Knight-Swift Transportation (KNX) 10-Q 9 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Nov. 01, 2017
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Trading Symbol	KNX
Entity Registrant Name	Knight-Swift Transportation Holdings Inc.
Entity Central Index Key	1,492,691
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Common Class A [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		177,933,640
Common Class B [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		0

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents		$ 136,422	$ 8,021
Cash and cash equivalents - restricted		62,685	0
Restricted investments, held to maturity, amortized cost	[1]	22,303	0
Trade receivables, net of allowance for doubtful accounts of $15,811 and $2,727, respectively		545,588	133,846
Equipment sales receivables		709	8,321
Notes receivable, net		5,984	560
Prepaid expenses		65,004	13,244
Assets held for sale		24,891	9,634
Income tax receivable		39,850	8,406
Other current assets		24,419	8,159
Total current assets		927,855	190,191
Property and equipment:
Revenue equipment		2,050,343	910,042
Land and land improvements		216,509	54,106
Buildings and building improvements		357,357	145,866
Furniture and fixtures		40,093	20,241
Shop and service equipment		22,437	16,859
Leasehold improvements		9,529	4,735
Total property and equipment		2,696,268	1,151,849
Less: accumulated depreciation and amortization		(399,681)	(348,991)
Property and equipment, net		2,296,587	802,858
Notes receivable, long-term		12,659	3,047
Goodwill		2,989,270	47,031
Intangible assets, net		1,285,571	2,575
Other long-term assets, restricted cash and investments		35,866	32,823
Total assets		7,547,808	1,078,525
Current liabilities:
Accounts payable		198,168	18,006
Accrued payroll and purchased transportation		86,213	25,017
Accrued liabilities		213,313	16,722
Claims accruals – current portion		147,922	18,633
Long-term debt – current portion		30	0
Capital lease obligations – current portion		54,561	0
Dividend payable – current portion		299	272
Total current liabilities		700,506	78,650
Revolving line of credit		85,000	18,000
Long-term debt – less current portion		399,719	0
Capital lease obligations – less current portion		135,540	0
Accounts receivable securitization		285,000	0
Claims accruals – less current portion		204,203	13,290
Deferred tax liabilities		909,941	178,000
Long-term dividend payable and other long-term liabilities		29,643	1,854
Total liabilities		2,749,552	289,794
Commitments and contingencies (Note 18)
Stockholders’ equity:
Preferred stock, par value $0.01 per share; authorized 10,000; none issued		0	0
Additional paid-in capital		4,212,609	223,267
Retained earnings		581,382	562,404
Total Knight-Swift stockholders' equity		4,795,770	786,473
Noncontrolling interest		2,486	2,258
Total stockholders’ equity		4,798,256	788,731
Total liabilities and stockholders’ equity		7,547,808	1,078,525
Common Class A [Member]
Stockholders’ equity:
Common stock, value outstanding		1,779	802
Total stockholders’ equity		1,779	802
Common Class B [Member]
Stockholders’ equity:
Common stock, value outstanding		$ 0	$ 0
[1]	Restricted investments are included in "Restricted investments, held to maturity, amortized cost."

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Allowance for Doubtful Accounts Receivable, Current	$ 15,811	$ 2,727
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
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)	500,000,000	500,000,000
Common stock, shares issued (in shares)	177,880,000	80,229,000
Common stock, shares outstanding (in shares)	177,880,000	80,229,000
Common Class B [Member]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	250,000,000	250,000,000
Common stock, shares issued (in shares)	0	0

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenue:
Revenue, before fuel surcharge		$ 469,683	$ 256,243	$ 961,685	$ 763,684
Fuel surcharge		51,925	24,287	104,348	65,252
Total revenue		521,608	280,530	1,066,033	828,936
Operating expenses:
Salaries, wages and benefits		154,390	82,688	316,844	250,732
Fuel		62,300	34,616	131,252	94,815
Operations and maintenance		37,267	19,781	78,516	56,886
Insurance and claims		21,117	9,251	37,982	26,330
Operating taxes and licenses		8,793	4,546	17,839	14,645
Communications		1,921	976	4,125	3,224
Depreciation and amortization of property and equipment		43,477	29,004	102,280	86,111
Amortization of intangibles		2,654	125	2,904	375
Rental expense		15,388	1,279	17,939	3,724
Purchased transportation		127,434	57,069	244,358	168,772
Impairments		16,746	0	16,746	0
Miscellaneous operating expenses, net		11,972	4,261	21,873	9,580
Merger-related costs		12,338	0	16,516	0
Total operating expenses		515,797	243,596	1,009,174	715,194
Operating income		5,811	36,934	56,859	113,742
Other income (expense):
Interest income		370	83	559	259
Interest expense		(1,812)	(182)	(1,948)	(742)
Other (expense) income, net		(1,442)	1,389	(120)	4,602
Total other (expense) income		(2,884)	1,290	(1,509)	4,119
Income before income taxes		2,927	38,224	55,350	117,861
Income taxes (benefit) expense		(1,272)	14,141	17,786	45,095
Net income		4,199	24,083	37,564	72,766
Net income attributable to noncontrolling interest		(318)	(316)	(836)	(1,064)
Net income attributable to Knight-Swift	[1]	$ 3,881	$ 23,767	$ 36,728	$ 71,702
Earnings per share:
Basic (in dollars per share)		$ 0.04	$ 0.30	$ 0.42	$ 0.89
Diluted (in dollars per share)		0.04	0.29	0.41	0.88
Dividends declared per share: (in dollars per share)		$ 0.06	$ 0.06	$ 0.18	$ 0.18
Weighted average shares outstanding:
Basic (in shares)		102,846	80,040	87,978	80,284
Diluted (in shares)		103,752	80,949	88,847	81,112
[1]	early adopted ASU 2016-09, Improvements to Employee Share-Based Payment Accounting during the fourth quarter of 2016. The adoption of this standard resulted in the recognition of $1.8 million of excess tax benefits to the income tax provision for the year ended December 31, 2016. Net income and shares outstanding data for the quarter ended and year-to-date September 30, 2016 are presented as if the ASU was adopted at the beginning of 2016.

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income		$ 4,199	$ 24,083	$ 37,564	$ 72,766
Other comprehensive income, net of income taxes:
Realized gains from available-for-sale securities reclassified to net income (1)	[1]	0	(878)	0	(2,771)
Unrealized gain from changes in fair value of available-for-sale securities (2)	[2]	0	145	0	198
Other comprehensive income, net of income taxes:		0	(733)	0	(2,573)
Comprehensive income, net of income taxes		4,199	23,350	37,564	70,193
Comprehensive income attributable to noncontrolling interest		(318)	(316)	(836)	(1,064)
Comprehensive income attributable to Knight-Swift		$ 3,881	$ 23,034	$ 36,728	$ 69,129
[1]	Net of current income tax expense of $546 and $1,723 for the quarter ended and year-to-date September 30, 2016, respectively.
[2]	Net of deferred income tax expense of $85 and $104 for the quarter ended and year-to-date September 30, 2016, respectively.

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Realized gains from available-for-sale securities reclassified to net income, tax	$ 546	$ 1,723
Unrealized gain from changes in fair value of available-for-sale securities, tax	$ 85	$ 104

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Statement of Cash Flows [Abstract]
Net income	$ 37,564	$ 72,766
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property, equipment and intangibles	105,184	86,486
Amortization of debt issuance costs, and other	15	0
Gain on sale of equipment	(2,465)	(7,451)
Gain from available-for-sale securities	0	(4,494)
Impairments	16,746	0
Deferred income taxes	(9,467)	4,655
Provision for doubtful accounts and notes receivable	831	594
Non-cash compensation expense for issuance of common stock to certain members of the Board of Directors	398	398
Stock-based compensation expense	3,393	3,126
Income from investment in TRP partnerships	(1,660)	(177)
Transportation Resource Partners impairment	56	67
Increase (decrease) in cash resulting from changes in:
Trade receivables and equipment sales receivable	(6,027)	(133)
Other current assets	(215)	5,707
Prepaid expenses	(7,641)	649
Income tax receivable	(23,859)	33,122
Other long-term assets	126	547
Accounts payable	(4,447)	1,869
Accrued liabilities and claims accrual	23,791	(6,040)
Net cash provided by operating activities	132,323	191,691
Cash flows from investing activities:
Decrease (increase) in cash and cash equivalents – restricted	745	(19)
Proceeds from maturities of held-to-maturity investments	2,835	0
Purchases of held-to maturity investments	3,015	0
Proceeds from sale of available-for-sale securities	0	7,403
Proceeds from sale of property and equipment/assets held for sale	29,490	49,972
Purchases of property and equipment	(91,925)	(126,028)
Proceeds from notes receivable	1,826	1,348
Expenditures on assets held for sale	(720)	0
Payments received on equipment sale receivables	1,067	0
Cash payments to Transportation Resource Partners	(1,166)	(21,778)
Cash proceeds from Transportation Resource Partners	9,775	423
Cash and cash equivalents received with 2017 Merger	28,493	0
Net cash used in investing activities	(22,595)	(88,679)
Cash flows from financing activities:
Repayment of long-term debt and capital leases	(454,148)	0
Proceeds from long-term debt	400,000	0
Repayments on Knight Revolver, net	(18,000)	(60,000)
Borrowings on Revolver	85,000	0
Borrowings under accounts receivable securitization	20,000	0
Payment of deferred loan costs	(2,312)	0
Proceeds from exercise of stock options	9,726	9,321
Share withholding for taxes due on equity awards	(6,114)	(1,421)
Payments to repurchase company's common stock	0	(39,873)
Dividends paid	(14,769)	(14,753)
Cash distribution to noncontrolling interest holder	(710)	(1,091)
Net cash provided by (used) in financing activities	18,673	(107,817)
Net increase (decrease) in cash and cash equivalents	128,401	(4,805)
Cash and cash equivalents at beginning of period	8,021	8,691
Cash and cash equivalents at end of period	136,422	3,886
Cash paid during the period for:
Interest	2,924	782
Income taxes	50,709	7,238
Non-cash investing and financing transactions:
Equipment acquired included in accounts payable	16,557	6,436
Equipment sales receivables	954	0
Financing provided to independent contractors for equipment sold	1,801	1,024
Transfer from property and equipment to assets held for sale	26,180	25,035
Capital lease additions	15,020	0
Net dividend accrued for restricted stock units	$ 38	$ 69

Consolidated Statement Of Stock

Consolidated Statement Of Stockholders' Equity (Unaudited) - 9 months ended Sep. 30, 2017 - USD ($) $ 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, 2016							80,229,000
Beginning balance, value at Dec. 31, 2016	$ 788,731		$ 223,267	$ 562,404	$ 786,473	$ 2,258	$ 802
Increase (Decrease) in Stockholders' Equity [Roll Forward]
2017 Merger Reverse Split of Swift shares (in shares)	97,043,000
2017 Merger Reverse Split of Swift shares	$ 3,976,905		3,975,832		3,976,803	102	$ 971
Exercise of stock options and RSUs (in shares)							596,000
Exercise of stock options and RSUs	$ 9,726		9,720		9,726		$ 6
Issuance of common stock (in shares)	12,000
Issuance of common stock	$ 397		397		397
Shares withheld from RSU settlement	(3,215)			(3,215)	(3,215)
Employee stock-based compensation expense	3,393		3,393		3,393
Cash dividends paid and dividends accrued	(14,535)			(14,535)	(14,535)
Net income attributable to Knight-Swift	36,728	[1]		36,728	36,728
Other comprehensive income	0				0
Distribution to noncontrolling interest	(710)					(710)
Net income attributable to noncontrolling interest	836					836
Ending balance, shares at Sep. 30, 2017							177,880,000
Ending balance, value at Sep. 30, 2017	$ 4,798,256		$ 4,212,609	$ 581,382	$ 4,795,770	$ 2,486	$ 1,779
[1]	early adopted ASU 2016-09, Improvements to Employee Share-Based Payment Accounting during the fourth quarter of 2016. The adoption of this standard resulted in the recognition of $1.8 million of excess tax benefits to the income tax provision for the year ended December 31, 2016. Net income and shares outstanding data for the quarter ended and year-to-date September 30, 2016 are presented as if the ASU was adopted at the beginning of 2016.

Introduction and Basis of Prese

Introduction and Basis of Presentation	9 Months Ended
	Sep. 30, 2017
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 on Form 10-Q are specific to our company, commonly used in our industry, or are otherwise frequently used throughout our document. Definitions for these acronyms and terms are provided in the "Glossary of Terms," available in the front of this document. Merger On September 8, 2017, pursuant to the Agreement and Plan of Merger, dated as of April 9, 2017, by Swift Transportation Company, Bishop Merger Sub, Inc., a direct wholly owned subsidiary of Swift (“Merger Sub”), and Knight Transportation, Inc., Merger Sub merged with and into Knight, with Knight surviving as a direct wholly owned subsidiary of Swift (the “2017 Merger”). Immediately prior to the effective time of the 2017 Merger (the “Effective Time”), the certificate of incorporation of the Company was amended and restated (the “Amended Company Charter”) to reflect, among other things, that: (i) the Company’s corporate name changed from “Swift Transportation Company” to “Knight-Swift Transportation Holdings Inc.”; and (ii) each issued and outstanding share of Class B common stock, par value $0.01 per share, of Swift (the "Swift Class B Common Stock”) was converted (the “Class B Conversion”) into one share of Class A common stock, par value $0.01 per share, of Swift (the "Swift Class A Common Stock”) and immediately thereafter, each issued and outstanding share of Swift Class A Common Stock (including each share of Swift Class A Common Stock into which the shares Swift Class B Common Stock was converted pursuant to the Class B Conversion) was, by means of a reverse stock split (the “Reverse Split”), consolidated into 0.72 of a share of Class A Common Stock of the Company (the "Class A Common Stock"). No fractional shares of Class A Common Stock were issued in the Reverse Split, and, in connection with the Reverse Split, holders of Class A Common Stock became entitled to receive cash in lieu of any fractional shares in accordance with the Amended Company Charter. At the Effective Time, each share of common stock, par value $0.01 per share, of Knight (“Knight Common Stock”) issued and outstanding immediately prior to the Effective Time (other than shares held in the treasury of Knight or owned or held, directly or indirectly, by Swift or any wholly owned subsidiary of Swift or Knight, in each case not held in a fiduciary capacity on behalf of a third-party) was converted into the right to receive one share of Class A Common Stock. Upon the closing of the 2017 Merger, the shares of Knight Common Stock that previously traded under the ticker symbol “KNX” on the New York Stock Exchange (the “NYSE”) ceased trading on, and were delisted from, the NYSE. Shares of Class A Common Stock commenced trading on the NYSE, on a post-Reverse Split basis, under the ticker symbol “KNX” on September 11, 2017. For the year-to-date period ended September 30, 2017 , we recorded $16.5 million of direct and incremental costs associated with 2017 Merger-related activities, primarily incurred for legal and professional fees, which were recorded in the ”Merger-related costs” line in the accompanying condensed consolidated statements of income. In association with the 2017 Merger, we incurred merger-related bonuses and accelerated stock compensation expense totaling $5.6 million , which is recorded in the "Salaries, wages and benefits" line in the accompanying condensed consolidated statements of income. Additionally, we incurred $0.9 million in merger-related statutory filing fees and $0.1 million in driver-retention expenses recorded within the "Miscellaneous operating expenses" and "Purchased transportation" lines in the accompanying condensed consolidated statements of income. Description of Business Knight-Swift is a transportation solutions provider, headquartered in Phoenix, Arizona. As of September 30, 2017 , the Company's fleet of revenue equipment included 23,107 tractors (comprised of 18,099 company tractors and 5,008 independent contractor tractors), 75,715 trailers, and 9,122 intermodal containers. The Company’s six reportable segments are Knight Trucking, Knight Logistics, Swift Truckload, Swift Dedicated, Swift Refrigerated, and Swift Intermodal. 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 impeding operations. At the same time, operating expenses generally increase, and tractor productivity of our 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. During this period, the profitability of our operations is generally lower than during other parts of the year. Additionally, we have seen surges between Thanksgiving and Christmas resulting from holiday shopping trends toward delivery of gifts purchased over the Internet, as well as the impact of shorter holiday seasons. Basis of Presentation We accounted for the 2017 Merger using the acquisition method of accounting in accordance with Topic 805, Business Combinations . GAAP requires that either Knight or Swift is designated as the acquirer for accounting and financial reporting purposes (“Accounting Acquirer”). Based on the evidence available, Knight was designated as the Accounting Acquirer. In identifying Knight as the Accounting Acquirer, we took into account the structure of the 2017 Merger, the composition of the combined company’s board of directors and the designation of certain senior management positions of the combined company, among other factors. Accordingly, the historical financial statements of Knight are the historical financial statements of the combined company. As such, information included within our condensed consolidated (unaudited) statements of income, comprehensive income and cash flows and their respective footnotes include the results of Swift from and after September 8, 2017 (the date of the closing of the 2017 Merger) to September 30, 2017. See Note 5 for the description of the purchase price allocation. The condensed consolidated financial statements (unaudited) and footnotes included in this Quarterly Report on Form 10-Q should be read in conjunction with the consolidated financial statements and footnotes included in Knight's Annual Report on Form 10-K for the year ended December 31, 2016 . The condensed consolidated financial statements (unaudited) include the accounts of Knight-Swift Transportation Holdings Inc. and its subsidiaries. In management's opinion, these condensed consolidated financial statements (unaudited) were prepared in accordance with GAAP and include all adjustments necessary (consisting of normal recurring adjustments) for the fair presentation of the periods presented. Changes in Presentation Recently Adopted Accounting Pronouncement — During the fourth quarter of 2016, Knight early adopted Accounting Standards Update No. 2016-09, Compensation - Stock Compensation (Topic 718): Improvement to Employee Share-Based Payment Accounting (ASU 2016-09). The standard requires us to reflect any adoption adjustments as of the beginning of the annual period that includes the interim period of adoption. As such, our condensed consolidated statements of income, statements of comprehensive income and statements of cash flows for the quarter ended and year-to-date September 30, 2016 , have been recast to include the impact of ASU 2016-09 adoption. See "Note 1-Significant Accounting Policies" in the notes to Knight's consolidated financial statements in Knight's Annual Report on Form 10-K for the fiscal year ended December 31, 2016 for detailed adoption information. Other Presentation Changes — Beginning in 2017 , we made the following changes in presentation: • Equipment sales receivables are separately presented within "Total current assets" in the condensed consolidated unaudited balance sheets. The prior period presentation has been retrospectively adjusted to reclassify the amount out of "Trade receivables, net of allowance for doubtful accounts" and into the new line item "Equipment sales receivable." The change in presentation has no net impact on "Total current assets." • Rental expenses related to revenue equipment are separately presented within "Total operating expenses" in the condensed consolidated statements of income. The prior period presentation has been retrospectively adjusted to reclassify the amount out of "Miscellaneous operating expenses" and into the new line item "Rental expense." The change in presentation has no impact on "Total operating expenses." • Excess tax benefits within the condensed consolidated statement of cash flows should be classified along with other income tax cash flows as an operating activity. Application is permitted to be prospective or retrospective. GAAP previously required classification within cash flows from financing activities. We retrospectively adjusted the year-to-date September 30, 2016 condensed consolidated statement of cash flows to align with the current period presentation by increasing cash flows from operating activities by $1.1 million and correspondingly decreasing cash flows from financing activities by $1.1 million , reflecting the amount of excess tax benefits previously presented for that period. Summary of Significant Accounting Policies In association with the 2017 Merger, we have the following additional significant accounting policies not previously disclosed within Knight's consolidated financial statements and footnotes included in Knight's Annual Report on Form 10-K for the year ended December 31, 2016 . Restricted Cash — Our wholly-owned captive insurance companies, Red Rock and Mohave, maintain certain operating bank accounts, working trust accounts, and investment accounts. The cash and short-term investments within the accounts are restricted by insurance regulations to fund the insurance claim losses to be paid by the captive insurance companies. Therefore, these cash and short-term investments are classified as "Cash and cash equivalents - restricted" in the condensed consolidated balance sheets. Restricted Investments -— Our investments are restricted by insurance regulations to fund the insurance claim losses to be paid by the captive insurance companies. The Company accounts for its investments in accordance with ASC 320, Investments - Debt and Equity Securities . Management determines the appropriate classification of its investments in debt securities at the time of purchase and re-evaluates the determination on a quarterly basis. As of September 30, 2017, all of our investments in fixed-maturity securities were classified as held-to-maturity, as we have the positive intent and ability to hold these securities to maturity. Held-to-maturity securities are carried at amortized cost. The amortized cost of debt securities is adjusted using the effective interest rate method for amortization of premiums and accretion of discounts. Amortization and accretion are reported in "Other income, net" in the condensed consolidated statement of income (unaudited). Management periodically evaluates restricted investments for impairment. The assessment of whether impairments have occurred is based on management's case-by-case evaluation of the underlying reasons for the decline in estimated fair value. Management accounts for other-than-temporary impairments of debt securities in accordance with ASC 320, Investments - Debt and Equity Securities . This guidance requires the Company to evaluate whether it intends to sell an impaired debt security or whether it is more likely than not that it will be required to sell an impaired debt security before recovery of the amortized cost basis. If either of these criteria are met, an impairment loss equal to the difference between the debt security's amortized cost and its estimated fair value is recognized in earnings. For impaired debt securities that do not meet these criteria, we determine if a credit loss exists with respect to the impaired security. If a credit loss exists, the credit loss component of the impairment (i.e., the difference between the security's amortized cost and the present value of projected future cash flows expected to be collected) is recognized in earnings and the remaining portion of the impairment is recognized as a component of accumulated other comprehensive income. Operating Leases — In accordance with ASC 840, Leases , property and equipment held under operating leases, and liabilities related thereto, are off-balance sheet. All expenses related to operating leases are reflected in our condensed consolidated statements of income (unaudited) in "Rental expense." At the inception of a lease, management judgment is involved in classification as an operating or capital lease, as well as determination of useful lives and estimation of residual values of the related equipment. Future minimum lease payments used in determining lease classification represent the minimum rental payments called for over the lease term, inclusive of residual value guarantees (if applicable) and amounts that would be required to be paid, if any, by the Company upon default for leases containing subjective acceleration or cross default clauses. We do not currently guarantee residual values under our operating lease agreements for revenue equipment. To the extent we believe any manufacturer will refuse or be unable to meet its obligation, we recognize additional rental expense to the extent we believe the fair market value at the lease termination will be less than our obligation to the lessor. We believe that proceeds from the sale of equipment under operating leases would exceed the payment obligation on substantially all operating leases.

