Knight-Swift Transportation (KNX) 10-Q 7 Aug 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Jul. 31, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2019
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	20002 North 19th Avenue
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		170,511,687
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Entity Central Index Key	0001492691
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands		Jun. 30, 2019		Dec. 31, 2018
Current assets:
Cash and cash equivalents		$ 55,063		$ 82,486
Cash and cash equivalents – restricted	[1]	51,602		46,888
Restricted investments, held-to-maturity, amortized cost	[2]	10,277		17,413
Trade receivables, net of allowance for doubtful accounts of $17,350 and $16,355, respectively		549,668		601,228
Contract balance – revenue in transit		20,526		15,602
Prepaid expenses		67,904	[3]	67,011	[4]
Assets held for sale		43,479		39,955
Income tax receivable		35,437		6,943
Other current assets		34,356		29,706
Total current assets		868,312		907,232
Gross property and equipment		3,546,930	[5]	3,305,944
Less: accumulated depreciation and amortization		(801,287)	[5]	(693,107)
Property and equipment, net		2,745,643		2,612,837
Operating lease right-of-use assets		221,026	[6]	0	[7]
Goodwill		2,919,219		2,919,176
Intangible assets, net		1,399,534		1,420,919
Other long-term assets		59,850	[3]	51,721	[4]
Total assets		8,213,584		7,911,885
Current liabilities:
Accounts payable		165,085	[3]	117,883	[4]
Accrued payroll and purchased transportation		112,949		126,464
Accrued liabilities		154,197	[3]	151,500	[4]
Claims accruals – current portion		153,768		160,044
Finance lease liabilities and long-term debt – current portion		58,684	[5]	58,672
Operating lease liabilities – current portion		98,904	[6]	0	[7]
Total current liabilities		743,587		614,563
Revolving line of credit		270,000		195,000
Long-term debt – less current portion		364,707		364,590
Finance lease liabilities – less current portion		66,027		71,248
Operating lease liabilities – less current portion		129,680	[6]	0	[7]
Accounts receivable securitization		144,684		239,606
Claims accruals – less current portion		196,929		201,327
Deferred tax liabilities		749,077	[8]	739,538	[9]
Other long-term liabilities		16,873	[3]	23,294	[4]
Total liabilities		2,681,564		2,449,166
Commitments and contingencies (Notes 11 and 12)
Stockholders’ equity:
Preferred stock, par value $0.01 per share; 10,000 shares authorized; none issued		0		0
Common stock, par value $0.01 per share; 500,000 shares authorized; 170,378 and 172,844 shares issued and outstanding as of June 30, 2019 and December 31, 2018, respectively.		1,703		1,728
Additional paid-in capital		4,254,297		4,242,369
Retained earnings		1,274,067		1,216,852
Total Knight-Swift stockholders' equity		5,530,067		5,460,949
Noncontrolling interest		1,953		1,770
Total stockholders’ equity		5,532,020		5,462,719
Total liabilities and stockholders’ equity		8,213,584		7,911,885
Common Class A [Member]
Stockholders’ equity:
Total stockholders’ equity		$ 1,703		$ 1,728
[1]	Reflects cash and cash equivalents that are primarily restricted for claims payments.
[2]	Refer to Note 5 for the differences between the carrying amounts and estimated fair values of the Company's restricted investments, held-to-maturity.
[3]	Refer to tabular footnote (2) under "Adoption Date Impact" above.
[4]	The effect of adopting ASC Topic 842 reflects certain reclassifications to adjust the right-of-use assets.
[5]	Amounts represent reclassification of operating lease liabilities to finance lease liabilities, as the Company became reasonably certain to purchase certain revenue equipment off of operating leases during the second quarter of 2019.
[6]	Refer to tabular footnote (1) under "Adoption Date Impact" above.
[7]	These new line items on the condensed consolidated balance sheets represent the capitalization of the Company's operating leases as lessee.
[8]	Refer to tabular footnote (3) under "Adoption Date Impact" above.
[9]	Amounts are reflective of deferred tax impacts from capitalizing the Company's operating leases

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Accounts Receivable, Allowance for Credit Loss, Current	$ 17,350	$ 16,355
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 Class A [Member]
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)	170,378	172,844
Common stock, shares outstanding (in shares)	170,378	172,844

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Total revenue	$ 1,242,083	$ 1,331,683	$ 2,446,618	$ 2,602,815
Operating expenses:
Salaries, wages, and benefits	380,354	371,405	744,209	733,078
Fuel	151,309	162,969	289,748	307,785
Operations and maintenance	82,443	88,278	162,203	173,298
Insurance and claims	48,796	53,126	98,932	112,274
Operating taxes and licenses	21,560	22,671	43,363	45,821
Communications	4,960	5,450	10,043	10,742
Depreciation and amortization of property and equipment	102,938	95,748	203,875	189,611
Amortization of intangibles	10,692	10,687	21,385	21,196
Rental expense	32,875	47,703	68,420	100,578
Purchased transportation	261,273	335,712	530,622	659,995
Impairments	2,182	0	2,182	0
Miscellaneous operating expenses	34,108	13,692	46,744	30,451
Total operating expenses	1,133,490	1,207,441	2,221,726	2,384,829
Operating income	108,593	124,242	224,892	217,986
Other (expenses) income:
Interest income	977	730	1,993	1,302
Interest expense	(7,156)	(7,132)	(14,504)	(13,896)
Other income, net	3,101	1,005	9,240	3,160
Other (expenses) income, net	(3,078)	(5,397)	(3,271)	(9,434)
Income before income taxes	105,515	118,845	221,621	208,552
Income tax expense	26,076	27,217	53,999	46,192
Net income	79,439	91,628	167,622	162,360
Net income attributable to noncontrolling interest	(234)	(305)	(479)	(673)
Net income attributable to Knight-Swift	$ 79,205	$ 91,323	$ 167,143	$ 161,687
Earnings per share:
Basic (in dollars per share)	$ 0.46	$ 0.51	$ 0.97	$ 0.91
Diluted (in dollars per share)	0.46	0.51	0.97	0.90
Dividends declared per share: (in dollars per share)	$ 0.06	$ 0.06	$ 0.12	$ 0.12
Weighted average shares outstanding:
Basic (in shares)	172,078	178,451	172,522	178,307
Diluted (in shares)	172,724	179,398	173,162	179,321
Revenue, excluding trucking fuel surcharge [Member]
Total revenue	$ 1,122,754	$ 1,191,022	$ 2,219,710	$ 2,333,063
Trucking fuel surcharge revenue [Member]
Total revenue	$ 119,329	$ 140,661	$ 226,908	$ 269,752

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Statement of Cash Flows [Abstract]
Net income	$ 167,622	$ 162,360
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property, equipment, and intangibles	225,260	210,807
Gain on sale of property and equipment	(19,267)	(15,812)
Impairments	2,182	0
Deferred income taxes	9,519	6,558
Non-cash lease expense	59,501	0
Other adjustments to reconcile net income to net cash provided by operating activities	(2,282)	(660)
Increase (decrease) in cash resulting from changes in:
Trade receivables	50,495	9,024
Income tax receivable	(28,494)	25,078
Accounts payable	(25,165)	(14,513)
Accrued liabilities and claims accrual	(16,910)	(6,263)
Operating lease liabilities	(59,745)	0
Other assets and liabilities	96	(667)
Net cash provided by operating activities	362,812	375,912
Cash flows from investing activities:
Proceeds from maturities of held-to-maturity investments	12,945	18,218
Purchases of held-to-maturity investments	(5,847)	(17,454)
Proceeds from sale of property and equipment, including assets held for sale	103,818	99,028
Purchases of property and equipment	(323,722)	(220,414)
Expenditures on assets held for sale	(7,961)	(19,497)
Net cash, restricted cash, and equivalents invested in acquisition	0	(101,693)
Other cash flows from investing activities	(3,115)	9,248
Net cash used in investing activities	(223,882)	(232,564)
Cash flows from financing activities:
Repayment of finance leases and long-term debt	(36,941)	(17,371)
Borrowings (repayments) on revolving line of credit, net	75,000	(5,000)
Borrowings under accounts receivable securitization	90,000	15,000
Repayment of accounts receivable securitization	(185,000)	(105,000)
Proceeds from common stock issued	5,363	10,934
Repurchases of the Company's common stock	(86,892)	0
Dividends paid	(20,952)	(21,731)
Other cash flows from financing activities	(2,600)	(3,601)
Net cash used in financing activities	(162,022)	(126,769)
Net (decrease) increase in cash, restricted cash, and equivalents	(23,092)	16,579
Cash, restricted cash, and equivalents at beginning of period	130,976	151,733
Cash, restricted cash, and equivalents at end of period	107,884	168,312
Cash paid during the period for:
Interest	14,277	13,306
Income taxes	72,467	13,425
Other Significant Noncash Transactions [Line Items]
Equipment acquired included in accounts payable	50,091	32,754
Right-of-use assets obtained in exchange for new operating lease liabilities	8,643	0
Right-of-use assets obtained in exchange for new financing lease liabilities	32,153	0
Financing provided to independent contractors for equipment sold [Member]
Other Significant Noncash Transactions [Line Items]
Other non-cash investing and financing activities	3,204	3,084
Transfers from property and equipment to assets held for sale [Member]
Other Significant Noncash Transactions [Line Items]
Other non-cash investing and financing activities	$ 65,264	$ 48,806

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) Reconciliation of Cash, Restricted Cash, and Cash Equivalents - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Statement of Cash Flows [Abstract]
Cash and cash equivalents		$ 55,063	$ 82,486	$ 115,494	$ 76,649
Cash and cash equivalents – restricted	[1]	51,602	46,888	50,714	73,657
Other long-term assets	[1]	1,219	1,602	2,104	1,427
Cash, restricted cash, and equivalents		$ 107,884	$ 130,976	$ 168,312	$ 151,733
[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]	Total Knight-Swift Equity [Member]	Noncontrolling Interest [Member]	Common Class A [Member]
Beginning balance, shares at Dec. 31, 2017						177,998
Beginning balance, value at Dec. 31, 2017	$ 5,240,370	$ 4,219,214	$ 1,016,738	$ 5,237,732	$ 2,638	$ 1,780
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued to employees (shares)						285
Common stock issued to employees	4,090	4,087		4,090		$ 3
Common stock issued under employee stock purchase plan (shares)						9
Common stock issued under ESPP	371	371		371		$ 0
Shares withheld – RSU settlement	(2,118)		(2,118)	(2,118)
Employee stock-based compensation expense	1,989	1,989		1,989
Cash dividends paid and dividends accrued ($0.06 per share)	(10,742)		(10,742)	(10,742)
Net income attributable to Knight-Swift	70,364		70,364	70,364
Distribution to noncontrolling interest	(801)				(801)
Net income attributable to noncontrolling interest	368				368
Net cumulative-effect adjustment from adopting ASC Topic 606	5,301		5,301	5,301
Ending balance, shares at Mar. 31, 2018						178,292
Ending balance, value at Mar. 31, 2018	5,309,192	4,225,661	1,079,543	5,306,987	2,205	$ 1,783
Beginning balance, shares at Dec. 31, 2017						177,998
Beginning balance, value at Dec. 31, 2017	5,240,370	4,219,214	1,016,738	5,237,732	2,638	$ 1,780
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued to employees (shares)						598
Common stock issued to employees	9,383	9,377		9,383		$ 6
Common stock issued to the Board (Shares)						19
Common stock issued to the Board	774	774		774		$ 0
Common stock issued under employee stock purchase plan (shares)						18
Common stock issued under ESPP	777	777		777		$ 0
Shares withheld – RSU settlement	(2,529)		(2,529)	(2,529)
Employee stock-based compensation expense	4,403	4,403		4,403
Cash dividends paid and dividends accrued ($0.06 per share)	(21,510)		(21,510)	(21,510)
Net income attributable to Knight-Swift	161,687		161,687	161,687
Distribution to noncontrolling interest	(1,072)				(1,072)
Net income attributable to noncontrolling interest	673				673
Net acquisition of remaining ownership interest, previously noncontrolling	(1,873)	(1,873)		(1,873)
Net cumulative-effect adjustment from adopting ASC Topic 606	5,301		5,301	5,301
Ending balance, shares at Jun. 30, 2018						178,633
Ending balance, value at Jun. 30, 2018	5,396,384	4,232,672	1,159,687	5,394,145	2,239	$ 1,786
Beginning balance, shares at Mar. 31, 2018						178,292
Beginning balance, value at Mar. 31, 2018	5,309,192	4,225,661	1,079,543	5,306,987	2,205	$ 1,783
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued to employees (shares)						313
Common stock issued to employees	5,293	5,290		5,293		$ 3
Common stock issued to the Board (Shares)						19
Common stock issued to the Board	774	774		774		$ 0
Common stock issued under employee stock purchase plan (shares)						9
Common stock issued under ESPP	406	406		406		$ 0
Shares withheld – RSU settlement	(411)		(411)	(411)
Employee stock-based compensation expense	2,414	2,414		2,414
Cash dividends paid and dividends accrued ($0.06 per share)	(10,768)		(10,768)	(10,768)
Net income attributable to Knight-Swift	91,323		91,323	91,323
Distribution to noncontrolling interest	(271)				(271)
Net income attributable to noncontrolling interest	305				305
Net acquisition of remaining ownership interest, previously noncontrolling	(1,873)	(1,873)		(1,873)
Ending balance, shares at Jun. 30, 2018						178,633
Ending balance, value at Jun. 30, 2018	5,396,384	4,232,672	1,159,687	5,394,145	2,239	$ 1,786
Beginning balance, shares at Dec. 31, 2018						172,844
Beginning balance, value at Dec. 31, 2018	5,462,719	4,242,369	1,216,852	5,460,949	1,770	$ 1,728
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued to employees (shares)						198
Common stock issued to employees	2,375	2,373		2,375		$ 2
Common stock issued under employee stock purchase plan (shares)						24
Common stock issued under ESPP	566	566		566		$ 0
Shares withheld – RSU settlement	(1,514)		(1,514)	(1,514)
Employee stock-based compensation expense	2,880	2,880		2,880
Cash dividends paid and dividends accrued ($0.06 per share)	(10,438)		(10,438)	(10,438)
Net income attributable to Knight-Swift	87,938		87,938	87,938
Distribution to noncontrolling interest	(148)				(148)
Net income attributable to noncontrolling interest	245				245
Ending balance, shares at Mar. 31, 2019						173,066
Ending balance, value at Mar. 31, 2019	5,544,623	4,248,188	1,292,838	5,542,756	1,867	$ 1,730
Beginning balance, shares at Dec. 31, 2018						172,844
Beginning balance, value at Dec. 31, 2018	5,462,719	4,242,369	1,216,852	5,460,949	1,770	$ 1,728
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued to employees (shares)						347
Common stock issued to employees	3,703	3,700		3,703		$ 3
Common stock issued to the Board (Shares)						19
Common stock issued to the Board	531	531		531		$ 0
Common stock issued under employee stock purchase plan (shares)						42
Common stock issued under ESPP	$ 1,129	1,128		1,129		$ 1
Share repurchase, shares	(2,874)					(2,874)
Company shares repurchased	$ (86,892)		(86,863)	(86,892)		$ (29)
Shares withheld – RSU settlement	(2,304)		(2,304)	(2,304)
Employee stock-based compensation expense	6,569	6,569		6,569
Cash dividends paid and dividends accrued ($0.06 per share)	(20,761)		(20,761)	(20,761)
Net income attributable to Knight-Swift	167,143		167,143	167,143
Distribution to noncontrolling interest	(296)				(296)
Net income attributable to noncontrolling interest	479				479
Ending balance, shares at Jun. 30, 2019						170,378
Ending balance, value at Jun. 30, 2019	5,532,020	4,254,297	1,274,067	5,530,067	1,953	$ 1,703
Beginning balance, shares at Mar. 31, 2019						173,066
Beginning balance, value at Mar. 31, 2019	5,544,623	4,248,188	1,292,838	5,542,756	1,867	$ 1,730
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued to employees (shares)						149
Common stock issued to employees	1,328	1,327		1,328		$ 1
Common stock issued to the Board (Shares)						19
Common stock issued to the Board	531	531		531		$ 0
Common stock issued under employee stock purchase plan (shares)						18
Common stock issued under ESPP	$ 563	562		563		$ 1
Share repurchase, shares	(2,874)					(2,874)
Company shares repurchased	$ (86,892)		(86,863)	(86,892)		$ (29)
Shares withheld – RSU settlement	(790)		(790)	(790)
Employee stock-based compensation expense	3,689	3,689		3,689
Cash dividends paid and dividends accrued ($0.06 per share)	(10,323)		(10,323)	(10,323)
Net income attributable to Knight-Swift	79,205		79,205	79,205
Distribution to noncontrolling interest	(148)				(148)
Net income attributable to noncontrolling interest	234				234
Ending balance, shares at Jun. 30, 2019						170,378
Ending balance, value at Jun. 30, 2019	$ 5,532,020	$ 4,254,297	$ 1,274,067	$ 5,530,067	$ 1,953	$ 1,703

Introduction and Basis of Prese

Introduction and Basis of Presentation	6 Months Ended
	Jun. 30, 2019
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 first half of 2019 , the Company operated an average of 18,959 tractors (comprised of 16,352 company tractors and 2,607 independent contractor tractors) and 56,902 trailers within the Trucking segment. Additionally, the Company operated an average of 672 tractors and 9,864 containers in the Intermodal segment d uring the first half of 2019 . The Company's three reportable segments are Trucking, Logistics, and Intermodal. Segment Realignment During the first quarter of 2019, the Company reorganized its reportable segments to reflect management’s revised reporting structure. Under this revised reporting structure, the Company's three reportable segments, are as follows: • The Trucking segment now includes the results of the previously-reported Knight Trucking, Swift Truckload, Swift Dedicated, and Swift Refrigerated segments. • The Logistics segment now includes the results of the Knight brokerage and Swift logistics businesses which were previously included within the Knight Logistics and Swift non-reportable segments, respectively. • The Intermodal segment now includes the results of the previously-reported Swift Intermodal segment and the results of the Knight intermodal business, which was previously included in the Knight Logistics segment. The non-reportable segments continue to include support services that Swift's subsidiaries provide to customers and independent contractors (including repair and maintenance shop services, equipment leasing, and insurance), as well as certain legal settlements and accruals, amortization of intangibles related to the 2017 Merger, and certain other corporate expenses. Additionally, the non-reportable segments now include Knight's equipment leasing and warranty services to independent contractors and trailer parts manufacturing, which were previously reported within the Knight Logistics segment. Abilene Acquisition On March 16, 2018, the Company acquired all of the issued and outstanding equity interests of Abilene. Abilene's trucking and logistics businesses are included under the respective segments. Please refer to Note 4 for more information about the Abilene Acquisition. Basis of Presentation The condensed consolidated financial statements and footnotes included in this Quarterly Report should be read in conjunction with the consolidated financial statements and footnotes included in Knight-Swift's 2018 Annual Report. The condensed consolidated financial statements in this Quarterly Report include the accounts of Knight-Swift Transportation Holdings Inc. and its subsidiaries. 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 the results of operations of Abilene and its subsidiaries on and prior to its acquisition by the Company on March 16, 2018 in accordance with the accounting treatment applicable to the transaction. Changes in Presentation Changes in presentation associated with adopting accounting pronouncements are included in Note 2. Beginning in the second quarter of 2019, the Company presents "Contract balance – revenue in transit" as a separate line item on the condensed consolidated balance sheets to improve visibility. The balance was previously disclosed within the footnotes to the condensed consolidated financial statements. Prior period amounts have been reclassified out of "Trade receivables, net" to align with the current period presentation. Beginning in the second quarter of 2019, the Company presents fuel surcharge revenue generated within only its Trucking segment within "Trucking fuel surcharge" in the condensed consolidated statements of comprehensive income. Fuel surcharge revenue generated within the remaining segments is included in "Revenue, excluding trucking fuel surcharge." Prior period amounts have been reclassified to align with the current period presentation. Seasonality In the 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 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).

