Schneider National (SNDR) 10-K 26 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2018	Feb. 19, 2019	Jun. 29, 2018
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Trading Symbol	SNDR
Entity Registrant Name	SCHNEIDER NATIONAL, INC.
Entity Central Index Key	1,692,063
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Small Business	false
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity Well-known Seasoned Issuer	Yes
Entity Public Float			$ 1.3
Class A Common Shares
Document Information [Line Items]
Entity Common Stock, Shares Outstanding (shares)		83,029,500
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding (shares)		93,995,072

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Operating revenues	$ 4,977	$ 4,383.6	$ 4,045.7
Operating expenses:
Purchased transportation	1,965.9	1,605.3	1,466
Salaries, wages, and benefits	1,259.4	1,223.5	1,129.3
Fuel and fuel taxes	344.8	305.5	252.9
Depreciation and amortization	291.3	279	266
Operating supplies and expenses	491.3	493.9	449.9
Insurance and related expenses	102.2	90.3	89.1
Other general expenses	144.3	105.8	102.1
Goodwill impairment charge	2	0	0
Total operating expenses	4,601.2	4,103.3	3,755.3
Income from operations	375.8	280.3	290.4
Other expenses (income):
Interest expense—net	12.5	17.4	21.4
Other expense (income)—net	(1.3)	(0.5)	3.4
Total other expenses	11.2	16.9	24.8
Income before income taxes	364.6	263.4	265.6
Provision for (benefit from) income taxes	95.7	(126.5)	108.7
Net income	268.9	389.9	156.9
Other comprehensive income (loss):
Foreign currency translation adjustments	(1)	(0.9)	0.7
Unrealized loss on marketable securities—net of tax	0	0	(0.2)
Total other comprehensive income (loss)	(1)	(0.9)	0.5
Comprehensive income	$ 267.9	$ 389	$ 157.4
Weighted average common shares issued and outstanding	177	171.1	156.6
Basic earnings per common share	$ 1.52	$ 2.28	$ 1
Weighted average diluted shares outstanding (shares)	177.2	171.3	156.8
Diluted earnings per common share	$ 1.52	$ 2.28	$ 1
Dividends per share of common stock (usd per share)	$ 0.24	$ 0.2	$ 0.2

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 378.7	$ 238.5
Marketable securities	51.3	41.6
Trade accounts receivable—net of allowance of $6.8 million and $5.2, million, respectively	593.1	527.9
Other receivables	31.8	22.4
Current portion of lease receivables—net of allowance of $0.5 million and $1.7 million, respectively	129.1	104.9
Inventories	60.8	83.1
Prepaid expenses and other current assets	79.5	75.6
Total current assets	1,324.3	1,094
Property and equipment:
Transportation equipment	2,900.2	2,770.1
Land, buildings, and improvements	177.2	183.8
Other property and equipment	157.6	175.7
Total property and equipment	3,235	3,129.6
Accumulated depreciation	1,312.8	1,271.5
Net property and equipment	1,922.2	1,858.1
Lease receivables	133.2	138.9
Capitalized software and other noncurrent assets	82.6	74.7
Goodwill	162.2	164.8
Total noncurrent assets	2,300.2	2,236.5
Total Assets	3,624.5	3,330.5
Current Liabilities:
Trade accounts payable	226	230.4
Accrued salaries and wages	94.8	85.8
Claims accruals—current	58.3	48.3
Current maturities of debt and capital lease obligations	51.7	19.1
Dividends payable	10.6	8.8
Other current liabilities	81.2	69.6
Total current liabilities	522.6	462
Noncurrent Liabilities:
Long-term debt and capital lease obligations	359.6	420.6
Claims accruals—noncurrent	113.3	102.5
Deferred income taxes	450.6	386.6
Other	46.1	68.6
Total noncurrent liabilities	969.6	978.3
Commitments and Contingencies (Note 16)
Shareholders' Equity:
Additional paid-in capital	1,544	1,534.6
Retained earnings	589.3	355.6
Accumulated other comprehensive income	(1)	0
Total shareholders' equity	2,132.3	1,890.2
Total liabilities and shareholders' equity	3,624.5	3,330.5
Class A Common Shares
Shareholders' Equity:
Common stock	0	0
Class B Common Stock
Shareholders' Equity:
Common stock	$ 0	$ 0

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Trade allowance	$ 6.8	$ 5.2
Allowance for lease receivables	$ 0.5	$ 1.7
Class A Common Shares
Common stock, par value (usd per share)	$ 0	$ 0
Common stock, shares authorized (shares)	250,000,000	250,000,000
Common stock, shares issued (shares)	83,029,500	83,029,500
Common stock, shares outstanding (shares)	83,029,500	83,029,500
Class B Common Stock
Common stock, par value (usd per share)	$ 0	$ 0
Common stock, shares authorized (shares)	750,000,000	750,000,000
Common stock, shares issued (shares)	94,593,588	93,850,011
Common stock, shares outstanding (shares)	93,969,268	93,850,011