Recently Issued Accounting Pron

Recently Issued Accounting Pronouncements, Not Yet Adopted	9 Months Ended
	Sep. 30, 2017
Accounting Changes and Error Corrections [Abstract]
Recently Issued Accounting Pronouncements, Not Yet Adopted	Recently Issued Accounting Pronouncements, Not Yet Adopted Date Issued Reference Description Expected Adoption Date and Method Financial Statement Impact January 2017 2014-04: Intangibles – Goodwill and Other (Topic 350) – Simplifying the Test for Goodwill Impairment This update simplifies how an entity is required to test goodwill for impairment. Under the new guidance, annual or interim goodwill impairment testing will be performed by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment loss for the amount by which the carrying amount exceeds the reporting unit’s fair value. Any impairment loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. January 2020 Currently under evaluation November 2016 2016-18: Statement of Cash Flows (Topic 230) – Restricted Cash This update requires companies to include amounts generally described as restricted cash and restricted cash equivalents in cash and cash equivalents when reconciling beginning-of-period and end-of-period total amounts shown on the statement of cash flows. January 2018 Currently under evaluation August 2016 2016-15: Statement of Cash Flows (Topic 203) – Classification of Certain Cash Receipts and Cash Payments This update addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice. January 2018 Currently under evaluation May 2016 2016-12: Revenue from Contracts with Customers (Topic 606) – Narrow-scope Improvements and Practical Expedients The amendments in this ASU clarify certain aspects regarding the collectibility criterion, sales taxes collected from customers, noncash consideration, contract modifications, and completed contracts at transition. It additionally clarifies that retrospective application only requires disclosure of the accounting change effect on prior periods presented, not on the period of adoption. January 2018, Modified retrospective Currently under evaluation (1) April 2016 2016-10: Revenue from Contracts with Customers (Topic 606) – Identifying Performance Obligations and Licensing The amendments in this ASU clarify the following two aspects of Topic 606: identifying performance obligations and the licensing implementation guidance, while retaining the related principles for those areas. The amendments do not change the core principle of the guidance. January 2018, Modified retrospective Currently under evaluation (1) March 2016 2016-08: Revenue from Contracts with Customers (Topic 606) – Principal versus Agent Considerations (Reporting Revenue Gross versus Net) The amendments in this ASU are intended to improve the operability and understandability of the implementation guidance on principal versus agent considerations, but do not change the core principle of the guidance. January 2018, Modified retrospective Currently under evaluation (1) Date Issued Reference Description Expected Adoption Date and Method Financial Statement Impact February 2016 2016-02: Leases (Topic 842) This update seeks to increase the transparency and comparability among entities by requiring public entities to recognize lease assets and lease liabilities on the balance sheet and disclose key information about leasing arrangements. To satisfy the standard’s objective, a lessee will recognize a right-of-use asset representing its right to use the underlying asset for the lease term and a lease liability for the obligation to make lease payments. Both the right-of-use asset and lease liability will initially be measured at the present value of the lease payments, with subsequent measurement dependent on the classification of the lease as either a finance or an operating lease. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. If a lessee makes this election, it should recognize lease expense for such leases generally on a straight-line basis over the lease term. Accounting by lessors will remain mostly unchanged from current GAAP. January 2019, Modified retrospective Currently under evaluation; expected to be material, but not yet quantifiable. January 2016 2016-01: Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities The update (i) requires equity investments (except those accounted for under the equity method or that are consolidated) to be measured at fair value with changes in fair value recognized in net income; (ii) simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; (iii) eliminates the requirement for an entity to disclose the methods and significant assumptions used to estimate the fair value of financial instruments measured at amortized cost; (iv) requires an entity to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; and (v) requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or in the accompanying notes to the financial statements. January 2018, retrospective Currently under evaluation August 2015 2015-14: Revenue from Contracts with Customers (Topic 606) – Deferral of the Effective Date This ASU deferred the effective date of ASU 2014-09 (Topic 606) to annual reporting periods beginning after December 15, 2017. January 2018, Modified retrospective Currently under evaluation (1) ____________ (1) We have established an ASC 606 implementation team, which includes support from external experts, to evaluate and implement the standard. The diagnostic phase of assessing the financial and business impacts of implementing the standard is well underway and includes identifying revenue sources within the our lines of business, reviewing a sample of contracts, analyzing the impact on our systems, and developing a preliminary assessment. Based upon the procedures performed in the diagnostic phase, we anticipates that the following key considerations will impact the our accounting and reporting under the new standard: • identification of what constitutes a contract in the our business practices, • variability in individual contracts, such as customer-specific terms that may vary from the master agreement, • principal versus agent determinations, • timing of revenue recognition (for example, point-in-time versus over time and/or accelerated versus deferred), • single versus multiple performance obligations, including the timing of when such performance obligations are satisfied • new/changed estimates and management judgments (for example, system estimation of in-transit accruals versus manual estimation), • disaggregation of revenue by category within segments, and • others. We expect that there will also be changes in sales, contracting, accounting, reporting, tax, debt covenants, and other business processes, policies, and controls, as a result of implementing the standard. The 2017 Merger is also affecting the timing and other components of the implementation process. Based on the information currently available from the diagnostic phase, we cannot yet determine the quantitative impact on the financial statements. We expect changes related to the timing of revenue recognition between reportable periods, as well as changes in the requirements for accounting policy and other new disclosures. As the diagnostic phase is being finalized, we are proceeding to design and develop solutions in preparation for the implementation phase of the standard. Since we are continuing to evaluate the impact of the standard, disclosures around these preliminary assessments are subject to change.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The following table reconciles the basic and diluted earnings per share computation for the quarter ended and year-to-date September 30, 2017 and 2016 : Quarter Ended September 30, Year-to-Date September 30, 2017 2016 2017 2016 (In thousands, except per share data) Weighted-average common shares outstanding – basic 102,846 80,040 87,978 80,284 Dilutive effect of stock options and unvested restricted stock units (1) 906 909 869 828 Weighted-average common shares outstanding – diluted 103,752 80,949 88,847 81,112 Net income attributable to Knight-Swift (2) $ 3,881 $ 23,767 $ 36,728 $ 71,702 Basic earnings per share $ 0.04 $ 0.30 $ 0.42 $ 0.89 Diluted earnings per share $ 0.04 $ 0.29 $ 0.41 $ 0.88 ____________ (1) Shares were excluded from the dilutive-effect calculation because the outstanding options' exercise prices were greater than the average market price of Knight's Common Stock for the 2016 periods and the Class A Common Stock for the 2017 periods. Quarter Ended September 30, Year-to-Date September 30, 2017 2016 2017 2016 (In thousands) Number of anti-dilutive shares 654 937 488 1,072 (2) Knight early adopted ASU 2016-09, Improvements to Employee Share-Based Payment Accounting during the fourth quarter of 2016. The adoption of this standard resulted in the recognition of $1.8 million of excess tax benefits to the income tax provision for the year ended December 31, 2016. Net income and shares outstanding data for the quarter ended and year-to-date September 30, 2016 are presented as if the ASU was adopted at the beginning of 2016.

Information by Segment and Geog

Information by Segment and Geography	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Information by Segment and Geography	Information by Segment and Geography Segment Information As a result of the 2017 Merger, we have six reportable segments, which are the historical reportable operating segments of Knight and Swift: Knight Trucking, Knight Logistics, Swift Truckload, Swift Dedicated, Swift Refrigerated and Swift Intermodal. In determining our reportable segments, we focus on financial information such as total revenue and expenses, operating income, operating ratios, and other key operating statistics common in the industry. Our chief operating decision makers also use this information to evaluate this information to evaluate segment performance and allocate resources to our operations. Knight Segments: Knight Trucking — The Knight Trucking segment is comprised of three operating units (Dry Van, Refrigerated and Drayage). Knight Logistics — The Knight Logistics segment is comprised of two operating units (Brokerage and Intermodal). We also provide logistics freight management and other non-trucking services through our Knight Logistics business. Swift Segments: Swift Truckload — The Swift Truckload segment consists of one-way movements over irregular routes throughout the United States, Mexico, and Canada. Swift Dedicated — The Swift Dedicated segment devotes use of equipment to specific customers and offers tailored solutions under long-term contracts. Swift Refrigerated — The Swift Refrigerated segment primarily consists of shipments for customers that require temperature-controlled trailers. These shipments include one-way movements over irregular routes, as well as dedicated truck operations. Swift Intermodal — The Swift Intermodal segment includes revenue generated by moving freight over the rail in Swift's containers and other trailing equipment, combined with revenue for drayage to transport loads between the railheads and customer locations. Swift Non-reportable Segments — The Swift non-reportable segments include Swift's logistics and freight brokerage services, as well as support services that Swift's subsidiaries provide to customers and independent contractors, including repair and maintenance shop services, equipment leasing and insurance. Certain legal settlements and reserves, and other corporate expenses are also included in the non-reportable segments. Intersegment Eliminations — Certain operating segments provide transportation and related services for other affiliates outside their reportable segment. For Knight operating segments, such services are billed at cost, and no profit is earned. For Swift 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 our consolidated results. The following tables present our financial information by segment: Quarter Ended September 30, Year-to-Date September 30, 2017 2016 2017 2016 Amount % of Total Amount % of Total Amount % of Total Amount % of Total Total revenue: (Dollars in thousands) Knight Trucking $ 222,307 42.6 % $ 228,590 81.5 % $ 661,320 62.0 % $ 672,969 81.2 % Logistics 57,904 11.1 53,643 19.1 166,959 15.7 163,955 19.8 Swift Truckload 115,899 22.2 — — 115,899 10.9 — — Dedicated 39,120 7.5 — — 39,120 3.7 — — Refrigerated 47,506 9.1 — — 47,506 4.5 — — Intermodal 24,046 4.6 — — 24,046 2.3 — — Subtotal 506,782 282,233 1,054,850 836,924 Swift Non-reportable segments 20,212 3.9 — — 20,212 1.9 — — Intersegment (5,386 ) (1.0 ) (1,703 ) (0.6 ) (9,029 ) (1.0 ) (7,988 ) (1.0 ) Consolidated $ 521,608 100.0 % $ 280,530 100.0 % $ 1,066,033 100.0 % $ 828,936 100.0 % Quarter Ended September 30, Year-to-Date September 30, 2017 2016 2017 2016 Amount % of Total Amount % of Total Amount % of Total Amount % of Total Operating income (loss): (Dollars in thousands) Knight Trucking $ 8,581 147.7 % $ 34,439 93.2 % $ 54,603 96.0 % $ 105,647 92.9 % Logistics 3,651 62.8 2,495 6.8 8,677 15.3 8,095 7.1 Swift Truckload 7,967 137.1 — — 7,967 14.0 — — Dedicated 2,949 50.7 — — 2,949 5.2 — — Refrigerated 427 7.3 — — 427 0.8 — — Intermodal 1,396 24.0 — — 1,396 2.5 — — Subtotal 24,971 36,934 76,019 113,742 Swift Non-reportable segments (19,160 ) (329.6 ) — — (19,160 ) (33.8 ) — — Consolidated operating income $ 5,811 100.0 % $ 36,934 100.0 % $ 56,859 100.0 % $ 113,742 100.0 % Quarter Ended September 30, Year-to-Date September 30, 2017 2016 2017 2016 Amount % of Total Amount % of Total Amount % of Total Amount % of Total Depreciation and amortization of property and equipment (Dollars in thousands) Knight Trucking $ 27,552 63.4 % $ 27,863 96.1 % $ 83,678 81.8 % $ 82,999 96.4 % Logistics 1,245 2.9 1,141 3.9 3,922 3.8 3,112 3.6 Swift Truckload 6,179 14.2 — — 6,179 6.0 — — Dedicated 2,861 6.6 — — 2,861 2.8 — — Refrigerated 2,147 4.9 — — 2,147 2.1 — — Intermodal 603 1.4 — — 603 0.6 — — Subtotal 40,587 29,004 99,390 86,111 Swift Non-reportable segments 2,890 6.6 — — 2,890 2.8 — — Consolidated depreciation and amortization of property and equipment $ 43,477 100.0 % $ 29,004 100.0 % $ 102,280 100.0 % $ 86,111 100.0 % No segment asset or liability information is provided as we do not prepare balance sheets by segment, and our chief decision makers do not review segment assets or liabilities to make operating decisions. Geographical Information In the aggregate, operating revenue from the Company's foreign operations was less than 5.0% of consolidated total operating revenue for the quarter ended and year-to-date September 30, 2017 and 2016 . Additionally, long-lived assets on the Company's foreign subsidiaries' balance sheets were less than 5.0% of consolidated total assets as of September 30, 2017 and December 31, 2016 .

Purchase Price Allocation

Purchase Price Allocation	9 Months Ended
	Sep. 30, 2017
Business Combinations [Abstract]
Purchase Price Allocation	Purchase Price Allocation As described in Note 1, we completed the 2017 Merger on September 8, 2017. Based on the evidence available, Knight was designated as the Accounting Acquirer. Pursuant to the 2017 Merger, each share of Swift Class A Common Stock and Swift Class B Common Stock was converted into 0.72 shares of Knight-Swift by means of the Reverse Split. Following the consummation of the 2017 Merger, Knight and Swift stockholders own approximately 46% and 54% , respectively, of the Company. Based on Knight's $40.85 per share closing price on September 8, 2017 and the fair value of Swift equity awards, consisting of outstanding stock options and certain unvested restricted stock units, and noncontrolling interest assumed by the Company totaling $13.2 million , the 0.72 of a combined company share that the Swift stockholders received in respect of each class A share of Swift had a fair value of approximately $4.0 billion . See Note 22 for further discussion related to the treatment of the Swift equity awards assumed pursuant to the 2017 Merger. The purchase price allocation for the 2017 Merger is preliminary and has been allocated based on estimated fair values of the assets acquired and liabilities assumed at the acquisition date, pending the completion of an independent valuation of certain tangible and intangible assets acquired, assessment of lease agreements, certain identified contingent liabilities and the calculation of deferred taxes based upon the underlying tax basis of assets acquired and liabilities assumed and assessment of other tax related items. We expect that, as we obtain more information, the preliminary purchase price allocation disclosed below may change. Any future adjustments to the preliminary purchase price allocation, including changes within identifiable intangible assets or estimation uncertainty impacted by market conditions, may impact future net earnings. The purchase price allocation adjustments can be made through the end of our measurement period, which is not to exceed one year from the acquisition date. The following table summarizes the total fair value consideration transferred (in thousands except per share data): Number of Swift shares outstanding at September 8, 2017 134,765 Swift share conversion ratio 0.72 Swift shares outstanding post-Reverse Split and immediately prior to the 2017 Merger 97,031 Closing price of Knight on September 8, 2017 $ 40.85 Fair value of equity portion of the 2017 Merger consideration $ 3,963,712 Fair Value of Swift equity awards and noncontrolling interest assumed 13,193 Total Fair value of consideration transferred $ 3,976,905 The following is a preliminary summary of the allocation of purchase consideration to the estimated fair value of Swift’s assets acquired and liabilities assumed in the 2017 Merger (in thousands): Fair value of the consideration transferred $ 3,976,905 Cash and cash equivalents $ 28,484 Restricted cash and fixed maturity securities 85,615 Trade and other receivables 411,767 Prepaid expenses 44,564 Other current assets 19,736 Property and equipment 1,522,123 Identifiable intangible assets 1,285,900 Other noncurrent assets 18,537 Total assets 3,416,726 Accounts payable (188,411 ) Accrued liabilities (232,280 ) Claims accruals (306,846 ) Long-term debt and capital lease obligations (894,681 ) Deferred tax liabilities (741,405 ) Other long-term liabilities (18,452 ) Total liabilities (2,382,075 ) Goodwill $ 2,942,254 The goodwill is primarily attributable to Swift’s existing workforce and the synergies expected to arise after the 2017 Merger. These acquired capabilities, when combined with Knight's business, will result in opportunities that allow us to provide services under contracts that could not have been pursued individually by either Knight or Swift. As noted above, our purchase price allocation is preliminary and as such, we have not completed the allocation of goodwill to our reportable segments. The goodwill will not be deductible for tax purposes. The estimated fair value of the acquired identifiable intangible assets is based on a preliminary valuation completed for Swift, along with related tangible assets, using a combination of the income method, cost method and comparable market transactions. Following are the details of the preliminary purchase price allocated to the identifiable intangible assets acquired: Estimated Life Estimated (years) (thousands) Customer relationships 10 - 20 years $ 817,200 Trade name indefinite 468,700 Total identifiable intangible assets $ 1,285,900 We assumed certain claims and contingent liabilities, including legal reserves, at the acquisition date. The fair value of these liabilities is preliminary, and, as we obtain additional information, the fair value of these liabilities may change. In association with the 2017 Merger, we recognized certain merger-related costs, consisting of legal and professional fees, of $12.3 million and $16.5 million for the quarter ended and year-to-date September 30, 2017 , respectively. Additionally, we incurred merger-related bonuses and accelerated stock compensation expense totaling $5.6 million , which is recorded in the "Salaries, wages and benefits" line in the accompanying condensed consolidated statements of income during the quarter ended and year-to-date September 30, 2017, as well as, merger-related statutory filing fees of $0.9 million and $0.1 million in driver-retention expenses recorded within the "Miscellaneous operating expenses" and "Purchased transportation" lines in the accompany condensed consolidated statements of income during the three and nine months ended September 30, 2017. Our condensed consolidated financial statements for the quarter ended and year-to-date September 30, 2017 include Swift's results of operations after September 8, 2017 (closing of the 2017 Merger) through September 30, 2017 . During the quarter ended and year-to-date September 30, 2017 , Swift's total revenue and net loss included within our consolidated operating results was $242.8 million and $5.5 million , respectively. Swift's net loss for this period includes a $16.7 million Impairment charge for the termination of implementation of the Swift Enterprise Resource Planning ("ERP") system, as well as, $2.5 million related to the amortization of intangibles acquired in the 2017 Merger. The following unaudited pro forma information combines the historical operations of Knight and Swift, giving effect to the 2017 Merger and related transactions as if they had been consummated on January 1, 2016, the beginning of the earliest period presented. Year-to-Date September 30, 2017 September 30, 2016 Total revenue $ 3,776,841 $ 3,821,839 Net income $ 83,727 $ 165,613 Diluted earnings per share $ 0.47 $ 0.92 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 and by Swift during the periods presented that were directly related to the 2017 Merger, and related income tax effects of these items. As a result of the 2017 Merger, both Knight and Swift incurred certain merger-related expenses, including professional legal and advisory fees, acceleration of share-based compensation, bonus incentives, severance payments, filing fees and other miscellaneous expenses. These merger-related expenses for both Knight and Swift totaled $57.0 million year-to-date September 30, 2017 and 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 and Swift 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 2017 Merger. The unaudited pro forma condensed combined financial information does not reflect any cost savings that may be realized as a result of the 2017 Merger and also does not reflect any restructuring or integration-related costs to achieve those potential cost savings.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	9 Months Ended
	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill represents the excess of the purchase price of our acquisitions over the fair value of the net assets acquired. The tax benefit from the recognition on the tax return of the amortization of the excess tax goodwill over book goodwill is treated as a reduction in the book basis of goodwill. The changes in the carrying amounts of goodwill were as follows: September 30, 2017 (In thousands) Goodwill at beginning of period $ 47,031 Amortization relating to deferred tax assets (15 ) Goodwill related to 2017 Merger 2,942,254 Goodwill at end of period $ 2,989,270 There were no goodwill impairments recorded year-to-date September 30, 2017 or 2016 . Identifiable intangible assets subject to amortization have been recorded at fair value. Intangible assets related to acquisitions prior 2017 are amortized over a remaining weighted-average amortization period of 7.6 years . Our customer relationship intangible assets related to the 2017 Merger are being amortized over a remaining weighted average amortization period of 19.9 years . Other intangible asset balances were as follows: September 30, December 31, (In thousands) Customer Relationships and Non Compete: Gross carrying amount $ 820,900 $ 3,700 Accumulated amortization (4,029 ) (1,125 ) Customer relationships and non-compete, net $ 816,871 $ 2,575 Trade Name: Gross carrying amount 468,700 — Intangible assets, net $ 1,285,571 $ 2,575 The following table presents amortization of intangible assets related to the 2017 Merger and intangible assets existing prior to the 2017 Merger: Quarter Ended September 30, Year-to-Date September 30, 2017 2016 2017 2016 (In thousands) Amortization of intangible assets related to the 2017 Merger $ 2,529 $ — $ 2,529 $ — Amortization related to intangible assets existing prior to the 2017 Merger 125 125 375 375 Amortization of intangibles $ 2,654 $ 125 $ 2,904 $ 375 Future amortization expense for intangible assets is estimated at $10.5 million for the remainder of 2017, $41.9 million per each of the years 2018 through 2019 and $41.8 million per each of the years 2020 and 2021, and $41.7 million in 2022.

Investments and Related Commitm

Investments and Related Commitments	9 Months Ended
	Sep. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Investments and Related Commitments	Investments and Related Commitments Investment balances included in “Other long-term assets, restricted cash and investments” on our accompanying condensed consolidated unaudited balance sheets were as follows: September 30, 2017 December 31, 2016 (in thousands) Investment in Transportation Resource Partners (TRP) $ 211 $ 214 Investment in Transportation Resource Partners III (TRP III) 2,146 5,882 Investment in Transportation Resource Partners IV (TRP IV) 2,580 1,882 Investment in Transportation Resource Partners CoInvest Partners, (NTI) I, LP (TRP Coinvestment) 8,625 10,000 Investment in Transportation Resource Partners CoInvest Partners, (QLS) I, LP (TRP Coinvestment QLS) 7,145 9,735 $ 20,707 $ 27,713 In 2003, Knight signed a partnership agreement with Transportation Resource Partners ("TRP"), a company that makes privately negotiated equity investments. Per the original partnership agreement, Knight committed to invest $5.0 million in TRP. In 2006, Knight increased the commitment amount to $5.5 million . We recorded no impairment in the quarter ended September 30, 2017 , and $67,000 impairment was recorded in the quarter ended September 30, 2016 . We recorded impairment of $3,000 and $67,000 during year-to-date September 30, 2017 and 2016, respectively. Our investment in TRP is accounted for using the cost method, as the level of influence over the operations of TRP is minor, and the balance is included in "Other long-term assets, restricted cash and investments" on our accompanying condensed consolidated unaudited balance sheets. In 2008, Knight formed Knight Capital Growth, LLC and committed $15.0 million to invest in another partnership managed and operated by the managers and principals of TRP. This partnership, Transportation Resource Partners III, LP ("TRP III"), is focused on investment opportunities similar to TRP. In 2015, TRP III released Knight from $2.1 million of its outstanding commitment. As of September 30, 2017 , we have contributed approximately $11.1 million to TRP III, leaving an outstanding commitment of $1.8 million . We recorded income from our investment in TRP III of approximately $0.4 million , and received distributions of $0.8 million for the quarter ended September 30, 2017 , and income of approximately $32,100 for the quarter ended September 30, 2016 . We recorded income from our investment in TRP III of approximately $1.5 million , and received distributions of $5.3 million for year-to-date September 30, 2017 , and recorded income of approximately $0.2 million , and received $0.4 million distributions for year-to-date September 30, 2016 . Our investment in TRP III is accounted for using the equity method, and the carrying value of our investment is included in "Other long-term assets, restricted cash and investments" on our accompanying condensed consolidated unaudited balance sheets. In 2015, Knight committed to invest in another TRP partnership, TRP Capital Partners, LP (“TRP IV”). TRP IV is managed and operated by the managers and principals of TRP and TRP III, and is focused on similar investment opportunities. Knight committed to contribute a total of $4.9 million to TRP IV, and have contributed approximately $2.8 million , including approximately $1.1 million in year-to-date September 30, 2017 , leaving an outstanding commitment of approximately $2.1 million as of September 30, 2017 . We received distributions from TRP IV of approximately $0.4 million , and recorded impairment of approximately $53,000 in year-to-date September 30, 2017 . Our investment in TRP IV is accounted for using the cost method, as the level of influence over the operations of TRP IV is minor, and the balance is included in "Other long-term assets, restricted cash and investments" on our accompanying condensed consolidated unaudited balance sheets. In the first quarter of 2016, Knight committed to invest in another TRP partnership, TRP CoInvest Partners, (NTI) I, LP (“TRP Coinvestment”). The new partnership is managed and operated by the managers and principals of the other TRP partnerships, and is focused on similar investment opportunities. Knight committed to contribute, and has paid a total of, $10.0 million to the new partnership, leaving no outstanding commitment as of September 30, 2017 . Knight recorded a loss from our investment in TRP Coinvestment of approximately $0.3 million in the quarter ended September 30, 2017 , and no income or loss was recorded in the quarter ended September 30, 2016 . We recorded a loss from our investment in TRP Coinvestment of approximately $1.4 million in year-to-date September 30, 2017 , and no income or loss was recorded in year-to-date September 30, 2016 . Our investment in TRP Coinvestment is accounted for using the equity method, and the carrying value is included in "Other long-term assets, restricted cash and investments" on our accompanying condensed consolidated unaudited balance sheets. In the third quarter of 2016, Knight committed to invest in another TRP partnership, TRP CoInvest Partners, (QLS) I, LP (“TRP Coinvestment QLS”). The new partnership is managed and operated by the managers and principals of the other TRP partnerships, and is focused on similar investment opportunities. Knight committed to contribute, and has paid a total of, $9.7 million to the new partnership, leaving no outstanding commitment as of September 30, 2017 . We recorded income from our investment in TRP Coinvestment QLS of approximately $0.2 million in the quarter ended September 30, 2017 , and we recorded income from our investment in TRP Coinvestment QLS of approximately $1.5 million , and received distributions of approximately $4.1 million f or year-to-date September 30, 2017 . Our investment in TRP Coinvestment is accounted for using the equity method, and the carrying value is included in "Other long-term assets, restricted cash and investments" on our accompanying condensed consolidated unaudited balance sheets.