Recently Adopted Accounting Pro

Recently Adopted Accounting Pronouncements	6 Months Ended
	Jun. 30, 2019
Accounting Changes and Error Corrections [Abstract]
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements Leases (ASC Topic 842): ASU 2016-02 — Leases Note: Required annual disclosures regarding ASC Topic 842 are included in Note 9 . Summary of the Standard — In February 2016, the FASB issued ASU 2016-02, which established the new ASC Topic 842, Leases , standard. The new standard requires lessees to recognize assets and liabilities arising from both operating and financing leases on the balance sheet. Lessor accounting for leases is largely unaffected. For public business entities, the new standard was effective for fiscal years beginning after December 15, 2018. Companies may apply the amendments in ASU 2016-02 using a modified retrospective approach with an adjustment to retained earnings as of either the beginning of the current year ("ASC Topic 840 Comparative Approach") or the beginning of the earliest period presented ("ASC Topic 842 Comparative Approach"). Adoption Method and Approach — The Company adopted ASC Topic 842 on January 1, 2019 by applying the ASC Topic 840 Comparative Approach, resulting in the recognition of right-of-use assets and lease liabilities related to its operating leases. Comparative information related to periods prior to January 1, 2019 continues to be reported under the legacy guidance in ASC Topic 840. Practical Expedients — As permitted under ASU 2016-02 (and related ASUs), management elected to apply the package of practical expedients: • Lease Identification — An entity need not reassess whether any expired or existing contracts are or contain leases . • Lease Classification — An entity need not reassess the lease classification for any expired or existing leases (for example, all existing leases that were classified as operating leases in accordance with ASC Topic 840 are now classified as operating leases, and all existing leases that were classified as capital leases in accordance with ASC Topic 840 are now classified as finance leases). • Initial Direct Costs — An entity need not reassess initial direct costs for any existing leases. Adoption Date Impact — The required disclosures regarding the adoption date impact of ASC Topic 842 on the condensed consolidated balance sheet are presented below. December 31, Opening Balance Adjustments January 1, (in thousands) Assets Prepaid expenses 2 $ 67,011 $ (948 ) $ 66,063 Operating lease right-of-use assets 1 — 280,527 280,527 Other long-term assets 2 51,721 (1 ) 51,720 Liabilities Accounts payable 2 $ 117,883 $ (437 ) $ 117,446 Accrued liabilities 2 151,500 (4,168 ) 147,332 Operating lease liabilities – current portion 1 — 119,963 119,963 Operating lease liabilities – less current portion 1 — 168,232 168,232 Deferred tax liabilities 3 739,538 — 739,538 Other long-term liabilities 2 23,294 (4,012 ) 19,282 1 These new line items on the condensed consolidated balance sheets represent the capitalization of the Company's operating leases as lessee. 2 The effect of adopting ASC Topic 842 reflects certain reclassifications to adjust the right-of-use assets. 3 Amounts are reflective of deferred tax impacts from capitalizing the Company's operating leases. Current Period Impact of Adoption — The required quantitative disclosures regarding the current period impact of adopting ASC Topic 842 on the condensed consolidated balance sheet are presented below. June 30, 2019 As Reported under ASC Topic 842 If Reported Under ASC Topic 840 Effect of Change to ASC Topic 842 (in thousands) Assets Prepaid expenses 2 $ 67,904 $ 68,334 $ (430 ) Gross property and equipment 4 3,546,930 3,513,658 33,272 Accumulated depreciation and amortization 4 (801,287 ) (800,165 ) (1,122 ) Operating lease right-of-use assets 1 221,026 — 221,026 Other long-term assets 2 59,850 59,851 (1 ) Liabilities Accounts payable 2 $ 165,085 $ 166,146 $ (1,061 ) Accrued liabilities 2 154,197 157,980 (3,783 ) Finance lease liabilities and long-term debt – current portion 4 58,684 26,531 32,153 Operating lease liabilities – current portion 1 98,904 — 98,904 Operating lease liabilities – less current portion 1 129,680 — 129,680 Deferred tax liabilities 3 749,077 749,136 (59 ) Other long-term liabilities 2 16,873 19,962 (3,089 ) 1 Refer to tabular footnote (1) under "Adoption Date Impact" above. 2 Refer to tabular footnote (2) under "Adoption Date Impact" above. 3 Refer to tabular footnote (3) under "Adoption Date Impact" above. 4 Amounts represent reclassification of operating lease liabilities to finance lease liabilities, as the Company became reasonably certain to purchase certain revenue equipment off of operating leases during the second quarter of 2019. ASU 2018-13: Fair Value Measurement (Topic 820): Disclosure Framework – Change to the Disclosure Requirements for Fair Value Measurement Summary of the Standard — The amendments in this ASU modify several disclosure requirements under ASC Topic 820. These changes include removing the disclosure requirements related to the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, and adding disclosure requirements about the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. Additionally, the amendments remove the phrase "at a minimum" from the codification clarifying that materiality should be considered when evaluating disclosure requirements. Current Period Impact of Adoption — The Company began excluding immaterial disclosures regarding fair value measurements from its Quarterly Reports and Annual Reports during the first quarter of 2019. Other ASUs There were various other ASUs that became effective during year-to-date June 30, 2019 , which did not have a material impact on the Company's results of operations, financial position, cash flows, or disclosures. Recently Issued Accounting Pronouncements Date Issued Reference Description Adoption Date and Method Financial Statement Impact July 2019 2019-07: Codification Updates to SEC Sections — Amendments to SEC Paragraphs Pursuant to SEC Final Rule Releases No. 33-10532, Disclosure Update and Simplification, and Nos. 33-10231 and 33-10442, Investment Company Reporting Modernization, and Miscellaneous Updates 1 The amendments in this ASU update several topics of the ASC to incorporate changes required by guidance made effective by SEC Final Rule Nos. 33-10532, 33-10231, and 33-10442. These final rules included extending the disclosure requirement of presenting changes in stockholders' equity for both current and comparative interim periods, changing the title of the income statement to statement of comprehensive income, and disclosing the dividend per share amount for each class of stock. July 2019, prospective adoption Presentation and disclosure impact only May 2019 2019-05: Financial Instruments —Credit Losses, Topic 326; Targeted Transition Relief 2 The amendments provide entities that hold instruments within the scope of Subtopic 326-20 with the option to irrevocably elect the fair value option in Subtopic 825-10. This fair value option election does not apply to instruments classified as held-to-maturity debt securities. January 2020, Adoption method varies by amendment Currently under evaluation, but not expected to be material April 2019 2019-04: Codification Improvements to Topic 326, Financial Instruments —Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments 2 The amendments address certain issues related to the implementation of ASU 2016-01 – Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, ASU 2016-13 – Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, and ASU 2017-12 – Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities. The amendments update the treatment of credit losses for accrued interest receivables and related recoveries, remove the prohibition of using projections of future interest rate environments when using a discounted cash flow method to measure expected credit losses, as well as outline other targeted improvements that clarify language and intent, better define scope and improve cross references, among others. The amendments in the ASU are effective for fiscal years beginning after December 15, 2019 and early adoption is permitted. January 2020, Adoption method varies by amendment Currently under evaluation, but not expected to be material Date Issued Reference Description Adoption Date and Method Financial Statement Impact March 2019 2019-01: Leases (Topic 842) – Codification Improvements 3 The amendments address certain issues related to the implementation of ASC Topic 842, including; determining the fair value of the underlying asset by lessors that are not manufacturers or dealers, presentation on the statement of cash flows for sales type and direct financing leases, and transition disclosures related to ASC Topic 250. The transition disclosures related to ASC Topic 250 clarify that entities are not required to disclose the impacts of adopting ASC Topic 842 on net income or related per share amounts in both interim and annual reporting periods. The amendments in this ASU are effective for fiscal years beginning after December 15, 2019. January 2019, Adoption method varies by amendment The Company will not disclose the impacts of adopting ASC Topic 842 on net income or related per share amounts. 1 The Company applied the relevant changes during the first quarter of 2019, in conjunction with the effective date per the final SEC rules. Given that the corresponding ASU was issued in July 2019, the amendments in the ASU will technically be adopted in the third quarter of 2019. 2 Not yet adopted. 3 Adopted during the first quarter of 2019.

Recently Issued Accounting Pron

Recently Issued Accounting Pronouncements	6 Months Ended
	Jun. 30, 2019
Accounting Changes and Error Corrections [Abstract]
Recently Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements Leases (ASC Topic 842): ASU 2016-02 — Leases Note: Required annual disclosures regarding ASC Topic 842 are included in Note 9 . Summary of the Standard — In February 2016, the FASB issued ASU 2016-02, which established the new ASC Topic 842, Leases , standard. The new standard requires lessees to recognize assets and liabilities arising from both operating and financing leases on the balance sheet. Lessor accounting for leases is largely unaffected. For public business entities, the new standard was effective for fiscal years beginning after December 15, 2018. Companies may apply the amendments in ASU 2016-02 using a modified retrospective approach with an adjustment to retained earnings as of either the beginning of the current year ("ASC Topic 840 Comparative Approach") or the beginning of the earliest period presented ("ASC Topic 842 Comparative Approach"). Adoption Method and Approach — The Company adopted ASC Topic 842 on January 1, 2019 by applying the ASC Topic 840 Comparative Approach, resulting in the recognition of right-of-use assets and lease liabilities related to its operating leases. Comparative information related to periods prior to January 1, 2019 continues to be reported under the legacy guidance in ASC Topic 840. Practical Expedients — As permitted under ASU 2016-02 (and related ASUs), management elected to apply the package of practical expedients: • Lease Identification — An entity need not reassess whether any expired or existing contracts are or contain leases . • Lease Classification — An entity need not reassess the lease classification for any expired or existing leases (for example, all existing leases that were classified as operating leases in accordance with ASC Topic 840 are now classified as operating leases, and all existing leases that were classified as capital leases in accordance with ASC Topic 840 are now classified as finance leases). • Initial Direct Costs — An entity need not reassess initial direct costs for any existing leases. Adoption Date Impact — The required disclosures regarding the adoption date impact of ASC Topic 842 on the condensed consolidated balance sheet are presented below. December 31, Opening Balance Adjustments January 1, (in thousands) Assets Prepaid expenses 2 $ 67,011 $ (948 ) $ 66,063 Operating lease right-of-use assets 1 — 280,527 280,527 Other long-term assets 2 51,721 (1 ) 51,720 Liabilities Accounts payable 2 $ 117,883 $ (437 ) $ 117,446 Accrued liabilities 2 151,500 (4,168 ) 147,332 Operating lease liabilities – current portion 1 — 119,963 119,963 Operating lease liabilities – less current portion 1 — 168,232 168,232 Deferred tax liabilities 3 739,538 — 739,538 Other long-term liabilities 2 23,294 (4,012 ) 19,282 1 These new line items on the condensed consolidated balance sheets represent the capitalization of the Company's operating leases as lessee. 2 The effect of adopting ASC Topic 842 reflects certain reclassifications to adjust the right-of-use assets. 3 Amounts are reflective of deferred tax impacts from capitalizing the Company's operating leases. Current Period Impact of Adoption — The required quantitative disclosures regarding the current period impact of adopting ASC Topic 842 on the condensed consolidated balance sheet are presented below. June 30, 2019 As Reported under ASC Topic 842 If Reported Under ASC Topic 840 Effect of Change to ASC Topic 842 (in thousands) Assets Prepaid expenses 2 $ 67,904 $ 68,334 $ (430 ) Gross property and equipment 4 3,546,930 3,513,658 33,272 Accumulated depreciation and amortization 4 (801,287 ) (800,165 ) (1,122 ) Operating lease right-of-use assets 1 221,026 — 221,026 Other long-term assets 2 59,850 59,851 (1 ) Liabilities Accounts payable 2 $ 165,085 $ 166,146 $ (1,061 ) Accrued liabilities 2 154,197 157,980 (3,783 ) Finance lease liabilities and long-term debt – current portion 4 58,684 26,531 32,153 Operating lease liabilities – current portion 1 98,904 — 98,904 Operating lease liabilities – less current portion 1 129,680 — 129,680 Deferred tax liabilities 3 749,077 749,136 (59 ) Other long-term liabilities 2 16,873 19,962 (3,089 ) 1 Refer to tabular footnote (1) under "Adoption Date Impact" above. 2 Refer to tabular footnote (2) under "Adoption Date Impact" above. 3 Refer to tabular footnote (3) under "Adoption Date Impact" above. 4 Amounts represent reclassification of operating lease liabilities to finance lease liabilities, as the Company became reasonably certain to purchase certain revenue equipment off of operating leases during the second quarter of 2019. ASU 2018-13: Fair Value Measurement (Topic 820): Disclosure Framework – Change to the Disclosure Requirements for Fair Value Measurement Summary of the Standard — The amendments in this ASU modify several disclosure requirements under ASC Topic 820. These changes include removing the disclosure requirements related to the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, and adding disclosure requirements about the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. Additionally, the amendments remove the phrase "at a minimum" from the codification clarifying that materiality should be considered when evaluating disclosure requirements. Current Period Impact of Adoption — The Company began excluding immaterial disclosures regarding fair value measurements from its Quarterly Reports and Annual Reports during the first quarter of 2019. Other ASUs There were various other ASUs that became effective during year-to-date June 30, 2019 , which did not have a material impact on the Company's results of operations, financial position, cash flows, or disclosures. Recently Issued Accounting Pronouncements Date Issued Reference Description Adoption Date and Method Financial Statement Impact July 2019 2019-07: Codification Updates to SEC Sections — Amendments to SEC Paragraphs Pursuant to SEC Final Rule Releases No. 33-10532, Disclosure Update and Simplification, and Nos. 33-10231 and 33-10442, Investment Company Reporting Modernization, and Miscellaneous Updates 1 The amendments in this ASU update several topics of the ASC to incorporate changes required by guidance made effective by SEC Final Rule Nos. 33-10532, 33-10231, and 33-10442. These final rules included extending the disclosure requirement of presenting changes in stockholders' equity for both current and comparative interim periods, changing the title of the income statement to statement of comprehensive income, and disclosing the dividend per share amount for each class of stock. July 2019, prospective adoption Presentation and disclosure impact only May 2019 2019-05: Financial Instruments —Credit Losses, Topic 326; Targeted Transition Relief 2 The amendments provide entities that hold instruments within the scope of Subtopic 326-20 with the option to irrevocably elect the fair value option in Subtopic 825-10. This fair value option election does not apply to instruments classified as held-to-maturity debt securities. January 2020, Adoption method varies by amendment Currently under evaluation, but not expected to be material April 2019 2019-04: Codification Improvements to Topic 326, Financial Instruments —Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments 2 The amendments address certain issues related to the implementation of ASU 2016-01 – Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, ASU 2016-13 – Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, and ASU 2017-12 – Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities. The amendments update the treatment of credit losses for accrued interest receivables and related recoveries, remove the prohibition of using projections of future interest rate environments when using a discounted cash flow method to measure expected credit losses, as well as outline other targeted improvements that clarify language and intent, better define scope and improve cross references, among others. The amendments in the ASU are effective for fiscal years beginning after December 15, 2019 and early adoption is permitted. January 2020, Adoption method varies by amendment Currently under evaluation, but not expected to be material Date Issued Reference Description Adoption Date and Method Financial Statement Impact March 2019 2019-01: Leases (Topic 842) – Codification Improvements 3 The amendments address certain issues related to the implementation of ASC Topic 842, including; determining the fair value of the underlying asset by lessors that are not manufacturers or dealers, presentation on the statement of cash flows for sales type and direct financing leases, and transition disclosures related to ASC Topic 250. The transition disclosures related to ASC Topic 250 clarify that entities are not required to disclose the impacts of adopting ASC Topic 842 on net income or related per share amounts in both interim and annual reporting periods. The amendments in this ASU are effective for fiscal years beginning after December 15, 2019. January 2019, Adoption method varies by amendment The Company will not disclose the impacts of adopting ASC Topic 842 on net income or related per share amounts. 1 The Company applied the relevant changes during the first quarter of 2019, in conjunction with the effective date per the final SEC rules. Given that the corresponding ASU was issued in July 2019, the amendments in the ASU will technically be adopted in the third quarter of 2019. 2 Not yet adopted. 3 Adopted during the first quarter of 2019.

Abilene Acquisition

Abilene Acquisition	6 Months Ended
	Jun. 30, 2019
Business Combinations [Abstract]
Abilene Acquisition	Abilene Acquisition Information about the accounting treatment for the Abilene Acquisition including details of the transaction, determination of the total fair value consideration, allocation of the purchase price at the end of the measurement period are included in the Company’s Quarterly Report for the quarter ended March 31, 2019. The following unaudited pro forma information combines the historical operations of Knight-Swift and Abilene giving effect to the Abilene Acquisition and related transactions as if they had been consummated on January 1, 2018, the beginning of the comparative periods presented. Year-to-Date June 30, 2018 (in thousands, except per share data) Total revenue $ 2,622,456 Net income attributable to Knight-Swift 162,222 Earnings per share – diluted 0.90 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 Abilene during the periods presented that were directly related to the Abilene Acquisition and related income tax effects. The acquisition-related expenses that the Company incurred from the Abilene Acquisition are eliminated from presentation of the unaudited pro forma net income presented above. The unaudited pro forma condensed combined financial information does not purport to represent the actual results of operations that Knight-Swift and Abilene 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 Abilene Acquisition and also does not reflect any restructuring or integration-related costs to achieve those potential cost savings.

Restricted Investments, Held-to

Restricted Investments, Held-to-Maturity	6 Months Ended
	Jun. 30, 2019
Schedule of Investments [Abstract]
Restricted Investments, Held-to-Maturity	Restricted Investments, Held-to-Maturity The following tables present the cost or amortized cost, gross unrealized gains and temporary losses, and estimated fair value of the Company's restricted investments, held-to-maturity: June 30, 2019 Gross Unrealized Cost or Amortized Gains Temporary Estimated Fair Value (In thousands) US corporate securities $ 10,277 $ 6 $ — $ 10,283 Restricted investments, held-to-maturity $ 10,277 $ 6 $ — $ 10,283 December 31, 2018 Gross Unrealized Cost or Amortized Gains Temporary Estimated Fair Value (In thousands) US corporate securities $ 15,296 $ 1 $ (16 ) $ 15,281 Municipal bonds 1,082 — — 1,082 Negotiable certificate of deposits 1,035 — — 1,035 Restricted investments, held-to-maturity $ 17,413 $ 1 $ (16 ) $ 17,398 As of June 30, 2019 , the contractual maturities of the restricted investments, held-to-maturity, were one year or less. There were 2 securities and 20 securities that were in an unrealized loss position for less than twelve months as of June 30, 2019 and December 31, 2018 , respectively. The Company did not recognize any impairment losses related to its held-to-maturity investments during the quarter or year-to-date periods ended June 30, 2019 or 2018 , respectively. Refer to Note 17 for additional information regarding fair value measurements of the Company's investments.

