor tractors) and 85,125 trailers within the Truckload segment and leasing activities within the non-reportable segments. The LTL segment operated an average of 3,177 tractors and 8,445 trailers. Additionally, the Intermodal segment operated an average of 647 tractors and 12,780 intermodal containers. As of September 30, 2023, the Company's four reportable segments were Truckload, LTL, Logistics, and Intermodal. Basis of Presentation The condensed consolidated financial statements and footnotes included in this Quarterly Report include the accounts of Knight-Swift Transportation Holdings Inc. and its subsidiaries and should be read in conjunction with the consolidated financial statements and footnotes included in Knight-Swift's 2022 Annual Report. In management's opinion, these condensed consolidated financial statements were prepared in accordance with GAAP and include all adjustments necessary (consisting of normal recurring adjustments) for the fair statement of the periods presented. With respect to transactional/durational data, references to years pertain to calendar years. Similarly, references to quarters pertain to calendar quarters. Note regarding comparability — The reported results do not include U.S. Xpress's operating results prior to its acquisition by the Company on July 1, 2023 in accordance with the accounting treatment applicable to the transaction. Accordingly, comparisons between the Company's third quarter 2023 results and prior periods may not be meaningful. Seasonality In the full truckload transportation industry, results of operations generally follow a seasonal pattern. Freight volumes in the first quarter are typically lower due to less consumer demand, customers reducing shipments following the holiday season, and inclement weather. At the same time, operating expenses generally increase, and tractor productivity of the Company's Truckload fleet, independent contractors and third-party carriers decreases during the winter months due to decreased fuel efficiency, increased cold weather-related equipment maintenance and repairs, and increased insurance claims and costs attributed to higher accident frequency from harsh weather. These factors typically lead to lower operating profitability, as compared to other parts of the year. Additionally, beginning in the latter half of the third quarter and continuing into the fourth quarter, the Company typically experiences surges pertaining to holiday shopping trends toward delivery of gifts purchased over the Internet, as well as the length of the holiday season (consumer shopping days between Thanksgiving and Christmas). However, as the Company continues to diversify its business through expansion into the LTL industry, warehousing, and other activities, seasonal volatility is becoming more tempered. Additionally, macroeconomic trends and cyclical changes in the trucking industry, including imbalances in supply and demand, can override the seasonality faced in the industry.

Recently Issued Accounting Pron

Recently Issued Accounting Pronouncements	9 Months Ended
	Sep. 30, 2023
Accounting Standards Update and Change in Accounting Principle [Abstract]
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements Date Issued Reference Description Expected Adoption Date and Method Financial Statement Impact March 2023 ASU No. 2023-01: Leases (ASC 842), Common Control Arrangements The amendments in this ASU require that leasehold improvements associated with common control leases be amortized by the lessee over the useful life of the leasehold improvements and that leasehold improvements associated with common control leases be accounted for as a transfer between entities under common control through an adjustment to equity if the lessee no longer controls the use of the asset. January 2024, Prospective or retrospective Currently under evaluation, but not expected to be material July 2023 ASU No. 2023-03: Presentation of Financial Statements (ASC 205), Income Statement—Reporting Comprehensive Income (ASC 220), Distinguishing Liabilities from Equity (ASC 480), Equity (ASC 505), and Compensation—Stock Compensation (ASC 718) The amendments in this ASU reflect alignment to Staff Accounting Bulletin No. 120 ("SAB 120") that was issued by the SEC in November 2021. SAB 120 provides guidance to entities issuing share-based awards shortly before announcing material, nonpublic information. The guidance indicates that entities should consider such material nonpublic information to adjust the observable market if the effect of the release of the material nonpublic information is expected to affect the share price and the share-based awards are non-routine in nature. July 2023, prospective adoption Currently under evaluation, but not expected to be material August 2023 ASU No. 2023-05: Business Combinations — Joint Venture Formations (ASC 805-60), Recognition and Initial Measurement Requires a joint venture to initially measure all contributions received upon its formation at fair value. January 2025, prospective adoption Currently under evaluation, but not expected to be material October 2023 ASU No. 2023-06: Disclosure Improvements The amendments in this ASU updated several topics of the ASC to incorporate changes required by guidance made effective by SEC Final Rule No. 33-10532. The SEC Final Rule incorporates existing or incremental requirements of Regulation S-X into the accounting standards codification. October 2023, prospective adoption Presentation and disclosure impact only

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2023
Business Combinations [Abstract]
Acquisitions	Acquisitions U.S. Xpress On July 1, 2023, the Company acquired Chattanooga, Tennessee-based U.S. Xpress Enterprises, Inc. ("U.S. Xpress"), one of the largest asset-based truckload carriers in the United States. The acquisition was completed through a Knight-Swift subsidiary formed to hold the U.S. Xpress business post-closing ("HoldCo") with Max Fuller, former Executive Chairman of U.S. Xpress, Eric Fuller, former CEO of U.S. Xpress, and their related entities and trusts (collectively, the "Rollover Holders"), rolling over a portion of their shares of U.S. Xpress into HoldCo for approximately 10% interest in HoldCo. The total purchase price consideration of $630.0 million consisted of $454.4 million in cash, including approximately $139.8 million in debt payoffs, and $1.5 million in assumed equity related to the revaluation of equity awards. The purchase price also included contingent consideration valued at $174.1 million, consisting of two classes of membership interests in HoldCo. The Class A membership interests will be subject to put and call rights at a defined fair market value measure in favor of the Rollover Holders and the Company, respectively, and will be purchased by the Company at that defined fair market value measure if outstanding at the fifth anniversary of the acquisition date. In order for the put right to become exercisable, it is subject to a $175 million minimum adjusted operating income threshold for U.S. Xpress. In addition, the Company will have a call right, exercisable only within the first 15 months after closing, at an exercise price of approximately $140 million. The Class B membership interests will be repurchased by the Company for $40 million if U.S. Xpress achieves $250 million in adjusted operating income for a trailing annual period at or prior to the fifth anniversary of closing. If such threshold is not met, the Class B interests will be forfeited for no value. As of September 30, 2023, the $134.1 million in mandatorily redeemable Class A membership interests is included in "Accrued liabilities" in the Company's condensed consolidated balance sheets and the $40.0 million in mandatory purchase of Class B membership interest is included in "Other long-term liabilities" in the Company's condensed consolidated balance sheets, depending on the terms. Cash was funded from the 2023 Term Loan, as well as existing Knight-Swift liquidity. The purchase of the equity interests of U.S. Xpress results in the historical tax basis of U.S. Xpress' assets continuing to be recovered and any intangible assets arising through purchase accounting will result in additional stock basis for tax purposes. Deferred taxes were established as of the opening balance sheet for purchase accounting fair value adjustments (other than for goodwill). The merger agreement contained customary representations, warranties, and covenants for a transaction of this nature. During the quarter and year-to-date periods ended September 30, 2023, the Company's consolidated operating results included U.S. Xpress' total revenue of $461.6 million and a net loss of $19.9 million. U.S. Xpress' net income during quarter and year-to-date periods ended September 30, 2023 included $2.3 million related to the amortization of intangible assets acquired in the U.S. Xpress Acquisition. The goodwill recognized represents expected synergies from combining the operations of U.S. Xpress with the Company, including enhanced service offerings, as well as other intangible assets that did not meet the criteria for separate recognition. The goodwill is not expected to be deductible for tax purposes. See Note 6 for more information about the Company's credit facilities and the 2023 Term Loan. Purchase Price Allocation The purchase price allocation for U.S. Xpress is preliminary and has been allocated based on estimated fair values of the assets acquired and liabilities assumed at the acquisition date, and among other things may be pending the completion of the valuation of acquired tangible assets, an independent valuation of certain acquired intangible assets, assessment of lease agreements, assessment of certain liabilities, the calculation of deferred taxes based upon the underlying tax basis of assets acquired and liabilities assumed, and assessment of other tax related items as applicable. As the Company obtains more information, the preliminary purchase price allocation disclosed below is subject to change. Any future adjustments to the preliminary purchase price allocation, including changes within identifiable intangible assets or estimation uncertainty impacted by market conditions, may impact future net earnings. The purchase price allocation adjustments can be made through the end of the measurement period, which is not to exceed one year from the acquisition date. July 1, 2023 Opening Balance Sheet as Reported at September 30, 2023 Fair value of the consideration transferred $ 632,109 Cash and cash equivalents 3,321 Receivables 216,659 Prepaid expenses 21,347 Other current assets 47,317 Property and equipment 433,210 Operating lease right-of-use assets 337,055 Identifiable intangible assets 1 348,000 Other noncurrent assets 28,457 Total assets 1,435,366 Accounts payable (102,193) Accrued payroll and payroll-related expenses (27,485) Accrued liabilities (19,966) Claims accruals – current and noncurrent portions (180,251) Operating lease liabilities – current and noncurrent portions (376,763) Long-term debt and finance leases – current and noncurrent portions (337,949) Deferred tax liabilities (41,826) Other long-term liabilities (34,230) Total liabilities (1,120,663) Noncontrolling interest (391) Total stockholders' equity (391) Goodwill $ 317,797 1 Includes $184.5 million in customer relationships and $163.5 million in trade names. Pro Forma Information — The following unaudited pro forma information combines the historical operations of the Company and U.S. Xpress giving effect to the U.S. Xpress Acquisition, and related transactions as if consummated on January 1, 2022, the beginning of the comparative period presented. Quarter Ended September 30, Year-to-Date September 30, 2023 2022 2023 2022 (In thousands, except per share data) Total revenue $ 2,019,936 $ 2,444,667 $ 6,165,131 $ 7,303,678 Net income attributable to Knight-Swift 33,584 100,112 146,522 599,058 Earnings per share – diluted 0.21 0.62 0.91 3.66 The unaudited pro forma condensed combined financial information has been presented for comparative purposes only and includes certain adjustments such as recognition of assets acquired at estimated fair values and related depreciation and amortization, elimination of transaction costs incurred by Knight-Swift and U.S. Xpress during the periods presented that were directly related to the U.S. Xpress Acquisition, and related income tax effects of these items. As a result of the U.S. Xpress Acquisition, both Knight-Swift and U.S. Xpress incurred certain acquisition-related expenses, including professional legal and advisory fees, acceleration of share-based compensation, bonus incentives, severance payments, filing fees and other miscellaneous expenses. These acquisition-related expenses totaled $6.5 million and $31.8 million during the quarter and year-to-date periods ended September 30, 2023, respectively. These expenses were eliminated in the presentation of the unaudited pro forma "Net income attributable to Knight-Swift" presented above. The unaudited pro forma condensed combined financial information does not purport to represent the actual results of operations that Knight-Swift and U.S. Xpress would have achieved had the companies been combined during the periods presented in the unaudited pro forma condensed combined financial statements and is not intended to project the future results of operations that the combined company may achieve after the identified transactions. The unaudited pro forma condensed combined financial information does not reflect any cost savings that may be realized as a result of the U.S. Xpress Acquisition and also does not reflect any restructuring or integration-related costs to achieve those potential cost savings. The Company did not complete any other material acquisitions during the year-to-date period ended September 30, 2023.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Effective Tax Rate — The quarter ended September 30, 2023 and September 30, 2022 effective tax rates were (2.1)% and 25.2%, respectively. The Company recognized discrete items relating to a partial release of the valuation allowance associated with the U.S. Xpress net operating loss and tax credit carryforward benefits, stock compensation deductions, and a reduction in state deferred taxes due to adjustments to state tax rates and apportionment during the quarter ended September 30, 2023. The year-to-date September 30, 2023 and September 30, 2022 effective tax rates were 19.1% and 24.9%, respectively. The Company recognized discrete items relating to a partial release of the valuation allowance associated with the U.S. Xpress net operating loss and tax credit carryforward benefits, stock compensation deductions, and a reduction in state deferred taxes due to adjustments to state tax rates and apportionment during the year-to-date period ended September 30, 2023. Valuation Allowance — Valuation allowances are provided if, based upon the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. U.S. Xpress initially had a valuation allowance of $25.0 million not considering Knight-Swift entities. During the quarter, $14.6 million of that valuation allowance was released due to the Company’s ability to utilize certain tax attributes in future periods. The remaining $10.4 million valuation allowance is maintained to offset the tax benefit of capital loss and state operating loss carryforwards that may not be utilized in the future. Unrecognized Tax Benefits — Due to the acquisition, the Company has unrecognized tax benefits associated with tax credit carryforwards. Management does not expect a decrease in unrecognized tax benefits relating to credits to be necessary within the next twelve months. Interest and Penalties — The Company had no accrued interest and penalties related to unrecognized tax benefits as of September 30, 2023 . Accrued interest and penalties related to unrecognized tax benefits were approximately $0.2 million as of December 31, 2022. Tax Examinations — Certain of the Company's subsidiaries are currently under examination by various Federal and state jurisdictions for tax years ranging from 2009 to 2021 . At the completion of these examinations, management does not expect any adjustments that would have a material impact on the Company's effective tax rate. Years subsequent to 2017 remain subject to examination.