Marketable Equity Securities

Marketable Equity Securities	9 Months Ended
	Sep. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Marketable Equity Securities	Marketable Equity Securities Historically, Knight, from time to time, held certain marketable equity securities classified as available-for-sale securities, which are recorded at fair value with unrealized gains and losses, net of tax, as a component of "Accumulated other comprehensive income" in stockholders' equity on the accompanying condensed consolidated unaudited balance sheets. Realized gains and losses on available-for-sale securities are included in the determination of net income. We use specific identification to determine the cost of securities sold, or amounts reclassified out of accumulated other comprehensive income into earnings and included in “Other income” on the accompanying condensed consolidated statements of income. The following table shows our realized gains during the quarter ended and year-to-date September 30, 2017 and 2016 , on certain securities that were classified as available-for-sale: Quarter Ended September 30, Year-to-Date September 30, 2017 2016 2017 2016 Realized Gains: (In thousands) Sales proceeds $ — $ 2,220 $ — $ 7,403 Cost of securities sold — 796 — 2,909 Realized gain $ — $ 1,424 $ — $ 4,494 Realized gain, net of taxes $ — $ 878 $ — $ 2,771 During the quarter ended September 30, 2016, Knight disposed of its holdings in available-for-sale equity investments, leaving no balance on the accompanying condensed consolidated unaudited balance sheets as of September 30, 2017 or December 31, 2016 .

Restricted Investments

Restricted Investments	9 Months Ended
	Sep. 30, 2017
Schedule of Investments [Abstract]
Restricted Investments	Restricted Investments The following table presents the cost or amortized cost, gross unrealized gains and temporary losses, and estimated fair value of our restricted investments: September 30, 2017 Gross Unrealized Cost or Amortized Gains Temporary Estimated Fair Value (In thousands) United States corporate securities $ 16,033 $ — $ (5 ) $ 16,028 Municipal bonds 4,990 1 (2 ) 4,989 Negotiable certificate of deposits 1,280 — — 1,280 Restricted investments, held to maturity $ 22,303 $ 1 $ (7 ) $ 22,297 Refer to Note 21 for additional information regarding fair value measurements of restricted investments, money market fund and debt securities recorded in "Other long-term assets, restricted cash and investments" on the condensed consolidated unaudited balance sheet. As of September 30, 2017 , the contractual maturities of the restricted investments were one year or less. There were 29 securities that were in an unrealized loss position for less than twelve months as of September 30, 2017 . We did not recognize any impairment losses for year-to-date September 30, 2017 .

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Effective Tax Rate — The effective tax rate for the quarter ended September 30, 2017 and September 30, 2016 was (43.5)% and 38.1% , respectively. We recognized discrete items relating to stock compensation deductions and the impact of state tax rate changes on deferred taxes benefiting the respective quarters. The year-to-date September 30, 2017 and September 30, 2016 effective tax rate were 32.1% and 39.2% , respectively. We recognized discrete items relating to stock compensation deductions and the impact of state tax rate changes on deferred taxes benefiting those periods. We believe it is reasonably possible that a decrease of up to $0.7 million in unrecognized tax benefits related to federal tax credit claims for refund may be necessary within the coming year due to settlement of such tax credit claims with the relevant taxing authority. Interest and Penalties — Accrued interest and penalties related to unrecognized tax benefits as of September 30, 2017 and December 31, 2016 were approximately $1.7 million and $0.4 million , respectively. Tax Examinations — Certain of our subsidiaries are currently under examination by various state jurisdictions for tax years ranging from 2011 through 2015 . At the completion of these examinations, management does not expect any adjustments that would have a material impact on our effective tax rate. Years subsequent to 2011 remain subject to examination.

Property and Equipment

Property and Equipment	9 Months Ended
	Sep. 30, 2017
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and Equipment To ensure that our facilities remain modern and efficient, we periodically have facility upgrades, or new construction, in process at our various terminals or corporate headquarters locations. Until these projects are completed, we consider these to be assets not yet placed in service and they are not depreciated. Once they are placed into service, we depreciate them according to our depreciation policy. At September 30, 2017 and December 31, 2016 , we had approximately $7.0 million and $13.0 million , respectively, of facility construction in process assets included under "Buildings and building improvements” on the accompanying condensed consolidated unaudited balance sheets.

Assets Held for Sale

Assets Held for Sale	9 Months Ended
	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Assets Held for Sale	Assets Held for Sale Revenue equipment that is not utilized in continuing operations and is held for sale is classified as "Assets held for sale" on the accompanying condensed consolidated unaudited balance sheets. Assets held for sale at September 30, 2017 and December 31, 2016 , totaled $24.9 million and $9.6 million , respectively. Assets held for sale are no longer subject to depreciation, and are recorded at the lower of depreciated carrying value or fair market value less selling costs. We expect to sell these assets and replace them with new assets within twelve months of being classified as "Assets held for sale."

Notes Receivable

Notes Receivable	9 Months Ended
	Sep. 30, 2017
Receivables [Abstract]
Notes Receivables	Notes Receivable We provide financing to independent contractors and third parties on equipment sold or leased under our equipment sale program. Most of the notes are collateralized and are due in weekly installments, comprised of principal and interest payments. Interest rates are set forth in the contracts and generally range from 2.0% to 20.0% . Notes receivable are included in "Notes receivable, net" and "Notes receivable, long-term" in the condensed consolidated balance sheets and were comprised of: September 30, 2017 December 31, 2016 (In thousands) Notes receivable from independent contractors $ 10,910 $ 1,039 Notes receivable from third parties 8,292 2,808 Gross notes receivable 19,202 3,847 Allowance for doubtful notes receivable (559 ) (240 ) Total notes receivable, net of allowance $ 18,643 $ 3,607 Current portion, net of allowance 5,984 560 Long-term portion $ 12,659 $ 3,047

Accounts Receivable Securitizat

Accounts Receivable Securitization	9 Months Ended
	Sep. 30, 2017
Transfers and Servicing [Abstract]
Accounts Receivable Securitization	Accounts Receivable Securitization On December 10, 2015, SRCII, Swift's wholly-owned subsidiary, entered into the 2015 RSA, which further amended the 2013 RSA. The parties to the 2015 RSA include SRCII as the seller, Swift Transportation Services, LLC as the servicer, the various conduit purchasers, the various related committed purchasers, the various purchaser agents, the various letters of credit participants, and PNC Bank, National Association as the issuing bank of letters of credit and as administrator. Pursuant to the 2015 RSA, Swift's receivable originator subsidiaries sell, on a revolving basis, undivided interests in all of their eligible accounts receivable to SRCII. In turn, SRCII sells a variable percentage ownership interest in the eligible accounts receivable to the various purchasers. The facility qualifies for treatment as a secured borrowing under ASC 860, Transfers and Servicing. As such, outstanding amounts are classified as liabilities on our condensed consolidated unaudited balance sheets. As of September 30, 2017, Knight and its subsidiaries are not parties to the 2015 RSA. Refer to Note 21 for information regarding the fair value of the 2015 RSA. As of September 30, 2017 , interest accrued on the aggregate principal balance at a rate of 1.8% . Program fees and unused commitment fees are recorded in "Interest expense" in the condensed consolidated statements of income. We incurred program fees of $0.4 million related to the 2015 RSA during the quarter ended and year-to-date September 30, 2017 . The 2015 RSA is subject to customary fees and contains various customary affirmative and negative covenants, representations and warranties, and default and termination provisions. Collections on the underlying receivables are held for the benefit of SRCII and The Purchasers in the facility and are unavailable to satisfy the Company's claims.

Debt and Financing

Debt and Financing	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Debt and Financing	Debt and Financing Knight-Swift Credit Agreement On September 29, 2017 , we entered into a $1.2 billion unsecured credit facility with a group of banks (the “2017 Agreement”) replacing Swift’s previous secured credit facility (the “2015 Agreement”) and Knight’s previous unsecured credit facility (the “2013 Agreement”). The 2017 Agreement includes a $800.0 million revolving line of credit maturing October 2022 (the "Revolver"), $85.0 million of which was drawn at closing, and a $400 million Term Loan (the "Term Loan") maturing October 2020 . There are no scheduled principal payments on the Term Loan until its maturity. The 2015 Agreement included a $600.0 million revolving line of credit maturing July 2020 ( $35.0 million outstanding as of the closing of the 2017 Agreement) and a $680.0 million Term Loan A ( $450.0 million face value outstanding as of closing). Additionally, prior to the 2017 Merger, the 2013 Agreement included a $300.0 million revolving line of credit maturing August 2019 , with no balance outstanding as of the closing of the 2017 Agreement. Upon closing of the 2017 Agreement, proceeds from our $400.0 million Term Loan, $85.0 million drawn from the Revolver, and $3.4 million cash on hand were used to pay off the then-outstanding balances and accrued interest and fees under the 2015 Agreement, as well as certain transaction fees and expenses associated with the 2017 Agreement. Under the 2017 Agreement, the interest rate applicable to the Revolver and the Term Loan is subject to a leverage-based pricing grid and equaled the LIBOR rate plus 1.125% at closing, which is 0.375% lower than the rate applicable under the Swift 2015 Agreement and 0.50% higher than the rate applicable under the 2013 Agreement as of the closing of the 2017 Agreement. The following table presents the key terms of the 2017 Agreement: Description Term Loan Revolver (2) (Dollars in thousands) Maximum borrowing capacity $400,000 $800,000 Final maturity date October 2, 2020 October 3, 2022 Interest rate base LIBOR LIBOR Interest rate minimum margin (1) 0.875% 0.875% Interest rate maximum margin (1) 1.50% 1.50% Minimum principal payment – amount $— $— Minimum principal payment – frequency Once Once Minimum principal payment – commencement date October 2, 2020 October 3, 2022 ____________ (1) The interest rate margin for the Term Loan and the Revolver is based on our consolidated leverage ratio. As of September 30, 2017 , interest accrued at 2.36% on the Term Loan and 2.36% on the Revolver. (2) The commitment fee for the unused portion of the Revolver is based on our consolidated leverage ratio and ranges from 0.07% to 0.20% . As of September 30, 2017 , commitment fees on the unused portion of the Revolver accrued at 0.13% and outstanding letter of credit fees accrued at 1.13% . Pursuant to the 2017 Agreement, the Revolver and the Term Loan contain certain financial covenants with respect to a maximum net leverage ratio and a minimum consolidated interest coverage ratio. The 2017 Agreement provides flexibility regarding the use of proceeds from asset sales, payment of dividends, stock repurchases and equipment financing. In addition to the financial covenants, the 2017 Agreement includes usual and customary events of default for a facility of this nature and provides that, upon the occurrence and continuation of an event of default, payment of all amounts payable under the 2017 Agreement may be accelerated, and the lenders' commitments may be terminated. The 2017 Agreement contains certain usual and customary restrictions and covenants relating to, among other things, dividends (which would be restricted only if a default or event of default had occurred and was continuing or would result therefrom), liens, affiliate transactions, and other indebtedness. Borrowings under the 2017 Agreement are guaranteed by Knight-Swift Transportation Holdings Inc., Swift Transportation Company, Interstate Equipment Leasing, Knight Transportation, Inc. and our domestic subsidiaries (other than our captive insurance subsidiaries, driver academy subsidiary, and our bankruptcy-remote special purpose subsidiary). Knight Line of Credit Prior to the closing of the 2017 Agreement, our 2013 Agreement included a $300.0 million revolving line of credit ("Knight Revolver"), which permitted revolving borrowings and letters of credit. The scheduled maturity of the Knight Revolver was August 2019 , which was accelerated to December 31, 2017 in connection with the closing of the 2017 Merger. Knight incurred interest on borrowings under the Knight Revolver at either the prime rate or LIBOR plus 0.625% , determined by Knight at the time of borrowing. We had no outstanding borrowings under the Knight Revolver as of September 30, 2017 as a result of its cancellation pursuant to the 2017 Agreement, compared to $18.0 million as of December 31, 2016 , recorded within the "Revolving line of credit" of our condensed consolidated unaudited balance sheet. The weighted average variable annual percentage rate for amounts borrowed during year-to-date September 30, 2017 was 1.40% . Other than our accounts receivable securitization, as discussed in Note 14 , and our outstanding capital lease obligations as discussed in Note 17 , our long-term debt consisted of the following: September 30, December 31, (In thousands) Term Loan, due October 2020, net of $704 deferred loan costs (1) $ 399,296 $ — Other 453 — Long-term debt 399,749 — Less: current portion of long-term debt (30 ) — Long-term debt, less current portion $ 399,719 $ — September 30, December 31, (In thousands) Long-term debt $ 399,749 $ — Knight Revolver, due August 2019 (1) (2) — 18,000 Knight-Swift Revolver, due October 2022 (1) (3) 85,000 — Long-term debt, including revolving line of credit $ 484,749 $ 18,000 ____________ (1) Refer to Note 21 for information regarding the fair value of long-term debt. (2) Knight also had outstanding letters of credit under the Knight Revolver of $31.3 million at December 31, 2016 , issued to various regulatory authorities and insurance carriers in connection with Knight's self-insurance programs. (3) The Company also had outstanding letters of credit under the Revolver of $124.8 million at September 30, 2017 for the benefit of regulatory authorities, insurance companies and state departments of insurance for the purpose of satisfying certain collateral requirements, primarily related to our automobile, workers' compensation, and general insurance liabilities.

Deferred Loan Costs

Deferred Loan Costs	9 Months Ended
	Sep. 30, 2017
Debt Issuance Costs, Net [Abstract]
Deferred Loan Costs	Deferred Loan Costs The following table presents the classification of deferred loan costs in our condensed consolidated balance sheets: September 30, December 31, (In thousands) ASSETS: Other assets $ 1,608 $ — LIABILITIES: Long-term debt, less current portion 704 — Total deferred loan costs $ 2,312 $ —

Leases

Leases	9 Months Ended
	Sep. 30, 2017
Leases [Abstract]
Leases	Leases We finance a portion of our revenue equipment under capital and operating leases and certain terminals under operating leases. Capital Leases (as Lessee) — Our capital leases are typically structured with balloon payments at the end of the lease term equal to the residual value we are contracted to receive from certain equipment manufacturers upon sale or trade back to the manufacturers. If we do not receive proceeds of the contracted residual value from the manufacturer, we are 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 - current portion" and "Capital lease obligations - less current portion" in the condensed consolidated unaudited balance sheets. As of September 30, 2017 , the leases were collateralized by revenue equipment with a cost of $178.5 million and accumulated amortization of $1.9 million . Knight had no capital leases as of December 31, 2016, and therefore no revenue equipment was held as collateral. Amortization of equipment under capital leases is included in "Depreciation and amortization of property and equipment" in our condensed consolidated unaudited income statements. Operating Leases (as Lessee) — Rent expense related to operating leases was $15.4 million and $1.3 million for the quarter ended September 30, 2017 and 2016 , respectively. Year-to-date September 30, 2017 and 2016 rent expense related to operating leases was $17.9 million and $3.7 million , respectively. As of September 30, 2017 , annual future minimum lease payments for all noncancelable leases were: Operating Capital (In thousands) 2017 $ 55,912 $ 16,198 2018 177,778 51,008 2019 122,607 61,281 2020 74,832 14,984 2021 39,130 30,848 Thereafter 58,984 29,463 Future minimum lease payments $ 529,243 $ 203,782 Less: amounts representing interest (13,681 ) Present value of minimum lease payments 190,101 Less: current portion (54,561 ) Capital lease obligations, less current portion $ 135,540 Operating Leases (as Lessor) — Our wholly-owned financing subsidiaries lease revenue equipment to our independent contractors under operating leases. Annual future minimum lease payments receivable under operating leases for the periods noted below were: (In thousands) 2017 $ 25,061 2018 69,208 2019 35,119 2020 18,383 2021 5,196 Thereafter — Future minimum lease payments receivable $ 152,967 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 owner-operators default on their leases, the Company typically re-leases the equipment to other owner-operators. As such, future minimum lease payments reflect original leases and re-leases.

Contingencies and Legal Proceed

Contingencies and Legal Proceedings	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Contingencies and Legal Proceedings	Contingencies and Legal Proceedings We are involved in certain claims and pending litigation primarily arising in the normal course of business. The majority of these claims relate to workers' compensation, auto collision and liability, physical damage, and cargo damage, as well as certain class action litigation in which plaintiffs allege failure to provide meal and rest breaks, unpaid wages, unauthorized deductions, and other items. Legal Proceedings The Company is involved in a number of legal proceedings. The Company has made accruals with respect to these matters where appropriate, which are reflected in the condensed consolidated unaudited financial statements. We have recorded an aggregate accrual of approximately $126.2 million relating to our outstanding legal proceedings as of September 30, 2017 . For some matters, a liability is not probable or the amount cannot be reasonably estimated and therefore an accrual has not been made. However, where a liability is reasonably possible and may be material, such matters have been disclosed. The Company may enter into discussions regarding settlement of these matters, and may enter into settlement agreements if it believes settlement is in the best interest of the Company and its stockholders. Unless stated otherwise, the matters, or groups of related matters, discussed below, if decided adversely to or settled by the Company, individually or in the aggregate, may result in a liability material to the Company's financial condition or results of operations. EMPLOYEE COMPENSATION AND PAY PRACTICES MATTERS Washington Overtime Class Actions The plaintiffs allege one or more of the following, pertaining to Washington state-based drivers: that Swift 1) failed to pay minimum wage; 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. 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 Recent Developments and Current Status On August 29, 2017, the Parties in the Slack case reached a settlement. On October 10, 2017, the court granted a motion for preliminary approval of the settlement. The court set a date of January 29, 2018 for the fairness hearing. The likelihood that a loss has been incurred in the Slack matter is probable. ___________ (1) Individually and on behalf of all others similarly situated. INDEPENDENT CONTRTACTOR MATTERS Ninth Circuit Independent Contractor Misclassification Class Action The putative class alleges that Swift misclassified independent contractors as independent contractors in violation of the FLSA and various state laws, and that such independent contractors should be considered employees. 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. 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 January 2017, the district court issued an order finding that the plaintiffs had signed contracts of employment and thus the case could properly proceed in court. Swift has appealed this decision to the Ninth Circuit and the parties have discussed settlement. Based on the above, the likelihood that a loss has been incurred is probable. INDEPENDENT CONTRTACTOR MATTERS Utah Collective and Individual Arbitration The plaintiffs allege that the Central Parties (defined below) misclassified independent contractor drivers as independent contractors and were therefore liable to these drivers for minimum wages and other employee benefits under the FLSA. The complaint also alleges a federal forced labor claim under U.S.C. §1589 and §1595, as well as fraud and other state-law claims. Plaintiff(s) Defendant(s) Date instituted Court or agency currently pending in Gabriel Ciluffo, Kevin Shire, and Bryan Ratterree (1) Central Refrigerated Service, Inc., Central Leasing, Inc., Jon Isaacson, and Jerry Moyes (the "Central Parties"), as well as Swift Transportation Company June 1, 2012 American Arbitration Association Recent Developments and Current Status In October 2016, the arbitrator ruled that approximately 1,300 Central Refrigerated Service, Inc. drivers were improperly classified as independent contractors, when they should have been classified and compensated as employees. The arbitrator ruled that damages could ultimately be assessed in a collective proceeding and denied Swift’s motion to decertify the collective proceeding. On April 14, 2017, the parties reached a settlement of the matter. The parties are currently pursuing court approval of that settlement. The likelihood that a loss has been incurred is probable. ___________ (1) Individually and on behalf of all others similarly situated. Self Insurance We are insured against auto liability (“AL”) claims under a primary self-insured retention ("SIR") policy. For our Knight AL claims, we have SIR ranging from $1.0 million to $3.0 million per occurrence and in some years, depending on the applicable policy year, we have been responsible for aggregate losses up to $1.5 million within the primary AL layer. For the policy period March 1, 2017 to March 1, 2018, the Knight SIR is $1.0 million , subject to an annual aggregate limit. 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. We secured excess liability coverage up to $130.0 million per occurrence for the Knight policy periods March 1, 2017 to March 1, 2018, and March 1, 2016 to March 1, 2017. We also carry a $2.5 million aggregate deductible for any loss or losses within the excess coverage layer. For our Swift AL claims, we 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. We are self-insured for workers' compensation coverage. In the first quarter of 2016, the Knight self-retention level was increased from a maximum $0.5 million per occurrence to a maximum $1.0 million per occurrence. Swift maintains statutory coverage limits, subject to a $5.0 million SIR for each accident or disease. Additionally, through Knight, we also maintain primary and excess coverage for employee medical expenses and hospitalization, with self-insured retention of $0.2 million per claimant in 2017 and 2016. As of January 1, 2015, Swift was fully insured on its medical benefits, subject to contributed premiums.