Assets Held for Sale

Assets Held for Sale	6 Months Ended
	Jun. 30, 2019
Property, Plant and Equipment [Abstract]
Assets Held For Sale	Assets Held for Sale The Company expects to sell its assets held for sale, which consist of revenue equipment, within the next twelve months . Revenue equipment held for sale totaled $43.5 million and $40.0 million as of June 30, 2019 and December 31, 2018 , respectively. Net gains on disposals, including disposals of property and equipment classified as assets held for sale, reported in "Miscellaneous operating expenses" in the condensed consolidated statements of comprehensive income, were: • $7.5 million and $9.1 million for the quarter-to-date periods ended June 30, 2019 and 2018 , respectively. • $19.2 million and $16.6 million for the year-to-date periods ended June 30, 2019 and 2018 , respectively. The Company did not recognize any impairment losses related to assets held for sale during the quarter or year-to-date periods ended June 30, 2019 or 2018 .

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	6 Months Ended
	Jun. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill The changes in the carrying amount of goodwill were as follows: (In thousands) Goodwill, balance at December 31, 2018 $ 2,919,176 Amortization relating to deferred tax assets (5 ) Abilene Acquisition ¹ 48 Goodwill, balance at June 30, 2019 $ 2,919,219 1 The goodwill associated with the Abilene Acquisition was allocated to the Trucking segment and was adjusted for equipment losses and claims incurred prior to the acquisition. There were no goodwill impairments recorded during the June 30, 2019 or 2018 quarter or year-to-date periods. Other Intangible Assets Other intangible asset balances were as follows: June 30, December 31, (In thousands) Customer relationships and non-compete: Gross carrying amount $ 838,100 $ 838,100 Accumulated amortization (78,466 ) (57,081 ) Customer relationships and non-compete, net $ 759,634 $ 781,019 Trade names: Gross carrying amount 639,900 639,900 Intangible assets, net $ 1,399,534 $ 1,420,919 As of June 30, 2019 , management anticipates that the composition and amount of amortization associated with intangible assets will be $21.4 million for the remainder of 2019, $42.7 million for each of the years 2020 through 2021, $42.6 million in 2022, and $42.3 million in 2023. Actual amounts of amortization expense may differ from estimated amounts due to additional intangible asset acquisitions, impairment of intangible assets, accelerated amortization of intangible assets, and other events.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Effective Tax Rate — The quarter-to-date June 30, 2019 and June 30, 2018 effective tax rates were 24.7% and 22.9% , respectively. The Company recognized discrete items relating to the partial release of its reserve for uncertain tax positions and stock compensation deductions during the quarter ended June 30, 2019 . The Company also recognized discrete items relating to stock compensation deductions and a favorable audit settlement of nondeductible penalties during the quarter ended June 30, 2018 . The year-to-date June 30, 2019 and June 30, 2018 effective tax rates were 24.4% and 22.1% , respectively. The Company recognized discrete items relating to the partial release of its reserve for uncertain tax positions and stock compensation deductions during the year-to-date period ended June 30, 2019 . The Company also recognized discrete items relating to stock compensation deductions and a favorable audit settlement of nondeductible penalties during the year-to-date June 30, 2018 period. Valuation Allowance — The Company has not established a valuation allowance as it has been determined that, based upon available evidence, a valuation allowance is not required. Management believes that it is more like ly than not that the results of future operations will generate sufficient taxable income to realize the deferred tax assets. All other deferred tax assets are expected to be realized and utilized by continued profitability in future periods. Unrecognized Tax Benefits — During the quarter ended June 30, 2019 , the Company reduced its reserve by $1.0 million for uncertain tax positions relating to various federal credits. Management believes it is reasonably possible that a decrease of up to $1.7 million in unrecognized tax benefits relating to federal credits may be necessary within the next twelve months. Interest and Penalties — Accrued interest and penalties related to unrecognized tax benefits as of June 30, 2019 and December 31, 2018 were approximately $1.0 million and $1.4 million , respectively. Tax Examinations — Certain of the Company's subsidiaries are currently under examination by various state jurisdictions for tax years ranging from 2013 through 2017 . 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 2013 remain subject to examination.

Leases

Leases	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Leases	Leases June 30, 2019 (ASC Topic 842 Disclosures) Lessee Disclosures for Lease Accounting under ASC Topic 842 Accounting Policy — Management evaluates the Company’s leases based on the underlying asset groups. The assets currently underlying the Company’s leases include revenue equipment (primarily tractors and trailers), real estate (primarily buildings, office space, land, and drop yards), as well as technology and other equipment that supports business operations. Management’s significant assumptions and judgments include the determination of the discount rate (discussed below), as well as the determination of whether a contract contains a lease (specifically with respect to whether the Company's drop yard contracts contain identified assets). • Lease Term — The Company’s leases generally have lease terms corresponding to the useful lives of the underlying assets. Revenue equipment leases have fixed payment terms based on the passage of time, which is typically three to five years for tractors and five to seven years for trailers. Certain finance leases for revenue equipment contain renewal or fixed price purchase options. Real estate leases, excluding drop yards, generally have varying lease terms between five and fifteen years and may include renewal options. Drop yards include month-to-month leases, as well as leases with varying lease terms generally ranging from two to five years. Options to renew or purchase the underlying assets are considered in the determination of the right-of-use asset and lease liability once reasonably certain of exercise. • Portfolio Approach — The Company typically leases its revenue equipment under master lease agreements, which contain general terms, conditions, definitions, representations, warranties and other general language, while the specific contract provisions are contained within the various individual lease schedules that fall under a master lease agreement. Each individual leased asset within a lease schedule is similar in nature (i.e. all tractors or all trailers) and has identical contract provisions to all of the other individual leased assets within the same lease schedule (such as the contract provisions discussed above). Management has elected to apply the portfolio approach to its revenue equipment leases, as accounting for its revenue equipment under the portfolio approach would not be materially different from separately accounting for each individual underlying asset as a lease. Each individual real estate and other lease is accounted for at the individual asset level. • Nonlease components — Management has elected to combine its nonlease components (such as fixed charges for common area maintenance, real estate taxes, utilities, and insurance) with lease components for each class of underlying asset, as applicable, as the nonlease components in the Company’s lease contracts typically are not material. These nonlease components are usually present within the Company’s real estate leases. The Company’s assets are generally insured by umbrella policies, in which the premiums change from one policy period to the next, making them variable in nature. Accordingly, these insurance costs are excluded from the Company’s calculation of right-of-use assets and corresponding lease liabilities. • Short-term lease exemption — Management has elected to apply the short-term lease exemption to all asset groups. Accordingly, leases with terms of twelve months or less are not capitalized and continue to be expensed on a straight-line basis over the term of the lease. This primarily affects the Company’s drop yards and corresponding temporary structures on those drop yards. To a lesser extent, certain short-term leases for revenue equipment, technology, and other assets are affected. • Discount rate — The Company uses the rate implicit in the lease, when readily determinable. Otherwise the Company’s incremental borrowing rate is applied. Due to the unique structure of the Company’s revenue equipment leases, management believes that the rate implicit in the lease is readily determinable for such leases and the implicit rate is used. The Company’s use of the implicit rate (rather than the incremental borrowing rate) for its revenue equipment leases does not materially change the Company’s financial position or financial results either by financial statement caption or in total. The implicit interest rate is not readily determinable for the Company’s real estate and other leases. As such, management applies the Company’s incremental borrowing rate, which is defined by GAAP as the rate of interest that the Company would have to pay to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. The Company's incremental borrowing rate is based on the results of an independent third-party valuation. • Residual values — The Company's finance leases are typically structured with balloon payments at the end of the lease term equal to the residual value the Company is contracted to receive from certain equipment manufacturers upon sale or trade back to the manufacturers. If the Company does not receive proceeds of the contracted residual value from the manufacturer, the Company is still obligated to make the balloon payment at the end of the lease term. In connection with certain revenue equipment operating leases, the Company issues residual value guarantees, which provide that if the Company does not purchase the leased equipment from the lessor at the end of the lease term, then the Company is liable to the lessor for an amount equal to the shortage (if any) between the proceeds from the sale of the equipment and an agreed value. To the extent management believes any manufacturer will refuse or be unable to meet its obligation, the Company recognizes additional rental expense to the extent the fair market value at the lease termination is expected to be less than the obligation to the lessor. Proceeds from the sale of equipment under the Company’s operating leases generally exceed the payment obligation on substantially all operating leases. Although the Company typically owes certain amounts to its lessors at the end of its revenue equipment leases, the Company’s equipment manufacturers have corresponding guarantees back to the Company as to the buyback value of the units. Lease Cost — The components of the Company's lease cost were as follows: Quarter-to-Date June 30, 2019 Year-to-Date June 30, 2019 (in thousands) Operating lease cost $ 32,376 $ 67,194 Short-term lease cost ¹ 589 1,406 Sublease income (90 ) (180 ) Rental expense 32,875 68,420 Finance lease cost: Amortization of property and equipment 4,120 12,453 Interest expense 845 1,772 Total finance lease cost 4,965 14,225 Total operating and finance lease cost $ 37,840 $ 82,645 1 Short-term lease cost includes month-to-month and variable lease costs. Lease Liability Calculation Assumptions — The assumptions underlying the calculation of the Company's right-of-use assets and lease liabilities are disclosed below. June 30, 2019 Operating Finance Revenue equipment leases Weighted average remaining lease term 2.6 years 1.7 years Weighted average discount rate 2.6 % 3.8 % Real estate and other leases Weighted average remaining lease term 12.4 years 1.7 years Weighted average discount rate 4.2 % 2.0 % Maturity Analysis of Lease Liabilities (as Lessee) — Future minimum lease payments for all noncancelable leases were: June 30, 2019 Operating Finance (In thousands) Remainder of 2019 $ 57,858 $ 54,754 2020 81,449 15,828 2021 44,487 30,829 2022 26,643 18,528 2023 13,669 1,347 Thereafter 26,257 9,572 Future minimum lease payments 250,363 130,858 Less: amounts representing interest (21,779 ) (6,147 ) Present value of minimum lease payments 228,584 124,711 Less: current portion (98,904 ) (58,684 ) Lease liabilities, less current portion $ 129,680 $ 66,027 Supplemental Cash Flow Lease Disclosures — The following table sets forth cash paid for amounts included in the measurement of lease liabilities: Year-to-Date June 30, 2019 (in thousands) Operating cash flows from operating leases $ 65,995 Operating cash flows from finance leases 1,757 Financing cash flows from finance leases 36,941 Refer to Note 15 for information regarding the leasing transactions between the Company and related parties. Lessor Disclosures for Lease Accounting under ASC Topic 842 The Company's wholly-owned financing subsidiaries lease revenue equipment to the Company's independent contractors under operating leases, which generally have terms between three and four years, and include renewal and purchase options. These leases also include variable charges associated with miles driven in excess of the stipulated allowable miles in the contract, which are accounted for separately and presented in the table below. Lease classification is determined based on minimum rental receipts per the agreement, including residual value guarantees, when applicable, as well as receivables due to the Company upon default or cross-default. When independent contractors default on their leases, the Company typically re-leases the equipment to other independent contractors. As such, future lease receipts reflect original leases and re-leases. The owned assets underlying the Company's leases as lessor primarily consist of revenue equipment. As of June 30, 2019 , the gross carrying value of such revenue equipment underlying these leases was $99.0 million and accumulated depreciation was $31.0 million . Depreciation is calculated on a straight-line basis down to the residual value, as applicable, over the estimated useful life of the equipment. Depreciation expense for these assets was $3.9 million for the second quarter of 2019 and $7.7 million for year-to-date June 30, 2019 . Additionally, the Company periodically leases out real estate for use by third parties, some of which are subleases. These leases have varying terms, and may include renewal options. Management’s significant assumptions and judgments include the determination of the amount the Company expects to derive from the underlying asset at the end of the lease term, as well as whether a contract contains a lease. Lease Revenue and Rental Income — The components of the Company's lease revenue are included in "Revenue, excluding trucking fuel surcharge" and the Company's rental income is included in "Other income, net" in the condensed consolidated statements of comprehensive income. These amounts are disclosed in the table below. Quarter-to-Date June 30, 2019 Year-to-Date June 30, 2019 (in thousands) Operating lease revenue $ 11,078 $ 24,035 Variable lease revenue 599 1,110 Total lease revenue 1 $ 11,677 $ 25,145 Rental income 2 $ 2,499 $ 4,940 1 Primarily represents operating revenue earned by the Company's financing subsidiaries for leasing equipment to third-party independent contractors. 2 Represents non-operating income earned from leasing real estate to third parties. Maturity Analysis of Future Lease Revenues (as Lessor) — Future minimum lease revenues for all noncancelable leases were: June 30, 2019 (In thousands) Remainder of 2019 $ 29,903 2020 46,312 2021 31,547 2022 16,089 2023 4,692 Thereafter 1,943 Future minimum lease revenues $ 130,486 Refer to Note 15 for information regarding the leasing transactions between the Company and related parties. December 31, 2018 (ASC Topic 840 Disclosures) Note: The ASC Topic 840 Comparative Approach for adopting ASC Topic 842 requires companies to provide disclosures for all periods that continue to be in accordance with ASC Topic 840. Refer to Note 2 for more information regarding the Company's adoption methods and impact of adoption for ASC Topic 842. The Company finances a portion of its revenue equipment under capital and operating leases and certain terminals under operating leases. Capital Leases (as Lessee) — The Company's capital leases are typically structured with balloon payments at the end of the lease term equal to the residual value the Company is contracted to receive from certain equipment manufacturers upon sale or trade back to the manufacturers. If the Company does not receive proceeds of the contracted residual value from the manufacturer, the Company is still obligated to make the balloon payment at the end of the lease term. Certain leases contain renewal or fixed price purchase options. The present value of obligations under capital leases is included under "Capital lease obligations and long-term debt – current portion" and "Capital lease obligations – less current portion" in the condensed consolidated balance sheets. As of December 31, 2018 , the leases were collateralized by revenue equipment with a cost of $154.3 million and accumulated amortization of $34.2 million . Amortization of the equipment under capital leases is included in "Depreciation and amortization of property and equipment" in the Company's condensed consolidated statements of comprehensive income. Operating Leases (as Lessee) — Operating leases generally include tractors, trailers, chassis, and facilities. Substantially all lease agreements for revenue equipment have fixed payment terms based on the passage of time. The tractor lease agreements generally stipulate maximum miles and provide for mileage penalties for excess miles. These leases generally run for a period of three to five years for tractors and five to seven years for trailers. Operating and Capital Leases (as Lessee) — Annual future minimum lease payments for all noncancelable leases were: December 31, 2018 Operating Capital (In thousands) 2019 $ 123,380 $ 61,285 2020 79,088 15,843 2021 42,441 30,845 2022 24,693 18,528 2023 11,728 1,347 Thereafter 25,403 9,572 Future minimum lease payments $ 306,733 $ 137,420 Less: amounts representing interest (7,921 ) Present value of minimum lease payments 129,499 Less: current portion (58,251 ) Capital lease obligations – less current portion $ 71,248 Operating Leases (as Lessor) — The Company's wholly-owned financing subsidiaries lease revenue equipment to the Company's independent contractors under operating leases. Additionally, the Company periodically leases out facilities for use by third-parties. Annual future minimum lease payments receivable under operating leases for the periods noted below were: December 31, 2018 (In thousands) 2019 $ 54,080 2020 37,694 2021 22,991 2022 8,343 2023 13 Thereafter — Future minimum lease payments receivable $ 123,121 Lease classification is determined based on minimum rental payments per the agreement, including residual value guarantees, when applicable, as well as receivables due to the Company upon default or cross-default. When independent contractors default on their leases, the Company typically re-leases the equipment to other independent contractors. As such, future minimum lease payments reflect original leases and re-leases.

Accounts Receivable Securitizat

Accounts Receivable Securitization	6 Months Ended
	Jun. 30, 2019
Transfers and Servicing [Abstract]
Accounts Receivable Securitization	Accounts Receivable Securitization The 2018 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 condensed consolidated balance sheets. As of June 30, 2019 , the Company's eligible receivables generally have high credit quality, as determined by the obligor's corporate credit rating. The 2018 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 June 30, 2019 . 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 2018 RSA (dollars in thousands): 2018 RSA Effective date July 11, 2018 Final maturity date July 9, 2021 Borrowing capacity $325,000 Accordion option ¹ $175,000 Unused commitment fee rate ² 20 to 40 basis points Program fees on outstanding balances ³ one-month LIBOR + 80 to 100 basis points 1 The accordion option increases the maximum borrowing capacity, subject to participation of the purchasers. 2 The 2018 RSA commitment fee rate is based on the percentage of the maximum borrowing capacity utilized. 3 The 2018 RSA program fee is based on the Company's consolidated total net leverage ratio. Availability under the 2018 RSA is calculated as follows: June 30, December 31, (In thousands) Borrowing base, based on eligible receivables $ 284,700 $ 325,000 Less: outstanding borrowings ¹ (145,000 ) (240,000 ) Less: outstanding letters of credit (70,650 ) (70,900 ) Availability under accounts receivable securitization facilities $ 69,050 $ 14,100 1 Outstanding borrowings are included in "Accounts receivable securitization" in the condensed consolidated balance sheets, offset by $0.3 million of deferred loan costs. Interest accrued on the aggregate principal balance at a rate of 3.3% and 3.2% as of June 30, 2019 and December 31, 2018 , respectively. Program fees and unused commitment fees are recorded in "Interest expense" in the condensed consolidated statements of comprehensive income. The Company incurred accounts receivable securitization program fees of $1.9 million and $2.0 million during the quarter-to date June 30, 2019 and 2018 periods, respectively. The Company incurred accounts receivable securitization program fees of $3.9 million and $4.0 million during the year-to-date June 30, 2019 and 2018 periods, respectively. Refer to Note 17

Commitments

Commitments	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments	Commitments Purchase Commitments As of June 30, 2019 , the Company had outstanding commitments to purchase revenue equipment of $385.6 million in 2019 ( $340.1 million of which were tractor commitments) and none thereafter. These purchases may be financed through any combination of operating leases, finance leases, debt, proceeds from sales of existing equipment, and cash flows from operations. As of June 30, 2019 , the Company had outstanding commitments to purchase facilities and non-revenue equipment of $3.7 million in the remainder of 2019 , $1.1 million in 2020 through 2021, and none thereafter. Factors such as costs and opportunities for future terminal expansions may change the amount of such expenditures. TRP Commitments Since 2003, Knight has entered into partnership agreements with entities that make privately-negotiated equity investments, including Transportation Resource Partners, Transportation Resource Partners III, LP, TRP Capital Partners, LP, TRP CoInvest Partners, (NTI) I, LP, TRP CoInvest Partners, (QLS) I, LP, and TRP Coinvest Partners, FFR I, LP. In these agreements, Knight committed to invest in return for an ownership percentage. During the first quarter of 2019, Knight entered into and fulfilled a $5.0 million commitment to invest in TRP Coinvest FFR. There were no material changes related to the TRP commitments during the second quarter of 2019.