Accounts Receivable Securitizat

Accounts Receivable Securitization	9 Months Ended
	Sep. 30, 2023
Transfers and Servicing [Abstract]
Accounts Receivable Securitization	Accounts Receivable Securitization On October 3, 2022, the Company entered into the 2022 RSA, which further amended the 2021 RSA. The 2022 RSA is a secured borrowing that is collateralized by the Company's eligible receivables, for which the Company is the servicing agent. The Company's receivable originator subsidiaries sell, on a revolving basis, undivided interests in all of their eligible accounts receivable to Swift Receivables Company II, LLC ("SRCII") who in turn sells a variable percentage ownership in those receivables to the various purchasers. The Company's eligible receivables are included in "Trade receivables, net of allowance for doubtful accounts" in the consolidated balance sheets. As of September 30, 2023, the Company's eligible receivables generally have high credit quality, as determined by the obligor's corporate credit rating. The 2022 RSA is subject to fees, various affirmative and negative covenants, representations and warranties, and default and termination provisions customary for facilities of this type. The Company was in compliance with these covenants as of September 30, 2023. Collections on the underlying receivables by the Company are held for the benefit of SRCII and the various purchasers and are unavailable to satisfy claims of the Company and its subsidiaries. The following table summarizes the key terms of the 2022 RSA (dollars in thousands): 2022 RSA (Dollars in thousands) Effective date October 3, 2022 Final maturity date October 1, 2025 Borrowing capacity $475,000 Accordion option 1 $100,000 Unused commitment fee rate 2 20 to 40 basis points Program fees on outstanding balances 3 one month SOFR + credit adjustment spread 10 basis points + 82.5 basis points 1 The accordion option increases the maximum borrowing capacity, subject to participation of the purchasers. 2 The 2022 RSA commitment fee rates are based on the percentage of the maximum borrowing capacity utilized. 3 As identified within the 2022 RSA, the lender can trigger an amendment by identifying and deciding upon a replacement for SOFR. Availability under the 2022 RSA is calculated as follows: September 30, 2023 December 31, 2022 (In thousands) Borrowing base, based on eligible receivables $ 363,800 $ 456,400 Less: outstanding borrowings 1 (362,000) (419,000) Availability under accounts receivable securitization facilities $ 1,800 $ 37,400 1 Outstanding borrowings are included in "Accounts receivable securitization" in the condensed consolidated balance sheets and are offset by deferred loan costs of $0.3 million and $0.4 million as of September 30, 2023 and December 31, 2022, respectively. Interest accrued on the aggregate principal balance at a rate of 6.3% and 5.1% as of September 30, 2023 and December 31, 2022, respectively. Refer to Note 12 for information regarding the fair value of the 2022 RSA. 2023 RSA On October 23, 2023, the Company entered into the Seventh Amendment to the Amended and Restated Receivables Sales Agreement ("2023 RSA"). The 2023 RSA, among other things, increases the maximum borrowing capacity to $575.0 million.

Debt And Financing

Debt And Financing	9 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
Debt and Financing	Debt and Financing Other than the Company's accounts receivable securitization as discussed in Note 5, the Company's long-term debt consisted of the following: September 30, 2023 December 31, 2022 (In thousands) 2021 Term Loan A-2, due September 3, 2024, net 1 2 199,865 199,755 2021 Term Loan A-3, due September 3, 2026, net 1 2 798,970 798,705 2023 Term Loan, due September 3, 2026, net 1 3 249,054 — Revenue equipment installment notes 1 4 296,884 — Prudential Notes, net 1 28,057 35,960 Other 9,322 3,042 Total long-term debt, including current portion 1,582,152 1,037,462 Less: current portion of long-term debt (320,441) (12,794) Long-term debt, less current portion $ 1,261,711 $ 1,024,668 September 30, 2023 December 31, 2022 (In thousands) Total long-term debt, including current portion $ 1,582,152 $ 1,037,462 2021 Revolver, due September 3, 2026 1 5 300,000 43,000 Long-term debt, including revolving line of credit $ 1,882,152 $ 1,080,462 1 Refer to Note 12 for information regarding the fair value of debt. 2 As of September 30, 2023, the carrying amounts of the 2021 Term Loan A-2 and 2021 Term Loan A-3 were net of $0.1 million and $1.0 million in deferred loan costs, respectively. As of December 31, 2022, the carrying amounts of the 2021 Term Loan A-2 and 2021 Term Loan A-3 were net of $0.2 million and $1.3 million in deferred loan costs, respectively. 3 As of September 30, 2023, the carrying amount of the 2023 Term Loan was net of $0.9 million in deferred loan costs. 4 The revenue equipment installment loans were assumed at the close of the U. S. Xpress Acquisition and have a weighted average interest rate of 4.5% as of September 30, 2023. 5 The Company also had outstanding letters of credit of $21.2 million and $15.8 million under the 2021 Revolver, primarily related to workers' compensation and self-insurance liabilities at September 30, 2023 and December 31, 2022, respectively. The Company also had outstanding letters of credit of $264.3 million and $173.1 million under a separate bilateral agreement which do not impact the availability of the 2021 Revolver as of September 30, 2023 and December 31, 2022, respectively. Credit Agreements 2021 Debt Agreement — On September 3, 2021, the Company entered into the $2.3 billion 2021 Debt Agreement (an unsecured credit facility) with a group of banks, replacing the Company's prior debt agreements. The following table presents the key terms of the 2021 Debt Agreement: 2021 Term Loan A-2 2021 Term Loan A-3 2021 Revolver 2 2021 Debt Agreement Terms (Dollars in thousands) Maximum borrowing capacity $200,000 $800,000 $1,100,000 Final maturity date September 3, 2024 September 3, 2026 September 3, 2026 Interest rate margin reference rate BSBY BSBY BSBY Interest rate minimum margin 1 0.75% 0.88% 0.88% Interest rate maximum margin 1 1.38% 1.50% 1.50% Minimum principal payment — amount $— $10,000 $— Minimum principal payment — frequency Once Quarterly Once Minimum principal payment — commencement date September 3, 2024 September 30, 2024 September 3, 2026 1 The interest rate margin for the 2021 Term Loans and 2021 Revolver is based on the Company's consolidated leverage ratio. As of September 30, 2023, interest accrued at 6.39% on the 2021 Term Loan A-2, 6.51% on the 2021 Term Loan A-3, and 6.53% on the 2021 Revolver. 2 The commitment fee for the unused portion of the 2021 Revolver is based on the Company's consolidated leverage ratio, and ranges from 0.1% to 0.2%. As of September 30, 2023, commitment fees on the unused portion of the 2021 Revolver accrued at 0.1% and outstanding letter of credit fees accrued at 1.1%. Pursuant to the 2021 Debt Agreement, the 2021 Revolver and the 2021 Term Loans contain certain financial covenants with respect to a maximum net leverage ratio and a minimum consolidated interest coverage ratio. The 2021 Debt Agreement provides flexibility regarding the use of proceeds from asset sales, payment of dividends, stock repurchases, and equipment financing. In addition to the financial covenants, the 2021 Debt Agreement includes usual and customary events of default for a facility of this nature and provides that, upon the occurrence and continuation of an event of default, payment of all amounts payable under the 2021 Debt Agreement may be accelerated, and the lenders' commitments may be terminated. The 2021 Debt Agreement contains certain usual and customary restrictions and covenants relating to, among other things, dividends (which are restricted only if a default or event of default occurs and is continuing or would result therefrom), liens, affiliate transactions, and other indebtedness. As of September 30, 2023, the Company was in compliance with the covenants under the 2021 Debt Agreement. Borrowings under the 2021 Debt Agreement are made by Knight-Swift Transportation Holdings Inc. and are guaranteed by certain of the Company's material domestic subsidiaries (other than its captive insurance subsidiaries, driving academy subsidiary, and bankruptcy-remote special purpose subsidiary). 2023 Term Loan — On June 22, 2023, the Company entered into the $250.0 million 2023 Term Loan (an unsecured credit facility) with a group of banks. The 2023 Term Loan matures on September 3, 2026. There are no scheduled principal payments due until maturity. The 2023 Term Loan contains terms similar to the 2021 Debt Agreement. The proceeds received from the 2023 Term Loan were used to pay fees, commissions and expenses in connection with the Company's acquisition of U.S. Xpress. The interest rate applicable to the 2023 Term Loan is subject to a leverage-based grid and as of September 30, 2023 is equal to SOFR plus the 0.1% SOFR adjustment plus 1.375%. As of September 30, 2023, interest accrued at 6.79% on the 2023 Term Loan. U.S. Xpress's Revenue Equipment Installment Notes — In connection with the U.S. Xpress Acquisition, the Company assumed revenue equipment installment notes with various lenders to finance tractors and trailers. Payments are due in monthly installments with final maturities at various dates through March 15, 2028, and the notes are secured by related revenue equipment with a net book value of $256.7 million as of September 30, 2023. Payment terms generally range from 36 months to 84 months. The interest rates as of September 30, 2023 range from 2% to 7%. ACT's Prudential Notes — The 2021 Prudential Notes allow ACT to borrow up to $125.0 million, less amounts currently outstanding with Prudential Capital Group, provided that certain financial ratios are maintained. The 2021 Prudential Notes have interest rates ranging fro m 4.05% to 4.40% a nd various maturity dates ranging from October 2023 through January 2028. The 2021 Prudential Notes are unsecured and contain usual and customary restrictions on, among other things, the ability to make certain payments to stockholders, similar to the provisions of the Company's 2021 Debt Agreement. As of September 30, 2023, ACT had $98.2 million available for issuance under the agreement. Fair Value Measurement — See Note 12 for fair value disclosures regarding the Company's debt instruments.

Defined Benefit Pension Plan

Defined Benefit Pension Plan	9 Months Ended
	Sep. 30, 2023
Retirement Benefits [Abstract]
Defined Benefit Pension Plan	Defined Benefit Pension Plan Net periodic pension income and benefits paid during the quarters ended September 30, 2023 and 2022 were immaterial. Assumptions A weighted-average discount rate of 5.58% was used to determine benefit obligations as of September 30, 2023. The following weighted-average assumptions were used to determine net periodic pension cost: Quarter Ended September 30, Year-to-Date September 30, 2023 2022 2023 2022 Discount rate 4.86 % 4.33 % 4.79 % 3.13 % Expected long-term rate of return on pension plan assets 6.00 % 6.00 % 6.00 % 6.00 % Refer to Note 12 for additional information regarding fair value measurements of the Company's investments.

Purchase Commitments

Purchase Commitments	9 Months Ended
	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Purchase Commitments	Purchase Commitments As of September 30, 2023, the Company had outstanding commitments to purchase revenue equipment of $284.2 million in the remainder of 2023 ($179.7 million of which were tractor commitments), and none thereafter. These purchases may be financed through any combination of finance leases, operating leases, debt, proceeds from sales of existing equipment, and cash flows from operations. As of September 30, 2023, the Company had outstanding commitments to purchase facilities and non-revenue equipment of $49.8 million in the remainder of 2023, $19.1 million from 2024 through 2025, $2.0 million from 2026 through 2027, and none thereafter. Factors such as costs and opportunities for future terminal expansions may change the amount of such expenditures.

Contingencies and Legal Proceed

Contingencies and Legal Proceedings	9 Months Ended
	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Contingencies and Legal Proceedings	Contingencies and Legal Proceedings Legal Proceedings The Company is party to certain legal proceedings incidental to its business. The majority of these claims relate to bodily injury, property damage, cargo and workers' compensation incurred in the transportation of freight, as well as certain class action litigation related to personnel and employment matters. We record a liability when we believe that it is probable that a loss has been incurred and the amount can be reasonably estimated. Information is provided below regarding the nature, status, and contingent loss amounts, if any, associated with pending legal matters that may be material to the Company. There are inherent uncertainties in these legal matters, some of which are beyond management's control, making the ultimate outcomes difficult to predict. Moreover, management's views and estimates related to these matters may change in the future, as new events and circumstances arise and the matters continue to develop. Cash flows or results of operations could be materially affected in any particular period by the resolution of one or more of these contingencies. The Company has made accruals with respect to its legal matters where appropriate, which are included in "Accrued liabilities" in the condensed consolidated balance sheets. The Company has recorded an aggregate accrual of approximately $9.2 million, relating to the Company's outstanding legal proceedings as of September 30, 2023. EMPLOYEE COMPENSATION AND PAY PRACTICES MATTERS California Wage, Meal, and Rest Class Actions The plaintiffs generally allege one or more of the following: that the Company 1) failed to pay the California minimum wage; 2) failed to provide proper meal and rest periods; 3) failed to timely pay wages upon separation from employment; 4) failed to pay for all hours worked; 5) failed to pay overtime; 6) failed to properly reimburse work-related expenses; and 7) failed to provide accurate wage statements. Plaintiff(s) Defendant(s) Date instituted Court or agency currently pending in John Burnell 1 Swift Transportation Co., Inc March 22, 2010 United States District Court for the Central District of California James R. Rudsell 1 Swift Transportation Co. of Arizona, LLC and Swift Transportation Company April 5, 2012 United States District Court for the Central District of California Recent Developments and Current Status In April 2019, the parties reached settlement of this matter. In January 2020, the court granted final approval of the settlement. Two objectors appealed the court’s decision granting final approval of the settlement. The Company paid this settlement on July 10, 2023. California Wage and Hour Class Action Litigation - U.S. Xpress The plaintiffs generally allege one or more of the following: that class members were 1) not paid for off-the-clock work; 2) not provided duty free meal or rest breaks; 3) not paid premium pay in their absence; 4) not paid the California minimum wage for all hours worked in that state; 5) not provided accurate and complete itemized wage statements; and 6) not paid all accrued wages at the end of their employment. Plaintiff(s) Defendant(s) Date instituted Court or agency currently pending in Various U.S. Xpress December 23, 2015 United States District Court for the Central District of California Recent Developments and Current Status In February 2023, the parties reached an agreement to settle the California Wage and Hour Class Action Litigation, exclusive of employer-side taxes. On September 19, 2023, the court granted final approval of the settlement. No party objected to the settlement. The settlement amount (including employer-side taxes) is payable by November 2, 2023 and the loss has accordingly been accrued as of September 30, 2023. SHAREHOLDER MATTERS - U.S. Xpress Stockholder Derivative Action The plaintiffs generally allege that U.S. Xpress made false and/or misleading statements in the registration statement and prospectus filed with the SEC in connection with the IPO and that the Individual Defendants breached their fiduciary duties by causing or allowing U.S. Xpress to make such statements. The complaint alleges that U.S. Xpress has been damaged by the alleged wrongful conduct as a result of, among other things, being subjected to the time and expense of the securities class action lawsuits that have been filed relating to the IPO. In addition to a claim for alleged breach of fiduciary duties, the lawsuit alleges claims against the Individual Defendants for unjust enrichment, abuse of control, gross mismanagement, and waste of corporate assets. Plaintiff(s) Defendant(s) Date instituted Court or agency currently pending in Various Five executives and five independent board members of U.S. Xpress (collectively, the "Individual Defendants") June 7, 2019 District Court for Clark County, Nevada Recent Developments and Current Status The lawsuit was dismissed without prejudice on August 14, 2023. Stockholder Claims Between November 2018 and April 2019, eight substantially similar putative securities class action complaints were filed against U.S. Xpress and certain other defendants: five in the Circuit Court of Hamilton County, Tennessee (“Tennessee State Court Cases”), two in the U.S. District Court for the Eastern District of Tennessee (“Federal Court Cases”), and one in the Supreme Court of the State of New York (“New York State Court Case”). The putative class action lawsuits generally allege that U.S. Xpress made false and/or misleading statements in the registration statement and prospectus filed with the Securities and Exchange Commission (“SEC”) in connection with the June 2018 initial public offering (“IPO”). Plaintiff(s) Defendant(s) Date instituted Court or agency currently pending in Various U.S. Xpress, five officers or directors, and the seven underwriters who participated in the IPO November 2018 Circuit Court of Hamilton County, Tennessee, U.S. District Court for the Eastern District of Tennessee and Supreme Court of the State of New York SHAREHOLDER MATTERS - U.S. Xpress (Continued) Recent Developments and Current Status Tennessee State Court Cases The Consolidated Amended Class Action Complaint (the “Consolidated State Court Complaint”) filed on May 10, 2019 in the Circuit Court of Hamilton County, Tennessee against U.S. Xpress, five officers or directors, and the seven underwriters who participated in the IPO, alleges violations of Sections 11, 12(a)(2) and 15 of the Securities Act of 1933 (the “Securities Act”). The lawsuit is purportedly brought on behalf of a putative class. On November 13, 2020, the court presiding over the Tennessee State Court Cases entered an order, granting in part and denying in part the defendants’ Motions to Dismiss the Consolidated State Court Complaint. The court held that the plaintiffs failed to state a claim for violation of the Securities Act with respect to the majority of statements challenged as false or misleading in the Consolidated State Court Complaint. The court, however, held that the Consolidated State Court Complaint sufficiently alleged violations of the Securities Act with respect to one statement from the IPO registration statement and prospectus that the plaintiffs alleged to be false or misleading, both on theories of alleged misrepresentations and material omissions. New York State Court Case On March 14, 2019, a substantially similar putative class action complaint was filed in the Supreme Court of the State of New York, County of New York, by a different plaintiff alleging claims under Sections 11 and 15 of the Securities Act against the same defendants as in the Tennessee State Court Cases. On December 18, 2020, defendants filed a Motion to Dismiss or Stay the New York State Case both on the merits and in deference to the pending actions in Tennessee. On March 5, 2021, the court presiding over the New York State Case dismissed the case, and on January 13, 2022, the court entered a motion denying plaintiff’s motion for reconsideration. Federal Court Cases The operative amended complaint was filed on October 8, 2019 (“Amended Federal Complaint”), which named the same defendants as the Tennessee State Court Cases. The Amended Federal Complaint is made on behalf of a putative class. In addition to claims for alleged violations of Section 11 and 15 of the Securities Act, the Amended Federal Complaint alleges violations of Section 10(b) and 20(a) of the Securities Exchange Act of 1934 (“Exchange Act”) against U.S. Xpress, its Chief Executive Officer and its Chief Financial Officer. On June 30, 2020, the court presiding over the Federal Court Cases issued its ruling granting in part and denying in part the defendants’ Motions to Dismiss the Amended Federal Complaint. The court dismissed entirely the plaintiffs’ claims for alleged violations of the Exchange Act and further held that the plaintiffs failed to state a claim for violation of the Securities Act with respect to the majority of statements challenged as false or misleading in the Amended Federal Complaint. The court, however, held that the Federal Amended Complaint sufficiently alleged violations of the Securities Act with respect to two statements from the IPO registration statement and prospectus that the plaintiffs alleged to be false or misleading, both on theories of alleged misrepresentations and material omissions. Settlement The parties reached a settlement with the Federal Court and Tennessee State Court plaintiffs. On March 27, 2023, the parties filed the stipulation of settlement with the Federal Court, and on March 28, 2023, the Federal Court entered an order granting preliminary approval of the settlement. The Federal Court entered an order granting final approval of the settlement on July 12, 2023. The monetary component of the settlement in principle is to be paid by the applicable insurance carriers. 1 Individually and on behalf of all others similarly situated.