Joint Ventures

Joint Ventures	9 Months Ended
	Sep. 30, 2017
Equity Method Investments and Joint Ventures [Abstract]
Joint Ventures	Joint Ventures In 2014, Knight formed an Arizona limited liability company, now known as Kold Trans, LLC, for the purpose of expanding its refrigerated trucking business. Knight is entitled to 80.0% of the profits of the entity and has effective control over the management of the entity. In accordance with ASC 810-10-15-8, Consolidation , we consolidate the financial activities of this entity into these condensed consolidated unaudited financial statements. The noncontrolling interest for this entity is presented as a separate component of the condensed consolidated unaudited financial statements. In 2010, Knight partnered with a non-related investor to form an Arizona limited liability company for the purpose of sourcing commercial vehicle parts. Knight contributed $26,000 to acquire 52.0% ownership of this entity. In accordance with ASC 810-10-15-8, Consolidation , we consolidate the financial activities of this entity into the condensed consolidated unaudited financial statements. The noncontrolling interest for this entity is presented as a separate component of the condensed consolidated unaudited financial statements.

Share Repurchase Programs

Share Repurchase Programs	9 Months Ended
	Sep. 30, 2017
Class of Stock Disclosures [Abstract]
Share Repurchase Programs	Share Repurchase Programs In 2011, Knight's board of directors unanimously authorized the repurchase of up to 10.0 million shares of Knight Common Stock (the "Knight Repurchase Plan"). The following table presents repurchases of Knight Common Stock under Knight Repurchase Plan for the quarter ended and year-to-date September 30, 2016 : Quarter Ended September 30, Year-to-Date September 30, Share Repurchase Program 2016 2016 Authorized Amount Board Approval Date Shares Amount Shares Amount (In thousands) (In thousands) 10,000 May 19, 2011 100 $ 3,300 1,600 $ 39,900 There were no share repurchases under the Knight Repurchase Plan in 2017 . In connection with the 2017 Merger, the Knight Repurchase Plan was terminated. In February 2016, Swift's board of directors authorized the repurchase of up to $150.0 million of Swift Class A Common Stock (the "Swift Repurchase Plan"). Following the 2017 Merger, the Swift Repurchase Plan remained in effect. As of September 30, 2017 approximately $62.9 million remained available under the Swift Repurchase Plan to repurchase shares of our Class A Common Stock. We did not repurchase any shares of our Class A Common Stock after the 2017 Merger under the Swift Repurchase Plan.

Fair Value Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurement	Fair Value Measurement The following table presents the carrying amounts and estimated fair values of our financial instruments: September 30, 2017 December 31, 2016 Carrying Estimated Carrying Estimated (In thousands) Financial Assets: Restricted investments (1) $ 22,303 $ 22,297 $ — $ — Money market funds (2) 1,597 1,597 1,385 1,385 Debt securities - municipal securities (2) 1,728 1,728 1,903 1,903 Financial Liabilities: Term Loan, due October 2020 (3) 399,296 400,000 — — 2015 RSA, due January 2019 285,000 285,000 — — Knight Revolver, due August 2019 — — 18,000 18,000 Revolver, due October 2022 85,000 85,000 — — ____________ The carrying amounts of the financial instruments shown in the table are included in the condensed consolidated balance sheets, as follows: (1) Restricted investments are included in "Restricted investments, held to maturity, amortized cost." (2) Items included within "Other long-term assets, restricted cash and investments." (3) Carrying value is net of $0.7 million deferred loan costs as of September 30, 2017 . Recurring Fair Value Measurements — The following table depicts the level in the fair value of assets measured on a recurring basis as of September 30, 2017 and December 31, 2016 : Fair Value Measurements at Reporting Date Using: Estimated Level 1 Inputs Level 2 Inputs Level 3 Inputs (In thousands) As of September 30, 2017 Money market funds $ 1,597 $ 1,597 $ — $ — Debt securities - municipal securities 1,728 — 1,728 — As of December 31, 2016 Money market funds $ 1,385 $ 1,385 $ — $ — Debt securities - municipal securities 1,903 — 1,903 — As of September 30, 2017 and December 31, 2016 , there were no liabilities on our condensed consolidated unaudited balance sheets estimated at fair value that were measured on a recurring basis. Nonrecurring Fair Value Measurements — 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 September 30, 2017 : Fair Value Measurements at Reporting Date Using: Estimated Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Gains (Losses) (In thousands) As of September 30, 2017 Software (1) $ — $ — $ — $ — $ (16,746 ) ____________ (1) During the quarter ended September 30, 2017 , we terminated the implementation of the Swift ERP system. This resulted in a pre-tax impairment loss of $16.7 million , which was recorded in "Impairments" within operating income in the condensed consolidated unaudited statements of income. As of September 30, 2017 , there were no major categories of liabilities on the Company's condensed consolidated unaudited balance sheets estimated at fair value that were measured on a nonrecurring basis. As of December 31, 2016 , there were no major categories of assets or liabilities on the Company's consolidated unaudited balance sheets estimated at fair value that were measured on a nonrecurring basis.

Stock Compensation Expense

Stock Compensation Expense	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Compensation Expense	Stock Compensation Expense Before the 2017 Merger, Knight and Swift granted share-based awards under their respective share-based compensation plans, including the Knight Amended and Restated 2003 Stock Option Plan, the Knight 2012 Equity Compensation Plan, the Knight Amended and Restated 2015 Omnibus Incentive Plan, the Swift 2007 Omnibus Incentive Plan (collectively, the “Legacy Plans”), and the Swift 2014 Omnibus Incentive Plan (the “2014 Plan”). In connection with the 2017 Merger, the securities registered under the Legacy Plans were deregistered, and no future awards may be made under the Legacy Plans. Any outstanding award granted under a Legacy Plan has been assumed by the combined company and continues to be governed by such Legacy Plan until such awards have been exercised, forfeited, cancelled, or have otherwise expired or terminated. Currently, the combined company’s only share-based incentive plan under which share-based awards may be granted is our 2014 Plan. The 2014 Plan was adopted by the Swift board in March 2014, approved by the Swift stockholders in May 2014, and replaced Swift's 2007 Omnibus Incentive Plan. The 2014 Plan permits the payment of cash incentive compensation and authorizes the granting of stock options, stock appreciation rights, restricted stock and restricted stock units, performance shares and performance units, cash-based awards, and stock-based awards to the Company's employees and non-employee directors. As of September 30, 2017 , the aggregate number of shares remaining available under the 2014 Plan was approximately 3.0 million shares. Pursuant to the Merger Agreement, on September 8, 2017 (the "Merger Date"), from an accounting perspective (i) each outstanding Swift stock option, fully vested as a result of the 2017 Merger, was converted into a stock option to acquire the Company's shares using a 0.72 -for-one share consolidation ratio and adjusting the exercise price using the same consolidation ratio, (ii) each outstanding unvested Swift restricted stock award was converted into an unvested restricted stock award of the Company using the 0.72 -for-one share consolidation ratio, (iii) each outstanding unvested Swift restricted stock unit was converted into an unvested restricted stock unit of the Company using the 0.72 -for-one share consolidation ratio, and (iv) each outstanding unvested Swift performance share unit was converted into an unvested performance share unit of the Company using the 0.72 -for-one consolidation ratio. Except for the conversion of stock options, unvested restricted stock awards, unvested restricted stock units, and unvested performance share units discussed herein, the material terms of the awards remained unchanged. In accordance with authoritative guidance on accounting for stock-based compensation, we revalued the awards upon the Merger closing and allocated the revised fair value between purchase consideration and continuing compensation expense based on the ratio of service performed through the Merger Date over the total service period of the awards. The revised fair value allocated to post-merger services resulted in incremental expense, which is recognized over the remaining service period of the awards. The total value of Swift awards earned as of the Merger Date included as purchase consideration was $13.1 million . The total value of Swift awards not earned as of the Merger Date was $6.3 million , which will be expensed over the remaining future vesting period. Of this amount, $0.1 million was recorded on the salaries, wages and benefits expense line in the condensed consolidated statement of income for the three and nine months ended September 30, 2017. Refer to Note 1 to the consolidated financial statements for further information regarding the 2017 Merger. Pursuant to the Merger Agreement, on the Merger Date, from a legal perspective (i) each outstanding vested and unvested Knight stock option was assumed by the Company and automatically converted into a stock option to acquire an equal number of Company shares, (ii) each outstanding Knight restricted stock awards was assumed by the Company and automatically converted into a restricted stock award of the Company, (iii) each outstanding vested and unvested Knight restricted stock unit award was assumed by the Company and automatically converted into a restricted stock unit award of the Company, and (iv) each outstanding vested and unvested Knight performance unit award was assumed by the Company and automatically converted into a performance unit award of the Company. Except for the conversion of stock options, restricted stock awards, restricted stock unit awards, and performance unit awards discussed herein, the material terms of the awards remained unchanged. Certain of the Knight performance unit awards vested upon the consummation of the 2017 Merger, as described below. The following table shows the stock compensation expense categorized by unit: Quarter Ended September 30, Year-to-Date September 30, 2017 2016 2017 2016 (In thousands) Stock compensation expense for options, net of forfeitures $ 480 $ 434 $ 1,309 $ 1,318 Stock compensation expense for restricted stock units and performance restricted stock units, net of forfeitures 1,340 112 2,084 1,808 Total stock compensation expense, net of forfeitures $ 1,820 $ 546 $ 3,393 $ 3,126 Our policy is to recognize compensation expense on a straight-line basis over the requisite service period for the entire award. As of September 30, 2017 , we have approximately $4.4 million of unrecognized compensation expense related to unvested options. We expect to recognize this cost over a weighted-average period of 1.9 years and a total period of 3.7 years . We have approximately $15.6 million of unrecognized compensation expense related to restricted stock unit awards, which we expect to recognize over a weighted-average period of 2.4 years and a total period of 5.3 years . We do not have unrecognized compensation cost related to unvested performance restricted stock units (“PRSUs”). A total of 497,421 and 569,480 stock options were granted year-to-date September 30, 2017 and 2016 , respectively. As a result of the 2017 Merger, we also assumed 528,466 Swift stock options. We received approximately $9.7 million in cash from the exercise of stock options during year-to-date September 30, 2017 , compared to $9.3 million for the same period in 2016 . The following table is a summary of the option award activity under our equity compensation plans: Option Totals Weighted Average Exercise Outstanding as of December 31, 2016 1,737,400 $ 23.19 Granted 497,421 33.35 Assumed Swift stock options 528,466 21.93 Exercised (515,012 ) 21.83 Forfeited (169,616 ) 27.35 Outstanding as of September 30, 2017 2,078,659 $ 25.30 The fair value of each option grant is estimated on the grant date using the Black-Scholes option valuation model. Listed below are the weighted-average assumptions used for the fair value computation: Year-to-Date September 30, 2017 2016 Dividend yield (1) 0.72 % 0.99 % Expected volatility (2) 27.95 % 27.91 % Risk-free interest rate (3) 1.49 % 0.90 % Expected term (4) 3.22 years 2.74 years Weighted-average fair value of options granted $ 6.78 $ 4.28 ____________ (1) Dividend yield - the dividend yield is based on our historical experience and future expectation of dividend payouts. (2) Expected volatility - we analyzed the volatility of our stock using historical data. (3) Risk-free interest rate - the risk-free interest rate assumption is based on U.S. Treasury securities at a constant maturity with a maturity period that most closely resembles the expected term of the stock option award. (4) Expected term - the expected term of employee stock options represents the weighted-average period the stock options are expected to remain outstanding and has been determined based on an analysis of historical exercise behavior. A total of 124,145 and 10,222 restricted stock unit awards were granted during year-to-date September 30, 2017 and 2016 , respectively. As a result of the 2017 Merger, we also assumed 168,488 Swift restricted stock unit awards. The following table is a summary of the restricted stock unit award activity under our equity compensation plans for year-to-date September 30, 2017 : Number of Restricted Stock Unit Awards Weighted Average Grant Date Fair Value Outstanding as of December 31, 2016 686,786 $ 16.46 Granted 124,145 33.35 Assumed Swift restricted stock units 168,488 40.85 Vested (126,871 ) 16.77 Forfeited (35,593 ) 21.32 Outstanding as of September 30, 2017 816,955 $ 22.53 The fair value of each restricted stock unit is based on the closing market price on the date of grant, except for the Swift restricted stock unit awards assumed, which were re-measured at the Merger Date. Historically, Knight issued performance restricted stock units ("PRSUs") to selected key employees that could be earned based on achieving performance targets approved annually by Knight's compensation committee. Pursuant to their terms, the PRSUs vested upon the consummation of the 2017 Merger. Although all outstanding PRSU awards vested on the Merger Date, only the 2014 award was expensed and paid out. At the time of the 2017 Merger, the performance measurement period for the 2014 award had ended, while the performance measurement period for the 2015 and 2016 awards ends December 31, 2017. Since the performance measurement period related to these awards is not yet complete, the final payouts for the 2015 and 2016 award cannot be finalized, however, based on results through September 30, 2017 , no payout is expected, and therefore, no expense was recognized for these awards during year-to-date September 30, 2017 . No PRSUs were granted year-to-date 2017 and 177,741 PRSUs were granted year-to-date 2016 . Beginning in 2013, Swift granted PRSUs to certain members of executive management. These awards provided each grantee a number of shares of Swift's Class A common stock at the end of a three -year period, based on certain performance criteria established by Swift's compensation committee. As a result of the 2017 Merger, 56,817 outstanding PRSUs were assumed by the combined company. A summary of the PRSU activity under our equity compensation plans for year-to-date September 30, 2017 is presented below: Number of Performance Restricted Stock Unit Awards Weighted Average Grant Date Fair Value Unvested as of December 31, 2016 508,478 $ 25.60 Granted — — Assumed Swift PRSUs 56,817 $ 40.85 Shares earned above target 21,117 — 23.85 Vested (1) (519,483 ) $ 25.53 Cancelled (10,112 ) 25.40 Unvested as of September 30, 2017 56,817 $ 40.85 ____________ (1) During year-to-date September 30, 2017 , 107,967 shares vested and paid out, 329,417 shares vested related to the 2015 and 2016 awards for which the performance measurement period ends December 31, 2017 with no pay out expected, and 82,099 shares vested for certain executive officers for which payout will be at a future date. The fair value of each PRSU grant is estimated on the grant date using the Monte Carlo Simulation valuation model. Listed below are the weighted-average assumptions used for the fair value computation for PRSU's granted in 2016: Year-to-Date September 30, 2016 Dividend yield (1) 0.99 % Expected volatility (2) 27.95 % Average peer volatility (2) 34.37 % Average peer correlation coefficient (3) 0.60 Risk-free interest rate (4) 0.89 % Expected term (5) 2.84 Weighted-average fair value of PRSUs granted $ 23.89 ____________ (1) The dividend yield, used to project stock price to the end of the performance period, is based on our historical experience and future expectation of dividend payouts. Total shareholder return is determined assuming that dividends are reinvested in the issuing entity over the performance period, which is mathematically equivalent to utilizing a 0% dividend yield. (2) We (or peer company) estimated volatility using our (or their) historical share price performance over the remaining performance period as of the grant date. (3) The correlation coefficients are used to model the way in which each entity tends to move in relation to each other; the correlation assumptions were developed using the same stock price data as the volatility assumptions. (4) The risk-free interest rate assumption is based on U.S. Treasury securities at a constant maturity with a maturity period that most closely resembles the expected term of the performance award. (5) Since the Monte Carlo simulation valuation is an open form model that uses an expected life commensurate with the performance period, the expected life of the PRSUs was assumed to be the period from the grant date to the end of the performance period. Non-compensatory Stock Plan: Employee Stock Purchase Plan In 2012, Swift's board of directors adopted and its stockholders approved the Swift Transportation Company 2012 Employee Stock Purchase Plan (the "2012 ESPP"). The 2012 ESPP continues to be administered by the Company. The 2012 ESPP is intended to qualify under Section 423 of the Internal Revenue Code and is considered noncompensatory. Pursuant to the 2012 ESPP, we are authorized to issue up to 1.4 million shares of our common stock to eligible employees who participate in the plan. Employees are eligible to participate in the 2012 ESPP following at least 90 days of employment with us or any of our participating subsidiaries. Under the terms of the 2012 ESPP, eligible employees may elect to purchase common stock through payroll deductions, not to exceed 15% of their gross cash compensation. The purchase price of the common stock is 95% of the common stock's fair market value quoted on the NYSE on the last trading day of each offering period. There are four three -month offering periods corresponding to the calendar quarters. Each eligible employee is restricted to purchasing a maximum of $6,250 of common stock during an offering period, determined by the fair market value of the common stock as of the first day of the offering period, and $25,000 of common stock during a calendar year. Employees who own 5% or more of the total voting power or value of our common stock are restricted from participating in the 2012 ESPP. As of September 30, 2017 , we are authorized to issue an additional 1.2 million shares under the 2012 ESPP.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2017
Related Party Transactions [Abstract]
Related Party Transactions	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 will pay Mr. Moyes a monthly consulting fee of $0.2 million in cash. The amounts were previously included in Swift's "Salaries, wages, and employee benefits " within the non-reportable segments ' income statement. The following schedule is a rollforward of the accrued liability for the consulting fees: September 30, (In thousands) Accrued consulting fees – Jerry Moyes, September 9, 2017 (1) $ 2,825 Additions to accrual — Less: payments — Accrued consulting fees – Jerry Moyes, September 30, 2017 (1) $ 2,825 ____________ (1) The balance is included in "Other liabilities" (noncurrent) and "Accrued liabilities" (current) in the condensed consolidated balance sheet (unaudited), based on the timing of the expected payments. In addition, entities affiliated with our majority shareholder and Board member, Jerry Moyes, include Central Freight Lines, SME Industries, Swift Aircraft Management, Compensi Services, Common Market Trading, LLC, and Southwest Premier Properties. Transactions with these entities that are controlled by and/or are otherwise affiliated with Jerry Moyes, include freight services, facility leases, equipment leases, and other services. • Freight Services Provided by Swift - The rates the Company charges for freight services to each of these companies for transportation services are market rates, which are comparable to rates charged to third-party customers. These transportation services provided to affiliates provide the Company with an additional source of operating revenue at its normal freight rates. • Freight Services Received by Swift - Transportation services received from Central Freight represent LTL freight services rendered to haul parts and equipment to Company shop locations. • Other Services Provided by Swift - Other services provided by the Company to the identified related parties include equipment sales and miscellaneous services. • Other Services Received by Swift - Executive air transport, fuel storage, event fees, equipment purchases, miscellaneous repair services, and certain third-party payroll and employee benefits administration services from the identified related parties are included in other services received by the Company. Transactions with and amounts owed to and from these affiliated entities were de minimis during the period after September 8, 2017 through September 30, 2017.