Contingencies and Legal Proceed

Contingencies and Legal Proceedings	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Contingencies and Legal Proceedings	Contingencies and Legal Proceedings Legal Proceedings Information is provided below regarding the nature, status, and contingent loss amounts, if any, associated with the Company's pending legal matters. 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. 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 $104.5 million , relating to the Company's outstanding legal proceedings as of June 30, 2019 . Based on management's present knowledge of the facts and (in certain cases) advice of outside counsel, management does not believe that loss contingencies arising from pending matters are likely to have a material adverse effect on the Company's overall financial position, operating results, or cash flows after taking into account any existing accruals. However, actual outcomes could be material to the Company's financial position, operating results, or cash flows for any particular period. EMPLOYEE COMPENSATION AND PAY PRACTICES MATTERS Washington Overtime Class Actions The plaintiffs allege one or more of the following, pertaining to Washington state-based driving associates: that Swift 1) failed to pay minimum wages; 2) failed to pay overtime; 3) failed to pay all wages due at established pay periods; 4) failed to provide proper meal and rest periods; 5) failed to provide accurate wage statements; and 6) unlawfully deducted from employee wages. The plaintiffs seek unpaid wages, exemplary damages, interest, other costs, and attorneys' fees. Plaintiff(s) Defendant(s) Date instituted Court or agency currently pending in Troy Slack ¹ Swift Transportation Company of Arizona, LLC and Swift Transportation Corporation September 9, 2011 United States District Court for the Western District of Washington Julie Hedglin ¹ Swift Transportation Company of Arizona, LLC and Swift Transportation Corporation January 14, 2016 United States District Court for the Western District of Washington Recent Developments and Current Status In February 2019, the court granted final approval of the Slack settlement. Additionally, in July 2019, the court granted final approval of the settlement in the Hedglin matter. The likelihood that a loss has been incurred for the Slack and Hedglin matters is probable and estimable, and the loss has accordingly been accrued. CRST Expedited Plaintiff alleges tortious interference with contract and unjust enrichment related to non-competition agreements entered into with certain of its drivers. Plaintiff(s) Defendant(s) Date instituted Court or agency currently pending in CRST Expedited, Inc. Swift Transportation Co. of Arizona LLC. March 20, 2017 United States District Court for the Northern District of Iowa Recent Developments and Current Status In July 2019, a jury issued an adverse verdict in this lawsuit. The Company is reviewing all options including post-trial motions seeking to overturn the jury verdict and if necessary, an appeal. The likelihood that a loss has been incurred is probable and estimable, and the loss has accordingly been accrued as of June 30, 2019. 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. The likelihood that a loss has been incurred is probable and estimable, and the loss has accordingly been accrued as of June 30, 2019. 1 Individually and on behalf of all others similarly situated. INDEPENDENT CONTRACTOR MATTERS Ninth Circuit Independent Contractor Misclassification Class Action The putative class alleges that Swift misclassified independent contractors as independent contractors, instead of employees, in violation of the FLSA and various state laws. The lawsuit also raises certain related issues with respect to the lease agreements that certain independent contractors have entered into with Interstate Equipment Leasing, LLC. The putative class seeks unpaid wages, liquidated damages, interest, other costs, and attorneys' fees. Plaintiff(s) Defendant(s) Date instituted Court or agency currently pending in Joseph Sheer, Virginia Van Dusen, Jose Motolinia, Vickii Schwalm, Peter Wood ¹ Swift Transportation Co., Inc., Interstate Equipment Leasing, Inc., Jerry Moyes, and Chad Killebrew December 22, 2009 Unites States District Court of Arizona and Ninth Circuit Court of Appeals Recent Developments and Current Status In April 2019, the court granted preliminary approval of the settlement in this matter. Based on the above, the likelihood that a loss has been incurred is probable and estimable, and the loss has accordingly been accrued as of June 30, 2019. 1 Individually and on behalf of all others similarly situated. Self Insurance The Company is insured against auto liability ("AL") claims under self-insured retention ("SIR") policies. Effective Novembe r 1, 2018, all AL claims provide for coverage up to $250.0 million per occurrence. Knight's AL claims have SIRs ranging from $1.0 million to $3.0 million per occurrence depending on the policy period with per occurrence limits of $130.0 million prior to November 1, 2018. Swift AL claims have $250.0 million of coverage per occurrence ( $350.0 million aggregated limits through October 31, 2016), subject to a $10.0 million SIR per occurrence. For the policy periods March 1, 2017 through February 28, 2020, the Knight SIR is $1.0 million with additional responsibility up to $1.6 million per occurrence within its primary limit and applicable aggregate limits. For the policy period March 1, 2016 to March 1, 2017, the Knight SIR was $2.5 million with no additional aggregate limits or deductibles within the primary AL policy. Knight also carries a $2.5 million aggregate deductible for any loss or losses within the excess coverage layer. The Company is self-insured for workers' compensation coverage. Swift maintains statutory coverage limits, subject to a $5.0 million SIR for each accident or disease. Effective March 1, 2019, Knight maintains statutory coverage limits, subject to a $2.0 million SIR for each accident or disease. Prior to March 1, 2019, the Knight SIR was $1.0 million per occurrence. Additionally, through Knight, the Company maintains primary and excess coverage for employee medical expenses and hospitalization, with self-insured retention of $0.3 million per claimant. Since January 1, 2015, Swift has been fully insured on its medical benefits, subject to contributed premiums.

Share Repurchase Plan

Share Repurchase Plan	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Share Repurchase Plan	Share Repurchase Plan On May 31, 2019, the Company announced that the Board approved the repurchase of up to $250.0 million worth of the Company's outstanding common stock (the "2019 Knight-Swift Share Repurchase Plan"). With the adoption of the 2019 Knight-Swift Share Repurchase Plan, the Company terminated the $250.0 million repurchase plan previously approved by the Board in June 2018 (the "2018 Knight-Swift Share Repurchase Plan"). There was approximately $0.2 million remaining under the 2018 Knight-Swift Share Repurchase Plan upon termination. The following table presents the Company's repurchases of its common stock under the respective share repurchase programs, net of advisory fees: Share Repurchase Plan Quarter-to-Date June 30, 2019 Year-to-Date June 30, 2019 Authorized Amount Board Approval Date Shares Amount Shares Amount (in thousands) (in thousands) $250,000 June 1, 2018 2,315 $ 70,500 2,315 $ 70,500 $250,000 May 30, 2019 559 16,392 559 16,392 2,874 $ 86,892 2,874 $ 86,892 No shares were purchased during the quarter or year-to-date periods ended June 30, 2018 . As of June 30, 2019 , $233.6 million remained available under the 2019 Knight-Swift Share Repurchase Plan. As of December 31, 2018 , $70.7 million remained available under the 2018 Knight-Swift Share Repurchase Plan.

Weighted Average Shares Outstan

Weighted Average Shares Outstanding	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Weighted Average Shares Outstanding	Weighted Average Shares Outstanding Basic and diluted earnings per share, 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-to-Date June 30, Year-to-Date June 30, 2019 2018 2019 2018 (In thousands) Basic weighted average common shares outstanding 172,078 178,451 172,522 178,307 Dilutive effect of equity awards 646 947 640 1,014 Diluted weighted average common shares outstanding 172,724 179,398 173,162 179,321 Anti-dilutive shares excluded from diluted earnings per share ¹ 916 47 933 57 1 Shares were excluded from the dilutive-effect calculation because the outstanding awards' exercise prices were greater than the average market price of Knight-Swift's common stock for the periods presented.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2019
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions The following table presents Knight-Swift's transactions with companies controlled by and/or affiliated with its related parties: Quarter-to-Date June 30, Year-to-Date June 30, 2019 2018 2019 2018 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) Freight Services: Central Freight Lines ¹ $ 3,843 $ — $ — $ — $ 6,959 $ — $ 427 $ — SME Industries ¹ 62 — 198 — 217 — 447 — Total $ 3,905 $ — $ 198 $ — $ 7,176 $ — $ 874 $ — Facility and Equipment Leases: Central Freight Lines ¹ $ 78 $ 92 $ 227 $ 93 $ 322 $ 185 $ 468 $ 185 Other Affiliates ¹ 5 — 5 — 9 — 11 — Total $ 83 $ 92 $ 232 $ 93 $ 331 $ 185 $ 479 $ 185 Other Services: Central Freight Lines ¹ $ 542 $ — $ — $ — $ 542 $ — $ — $ — Updike Distribution and Logistics ² 3 — 9 — 4 — 554 — Other Affiliates ¹ 9 668 9 751 18 1,330 18 1,354 Total $ 554 $ 668 $ 18 $ 751 $ 564 $ 1,330 $ 572 $ 1,354 1 Entities affiliated with former Board member Jerry Moyes include Central Freight Lines, SME Industries, Compensi Services, and DPF Mobile. Transactions with these entities that are controlled by and/or are otherwise affiliated with Jerry Moyes, include freight services, facility and equipment leases, equipment sales, and other services. • Freight Services Provided by Knight-Swift — The Company charges each of these companies for transportation services. • Freight Services Received by Knight-Swift — Transportation services received from Central Freight represent less-than-truckload freight services rendered to haul parts and equipment to Company shop locations. • Other Services Provided by Knight-Swift — Other services provided by the Company to the identified related parties include equipment sales and miscellaneous services. • Other Services Received by Knight-Swift — Consulting fees and certain third-party payroll and employee benefits administration services from the identified related parties are included in other services received by the Company. In conjunction with Swift's September 8, 2016 announcement that Jerry Moyes would retire from his position as Chief Executive Officer effective December 31, 2016, Swift entered into an agreement with Mr. Moyes to memorialize the terms of his retirement, which was assumed by Knight-Swift. Swift contracted with Mr. Moyes to serve as a non-employee consultant from January 1, 2017 through December 31, 2019, during which time Swift pays Mr. Moyes a monthly consulting fee in cash. The following is a rollforward of the accrued liability for the consulting fees: (In thousands) Accrued consulting fees – Jerry Moyes, balance at December 31, 2018 1a $ 2,225 Less: payments (1,025 ) Accrued consulting fees – Jerry Moyes, balance at June 30, 2019 1a $ 1,200 1a The balance is included in "Accrued liabilities" in the condensed consolidated balance sheet. 2 Knight had an arrangement with Updike Distribution and Logistics, a company that is owned by the father and three brothers of Executive Vice President of Sales and Marketing, James Updike, Jr. The arrangement allowed Updike Distribution and Logistics to purchase fuel from Knight's vendors at cost, plus an administrative fee. The arrangement was discontinued during the second quarter of 2018. Activities in the quarter and year-to-date periods ended June 30, 2019 pertain to sales of various spare parts and tractor accessories. Receivables and payables pertaining to related party transactions were: June 30, 2019 December 31, 2018 Receivable Payable Receivable Payable (In thousands) Central Freight Lines $ 2,960 $ — $ 254 $ — SME Industries 23 — 24 — Other Affiliates — 24 — 20 Total $ 2,983 $ 24 $ 278 $ 20

Information by Segment and Geog

Information by Segment and Geography	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Information by Segment and Geography	Information by Segment and Geography Segment Information As discussed in Note 1, the Company reorganized its reportable segments during the first quarter of 2019. Accordingly, the Company now has three reportable segments: Trucking, Logistics, and Intermodal, as well as the non-reportable segments, discussed below. Based on how economic factors affect the nature, amount, timing, and uncertainty of revenue or cash flows, the Company disaggregates revenues by reportable segment for the purposes of applying the ASC Topic 606 guidance. Trucking The Trucking segment is comprised of irregular route and dedicated dry van, refrigerated, expedited, flatbed, and cross-border operations. Abilene's trucking operations are also included after the March 16, 2018 acquisition date. Logistics The Logistics segment is primarily comprised of brokerage and other freight management services. Abilene's logistics operations are also included after the March 16, 2018 acquisition date. Intermodal The Intermodal segment includes revenue generated by moving freight over the rail in the Company's containers and other trailing equipment, combined with the Company's revenue for drayage to transport loads between the railheads and customer locations. Non-reportable The non-reportable segments include support services provided to the Company's customers and independent contractors (including repair and maintenance shop services, equipment leasing, warranty services, and insurance), trailer parts manufacturing, as well as certain corporate expenses (such as legal settlements and accruals and amortization of intangibles related to the 2017 Merger). Intersegment Eliminations Certain operating segments provide transportation and related services for other affiliates outside of their reportable segment. For certain operating segments, such services are billed at cost, and no profit is earned. For the other operating segments, revenues for such services are based on negotiated rates, and are reflected as revenues of the billing segment. These rates are adjusted from time to time, based on market conditions. Such intersegment revenues and expenses are eliminated in Knight-Swift's consolidated results. The following tables present the Company's financial information by segment: Quarter-to-Date June 30, Year-to-Date June 30, 2019 2018 (recast) 2019 2018 (recast) Revenue: (In thousands) Trucking $ 1,020,027 $ 1,081,832 $ 1,993,272 $ 2,119,196 Logistics 82,929 99,188 171,881 188,377 Intermodal 118,195 120,047 234,562 230,314 Subtotal $ 1,221,151 $ 1,301,067 $ 2,399,715 $ 2,537,887 Non-reportable segments 29,597 48,783 67,361 98,474 Intersegment eliminations (8,665 ) (18,167 ) (20,458 ) (33,546 ) Total revenue $ 1,242,083 $ 1,331,683 $ 2,446,618 $ 2,602,815 Quarter-to-Date June 30, Year-to-Date June 30, 2019 2018 (recast) 2019 2018 (recast) Operating income (loss): (In thousands) Trucking $ 125,772 $ 126,657 $ 240,947 $ 226,908 Logistics 5,021 4,615 12,304 8,574 Intermodal 4,192 4,480 6,553 8,428 Subtotal $ 134,985 $ 135,752 $ 259,804 $ 243,910 Non-reportable segments (26,392 ) (11,510 ) (34,912 ) (25,924 ) Operating income $ 108,593 $ 124,242 $ 224,892 $ 217,986 Quarter-to-Date June 30, Year-to-Date June 30, 2019 2018 (recast) 2019 2018 (recast) Depreciation and amortization of property and equipment: (In thousands) Trucking $ 86,842 $ 78,694 $ 171,352 $ 155,753 Logistics 159 137 314 261 Intermodal 3,303 2,945 6,663 5,718 Subtotal $ 90,304 $ 81,776 $ 178,329 $ 161,732 Non-reportable segments 12,634 13,972 25,546 27,879 Depreciation and amortization of property and equipment $ 102,938 $ 95,748 $ 203,875 $ 189,611 Geographical Information In the aggregate, total revenue from the Company's foreign operations was less than 5.0% of consolidated total revenue for the quarter and year-to-date periods ended June 30, 2019 and 2018 . Additionally, long-lived assets on the Company's foreign subsidiary balance sheets were less than 5.0% of consolidated total assets as of June 30, 2019 and December 31, 2018 .

Fair Value Measurement

Fair Value Measurement	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurement	Fair Value Measurement ASC Topic 820, Fair Value Measurements and Disclosures, requires that the Company disclose estimated fair values for its financial instruments. The estimated fair value of a financial instrument is the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date in the principal or most advantageous market for the asset or liability. Fair value estimates are made at a specific point in time and are based on relevant market information and information about the financial instrument. These estimates do not reflect any premium or discount that could result from offering for sale at one time the Company's entire holdings of a particular financial instrument. Changes in assumptions could significantly affect these estimates. Because the fair value is estimated as of June 30, 2019 and December 31, 2018 , the amounts that will actually be realized or paid at settlement or maturity of the instruments in the future could be significantly different. The estimated fair values of the Company's financial instruments as of June 30, 2019 and December 31, 2018 represent management's best estimates of the amounts that would be received to sell those assets or that would be paid to transfer those liabilities in an orderly transaction between market participants at that date. The estimated fair value measurements maximize the use of observable inputs. However, in situations where there is little, if any, market activity for the asset or liability at the measurement date, the estimated fair value measurement reflects management's own judgments about the assumptions that market participants would use in pricing the asset or liability. These judgments are developed by the Company based on the best information available under the circumstances. The following summary presents a description of the methods and assumptions used to estimate the fair value of each class of financial instrument. Restricted Investments, Held-to-Maturity — The estimated fair value of the Company's restricted investments, held-to-maturity, is based on quoted prices in active markets that are readily and regularly obtainable. See Note 5 for additional disclosures regarding restricted investments, held-to-maturity. Transportation Resource Partners — The estimated fair value of the Company's investments with Transportation Resource Partners are privately negotiated equity investments.The carrying amount of these investments approximates the fair value. Debt Instruments and Leases — For notes payable under the Revolver and the Term Loan, fair value approximates the carrying value due to the variable interest rate. The carrying value of the 2018 RSA approximates fair value, as the underlying receivables are short-term in nature and only eligible receivables (such as those with high credit ratings) are qualified to secure the borrowed amounts. For finance and operating leases, the carrying value approximates the fair value, as the Company's finance and operating leases are structured to amortize in a manner similar to the depreciation of the underlying assets. Other — Cash and cash equivalents, restricted cash, net accounts receivable, income tax refund receivable, and accounts payable represent financial instruments for which the carrying amount approximates fair value, as they are short-term in nature. These instruments are accordingly excluded from the disclosures below. All remaining balance sheet amounts excluded from the below are not considered financial instruments, subject to this disclosure. The following table presents the carrying amounts and estimated fair values of the Company's major categories of financial assets and liabilities: June 30, 2019 December 31, 2018 Carrying Estimated Carrying Estimated (In thousands) Financial Assets: Restricted investments, held-to-maturity ¹ $ 10,277 $ 10,283 $ 17,413 $ 17,398 TRP Investments ² 31,040 31,040 20,646 20,646 Financial Liabilities: Term Loan, due October 2020 ³ $ 364,707 $ 365,000 $ 364,590 $ 365,000 2018 RSA, due July 2021 4 144,684 145,000 239,606 240,000 Revolver, due October 2022 270,000 270,000 195,000 195,000 1 Refer to Note 5 for the differences between the carrying amounts and estimated fair values of the Company's restricted investments, held-to-maturity. 2 The investments are included in "Other long-term assets" on the condensed consolidated balance sheets. 3 The carrying amount of the Term Loan is included in "Long-term debt – less current portion," and is net of $0.3 million and $0.4 million in deferred loan costs as of June 30, 2019 and December 31, 2018 , respectively. 4 The carrying amount of the 2018 RSA is included in "Accounts receivable securitization," and is net of $0.3 million and $0.4 million in deferred loan costs as of June 30, 2019 and December 31, 2018 , respectively. Recurring Fair Value Measurements — As of June 30, 2019 and December 31, 2018 , there were no major categories of assets or liabilities on the condensed consolidated balance sheets estimated at fair value that were measured on a recurring basis. 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 June 30, 2019 and December 31, 2018 : Fair Value Measurements at Reporting Date Using: Estimated Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Losses (In thousands) As of June 30, 2019 Leasehold improvements ¹ $ — $ — $ — $ — $ (2,182 ) As of December 31, 2018 Software ² $ — $ — $ — $ — $ (550 ) Equipment ³ 2,800 — 2,800 — (2,248 ) 1 During the second quarter of 2019, the Company incurred an impairment of leasehold improvements related to the early termination of a lease on one of its operating properties. 2 During the fourth quarter of 2018, the Company incurred impairment charges related to replaced software systems. 3 During the fourth quarter of 2018, the Company identified a potential impairment when performing a cost analysis related to the operation of the Company's airplane. Once a potential impairment was identified, the Company performed a valuation using a market approach primarily based upon recent sales history of similar aircraft and industry publications (Level 2 inputs). The Company determined that the asset was impaired and incurred related charges of $2.2 million , which were allocated between the Trucking and Logistics segments based on each segment’s use of the asset. Nonrecurring Fair Value Measurements (Liabilities) — As of June 30, 2019 and December 31, 2018 , the Company had no major categories of liabilities estimated at fair value that were measured on a nonrecurring basis.