Share Repurchase Plans

Share Repurchase Plans	9 Months Ended
	Sep. 30, 2023
Equity [Abstract]
Share Repurchase Plans	Share Repurchase Plans On April 25, 2022, the Company announced that the Board approved the repurchase of up to $350.0 million of the Company's outstanding common stock (the "2022 Knight-Swift Share Repurchase Plan"). With the adoption of the 2022 Knight-Swift Share Repurchase Plan, the Company terminated the 2020 Knight-Swift Share Repurchase Plan, which had approximately $42.8 million of authorized purchases remaining upon termination. The Company made no share repurchases during the quarter and year-to-date periods ended September 30, 2023. $0 The following table presents the Company's repurchases of its common stock during 2022 under the respective share repurchase plans, excluding advisory fees: Share Repurchase Plan Quarter Ended September 30, 2022 Year-to-Date September 30, 2022 Board Approval Date Authorized Amount Shares Amount Shares Amount (shares and dollars in thousands) November 24, 2020 $250,000 — $ — 2,821 $ 149,982 April 19, 2022 1 $350,000 — $ — 3,180 $ 149,959 — $ — 6,001 $ 299,941 1 $200.0 million remained available under the 2022 Knight-Swift Repurchase Plan as of September 30, 2023 and December 31, 2022.

Weighted Average Shares Outstan

Weighted Average Shares Outstanding	9 Months Ended
	Sep. 30, 2023
Earnings Per Share [Abstract]
Weighted Average Shares Outstanding	Weighted Average Shares Outstanding Earnings per share, basic and diluted, as presented in the condensed consolidated statements of comprehensive income, are calculated by dividing net income attributable to Knight-Swift by the respective weighted average common shares outstanding during the period. The following table reconciles basic weighted average shares outstanding to diluted weighted average shares outstanding: Quarter Ended September 30, Year-to-Date September 30, 2023 2022 2023 2022 (In thousands) Basic weighted average common shares outstanding 161,332 160,665 161,124 162,785 Dilutive effect of equity awards 556 907 658 935 Diluted weighted average common shares outstanding 161,888 161,572 161,782 163,720 Anti-dilutive shares excluded from earnings per diluted share 1 57 132 141 321 1 Shares were excluded from the dilutive-effect calculation because the outstanding awards' exercise prices were greater than the average market price of the Company's common stock for the periods presented.

Fair Value Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurement	Fair Value Measurement The following table presents the carrying amounts and estimated fair values of the Company's major categories of financial assets and liabilities: September 30, 2023 December 31, 2022 Condensed Consolidated Balance Sheets Caption Carrying Estimated Carrying Estimated (In thousands) Financial Assets: Equity method investments Other long-term assets $ 97,878 $ 97,878 $ 103,517 $ 103,517 Investments in equity securities Other long-term assets — — 1,668 1,668 Convertible note Other current assets — — 11,341 11,341 Financial Liabilities: 2021 Term Loan A-2, due September 2024 1 Finance lease liabilities and long-term debt – current portion 199,865 200,000 199,755 200,000 2021 Term Loan A-3, due September 2026 1 Finance lease liabilities and long-term debt 798,970 800,000 798,705 800,000 2023 Term Loan, due September 2026 2 Long-term debt – less current portion 249,054 250,000 — — 2021 Revolver, due September 2026 Revolving line of credit 300,000 300,000 43,000 43,000 Revenue equipment installment notes 3 Finance lease liabilities and long-term debt 296,884 296,884 — — 2021 Prudential Notes 4 Finance lease liabilities and long-term debt 28,057 28,085 35,960 36,014 2022 RSA, due October 2025 5 Accounts receivable securitization 361,681 362,000 418,561 419,000 Mandatorily redeemable contingent consideration 6 Accrued liabilities 134,107 134,107 — — Contingent consideration 6 Accrued liabilities, Other long-term liabilities 40,859 40,859 4,217 4,217 1 As of September 30, 2023, the carrying amounts of the 2021 Term Loan A-2 and 2021 Term Loan A-3 were net of $0.1 million and $1.0 million in deferred loan costs, respectively. As of December 31, 2022, the carrying amounts of the 2021 Term Loan A-2 and 2021 Term Loan A-3 were net of $0.2 million and $1.3 million in deferred loan costs, respectively. 2 As of September 30, 2023, the carrying amount of the 2023 Term Loan was net of $0.9 million in deferred loan costs. 3 As of September 30, 2023, the carrying amount of the revenue equipment installment notes included $1.6 million in fair value adjustments. 4 As of September 30, 2023, the carrying amount of the 2021 Prudential Notes was net of approximately $28,000 i n deferred loan costs and included $1.3 million in fair value adjustments. As of December 31, 2022, the carrying amount of the 2021 Prudential Notes was net of $0.1 million in deferred loan costs and included $1.7 million in fair value adjustments. 5 The carrying amount of the 2022 RSA was net of $0.3 million and $0.4 million in deferred loan costs as of September 30, 2023 and December 31, 2022, respectively. 6 Refer to Note 3 for information regarding the contingent consideration related to the U.S. Xpress Acquisition. Recurring Fair Value Measurements (Assets) — As of September 30, 2023, the Company had no major categories of assets estimated at fair value that were measured on a recurring basis. The following table depicts the level in the fair value hierarchy of the inputs used to estimate the fair value of assets measured on a recurring basis as of December 31, 2022: Fair Value Measurements at Reporting Date Using Estimated Fair Value Level 1 Inputs Level 2 Inputs Level 3 Inputs Unrealized Gain (Loss) Position (In thousands) As of December 31, 2022 Convertible notes 1 $ 11,341 $ — $ — $ 11,341 $ 1,341 Investments in equity securities 2 1,668 1,668 — — (50,918) 1 Convertible notes — The condensed consolidated statements of comprehensive income include the fair value activities from the Company's convertible notes within "Other income (expenses), net". The estimated fair value is based on probability-weighted discounted cash flow analysis of the corresponding pay-off/redemption. • Quarter Ended Gain (Loss) Activities: The Company recognized an unrealized gain of $0.3 million during the quarter ended September 30, 2022. • Year-to-date Gain (Loss) Activities: The Company recognized an unrealized gain of $0.9 million during the year-to-date period ended September 30, 2022. 2 Investments in equity securities — The condensed consolidated statements of comprehensive income include the fair value activities from the Company's investments in equity securities within "Other income (expenses), net". The estimated fair value is based on quoted prices in active markets that are readily and regularly obtainable. • Quarter Ended Gain (Loss) Activities: During the quarter ended September 30, 2022, the Company recognized a gain of $0.5 million, which consisted of $7.0 million in realized gains from the Company's other investments in equity securities. This was partially offset by $6.5 million in unrealized losses, primarily from mark-to-market adjustments of the Company's equity investment in Embark. • Year-to-date Gain (Loss) Activities: During the year-to-date period ended September 30, 2022, the Company recognized a loss of $51.0 million, which consisted of $62.4 million in unrealized losses, primarily from mark-to-market adjustments of the Company's investment in Embark. This was partially offset by $11.4 million realized gains from the Company's other investments in equity securities. Recurring Fair Value Measurements (Liabilities) — The following table depicts the level in the fair value hierarchy of the inputs used to estimate the fair value of liabilities measured on a recurring basis as of September 30, 2023 and December 31, 2022: Fair Value Measurements at Reporting Date Using Estimated Fair Value Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Gain (Loss) (In thousands) As of September 30, 2023 Mandatorily redeemable contingent consideration 1 $ 134,107 $ — $ — $ 134,107 $ — Contingent consideration 1 2 $ 40,859 $ — $ — $ 40,859 $ 3,359 As of December 31, 2022 Contingent consideration 2 $ 4,217 $ — $ — $ 4,217 $ — 1 Refer to Note 3 for information regarding the contingent consideration related to the U.S. Xpress Acquisition. 2 Contingent consideration is associated with acquisitions and investments. The Company recognized a gain of $0.9 million during the quarter ended September 30, 2023 and a gain of $3.4 million during the year-to-date period ended September 30, 2023. The Company did not recognize any gains (losses) in the quarter and year-to-date periods ended September 30, 2022 related to the revaluation of these liabilities. Nonrecurring Fair Value Measurements (Assets) — As of September 30, 2023, the Company had no major categories of assets estimated at fair value that were measured on a nonrecurring basis. The following table depicts the level in the fair value hierarchy of the inputs used to estimate fair value of assets measured on a nonrecurring basis as of December 31, 2022: Fair Value Measurements at Reporting Date Using Estimated Fair Value Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Loss (In thousands) As of December 31, 2022 Buildings 1 $ — $ — $ — $ — $ (810) 1 Reflects the non-cash impairment of building improvements (within the non-reportable segments). Nonrecurring Fair Value Measurements (Liabilities) — As of September 30, 2023 and December 31, 2022, the Company had no major categories of liabilities estimated at fair value that were measured on a nonrecurring basis. Gain on Sale of Revenue Equipment — Net gains on disposals, including disposals of property and equipment classified as assets held for sale, are reported in "Miscellaneous operating expenses" in the condensed consolidated statements of comprehensive income. The Company recorded net gains on disposals of: • $11.4 million and $15.6 million for the quarters ended September 30, 2023 and 2022, respectively. • $46.6 million and $73.4 million for the year-to-date periods ended September 30, 2023 and 2022, respectively. Fair Value of Pension Plan Assets — The following table sets forth by level the fair value hierarchy of ACT's pension plan financial assets accounted for at fair value on a recurring basis. Assets are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. ACT's assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of fair value assets and their placement within the fair value hierarchy levels. Fair Value Measurements at Reporting Date Using: Estimated Level 1 Inputs Level 2 Inputs Level 3 Inputs (In thousands) As of September 30, 2023 Fixed income funds 50,587 50,587 — — Cash and cash equivalents 387 387 — — Total pension plan assets $ 50,974 $ 50,974 $ — $ — As of December 31, 2022 US equity funds $ 10,901 $ 10,901 $ — $ — International equity funds 4,828 4,828 — — Fixed income funds 34,728 34,728 — — Cash and cash equivalents 2,078 2,078 — — Total pension plan assets $ 52,535 $ 52,535 $ — $ —

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2023
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Quarter Ended September 30, Year-to-Date September 30, 2023 2022 2023 2022 Provided by Knight-Swift Received by Knight-Swift Provided by Knight-Swift Received by Knight-Swift Provided by Knight-Swift Received by Knight-Swift Provided by Knight-Swift Received by Knight-Swift (In thousands) Facility and Equipment Leases $ — $ 21 $ — $ 78 $ — $ 67 $ — $ 263 Other Services $ — $ 9 $ 20 $ 9 $ 27 $ 402 $ 58 $ 27 September 30, 2023 December 31, 2022 Receivable Payable Receivable Payable (In thousands) Certain affiliates 1 $ — $ 40 $ 24 $ 39 1 "Certain affiliates" includes entities that are associated with various board members and executives and require approval by the Audit Committee of the Board prior to completing transactions. Transactions with these entities generally include facility and equipment leases, equipment sales, and other services. Aircraft Purchase — During the quarter ended September 30, 2023, the Company purchased an airplane for $6.0 million from related parties.