Recently Issued Accounting Pr32

Recently Issued Accounting Pronouncements, Not Yet Adopted (Policies)	9 Months Ended
	Sep. 30, 2017
Accounting Changes and Error Corrections [Abstract]
Basis of Presentation	We accounted for the 2017 Merger using the acquisition method of accounting in accordance with Topic 805, Business Combinations . GAAP requires that either Knight or Swift is designated as the acquirer for accounting and financial reporting purposes (“Accounting Acquirer”). Based on the evidence available, Knight was designated as the Accounting Acquirer. In identifying Knight as the Accounting Acquirer, we took into account the structure of the 2017 Merger, the composition of the combined company’s board of directors and the designation of certain senior management positions of the combined company, among other factors. Accordingly, the historical financial statements of Knight are the historical financial statements of the combined company. As such, information included within our condensed consolidated (unaudited) statements of income, comprehensive income and cash flows and their respective footnotes include the results of Swift from and after September 8, 2017 (the date of the closing of the 2017 Merger) to September 30, 2017. See Note 5 for the description of the purchase price allocation.
New Accounting Pronouncements, Not Yet Adopted	Recently Adopted Accounting Pronouncement — During the fourth quarter of 2016, Knight early adopted Accounting Standards Update No. 2016-09, Compensation - Stock Compensation (Topic 718): Improvement to Employee Share-Based Payment Accounting (ASU 2016-09). The standard requires us to reflect any adoption adjustments as of the beginning of the annual period that includes the interim period of adoption. As such, our condensed consolidated statements of income, statements of comprehensive income and statements of cash flows for the quarter ended and year-to-date September 30, 2016 , have been recast to include the impact of ASU 2016-09 adoption. See "Note 1-Significant Accounting Policies" in the notes to Knight's consolidated financial statements in Knight's Annual Report on Form 10-K for the fiscal year ended December 31, 2016 for detailed adoption information. Other Presentation Changes — Beginning in 2017 , we made the following changes in presentation: • Equipment sales receivables are separately presented within "Total current assets" in the condensed consolidated unaudited balance sheets. The prior period presentation has been retrospectively adjusted to reclassify the amount out of "Trade receivables, net of allowance for doubtful accounts" and into the new line item "Equipment sales receivable." The change in presentation has no net impact on "Total current assets." • Rental expenses related to revenue equipment are separately presented within "Total operating expenses" in the condensed consolidated statements of income. The prior period presentation has been retrospectively adjusted to reclassify the amount out of "Miscellaneous operating expenses" and into the new line item "Rental expense." The change in presentation has no impact on "Total operating expenses." • Excess tax benefits within the condensed consolidated statement of cash flows should be classified along with other income tax cash flows as an operating activity. Application is permitted to be prospective or retrospective. GAAP previously required classification within cash flows from financing activities. We retrospectively adjusted the year-to-date September 30, 2016 condensed consolidated statement of cash flows to align with the current period presentation by increasing cash flows from operating activities by $1.1 million and correspondingly decreasing cash flows from financing activities by $1.1 million , reflecting the amount of excess tax benefits previously presented for that period. Recently Issued Accounting Pronouncements, Not Yet Adopted Date Issued Reference Description Expected Adoption Date and Method Financial Statement Impact January 2017 2014-04: Intangibles – Goodwill and Other (Topic 350) – Simplifying the Test for Goodwill Impairment This update simplifies how an entity is required to test goodwill for impairment. Under the new guidance, annual or interim goodwill impairment testing will be performed by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment loss for the amount by which the carrying amount exceeds the reporting unit’s fair value. Any impairment loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. January 2020 Currently under evaluation November 2016 2016-18: Statement of Cash Flows (Topic 230) – Restricted Cash This update requires companies to include amounts generally described as restricted cash and restricted cash equivalents in cash and cash equivalents when reconciling beginning-of-period and end-of-period total amounts shown on the statement of cash flows. January 2018 Currently under evaluation August 2016 2016-15: Statement of Cash Flows (Topic 203) – Classification of Certain Cash Receipts and Cash Payments This update addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice. January 2018 Currently under evaluation May 2016 2016-12: Revenue from Contracts with Customers (Topic 606) – Narrow-scope Improvements and Practical Expedients The amendments in this ASU clarify certain aspects regarding the collectibility criterion, sales taxes collected from customers, noncash consideration, contract modifications, and completed contracts at transition. It additionally clarifies that retrospective application only requires disclosure of the accounting change effect on prior periods presented, not on the period of adoption. January 2018, Modified retrospective Currently under evaluation (1) April 2016 2016-10: Revenue from Contracts with Customers (Topic 606) – Identifying Performance Obligations and Licensing The amendments in this ASU clarify the following two aspects of Topic 606: identifying performance obligations and the licensing implementation guidance, while retaining the related principles for those areas. The amendments do not change the core principle of the guidance. January 2018, Modified retrospective Currently under evaluation (1) March 2016 2016-08: Revenue from Contracts with Customers (Topic 606) – Principal versus Agent Considerations (Reporting Revenue Gross versus Net) The amendments in this ASU are intended to improve the operability and understandability of the implementation guidance on principal versus agent considerations, but do not change the core principle of the guidance. January 2018, Modified retrospective Currently under evaluation (1) Date Issued Reference Description Expected Adoption Date and Method Financial Statement Impact February 2016 2016-02: Leases (Topic 842) This update seeks to increase the transparency and comparability among entities by requiring public entities to recognize lease assets and lease liabilities on the balance sheet and disclose key information about leasing arrangements. To satisfy the standard’s objective, a lessee will recognize a right-of-use asset representing its right to use the underlying asset for the lease term and a lease liability for the obligation to make lease payments. Both the right-of-use asset and lease liability will initially be measured at the present value of the lease payments, with subsequent measurement dependent on the classification of the lease as either a finance or an operating lease. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. If a lessee makes this election, it should recognize lease expense for such leases generally on a straight-line basis over the lease term. Accounting by lessors will remain mostly unchanged from current GAAP. January 2019, Modified retrospective Currently under evaluation; expected to be material, but not yet quantifiable. January 2016 2016-01: Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities The update (i) requires equity investments (except those accounted for under the equity method or that are consolidated) to be measured at fair value with changes in fair value recognized in net income; (ii) simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; (iii) eliminates the requirement for an entity to disclose the methods and significant assumptions used to estimate the fair value of financial instruments measured at amortized cost; (iv) requires an entity to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; and (v) requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or in the accompanying notes to the financial statements. January 2018, retrospective Currently under evaluation August 2015 2015-14: Revenue from Contracts with Customers (Topic 606) – Deferral of the Effective Date This ASU deferred the effective date of ASU 2014-09 (Topic 606) to annual reporting periods beginning after December 15, 2017. January 2018, Modified retrospective Currently under evaluation (1) ____________ (1) We have established an ASC 606 implementation team, which includes support from external experts, to evaluate and implement the standard. The diagnostic phase of assessing the financial and business impacts of implementing the standard is well underway and includes identifying revenue sources within the our lines of business, reviewing a sample of contracts, analyzing the impact on our systems, and developing a preliminary assessment. Based upon the procedures performed in the diagnostic phase, we anticipates that the following key considerations will impact the our accounting and reporting under the new standard: • identification of what constitutes a contract in the our business practices, • variability in individual contracts, such as customer-specific terms that may vary from the master agreement, • principal versus agent determinations, • timing of revenue recognition (for example, point-in-time versus over time and/or accelerated versus deferred), • single versus multiple performance obligations, including the timing of when such performance obligations are satisfied • new/changed estimates and management judgments (for example, system estimation of in-transit accruals versus manual estimation), • disaggregation of revenue by category within segments, and • others. We expect that there will also be changes in sales, contracting, accounting, reporting, tax, debt covenants, and other business processes, policies, and controls, as a result of implementing the standard. The 2017 Merger is also affecting the timing and other components of the implementation process. Based on the information currently available from the diagnostic phase, we cannot yet determine the quantitative impact on the financial statements. We expect changes related to the timing of revenue recognition between reportable periods, as well as changes in the requirements for accounting policy and other new disclosures. As the diagnostic phase is being finalized, we are proceeding to design and develop solutions in preparation for the implementation phase of the standard. Since we are continuing to evaluate the impact of the standard, disclosures around these preliminary assessments are subject to change.
Restricted Cash	Restricted Cash — Our wholly-owned captive insurance companies, Red Rock and Mohave, maintain certain operating bank accounts, working trust accounts, and investment accounts. The cash and short-term investments within the accounts are restricted by insurance regulations to fund the insurance claim losses to be paid by the captive insurance companies. Therefore, these cash and short-term investments are classified as "Cash and cash equivalents - restricted" in the condensed consolidated balance sheets.
Restricted investments	Restricted Investments -— Our investments are restricted by insurance regulations to fund the insurance claim losses to be paid by the captive insurance companies. The Company accounts for its investments in accordance with ASC 320, Investments - Debt and Equity Securities . Management determines the appropriate classification of its investments in debt securities at the time of purchase and re-evaluates the determination on a quarterly basis. As of September 30, 2017, all of our investments in fixed-maturity securities were classified as held-to-maturity, as we have the positive intent and ability to hold these securities to maturity. Held-to-maturity securities are carried at amortized cost. The amortized cost of debt securities is adjusted using the effective interest rate method for amortization of premiums and accretion of discounts. Amortization and accretion are reported in "Other income, net" in the condensed consolidated statement of income (unaudited). Management periodically evaluates restricted investments for impairment. The assessment of whether impairments have occurred is based on management's case-by-case evaluation of the underlying reasons for the decline in estimated fair value. Management accounts for other-than-temporary impairments of debt securities in accordance with ASC 320, Investments - Debt and Equity Securities . This guidance requires the Company to evaluate whether it intends to sell an impaired debt security or whether it is more likely than not that it will be required to sell an impaired debt security before recovery of the amortized cost basis. If either of these criteria are met, an impairment loss equal to the difference between the debt security's amortized cost and its estimated fair value is recognized in earnings. For impaired debt securities that do not meet these criteria, we determine if a credit loss exists with respect to the impaired security. If a credit loss exists, the credit loss component of the impairment (i.e., the difference between the security's amortized cost and the present value of projected future cash flows expected to be collected) is recognized in earnings and the remaining portion of the impairment is recognized as a component of accumulated other comprehensive income.
Operating leases	Operating Leases — In accordance with ASC 840, Leases , property and equipment held under operating leases, and liabilities related thereto, are off-balance sheet. All expenses related to operating leases are reflected in our condensed consolidated statements of income (unaudited) in "Rental expense." At the inception of a lease, management judgment is involved in classification as an operating or capital lease, as well as determination of useful lives and estimation of residual values of the related equipment. Future minimum lease payments used in determining lease classification represent the minimum rental payments called for over the lease term, inclusive of residual value guarantees (if applicable) and amounts that would be required to be paid, if any, by the Company upon default for leases containing subjective acceleration or cross default clauses. We do not currently guarantee residual values under our operating lease agreements for revenue equipment. To the extent we believe any manufacturer will refuse or be unable to meet its obligation, we recognize additional rental expense to the extent we believe the fair market value at the lease termination will be less than our obligation to the lessor. We believe that proceeds from the sale of equipment under operating leases would exceed the payment obligation on substantially all operating leases.

Recently Issued Accounting Pr33

Recently Issued Accounting Pronouncements, Not Yet Adopted (Tables)	9 Months Ended
	Sep. 30, 2017
Accounting Changes and Error Corrections [Abstract]
Description of New Accounting Pronouncements Not yet Adopted	Date Issued Reference Description Expected Adoption Date and Method Financial Statement Impact January 2017 2014-04: Intangibles – Goodwill and Other (Topic 350) – Simplifying the Test for Goodwill Impairment This update simplifies how an entity is required to test goodwill for impairment. Under the new guidance, annual or interim goodwill impairment testing will be performed by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment loss for the amount by which the carrying amount exceeds the reporting unit’s fair value. Any impairment loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. January 2020 Currently under evaluation November 2016 2016-18: Statement of Cash Flows (Topic 230) – Restricted Cash This update requires companies to include amounts generally described as restricted cash and restricted cash equivalents in cash and cash equivalents when reconciling beginning-of-period and end-of-period total amounts shown on the statement of cash flows. January 2018 Currently under evaluation August 2016 2016-15: Statement of Cash Flows (Topic 203) – Classification of Certain Cash Receipts and Cash Payments This update addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice. January 2018 Currently under evaluation May 2016 2016-12: Revenue from Contracts with Customers (Topic 606) – Narrow-scope Improvements and Practical Expedients The amendments in this ASU clarify certain aspects regarding the collectibility criterion, sales taxes collected from customers, noncash consideration, contract modifications, and completed contracts at transition. It additionally clarifies that retrospective application only requires disclosure of the accounting change effect on prior periods presented, not on the period of adoption. January 2018, Modified retrospective Currently under evaluation (1) April 2016 2016-10: Revenue from Contracts with Customers (Topic 606) – Identifying Performance Obligations and Licensing The amendments in this ASU clarify the following two aspects of Topic 606: identifying performance obligations and the licensing implementation guidance, while retaining the related principles for those areas. The amendments do not change the core principle of the guidance. January 2018, Modified retrospective Currently under evaluation (1) March 2016 2016-08: Revenue from Contracts with Customers (Topic 606) – Principal versus Agent Considerations (Reporting Revenue Gross versus Net) The amendments in this ASU are intended to improve the operability and understandability of the implementation guidance on principal versus agent considerations, but do not change the core principle of the guidance. January 2018, Modified retrospective Currently under evaluation (1) Date Issued Reference Description Expected Adoption Date and Method Financial Statement Impact February 2016 2016-02: Leases (Topic 842) This update seeks to increase the transparency and comparability among entities by requiring public entities to recognize lease assets and lease liabilities on the balance sheet and disclose key information about leasing arrangements. To satisfy the standard’s objective, a lessee will recognize a right-of-use asset representing its right to use the underlying asset for the lease term and a lease liability for the obligation to make lease payments. Both the right-of-use asset and lease liability will initially be measured at the present value of the lease payments, with subsequent measurement dependent on the classification of the lease as either a finance or an operating lease. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. If a lessee makes this election, it should recognize lease expense for such leases generally on a straight-line basis over the lease term. Accounting by lessors will remain mostly unchanged from current GAAP. January 2019, Modified retrospective Currently under evaluation; expected to be material, but not yet quantifiable. January 2016 2016-01: Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities The update (i) requires equity investments (except those accounted for under the equity method or that are consolidated) to be measured at fair value with changes in fair value recognized in net income; (ii) simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; (iii) eliminates the requirement for an entity to disclose the methods and significant assumptions used to estimate the fair value of financial instruments measured at amortized cost; (iv) requires an entity to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; and (v) requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or in the accompanying notes to the financial statements. January 2018, retrospective Currently under evaluation August 2015 2015-14: Revenue from Contracts with Customers (Topic 606) – Deferral of the Effective Date This ASU deferred the effective date of ASU 2014-09 (Topic 606) to annual reporting periods beginning after December 15, 2017. January 2018, Modified retrospective Currently under evaluation (1) ____________ (1) We have established an ASC 606 implementation team, which includes support from external experts, to evaluate and implement the standard. The diagnostic phase of assessing the financial and business impacts of implementing the standard is well underway and includes identifying revenue sources within the our lines of business, reviewing a sample of contracts, analyzing the impact on our systems, and developing a preliminary assessment. Based upon the procedures performed in the diagnostic phase, we anticipates that the following key considerations will impact the our accounting and reporting under the new standard: • identification of what constitutes a contract in the our business practices, • variability in individual contracts, such as customer-specific terms that may vary from the master agreement, • principal versus agent determinations, • timing of revenue recognition (for example, point-in-time versus over time and/or accelerated versus deferred), • single versus multiple performance obligations, including the timing of when such performance obligations are satisfied • new/changed estimates and management judgments (for example, system estimation of in-transit accruals versus manual estimation), • disaggregation of revenue by category within segments, and • others. We expect that there will also be changes in sales, contracting, accounting, reporting, tax, debt covenants, and other business processes, policies, and controls, as a result of implementing the standard. The 2017 Merger is also affecting the timing and other components of the implementation process. Based on the information currently available from the diagnostic phase, we cannot yet determine the quantitative impact on the financial statements. We expect changes related to the timing of revenue recognition between reportable periods, as well as changes in the requirements for accounting policy and other new disclosures. As the diagnostic phase is being finalized, we are proceeding to design and develop solutions in preparation for the implementation phase of the standard. Since we are continuing to evaluate the impact of the standard, disclosures around these preliminary assessments are subject to change.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Calculation Of Basic And Diluted Earnings Per Share Attributable To Stockholders	The following table reconciles the basic and diluted earnings per share computation for the quarter ended and year-to-date September 30, 2017 and 2016 : Quarter Ended September 30, Year-to-Date September 30, 2017 2016 2017 2016 (In thousands, except per share data) Weighted-average common shares outstanding – basic 102,846 80,040 87,978 80,284 Dilutive effect of stock options and unvested restricted stock units (1) 906 909 869 828 Weighted-average common shares outstanding – diluted 103,752 80,949 88,847 81,112 Net income attributable to Knight-Swift (2) $ 3,881 $ 23,767 $ 36,728 $ 71,702 Basic earnings per share $ 0.04 $ 0.30 $ 0.42 $ 0.89 Diluted earnings per share $ 0.04 $ 0.29 $ 0.41 $ 0.88 ____________ (1) Shares were excluded from the dilutive-effect calculation because the outstanding options' exercise prices were greater than the average market price of Knight's Common Stock for the 2016 periods and the Class A Common Stock for the 2017 periods. Quarter Ended September 30, Year-to-Date September 30, 2017 2016 2017 2016 (In thousands) Number of anti-dilutive shares 654 937 488 1,072 (2) Knight early adopted ASU 2016-09, Improvements to Employee Share-Based Payment Accounting during the fourth quarter of 2016. The adoption of this standard resulted in the recognition of $1.8 million of excess tax benefits to the income tax provision for the year ended December 31, 2016. Net income and shares outstanding data for the quarter ended and year-to-date September 30, 2016 are presented as if the ASU was adopted at the beginning of 2016.

Information by Segment and Ge35

Information by Segment and Geography (Tables)	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Summary Of Financial Information By Segments	The following tables present our financial information by segment: Quarter Ended September 30, Year-to-Date September 30, 2017 2016 2017 2016 Amount % of Total Amount % of Total Amount % of Total Amount % of Total Total revenue: (Dollars in thousands) Knight Trucking $ 222,307 42.6 % $ 228,590 81.5 % $ 661,320 62.0 % $ 672,969 81.2 % Logistics 57,904 11.1 53,643 19.1 166,959 15.7 163,955 19.8 Swift Truckload 115,899 22.2 — — 115,899 10.9 — — Dedicated 39,120 7.5 — — 39,120 3.7 — — Refrigerated 47,506 9.1 — — 47,506 4.5 — — Intermodal 24,046 4.6 — — 24,046 2.3 — — Subtotal 506,782 282,233 1,054,850 836,924 Swift Non-reportable segments 20,212 3.9 — — 20,212 1.9 — — Intersegment (5,386 ) (1.0 ) (1,703 ) (0.6 ) (9,029 ) (1.0 ) (7,988 ) (1.0 ) Consolidated $ 521,608 100.0 % $ 280,530 100.0 % $ 1,066,033 100.0 % $ 828,936 100.0 % Quarter Ended September 30, Year-to-Date September 30, 2017 2016 2017 2016 Amount % of Total Amount % of Total Amount % of Total Amount % of Total Operating income (loss): (Dollars in thousands) Knight Trucking $ 8,581 147.7 % $ 34,439 93.2 % $ 54,603 96.0 % $ 105,647 92.9 % Logistics 3,651 62.8 2,495 6.8 8,677 15.3 8,095 7.1 Swift Truckload 7,967 137.1 — — 7,967 14.0 — — Dedicated 2,949 50.7 — — 2,949 5.2 — — Refrigerated 427 7.3 — — 427 0.8 — — Intermodal 1,396 24.0 — — 1,396 2.5 — — Subtotal 24,971 36,934 76,019 113,742 Swift Non-reportable segments (19,160 ) (329.6 ) — — (19,160 ) (33.8 ) — — Consolidated operating income $ 5,811 100.0 % $ 36,934 100.0 % $ 56,859 100.0 % $ 113,742 100.0 % Quarter Ended September 30, Year-to-Date September 30, 2017 2016 2017 2016 Amount % of Total Amount % of Total Amount % of Total Amount % of Total Depreciation and amortization of property and equipment (Dollars in thousands) Knight Trucking $ 27,552 63.4 % $ 27,863 96.1 % $ 83,678 81.8 % $ 82,999 96.4 % Logistics 1,245 2.9 1,141 3.9 3,922 3.8 3,112 3.6 Swift Truckload 6,179 14.2 — — 6,179 6.0 — — Dedicated 2,861 6.6 — — 2,861 2.8 — — Refrigerated 2,147 4.9 — — 2,147 2.1 — — Intermodal 603 1.4 — — 603 0.6 — — Subtotal 40,587 29,004 99,390 86,111 Swift Non-reportable segments 2,890 6.6 — — 2,890 2.8 — — Consolidated depreciation and amortization of property and equipment $ 43,477 100.0 % $ 29,004 100.0 % $ 102,280 100.0 % $ 86,111 100.0 %

Purchase Price Allocation (Tabl

Purchase Price Allocation (Tables)	9 Months Ended
	Sep. 30, 2017
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition	The following table summarizes the total fair value consideration transferred (in thousands except per share data): Number of Swift shares outstanding at September 8, 2017 134,765 Swift share conversion ratio 0.72 Swift shares outstanding post-Reverse Split and immediately prior to the 2017 Merger 97,031 Closing price of Knight on September 8, 2017 $ 40.85 Fair value of equity portion of the 2017 Merger consideration $ 3,963,712 Fair Value of Swift equity awards and noncontrolling interest assumed 13,193 Total Fair value of consideration transferred $ 3,976,905
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following is a preliminary summary of the allocation of purchase consideration to the estimated fair value of Swift’s assets acquired and liabilities assumed in the 2017 Merger (in thousands): Fair value of the consideration transferred $ 3,976,905 Cash and cash equivalents $ 28,484 Restricted cash and fixed maturity securities 85,615 Trade and other receivables 411,767 Prepaid expenses 44,564 Other current assets 19,736 Property and equipment 1,522,123 Identifiable intangible assets 1,285,900 Other noncurrent assets 18,537 Total assets 3,416,726 Accounts payable (188,411 ) Accrued liabilities (232,280 ) Claims accruals (306,846 ) Long-term debt and capital lease obligations (894,681 ) Deferred tax liabilities (741,405 ) Other long-term liabilities (18,452 ) Total liabilities (2,382,075 ) Goodwill $ 2,942,254
Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Merger	Following are the details of the preliminary purchase price allocated to the identifiable intangible assets acquired: Estimated Life Estimated (years) (thousands) Customer relationships 10 - 20 years $ 817,200 Trade name indefinite 468,700 Total identifiable intangible assets $ 1,285,900
Summary of Pro Forma Revenue and Net Income	The following unaudited pro forma information combines the historical operations of Knight and Swift, giving effect to the 2017 Merger and related transactions as if they had been consummated on January 1, 2016, the beginning of the earliest period presented. Year-to-Date September 30, 2017 September 30, 2016 Total revenue $ 3,776,841 $ 3,821,839 Net income $ 83,727 $ 165,613 Diluted earnings per share $ 0.47 $ 0.92

Goodwill and Other Intangible37

Goodwill and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The changes in the carrying amounts of goodwill were as follows: September 30, 2017 (In thousands) Goodwill at beginning of period $ 47,031 Amortization relating to deferred tax assets (15 ) Goodwill related to 2017 Merger 2,942,254 Goodwill at end of period $ 2,989,270
Schedule of Intangible Assets, net	Other intangible asset balances were as follows: September 30, December 31, (In thousands) Customer Relationships and Non Compete: Gross carrying amount $ 820,900 $ 3,700 Accumulated amortization (4,029 ) (1,125 ) Customer relationships and non-compete, net $ 816,871 $ 2,575 Trade Name: Gross carrying amount 468,700 — Intangible assets, net $ 1,285,571 $ 2,575
Finite-lived Intangible Assets Amortization Expense	The following table presents amortization of intangible assets related to the 2017 Merger and intangible assets existing prior to the 2017 Merger: Quarter Ended September 30, Year-to-Date September 30, 2017 2016 2017 2016 (In thousands) Amortization of intangible assets related to the 2017 Merger $ 2,529 $ — $ 2,529 $ — Amortization related to intangible assets existing prior to the 2017 Merger 125 125 375 375 Amortization of intangibles $ 2,654 $ 125 $ 2,904 $ 375

Investments and Related Commi38

Investments and Related Commitments (Tables)	9 Months Ended
	Sep. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Summary of Investments	Investment balances included in “Other long-term assets, restricted cash and investments” on our accompanying condensed consolidated unaudited balance sheets were as follows: September 30, 2017 December 31, 2016 (in thousands) Investment in Transportation Resource Partners (TRP) $ 211 $ 214 Investment in Transportation Resource Partners III (TRP III) 2,146 5,882 Investment in Transportation Resource Partners IV (TRP IV) 2,580 1,882 Investment in Transportation Resource Partners CoInvest Partners, (NTI) I, LP (TRP Coinvestment) 8,625 10,000 Investment in Transportation Resource Partners CoInvest Partners, (QLS) I, LP (TRP Coinvestment QLS) 7,145 9,735 $ 20,707 $ 27,713

Marketable Equity Securities (T

Marketable Equity Securities (Tables)	9 Months Ended
	Sep. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Schedule of Realized Gains	The following table shows our realized gains during the quarter ended and year-to-date September 30, 2017 and 2016 , on certain securities that were classified as available-for-sale: Quarter Ended September 30, Year-to-Date September 30, 2017 2016 2017 2016 Realized Gains: (In thousands) Sales proceeds $ — $ 2,220 $ — $ 7,403 Cost of securities sold — 796 — 2,909 Realized gain $ — $ 1,424 $ — $ 4,494 Realized gain, net of taxes $ — $ 878 $ — $ 2,771

Restricted Investments (Tables)

Restricted Investments (Tables)	9 Months Ended
	Sep. 30, 2017
Schedule of Investments [Abstract]
Schedule of Restricted Investments	The following table presents the cost or amortized cost, gross unrealized gains and temporary losses, and estimated fair value of our restricted investments: September 30, 2017 Gross Unrealized Cost or Amortized Gains Temporary Estimated Fair Value (In thousands) United States corporate securities $ 16,033 $ — $ (5 ) $ 16,028 Municipal bonds 4,990 1 (2 ) 4,989 Negotiable certificate of deposits 1,280 — — 1,280 Restricted investments, held to maturity $ 22,303 $ 1 $ (7 ) $ 22,297

Notes Receivable (Tables)

Notes Receivable (Tables)	9 Months Ended
	Sep. 30, 2017
Receivables [Abstract]
Summary of Current and Long-Term Balance of Notes Receivable	Notes receivable are included in "Notes receivable, net" and "Notes receivable, long-term" in the condensed consolidated balance sheets and were comprised of: September 30, 2017 December 31, 2016 (In thousands) Notes receivable from independent contractors $ 10,910 $ 1,039 Notes receivable from third parties 8,292 2,808 Gross notes receivable 19,202 3,847 Allowance for doubtful notes receivable (559 ) (240 ) Total notes receivable, net of allowance $ 18,643 $ 3,607 Current portion, net of allowance 5,984 560 Long-term portion $ 12,659 $ 3,047