Introduction and Basis of Pre_2

Introduction and Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2019
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.

Leases (Policies)

Leases (Policies)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Lessee [Policy Text Block]	Management evaluates the Company’s leases based on the underlying asset groups. The assets currently underlying the Company’s leases include revenue equipment (primarily tractors and trailers), real estate (primarily buildings, office space, land, and drop yards), as well as technology and other equipment that supports business operations. Management’s significant assumptions and judgments include the determination of the discount rate (discussed below), as well as the determination of whether a contract contains a lease (specifically with respect to whether the Company's drop yard contracts contain identified assets). • Lease Term — The Company’s leases generally have lease terms corresponding to the useful lives of the underlying assets. Revenue equipment leases have fixed payment terms based on the passage of time, which is typically three to five years for tractors and five to seven years for trailers. Certain finance leases for revenue equipment contain renewal or fixed price purchase options. Real estate leases, excluding drop yards, generally have varying lease terms between five and fifteen years and may include renewal options. Drop yards include month-to-month leases, as well as leases with varying lease terms generally ranging from two to five years. Options to renew or purchase the underlying assets are considered in the determination of the right-of-use asset and lease liability once reasonably certain of exercise. • Portfolio Approach — The Company typically leases its revenue equipment under master lease agreements, which contain general terms, conditions, definitions, representations, warranties and other general language, while the specific contract provisions are contained within the various individual lease schedules that fall under a master lease agreement. Each individual leased asset within a lease schedule is similar in nature (i.e. all tractors or all trailers) and has identical contract provisions to all of the other individual leased assets within the same lease schedule (such as the contract provisions discussed above). Management has elected to apply the portfolio approach to its revenue equipment leases, as accounting for its revenue equipment under the portfolio approach would not be materially different from separately accounting for each individual underlying asset as a lease. Each individual real estate and other lease is accounted for at the individual asset level. • Nonlease components — Management has elected to combine its nonlease components (such as fixed charges for common area maintenance, real estate taxes, utilities, and insurance) with lease components for each class of underlying asset, as applicable, as the nonlease components in the Company’s lease contracts typically are not material. These nonlease components are usually present within the Company’s real estate leases. The Company’s assets are generally insured by umbrella policies, in which the premiums change from one policy period to the next, making them variable in nature. Accordingly, these insurance costs are excluded from the Company’s calculation of right-of-use assets and corresponding lease liabilities. • Short-term lease exemption — Management has elected to apply the short-term lease exemption to all asset groups. Accordingly, leases with terms of twelve months or less are not capitalized and continue to be expensed on a straight-line basis over the term of the lease. This primarily affects the Company’s drop yards and corresponding temporary structures on those drop yards. To a lesser extent, certain short-term leases for revenue equipment, technology, and other assets are affected. • Discount rate — The Company uses the rate implicit in the lease, when readily determinable. Otherwise the Company’s incremental borrowing rate is applied. Due to the unique structure of the Company’s revenue equipment leases, management believes that the rate implicit in the lease is readily determinable for such leases and the implicit rate is used. The Company’s use of the implicit rate (rather than the incremental borrowing rate) for its revenue equipment leases does not materially change the Company’s financial position or financial results either by financial statement caption or in total. The implicit interest rate is not readily determinable for the Company’s real estate and other leases. As such, management applies the Company’s incremental borrowing rate, which is defined by GAAP as the rate of interest that the Company would have to pay to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. The Company's incremental borrowing rate is based on the results of an independent third-party valuation. • Residual values — The Company's finance leases are typically structured with balloon payments at the end of the lease term equal to the residual value the Company is contracted to receive from certain equipment manufacturers upon sale or trade back to the manufacturers. If the Company does not receive proceeds of the contracted residual value from the manufacturer, the Company is still obligated to make the balloon payment at the end of the lease term. In connection with certain revenue equipment operating leases, the Company issues residual value guarantees, which provide that if the Company does not purchase the leased equipment from the lessor at the end of the lease term, then the Company is liable to the lessor for an amount equal to the shortage (if any) between the proceeds from the sale of the equipment and an agreed value. To the extent management believes any manufacturer will refuse or be unable to meet its obligation, the Company recognizes additional rental expense to the extent the fair market value at the lease termination is expected to be less than the obligation to the lessor. Proceeds from the sale of equipment under the Company’s operating leases generally exceed the payment obligation on substantially all operating leases. Although the Company typically owes certain amounts to its lessors at the end of its revenue equipment leases, the Company’s equipment manufacturers have corresponding guarantees back to the Company as to the buyback value of the units.
Lessor [Policy Text Block]	The Company's wholly-owned financing subsidiaries lease revenue equipment to the Company's independent contractors under operating leases, which generally have terms between three and four years, and include renewal and purchase options. These leases also include variable charges associated with miles driven in excess of the stipulated allowable miles in the contract, which are accounted for separately and presented in the table below. Lease classification is determined based on minimum rental receipts per the agreement, including residual value guarantees, when applicable, as well as receivables due to the Company upon default or cross-default. When independent contractors default on their leases, the Company typically re-leases the equipment to other independent contractors. As such, future lease receipts reflect original leases and re-leases. The owned assets underlying the Company's leases as lessor primarily consist of revenue equipment. As of June 30, 2019 , the gross carrying value of such revenue equipment underlying these leases was $99.0 million and accumulated depreciation was $31.0 million . Depreciation is calculated on a straight-line basis down to the residual value, as applicable, over the estimated useful life of the equipment. Depreciation expense for these assets was $3.9 million for the second quarter of 2019 and $7.7 million for year-to-date June 30, 2019 . Additionally, the Company periodically leases out real estate for use by third parties, some of which are subleases. These leases have varying terms, and may include renewal options.

Recently Adopted Accounting P_2

Recently Adopted Accounting Pronouncements (Tables)	6 Months Ended
	Jun. 30, 2019
Accounting Changes and Error Corrections [Abstract]
Recently Issued Accounting Pronouncements	Adoption Date Impact — The required disclosures regarding the adoption date impact of ASC Topic 842 on the condensed consolidated balance sheet are presented below. December 31, Opening Balance Adjustments January 1, (in thousands) Assets Prepaid expenses 2 $ 67,011 $ (948 ) $ 66,063 Operating lease right-of-use assets 1 — 280,527 280,527 Other long-term assets 2 51,721 (1 ) 51,720 Liabilities Accounts payable 2 $ 117,883 $ (437 ) $ 117,446 Accrued liabilities 2 151,500 (4,168 ) 147,332 Operating lease liabilities – current portion 1 — 119,963 119,963 Operating lease liabilities – less current portion 1 — 168,232 168,232 Deferred tax liabilities 3 739,538 — 739,538 Other long-term liabilities 2 23,294 (4,012 ) 19,282 1 These new line items on the condensed consolidated balance sheets represent the capitalization of the Company's operating leases as lessee. 2 The effect of adopting ASC Topic 842 reflects certain reclassifications to adjust the right-of-use assets. 3 Amounts are reflective of deferred tax impacts from capitalizing the Company's operating leases. Current Period Impact of Adoption — The required quantitative disclosures regarding the current period impact of adopting ASC Topic 842 on the condensed consolidated balance sheet are presented below. June 30, 2019 As Reported under ASC Topic 842 If Reported Under ASC Topic 840 Effect of Change to ASC Topic 842 (in thousands) Assets Prepaid expenses 2 $ 67,904 $ 68,334 $ (430 ) Gross property and equipment 4 3,546,930 3,513,658 33,272 Accumulated depreciation and amortization 4 (801,287 ) (800,165 ) (1,122 ) Operating lease right-of-use assets 1 221,026 — 221,026 Other long-term assets 2 59,850 59,851 (1 ) Liabilities Accounts payable 2 $ 165,085 $ 166,146 $ (1,061 ) Accrued liabilities 2 154,197 157,980 (3,783 ) Finance lease liabilities and long-term debt – current portion 4 58,684 26,531 32,153 Operating lease liabilities – current portion 1 98,904 — 98,904 Operating lease liabilities – less current portion 1 129,680 — 129,680 Deferred tax liabilities 3 749,077 749,136 (59 ) Other long-term liabilities 2 16,873 19,962 (3,089 ) 1 Refer to tabular footnote (1) under "Adoption Date Impact" above. 2 Refer to tabular footnote (2) under "Adoption Date Impact" above. 3 Refer to tabular footnote (3) under "Adoption Date Impact" above. 4 Amounts represent reclassification of operating lease liabilities to finance lease liabilities, as the Company became reasonably certain to purchase certain revenue equipment off of operating leases during the second quarter of 2019. Date Issued Reference Description Adoption Date and Method Financial Statement Impact July 2019 2019-07: Codification Updates to SEC Sections — Amendments to SEC Paragraphs Pursuant to SEC Final Rule Releases No. 33-10532, Disclosure Update and Simplification, and Nos. 33-10231 and 33-10442, Investment Company Reporting Modernization, and Miscellaneous Updates 1 The amendments in this ASU update several topics of the ASC to incorporate changes required by guidance made effective by SEC Final Rule Nos. 33-10532, 33-10231, and 33-10442. These final rules included extending the disclosure requirement of presenting changes in stockholders' equity for both current and comparative interim periods, changing the title of the income statement to statement of comprehensive income, and disclosing the dividend per share amount for each class of stock. July 2019, prospective adoption Presentation and disclosure impact only May 2019 2019-05: Financial Instruments —Credit Losses, Topic 326; Targeted Transition Relief 2 The amendments provide entities that hold instruments within the scope of Subtopic 326-20 with the option to irrevocably elect the fair value option in Subtopic 825-10. This fair value option election does not apply to instruments classified as held-to-maturity debt securities. January 2020, Adoption method varies by amendment Currently under evaluation, but not expected to be material April 2019 2019-04: Codification Improvements to Topic 326, Financial Instruments —Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments 2 The amendments address certain issues related to the implementation of ASU 2016-01 – Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, ASU 2016-13 – Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, and ASU 2017-12 – Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities. The amendments update the treatment of credit losses for accrued interest receivables and related recoveries, remove the prohibition of using projections of future interest rate environments when using a discounted cash flow method to measure expected credit losses, as well as outline other targeted improvements that clarify language and intent, better define scope and improve cross references, among others. The amendments in the ASU are effective for fiscal years beginning after December 15, 2019 and early adoption is permitted. January 2020, Adoption method varies by amendment Currently under evaluation, but not expected to be material Date Issued Reference Description Adoption Date and Method Financial Statement Impact March 2019 2019-01: Leases (Topic 842) – Codification Improvements 3 The amendments address certain issues related to the implementation of ASC Topic 842, including; determining the fair value of the underlying asset by lessors that are not manufacturers or dealers, presentation on the statement of cash flows for sales type and direct financing leases, and transition disclosures related to ASC Topic 250. The transition disclosures related to ASC Topic 250 clarify that entities are not required to disclose the impacts of adopting ASC Topic 842 on net income or related per share amounts in both interim and annual reporting periods. The amendments in this ASU are effective for fiscal years beginning after December 15, 2019. January 2019, Adoption method varies by amendment The Company will not disclose the impacts of adopting ASC Topic 842 on net income or related per share amounts. 1 The Company applied the relevant changes during the first quarter of 2019, in conjunction with the effective date per the final SEC rules. Given that the corresponding ASU was issued in July 2019, the amendments in the ASU will technically be adopted in the third quarter of 2019. 2 Not yet adopted. 3 Adopted during the first quarter of 2019.

Recently Issued Accounting Pr_2

Recently Issued Accounting Pronouncements (Tables)	6 Months Ended
	Jun. 30, 2019
Accounting Changes and Error Corrections [Abstract]
Recently Issued Accounting Pronouncements	Adoption Date Impact — The required disclosures regarding the adoption date impact of ASC Topic 842 on the condensed consolidated balance sheet are presented below. December 31, Opening Balance Adjustments January 1, (in thousands) Assets Prepaid expenses 2 $ 67,011 $ (948 ) $ 66,063 Operating lease right-of-use assets 1 — 280,527 280,527 Other long-term assets 2 51,721 (1 ) 51,720 Liabilities Accounts payable 2 $ 117,883 $ (437 ) $ 117,446 Accrued liabilities 2 151,500 (4,168 ) 147,332 Operating lease liabilities – current portion 1 — 119,963 119,963 Operating lease liabilities – less current portion 1 — 168,232 168,232 Deferred tax liabilities 3 739,538 — 739,538 Other long-term liabilities 2 23,294 (4,012 ) 19,282 1 These new line items on the condensed consolidated balance sheets represent the capitalization of the Company's operating leases as lessee. 2 The effect of adopting ASC Topic 842 reflects certain reclassifications to adjust the right-of-use assets. 3 Amounts are reflective of deferred tax impacts from capitalizing the Company's operating leases. Current Period Impact of Adoption — The required quantitative disclosures regarding the current period impact of adopting ASC Topic 842 on the condensed consolidated balance sheet are presented below. June 30, 2019 As Reported under ASC Topic 842 If Reported Under ASC Topic 840 Effect of Change to ASC Topic 842 (in thousands) Assets Prepaid expenses 2 $ 67,904 $ 68,334 $ (430 ) Gross property and equipment 4 3,546,930 3,513,658 33,272 Accumulated depreciation and amortization 4 (801,287 ) (800,165 ) (1,122 ) Operating lease right-of-use assets 1 221,026 — 221,026 Other long-term assets 2 59,850 59,851 (1 ) Liabilities Accounts payable 2 $ 165,085 $ 166,146 $ (1,061 ) Accrued liabilities 2 154,197 157,980 (3,783 ) Finance lease liabilities and long-term debt – current portion 4 58,684 26,531 32,153 Operating lease liabilities – current portion 1 98,904 — 98,904 Operating lease liabilities – less current portion 1 129,680 — 129,680 Deferred tax liabilities 3 749,077 749,136 (59 ) Other long-term liabilities 2 16,873 19,962 (3,089 ) 1 Refer to tabular footnote (1) under "Adoption Date Impact" above. 2 Refer to tabular footnote (2) under "Adoption Date Impact" above. 3 Refer to tabular footnote (3) under "Adoption Date Impact" above. 4 Amounts represent reclassification of operating lease liabilities to finance lease liabilities, as the Company became reasonably certain to purchase certain revenue equipment off of operating leases during the second quarter of 2019. Date Issued Reference Description Adoption Date and Method Financial Statement Impact July 2019 2019-07: Codification Updates to SEC Sections — Amendments to SEC Paragraphs Pursuant to SEC Final Rule Releases No. 33-10532, Disclosure Update and Simplification, and Nos. 33-10231 and 33-10442, Investment Company Reporting Modernization, and Miscellaneous Updates 1 The amendments in this ASU update several topics of the ASC to incorporate changes required by guidance made effective by SEC Final Rule Nos. 33-10532, 33-10231, and 33-10442. These final rules included extending the disclosure requirement of presenting changes in stockholders' equity for both current and comparative interim periods, changing the title of the income statement to statement of comprehensive income, and disclosing the dividend per share amount for each class of stock. July 2019, prospective adoption Presentation and disclosure impact only May 2019 2019-05: Financial Instruments —Credit Losses, Topic 326; Targeted Transition Relief 2 The amendments provide entities that hold instruments within the scope of Subtopic 326-20 with the option to irrevocably elect the fair value option in Subtopic 825-10. This fair value option election does not apply to instruments classified as held-to-maturity debt securities. January 2020, Adoption method varies by amendment Currently under evaluation, but not expected to be material April 2019 2019-04: Codification Improvements to Topic 326, Financial Instruments —Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments 2 The amendments address certain issues related to the implementation of ASU 2016-01 – Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, ASU 2016-13 – Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, and ASU 2017-12 – Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities. The amendments update the treatment of credit losses for accrued interest receivables and related recoveries, remove the prohibition of using projections of future interest rate environments when using a discounted cash flow method to measure expected credit losses, as well as outline other targeted improvements that clarify language and intent, better define scope and improve cross references, among others. The amendments in the ASU are effective for fiscal years beginning after December 15, 2019 and early adoption is permitted. January 2020, Adoption method varies by amendment Currently under evaluation, but not expected to be material Date Issued Reference Description Adoption Date and Method Financial Statement Impact March 2019 2019-01: Leases (Topic 842) – Codification Improvements 3 The amendments address certain issues related to the implementation of ASC Topic 842, including; determining the fair value of the underlying asset by lessors that are not manufacturers or dealers, presentation on the statement of cash flows for sales type and direct financing leases, and transition disclosures related to ASC Topic 250. The transition disclosures related to ASC Topic 250 clarify that entities are not required to disclose the impacts of adopting ASC Topic 842 on net income or related per share amounts in both interim and annual reporting periods. The amendments in this ASU are effective for fiscal years beginning after December 15, 2019. January 2019, Adoption method varies by amendment The Company will not disclose the impacts of adopting ASC Topic 842 on net income or related per share amounts. 1 The Company applied the relevant changes during the first quarter of 2019, in conjunction with the effective date per the final SEC rules. Given that the corresponding ASU was issued in July 2019, the amendments in the ASU will technically be adopted in the third quarter of 2019. 2 Not yet adopted. 3 Adopted during the first quarter of 2019.