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Activities:
Net income	$ 268.9	$ 389.9	$ 156.9
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	291.3	279	266
Gains on sales of property and equipment	(8.1)	(9.4)	(18.3)
Goodwill impairment charge	2	0	0
Deferred income taxes	62.2	(152)	75.6
WSL contingent consideration adjustment	0	(13.5)	0
Long-term incentive compensation expense	22.8	17	18.3
Other noncash items	(3.5)	(0.7)	(1.4)
Changes in operating assets and liabilities:
Receivables	(74.8)	(64.4)	1.1
Other assets	(9)	1.4	(4.9)
Payables	3	16	(0.6)
Other liabilities	11.7	(2)	(37.4)
Net cash provided by operating activities	566.5	461.3	455.3
Investing Activities:
Purchases of transportation equipment	(385.1)	(388.5)	(422.1)
Purchases of other property and equipment	(36.9)	(33.4)	(37)
Proceeds from sale of property and equipment	90.5	70	52
Proceeds from lease receipts and sale of off-lease inventory	94.6	61	63.5
Purchases of lease equipment	(90.5)	(110.1)	(88.4)
Sales of marketable securities	9.9	10.5	11.1
Purchases of marketable securities	(20.1)	0	(14.2)
Acquisition of businesses, net of cash acquired	0	0	(78.2)
Net cash used in investing activities	(337.6)	(390.5)	(513.3)
Financing Activities:
Proceeds under revolving credit agreements	0	0	176
Payments under revolving credit agreements	0	(135)	(89.9)
Proceeds from other debt	0	0	0.5
Payments of debt and capital lease obligations	(28.7)	(123.7)	(28.1)
Payment of deferred consideration related to acquisition	(19.3)	(19.4)	0
Proceeds from IPO, net of issuance costs	0	340.6	0
Dividends paid	(40.7)	(25.5)	(31.3)
Redemptions of redeemable common shares	0	(0.1)	(1.4)
Proceeds from issuances of redeemable common shares	0	0	2.3
Net cash provided by (used in) financing activities	(88.7)	36.9	28.1
Net increase (decrease) in cash and cash equivalents	140.2	107.7	(29.9)
Cash and Cash Equivalents:
Beginning of period	238.5	130.8	160.7
End of period	378.7	238.5	130.8
Noncash investing and financing activity:
Equipment purchases in accounts payable	2.1	9.5	22.4
Dividends declared but not yet paid	10.6	8.8	0
Costs in accounts payable related to our IPO	0	0	2.3
Increase in redemption value of redeemable common shares	0	126.6	110
Ownership interest in Platform Science, Inc.	3.5	0	0
Cash paid (refunded) during the year for:
Interest	15.5	19.2	21.6
Income taxes—net of refunds	$ 39	$ (4.2)	$ 5

Consolidated Statements Shareho

Consolidated Statements Shareholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income
Balance at Dec. 31, 2015	$ 0	$ 0	$ 0	$ 0	$ 0
Increase (Decrease) in Stockholders' Equity
Net income - post-IPO	156.9
Balance at Dec. 31, 2016	0	0	0	0	0
Increase (Decrease) in Stockholders' Equity
Share issuances - IPO	340.6		340.6
Transfer from temporary equity to permanent equity See Note 11, Temporary Equity	1,201.2		1,187	13.3	0.9
Net income - post-IPO	389.9
Other comprehensive loss - post-IPO	(0.9)				(0.9)
Share-based compensation expense	4.8		4.8
Other	0		(1.4)	1.4
Balance at Dec. 31, 2017	1,890.2	0	1,534.6	355.6	0
Increase (Decrease) in Stockholders' Equity
Share issuances - IPO	0.5		0.5
Net income - post-IPO	268.9			268.9
Other comprehensive loss - post-IPO	(1)				(1)
Share-based compensation expense	10.9		10.9
Dividends declared at $0.24 per share	(42.5)			(42.5)
Exercise of employee stock options	0.2		0.2
Shares withheld for employee taxes	(2.3)		(2.3)
Other	0.1		0.1
Balance at Dec. 31, 2018	2,132.3	$ 0	$ 1,544	589.3	$ (1)
Increase (Decrease) in Stockholders' Equity
Cumulative–effect adjustment of ASU 2014-09 adoption See Note 2, Revenue Recognition	$ 7.3			$ 7.3

Consolidated Statements Share_2

Consolidated Statements Shareholders' Equity (Parenthetical) - $ / shares	9 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Stockholders' Equity [Abstract]
Dividends declared per share (usd per share)	$ 0.15	$ 0.24	$ 0.2	$ 0.2