Debt and Financing (Tables)

Debt and Financing (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	The following table presents the key terms of the 2017 Agreement: Description Term Loan Revolver (2) (Dollars in thousands) Maximum borrowing capacity $400,000 $800,000 Final maturity date October 2, 2020 October 3, 2022 Interest rate base LIBOR LIBOR Interest rate minimum margin (1) 0.875% 0.875% Interest rate maximum margin (1) 1.50% 1.50% Minimum principal payment – amount $— $— Minimum principal payment – frequency Once Once Minimum principal payment – commencement date October 2, 2020 October 3, 2022 ____________ (1) The interest rate margin for the Term Loan and the Revolver is based on our consolidated leverage ratio. As of September 30, 2017 , interest accrued at 2.36% on the Term Loan and 2.36% on the Revolver. (2) The commitment fee for the unused portion of the Revolver is based on our consolidated leverage ratio and ranges from 0.07% to 0.20% . As of September 30, 2017 , commitment fees on the unused portion of the Revolver accrued at 0.13% and outstanding letter of credit fees accrued at 1.13% .
Schedule of Debt Balances by Instrument	Other than our accounts receivable securitization, as discussed in Note 14 , and our outstanding capital lease obligations as discussed in Note 17 , our long-term debt consisted of the following: September 30, December 31, (In thousands) Term Loan, due October 2020, net of $704 deferred loan costs (1) $ 399,296 $ — Other 453 — Long-term debt 399,749 — Less: current portion of long-term debt (30 ) — Long-term debt, less current portion $ 399,719 $ — September 30, December 31, (In thousands) Long-term debt $ 399,749 $ — Knight Revolver, due August 2019 (1) (2) — 18,000 Knight-Swift Revolver, due October 2022 (1) (3) 85,000 — Long-term debt, including revolving line of credit $ 484,749 $ 18,000 ____________ (1) Refer to Note 21 for information regarding the fair value of long-term debt. (2) Knight also had outstanding letters of credit under the Knight Revolver of $31.3 million at December 31, 2016 , issued to various regulatory authorities and insurance carriers in connection with Knight's self-insurance programs. (3) The Company also had outstanding letters of credit under the Revolver of $124.8 million at September 30, 2017

Deferred Loan Costs (Tables)

Deferred Loan Costs (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Issuance Costs, Net [Abstract]
Debt Issuance Costs	The following table presents the classification of deferred loan costs in our condensed consolidated balance sheets: September 30, December 31, (In thousands) ASSETS: Other assets $ 1,608 $ — LIABILITIES: Long-term debt, less current portion 704 — Total deferred loan costs $ 2,312 $ —

Leases Leases (Tables)

Leases Leases (Tables)	9 Months Ended
	Sep. 30, 2017
Leases [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	As of September 30, 2017 , annual future minimum lease payments for all noncancelable leases were: Operating Capital (In thousands) 2017 $ 55,912 $ 16,198 2018 177,778 51,008 2019 122,607 61,281 2020 74,832 14,984 2021 39,130 30,848 Thereafter 58,984 29,463 Future minimum lease payments $ 529,243 $ 203,782 Less: amounts representing interest (13,681 ) Present value of minimum lease payments 190,101 Less: current portion (54,561 ) Capital lease obligations, less current portion $ 135,540
Schedule of Future Minimum Lease Payments for Capital Leases	As of September 30, 2017 , annual future minimum lease payments for all noncancelable leases were: Operating Capital (In thousands) 2017 $ 55,912 $ 16,198 2018 177,778 51,008 2019 122,607 61,281 2020 74,832 14,984 2021 39,130 30,848 Thereafter 58,984 29,463 Future minimum lease payments $ 529,243 $ 203,782 Less: amounts representing interest (13,681 ) Present value of minimum lease payments 190,101 Less: current portion (54,561 ) Capital lease obligations, less current portion $ 135,540
Schedule Of Future Minimum Lease Payments Receivable	Annual future minimum lease payments receivable under operating leases for the periods noted below were: (In thousands) 2017 $ 25,061 2018 69,208 2019 35,119 2020 18,383 2021 5,196 Thereafter — Future minimum lease payments receivable $ 152,967

Contingencies and Legal Proce45

Contingencies and Legal Proceedings (Tables)	9 Months Ended
	Sep. 30, 2017
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 drivers: that Swift 1) failed to pay minimum wage; 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. 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 Recent Developments and Current Status On August 29, 2017, the Parties in the Slack case reached a settlement. On October 10, 2017, the court granted a motion for preliminary approval of the settlement. The court set a date of January 29, 2018 for the fairness hearing. The likelihood that a loss has been incurred in the Slack matter is probable. ___________ (1) Individually and on behalf of all others similarly situated. INDEPENDENT CONTRTACTOR MATTERS Ninth Circuit Independent Contractor Misclassification Class Action The putative class alleges that Swift misclassified independent contractors as independent contractors in violation of the FLSA and various state laws, and that such independent contractors should be considered employees. 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. 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 January 2017, the district court issued an order finding that the plaintiffs had signed contracts of employment and thus the case could properly proceed in court. Swift has appealed this decision to the Ninth Circuit and the parties have discussed settlement. Based on the above, the likelihood that a loss has been incurred is probable. INDEPENDENT CONTRTACTOR MATTERS Utah Collective and Individual Arbitration The plaintiffs allege that the Central Parties (defined below) misclassified independent contractor drivers as independent contractors and were therefore liable to these drivers for minimum wages and other employee benefits under the FLSA. The complaint also alleges a federal forced labor claim under U.S.C. §1589 and §1595, as well as fraud and other state-law claims. Plaintiff(s) Defendant(s) Date instituted Court or agency currently pending in Gabriel Ciluffo, Kevin Shire, and Bryan Ratterree (1) Central Refrigerated Service, Inc., Central Leasing, Inc., Jon Isaacson, and Jerry Moyes (the "Central Parties"), as well as Swift Transportation Company June 1, 2012 American Arbitration Association Recent Developments and Current Status In October 2016, the arbitrator ruled that approximately 1,300 Central Refrigerated Service, Inc. drivers were improperly classified as independent contractors, when they should have been classified and compensated as employees. The arbitrator ruled that damages could ultimately be assessed in a collective proceeding and denied Swift’s motion to decertify the collective proceeding. On April 14, 2017, the parties reached a settlement of the matter. The parties are currently pursuing court approval of that settlement. The likelihood that a loss has been incurred is probable. ___________ (1) Individually and on behalf of all others similarly situated.

Share Repurchase Programs (Tabl

Share Repurchase Programs (Tables)	9 Months Ended
	Sep. 30, 2017
Class of Stock Disclosures [Abstract]
Share Repurchases	The following table presents repurchases of Knight Common Stock under Knight Repurchase Plan for the quarter ended and year-to-date September 30, 2016 : Quarter Ended September 30, Year-to-Date September 30, Share Repurchase Program 2016 2016 Authorized Amount Board Approval Date Shares Amount Shares Amount (In thousands) (In thousands) 10,000 May 19, 2011 100 $ 3,300 1,600 $ 39,900

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value by Balance Sheet Grouping	The following table presents the carrying amounts and estimated fair values of our financial instruments: September 30, 2017 December 31, 2016 Carrying Estimated Carrying Estimated (In thousands) Financial Assets: Restricted investments (1) $ 22,303 $ 22,297 $ — $ — Money market funds (2) 1,597 1,597 1,385 1,385 Debt securities - municipal securities (2) 1,728 1,728 1,903 1,903 Financial Liabilities: Term Loan, due October 2020 (3) 399,296 400,000 — — 2015 RSA, due January 2019 285,000 285,000 — — Knight Revolver, due August 2019 — — 18,000 18,000 Revolver, due October 2022 85,000 85,000 — — ____________ The carrying amounts of the financial instruments shown in the table are included in the condensed consolidated balance sheets, as follows: (1) Restricted investments are included in "Restricted investments, held to maturity, amortized cost." (2) Items included within "Other long-term assets, restricted cash and investments." (3) Carrying value is net of $0.7 million deferred loan costs as of September 30, 2017 .
Fair Value Measurements, Recurring Basis	The following table depicts the level in the fair value of assets measured on a recurring basis as of September 30, 2017 and December 31, 2016 : Fair Value Measurements at Reporting Date Using: Estimated Level 1 Inputs Level 2 Inputs Level 3 Inputs (In thousands) As of September 30, 2017 Money market funds $ 1,597 $ 1,597 $ — $ — Debt securities - municipal securities 1,728 — 1,728 — As of December 31, 2016 Money market funds $ 1,385 $ 1,385 $ — $ — Debt securities - municipal securities 1,903 — 1,903 —
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 September 30, 2017 : Fair Value Measurements at Reporting Date Using: Estimated Level 1 Inputs Level 2 Inputs Level 3 Inputs Total Gains (Losses) (In thousands) As of September 30, 2017 Software (1) $ — $ — $ — $ — $ (16,746 ) ____________ (1) During the quarter ended September 30, 2017 , we terminated the implementation of the Swift ERP system. This resulted in a pre-tax impairment loss of $16.7 million , which was recorded in "Impairments" within operating income in the condensed consolidated unaudited statements of income.

Stock Compensation Expense (Tab

Stock Compensation Expense (Tables)	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs	The following table shows the stock compensation expense categorized by unit: Quarter Ended September 30, Year-to-Date September 30, 2017 2016 2017 2016 (In thousands) Stock compensation expense for options, net of forfeitures $ 480 $ 434 $ 1,309 $ 1,318 Stock compensation expense for restricted stock units and performance restricted stock units, net of forfeitures 1,340 112 2,084 1,808 Total stock compensation expense, net of forfeitures $ 1,820 $ 546 $ 3,393 $ 3,126
Schedule of Share-based Compensation, Stock Options, Activity	The following table is a summary of the option award activity under our equity compensation plans: Option Totals Weighted Average Exercise Outstanding as of December 31, 2016 1,737,400 $ 23.19 Granted 497,421 33.35 Assumed Swift stock options 528,466 21.93 Exercised (515,012 ) 21.83 Forfeited (169,616 ) 27.35 Outstanding as of September 30, 2017 2,078,659 $ 25.30
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	Listed below are the weighted-average assumptions used for the fair value computation: Year-to-Date September 30, 2017 2016 Dividend yield (1) 0.72 % 0.99 % Expected volatility (2) 27.95 % 27.91 % Risk-free interest rate (3) 1.49 % 0.90 % Expected term (4) 3.22 years 2.74 years Weighted-average fair value of options granted $ 6.78 $ 4.28 ____________ (1) Dividend yield - the dividend yield is based on our historical experience and future expectation of dividend payouts. (2) Expected volatility - we analyzed the volatility of our stock using historical data. (3) Risk-free interest rate - the risk-free interest rate assumption is based on U.S. Treasury securities at a constant maturity with a maturity period that most closely resembles the expected term of the stock option award. (4) Expected term - the expected term of employee stock options represents the weighted-average period the stock options are expected to remain outstanding and has been determined based on an analysis of historical exercise behavior.
Schedule of Nonvested Restricted Stock Units Activity	The following table is a summary of the restricted stock unit award activity under our equity compensation plans for year-to-date September 30, 2017 : Number of Restricted Stock Unit Awards Weighted Average Grant Date Fair Value Outstanding as of December 31, 2016 686,786 $ 16.46 Granted 124,145 33.35 Assumed Swift restricted stock units 168,488 40.85 Vested (126,871 ) 16.77 Forfeited (35,593 ) 21.32 Outstanding as of September 30, 2017 816,955 $ 22.53
Share-based Compensation, Performance Shares Award Unvested Activity	A summary of the PRSU activity under our equity compensation plans for year-to-date September 30, 2017 is presented below: Number of Performance Restricted Stock Unit Awards Weighted Average Grant Date Fair Value Unvested as of December 31, 2016 508,478 $ 25.60 Granted — — Assumed Swift PRSUs 56,817 $ 40.85 Shares earned above target 21,117 — 23.85 Vested (1) (519,483 ) $ 25.53 Cancelled (10,112 ) 25.40 Unvested as of September 30, 2017 56,817 $ 40.85 ____________ (1) During year-to-date September 30, 2017 , 107,967 shares vested and paid out, 329,417 shares vested related to the 2015 and 2016 awards for which the performance measurement period ends December 31, 2017 with no pay out expected, and 82,099 shares vested for certain executive officers for which payout will be at a future date.
Schedule Of Share-based Payment Award Equity Instruments Other Than Stock Options Valuation Assumptions	Listed below are the weighted-average assumptions used for the fair value computation for PRSU's granted in 2016: Year-to-Date September 30, 2016 Dividend yield (1) 0.99 % Expected volatility (2) 27.95 % Average peer volatility (2) 34.37 % Average peer correlation coefficient (3) 0.60 Risk-free interest rate (4) 0.89 % Expected term (5) 2.84 Weighted-average fair value of PRSUs granted $ 23.89 ____________ (1) The dividend yield, used to project stock price to the end of the performance period, is based on our historical experience and future expectation of dividend payouts. Total shareholder return is determined assuming that dividends are reinvested in the issuing entity over the performance period, which is mathematically equivalent to utilizing a 0% dividend yield. (2) We (or peer company) estimated volatility using our (or their) historical share price performance over the remaining performance period as of the grant date. (3) The correlation coefficients are used to model the way in which each entity tends to move in relation to each other; the correlation assumptions were developed using the same stock price data as the volatility assumptions. (4) The risk-free interest rate assumption is based on U.S. Treasury securities at a constant maturity with a maturity period that most closely resembles the expected term of the performance award. (5) Since the Monte Carlo simulation valuation is an open form model that uses an expected life commensurate with the performance period, the expected life of the PRSUs was assumed to be the period from the grant date to the end of the performance period.

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2017
Related Party Transactions [Abstract]
Rollforward of accrued liability for consulting fees	The following schedule is a rollforward of the accrued liability for the consulting fees: September 30, (In thousands) Accrued consulting fees – Jerry Moyes, September 9, 2017 (1) $ 2,825 Additions to accrual — Less: payments — Accrued consulting fees – Jerry Moyes, September 30, 2017 (1) $ 2,825 ____________ (1) The balance is included in "Other liabilities" (noncurrent) and "Accrued liabilities" (current) in the condensed consolidated balance sheet (unaudited), based on the timing of the expected payments.

Introduction and Basis of Pre50

Introduction and Basis of Presentation - Merger (Details) - USD ($) $ / shares in Units, $ in Thousands	Sep. 08, 2017	Apr. 10, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Apr. 09, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Stock issued during period, shares, reverse stock splits (in shares)		0.72
Merger-related costs			$ 12,338	$ 0	$ 16,516	$ 0
Merger-related bonuses and accelerated stock compensation expense			154,390	82,688	316,844	250,732
Merger-related statutory filing fees			11,972	4,261	21,873	9,580
Driver retention expense			$ 127,434	$ 57,069	$ 244,358	$ 168,772
Knight Transportation Company [Member]
Business Acquisition [Line Items]
Common stock, par value (in dollars per share)							$ 0.01
Knight Swift [Member]
Business Acquisition [Line Items]
Stock issued during period, shares, reverse stock splits (in shares)		1
Common Class B [Member]
Business Acquisition [Line Items]
Common stock, par value (in dollars per share)			$ 0.01		$ 0.01			$ 0.01
Common Class B [Member] | Knight Transportation Company [Member]
Business Acquisition [Line Items]
Common stock, par value (in dollars per share)							0.01
Common Class A [Member]
Business Acquisition [Line Items]
Common stock, par value (in dollars per share)			$ 0.01		$ 0.01			$ 0.01
Common Class A [Member] | Knight Swift [Member]
Business Acquisition [Line Items]
Common stock, par value (in dollars per share)							$ 0.01
Knight-Swift Merger [Member]
Business Acquisition [Line Items]
Merger-related costs			$ 12,300		$ 16,500
Merger-related bonuses and accelerated stock compensation expense	$ 5,600
Merger-related statutory filing fees	900
Driver retention expense	$ 100

Introduction and Basis of Pre51

Introduction and Basis of Presentation - Description of Business (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)SegmentVehicle	Sep. 30, 2016USD ($)
Recently Issued Accounting Pronouncements [Line Items]
Net cash provided by operating activities | $	$ 132,323	$ 191,691
Net cash provided by financing activities | $	$ 18,673	(107,817)
Number of tractors in fleet	23,107
Number of company tractors	18,099
Number of owner-operator tractors	5,008
Number of trailers	75,715
Number of intermodal containers	9,122
Number of reportable segments | Segment	6
Accounting Standards Update 2016-09 [Member]
Recently Issued Accounting Pronouncements [Line Items]
Net cash provided by operating activities | $		1,100
Net cash provided by financing activities | $		$ (1,100)

Recently Issued Accounting Pr52

Recently Issued Accounting Pronouncements, Not Yet Adopted - (Details)	9 Months Ended
	Sep. 30, 2017
Accounting Standards Update 2014-04 [Member]
Recently Issued Accounting Pronouncements [Line Items]
Description	This update simplifies how an entity is required to test goodwill for impairment. Under the new guidance, annual or interim goodwill impairment testing will be performed by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment loss for the amount by which the carrying amount exceeds the reporting unit’s fair value. Any impairment loss recognized should not exceed the total amount of goodwill allocated to that reporting unit.
Expected Adoption Date and Method	January 2,020
Financial Statement Impact	Currently under evaluation
Accounting Standards Update 2016-18 [Member]
Recently Issued Accounting Pronouncements [Line Items]
Description	This update requires companies to include amounts generally described as restricted cash and restricted cash equivalents in cash and cash equivalents when reconciling beginning-of-period and end-of-period total amounts shown on the statement of cash flows.
Expected Adoption Date and Method	January 2,018
Financial Statement Impact	Currently under evaluation
Accounting Standards Update 2016-15 [Member]
Recently Issued Accounting Pronouncements [Line Items]
Description	This update addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice.
Expected Adoption Date and Method	January 2,018
Financial Statement Impact	Currently under evaluation
Accounting Standards Update 2016-12 [Member]
Recently Issued Accounting Pronouncements [Line Items]
Description	The amendments in this ASU clarify certain aspects regarding the collectibility criterion, sales taxes collected from customers, noncash consideration, contract modifications, and completed contracts at transition. It additionally clarifies that retrospective application only requires disclosure of the accounting change effect on prior periods presented, not on the period of adoption.
Expected Adoption Date and Method	January 2018, Modified retrospective
Financial Statement Impact	Currently under evaluation (1)	[1]
Accounting Standards Update 2016-10 [Member]
Recently Issued Accounting Pronouncements [Line Items]
Description	The amendments in this ASU clarify the following two aspects of Topic 606: identifying performance obligations and the licensing implementation guidance, while retaining the related principles for those areas. The amendments do not change the core principle of the guidance.
Expected Adoption Date and Method	January 2018, Modified retrospective
Financial Statement Impact	Currently under evaluation (1)	[1]
Accounting Standards Update 2016-08 [Member]
Recently Issued Accounting Pronouncements [Line Items]
Description	The amendments in this ASU are intended to improve the operability and understandability of the implementation guidance on principal versus agent considerations, but do not change the core principle of the guidance.
Expected Adoption Date and Method	January 2018, Modified retrospective
Financial Statement Impact	Currently under evaluation (1)	[1]
Accounting Standards Update 2016-02 [Member]
Recently Issued Accounting Pronouncements [Line Items]
Description	This update seeks to increase the transparency and comparability among entities by requiring public entities to recognize lease assets and lease liabilities on the balance sheet and disclose key information about leasing arrangements. To satisfy the standard’s objective, a lessee will recognize a right-of-use asset representing its right to use the underlying asset for the lease term and a lease liability for the obligation to make lease payments. Both the right-of-use asset and lease liability will initially be measured at the present value of the lease payments, with subsequent measurement dependent on the classification of the lease as either a finance or an operating lease. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. If a lessee makes this election, it should recognize lease expense for such leases generally on a straight-line basis over the lease term. Accounting by lessors will remain mostly unchanged from current GAAP.
Expected Adoption Date and Method	January 2019, Modified retrospective
Financial Statement Impact	Currently under evaluation; expected to be material, but not yet quantifiable.
Accounting Standards Update 2016-01 [Member]
Recently Issued Accounting Pronouncements [Line Items]
Description	The update (i) requires equity investments (except those accounted for under the equity method or that are consolidated) to be measured at fair value with changes in fair value recognized in net income; (ii) simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; (iii) eliminates the requirement for an entity to disclose the methods and significant assumptions used to estimate the fair value of financial instruments measured at amortized cost; (iv) requires an entity to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; and (v) requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or in the accompanying notes to the financial statements.
Expected Adoption Date and Method	January 2018, retrospective
Financial Statement Impact	Currently under evaluation
Accounting Standards Update 2015-04 [Member]
Recently Issued Accounting Pronouncements [Line Items]
Description	This ASU deferred the effective date of ASU 2014-09 (Topic 606) to annual reporting periods beginning after December 15, 2017.
Expected Adoption Date and Method	January 2018, Modified retrospective
Financial Statement Impact	Currently under evaluation (1)	[1]
[1]	(1)

Earnings Per Share - (Details)

Earnings Per Share - (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended		12 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Earnings Per Share [Abstract]
Weighted-average common shares outstanding - basic (in shares)		102,846	80,040	87,978	80,284
Dilutive effect of stock options and unvested restricted stock units (in shares)	[1]	906	909	869	828
Weighted-average common shares outstanding – diluted (in shares)		103,752	80,949	88,847	81,112
Net income attributable to Knight-Swift	[2]	$ 3,881	$ 23,767	$ 36,728	$ 71,702
Basic earnings per share (in dollars per share)		$ 0.04	$ 0.30	$ 0.42	$ 0.89
Diluted earnings per share (in dollars per share)		$ 0.04	$ 0.29	$ 0.41	$ 0.88
Number of anti-dilutive shares		654	937	488	1,072
Recently Issued Accounting Pronouncements [Line Items]
Income taxes (benefit) expense		$ (1,272)	$ 14,141	$ 17,786	$ 45,095
Accounting Standards Update 2016-09 [Member]
Recently Issued Accounting Pronouncements [Line Items]
Income taxes (benefit) expense						$ (1,800)
[1]	Shares were excluded from the dilutive-effect calculation because the outstanding options' exercise prices were greater than the average market price of Knight's Common Stock for the 2016 periods and the Class A Common Stock for the 2017 periods.
[2]	early adopted ASU 2016-09, Improvements to Employee Share-Based Payment Accounting during the fourth quarter of 2016. The adoption of this standard resulted in the recognition of $1.8 million of excess tax benefits to the income tax provision for the year ended December 31, 2016. Net income and shares outstanding data for the quarter ended and year-to-date September 30, 2016 are presented as if the ASU was adopted at the beginning of 2016.