Abilene Acquisition (Tables)

Abilene Acquisition (Tables)	6 Months Ended
	Jun. 30, 2019
Business Combinations [Abstract]
Summary of Pro Forma Revenue and Net Income	The following unaudited pro forma information combines the historical operations of Knight-Swift and Abilene giving effect to the Abilene Acquisition and related transactions as if they had been consummated on January 1, 2018, the beginning of the comparative periods presented. Year-to-Date June 30, 2018 (in thousands, except per share data) Total revenue $ 2,622,456 Net income attributable to Knight-Swift 162,222 Earnings per share – diluted 0.90

Restricted Investments, Held-_2

Restricted Investments, Held-to-Maturity (Tables)	6 Months Ended
	Jun. 30, 2019
Schedule of Investments [Abstract]
Schedule of Restricted Investments, Held-to-Maturity	The following tables present the cost or amortized cost, gross unrealized gains and temporary losses, and estimated fair value of the Company's restricted investments, held-to-maturity: June 30, 2019 Gross Unrealized Cost or Amortized Gains Temporary Estimated Fair Value (In thousands) US corporate securities $ 10,277 $ 6 $ — $ 10,283 Restricted investments, held-to-maturity $ 10,277 $ 6 $ — $ 10,283 December 31, 2018 Gross Unrealized Cost or Amortized Gains Temporary Estimated Fair Value (In thousands) US corporate securities $ 15,296 $ 1 $ (16 ) $ 15,281 Municipal bonds 1,082 — — 1,082 Negotiable certificate of deposits 1,035 — — 1,035 Restricted investments, held-to-maturity $ 17,413 $ 1 $ (16 ) $ 17,398

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The changes in the carrying amount of goodwill were as follows: (In thousands) Goodwill, balance at December 31, 2018 $ 2,919,176 Amortization relating to deferred tax assets (5 ) Abilene Acquisition ¹ 48 Goodwill, balance at June 30, 2019 $ 2,919,219 1
Schedule of Intangible Assets, net	Other intangible asset balances were as follows: June 30, December 31, (In thousands) Customer relationships and non-compete: Gross carrying amount $ 838,100 $ 838,100 Accumulated amortization (78,466 ) (57,081 ) Customer relationships and non-compete, net $ 759,634 $ 781,019 Trade names: Gross carrying amount 639,900 639,900 Intangible assets, net $ 1,399,534 $ 1,420,919

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Lease Cost	The components of the Company's lease cost were as follows: Quarter-to-Date June 30, 2019 Year-to-Date June 30, 2019 (in thousands) Operating lease cost $ 32,376 $ 67,194 Short-term lease cost ¹ 589 1,406 Sublease income (90 ) (180 ) Rental expense 32,875 68,420 Finance lease cost: Amortization of property and equipment 4,120 12,453 Interest expense 845 1,772 Total finance lease cost 4,965 14,225 Total operating and finance lease cost $ 37,840 $ 82,645 1 Short-term lease cost includes month-to-month and variable lease costs.
Lease Liability Calculation Assumptions	The assumptions underlying the calculation of the Company's right-of-use assets and lease liabilities are disclosed below. June 30, 2019 Operating Finance Revenue equipment leases Weighted average remaining lease term 2.6 years 1.7 years Weighted average discount rate 2.6 % 3.8 % Real estate and other leases Weighted average remaining lease term 12.4 years 1.7 years Weighted average discount rate 4.2 % 2.0 %
Maturity Analysis of Lease Liabilities (as Lessee)	Future minimum lease payments for all noncancelable leases were: June 30, 2019 Operating Finance (In thousands) Remainder of 2019 $ 57,858 $ 54,754 2020 81,449 15,828 2021 44,487 30,829 2022 26,643 18,528 2023 13,669 1,347 Thereafter 26,257 9,572 Future minimum lease payments 250,363 130,858 Less: amounts representing interest (21,779 ) (6,147 ) Present value of minimum lease payments 228,584 124,711 Less: current portion (98,904 ) (58,684 ) Lease liabilities, less current portion $ 129,680 $ 66,027
Supplemental Cash Flow (Leases)	The following table sets forth cash paid for amounts included in the measurement of lease liabilities: Year-to-Date June 30, 2019 (in thousands) Operating cash flows from operating leases $ 65,995 Operating cash flows from finance leases 1,757 Financing cash flows from finance leases 36,941
Lease Revenue and Rental Income	The components of the Company's lease revenue are included in "Revenue, excluding trucking fuel surcharge" and the Company's rental income is included in "Other income, net" in the condensed consolidated statements of comprehensive income. These amounts are disclosed in the table below. Quarter-to-Date June 30, 2019 Year-to-Date June 30, 2019 (in thousands) Operating lease revenue $ 11,078 $ 24,035 Variable lease revenue 599 1,110 Total lease revenue 1 $ 11,677 $ 25,145 Rental income 2 $ 2,499 $ 4,940 1 Primarily represents operating revenue earned by the Company's financing subsidiaries for leasing equipment to third-party independent contractors. 2 Represents non-operating income earned from leasing real estate to third parties.
Maturity Analysis of Lease Receivables (as Lessor)	Future minimum lease revenues for all noncancelable leases were: June 30, 2019 (In thousands) Remainder of 2019 $ 29,903 2020 46,312 2021 31,547 2022 16,089 2023 4,692 Thereafter 1,943 Future minimum lease revenues $ 130,486
Operating and Capital Leases (as Lessee)	Annual future minimum lease payments for all noncancelable leases were: December 31, 2018 Operating Capital (In thousands) 2019 $ 123,380 $ 61,285 2020 79,088 15,843 2021 42,441 30,845 2022 24,693 18,528 2023 11,728 1,347 Thereafter 25,403 9,572 Future minimum lease payments $ 306,733 $ 137,420 Less: amounts representing interest (7,921 ) Present value of minimum lease payments 129,499 Less: current portion (58,251 ) Capital lease obligations – less current portion $ 71,248
Operating Leases (as Lessor)	Annual future minimum lease payments receivable under operating leases for the periods noted below were: December 31, 2018 (In thousands) 2019 $ 54,080 2020 37,694 2021 22,991 2022 8,343 2023 13 Thereafter — Future minimum lease payments receivable $ 123,121

Accounts Receivable Securitiz_2

Accounts Receivable Securitization (Tables)	6 Months Ended
	Jun. 30, 2019
Transfers and Servicing [Abstract]
Schedule of Servicing Liabilities at Fair Value [Table Text Block]	The following table summarizes the key terms of the 2018 RSA (dollars in thousands): 2018 RSA Effective date July 11, 2018 Final maturity date July 9, 2021 Borrowing capacity $325,000 Accordion option ¹ $175,000 Unused commitment fee rate ² 20 to 40 basis points Program fees on outstanding balances ³ one-month LIBOR + 80 to 100 basis points 1 The accordion option increases the maximum borrowing capacity, subject to participation of the purchasers. 2 The 2018 RSA commitment fee rate is based on the percentage of the maximum borrowing capacity utilized. 3 The 2018 RSA program fee is based on the Company's consolidated total net leverage ratio. Availability under the 2018 RSA is calculated as follows: June 30, December 31, (In thousands) Borrowing base, based on eligible receivables $ 284,700 $ 325,000 Less: outstanding borrowings ¹ (145,000 ) (240,000 ) Less: outstanding letters of credit (70,650 ) (70,900 ) Availability under accounts receivable securitization facilities $ 69,050 $ 14,100 1 Outstanding borrowings are included in "Accounts receivable securitization" in the condensed consolidated balance sheets, offset by $0.3 million of deferred loan costs. Interest accrued on the aggregate principal balance at a rate of 3.3% and 3.2% as of June 30, 2019 and December 31, 2018 , respectively.

Contingencies and Legal Proce_2

Contingencies and Legal Proceedings (Tables)	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Schedule of Loss Contingencies by Contingency	EMPLOYEE COMPENSATION AND PAY PRACTICES MATTERS Washington Overtime Class Actions The plaintiffs allege one or more of the following, pertaining to Washington state-based driving associates: that Swift 1) failed to pay minimum wages; 2) failed to pay overtime; 3) failed to pay all wages due at established pay periods; 4) failed to provide proper meal and rest periods; 5) failed to provide accurate wage statements; and 6) unlawfully deducted from employee wages. The plaintiffs seek unpaid wages, exemplary damages, interest, other costs, and attorneys' fees. Plaintiff(s) Defendant(s) Date instituted Court or agency currently pending in Troy Slack ¹ Swift Transportation Company of Arizona, LLC and Swift Transportation Corporation September 9, 2011 United States District Court for the Western District of Washington Julie Hedglin ¹ Swift Transportation Company of Arizona, LLC and Swift Transportation Corporation January 14, 2016 United States District Court for the Western District of Washington Recent Developments and Current Status In February 2019, the court granted final approval of the Slack settlement. Additionally, in July 2019, the court granted final approval of the settlement in the Hedglin matter. The likelihood that a loss has been incurred for the Slack and Hedglin matters is probable and estimable, and the loss has accordingly been accrued. CRST Expedited Plaintiff alleges tortious interference with contract and unjust enrichment related to non-competition agreements entered into with certain of its drivers. Plaintiff(s) Defendant(s) Date instituted Court or agency currently pending in CRST Expedited, Inc. Swift Transportation Co. of Arizona LLC. March 20, 2017 United States District Court for the Northern District of Iowa Recent Developments and Current Status In July 2019, a jury issued an adverse verdict in this lawsuit. The Company is reviewing all options including post-trial motions seeking to overturn the jury verdict and if necessary, an appeal. The likelihood that a loss has been incurred is probable and estimable, and the loss has accordingly been accrued as of June 30, 2019. 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. The likelihood that a loss has been incurred is probable and estimable, and the loss has accordingly been accrued as of June 30, 2019. 1 Individually and on behalf of all others similarly situated. INDEPENDENT CONTRACTOR MATTERS Ninth Circuit Independent Contractor Misclassification Class Action The putative class alleges that Swift misclassified independent contractors as independent contractors, instead of employees, in violation of the FLSA and various state laws. The lawsuit also raises certain related issues with respect to the lease agreements that certain independent contractors have entered into with Interstate Equipment Leasing, LLC. The putative class seeks unpaid wages, liquidated damages, interest, other costs, and attorneys' fees. Plaintiff(s) Defendant(s) Date instituted Court or agency currently pending in Joseph Sheer, Virginia Van Dusen, Jose Motolinia, Vickii Schwalm, Peter Wood ¹ Swift Transportation Co., Inc., Interstate Equipment Leasing, Inc., Jerry Moyes, and Chad Killebrew December 22, 2009 Unites States District Court of Arizona and Ninth Circuit Court of Appeals Recent Developments and Current Status In April 2019, the court granted preliminary approval of the settlement in this matter. Based on the above, the likelihood that a loss has been incurred is probable and estimable, and the loss has accordingly been accrued as of June 30, 2019. 1 Individually and on behalf of all others similarly situated.

Share Repurchase Plan Share Rep

Share Repurchase Plan Share Repurchase Plan (Tables)	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Schedule of Share Repurchases	The following table presents the Company's repurchases of its common stock under the respective share repurchase programs, net of advisory fees: Share Repurchase Plan Quarter-to-Date June 30, 2019 Year-to-Date June 30, 2019 Authorized Amount Board Approval Date Shares Amount Shares Amount (in thousands) (in thousands) $250,000 June 1, 2018 2,315 $ 70,500 2,315 $ 70,500 $250,000 May 30, 2019 559 16,392 559 16,392 2,874 $ 86,892 2,874 $ 86,892

Weighted Average Shares Outst_2

Weighted Average Shares Outstanding (Tables)	6 Months Ended
	Jun. 30, 2019
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-to-Date June 30, Year-to-Date June 30, 2019 2018 2019 2018 (In thousands) Basic weighted average common shares outstanding 172,078 178,451 172,522 178,307 Dilutive effect of equity awards 646 947 640 1,014 Diluted weighted average common shares outstanding 172,724 179,398 173,162 179,321 Anti-dilutive shares excluded from diluted earnings per share ¹ 916 47 933 57 1 Shares were excluded from the dilutive-effect calculation because the outstanding awards' exercise prices were greater than the average market price of Knight-Swift's common stock for the periods presented.

Related Party Transactions (Tab

Related Party Transactions (Tables)	6 Months Ended
	Jun. 30, 2019
Related Party Transactions [Abstract]
Related Party Transactions	The following table presents Knight-Swift's transactions with companies controlled by and/or affiliated with its related parties: Quarter-to-Date June 30, Year-to-Date June 30, 2019 2018 2019 2018 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) Freight Services: Central Freight Lines ¹ $ 3,843 $ — $ — $ — $ 6,959 $ — $ 427 $ — SME Industries ¹ 62 — 198 — 217 — 447 — Total $ 3,905 $ — $ 198 $ — $ 7,176 $ — $ 874 $ — Facility and Equipment Leases: Central Freight Lines ¹ $ 78 $ 92 $ 227 $ 93 $ 322 $ 185 $ 468 $ 185 Other Affiliates ¹ 5 — 5 — 9 — 11 — Total $ 83 $ 92 $ 232 $ 93 $ 331 $ 185 $ 479 $ 185 Other Services: Central Freight Lines ¹ $ 542 $ — $ — $ — $ 542 $ — $ — $ — Updike Distribution and Logistics ² 3 — 9 — 4 — 554 — Other Affiliates ¹ 9 668 9 751 18 1,330 18 1,354 Total $ 554 $ 668 $ 18 $ 751 $ 564 $ 1,330 $ 572 $ 1,354 1 Entities affiliated with former Board member Jerry Moyes include Central Freight Lines, SME Industries, Compensi Services, and DPF Mobile. Transactions with these entities that are controlled by and/or are otherwise affiliated with Jerry Moyes, include freight services, facility and equipment leases, equipment sales, and other services. • Freight Services Provided by Knight-Swift — The Company charges each of these companies for transportation services. • Freight Services Received by Knight-Swift — Transportation services received from Central Freight represent less-than-truckload freight services rendered to haul parts and equipment to Company shop locations. • Other Services Provided by Knight-Swift — Other services provided by the Company to the identified related parties include equipment sales and miscellaneous services. • Other Services Received by Knight-Swift — Consulting fees and certain third-party payroll and employee benefits administration services from the identified related parties are included in other services received by the Company. In conjunction with Swift's September 8, 2016 announcement that Jerry Moyes would retire from his position as Chief Executive Officer effective December 31, 2016, Swift entered into an agreement with Mr. Moyes to memorialize the terms of his retirement, which was assumed by Knight-Swift. Swift contracted with Mr. Moyes to serve as a non-employee consultant from January 1, 2017 through December 31, 2019, during which time Swift pays Mr. Moyes a monthly consulting fee in cash. The following is a rollforward of the accrued liability for the consulting fees: (In thousands) Accrued consulting fees – Jerry Moyes, balance at December 31, 2018 1a $ 2,225 Less: payments (1,025 ) Accrued consulting fees – Jerry Moyes, balance at June 30, 2019 1a $ 1,200 1a The balance is included in "Accrued liabilities" in the condensed consolidated balance sheet. 2 Knight had an arrangement with Updike Distribution and Logistics, a company that is owned by the father and three brothers of Executive Vice President of Sales and Marketing, James Updike, Jr. The arrangement allowed Updike Distribution and Logistics to purchase fuel from Knight's vendors at cost, plus an administrative fee. The arrangement was discontinued during the second quarter of 2018. Activities in the quarter and year-to-date periods ended June 30, 2019 pertain to sales of various spare parts and tractor accessories. Receivables and payables pertaining to related party transactions were: June 30, 2019 December 31, 2018 Receivable Payable Receivable Payable (In thousands) Central Freight Lines $ 2,960 $ — $ 254 $ — SME Industries 23 — 24 — Other Affiliates — 24 — 20 Total $ 2,983 $ 24 $ 278 $ 20
Jerry Moyes consulting fees rollforward	The following is a rollforward of the accrued liability for the consulting fees: (In thousands) Accrued consulting fees – Jerry Moyes, balance at December 31, 2018 1a $ 2,225 Less: payments (1,025 ) Accrued consulting fees – Jerry Moyes, balance at June 30, 2019 1a $ 1,200 1a The balance is included in "Accrued liabilities" in the condensed consolidated balance sheet.

Information by Segment and Ge_2

Information by Segment and Geography (Tables)	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Summary Of Financial Information By Segments	The following tables present the Company's financial information by segment: Quarter-to-Date June 30, Year-to-Date June 30, 2019 2018 (recast) 2019 2018 (recast) Revenue: (In thousands) Trucking $ 1,020,027 $ 1,081,832 $ 1,993,272 $ 2,119,196 Logistics 82,929 99,188 171,881 188,377 Intermodal 118,195 120,047 234,562 230,314 Subtotal $ 1,221,151 $ 1,301,067 $ 2,399,715 $ 2,537,887 Non-reportable segments 29,597 48,783 67,361 98,474 Intersegment eliminations (8,665 ) (18,167 ) (20,458 ) (33,546 ) Total revenue $ 1,242,083 $ 1,331,683 $ 2,446,618 $ 2,602,815 Quarter-to-Date June 30, Year-to-Date June 30, 2019 2018 (recast) 2019 2018 (recast) Operating income (loss): (In thousands) Trucking $ 125,772 $ 126,657 $ 240,947 $ 226,908 Logistics 5,021 4,615 12,304 8,574 Intermodal 4,192 4,480 6,553 8,428 Subtotal $ 134,985 $ 135,752 $ 259,804 $ 243,910 Non-reportable segments (26,392 ) (11,510 ) (34,912 ) (25,924 ) Operating income $ 108,593 $ 124,242 $ 224,892 $ 217,986 Quarter-to-Date June 30, Year-to-Date June 30, 2019 2018 (recast) 2019 2018 (recast) Depreciation and amortization of property and equipment: (In thousands) Trucking $ 86,842 $ 78,694 $ 171,352 $ 155,753 Logistics 159 137 314 261 Intermodal 3,303 2,945 6,663 5,718 Subtotal $ 90,304 $ 81,776 $ 178,329 $ 161,732 Non-reportable segments 12,634 13,972 25,546 27,879 Depreciation and amortization of property and equipment $ 102,938 $ 95,748 $ 203,875 $ 189,611

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	6 Months Ended
	Jun. 30, 2019
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: June 30, 2019 December 31, 2018 Carrying Estimated Carrying Estimated (In thousands) Financial Assets: Restricted investments, held-to-maturity ¹ $ 10,277 $ 10,283 $ 17,413 $ 17,398 TRP Investments ² 31,040 31,040 20,646 20,646 Financial Liabilities: Term Loan, due October 2020 ³ $ 364,707 $ 365,000 $ 364,590 $ 365,000 2018 RSA, due July 2021 4 144,684 145,000 239,606 240,000 Revolver, due October 2022 270,000 270,000 195,000 195,000 1 Refer to Note 5 for the differences between the carrying amounts and estimated fair values of the Company's restricted investments, held-to-maturity. 2 The investments are included in "Other long-term assets" on the condensed consolidated balance sheets. 3 The carrying amount of the Term Loan is included in "Long-term debt – less current portion," and is net of $0.3 million and $0.4 million in deferred loan costs as of June 30, 2019 and December 31, 2018 , respectively. 4 The carrying amount of the 2018 RSA is included in "Accounts receivable securitization," and is net of $0.3 million and $0.4 million in deferred loan costs as of June 30, 2019 and December 31, 2018 , respectively.
Fair Value Measurements, Nonrecurring	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 June 30, 2019 and December 31, 2018 : Fair Value Measurements at Reporting Date Using: Estimated Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Losses (In thousands) As of June 30, 2019 Leasehold improvements ¹ $ — $ — $ — $ — $ (2,182 ) As of December 31, 2018 Software ² $ — $ — $ — $ — $ (550 ) Equipment ³ 2,800 — 2,800 — (2,248 ) 1 During the second quarter of 2019, the Company incurred an impairment of leasehold improvements related to the early termination of a lease on one of its operating properties. 2 During the fourth quarter of 2018, the Company incurred impairment charges related to replaced software systems. 3 During the fourth quarter of 2018, the Company identified a potential impairment when performing a cost analysis related to the operation of the Company's airplane. Once a potential impairment was identified, the Company performed a valuation using a market approach primarily based upon recent sales history of similar aircraft and industry publications (Level 2 inputs). The Company determined that the asset was impaired and incurred related charges of $2.2 million , which were allocated between the Trucking and Logistics segments based on each segment’s use of the asset.