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies (a) Nature of Operations We are a leading transportation and logistics services company providing a broad portfolio of premier truckload, intermodal, and logistics solutions and operating one of the largest for-hire trucking fleets in North America. (b) Basis of Presentation As used in these notes, the term “financial statements” refers to the consolidated financial statements. This includes the consolidated statements of comprehensive income, consolidated balance sheets, consolidated statements of cash flows, and consolidated statements of shareholders' equity unless otherwise noted. Our consolidated financial statements include all of our wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. (c) Use of Estimates The consolidated financial statements contained in this report have been prepared in conformity with GAAP. We make estimates and assumptions that affect assets, liabilities, the disclosure of contingent liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results may differ from these estimates. (d) Cash and Cash Equivalents Cash in excess of current operating requirements is invested in short-term, highly liquid investments. We consider all highly liquid investments purchased with original maturities of three months or less to be cash equivalents. (e) Receivables and Allowance for Doubtful Accounts Our trade accounts receivable and lease receivables are recorded net of an allowance for uncollectible accounts and revenue adjustments. The allowance is based on historical experience and an aging analysis, as well as any known trends or uncertainties related to customer billing and account collectability. The adequacy of our allowance is reviewed at least quarterly. Receivables are reserved when it is probable that amounts related to the receivable will not be collected. In circumstances where we are aware of a specific customer's inability to meet its financial obligations, a specific reserve is recorded against amounts due to reduce the net receivable to the amount reasonably expected to be collected. Bad debt expense is included in other general expenses in the consolidated statements of comprehensive income. (f) Inventory Our inventories consist of tractors and trailing equipment owned by our equipment leasing company to be sold or leased to independent contractors, as well as parts, tires, supplies, and fuel. These inventories are valued at the lower of cost or market using specific identification or average cost. The following table shows the components of our inventory balances as of December 31: (in millions) 2018 2017 Tractors and trailing equipment for sale or lease $ 48.1 $ 69.8 Replacement parts 11.4 11.8 Tires and other 1.3 1.5 Total $ 60.8 $ 83.1 (g) Investments in Marketable Securities Our marketable securities are classified as available for sale and carried at fair value in current assets on the consolidated balance sheets. Our portfolio of securities has maturities ranging from 2 months to 81 months . While our intent is to hold our securities to maturity, sudden changes in the market or to our liquidity needs may cause us to sell certain securities in advance of their maturity date. Any unrealized gains and losses, net of tax, are included as a component of accumulated other comprehensive income on our consolidated balance sheets, unless we determine that an unrealized loss is other-than-temporary. If we determine that an unrealized loss is other-than-temporary, we recognize the loss in earnings. Cost basis is determined using the specific identification method. (h) Fair Value Fair value focuses on the estimated price that would be received to sell an asset or paid to transfer a liability, which is referred to as the exit price. Inputs to valuation techniques used to measure fair value fall into three broad levels (Levels 1, 2, and 3) as follows: Level 1 —Observable inputs that reflect quoted prices for identical assets or liabilities in active markets that we have the ability to access at the measurement date. Level 2 —Observable inputs, other than quoted prices included in Level 1, for the asset or liability or prices for similar assets and liabilities. Level 3 —Unobservable inputs reflecting the reporting entity’s estimates of the assumptions that market participants would use in pricing the asset or liability (including assumptions about risk). Assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. All marketable securities were valued based on quoted prices for similar assets in active markets or quoted prices for identical or similar assets in markets that are not active (Level 2 in the fair value hierarchy). We measure our marketable securities on a recurring, monthly basis. (i) Property and Equipment Property and equipment are recorded at cost. Depreciation is calculated using the straight-line method based on the estimated useful lives and residual values. Generally, the estimated useful lives are as follows: 2018 Tractors 2 - 10 years Trailing equipment 6 - 20 years Other transportation equipment 4 - 5 years Buildings and improvements 5 - 25 years Other property 3 - 10 years Salvage values, when applicable, generally don't exceed 25% of original cost for tractors and trailing equipment and reflect any agreements with tractor suppliers for residual or trade-in values for certain new equipment. Gains and losses on the sale or other disposition of equipment are based on the difference between the proceeds received less costs to sell and the net book value of the assets disposed. Gains and losses are recognized at the time of the sale or disposition and are classified in operating supplies and expenses in the consolidated statements of comprehensive income. (j) Assets Held for Sale Assets held for sale consist of revenue equipment and are included in prepaid expenses and other current assets in the consolidated balance sheets. Reclassification to assets held for sale occurs when the required criteria, as defined by ASC 360, Property, Plant and Equipment , are satisfied. As of December 31, 2018 and 2017 , assets held for sale by segment were as follows: (in millions) 2018 2017 Truckload $ 19.5 $ 35.2 Intermodal 2.4 0.7 Total $ 21.9 $ 35.9 (k) Asset Impairment Goodwill