Information by Segment and Ge54

Information by Segment and Geography - Segment Financial Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)operating_unitSegment	Sep. 30, 2016USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment			6
Description of all other segments			Swift Non-reportable Segments — The Swift non-reportable segments include Swift's logistics and freight brokerage services, as well as support services that Swift's subsidiaries provide to customers and independent contractors, including repair and maintenance shop services, equipment leasing and insurance. Certain legal settlements and reserves, and other corporate expenses are also included in the non-reportable segments.
Revenues	$ 521,608	$ 280,530	$ 1,066,033	$ 828,936
Percentage of revenue	100.00%	100.00%	100.00%	100.00%
Operating income (loss)	$ 5,811	$ 36,934	$ 56,859	$ 113,742
Percentage of operating income (loss)	100.00%	100.00%	100.00%	100.00%
Depreciation and amortization of property and equipment	$ 43,477	$ 29,004	$ 102,280	$ 86,111
Percentage of depreciation	100.00%	100.00%	100.00%	100.00%
Trucking [Member]
Segment Reporting Information [Line Items]
Number of Sub-Operating Units | operating_unit			3
Description of products and services			Knight Trucking — The Knight Trucking segment is comprised of three operating units (Dry Van, Refrigerated and Drayage).
Logistics [Member]
Segment Reporting Information [Line Items]
Number of Sub-Operating Units | operating_unit			2
Description of products and services			Knight Logistics — The Knight Logistics segment is comprised of two operating units (Brokerage and Intermodal). We also provide logistics freight management and other non-trucking services through our Knight Logistics business.
Truckload [Member]
Segment Reporting Information [Line Items]
Description of products and services			Swift Truckload — The Swift Truckload segment consists of one-way movements over irregular routes throughout the United States, Mexico, and Canada.
Dedicated [Member]
Segment Reporting Information [Line Items]
Description of products and services			Swift Dedicated — The Swift Dedicated segment devotes use of equipment to specific customers and offers tailored solutions under long-term contracts.
Refrigerated [Member]
Segment Reporting Information [Line Items]
Description of products and services			Swift Refrigerated — The Swift Refrigerated segment primarily consists of shipments for customers that require temperature-controlled trailers. These shipments include one-way movements over irregular routes, as well as dedicated truck operations.
Intermodal [Member]
Segment Reporting Information [Line Items]
Description of products and services			Swift Intermodal — The Swift Intermodal segment includes revenue generated by moving freight over the rail in Swift's containers and other trailing equipment, combined with revenue for drayage to transport loads between the railheads and customer locations.
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	$ 506,782	$ 282,233	$ 1,054,850	$ 836,924
Percentage of revenue
Operating income (loss)	$ 24,971	$ 36,934	$ 76,019	$ 113,742
Depreciation and amortization of property and equipment	40,587	29,004	99,390	86,111
Operating Segments [Member] | Trucking [Member]
Segment Reporting Information [Line Items]
Revenues	$ 222,307	$ 228,590	$ 661,320	$ 672,969
Percentage of revenue	42.60%	81.50%	62.00%	81.20%
Operating income (loss)	$ 8,581	$ 34,439	$ 54,603	$ 105,647
Percentage of operating income (loss)	147.70%	93.20%	96.00%	92.90%
Depreciation and amortization of property and equipment	$ 27,552	$ 27,863	$ 83,678	$ 82,999
Percentage of depreciation	63.40%	96.10%	81.80%	96.40%
Operating Segments [Member] | Logistics [Member]
Segment Reporting Information [Line Items]
Revenues	$ 57,904	$ 53,643	$ 166,959	$ 163,955
Percentage of revenue	11.10%	19.10%	15.70%	19.80%
Operating income (loss)	$ 3,651	$ 2,495	$ 8,677	$ 8,095
Percentage of operating income (loss)	62.80%	6.80%	15.30%	7.10%
Depreciation and amortization of property and equipment	$ 1,245	$ 1,141	$ 3,922	$ 3,112
Percentage of depreciation	2.90%	3.90%	3.80%	3.60%
Operating Segments [Member] | Truckload [Member]
Segment Reporting Information [Line Items]
Revenues	$ 115,899	$ 0	$ 115,899	$ 0
Percentage of revenue	22.20%	0.00%	10.90%	0.00%
Operating income (loss)	$ 7,967	$ 0	$ 7,967	$ 0
Percentage of operating income (loss)	137.10%	0.00%	14.00%	0.00%
Depreciation and amortization of property and equipment	$ 6,179	$ 0	$ 6,179	$ 0
Percentage of depreciation	14.20%	0.00%	6.00%	0.00%
Operating Segments [Member] | Dedicated [Member]
Segment Reporting Information [Line Items]
Revenues	$ 39,120	$ 0	$ 39,120	$ 0
Percentage of revenue	7.50%	0.00%	3.70%	0.00%
Operating income (loss)	$ 2,949	$ 0	$ 2,949	$ 0
Percentage of operating income (loss)	50.70%	0.00%	5.20%	0.00%
Depreciation and amortization of property and equipment	$ 2,861	$ 0	$ 2,861	$ 0
Percentage of depreciation	6.60%	0.00%	2.80%	0.00%
Operating Segments [Member] | Refrigerated [Member]
Segment Reporting Information [Line Items]
Revenues	$ 47,506	$ 0	$ 47,506	$ 0
Percentage of revenue	9.10%	0.00%	4.50%	0.00%
Operating income (loss)	$ 427	$ 0	$ 427	$ 0
Percentage of operating income (loss)	7.30%	0.00%	0.80%	0.00%
Depreciation and amortization of property and equipment	$ 2,147	$ 0	$ 2,147	$ 0
Percentage of depreciation	4.90%	0.00%	2.10%	0.00%
Operating Segments [Member] | Intermodal [Member]
Segment Reporting Information [Line Items]
Revenues	$ 24,046	$ 0	$ 24,046	$ 0
Percentage of revenue	4.60%	0.00%	2.30%	0.00%
Operating income (loss)	$ 1,396	$ 0	$ 1,396	$ 0
Percentage of operating income (loss)	24.00%	0.00%	2.50%	0.00%
Depreciation and amortization of property and equipment	$ 603	$ 0	$ 603	$ 0
Percentage of depreciation	1.40%	0.00%	0.60%	0.00%
Non-reportable segments [Member]
Segment Reporting Information [Line Items]
Revenues	$ 20,212	$ 0	$ 20,212	$ 0
Percentage of revenue	3.90%	0.00%	1.90%	0.00%
Operating income (loss)	$ (19,160)	$ 0	$ (19,160)	$ 0
Percentage of operating income (loss)	(329.60%)	0.00%	(33.80%)	0.00%
Depreciation and amortization of property and equipment	$ 2,890	$ 0	$ 2,890	$ 0
Percentage of depreciation	6.60%	0.00%	2.80%	0.00%
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues	$ (5,386)	$ (1,703)	$ (9,029)	$ (7,988)
Percentage of revenue	(1.00%)	(0.60%)	(1.00%)	(1.00%)

Information by Segment and Ge55

Information by Segment and Geography - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
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%

Purchase Price Allocation - Sum

Purchase Price Allocation - Summary of the Allocation of Purchase Consideration (Details) - USD ($) $ in Thousands	Sep. 08, 2017	Sep. 30, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill		$ 2,989,270	$ 47,031
Knight-Swift Merger [Member]
Business Acquisition [Line Items]
Fair value of the consideration transferred	$ 3,976,905
Cash and cash equivalents	28,484
Restricted cash and fixed maturity securities	85,615
Trade and other receivables	411,767
Prepaid expenses	44,564
Other current assets	19,736
Property and equipment	1,522,123
Identifiable intangible assets	1,285,900
Other noncurrent assets	18,537
Total assets	3,416,726
Accounts payable	(188,411)
Accrued liabilities	(232,280)
Claims accruals	(306,846)
Long-term debt and capital lease obligations	(894,681)
Deferred tax liabilities	(741,405)
Other long-term liabilities	(18,452)
Total liabilities	(2,382,075)
Goodwill	$ 2,942,254

Purchase Price Allocation - S57

Purchase Price Allocation - Summary of Intangible Assets Acquired (Details) - USD ($) $ in Thousands	Sep. 08, 2017	Sep. 30, 2017
Business Acquisition [Line Items]
Estimated Life		7 years 7 months 6 days
Minimum [Member]
Business Acquisition [Line Items]
Estimated Life		10 years
Maximum [Member]
Business Acquisition [Line Items]
Estimated Life		20 years
Knight-Swift Merger [Member]
Business Acquisition [Line Items]
Customer relationships	$ 817,200
Trade name	468,700
Total identifiable intangible assets	$ 1,285,900

Purchase Price Allocation - S58

Purchase Price Allocation - Summary of Pro Forma Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Business Combinations [Abstract]
Total revenue	$ 3,776,841	$ 3,821,839
Net income	$ 83,727	$ 165,613
Diluted earnings per share (in dollars per share)	$ 0.47	$ 0.92

Purchase Price Allocation - Nar

Purchase Price Allocation - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		Sep. 08, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Business Combinations [Abstract]
Conversion ratio		$ 0.72
Business Acquisition [Line Items]
Merger-related costs			$ 12,338	$ 0	$ 16,516	$ 0
Salaries, wages and benefits			154,390	82,688	316,844	250,732
Miscellaneous operating expenses, net			11,972	4,261	21,873	9,580
Purchased transportation			127,434	57,069	244,358	168,772
Revenues			521,608	280,530	1,066,033	828,936
Net loss	[1]		(3,881)	(23,767)	(36,728)	(71,702)
Amortization of intangibles			2,654	125	2,904	375
Net income (loss)			4,199	$ 24,083	37,564	$ 72,766
Knight Transportation Company [Member]
Business Acquisition [Line Items]
Ownership percentage		46.00%
Swift Transportation Company [Member]
Business Acquisition [Line Items]
Ownership percentage		54.00%
Revenues			242,800		242,800
Net loss			5,500		(8,800)
Knight-Swift Merger [Member]
Business Combinations [Abstract]
Conversion ratio		$ 0.72
Business Acquisition [Line Items]
Fair value of the consideration transferred		$ 3,976,905
Merger-related costs			12,300		16,500
Salaries, wages and benefits		5,600
Miscellaneous operating expenses, net		900
Purchased transportation		$ 100
Amortization of intangibles					$ 2,500
Knight-Swift Merger [Member] | Acquisition-related Costs [Member]
Business Acquisition [Line Items]
Net income (loss)							$ (57,000)
Knight-Swift Merger [Member] | Knight Transportation Company [Member]
Business Acquisition [Line Items]
Share price (in dollars per share)		$ 40.85
Fair Value, Measurements, Nonrecurring [Member]
Business Acquisition [Line Items]
Impairment of intangible assets	[2]		$ 16,746
Equity Awards [Member] | Knight-Swift Merger [Member]
Business Acquisition [Line Items]
Fair value of equity portion awards assumed		$ 13,193
[1]	early adopted ASU 2016-09, Improvements to Employee Share-Based Payment Accounting during the fourth quarter of 2016. The adoption of this standard resulted in the recognition of $1.8 million of excess tax benefits to the income tax provision for the year ended December 31, 2016. Net income and shares outstanding data for the quarter ended and year-to-date September 30, 2016 are presented as if the ASU was adopted at the beginning of 2016.
[2]	During the quarter ended September 30, 2017, we terminated the implementation of the Swift ERP system. This resulted in a pre-tax impairment loss of $16.7 million, which was recorded in "Impairments" within operating income in the condensed consolidated unaudited statements of income.

Purchase Price Allocation - S60

Purchase Price Allocation - Summary of Fair Value of Consideration Transferred (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Sep. 08, 2017	Sep. 09, 2017
Business Acquisition [Line Items]
Conversion ratio	$ 0.72
Knight-Swift Merger [Member]
Business Acquisition [Line Items]
Shares outstanding (in shares)	134,765	97,031
Conversion ratio	$ 0.72
Fair value of the consideration transferred	$ 3,976,905
Knight Transportation Company [Member] | Knight-Swift Merger [Member]
Business Acquisition [Line Items]
Closing price of Knight on September 8, 2017 (in dollars per share)	$ 40.85
Equity Awards [Member] | Knight-Swift Merger [Member]
Business Acquisition [Line Items]
Fair value of equity portion awards assumed	$ 13,193
Common Stock [Member] | Knight-Swift Merger [Member]
Business Acquisition [Line Items]
Fair value of equity portion awards assumed	$ 3,963,712

Goodwill and Other Intangible61

Goodwill and Other Intangible Assets - Summary of Changes in Carrying Amount of Goodwill (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)
Goodwill [Roll Forward]
Goodwill at beginning of period	$ 47,031
Amortization relating to deferred tax assets	(15)
Goodwill related to 2017 Merger	2,942,254
Goodwill at end of period	$ 2,989,270

Goodwill and Other Intangible62

Goodwill and Other Intangible Assets - Narrative (Details) - USD ($)	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill impairment loss	$ 0	$ 0
Finite-Lived Intangible Assets [Line Items]
Estimated Life	7 years 7 months 6 days
Amortization expense, remainder of year	$ 10,500,000
Amortization expense, 2018	41,900,000
Amortization expense, 2019	41,900,000
Amortization expense, 2020	41,800,000
Amortization expense, 2021	41,800,000
Amortization expense, thereafter	$ 41,700,000
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Life	19 years 10 months 24 days

Goodwill and Other Intangible63

Goodwill and Other Intangible Assets - Intangible Asset Balances (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Customer Relationships and Non Compete:
Gross carrying amount	$ 820,900	$ 3,700
Accumulated amortization	(4,029)	(1,125)
Customer relationships and non-compete, net	816,871	2,575
Trade Name:
Gross carrying amount	468,700	0
Intangible assets, net	$ 1,285,571	$ 2,575

Goodwill and Other Intangible64

Goodwill and Other Intangible Assets - Summary of Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Amortization Expense, Year Two	$ 41,900		$ 41,900
Amortization of intangibles	2,654	$ 125	2,904	$ 375
Finite-Lived Intangible Assets, Amortization Expense, Year Four	41,800		41,800
Amortization of intangible assets related to the 2017 Merger [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	2,529	0	2,529	0
Amortization related to intangible assets existing prior to the 2017 Merger [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 125	$ 125	$ 375	$ 375

Investments and Related Commi65

Investments and Related Commitments - Summary of Investment Balances (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Dec. 31, 2003
Schedule of Available-for-sale Securities [Line Items]
Investment, amount	$ 20,707	$ 27,713
Transportation Resource Partners [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment, amount	211	214	$ 5,000
Transportation Resource Partners III [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment, amount	2,146	5,882
Transportation Resource Partners IV [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment, amount	2,580	1,882
Transportation Resource Partners, Colnvest Partners, (NTI) [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment, amount	8,625	10,000
Transportation Resource Partners, CoInvest Partners, (QLS) [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment, amount	$ 7,145	$ 9,735

Investments and Related Commi66

Investments and Related Commitments - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended		33 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2008	Dec. 31, 2006	Dec. 31, 2003
Schedule of Available-for-sale Securities [Line Items]
Investment, amount	$ 20,707,000		$ 20,707,000		$ 20,707,000	$ 27,713,000
Income (Loss) from equity method investments			1,660,000	$ 177,000
Transportation Resource Partners [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment, amount	211,000		211,000		211,000	214,000				$ 5,000,000
Amount committed to invest									$ 5,500,000
Impairment	0	$ 67,000	3,000	67,000
Transportation Resource Partners III [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment, amount	2,146,000		2,146,000		2,146,000	5,882,000
Amount committed to invest								$ 15,000,000
Commitment release							$ 2,100,000
Investments	11,100,000		11,100,000		11,100,000
Remaining investment commitment	1,800,000		1,800,000		1,800,000
Income (Loss) from equity method investments	400,000	32,100	1,500,000	200,000
Distributions from investment	800,000
Proceeds from investment, distributions			5,300,000	400,000
Transportation Resource Partners IV [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment, amount	2,580,000		2,580,000		2,580,000	1,882,000
Amount committed to invest							$ 4,900,000
Impairment			53,000
Remaining investment commitment	2,100,000		2,100,000		2,100,000
Proceeds from investment, distributions			400,000
Payments for investments			1,100,000		2,800,000
Transportation Resource Partners, Colnvest Partners, (NTI) [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment, amount	8,625,000		8,625,000		8,625,000	10,000,000
Remaining investment commitment	0		0		0
Income (Loss) from equity method investments	(300,000)	$ 0	(1,400,000)	$ 0
Payments for investments			10,000,000
Transportation Resource Partners, CoInvest Partners, (QLS) [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment, amount	7,145,000		7,145,000		7,145,000	$ 9,735,000
Remaining investment commitment	0		0		$ 0
Income (Loss) from equity method investments	$ 200,000		1,500,000
Distributions from investment			4,100,000
Payments for investments			$ 9,700,000

Marketable Equity Securities (

Marketable Equity Securities (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Sales proceeds	$ 0	$ 2,220,000	$ 0	$ 7,403,000
Cost of securities sold	0	796,000	0	2,909,000
Realized gain	0	1,424,000	0	4,494,000
Realized gain, net of taxes	0	$ 878,000	0	$ 2,771,000
Available-for-sale securities	$ 0		$ 0		$ 0

Restricted Investments (Details

Restricted Investments (Details) $ in Thousands		9 Months Ended
		Sep. 30, 2017USD ($)Securities	Dec. 31, 2016USD ($)
Schedule of Investments [Line Items]
Cost or Amortized Cost	[1]	$ 22,303	$ 0
Gross Unrealized Gains		1
Gross Unrealized Temporary Losses		(7)
Estimated Fair Value	[1]	$ 22,297	$ 0
Securities with unrealized losses for less than 12 months | Securities		29
United States corporate securities [Member]
Schedule of Investments [Line Items]
Cost or Amortized Cost		$ 16,033
Gross Unrealized Gains		0
Gross Unrealized Temporary Losses		(5)
Estimated Fair Value		16,028
Municipal bonds [Member]
Schedule of Investments [Line Items]
Cost or Amortized Cost		4,990
Gross Unrealized Gains		1
Gross Unrealized Temporary Losses		(2)
Estimated Fair Value		4,989
Negotiable certificate of deposits [Member]
Schedule of Investments [Line Items]
Cost or Amortized Cost		1,280
Gross Unrealized Gains		0
Gross Unrealized Temporary Losses		0
Estimated Fair Value		$ 1,280
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]	Restricted investments are included in "Restricted investments, held to maturity, amortized cost."

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Income Tax Contingency [Line Items]
Effective tax rate	(43.50%)	38.10%	32.10%	39.20%
Decrease in unrecognized tax benefits, reasonably possible	$ 0.7		$ 0.7
Accrued interest and penalties	$ 1.7		$ 1.7		$ 0.4
Minimum [Member]
Income Tax Contingency [Line Items]
Year under income tax examination			2,011
Year subject to examination			2,011
Maximum [Member]
Income Tax Contingency [Line Items]
Year under income tax examination			2,015

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Construction in progress	$ 7	$ 13

Assets Held for Sale (Details)

Assets Held for Sale (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Assets held for sale	$ 24.9	$ 9.6

Notes Receivable - Narrative (D

Notes Receivable - Narrative (Details)	9 Months Ended
	Sep. 30, 2017
Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest on notes receivable	2.00%
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest on notes receivable	20.00%

Notes Receivable - Summary of C

Notes Receivable - Summary of Current and Long-term Balance of Notes Receivables (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Receivables [Abstract]
Notes receivable from independent contractors	$ 10,910	$ 1,039
Notes receivable from third parties	8,292	2,808
Gross notes receivable	19,202	3,847
Allowance for doubtful notes receivable	(559)	(240)
Total notes receivable, net of allowance	18,643	3,607
Current portion, net of allowance	5,984	560
Long-term portion	$ 12,659	$ 3,047

Accounts Receivable Securitiz74

Accounts Receivable Securitization (Details) - 2015 RSA [Member] - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017
Servicing Liabilities at Fair Value [Line Items]
Interest accrual rate		1.80%
program fees	$ 0.4	$ 0.4

Debt and Financing Debt and Fin

Debt and Financing Debt and Financing - Narrative (Details) - USD ($)		9 Months Ended
		Sep. 30, 2017		Sep. 29, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Repayment of Outstanding Debt Balances, Cash on Hand		$ 3,400,000
2017 Agreement, Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 1,200,000,000
2017 Agreement, Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest rate margin		1.125%
2015 Agreement, Credit Facility [Member]
Debt Instrument [Line Items]
Interest rate, percent lower than previous agreement		(0.375%)
2013 Knight Agreement [Member]
Debt Instrument [Line Items]
Interest rate, percent higher than previous agreement		0.50%
Line of Credit [Member] | 2017 Agreement, Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 800,000,000	[1]	800,000,000
Line of credit				85,000,000
Amount of payment	[1]	$ 0
Final maturity date	[1]	Oct. 3, 2022
Line of Credit [Member] | 2015 Agreement, Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 600,000,000
Line of credit		35,000,000
Line of Credit [Member] | 2013 Knight Agreement [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		300,000,000
Line of credit		$ 0			$ 18,000,000
Line of credit, interest rate		1.40%
Line of Credit [Member] | 2013 Knight Agreement [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest rate margin		0.625%
Loans Payable [Member] | 2017 Agreement, Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 400,000,000		$ 400,000,000
Amount of payment		$ 0
Final maturity date		Oct. 2, 2020
Loans Payable [Member] | 2015 Agreement, Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 680,000,000
Line of credit		$ 450,000,000
[1]	The commitment fee for the unused portion of the Revolver is based on our consolidated leverage ratio and ranges from 0.07% to 0.20%. As of September 30, 2017, commitment fees on the unused portion of the Revolver accrued at 0.13% and outstanding letter of credit fees accrued at 1.13%.

Debt and Financing - Debt Terms

Debt and Financing - Debt Terms (Details) - 2017 Agreement, Credit Facility [Member] - USD ($)		9 Months Ended
		Sep. 30, 2017		Sep. 29, 2017
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 1,200,000,000
Line of Credit [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 800,000,000	[1]	800,000,000
Final maturity date	[1]	Oct. 3, 2022
Interest rate base	[1]	LIBOR
Minimum principal payment – amount	[1]	$ 0
Minimum principal payment – frequency	[1]	Once
Minimum principal payment – commencement date	[1]	Oct. 3, 2022
Interest accrual rate		2.36%
Commitment fee percentage, unused portion		0.13%
Outstanding letter of credit fees		1.13%
Line of Credit [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest rate margin	[1],[2]	0.875%
Commitment fee percentage, unused portion		0.07%
Line of Credit [Member] | Maximum [Member]
Debt Instrument [Line Items]
Interest rate margin	[1],[2]	1.50%
Commitment fee percentage, unused portion		0.20%
Loans Payable [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 400,000,000		$ 400,000,000
Final maturity date		Oct. 2, 2020
Interest rate base		LIBOR
Minimum principal payment – amount		$ 0
Minimum principal payment – frequency		Once
Minimum principal payment – commencement date		Oct. 2, 2020
Interest accrual rate		2.36%
Loans Payable [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest rate margin	[2]	0.875%
Loans Payable [Member] | Maximum [Member]
Debt Instrument [Line Items]
Interest rate margin	[2]	1.50%
[1]	The commitment fee for the unused portion of the Revolver is based on our consolidated leverage ratio and ranges from 0.07% to 0.20%. As of September 30, 2017, commitment fees on the unused portion of the Revolver accrued at 0.13% and outstanding letter of credit fees accrued at 1.13%.
[2]	The interest rate margin for the Term Loan and the Revolver is based on our consolidated leverage ratio. As of September 30, 2017, interest accrued at 2.36% on the Term Loan and 2.36% on the Revolver.