Information by Segment and Geog

Information by Segment and Geography	9 Months Ended
	Sep. 30, 2023
Segment Reporting [Abstract]
Information by Segment and Geography	Financial Information by Segment and Geography Segment Information Quarter Ended September 30, Year-to-Date September 30, 2023 2022 2023 2022 Revenue: (In thousands) Truckload $ 1,380,781 $ 1,160,735 $ 3,346,685 $ 3,430,075 LTL 284,168 278,615 806,577 817,587 Logistics 159,489 210,673 417,715 741,374 Intermodal 101,219 130,777 316,118 372,870 Subtotal $ 1,925,657 $ 1,780,800 $ 4,887,095 $ 5,361,906 Non-reportable segments 119,677 139,435 391,773 385,186 Intersegment eliminations (25,398) (23,396) (69,021) (62,133) Total revenue $ 2,019,936 $ 1,896,839 $ 5,209,847 $ 5,684,959 Quarter Ended September 30, Year-to-Date September 30, 2023 2022 2023 2022 Operating income (loss): (In thousands) Truckload $ 48,361 $ 175,802 $ 232,171 $ 587,215 LTL 32,275 30,859 89,095 101,003 Logistics 10,364 27,459 32,750 110,809 Intermodal (4,524) 12,834 (6,054) 42,176 Subtotal $ 86,476 $ 246,954 $ 347,962 $ 841,203 Non-reportable segments (5,420) 18,487 (28,089) 48,102 Operating income $ 81,056 $ 265,441 $ 319,873 $ 889,305 Quarter Ended September 30, Year-to-Date September 30, 2023 2022 2023 2022 Depreciation and amortization of property and equipment: (In thousands) Truckload $ 135,774 $ 114,946 $ 369,006 $ 338,014 LTL 17,069 15,699 50,077 46,280 Logistics 1,048 566 3,078 1,708 Intermodal 5,194 4,324 14,403 12,424 Subtotal $ 159,085 $ 135,535 $ 436,564 $ 398,426 Non-reportable segments 17,528 14,828 52,396 44,463 Depreciation and amortization of property and equipment $ 176,613 $ 150,363 $ 488,960 $ 442,889 Geographical Information In the aggregate, total revenue from the Company's international operations was less than 5.0% of consolidated total revenue for the quarter and year-to-date periods ended September 30, 2023 and 2022. Additionally, long-lived assets on the Company's international subsidiary balance sheets were less than 5.0% of consolidated total assets as of September 30, 2023 and December 31, 2022.

Introduction and Basis of Pre_2

Introduction and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	In management's opinion, these condensed consolidated financial statements were prepared in accordance with GAAP and include all adjustments necessary (consisting of normal recurring adjustments) for the fair statement of the periods presented.

Recently Issued Accounting Pr_2

Recently Issued Accounting Pronouncements (Tables)	9 Months Ended
	Sep. 30, 2023
Accounting Standards Update and Change in Accounting Principle [Abstract]
Recently Issued Accounting Pronouncements	Date Issued Reference Description Expected Adoption Date and Method Financial Statement Impact March 2023 ASU No. 2023-01: Leases (ASC 842), Common Control Arrangements The amendments in this ASU require that leasehold improvements associated with common control leases be amortized by the lessee over the useful life of the leasehold improvements and that leasehold improvements associated with common control leases be accounted for as a transfer between entities under common control through an adjustment to equity if the lessee no longer controls the use of the asset. January 2024, Prospective or retrospective Currently under evaluation, but not expected to be material July 2023 ASU No. 2023-03: Presentation of Financial Statements (ASC 205), Income Statement—Reporting Comprehensive Income (ASC 220), Distinguishing Liabilities from Equity (ASC 480), Equity (ASC 505), and Compensation—Stock Compensation (ASC 718) The amendments in this ASU reflect alignment to Staff Accounting Bulletin No. 120 ("SAB 120") that was issued by the SEC in November 2021. SAB 120 provides guidance to entities issuing share-based awards shortly before announcing material, nonpublic information. The guidance indicates that entities should consider such material nonpublic information to adjust the observable market if the effect of the release of the material nonpublic information is expected to affect the share price and the share-based awards are non-routine in nature. July 2023, prospective adoption Currently under evaluation, but not expected to be material August 2023 ASU No. 2023-05: Business Combinations — Joint Venture Formations (ASC 805-60), Recognition and Initial Measurement Requires a joint venture to initially measure all contributions received upon its formation at fair value. January 2025, prospective adoption Currently under evaluation, but not expected to be material October 2023 ASU No. 2023-06: Disclosure Improvements The amendments in this ASU updated several topics of the ASC to incorporate changes required by guidance made effective by SEC Final Rule No. 33-10532. The SEC Final Rule incorporates existing or incremental requirements of Regulation S-X into the accounting standards codification. October 2023, prospective adoption Presentation and disclosure impact only

Acquisitions (Tables)

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2023
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The purchase price allocation for U.S. Xpress is preliminary and has been allocated based on estimated fair values of the assets acquired and liabilities assumed at the acquisition date, and among other things may be pending the completion of the valuation of acquired tangible assets, an independent valuation of certain acquired intangible assets, assessment of lease agreements, assessment of certain liabilities, the calculation of deferred taxes based upon the underlying tax basis of assets acquired and liabilities assumed, and assessment of other tax related items as applicable. As the Company obtains more information, the preliminary purchase price allocation disclosed below is subject to change. Any future adjustments to the preliminary purchase price allocation, including changes within identifiable intangible assets or estimation uncertainty impacted by market conditions, may impact future net earnings. The purchase price allocation adjustments can be made through the end of the measurement period, which is not to exceed one year from the acquisition date. July 1, 2023 Opening Balance Sheet as Reported at September 30, 2023 Fair value of the consideration transferred $ 632,109 Cash and cash equivalents 3,321 Receivables 216,659 Prepaid expenses 21,347 Other current assets 47,317 Property and equipment 433,210 Operating lease right-of-use assets 337,055 Identifiable intangible assets 1 348,000 Other noncurrent assets 28,457 Total assets 1,435,366 Accounts payable (102,193) Accrued payroll and payroll-related expenses (27,485) Accrued liabilities (19,966) Claims accruals – current and noncurrent portions (180,251) Operating lease liabilities – current and noncurrent portions (376,763) Long-term debt and finance leases – current and noncurrent portions (337,949) Deferred tax liabilities (41,826) Other long-term liabilities (34,230) Total liabilities (1,120,663) Noncontrolling interest (391) Total stockholders' equity (391) Goodwill $ 317,797 1 Includes $184.5 million in customer relationships and $163.5 million in trade names.
Business Acquisition, Pro Forma Information	The following unaudited pro forma information combines the historical operations of the Company and U.S. Xpress giving effect to the U.S. Xpress Acquisition, and related transactions as if consummated on January 1, 2022, the beginning of the comparative period presented. Quarter Ended September 30, Year-to-Date September 30, 2023 2022 2023 2022 (In thousands, except per share data) Total revenue $ 2,019,936 $ 2,444,667 $ 6,165,131 $ 7,303,678 Net income attributable to Knight-Swift 33,584 100,112 146,522 599,058 Earnings per share – diluted 0.21 0.62 0.91 3.66

Accounts Receivable Securitiz_2

Accounts Receivable Securitization (Tables)	9 Months Ended
	Sep. 30, 2023
Transfers and Servicing [Abstract]
Schedule of Servicing Liabilities at Fair Value [Table Text Block]	The following table summarizes the key terms of the 2022 RSA (dollars in thousands): 2022 RSA (Dollars in thousands) Effective date October 3, 2022 Final maturity date October 1, 2025 Borrowing capacity $475,000 Accordion option 1 $100,000 Unused commitment fee rate 2 20 to 40 basis points Program fees on outstanding balances 3 one month SOFR + credit adjustment spread 10 basis points + 82.5 basis points 1 The accordion option increases the maximum borrowing capacity, subject to participation of the purchasers. 2 The 2022 RSA commitment fee rates are based on the percentage of the maximum borrowing capacity utilized. 3 As identified within the 2022 RSA, the lender can trigger an amendment by identifying and deciding upon a replacement for SOFR. Availability under the 2022 RSA is calculated as follows: September 30, 2023 December 31, 2022 (In thousands) Borrowing base, based on eligible receivables $ 363,800 $ 456,400 Less: outstanding borrowings 1 (362,000) (419,000) Availability under accounts receivable securitization facilities $ 1,800 $ 37,400 1 Outstanding borrowings are included in "Accounts receivable securitization" in the condensed consolidated balance sheets and are offset by deferred loan costs of $0.3 million and $0.4 million as of September 30, 2023 and December 31, 2022, respectively. Interest accrued on the aggregate principal balance at a rate of 6.3% and 5.1% as of September 30, 2023 and December 31, 2022, respectively.

Debt And Financing (Tables)

Debt And Financing (Tables)	9 Months Ended
	Sep. 30, 2023
Debt Disclosure [Abstract]
Schedule of Debt Balances by Instrument	Other than the Company's accounts receivable securitization as discussed in Note 5, the Company's long-term debt consisted of the following: September 30, 2023 December 31, 2022 (In thousands) 2021 Term Loan A-2, due September 3, 2024, net 1 2 199,865 199,755 2021 Term Loan A-3, due September 3, 2026, net 1 2 798,970 798,705 2023 Term Loan, due September 3, 2026, net 1 3 249,054 — Revenue equipment installment notes 1 4 296,884 — Prudential Notes, net 1 28,057 35,960 Other 9,322 3,042 Total long-term debt, including current portion 1,582,152 1,037,462 Less: current portion of long-term debt (320,441) (12,794) Long-term debt, less current portion $ 1,261,711 $ 1,024,668 September 30, 2023 December 31, 2022 (In thousands) Total long-term debt, including current portion $ 1,582,152 $ 1,037,462 2021 Revolver, due September 3, 2026 1 5 300,000 43,000 Long-term debt, including revolving line of credit $ 1,882,152 $ 1,080,462 1 Refer to Note 12 for information regarding the fair value of debt. 2 As of September 30, 2023, the carrying amounts of the 2021 Term Loan A-2 and 2021 Term Loan A-3 were net of $0.1 million and $1.0 million in deferred loan costs, respectively. As of December 31, 2022, the carrying amounts of the 2021 Term Loan A-2 and 2021 Term Loan A-3 were net of $0.2 million and $1.3 million in deferred loan costs, respectively. 3 As of September 30, 2023, the carrying amount of the 2023 Term Loan was net of $0.9 million in deferred loan costs. 4 The revenue equipment installment loans were assumed at the close of the U. S. Xpress Acquisition and have a weighted average interest rate of 4.5% as of September 30, 2023. 5 The Company also had outstanding letters of credit of $21.2 million and $15.8 million under the 2021 Revolver, primarily related to workers' compensation and self-insurance liabilities at September 30, 2023 and December 31, 2022, respectively. The Company also had outstanding letters of credit of $264.3 million and $173.1 million under a separate bilateral agreement which do not impact the availability of the 2021 Revolver as of September 30, 2023 and December 31, 2022, respectively.
Schedule of Long-term Debt Instruments	The following table presents the key terms of the 2021 Debt Agreement: 2021 Term Loan A-2 2021 Term Loan A-3 2021 Revolver 2 2021 Debt Agreement Terms (Dollars in thousands) Maximum borrowing capacity $200,000 $800,000 $1,100,000 Final maturity date September 3, 2024 September 3, 2026 September 3, 2026 Interest rate margin reference rate BSBY BSBY BSBY Interest rate minimum margin 1 0.75% 0.88% 0.88% Interest rate maximum margin 1 1.38% 1.50% 1.50% Minimum principal payment — amount $— $10,000 $— Minimum principal payment — frequency Once Quarterly Once Minimum principal payment — commencement date September 3, 2024 September 30, 2024 September 3, 2026 1 The interest rate margin for the 2021 Term Loans and 2021 Revolver is based on the Company's consolidated leverage ratio. As of September 30, 2023, interest accrued at 6.39% on the 2021 Term Loan A-2, 6.51% on the 2021 Term Loan A-3, and 6.53% on the 2021 Revolver. 2 The commitment fee for the unused portion of the 2021 Revolver is based on the Company's consolidated leverage ratio, and ranges from 0.1% to 0.2%. As of September 30, 2023, commitment fees on the unused portion of the 2021 Revolver accrued at 0.1% and outstanding letter of credit fees accrued at 1.1%.