Description of Business (Detail

Description of Business (Details)	6 Months Ended
	Jun. 30, 2019SegmentVehicle
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operational tractors in fleet	18,959
Number of company tractors	16,352
Number of independent contractor tractors	2,607
Number of trailers	56,902
Number of intermodal tractors	672
Number of intermodal containers	9,864
Number of reportable segments | Segment	3

Recently Adopted Accounting P_3

Recently Adopted Accounting Pronouncements Leases (ASC Topic 842): ASU 2016-02 — Leases (Details) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2019		Jan. 01, 2019		Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid expenses		$ 67,904	[1]	$ 66,063	[2]	$ 67,011	[2]
Gross property and equipment		3,546,930	[3]			3,305,944
Less: accumulated depreciation and amortization		(801,287)	[3]			(693,107)
Operating lease right-of-use assets		221,026	[4]	280,527	[5]	0	[5]
Other long-term assets		59,850	[1]	51,720	[2]	51,721	[2]
Accounts payable		165,085	[1]	117,446	[2]	117,883	[2]
Accrued liabilities		154,197	[1]	147,332	[2]	151,500	[2]
Finance lease liabilities and long-term debt – current portion		58,684	[3]			58,672
Operating lease liabilities – current portion		98,904	[4]	119,963	[5]	0	[5]
Operating lease liabilities – less current portion		129,680	[4]	168,232	[5]	0	[5]
Deferred tax liabilities		749,077	[6]	739,538	[7]	739,538	[7]
Other long-term liabilities		$ 16,873	[1]	$ 19,282	[2]	23,294	[2]
Lease, Practical Expedients, Package		true
Lease, Practical Expedient, Use of Hindsight		false
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid expenses	[2]					(948)
Operating lease right-of-use assets	[5]					280,527
Other long-term assets	[2]					(1)
Accounts payable	[2]					(437)
Accrued liabilities	[2]					(4,168)
Operating lease liabilities – current portion	[5]					119,963
Operating lease liabilities – less current portion	[5]					168,232
Deferred tax liabilities	[7]					0
Other long-term liabilities	[2]					$ (4,012)
Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid expenses	[1]	$ 68,334
Gross property and equipment	[3]	3,513,658
Less: accumulated depreciation and amortization	[3]	(800,165)
Operating lease right-of-use assets	[4]	0
Other long-term assets	[1]	59,851
Accounts payable	[1]	166,146
Accrued liabilities	[1]	157,980
Finance lease liabilities and long-term debt – current portion	[3]	26,531
Operating lease liabilities – current portion	[4]	0
Operating lease liabilities – less current portion	[4]	0
Deferred tax liabilities	[6]	749,136
Other long-term liabilities	[1]	19,962
Restatement Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid expenses	[1]	(430)
Gross property and equipment	[3]	33,272
Less: accumulated depreciation and amortization	[3]	(1,122)
Operating lease right-of-use assets	[4]	221,026
Other long-term assets	[1]	(1)
Accounts payable	[1]	(1,061)
Accrued liabilities	[1]	(3,783)
Finance lease liabilities and long-term debt – current portion	[3]	32,153
Operating lease liabilities – current portion	[4]	98,904
Operating lease liabilities – less current portion	[4]	129,680
Deferred tax liabilities	[6]	(59)
Other long-term liabilities	[1]	$ (3,089)
[1]	Refer to tabular footnote (2) under "Adoption Date Impact" above.
[2]	The effect of adopting ASC Topic 842 reflects certain reclassifications to adjust the right-of-use assets.
[3]	Amounts represent reclassification of operating lease liabilities to finance lease liabilities, as the Company became reasonably certain to purchase certain revenue equipment off of operating leases during the second quarter of 2019.
[4]	Refer to tabular footnote (1) under "Adoption Date Impact" above.
[5]	These new line items on the condensed consolidated balance sheets represent the capitalization of the Company's operating leases as lessee.
[6]	Refer to tabular footnote (3) under "Adoption Date Impact" above.
[7]	Amounts are reflective of deferred tax impacts from capitalizing the Company's operating leases

Recently Issued Accounting Pr_3

Recently Issued Accounting Pronouncements - (Details)	6 Months Ended
	Jun. 30, 2019
Accounting Standards Update 2019-07 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Description	The amendments in this ASU update several topics of the ASC to incorporate changes required by guidance made effective by SEC Final Rule Nos. 33-10532, 33-10231, and 33-10442. These final rules included extending the disclosure requirement of presenting changes in stockholders' equity for both current and comparative interim periods, changing the title of the income statement to statement of comprehensive income, and disclosing the dividend per share amount for each class of stock.
Adoption Method and Date	July 2019, prospective adoption	[1]
Financial Statement Impact	Presentation and disclosure impact only	[1]
Accounting Standards Update 2019-05 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Description	The amendments provide entities that hold instruments within the scope of Subtopic 326-20 with the option to irrevocably elect the fair value option in Subtopic 825-10. This fair value option election does not apply to instruments classified as held-to-maturity debt securities.	[2]
Adoption Method and Date	January 2020, Adoption method varies by amendment	[2]
Financial Statement Impact	Currently under evaluation, but not expected to be material	[2]
Accounting Standards Update 2019-04 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Description	The amendments address certain issues related to the implementation of ASU 2016-01 – Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, ASU 2016-13 – Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, and ASU 2017-12 – Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities. The amendments update the treatment of credit losses for accrued interest receivables and related recoveries, remove the prohibition of using projections of future interest rate environments when using a discounted cash flow method to measure expected credit losses, as well as outline other targeted improvements that clarify language and intent, better define scope and improve cross references, among others. The amendments in the ASU are effective for fiscal years beginning after December 15, 2019 and early adoption is permitted.	[2]
Adoption Method and Date	January 2020, Adoption method varies by amendment	[2]
Financial Statement Impact	Currently under evaluation, but not expected to be material	[2]
Accounting Standards Update 2019-01 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Description	The amendments address certain issues related to the implementation of ASC Topic 842, including; determining the fair value of the underlying asset by lessors that are not manufacturers or dealers, presentation on the statement of cash flows for sales type and direct financing leases, and transition disclosures related to ASC Topic 250. The transition disclosures related to ASC Topic 250 clarify that entities are not required to disclose the impacts of adopting ASC Topic 842 on net income or related per share amounts in both interim and annual reporting periods. The amendments in this ASU are effective for fiscal years beginning after December 15, 2019.	[3]
Adoption Method and Date	January 2019, Adoption method varies by amendment	[3]
Financial Statement Impact	The Company will not disclose the impacts of adopting ASC Topic 842 on net income or related per share amounts.	[3]
[1]	The Company applied the relevant changes during the first quarter of 2019, in conjunction with the effective date per the final SEC rules. Given that the corresponding ASU was issued in July 2019, the amendments in the ASU will technically be adopted in the third quarter of 2019.
[2]	Not yet adopted.
[3]	Adopted during the first quarter of 2019.

Abilene Acquisition - Consolida

Abilene Acquisition - Consolidated Pro Forma Financial Data (Details) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2018USD ($)$ / shares
Business Combinations [Abstract]
Total revenue	$ 2,622,456
Net income attributable to Knight-Swift	$ 162,222
Earnings per share – diluted | $ / shares	$ 0.90

Restricted Investments, Held-_3

Restricted Investments, Held-to-Maturity (Details) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019USD ($)Securities	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)Securities	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)Securities
Schedule of Investments [Line Items]
Cost or Amortized Cost	[1]	$ 10,277		$ 10,277		$ 17,413
Gross Unrealized Gains		6		6		1
Gross Unrealized Temporary Losses		0		0		(16)
Estimated Fair Value	[1]	$ 10,283		$ 10,283		$ 17,398
Securities with unrealized losses for less than 12 months | Securities		2		2		20
Impairment losses		$ 0	$ 0	$ 0	$ 0
United States corporate securities [Member]
Schedule of Investments [Line Items]
Cost or Amortized Cost		10,277		10,277		$ 15,296
Gross Unrealized Gains		6		6		1
Gross Unrealized Temporary Losses		0		0		(16)
Estimated Fair Value		$ 10,283		$ 10,283		15,281
Municipal bonds [Member]
Schedule of Investments [Line Items]
Cost or Amortized Cost						1,082
Gross Unrealized Gains						0
Gross Unrealized Temporary Losses						0
Estimated Fair Value						1,082
Negotiable certificate of deposits [Member]
Schedule of Investments [Line Items]
Cost or Amortized Cost						1,035
Gross Unrealized Gains						0
Gross Unrealized Temporary Losses						0
Estimated Fair Value						$ 1,035
Maximum [Member]
Schedule of Investments [Line Items]
Contractual maturities of fixed maturity securities				1 year
Duration of securities in unrealized loss position				12 months
[1]	Refer to Note 5 for the differences between the carrying amounts and estimated fair values of the Company's restricted investments, held-to-maturity.

Assets Held For Sale (Details)

Assets Held For Sale (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Long Lived Assets Held-for-sale [Line Items]
Period Assets are Expected To Be Sold			12 months
Gain on disposal of assets held for sale			$ 19,267	$ 15,812
Impairments	$ 2,182	$ 0	2,182	0
Equipment [Member]
Long Lived Assets Held-for-sale [Line Items]
Assets Held for Sale	43,500		43,500		$ 40,000
Gain on disposal of assets held for sale	7,500	9,100	19,200	16,600
Impairments	$ 0	$ 0	$ 0	$ 0

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets Summary of Changes in Carrying Amount of Goodwill (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Goodwill [Line Items]
Goodwill		$ 2,919,219		$ 2,919,219		$ 2,919,176
Amortization related to deferred tax assets				(5)
Abilene Acquisition	[1]			48
Goodwill impairments		$ 0	$ 0	0	$ 0
Trucking [Member]
Goodwill [Line Items]
Abilene Acquisition				$ 48
[1]	The goodwill associated with the Abilene Acquisition was allocated to the Trucking segment and was adjusted for equipment losses and claims incurred prior to the acquisition

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets Intangible Asset Balances (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Customer relationships and non-compete:
Gross carrying amount	$ 838,100	$ 838,100
Accumulated amortization	(78,466)	(57,081)
Customer relationships and non-compete, net	759,634	781,019
Trade names:
Gross carrying amount	639,900	639,900
Intangible assets, net	$ 1,399,534	$ 1,420,919

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets Narrative (Details) $ in Millions	Jun. 30, 2019USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense, remainder of year	$ 21.4
Amortization expense, 2020	42.7
Amortization expense, 2021	42.7
Amortization expense, 2022	42.6
Amortization Expense, 2023	$ 42.3

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Income Tax Contingency [Line Items]
Effective tax rate	24.70%	22.90%	24.40%	22.10%
Deferred Tax Assets, Valuation Allowance	$ 0		$ 0
Increase in Unrecognized Tax Benefits is Reasonably Possible	1		1
Decrease in unrecognized tax benefits, reasonably possible	1.7		1.7
Accrued interest and penalties	$ 1		$ 1		$ 1.4
Year subject to examination			2013
Minimum [Member]
Income Tax Contingency [Line Items]
Year under income tax examination			2013
Maximum [Member]
Income Tax Contingency [Line Items]
Year under income tax examination			2017

Lease Cost (Details)

Lease Cost (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Lease, Cost [Abstract]
Operating lease cost		$ 32,376		$ 67,194
Short-term lease cost ¹	[1]	589		1,406
Sublease income		(90)		(180)
Rental expense		32,875	$ 47,703	68,420	$ 100,578
Amortization of property and equipment		4,120		12,453
Interest expense		845		1,772
Total finance lease cost		4,965		14,225
Total operating and finance lease cost		$ 37,840		$ 82,645
[1]	Short-term lease cost includes month-to-month and variable lease costs.

Leases Lease Liability Calculat

Leases Lease Liability Calculation Assumptions (Details)	Jun. 30, 2019
Revenue Equipment [Member]
Property, Plant and Equipment [Line Items]
Operating Lease, Weighted Average Remaining Lease Term	2 years 7 months 6 days
Finance Lease, Weighted Average Remaining Lease Term	1 year 8 months 12 days
Operating Lease, Weighted Average Discount Rate, Percent	2.60%
Finance Lease, Weighted Average Discount Rate, Percent	3.80%
Land, Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Operating Lease, Weighted Average Remaining Lease Term	12 years 4 months 24 days
Finance Lease, Weighted Average Remaining Lease Term	1 year 8 months 12 days
Operating Lease, Weighted Average Discount Rate, Percent	4.20%
Finance Lease, Weighted Average Discount Rate, Percent	2.00%

Maturity Analysis of Lease Liab

Maturity Analysis of Lease Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019		Jan. 01, 2019	[2]	Dec. 31, 2018
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Remainder of 2019	$ 57,858
2020	81,449
2021	44,487
2022	26,643
2023	13,669
Thereafter	26,257
Future minimum lease payments	250,363
Less: amounts representing interest	(21,779)
Present value of minimum lease payments	228,584
Operating lease liabilities – current portion	(98,904)	[1]	$ (119,963)		$ 0	[2]
Operating lease liabilities – less current portion	129,680	[1]	$ 168,232		0	[2]
Finance Lease, Liability, Payment, Due [Abstract]
Remainder of 2019	54,754
2020	15,828
2021	30,829
2022	18,528
2023	1,347
Thereafter	9,572
Future minimum lease payments	130,858
Less: amounts representing interest	(6,147)
Present value of minimum lease payments	124,711
Finance lease liabilities and long-term debt – current portion	(58,684)	[3]			(58,672)
Finance lease liabilities – less current portion	$ 66,027				$ 71,248
[1]	Refer to tabular footnote (1) under "Adoption Date Impact" above.
[2]	These new line items on the condensed consolidated balance sheets represent the capitalization of the Company's operating leases as lessee.
[3]	Amounts represent reclassification of operating lease liabilities to finance lease liabilities, as the Company became reasonably certain to purchase certain revenue equipment off of operating leases during the second quarter of 2019.

Leases Supplemental Cash Flow (

Leases Supplemental Cash Flow (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019USD ($)
Leases [Abstract]
Operating cash flows for operating leases	$ 65,995
Operating cash flows for finance leases	1,757
Financing cash flows for finance leases	$ 36,941

Leases Operating Lease Revenue

Leases Operating Lease Revenue and Rental Income (Details) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2019		Jun. 30, 2018	Jun. 30, 2019		Jun. 30, 2018	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Gross property and equipment		$ 3,546,930	[1]		$ 3,546,930	[1]		$ 3,305,944
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment		801,287	[1]		801,287	[1]		$ 693,107
Depreciation and amortization of property and equipment		102,938		$ 95,748	203,875		$ 189,611
Operating Lease, Lease Income, Lease Payments		11,078			24,035
Variable lease revenue		599			1,110
Revenue Equipment [Member]
Property, Plant and Equipment [Line Items]
Gross property and equipment		99,000			99,000
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment		31,000			31,000
Depreciation and amortization of property and equipment		3,900			7,700
Total lease revenue	[2]	11,677			25,145
Land, Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Operating Lease, Lease Income, Lease Payments	[3]	$ 2,499			$ 4,940
[1]	Amounts represent reclassification of operating lease liabilities to finance lease liabilities, as the Company became reasonably certain to purchase certain revenue equipment off of operating leases during the second quarter of 2019.
[2]	Primarily represents operating revenue earned by the Company's financing subsidiaries for leasing equipment to third-party independent contractors.
[3]	Represents non-operating income earned from leasing real estate to third parties.

Leases Maturity Analysis of Fut

Leases Maturity Analysis of Future Lease Revenues (Details) $ in Thousands	Jun. 30, 2019USD ($)
Leases [Abstract]
Remainder of 2019	$ 29,903
2020	46,312
2021	31,547
2022	16,089
2023	4,692
Thereafter	1,943
Future minimum lease revenues	$ 130,486

Leases ASC Topic 840 Disclosure

Leases ASC Topic 840 Disclosures (Details) $ in Thousands	Dec. 31, 2018USD ($)
Leases [Abstract]
Capital Leases, Net Investment in Direct Financing Leases	$ 154,300
Accumulated Amortization	34,200
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019	123,380
2020	79,088
2021	42,441
2022	24,693
2023	11,728
Thereafter	25,403
Future minimum lease payments	306,733
Capital Leases, Future Minimum Payments, Net Present Value [Abstract]
2019	61,285
2020	15,843
2021	30,845
2022	18,528
2023	1,347
Thereafter	9,572
Future minimum lease payments	137,420
Less: amounts representing interest	(7,921)
Present value of minimum lease payments	129,499
Less: current portion	(58,251)
Finance lease liabilities – less current portion	71,248
Operating Leases, Future Minimum Payments Receivable [Abstract]
2019	54,080
2020	37,694
2021	22,991
2022	8,343
2023	13
Thereafter	0
Future minimum lease payments receivable	$ 123,121

Accounts Receivable Securitiz_3

Accounts Receivable Securitization (Details) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018	Jul. 11, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Servicing Liabilities at Fair Value [Line Items]
Program fees					$ 1,900	$ 2,000	$ 3,900	$ 4,000
2018 RSA [Member]
Servicing Liabilities at Fair Value [Line Items]
Effective date				Jul. 11, 2018
Final maturity date				Jul. 9, 2021
Receivables Sales Agreement, Borrowing Capacity				$ 325,000
Accordion Option Accounts Receivable Securitization	[1]			$ 175,000
Unused commitment fee rate	[2]			20 to 40 basis points
Program fees on outstanding balances	[3]			one-month LIBOR + 80 to 100 basis points
RSA Borrowing Base		$ 284,700	$ 325,000		284,700		284,700
Accounts receivable securitization	[4]	(145,000)	(240,000)		(145,000)		(145,000)
Letters of Credit Outstanding, Amount		(70,650)	(70,900)		(70,650)		(70,650)
Availability under accounts receivable securitization facilities		69,050	14,100		69,050		69,050
Deferred loan costs		$ 300	$ 400		$ 300		$ 300
Debt Instrument, Interest Rate During Period		3.30%	3.20%
[1]	The accordion option increases the maximum borrowing capacity, subject to participation of the purchasers.
[2]	The 2018 RSA commitment fee rate is based on the percentage of the maximum borrowing capacity utilized.
[3]	The 2018 RSA program fee is based on the Company's consolidated total net leverage ratio.
[4]	Outstanding borrowings are included in "Accounts receivable securitization" in the condensed consolidated balance sheets, offset by $0.3 million of deferred loan costs. Interest accrued on the aggregate principal balance at a rate of 3.3% and 3.2% as of June 30, 2019 and December 31, 2018 , respectively.