Debt and Financing - Debt Balan

Debt and Financing - Debt Balances (Details) - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Long-term debt		$ 399,749	$ 0
Deferred loan costs, term loan A		2,312	0
Less: current portion of long-term debt		(30)	0
Long-term debt – less current portion		399,719	0
Revolving line of credit		85,000	18,000
Long-term debt, including revolving line of credit		484,749	18,000
Other [Member]
Debt Instrument [Line Items]
Long-term debt		453	0
Loans Payable [Member] | 2017 Agreement, Credit Facility [Member]
Debt Instrument [Line Items]
Long-term debt	[1],[2]	399,296	0
Deferred loan costs, term loan A		704	0
Line of Credit [Member] | 2013 Knight Agreement [Member]
Debt Instrument [Line Items]
Revolving line of credit	[2],[3]	0	18,000
Letters of credit outstanding, amount			31,300
Line of Credit [Member] | 2017 Agreement, Credit Facility [Member]
Debt Instrument [Line Items]
Revolving line of credit	[2],[4]	85,000	$ 0
Letters of credit outstanding, amount		$ 124,800
[1]	Carrying value is net of $0.7 million deferred loan costs as of September 30, 2017.
[2]	Refer to Note 21 for information regarding the fair value of long-term debt.
[3]	also had outstanding letters of credit under the Knight Revolver of $31.3 million at December 31, 2016
[4]	The Company also had outstanding letters of credit under the Revolver of $124.8 million at September 30, 2017

Deferred Loan Costs (Details)

Deferred Loan Costs (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Debt Issuance Costs [Line Items]
Deferred loan costs	$ 2,312	$ 0
Other assets
Debt Issuance Costs [Line Items]
Deferred loan costs	1,608	0
Long-term debt, less current portion
Debt Issuance Costs [Line Items]
Deferred loan costs	$ 704	$ 0

Leases - Narrative (Details)

Leases - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Dec. 31, 2016USD ($)lease
Leases [Abstract]
Collateral, revenue equipment, gross cost	$ 178,500,000		$ 178,500,000		$ 0
Collateral, accumulated amortization	1,900,000		1,900,000
Number of capital leases | lease					0
Rental expense	$ 15,400,000	$ 1,300,000	$ 17,900,000	$ 3,700,000

Leases - Summary of Operating L

Leases - Summary of Operating Leases (Details) $ in Thousands	Sep. 30, 2017USD ($)
Leases [Abstract]
2,017	$ 55,912
2,018	177,778
2,019	122,607
2,020	74,832
2,021	39,130
Thereafter	58,984
Future minimum lease payments	$ 529,243

Leases - Summary of Capital Lea

Leases - Summary of Capital Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Leases [Abstract]
2,017	$ 16,198
2,018	51,008
2,019	61,281
2,020	14,984
2,021	30,848
Thereafter	29,463
Future minimum lease payments	203,782
Less: amounts representing interest	(13,681)
Present value of minimum lease payments	190,101
Less: current portion	(54,561)	$ 0
Capital lease obligations, less current portion	$ 135,540	$ 0

Leases - Summary of Operating82

Leases - Summary of Operating Leases as Lessor (Details) $ in Thousands	Sep. 30, 2017USD ($)
Leases [Abstract]
2,017	$ 25,061
2,018	69,208
2,019	35,119
2,020	18,383
2,021	5,196
Thereafter	0
Future minimum lease payments receivable	$ 152,967

Contingencies and Legal Proce83

Contingencies and Legal Proceedings (Details) $ in Millions		1 Months Ended	9 Months Ended
		Oct. 31, 2016driver	Sep. 30, 2017USD ($)	Dec. 31, 2016USD ($)	Mar. 31, 2016USD ($)	Mar. 30, 2016USD ($)
Commitments and Contingencies Disclosure [Abstract]
Loss contingency accrual			$ 126.2
Utah Collective and Individual Arbitration [Member]
Loss Contingencies [Line Items]
Number of drivers | driver		1,300
Employee Compensation and Pay Practices Matters [Member]
Loss Contingencies [Line Items]
Loss contingency, allegations			The plaintiffs allege one or more of the following, pertaining to Washington state-based drivers: that Swift 1) failed to pay minimum wage; 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.
Loss contingency, opinion of counsel			On August 29, 2017, the Parties in the Slack case reached a settlement.  On October 10, 2017, the court granted a motion for preliminary approval of the settlement. The court set a date of January 29, 2018 for the fairness hearing.  The likelihood that a loss has been incurred in the Slack matter is probable.
Employee Compensation and Pay Practices Matters [Member] | Washington Overtime Class Action [Member]
Loss Contingencies [Line Items]
Loss contingency, name of plaintiffs	[1]		Troy Slack (1)
Loss contingency, name of defendant			Swift Transportation Company of Arizona, LLC and Swift Transportation Corporation
Lawsuit filing date			September 9, 2011
Loss contingency, domicile of litigation			United States District Court for the Western District of Washington
Owner-Operator Matters [Member]
Loss Contingencies [Line Items]
Loss contingency, allegations			The putative class alleges that Swift misclassified independent contractors as independent contractors in violation of the FLSA and various state laws, and that such independent contractors should be considered employees. 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.
Loss contingency, opinion of counsel			In January 2017, the district court issued an order finding that the plaintiffs had signed contracts of employment and thus the case could properly proceed in court. Swift has appealed this decision to the Ninth Circuit and the parties have discussed settlement. Based on the above, the likelihood that a loss has been incurred is probable.
Owner-Operator Matters [Member] | Ninth circuit owner operator misclassification class action [Member]
Loss Contingencies [Line Items]
Loss contingency, name of plaintiffs	[1]		Joseph Sheer, Virginia Van Dusen, Jose Motolinia, Vickii Schwalm, Peter Wood (1)
Loss contingency, name of defendant			Swift Transportation Co., Inc., Interstate Equipment Leasing, Inc., Jerry Moyes, and Chad Killebrew
Lawsuit filing date			December 22, 2009
Loss contingency, domicile of litigation			Unites States District Court of Arizona and Ninth Circuit Court of Appeals
Owner-Operator Matters [Member] | Utah Collective and Individual Arbitration [Member]
Loss Contingencies [Line Items]
Loss contingency, allegations			The plaintiffs allege that the Central Parties (defined below) misclassified independent contractor drivers as independent contractors and were therefore liable to these drivers for minimum wages and other employee benefits under the FLSA. The complaint also alleges a federal forced labor claim under U.S.C. §1589 and §1595, as well as fraud and other state-law claims.
Loss contingency, name of plaintiffs	[1]		Gabriel Ciluffo, Kevin Shire, and Bryan Ratterree (1)
Loss contingency, name of defendant			Central Refrigerated Service, Inc., Central Leasing, Inc., Jon Isaacson, and Jerry Moyes (the "Central Parties"), as well as Swift Transportation Company
Lawsuit filing date			June 1, 2012
Loss contingency, domicile of litigation			American Arbitration Association
Loss contingency, opinion of counsel			In October 2016, the arbitrator ruled that approximately 1,300 Central Refrigerated Service, Inc. drivers were improperly classified as independent contractors, when they should have been classified and compensated as employees.  The arbitrator ruled that damages could ultimately be assessed in a collective proceeding and denied Swift’s motion to decertify the collective proceeding.  On April 14, 2017, the parties reached a settlement of the matter.  The parties are currently pursuing court approval of that settlement.  The likelihood that a loss has been incurred is probable.
Knight Transportation Company [Member]
Loss Contingencies [Line Items]
Excess personal injury and property damage liability insurance			$ 130
Insurance aggregate deductible amount			2.5
Self insurance retention workers compensation claims per occurrence					$ 1	$ 0.5
Self retention for employee medical health			0.2	$ 0.2
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
Self insurance aggregate losses			1.5
Knight Transportation Company [Member] | Policy Period, March 1, 2017 to March 1, 2018 [Member]
Loss Contingencies [Line Items]
Self insurance retention			1
Knight Transportation Company [Member] | Policy Period, March 1, 2016 to March 1, 2017 [Member]
Loss Contingencies [Line Items]
Self insurance retention			2.5
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
[1]	Individually and on behalf of all others similarly situated.

Joint Ventures (Details)

Joint Ventures (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2010	Sep. 30, 2017
Schedule of Equity Method Investments [Line Items]
Payments to acquire interest in joint venture	$ 26
Joint venture ownership interest	52.00%
Kold Trans, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of profits		80.00%

Share Repurchase Programs (Deta

Share Repurchase Programs (Details) - USD ($) shares in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Feb. 28, 2016	Dec. 31, 2011
Class of Stock [Line Items]
Amount remaining				$ 4,300,000
Knight Repurchase Plan [Member]
Class of Stock [Line Items]
Share repurchase program, authorized amount		$ 10,000,000				$ 10,000,000
Repurchase and cancellation of Class A Common Stock, shares	100		1,600
Repurchase and cancellation of Class A Common Stock, value	$ 3,300,000	0	$ 39,900,000
Swift Repurchase Plan [Member] | Common Class A [Member]
Class of Stock [Line Items]
Share repurchase program, authorized amount					$ 150,000,000
Repurchase and cancellation of Class A Common Stock, value		0
Amount remaining		$ 62,900,000

Fair Value Measurement - Estima

Fair Value Measurement - Estimated Fair Values (Details) - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
Financial Assets:
Restricted investments, Carrying Value	[1]	$ 22,303	$ 0
Restricted investments, Estimated Fair Value	[1]	22,297	0
Money market funds, carrying value	[2]	1,597	1,385
Money market funds, fair value	[2]	1,597	1,385
Debt securities - municipal securities	[2]	1,728	1,903
Financial Liabilities:
Term loan, due October 2020, Carrying Value		399,749	0
Accounts receivable securitization, due January 2019, Carrying Value		285,000	0
Accounts receivable securitization, due January 2019, Estimated Fair Value		285,000	0
Revolving line of credit, Carrying Value		85,000	18,000
Deferred loan costs		2,312	0
Loans Payable [Member] | 2017 Agreement, Credit Facility [Member]
Financial Liabilities:
Term loan, due October 2020, Carrying Value	[3],[4]	399,296	0
Term loan, due October 2020, Estimated Fair Value	[3]	400,000	0
Deferred loan costs		704	0
Line of Credit [Member] | 2017 Agreement, Credit Facility [Member]
Financial Liabilities:
Revolving line of credit, Carrying Value	[4],[5]	85,000	0
Revolving line of credit, Estimated Fair Value		85,000	0
Line of Credit [Member] | 2013 Knight Agreement [Member]
Financial Liabilities:
Revolving line of credit, Carrying Value	[4],[6]	0	18,000
Revolving line of credit, Estimated Fair Value		$ 0	$ 18,000
[1]	Restricted investments are included in "Restricted investments, held to maturity, amortized cost."
[2]	Items included within "Other long-term assets, restricted cash and investments."
[3]	Carrying value is net of $0.7 million deferred loan costs as of September 30, 2017.
[4]	Refer to Note 21 for information regarding the fair value of long-term debt.
[5]	The Company also had outstanding letters of credit under the Revolver of $124.8 million at September 30, 2017
[6]	also had outstanding letters of credit under the Knight Revolver of $31.3 million at December 31, 2016

Fair Value Measurement - Recurr

Fair Value Measurement - Recurring Basis (Details) - USD ($)		Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, fair value	[1]	$ 1,597,000	$ 1,385,000
Debt securities - municipal securities	[1]	1,728,000	1,903,000
Liabilities, fair value, recurring		0	0
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, fair value		1,597,000	1,385,000
Debt securities - municipal securities		0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, fair value		0	0
Debt securities - municipal securities		1,728,000	1,903,000
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, fair value		0	0
Debt securities - municipal securities		$ 0	$ 0
[1]	Items included within "Other long-term assets, restricted cash and investments."

Fair Value Measurement - Nonrec

Fair Value Measurement - Nonrecurring Measurement (Details) - USD ($)		3 Months Ended
		Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, fair value, nonrecurring		$ 0	$ 0
Assets, fair value, nonrecurring			$ 0
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Finite-lived intangible assets, fair value, nonrecurring	[1]	0
Impairment	[1]	(16,746,000)
Fair Value, Measurements, 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, nonrecurring	[1]	0
Fair Value, Measurements, 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, nonrecurring	[1]	0
Fair Value, Measurements, 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, nonrecurring	[1]	$ 0
[1]	During the quarter ended September 30, 2017, we terminated the implementation of the Swift ERP system. This resulted in a pre-tax impairment loss of $16.7 million, which was recorded in "Impairments" within operating income in the condensed consolidated unaudited statements of income.

Stock Compensation Expense - Al

Stock Compensation Expense - Allocation of Stock Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	$ 1,820	$ 546	$ 3,393	$ 3,126
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	480	434	1,309	1,318
Restricted Stock Units and Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense	$ 1,340	$ 112	$ 2,084	$ 1,808

Stock Compensation Expense - Na

Stock Compensation Expense - Narrative (Details)		Sep. 08, 2017USD ($)$ / shares	Sep. 30, 2017USD ($)shares	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)offering_periodshares	Sep. 30, 2016USD ($)shares	Dec. 31, 2013	Dec. 31, 2012USD ($)shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Conversion ratio | $ / shares		$ 0.72
Share-based compensation expense | $			$ 1,820,000	$ 546,000	$ 3,393,000	$ 3,126,000
Granted (in shares)					497,421
Assumed Swift stock options (in shares)					528,466
Vested (in shares)	[1]				519,483
Dividend yield	[2]				0.72%	0.99%
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Conversion ratio | $ / shares		0.72
Share-based compensation expense | $			480,000	$ 434,000	$ 1,309,000	$ 1,318,000
Unrecognized compensation expense, stock options | $			4,400,000		$ 4,400,000
Unrecognized compensation expense, period for recognition					3 years 8 months 12 days
Granted (in shares)					497,421	569,480
Proceeds from stock options exercised | $					$ 9,700,000	$ 9,300,000
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Conversion ratio | $ / shares		0.72
Unrecognized compensation expense, restricted stock units | $			15,600,000		$ 15,600,000
Unrecognized compensation expense, period for recognition					5 years 3 months 18 days
Granted (in shares)					124,145	10,222
Assumed Swift stock units (in shares)					168,488
Vested (in shares)					126,871
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Conversion ratio | $ / shares		0.72
Unrecognized compensation expense, restricted stock units | $			$ 0		$ 0
Granted (in shares)					0	177,741
Assumed Swift stock units (in shares)					56,817
Recognized expense | $					$ 0
Required service period							3 years
Vested and paid out (in shares)					107,967
Dividend yield	[3]				0.00%	0.99%
Employee Stock [Member] | 2012 ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of authorized shares (in shares)			1,200,000		1,200,000			1,400,000
Required service period								90 days
Maximum percentage of gross income allowed to be elected to purchase common stock								15.00%
Discounted purchase price, percentage of fair value price								95.00%
Number of offering periods | offering_period					4
Duration of offering period					3 months
Maximum value of shares allowed to be purchased per offering period | $								$ 6,250
Maximum value of shares allowed to be purchased per calendar year | $								$ 25,000
Voting interest percentage								5.00%
Weighted Average [Member] | Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, period for recognition					1 year 10 months 24 days
Weighted Average [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, period for recognition					2 years 4 months 24 days
2015 and 2016 Awards [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested (in shares)					329,417
Executive Officer and Director [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested (in shares)					82,099
2014 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of authorized shares (in shares)			3,000,000		3,000,000
Knight-Swift Merger [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Conversion ratio | $ / shares		$ 0.72
Unrecognized compensation expense, restricted stock units | $		$ 6,300,000
Share-based compensation expense | $			$ 100,000		$ 100,000
Knight-Swift Merger [Member] | Equity Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity interests earned | $		$ 13,100,000
[1]	During year-to-date September 30, 2017, 107,967 shares vested and paid out, 329,417 shares vested related to the 2015 and 2016 awards for which the performance measurement period ends December 31, 2017 with no pay out expected, and 82,099 shares vested for certain executive officers for which payout will be at a future date.
[2]	Dividend yield - the dividend yield is based on our historical experience and future expectation of dividend payouts.
[3]	The dividend yield, used to project stock price to the end of the performance period, is based on our historical experience and future expectation of dividend payouts. Total shareholder return is determined assuming that dividends are reinvested in the issuing entity over the performance period, which is mathematically equivalent to utilizing a 0% dividend yield.

Stock Compensation Expense - Op

Stock Compensation Expense - Option Award Activity (Details)	9 Months Ended
	Sep. 30, 2017$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding
Outstanding as of December 31, 2016 (in shares) | shares	1,737,400
Granted (in shares) | shares	497,421
Assumed Swift stock options (in shares) | shares	528,466
Exercised (in shares) | shares	(515,012)
Forfeited (in shares) | shares	(169,616)
Outstanding as of September 30, 2017 (in shares) | shares	2,078,659
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price
Outstanding as of December 31, 2016 (in dollars per share) | $ / shares	$ 23.19
Granted (in dollars per share) | $ / shares	33.35
Assumed Swift stock options (in dollars per share) | $ / shares	21.93
Exercised (in dollars per share) | $ / shares	21.83
Forfeited (in dollars per share) | $ / shares	27.35
Outstanding as of September 30, 2017 (in dollars per share) | $ / shares	$ 25.30

Stock Compensation Expense - St

Stock Compensation Expense - Stock Option Fair Value Assumptions (Details) - $ / shares		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Dividend yield	[1]	0.72%	0.99%
Expected volatility	[2]	27.95%	27.91%
Risk-free interest rate	[3]	1.49%	0.90%
Expected term (in years)	[4]	3 years 2 months 19 days	2 years 8 months 26 days
Weighted-average fair value of options granted (in dollars per share)		$ 6.78	$ 4.28
[1]	Dividend yield - the dividend yield is based on our historical experience and future expectation of dividend payouts.
[2]	Expected volatility - we analyzed the volatility of our stock using historical data.
[3]	Risk-free interest rate - the risk-free interest rate assumption is based on U.S. Treasury securities at a constant maturity with a maturity period that most closely resembles the expected term of the stock option award.
[4]	Expected term - the expected term of employee stock options represents the weighted-average period the stock options are expected to remain outstanding and has been determined based on an analysis of historical exercise behavior.

Stock Compensation Expense - Re

Stock Compensation Expense - Restricted Stock Unit Award Activity (Details) - $ / shares		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares
Vested (in shares)	[1]	(519,483)
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares
Balance as of December 31, 2016 (in shares)		686,786
Granted (in shares)		124,145	10,222
Assumed Swift restricted stock units (in shares)		168,488
Vested (in shares)		(126,871)
Forfeited (in shares)		(35,593)
Balance as of September 30, 2017 (in shares)		816,955
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value
Balance as of December 31, 2016 (in dollars per share)		$ 16.46
Granted (in dollars per share)		33.35
Assumed Swift restricted stock units (in dollars per share)		40.85
Vested (in dollars per share)		16.77
Forfeited (in dollars per share)		21.32
Balance as of September 30, 2017 (in dollars per share)		$ 22.53
[1]	During year-to-date September 30, 2017, 107,967 shares vested and paid out, 329,417 shares vested related to the 2015 and 2016 awards for which the performance measurement period ends December 31, 2017 with no pay out expected, and 82,099 shares vested for certain executive officers for which payout will be at a future date.

Stock Compensation Expense - Pe

Stock Compensation Expense - Performance Restricted Stock Unit Award Activity (Details) - $ / shares		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares
Vested (in shares)	[1]	(519,483)
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares
Balance as of December 31, 2016 (in shares)		508,478
Granted (in shares)		0	177,741
Assumed Swift PRSUs (in shares)		56,817
Shares earned above target (in shares)		21,117
Cancelled (in shares)		(10,112)
Balance as of September 30, 2017 (in shares)		56,817
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price
Balance as of December 31, 2016 (in dollars per share)		$ 25.60
Granted (in dollars per share)		0	$ 23.89
Assumed Swift PRSUs (in dollars per share)		40.85
Shares earned above target (in dollars per share)		23.85
Vested (in dollars per share)	[1]	25.53
Cancelled (in dollars per share)		25.40
Balance as of September 30, 2017 (in dollars per share)		$ 40.85
[1]	During year-to-date September 30, 2017, 107,967 shares vested and paid out, 329,417 shares vested related to the 2015 and 2016 awards for which the performance measurement period ends December 31, 2017 with no pay out expected, and 82,099 shares vested for certain executive officers for which payout will be at a future date.

Stock Compensation Expense - 95

Stock Compensation Expense - Performance Shares Fair Value Assumptions (Details) - $ / shares		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	[1]	0.72%	0.99%
Expected volatility	[2]	27.95%	27.91%
Risk-free interest rate	[3]	1.49%	0.90%
Expected term (in years)	[4]	3 years 2 months 19 days	2 years 8 months 26 days
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	[5]	0.00%	0.99%
Expected volatility	[6]		27.95%
Average peer volatility	[6]		34.37%
Average peer correlation coefficient	[7]		60.00%
Risk-free interest rate	[8]		0.89%
Expected term (in years)	[9]		2 years 10 months 2 days
Weighted-average fair value of PRSUs granted (in dollars per share)		$ 0	$ 23.89
[1]	Dividend yield - the dividend yield is based on our historical experience and future expectation of dividend payouts.
[2]	Expected volatility - we analyzed the volatility of our stock using historical data.
[3]	Risk-free interest rate - the risk-free interest rate assumption is based on U.S. Treasury securities at a constant maturity with a maturity period that most closely resembles the expected term of the stock option award.
[4]	Expected term - the expected term of employee stock options represents the weighted-average period the stock options are expected to remain outstanding and has been determined based on an analysis of historical exercise behavior.
[5]	The dividend yield, used to project stock price to the end of the performance period, is based on our historical experience and future expectation of dividend payouts. Total shareholder return is determined assuming that dividends are reinvested in the issuing entity over the performance period, which is mathematically equivalent to utilizing a 0% dividend yield.
[6]	We (or peer company) estimated volatility using our (or their) historical share price performance over the remaining performance period as of the grant date.
[7]	The correlation coefficients are used to model the way in which each entity tends to move in relation to each other; the correlation assumptions were developed using the same stock price data as the volatility assumptions.
[8]	The risk-free interest rate assumption is based on U.S. Treasury securities at a constant maturity with a maturity period that most closely resembles the expected term of the performance award.
[9]	Since the Monte Carlo simulation valuation is an open form model that uses an expected life commensurate with the performance period, the expected life of the PRSUs was assumed to be the period from the grant date to the end of the performance period.

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017
Related Party Transactions [Abstract]
Monthly consulting fee		$ 200
Restructuring Reserve [Roll Forward]
Accrued consulting fees – Jerry Moyes, September 9, 2017	$ 2,825
Additions to accrual	0
Less: payments	0
Accrued consulting fees – Jerry Moyes, September 30, 2017	$ 2,825	$ 2,825