Defined Benefit Pension Plan (T

Defined Benefit Pension Plan (Tables)	9 Months Ended
	Sep. 30, 2023
Retirement Benefits [Abstract]
Defined Benefit Plan, Assumptions	The following weighted-average assumptions were used to determine net periodic pension cost: Quarter Ended September 30, Year-to-Date September 30, 2023 2022 2023 2022 Discount rate 4.86 % 4.33 % 4.79 % 3.13 % Expected long-term rate of return on pension plan assets 6.00 % 6.00 % 6.00 % 6.00 %

Contingencies and Legal Proce_2

Contingencies and Legal Proceedings (Tables)	9 Months Ended
	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Schedule of Loss Contingencies by Contingency	EMPLOYEE COMPENSATION AND PAY PRACTICES MATTERS California Wage, Meal, and Rest Class Actions The plaintiffs generally allege one or more of the following: that the Company 1) failed to pay the California minimum wage; 2) failed to provide proper meal and rest periods; 3) failed to timely pay wages upon separation from employment; 4) failed to pay for all hours worked; 5) failed to pay overtime; 6) failed to properly reimburse work-related expenses; and 7) failed to provide accurate wage statements. Plaintiff(s) Defendant(s) Date instituted Court or agency currently pending in John Burnell 1 Swift Transportation Co., Inc March 22, 2010 United States District Court for the Central District of California James R. Rudsell 1 Swift Transportation Co. of Arizona, LLC and Swift Transportation Company April 5, 2012 United States District Court for the Central District of California Recent Developments and Current Status In April 2019, the parties reached settlement of this matter. In January 2020, the court granted final approval of the settlement. Two objectors appealed the court’s decision granting final approval of the settlement. The Company paid this settlement on July 10, 2023. California Wage and Hour Class Action Litigation - U.S. Xpress The plaintiffs generally allege one or more of the following: that class members were 1) not paid for off-the-clock work; 2) not provided duty free meal or rest breaks; 3) not paid premium pay in their absence; 4) not paid the California minimum wage for all hours worked in that state; 5) not provided accurate and complete itemized wage statements; and 6) not paid all accrued wages at the end of their employment. Plaintiff(s) Defendant(s) Date instituted Court or agency currently pending in Various U.S. Xpress December 23, 2015 United States District Court for the Central District of California Recent Developments and Current Status In February 2023, the parties reached an agreement to settle the California Wage and Hour Class Action Litigation, exclusive of employer-side taxes. On September 19, 2023, the court granted final approval of the settlement. No party objected to the settlement. The settlement amount (including employer-side taxes) is payable by November 2, 2023 and the loss has accordingly been accrued as of September 30, 2023. SHAREHOLDER MATTERS - U.S. Xpress Stockholder Derivative Action The plaintiffs generally allege that U.S. Xpress made false and/or misleading statements in the registration statement and prospectus filed with the SEC in connection with the IPO and that the Individual Defendants breached their fiduciary duties by causing or allowing U.S. Xpress to make such statements. The complaint alleges that U.S. Xpress has been damaged by the alleged wrongful conduct as a result of, among other things, being subjected to the time and expense of the securities class action lawsuits that have been filed relating to the IPO. In addition to a claim for alleged breach of fiduciary duties, the lawsuit alleges claims against the Individual Defendants for unjust enrichment, abuse of control, gross mismanagement, and waste of corporate assets. Plaintiff(s) Defendant(s) Date instituted Court or agency currently pending in Various Five executives and five independent board members of U.S. Xpress (collectively, the "Individual Defendants") June 7, 2019 District Court for Clark County, Nevada Recent Developments and Current Status The lawsuit was dismissed without prejudice on August 14, 2023. Stockholder Claims Between November 2018 and April 2019, eight substantially similar putative securities class action complaints were filed against U.S. Xpress and certain other defendants: five in the Circuit Court of Hamilton County, Tennessee (“Tennessee State Court Cases”), two in the U.S. District Court for the Eastern District of Tennessee (“Federal Court Cases”), and one in the Supreme Court of the State of New York (“New York State Court Case”). The putative class action lawsuits generally allege that U.S. Xpress made false and/or misleading statements in the registration statement and prospectus filed with the Securities and Exchange Commission (“SEC”) in connection with the June 2018 initial public offering (“IPO”). Plaintiff(s) Defendant(s) Date instituted Court or agency currently pending in Various U.S. Xpress, five officers or directors, and the seven underwriters who participated in the IPO November 2018 Circuit Court of Hamilton County, Tennessee, U.S. District Court for the Eastern District of Tennessee and Supreme Court of the State of New York SHAREHOLDER MATTERS - U.S. Xpress (Continued) Recent Developments and Current Status Tennessee State Court Cases The Consolidated Amended Class Action Complaint (the “Consolidated State Court Complaint”) filed on May 10, 2019 in the Circuit Court of Hamilton County, Tennessee against U.S. Xpress, five officers or directors, and the seven underwriters who participated in the IPO, alleges violations of Sections 11, 12(a)(2) and 15 of the Securities Act of 1933 (the “Securities Act”). The lawsuit is purportedly brought on behalf of a putative class. On November 13, 2020, the court presiding over the Tennessee State Court Cases entered an order, granting in part and denying in part the defendants’ Motions to Dismiss the Consolidated State Court Complaint. The court held that the plaintiffs failed to state a claim for violation of the Securities Act with respect to the majority of statements challenged as false or misleading in the Consolidated State Court Complaint. The court, however, held that the Consolidated State Court Complaint sufficiently alleged violations of the Securities Act with respect to one statement from the IPO registration statement and prospectus that the plaintiffs alleged to be false or misleading, both on theories of alleged misrepresentations and material omissions. New York State Court Case On March 14, 2019, a substantially similar putative class action complaint was filed in the Supreme Court of the State of New York, County of New York, by a different plaintiff alleging claims under Sections 11 and 15 of the Securities Act against the same defendants as in the Tennessee State Court Cases. On December 18, 2020, defendants filed a Motion to Dismiss or Stay the New York State Case both on the merits and in deference to the pending actions in Tennessee. On March 5, 2021, the court presiding over the New York State Case dismissed the case, and on January 13, 2022, the court entered a motion denying plaintiff’s motion for reconsideration. Federal Court Cases The operative amended complaint was filed on October 8, 2019 (“Amended Federal Complaint”), which named the same defendants as the Tennessee State Court Cases. The Amended Federal Complaint is made on behalf of a putative class. In addition to claims for alleged violations of Section 11 and 15 of the Securities Act, the Amended Federal Complaint alleges violations of Section 10(b) and 20(a) of the Securities Exchange Act of 1934 (“Exchange Act”) against U.S. Xpress, its Chief Executive Officer and its Chief Financial Officer. On June 30, 2020, the court presiding over the Federal Court Cases issued its ruling granting in part and denying in part the defendants’ Motions to Dismiss the Amended Federal Complaint. The court dismissed entirely the plaintiffs’ claims for alleged violations of the Exchange Act and further held that the plaintiffs failed to state a claim for violation of the Securities Act with respect to the majority of statements challenged as false or misleading in the Amended Federal Complaint. The court, however, held that the Federal Amended Complaint sufficiently alleged violations of the Securities Act with respect to two statements from the IPO registration statement and prospectus that the plaintiffs alleged to be false or misleading, both on theories of alleged misrepresentations and material omissions. Settlement The parties reached a settlement with the Federal Court and Tennessee State Court plaintiffs. On March 27, 2023, the parties filed the stipulation of settlement with the Federal Court, and on March 28, 2023, the Federal Court entered an order granting preliminary approval of the settlement. The Federal Court entered an order granting final approval of the settlement on July 12, 2023. The monetary component of the settlement in principle is to be paid by the applicable insurance carriers. 1 Individually and on behalf of all others similarly situated.

Share Repurchase Plans (Tables)

Share Repurchase Plans (Tables)	9 Months Ended
	Sep. 30, 2023
Equity [Abstract]
Schedule of Share Repurchases	The following table presents the Company's repurchases of its common stock during 2022 under the respective share repurchase plans, excluding advisory fees: Share Repurchase Plan Quarter Ended September 30, 2022 Year-to-Date September 30, 2022 Board Approval Date Authorized Amount Shares Amount Shares Amount (shares and dollars in thousands) November 24, 2020 $250,000 — $ — 2,821 $ 149,982 April 19, 2022 1 $350,000 — $ — 3,180 $ 149,959 — $ — 6,001 $ 299,941 1 $200.0 million remained available under the 2022 Knight-Swift Repurchase Plan as of September 30, 2023 and December 31, 2022.

Weighted Average Shares Outst_2

Weighted Average Shares Outstanding (Tables)	9 Months Ended
	Sep. 30, 2023
Earnings Per Share [Abstract]
Calculation Of Basic And Diluted Earnings Per Share Attributable To Stockholders	The following table reconciles basic weighted average shares outstanding to diluted weighted average shares outstanding: Quarter Ended September 30, Year-to-Date September 30, 2023 2022 2023 2022 (In thousands) Basic weighted average common shares outstanding 161,332 160,665 161,124 162,785 Dilutive effect of equity awards 556 907 658 935 Diluted weighted average common shares outstanding 161,888 161,572 161,782 163,720 Anti-dilutive shares excluded from earnings per diluted share 1 57 132 141 321 1 Shares were excluded from the dilutive-effect calculation because the outstanding awards' exercise prices were greater than the average market price of the Company's common stock for the periods presented.

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Fair Value by Balance Sheet Grouping	The following table presents the carrying amounts and estimated fair values of the Company's major categories of financial assets and liabilities: September 30, 2023 December 31, 2022 Condensed Consolidated Balance Sheets Caption Carrying Estimated Carrying Estimated (In thousands) Financial Assets: Equity method investments Other long-term assets $ 97,878 $ 97,878 $ 103,517 $ 103,517 Investments in equity securities Other long-term assets — — 1,668 1,668 Convertible note Other current assets — — 11,341 11,341 Financial Liabilities: 2021 Term Loan A-2, due September 2024 1 Finance lease liabilities and long-term debt – current portion 199,865 200,000 199,755 200,000 2021 Term Loan A-3, due September 2026 1 Finance lease liabilities and long-term debt 798,970 800,000 798,705 800,000 2023 Term Loan, due September 2026 2 Long-term debt – less current portion 249,054 250,000 — — 2021 Revolver, due September 2026 Revolving line of credit 300,000 300,000 43,000 43,000 Revenue equipment installment notes 3 Finance lease liabilities and long-term debt 296,884 296,884 — — 2021 Prudential Notes 4 Finance lease liabilities and long-term debt 28,057 28,085 35,960 36,014 2022 RSA, due October 2025 5 Accounts receivable securitization 361,681 362,000 418,561 419,000 Mandatorily redeemable contingent consideration 6 Accrued liabilities 134,107 134,107 — — Contingent consideration 6 Accrued liabilities, Other long-term liabilities 40,859 40,859 4,217 4,217 1 As of September 30, 2023, the carrying amounts of the 2021 Term Loan A-2 and 2021 Term Loan A-3 were net of $0.1 million and $1.0 million in deferred loan costs, respectively. As of December 31, 2022, the carrying amounts of the 2021 Term Loan A-2 and 2021 Term Loan A-3 were net of $0.2 million and $1.3 million in deferred loan costs, respectively. 2 As of September 30, 2023, the carrying amount of the 2023 Term Loan was net of $0.9 million in deferred loan costs. 3 As of September 30, 2023, the carrying amount of the revenue equipment installment notes included $1.6 million in fair value adjustments. 4 As of September 30, 2023, the carrying amount of the 2021 Prudential Notes was net of approximately $28,000 i n deferred loan costs and included $1.3 million in fair value adjustments. As of December 31, 2022, the carrying amount of the 2021 Prudential Notes was net of $0.1 million in deferred loan costs and included $1.7 million in fair value adjustments. 5 The carrying amount of the 2022 RSA was net of $0.3 million and $0.4 million in deferred loan costs as of September 30, 2023 and December 31, 2022, respectively. 6 Refer to Note 3 for information regarding the contingent consideration related to the U.S. Xpress Acquisition.
Recurring Fair Value Measurements (Assets)	The following table depicts the level in the fair value hierarchy of the inputs used to estimate the fair value of assets measured on a recurring basis as of December 31, 2022: Fair Value Measurements at Reporting Date Using Estimated Fair Value Level 1 Inputs Level 2 Inputs Level 3 Inputs Unrealized Gain (Loss) Position (In thousands) As of December 31, 2022 Convertible notes 1 $ 11,341 $ — $ — $ 11,341 $ 1,341 Investments in equity securities 2 1,668 1,668 — — (50,918) 1 Convertible notes — The condensed consolidated statements of comprehensive income include the fair value activities from the Company's convertible notes within "Other income (expenses), net". The estimated fair value is based on probability-weighted discounted cash flow analysis of the corresponding pay-off/redemption. • Quarter Ended Gain (Loss) Activities: The Company recognized an unrealized gain of $0.3 million during the quarter ended September 30, 2022. • Year-to-date Gain (Loss) Activities: The Company recognized an unrealized gain of $0.9 million during the year-to-date period ended September 30, 2022. 2 Investments in equity securities — The condensed consolidated statements of comprehensive income include the fair value activities from the Company's investments in equity securities within "Other income (expenses), net". The estimated fair value is based on quoted prices in active markets that are readily and regularly obtainable. • Quarter Ended Gain (Loss) Activities: During the quarter ended September 30, 2022, the Company recognized a gain of $0.5 million, which consisted of $7.0 million in realized gains from the Company's other investments in equity securities. This was partially offset by $6.5 million in unrealized losses, primarily from mark-to-market adjustments of the Company's equity investment in Embark. • Year-to-date Gain (Loss) Activities: During the year-to-date period ended September 30, 2022, the Company recognized a loss of $51.0 million, which consisted of $62.4 million in unrealized losses, primarily from mark-to-market adjustments of the Company's investment in Embark. This was partially offset by $11.4 million realized gains from the Company's other investments in equity securities. Fair Value Measurements at Reporting Date Using: Estimated Level 1 Inputs Level 2 Inputs Level 3 Inputs (In thousands) As of September 30, 2023 Fixed income funds 50,587 50,587 — — Cash and cash equivalents 387 387 — — Total pension plan assets $ 50,974 $ 50,974 $ — $ — As of December 31, 2022 US equity funds $ 10,901 $ 10,901 $ — $ — International equity funds 4,828 4,828 — — Fixed income funds 34,728 34,728 — — Cash and cash equivalents 2,078 2,078 — — Total pension plan assets $ 52,535 $ 52,535 $ — $ —
Recurring Fair Value Measurements (Liabilities)	The following table depicts the level in the fair value hierarchy of the inputs used to estimate the fair value of liabilities measured on a recurring basis as of September 30, 2023 and December 31, 2022: Fair Value Measurements at Reporting Date Using Estimated Fair Value Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Gain (Loss) (In thousands) As of September 30, 2023 Mandatorily redeemable contingent consideration 1 $ 134,107 $ — $ — $ 134,107 $ — Contingent consideration 1 2 $ 40,859 $ — $ — $ 40,859 $ 3,359 As of December 31, 2022 Contingent consideration 2 $ 4,217 $ — $ — $ 4,217 $ — 1 Refer to Note 3 for information regarding the contingent consideration related to the U.S. Xpress Acquisition. 2 Contingent consideration is associated with acquisitions and investments. The Company recognized a gain of $0.9 million during the quarter ended September 30, 2023 and a gain of $3.4 million during the year-to-date period ended September 30, 2023. The Company did not recognize any gains (losses) in the quarter and year-to-date periods ended September 30, 2022 related to the revaluation of these liabilities.
Nonrecurring Fair Value Measurements (Assets)	The following table depicts the level in the fair value hierarchy of the inputs used to estimate fair value of assets measured on a nonrecurring basis as of December 31, 2022: Fair Value Measurements at Reporting Date Using Estimated Fair Value Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Loss (In thousands) As of December 31, 2022 Buildings 1 $ — $ — $ — $ — $ (810) 1 Reflects the non-cash impairment of building improvements (within the non-reportable segments).