Commitments (Details)

Commitments (Details) - USD ($) $ in Millions	Jun. 30, 2019	Jan. 01, 2019
Capital Addition Purchase Commitments Total Revenue Equipment [Member]
Long-term Purchase Commitment [Line Items]
Purchase Obligation, Future Minimum Payments, Remainder of Fiscal Year	$ 385.6
Purchase Obligation, Due in Second and Third Year	0
Purchase Obligation, Due in Fourth Year	0
Purchase Obligation, Due in 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, Future Minimum Payments, Remainder of Fiscal Year	340.1
Capital Addition Purchase Commitments Non revenue equipment [Member]
Long-term Purchase Commitment [Line Items]
Purchase Obligation, Future Minimum Payments, Remainder of Fiscal Year	3.7
Purchase Obligation, Due in Second and Third Year	1.1
Purchase Obligation, Due in Fourth Year	0
Purchase Obligation, Due in Fifth Year	0
Purchase Obligation, Due after Fifth Year	0
Transportation Resource Partners, CoInvest Partners, FFR i [Member]
Long-term Purchase Commitment [Line Items]
Amounts Committed To Invest		$ 5
Remaining Investment Commitment	$ 0

Legal Proceedings (Details)

Legal Proceedings (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)
Commitments and Contingencies Disclosure [Abstract]
Loss contingency accrual	$ 104.5
Employee Compensation and Pay Practices Matters [Member] | Washington Overtime Class Action [Member]
Loss Contingencies [Line Items]
Loss contingency, allegations	The plaintiffs allege one or more of the following, pertaining to Washington state-based driving associates: that Swift 1) failed to pay minimum wages; 2) failed to pay overtime; 3) failed to pay all wages due at established pay periods; 4) failed to provide proper meal and rest periods; 5) failed to provide accurate wage statements; and 6) unlawfully deducted from employee wages. The plaintiffs seek unpaid wages, exemplary damages, interest, other costs, and attorneys' fees.
Loss contingency, opinion of counsel	In February 2019, the court granted final approval of the Slack settlement. Additionally, in July 2019, the court granted final approval of the settlement in the Hedglin matter. The likelihood that a loss has been incurred for the Slack and Hedglin matters is probable and estimable, and the loss has accordingly been accrued.
Employee Compensation and Pay Practices Matters [Member] | Washington Overtime Class Action [Member] | Washington Overtime Class Action 1 [Member]
Loss Contingencies [Line Items]
Loss contingency, name of plaintiffs	Troy Slack ¹	[1]
Loss contingency, name of defendant	Swift Transportation Company of Arizona, LLC and Swift Transportation Corporation
Lawsuit filing date	Sep. 9, 2011
Loss contingency, domicile of litigation	United States District Court for the Western District of Washington
Employee Compensation and Pay Practices Matters [Member] | Washington Overtime Class Action [Member] | Washington Overtime Class Action 2 [Member]
Loss Contingencies [Line Items]
Loss contingency, name of plaintiffs	Julie Hedglin ¹	[1]
Loss contingency, name of defendant	Swift Transportation Company of Arizona, LLC and Swift Transportation Corporation
Lawsuit filing date	Jan. 14, 2016
Loss contingency, domicile of litigation	United States District Court for the Western District of Washington
Employee Compensation and Pay Practices Matters [Member] | CRST Expedited [Member]
Loss Contingencies [Line Items]
Loss contingency, allegations	Plaintiff alleges tortious interference with contract and unjust enrichment related to non-competition agreements entered into with certain of its drivers.
Loss contingency, name of plaintiffs	CRST Expedited, Inc.
Loss contingency, name of defendant	Swift Transportation Co. of Arizona LLC.
Lawsuit filing date	Mar. 20, 2017
Loss contingency, domicile of litigation	United States District Court for the Northern District of Iowa
Loss contingency, opinion of counsel	In July 2019, a jury issued an adverse verdict in this lawsuit. The Company is reviewing all options including post-trial motions seeking to overturn the jury verdict and if necessary, an appeal. The likelihood that a loss has been incurred is probable and estimable, and the loss has accordingly been accrued as of June 30, 2019.
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. The likelihood that a loss has been incurred is probable and estimable, and the loss has accordingly been accrued as of June 30, 2019.
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
Loss contingency, name of defendant	Swift Transportation Co., Inc
Lawsuit filing date	Mar. 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
Loss contingency, name of defendant	Swift Transportation Co. of Arizona, LLC and Swift Transportation Company
Lawsuit filing date	Apr. 5, 2012
Loss contingency, domicile of litigation	United States District Court for the Central District of California
Independent Contractor Matters [Member] | Ninth circuit owner operator misclassification class action 1 [Member]
Loss Contingencies [Line Items]
Loss contingency, allegations	The putative class alleges that Swift misclassified independent contractors as independent contractors, instead of employees, in violation of the FLSA and various state laws. The lawsuit also raises certain related issues with respect to the lease agreements that certain independent contractors have entered into with Interstate Equipment Leasing, LLC. The putative class seeks unpaid wages, liquidated damages, interest, other costs, and attorneys' fees.
Loss contingency, name of plaintiffs	Joseph Sheer, Virginia Van Dusen, Jose Motolinia, Vickii Schwalm, Peter Wood ¹	[1]
Loss contingency, name of defendant	Swift Transportation Co., Inc., Interstate Equipment Leasing, Inc., Jerry Moyes, and Chad Killebrew
Lawsuit filing date	Dec. 22, 2009
Loss contingency, domicile of litigation	Unites States District Court of Arizona and Ninth Circuit Court of Appeals
Loss contingency, opinion of counsel	In April 2019, the court granted preliminary approval of the settlement in this matter. Based on the above, the likelihood that a loss has been incurred is probable and estimable, and the loss has accordingly been accrued as of June 30, 2019.
[1]	Individually and on behalf of all others similarly situated.

Contingencies and Legal Proce_3

Contingencies and Legal Proceedings Self Insurance (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)
Knight Transportation Company [Member]
Loss Contingencies [Line Items]
Insurance Aggregate Deductible Amount	$ 2.5
Self Insurance Retention Workers Compensation Claims Per Occurrence	1
Self Retention For Employee Medical Health	0.3
Knight Transportation Company [Member] | Minimum [Member]
Loss Contingencies [Line Items]
Self Insurance Retention	1
Knight Transportation Company [Member] | Maximum [Member]
Loss Contingencies [Line Items]
Self Insurance Retention	3
Swift Transportation Company [Member]
Loss Contingencies [Line Items]
Self Insurance Retention	10
Self Insurance Coverage Per Claim	250
Self Insurance Aggregate Coverage	350
Self Insurance Retention Workers Compensation Claims Per Occurrence	5
Policy Period, March 1 2019 to March 1, 2020 [Member]
Loss Contingencies [Line Items]
Self Insurance Coverage Per Claim	250
Policy Period, March 1 2019 to March 1, 2020 [Member] | Knight Transportation Company [Member]
Loss Contingencies [Line Items]
Self Insurance Retention Workers Compensation Claims Per Occurrence	2
Policy Period, March 1, 2018 to March 1, 2019 [Member] | Knight Transportation Company [Member]
Loss Contingencies [Line Items]
Self Insurance Retention	1
Excess Personal Injury And Property Damage Liability Insurance	130
Policy Period, March 1, 2018 to March 1, 2019 [Member] | Knight Transportation Company [Member] | Maximum [Member]
Loss Contingencies [Line Items]
Self Insurance Aggregate Losses	1.6
Policy Period, March 1, 2017 to March 1, 2018 [Member] | Knight Transportation Company [Member]
Loss Contingencies [Line Items]
Excess Personal Injury And Property Damage Liability Insurance	130
Policy Period, March 1, 2016 to March 1, 2017 [Member] | Knight Transportation Company [Member]
Loss Contingencies [Line Items]
Self Insurance Retention	2.5
Excess Personal Injury And Property Damage Liability Insurance	$ 130

Share Repurchase Plan (Details)

Share Repurchase Plan (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	May 30, 2019	Dec. 31, 2018	Jun. 01, 2018
Class of Stock [Line Items]
Share repurchase, shares	2,874		2,874
Share repurchase, value	$ 86,892		$ 86,892
Knight-Swift Share Repurchase Plan, May 31, 2019 [Member]
Class of Stock [Line Items]
Share repurchase plan, authorized amount, value					$ 250,000
Share repurchase plan, remaining authorized amount, value	$ 233,600		$ 233,600
Share repurchase, shares	559		559
Share repurchase, value	$ 16,392		$ 16,392
Knight-Swift Repurchase Plan, June 1, 2018 [Member]
Class of Stock [Line Items]
Share repurchase plan, authorized amount, value							$ 250,000
Share repurchase plan, remaining authorized amount, value					$ 200	$ 70,700
Share repurchase, shares	2,315	0	2,315	0
Share repurchase, value	$ 70,500	$ 0	$ 70,500	$ 0

Weighted Average Shares Outst_3

Weighted Average Shares Outstanding (Details) - shares shares in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Basic weighted average common shares outstanding		172,078	178,451	172,522	178,307
Dilutive effect of equity awards		646	947	640	1,014
Diluted weighted average common shares outstanding		172,724	179,398	173,162	179,321
Anti-dilutive shares excluded from diluted earnings per share	[1]	916	47	933	57
[1]	Shares were excluded from the dilutive-effect calculation because the outstanding awards' exercise prices were greater than the average market price of Knight-Swift's common stock for the periods presented.

Related Party Transactions (Sch

Related Party Transactions (Schedule Of Services Received and Provided By Company) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Related Party Transaction [Line Items]
Receivable		$ 2,983		$ 2,983		$ 278
Payable		24		24		20
Freight Services [Member]
Related Party Transaction [Line Items]
Provided by Knight-Swift		3,905	$ 198	7,176	$ 874
Received by Knight-Swift		0	0	0	0
Facility and Equipment Leases [Member]
Related Party Transaction [Line Items]
Provided by Knight-Swift		83	232	331	479
Received by Knight-Swift		92	93	185	185
Other Services [Member]
Related Party Transaction [Line Items]
Provided by Knight-Swift		554	18	564	572
Received by Knight-Swift		668	751	1,330	1,354
Central Freight Lines, Inc. [Member]
Related Party Transaction [Line Items]
Receivable		2,960		2,960		254
Payable		0		0		0
Central Freight Lines, Inc. [Member] | Freight Services [Member]
Related Party Transaction [Line Items]
Provided by Knight-Swift	[1]	3,843	0	6,959	427
Received by Knight-Swift	[1]	0	0	0	0
Central Freight Lines, Inc. [Member] | Facility and Equipment Leases [Member]
Related Party Transaction [Line Items]
Provided by Knight-Swift	[1]	78	227	322	468
Received by Knight-Swift	[1]	92	93	185	185
Central Freight Lines, Inc. [Member] | Other Services [Member]
Related Party Transaction [Line Items]
Provided by Knight-Swift	[1]	542	0	542	0
Received by Knight-Swift	[1]	0	0	0	0
SME Industries [Member]
Related Party Transaction [Line Items]
Receivable		23		23		24
Payable		0		0		0
SME Industries [Member] | Freight Services [Member]
Related Party Transaction [Line Items]
Provided by Knight-Swift	[1]	62	198	217	447
Received by Knight-Swift	[1]	0	0	0	0
Updike Distribution and Logistics [Member] | Other Services [Member]
Related Party Transaction [Line Items]
Provided by Knight-Swift	[2]	3	9	4	554
Received by Knight-Swift	[2]	0	0	0	0
Other Affiliates [Member]
Related Party Transaction [Line Items]
Receivable		0		0		0
Payable		24		24		$ 20
Other Affiliates [Member] | Facility and Equipment Leases [Member]
Related Party Transaction [Line Items]
Provided by Knight-Swift	[1]	5	5	9	11
Received by Knight-Swift	[1]	0	0	0	0
Other Affiliates [Member] | Other Services [Member]
Related Party Transaction [Line Items]
Provided by Knight-Swift	[1]	9	9	18	18
Received by Knight-Swift	[1]	$ 668	$ 751	$ 1,330	$ 1,354
[1]	Entities affiliated with former Board member Jerry Moyes include Central Freight Lines, SME Industries, Compensi Services, and DPF Mobile. Transactions with these entities that are controlled by and/or are otherwise affiliated with Jerry Moyes, include freight services, facility and equipment leases, equipment sales, and other services. • Freight Services Provided by Knight-Swift — The Company charges each of these companies for transportation services. • Freight Services Received by Knight-Swift — Transportation services received from Central Freight represent less-than-truckload freight services rendered to haul parts and equipment to Company shop locations. • Other Services Provided by Knight-Swift — Other services provided by the Company to the identified related parties include equipment sales and miscellaneous services. • Other Services Received by Knight-Swift — Consulting fees and certain third-party payroll and employee benefits administration services from the identified related parties are included in other services received by the Company. In conjunction with Swift's September 8, 2016 announcement that Jerry Moyes would retire from his position as Chief Executive Officer effective December 31, 2016, Swift entered into an agreement with Mr. Moyes to memorialize the terms of his retirement, which was assumed by Knight-Swift. Swift contracted with Mr. Moyes to serve as a non-employee consultant from January 1, 2017 through December 31, 2019, during which time Swift pays Mr. Moyes a monthly consulting fee in cash. The following is a rollforward of the accrued liability for the consulting fees: (In thousands) Accrued consulting fees – Jerry Moyes, balance at December 31, 2018 1a $ 2,225 Less: payments (1,025 ) Accrued consulting fees – Jerry Moyes, balance at June 30, 2019 1a $ 1,200 1a The balance is included in "Accrued liabilities" in the condensed consolidated balance sheet.
[2]	Knight had an arrangement with Updike Distribution and Logistics, a company that is owned by the father and three brothers of Executive Vice President of Sales and Marketing, James Updike, Jr. The arrangement allowed Updike Distribution and Logistics to purchase fuel from Knight's vendors at cost, plus an administrative fee. The arrangement was discontinued during the second quarter of 2018. Activities in the quarter and year-to-date periods ended June 30, 2019 pertain to sales of various spare parts and tractor accessories.

Related Party Transaction (Jerr

Related Party Transaction (Jerry Moyes' Retirement) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019USD ($)
Restructuring Reserve [Roll Forward]
Accrued consulting fees – Jerry Moyes, December 31, 2018	$ 2,225	[1]
Accrued consulting fees – Jerry Moyes, June 30, 2019	1,200	[1]
Payments for Restructuring	$ 1,025
[1]	The balance is included in "Accrued liabilities" in the condensed consolidated balance sheet.

Information by Segment and Ge_3

Information by Segment and Geography - Segment Financial Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)Segment	Jun. 30, 2018USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment			3
Total revenue	$ 1,242,083	$ 1,331,683	$ 2,446,618	$ 2,602,815
Operating income (loss)	108,593	124,242	224,892	217,986
Depreciation and amortization of property and equipment	102,938	95,748	203,875	189,611
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenue	1,221,151	1,301,067	2,399,715	2,537,887
Operating income (loss)	134,985	135,752	259,804	243,910
Depreciation and amortization of property and equipment	90,304	81,776	$ 178,329	161,732
Operating Segments [Member] | Trucking [Member]
Segment Reporting Information [Line Items]
Description of products and services			The Trucking segment is comprised of irregular route and dedicated dry van, refrigerated, expedited, flatbed, and cross-border operations. Abilene's trucking operations are also included after the March 16, 2018 acquisition date.
Total revenue	1,020,027	1,081,832	$ 1,993,272	2,119,196
Operating income (loss)	125,772	126,657	240,947	226,908
Depreciation and amortization of property and equipment	86,842	78,694	$ 171,352	155,753
Operating Segments [Member] | Logistics [Member]
Segment Reporting Information [Line Items]
Description of products and services			The Logistics segment is primarily comprised of brokerage and other freight management services. Abilene's logistics operations are also included after the March 16, 2018 acquisition date.
Total revenue	82,929	99,188	$ 171,881	188,377
Operating income (loss)	5,021	4,615	12,304	8,574
Depreciation and amortization of property and equipment	159	137	$ 314	261
Operating Segments [Member] | Intermodal [Member]
Segment Reporting Information [Line Items]
Description of products and services			The Intermodal segment includes revenue generated by moving freight over the rail in the Company's containers and other trailing equipment, combined with the Company's revenue for drayage to transport loads between the railheads and customer locations.
Total revenue	118,195	120,047	$ 234,562	230,314
Operating income (loss)	4,192	4,480	6,553	8,428
Depreciation and amortization of property and equipment	3,303	2,945	$ 6,663	5,718
Non-reportable segments [Member]
Segment Reporting Information [Line Items]
Description of all other segments			The non-reportable segments include support services provided to the Company's customers and independent contractors (including repair and maintenance shop services, equipment leasing, warranty services, and insurance), trailer parts manufacturing, as well as certain corporate expenses (such as legal settlements and accruals and amortization of intangibles related to the 2017 Merger).
Total revenue	29,597	48,783	$ 67,361	98,474
Operating income (loss)	(26,392)	(11,510)	(34,912)	(25,924)
Depreciation and amortization of property and equipment	12,634	13,972	25,546	27,879
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenue	$ (8,665)	$ (18,167)	$ (20,458)	$ (33,546)

Information by Segment and Ge_4

Information by Segment and Geography - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Segment Reporting [Abstract]
Percentages Of Foreign Operations Consolidated Revenue	5.00%	5.00%	5.00%	5.00%
Long lived assets of foreign operations	5.00%		5.00%		5.00%

Fair Value Measurement - Estima

Fair Value Measurement - Estimated Fair Values (Details) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Financial Assets:
Restricted investments, held-to-maturity, amortized cost	[1]	$ 10,277	$ 17,413
Estimated Fair Value	[1]	10,283	17,398
Transportation Resource Partner Investments (Carrying Value)	[2]	31,040	20,646
Transportation Resource Partner Investments (Estimated Fair Value)	[2]	31,040	20,646
Financial Liabilities:
Term loan, due October 2020, Carrying Value	[3]	364,707	364,590
Term loan, due October 2020, Fair Value	[3]	365,000	365,000
Accounts receivable securitization		144,684	239,606
Revolving line of credit		270,000	195,000
Loans Payable [Member]
Financial Liabilities:
Deferred loan costs		300	400
2018 RSA [Member]
Financial Liabilities:
Accounts receivable securitization	[4]	144,684	239,606
Debt Instrument, Fair Value Disclosure	[4]	145,000	240,000
Deferred loan costs		$ 300	$ 400
[1]	Refer to Note 5 for the differences between the carrying amounts and estimated fair values of the Company's restricted investments, held-to-maturity.
[2]	The investments are included in "Other long-term assets" on the condensed consolidated balance sheets.
[3]	The carrying amount of the Term Loan is included in "Long-term debt – less current portion," and is net of $0.3 million and $0.4 million in deferred loan costs as of June 30, 2019 and December 31, 2018 , respectively.
[4]	The carrying amount of the 2018 RSA is included in "Accounts receivable securitization," and is net of $0.3 million and $0.4 million in deferred loan costs as of June 30, 2019 and December 31, 2018

Fair Value Measurement - Recurr

Fair Value Measurement - Recurring and Nonrecurring Measurements (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended		12 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Losses, Software		$ 2,182	$ 0	$ 2,182	$ 0
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial and Nonfinancial Liabilities, Fair Value Disclosure						$ 0
Assets, Fair Value Disclosure		0		0
Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial and Nonfinancial Liabilities, Fair Value Disclosure		0		0		0
Leasehold Improvements [Member] | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Finite-lived Intangible Assets, Fair Value Disclosure	[1]	0		0
Impairment of Intangible Assets (Excluding Goodwill)	[1]	2,182
Leasehold Improvements [Member] | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Finite-lived Intangible Assets, Fair Value Disclosure	[1]	0		0
Leasehold Improvements [Member] | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Finite-lived Intangible Assets, Fair Value Disclosure	[1]	0		0
Leasehold Improvements [Member] | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Finite-lived Intangible Assets, Fair Value Disclosure	[1]	$ 0		$ 0
Software and Software Development Costs [Member] | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	[2]					0
Total Losses, Software	[2]					550
Software and Software Development Costs [Member] | 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	[2]					0
Software and Software Development Costs [Member] | 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	[2]					0
Software and Software Development Costs [Member] | 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	[2]					0
Equipment [Member] | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure	[3]					2,800
Total Losses, Equipment	[2],[3]					2,248
Equipment [Member] | 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	[3]					0
Equipment [Member] | 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	[3]					2,800
Equipment [Member] | 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	[3]					$ 0
[1]	During the second quarter of 2019, the Company incurred an impairment of leasehold improvements related to the early termination of a lease on one of its operating properties.
[2]	During the fourth quarter of 2018, the Company incurred impairment charges related to replaced software systems.
[3]	During the fourth quarter of 2018, the Company identified a potential impairment when performing a cost analysis related to the operation of the Company's airplane. Once a potential impairment was identified, the Company performed a valuation using a market approach primarily based upon recent sales history of similar aircraft and industry publications (Level 2 inputs). The Company determined that the asset was impaired and incurred related charges of $2.2 million , which were allocated between the Trucking and Logistics segments based on each segment’s use of the asset.