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2023
Related Party Transactions [Abstract]
Related Party Transactions	Quarter Ended September 30, Year-to-Date September 30, 2023 2022 2023 2022 Provided by Knight-Swift Received by Knight-Swift Provided by Knight-Swift Received by Knight-Swift Provided by Knight-Swift Received by Knight-Swift Provided by Knight-Swift Received by Knight-Swift (In thousands) Facility and Equipment Leases $ — $ 21 $ — $ 78 $ — $ 67 $ — $ 263 Other Services $ — $ 9 $ 20 $ 9 $ 27 $ 402 $ 58 $ 27 September 30, 2023 December 31, 2022 Receivable Payable Receivable Payable (In thousands) Certain affiliates 1 $ — $ 40 $ 24 $ 39 1 "Certain affiliates" includes entities that are associated with various board members and executives and require approval by the Audit Committee of the Board prior to completing transactions. Transactions with these entities generally include facility and equipment leases, equipment sales, and other services.

Information by Segment and Ge_2

Information by Segment and Geography (Tables)	9 Months Ended
	Sep. 30, 2023
Segment Reporting [Abstract]
Summary Of Financial Information By Segments	Quarter Ended September 30, Year-to-Date September 30, 2023 2022 2023 2022 Revenue: (In thousands) Truckload $ 1,380,781 $ 1,160,735 $ 3,346,685 $ 3,430,075 LTL 284,168 278,615 806,577 817,587 Logistics 159,489 210,673 417,715 741,374 Intermodal 101,219 130,777 316,118 372,870 Subtotal $ 1,925,657 $ 1,780,800 $ 4,887,095 $ 5,361,906 Non-reportable segments 119,677 139,435 391,773 385,186 Intersegment eliminations (25,398) (23,396) (69,021) (62,133) Total revenue $ 2,019,936 $ 1,896,839 $ 5,209,847 $ 5,684,959 Quarter Ended September 30, Year-to-Date September 30, 2023 2022 2023 2022 Operating income (loss): (In thousands) Truckload $ 48,361 $ 175,802 $ 232,171 $ 587,215 LTL 32,275 30,859 89,095 101,003 Logistics 10,364 27,459 32,750 110,809 Intermodal (4,524) 12,834 (6,054) 42,176 Subtotal $ 86,476 $ 246,954 $ 347,962 $ 841,203 Non-reportable segments (5,420) 18,487 (28,089) 48,102 Operating income $ 81,056 $ 265,441 $ 319,873 $ 889,305 Quarter Ended September 30, Year-to-Date September 30, 2023 2022 2023 2022 Depreciation and amortization of property and equipment: (In thousands) Truckload $ 135,774 $ 114,946 $ 369,006 $ 338,014 LTL 17,069 15,699 50,077 46,280 Logistics 1,048 566 3,078 1,708 Intermodal 5,194 4,324 14,403 12,424 Subtotal $ 159,085 $ 135,535 $ 436,564 $ 398,426 Non-reportable segments 17,528 14,828 52,396 44,463 Depreciation and amortization of property and equipment $ 176,613 $ 150,363 $ 488,960 $ 442,889

Introduction and Basis of Pre_3

Introduction and Basis of Presentation (Details)	9 Months Ended
	Sep. 30, 2023 Vehicle Segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operational tractors in fleet	20,054
Number of company tractors	17,977
Number of independent contractor tractors	2,077
Number of trailers	85,125
Number of LTL tractors	3,177
Number of LTL trailers	8,445
Number of intermodal tractors	647
Number of intermodal containers	12,780
Number of reportable segments | Segment	4

Recently Issued Accounting Pr_3

Recently Issued Accounting Pronouncements (Details)	9 Months Ended
	Sep. 30, 2023
Accounting Standards Update 2023-01
Recently Issued Accounting Pronouncements [Line Items]
New Accounting Pronouncement or change in Accounting Principle, Description	The amendments in this ASU require that leasehold improvements associated with common control leases be amortized by the lessee over the useful life of the leasehold improvements and that leasehold improvements associated with common control leases be accounted for as a transfer between entities under common control through an adjustment to equity if the lessee no longer controls the use of the asset.
New Accounting Pronouncement Adoption Method and Date	January 2024, Prospective or retrospective
New Accounting Pronouncement Financial Statement Impact	Currently under evaluation, but not expected to be material
Accounting Standards Update 2023-03
Recently Issued Accounting Pronouncements [Line Items]
New Accounting Pronouncement or change in Accounting Principle, Description	The amendments in this ASU reflect alignment to Staff Accounting Bulletin No. 120 ("SAB 120") that was issued by the SEC in November 2021. SAB 120 provides guidance to entities issuing share-based awards shortly before announcing material, nonpublic information. The guidance indicates that entities should consider such material nonpublic information to adjust the observable market if the effect of the release of the material nonpublic information is expected to affect the share price and the share-based awards are non-routine in nature.
New Accounting Pronouncement Adoption Method and Date	July 2023, prospective adoption
New Accounting Pronouncement Financial Statement Impact	Currently under evaluation, but not expected to be material
Accounting Standards Update 2023-05
Recently Issued Accounting Pronouncements [Line Items]
New Accounting Pronouncement or change in Accounting Principle, Description	Requires a joint venture to initially measure all contributions received upon its formation at fair value.
New Accounting Pronouncement Adoption Method and Date	January 2025, prospective adoption
New Accounting Pronouncement Financial Statement Impact	Currently under evaluation, but not expected to be material
Accounting Standards Update 2023-06
Recently Issued Accounting Pronouncements [Line Items]
New Accounting Pronouncement or change in Accounting Principle, Description	The amendments in this ASU updated several topics of the ASC to incorporate changes required by guidance made effective by SEC Final Rule No. 33-10532. The SEC Final Rule incorporates existing or incremental requirements of Regulation S-X into the accounting standards codification.
New Accounting Pronouncement Adoption Method and Date	October 2023, prospective adoption
New Accounting Pronouncement Financial Statement Impact	Presentation and disclosure impact only

Acquisitions - Narrative (Detai

Acquisitions - Narrative (Details) - USD ($) $ in Thousands					3 Months Ended			9 Months Ended
		Sep. 30, 2023		Jul. 01, 2023	Sep. 30, 2023		Sep. 30, 2022	Sep. 30, 2023		Sep. 30, 2022	Dec. 31, 2022
Business Acquisition [Line Items]
U.S. Xpress assumed equity awards				$ 1,500	$ 1,462			$ 1,462		$ 0
Business Combination, Contingent Consideration, Liability	[1]	$ 40,859			40,859			40,859			$ 4,217
Total revenue					2,019,936		$ 1,896,839	5,209,847		5,684,959
Net income					59,897		194,792	226,514		622,522
Amortization of Intangible Assets					18,907		$ 16,254	51,595		$ 48,635
U.S. Xpress
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition				Jul. 01, 2023
Business Combination, Consideration Transferred Excluding Owned Shares and Noncontrolling Interests				$ 630,000
Fair value of the consideration transferred		632,109
Total revenue					461,600			461,600
Net income					19,900			19,900
Amortization of Intangible Assets					2,300			2,300
Business Combination, Acquisition Related Costs					6,500			31,800
U.S. Xpress | Consideration for Debt Payments
Business Acquisition [Line Items]
Fair value of the consideration transferred				139,800
U.S. Xpress | Contingent consideration (total payment)
Business Acquisition [Line Items]
Business Combination, Contingent Consideration, Liability				174,100
U.S. Xpress | Class B
Business Acquisition [Line Items]
Business Combination, Contingent Consideration, Liability				40,000
Class B Exercise Price				40,000
Target Operating Income				250,000
U.S. Xpress | Class A
Business Acquisition [Line Items]
Business Combination, Contingent Consideration, Liability		$ 134,107	[1]	134,100	$ 134,107	[1]		$ 134,107	[1]		$ 0	[1]
Class A Exercise Price				140,000
Target Operating Income				175,000
U.S. Xpress | Cash paid for acquisition
Business Acquisition [Line Items]
Fair value of the consideration transferred				$ 454,400
[1]Refer to Note 3 for information regarding the contingent consideration related to the U.S. Xpress Acquisition

Acquisitions - Tables (Details)

Acquisitions - Tables (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Business Acquisition [Line Items]
Noncontrolling interest			$ (5,839)		$ (7,555)
Goodwill		$ 3,844,252	3,844,252		3,844,252		$ 3,519,339
U.S. Xpress
Business Acquisition [Line Items]
Fair value of the consideration transferred		632,109
Cash and cash equivalents		3,321	3,321		3,321
Receivables		216,659	216,659		216,659
Prepaid expenses		21,347	21,347		21,347
Other current assets		47,317	47,317		47,317
Property and equipment		433,210	433,210		433,210
Operating lease right-of-use assets		337,055	337,055		337,055
Identifiable intangible assets 1	[1]	348,000	348,000		348,000
Other noncurrent assets		28,457	28,457		28,457
Total assets		1,435,366	1,435,366		1,435,366
Accounts payable		(102,193)	(102,193)		(102,193)
Accrued payroll and payroll-related expenses		(27,485)	(27,485)		(27,485)
Accrued liabilities		(19,966)	(19,966)		(19,966)
Claims accruals – current and noncurrent portions		(180,251)	(180,251)		(180,251)
Operating lease liabilities – current and noncurrent portions		(376,763)	(376,763)		(376,763)
Long-term debt and finance leases – current and noncurrent portions		(337,949)	(337,949)		(337,949)
Deferred Tax Liabilities		(41,826)	(41,826)		(41,826)
Other long-term liabilities		(34,230)	(34,230)		(34,230)
Total liabilities		(1,120,663)	(1,120,663)		(1,120,663)
Noncontrolling interest		(391)
Total stockholders' equity		(391)	(391)		(391)
Goodwill		317,797	317,797		317,797
Trade names		163,500	163,500		163,500
Total revenue			2,019,936	$ 2,444,667	6,165,131	$ 7,303,678
Net income attributable to Knight-Swift			$ 33,584	$ 100,112	$ 146,522	$ 599,058
Earnings per share – diluted			$ 0.21	$ 0.62	$ 0.91	$ 3.66
U.S. Xpress | Customer relationships [Member]
Business Acquisition [Line Items]
Finite-lived intangible assets		$ 184,500	$ 184,500		$ 184,500
[1]Includes $184.5 million in customer relationships and $163.5 million in trade names.

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Jul. 01, 2023	Dec. 31, 2022
Income Tax Contingency [Line Items]
Effective tax rate	(2.10%)	25.20%	19.10%	24.90%
Deferred Tax Assets, Valuation Allowance	$ 10.4		$ 10.4
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	14.6
Accrued interest and penalties	$ 0		$ 0			$ 0.2
Year subject to examination	2017
U.S. Xpress
Income Tax Contingency [Line Items]
Deferred Tax Assets, Valuation Allowance					$ 25
State and Local Jurisdiction [Member] | Minimum [Member]
Income Tax Contingency [Line Items]
Year under income tax examination			2009
State and Local Jurisdiction [Member] | Maximum [Member]
Income Tax Contingency [Line Items]
Year under income tax examination			2021

Accounts Receivable Securitiz_3

Accounts Receivable Securitization (Details) - USD ($) $ in Thousands		Oct. 23, 2023	Sep. 30, 2023	Dec. 31, 2022	Oct. 03, 2022
2022 RSA
Servicing Liabilities at Fair Value [Line Items]
Effective date					Oct. 03, 2022
Final maturity date					Oct. 01, 2025
Receivables Sales Agreement, Borrowing Capacity					$ 475,000
Accordion Option Accounts Receivable Securitization	[1]				$ 100,000
Unused commitment fee rate	[2]				20 to 40 basis points
Program fees on outstanding balances	[3]				one month SOFR + credit adjustment spread 10 basis points + 82.5 basis points
Borrowing base, based on eligible receivables			$ 363,800	$ 456,400
Accounts receivable securitization	[4]		(362,000)	(419,000)
Availability under accounts receivable securitization facilities			1,800	37,400
Deferred loan costs			$ 300	$ 400
Debt Instrument, Interest Rate During Period			6.30%	5.10%
2023 RSA | Subsequent Event [Member]
Servicing Liabilities at Fair Value [Line Items]
Effective date		Oct. 23, 2023
Receivables Sales Agreement, Borrowing Capacity		$ 575,000
[1]The accordion option increases the maximum borrowing capacity, subject to participation of the purchasers.[2]The 2022 RSA commitment fee rates are based on the percentage of the maximum borrowing capacity utilized.[3]As identified within the 2022 RSA, the lender can trigger an amendment by identifying and deciding upon a replacement for SOFR.[4] Outstanding borrowings are included in "Accounts receivable securitization" in the condensed consolidated balance sheets and are offset by deferred loan costs of $0.3 million and $0.4 million as of September 30, 2023 and December 31, 2022, respectively. Interest accrued on the aggregate principal balance at a rate of 6.3% and 5.1% as of September 30, 2023 and December 31, 2022, respectively.

Debt And Financing (Details)

Debt And Financing (Details) - USD ($) $ in Thousands		Sep. 30, 2023	Jul. 01, 2023	Jun. 22, 2023	Sep. 03, 2021	Dec. 31, 2022	Sep. 30, 2022
Debt Instrument [Line Items]
Long-Term Debt		$ 1,582,152				$ 1,037,462
Secured Debt	[1],[2]	296,884				0
Less: current portion of long-term debt		(320,441)				(12,794)
Long-term debt – less current portion		1,261,711				1,024,668
Revolving line of credit		300,000				43,000
Long-term Debt		1,882,152				1,080,462
Letters of Credit Outstanding, Amount		264,300				173,100
Debt Instrument, Collateral Amount		256,700
2021 Term Loan A-2
Debt Instrument [Line Items]
Long-Term Debt	[1],[3]	199,865				199,755
Deferred loan costs		$ 100				200
Line of Credit Facility, Maximum Borrowing Capacity					$ 200,000
Final maturity date					Sep. 03, 2024
Program fees on outstanding balances					BSBY
Minimum principal payment — amount					$ 0
Minimum principal payment — frequency					Once
Minimum principal payment — commencement date					Sep. 03, 2024
Debt Instrument, Interest Rate During Period		6.39%
2021 Term Loan A-2 | Minimum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	[4]				0.75%
2021 Term Loan A-2 | Maximum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	[4]				1.38%
2021 Term Loan A-3
Debt Instrument [Line Items]
Long-Term Debt	[1],[3]	$ 798,970				798,705
Deferred loan costs		$ 1,000				1,300
Line of Credit Facility, Maximum Borrowing Capacity					$ 800,000
Final maturity date					Sep. 03, 2026
Program fees on outstanding balances					BSBY
Minimum principal payment — amount					$ 10,000
Minimum principal payment — frequency					Quarterly
Minimum principal payment — commencement date					Sep. 30, 2024
Debt Instrument, Interest Rate During Period		6.51%
2021 Term Loan A-3 | Minimum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	[4]				0.88%
2021 Term Loan A-3 | Maximum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	[4]				1.50%
2023 Term Loan
Debt Instrument [Line Items]
Long-Term Debt	[1],[5]	$ 249,054				0
Deferred loan costs							$ 900
Line of Credit Facility, Maximum Borrowing Capacity				$ 250,000
Final maturity date				Sep. 03, 2026
Program fees on outstanding balances				SOFR
Debt Instrument, Interest Rate, Stated Percentage				1.375%
Minimum principal payment — amount				$ 0
Debt Instrument, Interest Rate During Period		6.79%
Debt Instrument, Basis Spread on Variable Rate				0.10%
2021 Prudential Notes
Debt Instrument [Line Items]
Long-Term Debt	[1]	$ 28,057				35,960
Debt Instrument, Unused Borrowing Capacity, Amount		98,200
2021 Prudential Notes | Minimum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage					4.05%
2021 Prudential Notes | Maximum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage					4.40%
Other Debt
Debt Instrument [Line Items]
Secured Debt, Other		9,322				3,042
2021 Revolver
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		$ 21,200				15,800
Line of Credit Facility, Maximum Borrowing Capacity	[6]				$ 1,100,000
Final maturity date	[6]				Sep. 03, 2026
Program fees on outstanding balances	[6]				BSBY
Minimum principal payment — amount	[6]				$ 0
Minimum principal payment — frequency	[6]				Once
Minimum principal payment — commencement date	[6]				Sep. 03, 2026
Debt Instrument, Interest Rate During Period		6.53%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage		0.10%
Line of Credit Facility, Commitment Fee Percentage		1.10%
2021 Revolver | Minimum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	[4],[6]				0.88%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage					0.10%
2021 Revolver | Maximum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	[4],[6]				1.50%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage					0.20%
U.S. Xpress Revenue Equipment Installment Notes
Debt Instrument [Line Items]
Debt, Weighted Average Interest Rate		4.50%
Final maturity date			Mar. 15, 2028
U.S. Xpress Revenue Equipment Installment Notes | Minimum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage					2%
Debt Instrument, Term		36 months
U.S. Xpress Revenue Equipment Installment Notes | Maximum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage					7%
Debt Instrument, Term		84 months
Line of Credit | 2021 Revolver
Debt Instrument [Line Items]
Revolving line of credit	[1],[7]	$ 300,000				43,000
Loans Payable [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity					$ 2,300,000
Loans Payable [Member] | 2021 Term Loan A-2
Debt Instrument [Line Items]
Deferred loan costs		100				200
Loans Payable [Member] | 2021 Term Loan A-3
Debt Instrument [Line Items]
Deferred loan costs		1,000				$ 1,300
Loans Payable [Member] | 2023 Term Loan
Debt Instrument [Line Items]
Deferred loan costs		$ 900
Loans Payable [Member] | 2021 Prudential Notes
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity					$ 125,000
[1]Refer to Note 12 for information regarding the fair value of debt.[2]The revenue equipment installment loans were assumed at the close of the U. S. Xpress Acquisition and have a weighted average interest rate of 4.5% as of September 30, 2023.[3]As of September 30, 2023, the carrying amounts of the 2021 Term Loan A-2 and 2021 Term Loan A-3 were net of $0.1 million and $1.0 million in deferred loan costs, respectively. As of December 31, 2022, the carrying amounts of the 2021 Term Loan A-2 and 2021 Term Loan A-3 were net of $0.2 million and $1.3 million in deferred loan costs, respectively.[4]The interest rate margin for the 2021 Term Loans and 2021 Revolver is based on the Company's consolidated leverage ratio. As of September 30, 2023, interest accrued at 6.39% on the 2021 Term Loan A-2, 6.51% on the 2021 Term Loan A-3, and 6.53% on the 2021 Revolver.[5]As of September 30, 2023, the carrying amount of the 2023 Term Loan was net of $0.9 million in deferred loan costs.[6]The commitment fee for the unused portion of the 2021 Revolver is based on the Company's consolidated leverage ratio, and ranges from 0.1% to 0.2%. As of September 30, 2023, commitment fees on the unused portion of the 2021 Revolver accrued at 0.1% and outstanding letter of credit fees accrued at 1.1%.[7]The Company also had outstanding letters of credit of $21.2 million and $15.8 million under the 2021 Revolver, primarily related to workers' compensation and self-insurance liabilities at September 30, 2023 and December 31, 2022, respectively. The Company also had outstanding letters of credit of $264.3 million and $173.1 million under a separate bilateral agreement which do not impact the availability of the 2021 Revolver as of September 30, 2023 and December 31, 2022, respectively.

Defined Benefit Pension Plan (D

Defined Benefit Pension Plan (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Retirement Benefits [Abstract]
Discount Rate (Point in Time)	5.58%		5.58%
Discount Rate (Period of Time)	4.86%	4.33%	4.79%	3.13%
Expected long-term rate of return on pension plan assets	6%	6%	6%	6%

Purchase Commitments (Details)

Purchase Commitments (Details) $ in Millions	Sep. 30, 2023 USD ($)
Capital Addition Purchase Commitments Total Revenue Equipment [Member]
Long-term Purchase Commitment [Line Items]
Purchase Obligation, to be Paid, Year One	$ 284.2
Purchase Obligation, to be Paid, Year Two	0
Purchase Obligation, to be Paid, Year Three	0
Purchase Obligation, Due in Fourth and Fifth Year	0
Purchase Obligation, Due after Fifth Year	0
Capital Addition Purchase Commitments of Tractors [Member]
Long-term Purchase Commitment [Line Items]
Purchase Obligation, to be Paid, Year One	179.7
Capital Addition Purchase Commitments Non revenue equipment [Member]
Long-term Purchase Commitment [Line Items]
Purchase Obligation, Future Minimum Payments, Remainder of Fiscal Year	49.8
Purchase Obligation, Due in Second and Third Year	19.1
Purchase Obligation, Due in Fourth and Fifth Year	2
Purchase Obligation, Due after Fifth Year	$ 0

Contingencies and Legal Proce_3

Contingencies and Legal Proceedings (Details) $ in Millions	9 Months Ended
	Sep. 30, 2023 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Loss contingency accrual	$ 9.2
Employee Compensation and Pay Practices Matters [Member] | California Wage, Meal, and Rest Class Action [Member]
Loss Contingencies [Line Items]
Loss contingency, allegations	The plaintiffs generally allege one or more of the following: that the Company 1) failed to pay the California minimum wage; 2) failed to provide proper meal and rest periods; 3) failed to timely pay wages upon separation from employment; 4) failed to pay for all hours worked; 5) failed to pay overtime; 6) failed to properly reimburse work-related expenses; and 7) failed to provide accurate wage statements.
Loss contingency, opinion of counsel	In April 2019, the parties reached settlement of this matter. In January 2020, the court granted final approval of the settlement. Two objectors appealed the court’s decision granting final approval of the settlement. The Company paid this settlement on July 10, 2023.
Employee Compensation and Pay Practices Matters [Member] | California Wage, Meal, and Rest Class Action [Member] | California Wage, Meal, and Rest Class Action 1 [Member]
Loss Contingencies [Line Items]
Loss contingency, name of plaintiffs	John Burnell 1	[1]
Loss contingency, name of defendant	Swift Transportation Co., Inc
Lawsuit filing date	March 22, 2010
Loss contingency, domicile of litigation	United States District Court for the Central District of California
Employee Compensation and Pay Practices Matters [Member] | California Wage, Meal, and Rest Class Action [Member] | California Wage, Meal, and Rest Class Action 2 [Member]
Loss Contingencies [Line Items]
Loss contingency, name of plaintiffs	James R. Rudsell 1	[1]
Loss contingency, name of defendant	Swift Transportation Co. of Arizona, LLC and Swift Transportation Company
Lawsuit filing date	April 5, 2012
Loss contingency, domicile of litigation	United States District Court for the Central District of California
Employee Compensation and Pay Practices Matters [Member] | California Wage and Hour Class Action
Loss Contingencies [Line Items]
Loss contingency, allegations	The plaintiffs generally allege one or more of the following: that class members were 1) not paid for off-the-clock work; 2) not provided duty free meal or rest breaks; 3) not paid premium pay in their absence; 4) not paid the California minimum wage for all hours worked in that state; 5) not provided accurate and complete itemized wage statements; and 6) not paid all accrued wages at the end of their employment.
Loss contingency, name of plaintiffs	Various
Loss contingency, name of defendant	U.S. Xpress
Lawsuit filing date	December 23, 2015
Loss contingency, domicile of litigation	United States District Court for the Central District of California
Loss contingency, opinion of counsel	In February 2023, the parties reached an agreement to settle the California Wage and Hour Class Action Litigation, exclusive of employer-side taxes. On September 19, 2023, the court granted final approval of the settlement. No party objected to the settlement. The settlement amount (including employer-side taxes) is payable by November 2, 2023 and the loss has accordingly been accrued as of September 30, 2023.
Regulatory Matters | Stockholder Derivative Matter
Loss Contingencies [Line Items]
Loss contingency, allegations	The plaintiffs generally allege that U.S. Xpress made false and/or misleading statements in the registration statement and prospectus filed with the SEC in connection with the IPO and that the Individual Defendants breached their fiduciary duties by causing or allowing U.S. Xpress to make such statements. The complaint alleges that U.S. Xpress has been damaged by the alleged wrongful conduct as a result of, among other things, being subjected to the time and expense of the securities class action lawsuits that have been filed relating to the IPO. In addition to a claim for alleged breach of fiduciary duties, the lawsuit alleges claims against the Individual Defendants for unjust enrichment, abuse of control, gross mismanagement, and waste of corporate assets.
Loss contingency, name of plaintiffs	Various
Loss contingency, name of defendant	Five executives and five independent board members of U.S. Xpress (collectively, the "Individual Defendants")
Lawsuit filing date	June 7, 2019
Loss contingency, domicile of litigation	District Court for Clark County, Nevada
Loss contingency, opinion of counsel	The lawsuit was dismissed without prejudice on August 14, 2023.
Regulatory Matters | Stockholder Claims
Loss Contingencies [Line Items]
Loss contingency, allegations	Between November 2018 and April 2019, eight substantially similar putative securities class action complaints were filed against U.S. Xpress and certain other defendants: five in the Circuit Court of Hamilton County, Tennessee (“Tennessee State Court Cases”), two in the U.S. District Court for the Eastern District of Tennessee (“Federal Court Cases”), and one in the Supreme Court of the State of New York (“New York State Court Case”). The putative class action lawsuits generally allege that U.S. Xpress made false and/or misleading statements in the registration statement and prospectus filed with the Securities and Exchange Commission (“SEC”) in connection with the June 2018 initial public offering (“IPO”).
Loss contingency, name of plaintiffs	Various
Loss contingency, name of defendant	U.S. Xpress, five officers or directors, and the seven underwriters who participated in the IPO
Lawsuit filing date	November 2018
Loss contingency, domicile of litigation	Circuit Court of Hamilton County, Tennessee, U.S. District Court for the Eastern District of Tennessee and Supreme Court of the State of New York
Loss contingency, opinion of counsel	Tennessee State Court CasesThe Consolidated Amended Class Action Complaint (the “Consolidated State Court Complaint”) filed on May 10, 2019 in the Circuit Court of Hamilton County, Tennessee against U.S. Xpress, five officers or directors, and the seven underwriters who participated in the IPO, alleges violations of Sections 11, 12(a)(2) and 15 of the Securities Act of 1933 (the “Securities Act”). The lawsuit is purportedly brought on behalf of a putative class.On November 13, 2020, the court presiding over the Tennessee State Court Cases entered an order, granting in part and denying in part the defendants’ Motions to Dismiss the Consolidated State Court Complaint. The court held that the plaintiffs failed to state a claim for violation of the Securities Act with respect to the majority of statements challenged as false or misleading in the Consolidated State Court Complaint. The court, however, held that the Consolidated State Court Complaint sufficiently alleged violations of the Securities Act with respect to one statement from the IPO registration statement and prospectus that the plaintiffs alleged to be false or misleading, both on theories of alleged misrepresentations and material omissions.New York State Court CaseOn March 14, 2019, a substantially similar putative class action complaint was filed in the Supreme Court of the State of New York, County of New York, by a different plaintiff alleging claims under Sections 11 and 15 of the Securities Act against the same defendants as in the Tennessee State Court Cases. On December 18, 2020, defendants filed a Motion to Dismiss or Stay the New York State Case both on the merits and in deference to the pending actions in Tennessee. On March 5, 2021, the court presiding over the New York State Case dismissed the case, and on January 13, 2022, the court entered a motion denying plaintiff’s motion for reconsideration.Federal Court CasesThe operative amended complaint was filed on October 8, 2019 (“Amended Federal Complaint”), which named the same defendants as the Tennessee State Court Cases. The Amended Federal Complaint is made on behalf of a putative class. In addition to claims for alleged violations of Section 11 and 15 of the Securities Act, the Amended Federal Complaint alleges violations of Section 10(b) and 20(a) of the Securities Exchange Act of 1934 (“Exchange Act”) against U.S. Xpress, its Chief Executive Officer and its Chief Financial Officer. On June 30, 2020, the court presiding over the Federal Court Cases issued its ruling granting in part and denying in part the defendants’ Motions to Dismiss the Amended Federal Complaint. The court dismissed entirely the plaintiffs’ claims for alleged violations of the Exchange Act and further held that the plaintiffs failed to state a claim for violation of the Securities Act with respect to the majority of statements challenged as false or misleading in the Amended Federal Complaint. The court, however, held that the Federal Amended Complaint sufficiently alleged violations of the Securities Act with respect to two statements from the IPO registration statement and prospectus that the plaintiffs alleged to be false or misleading, both on theories of alleged misrepresentations and material omissions.SettlementThe parties reached a settlement with the Federal Court and Tennessee State Court plaintiffs. On March 27, 2023, the parties filed the stipulation of settlement with the Federal Court, and on March 28, 2023, the Federal Court entered an order granting preliminary approval of the settlement. The Federal Court entered an order granting final approval of the settlement on July 12, 2023. The monetary component of the settlement in principle is to be paid by the applicable insurance carriers.
[1]Individually and on behalf of all others similarly situated.

Share Repurchase Plans (Details

Share Repurchase Plans (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022		Sep. 30, 2023	Sep. 30, 2022		Dec. 31, 2022	Apr. 19, 2022	Nov. 24, 2020
Class of Stock [Line Items]
Share repurchase, shares		0			6,001
Company shares repurchased		$ 0			$ 299,941
Knight-Swift Share Repurchase Plan, November 24, 2020
Class of Stock [Line Items]
Share repurchase plan, authorized amount, value									$ 250,000
Share repurchase plan, remaining authorized amount, value								$ 42,800
Share repurchase, shares		0			2,821
Company shares repurchased		$ 0			$ 149,982
Knight-Swift Share Repurchase Plan, April 19, 2022
Class of Stock [Line Items]
Share repurchase plan, authorized amount, value								$ 350,000
Share repurchase plan, remaining authorized amount, value	$ 200,000			$ 200,000			$ 200,000
Share repurchase, shares	0	0	[1]	0	3,180	[1]
Company shares repurchased	$ 0	$ 0	[1]	$ 0	$ 149,959	[1]
[1]$200.0 million remained available under the 2022 Knight-Swift Repurchase Plan as of September 30, 2023 and December 31, 2022.

Weighted Average Shares Outst_3

Weighted Average Shares Outstanding (Details) - shares shares in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Earnings Per Share [Abstract]
Basic weighted average common shares outstanding		161,332	160,665	161,124	162,785
Dilutive effect of equity awards		556	907	658	935
Diluted weighted average common shares outstanding		161,888	161,572	161,782	163,720
Anti-dilutive shares excluded from diluted earnings per share	[1]	57	132	141	321
[1]Shares were excluded from the dilutive-effect calculation because the outstanding awards' exercise prices were greater than the average market price of the Company's common stock for the periods presented.

Fair Value Measurement - Estima

Fair Value Measurement - Estimated Fair Values (Details) - USD ($) $ in Thousands		Sep. 30, 2023		Jul. 01, 2023	Dec. 31, 2022
Financial Assets:
Equity method investments		$ 97,878			$ 103,517
Equity method investments (Estimated Fair Value)		97,878			103,517
Investments in equity securities		0			1,668
Convertible note		0			11,341
Financial Liabilities:
Term loan Carrying Value		1,882,152			1,080,462
Revolving line of credit		300,000			43,000
Secured Debt	[1],[2]	296,884			0
Accounts receivable securitization		361,681			418,561
Business Combination, Contingent Consideration, Liability	[3]	40,859			4,217
U.S. Xpress | Class A
Financial Liabilities:
Business Combination, Contingent Consideration, Liability		134,107	[3]	$ 134,100	0	[3]
2021 Term Loan A-2
Financial Liabilities:
Term loan Carrying Value	[4]	199,865			199,755
Term loan, Fair Value	[4]	200,000			200,000
2021 Term Loan A-3
Financial Liabilities:
Term loan Carrying Value	[4]	798,970			798,705
Term loan, Fair Value	[4]	800,000			800,000
2023 Term Loan
Financial Liabilities:
Term loan Carrying Value	[5]	249,054			0
Term loan, Fair Value	[5]	250,000			0
2021 Revolver
Financial Liabilities:
Revolving line of credit		300,000			43,000
2021 Prudential Notes
Financial Liabilities:
Term loan Carrying Value	[6]	28,057			35,960
Term loan, Fair Value	[6]	28,085			36,014
Debt Instrument, Fair Value Disclosure		(1,300)			(1,700)
Deferred loan costs		28			100
2022 RSA
Financial Liabilities:
Accounts receivable securitization	[7]	361,681			418,561
Debt Instrument, Fair Value Disclosure	[7]	(362,000)			(419,000)
Deferred loan costs		300			400
U.S. Xpress Revenue Equipment Installment Notes
Financial Liabilities:
Secured Debt	[8]	$ 296,884			0
Debt Instrument, Fair Value Disclosure					$ (1,600)
[1]Refer to Note 12 for information regarding the fair value of debt.[2]The revenue equipment installment loans were assumed at the close of the U. S. Xpress Acquisition and have a weighted average interest rate of 4.5% as of September 30, 2023.[3]Refer to Note 3 for information regarding the contingent consideration related to the U.S. Xpress Acquisition[4] As of September 30, 2023, the carrying amounts of the 2021 Term Loan A-2 and 2021 Term Loan A-3 were net of $0.1 million and $1.0 million in deferred loan costs, respectively. As of December 31, 2022, the carrying amounts of the 2021 Term Loan A-2 and 2021 Term Loan A-3 were As of September 30, 2023, the carrying amount of the 2021 Prudential Notes was net of approximately $28,000 i n deferred loan costs and included $1.3 million in fair value adjustments. As of December 31, 2022, the carrying amount of the 2021 Prudential Notes was net of $0.1 million in deferred loan costs and included $1.7 million in fair value adjustments. The carrying amount of the 2022 RSA was net of $0.3 million and $0.4 million in deferred loan costs as of September 30, 2023 and December 31, 2022, respectively.

Fair Value Measurement - Recurr

Fair Value Measurement - Recurring and Nonrecurring Measurements (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended			12 Months Ended
		Sep. 30, 2023		Sep. 30, 2022	Sep. 30, 2023		Sep. 30, 2022	Dec. 31, 2022		Jul. 01, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible note		$ 0			$ 0			$ 11,341
Debt and Equity Securities, Gain (Loss)					2,100		$ (51,033)
Business Combination, Contingent Consideration, Liability	[1]	40,859			40,859			4,217
Asset Impairment Charges		0		$ 0	0		(810)
Gain (Loss) on Disposition of Property Plant Equipment					46,628		73,373
U.S. Xpress | Class A
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability		134,107	[1]		134,107	[1]		0	[1]	$ 134,100
Equipment [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gain (Loss) on Disposition of Property Plant Equipment		11,400		15,600	46,600		73,400
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible note	[2]							11,341
Gross Unrealized Gains	[2]							1,341
Assets, Fair Value Disclosure	[3]							1,668
Fair Value, Option, Changes in Fair Value, Gain (Loss)	[3]							(50,918)
Gain (Loss) on Investments				300			900
Debt and Equity Securities, Gain (Loss)				500			(51,000)
Debt and Equity Securities, Unrealized Gain (Loss)				(6,500)			(62,400)
Debt and Equity Securities, Realized Gain (Loss)				7,000			11,400
Business Combination, Contingent Consideration, Liability	[4]	40,859	[5]		40,859	[5]		4,217
Contingent Consideration Gain (Loss)		900		$ 0	3,359	[4],[5]	$ 0	0	[4]
Total pension plan assets		50,974			50,974			52,535
Fair Value, Recurring [Member] | U.S. Xpress | Class A
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability	[5]	134,107			134,107
Contingent Consideration Gain (Loss)	[5]				0
Fair Value, Recurring [Member] | US equity funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets								10,901
Fair Value, Recurring [Member] | International equity funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets								4,828
Fair Value, Recurring [Member] | Fixed income funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets		50,587			50,587			34,728
Fair Value, Recurring [Member] | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets		387			387			2,078
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible note	[2]							0
Assets, Fair Value Disclosure	[3]							1,668
Business Combination, Contingent Consideration, Liability	[4]	0	[5]		0	[5]		0
Total pension plan assets		50,974			50,974			52,535
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Xpress | Class A
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability	[5]	0			0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | US equity funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets								10,901
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | International equity funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets								4,828
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Fixed income funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets		50,587			50,587			34,728
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets		387			387			2,078
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible note	[2]							0
Assets, Fair Value Disclosure	[3]							0
Business Combination, Contingent Consideration, Liability	[4]	0	[5]		0	[5]		0
Total pension plan assets		0			0			0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Xpress | Class A
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability	[5]	0			0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | US equity funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets								0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | International equity funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets								0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Fixed income funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets		0			0			0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets		0			0			0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible note	[2]							11,341
Assets, Fair Value Disclosure	[3]							0
Business Combination, Contingent Consideration, Liability	[4]	40,859	[5]		40,859	[5]		4,217
Total pension plan assets		0			0			0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Xpress | Class A
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability	[5]	134,107			134,107
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | US equity funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets								0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | International equity funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets								0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Fixed income funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets		0			0			0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total pension plan assets		0			0			0
Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure		0			0
Financial and Nonfinancial Liabilities, Fair Value Disclosure		$ 0			$ 0			0
Building and Building Improvements | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	[6]							0
Asset Impairment Charges	[6]							(810)
Building and Building Improvements | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	[6]							0
Building and Building Improvements | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	[6]							0
Building and Building Improvements | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	[6]							$ 0
[1]Refer to Note 3 for information regarding the contingent consideration related to the U.S. Xpress Acquisition[2] Convertible notes — The condensed consolidated statements of comprehensive income include the fair value activities from the Company's convertible notes within "Other income (expenses), net". The estimated fair value is based on probability-weighted discounted cash flow analysis of the corresponding pay-off/redemption. • Quarter Ended Gain (Loss) Activities: The Company recognized an unrealized gain of $0.3 million during the quarter ended September 30, 2022. • Year-to-date Gain (Loss) Activities: The Company recognized an unrealized gain of $0.9 million during the year-to-date period ended September 30, 2022. Investments in equity securities — The condensed consolidated statements of comprehensive income include the fair value activities from the Company's investments in equity securities within "Other income (expenses), net". The estimated fair value is based on quoted prices in active markets that are readily and regularly obtainable. • Quarter Ended Gain (Loss) Activities: During the quarter ended September 30, 2022, the Company recognized a gain of $0.5 million, which consisted of $7.0 million in realized gains from the Company's other investments in equity securities. This was partially offset by $6.5 million in unrealized losses, primarily from mark-to-market adjustments of the Company's equity investment in Embark. • Year-to-date Gain (Loss) Activities: During the year-to-date period ended September 30, 2022, the Company recognized a loss of $51.0 million, which consisted of $62.4 million in unrealized losses, primarily from mark-to-market adjustments of the Company's investment in Embark. This was partially offset by $11.4 million realized gains from the Company's other investments in equity securities.

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Related Party Transaction [Line Items]
Total revenue		$ 2,019,936	$ 1,896,839	$ 5,209,847	$ 5,684,959
Costs and Expenses		1,938,880	1,631,398	4,889,974	4,795,654
Trade receivables, net of allowance for doubtful accounts of $29,144 and $22,980, respectively		971,175		971,175		$ 842,294
Accounts payable		299,039		299,039		220,849
Gross property and equipment		6,542,804		6,542,804		5,740,383
Certain Affiliates [Member]
Related Party Transaction [Line Items]
Trade receivables, net of allowance for doubtful accounts of $29,144 and $22,980, respectively	[1]	0		0		24
Accounts payable	[1]	40		40		$ 39
Certain Affiliates [Member] | Facility and Equipment Leases [Member]
Related Party Transaction [Line Items]
Total revenue		0	0	0	0
Costs and Expenses		21	78	67	263
Certain Affiliates [Member] | Other Services [Member]
Related Party Transaction [Line Items]
Total revenue		0	20	27	58
Costs and Expenses		9	$ 9	402	$ 27
Certain Affiliates [Member] | Equipment Purchase
Related Party Transaction [Line Items]
Gross property and equipment		$ 6,000		$ 6,000
[1]"Certain affiliates" includes entities that are associated with various board members and executives and require approval by the Audit Committee of the Board prior to completing transactions. Transactions with these entities generally include facility and equipment leases, equipment sales, and other services.

Information by Segment and Ge_3

Information by Segment and Geography - Segment Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Total revenue	$ 2,019,936	$ 1,896,839	$ 5,209,847	$ 5,684,959
Operating income	81,056	265,441	319,873	889,305
Depreciation and amortization of property and equipment	176,613	150,363	488,960	442,889
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenue	1,925,657	1,780,800	4,887,095	5,361,906
Operating income	86,476	246,954	347,962	841,203
Depreciation and amortization of property and equipment	159,085	135,535	436,564	398,426
Operating Segments [Member] | Truckload [Member]
Segment Reporting Information [Line Items]
Total revenue	1,380,781	1,160,735	3,346,685	3,430,075
Operating income	48,361	175,802	232,171	587,215
Depreciation and amortization of property and equipment	135,774	114,946	369,006	338,014
Operating Segments [Member] | LTL
Segment Reporting Information [Line Items]
Total revenue	284,168	278,615	806,577	817,587
Operating income	32,275	30,859	89,095	101,003
Depreciation and amortization of property and equipment	17,069	15,699	50,077	46,280
Operating Segments [Member] | Logistics [Member]
Segment Reporting Information [Line Items]
Total revenue	159,489	210,673	417,715	741,374
Operating income	10,364	27,459	32,750	110,809
Depreciation and amortization of property and equipment	1,048	566	3,078	1,708
Operating Segments [Member] | Intermodal [Member]
Segment Reporting Information [Line Items]
Total revenue	101,219	130,777	316,118	372,870
Operating income	(4,524)	12,834	(6,054)	42,176
Depreciation and amortization of property and equipment	5,194	4,324	14,403	12,424
Non-reportable segments [Member]
Segment Reporting Information [Line Items]
Total revenue	119,677	139,435	391,773	385,186
Operating income	(5,420)	18,487	(28,089)	48,102
Depreciation and amortization of property and equipment	17,528	14,828	52,396	44,463
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenue	$ (25,398)	$ (23,396)	$ (69,021)	$ (62,133)

Information by Segment and Ge_4

Information by Segment and Geography - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Segment Reporting [Abstract]
Percentages Of Foreign Operations Consolidated Revenue	5%	5%	5%	5%
Long lived assets of foreign operations	5%		5%		5%