and other intangible assets with indefinite lives are subject to an annual impairment test. Interim impairment tests are performed when impairment indicators are present. Intangible assets with definite lives are reviewed for impairment on an annual basis. Other long-lived assets require an impairment review when events or circumstances indicate that the carrying amount may not be recoverable. We base our evaluation of other long-lived assets on the presence of impairment indicators such as the future economic benefit of the assets, any historical or future profitability measurements, and other external market conditions or factors. We perform annual goodwill impairment tests for each of our reporting units containing goodwill during the fourth quarter of each year. Beginning in 2017, we changed our annual goodwill impairment testing date from December 31 to October 31 to better align the testing date with our financial planning process and alleviate resource constraints. We would not expect a materially different outcome in any given year as a result of testing on October 31 as compared to December 31. The carrying amount of a reporting unit's goodwill is considered not recoverable, and an impairment loss is recorded if the carrying amount of the reporting unit exceeds the reporting unit's fair value, as determined based on a combination of an income approach and a market approach. See Note 7 , Goodwill and Other Intangible Assets , for more information on our goodwill and other intangible assets. The carrying amount of tangible long-lived assets held and used is considered not recoverable if the carrying amount exceeds the undiscounted sum of cash flows expected to result from the use and eventual disposition of the asset. If the carrying amount is not recoverable, the impairment loss is measured as the excess of the asset's carrying amount over its fair value. Assets held for sale are evaluated for impairment at least annually and as impairment indicators are present. The carrying amount of assets held for sale is not recoverable if the carrying amount exceeds the fair value less estimated costs to sell the asset. An impairment loss is recorded for the excess of the asset’s carrying amount over the fair value less estimated costs to sell. Impairment losses are recorded in operating supplies and expenses in the consolidated statements of comprehensive income. Impairment losses were immaterial in 2018 , 2017 and 2016 . (l) Revenue Recognition Through December 31, 2017 , we recorded transportation revenue at the time of delivery. Beginning in 2018, we implemented ASU 2014-09, Revenue from Contracts with Customers, which is codified as ASC 606 and replaces ASC 605, Revenue Recognition . With the adoption of ASC 606, we began recognizing revenue during the delivery period based on relative transit time in each reporting period, with expenses recognized as incurred. Accordingly, a portion of the total revenue that will be billed to the customer once a load is delivered is recognized in each reporting period based on the percentage of the freight pickup and delivery service that has been completed at the end of the reporting period. See Note 2 , Revenue Recognition , for more information on the adoption of ASC 606. When we use third-party carriers, we generally record revenues on the gross basis at amounts charged to our customers because we are the primary obligor, we are a principal in the transaction, we invoice our customers and retain all credit risks, and we maintain discretion over pricing. Additionally, we are responsible for selection of third-party transportation providers to the extent used to satisfy customer freight requirements. We record revenues net of pass-through taxes in our consolidated statements of comprehensive income. For the year ended December 31, 2018 , no customer accounted for more than 10% of our consolidated revenues. We had one customer who accounted for slightly more than 10% of our consolidated revenues in 2017. No customer accounted for more than 10% of our consolidated revenues in 2016. (m) Income Taxes Income taxes are accounted for under the liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized as income or expense in the period that includes the enactment date. We record valuation allowances for deferred tax assets to the extent we believe these assets are not more likely than not to be realized through the reversal of existing taxable temporary differences, projected future taxable income, or tax-planning strategies. We record a liability for unrecognized tax benefits when the benefits of tax positions taken on a tax return are not more likely than not to be sustained upon audit. Interest and penalties related to uncertain tax positions are classified as income tax expense in the consolidated statements of comprehensive income. (n) Earnings Per Share We compute basic earnings per share by dividing net earnings available to common stockholders by the actual weighted average number of common shares outstanding for the reporting period. Diluted earnings per share reflect the potential dilution that could occur if holders of unvested restricted and performance share units or options exercised or converted their holdings into common stock. Awards that would have an antidilutive impact are excluded from the calculation and have been deemed immaterial. As disclosed in Note 3 , IPO , our IPO of shares of Class B Common Stock was effective in April 2017. In connection with the offering, we subsequently sold additional shares of common stock. (o) Share-based Compensation We have share-based compensation plans covering certain employees, including officers and directors. We account for share-based compensation using the fair value recognition provisions of current accounting standards for share-based payments. We grant restricted share units, restricted shares, performance share units, performance shares, and nonqualified stock options. We recognize compensation expense over the requisite service periods within each award. See Note 14 , Share-Based Compensation , for more information about our plans. (p) Claims Accruals We are self-insured for loss of and damage to our owned and leased revenue equipment. We purchase insurance coverage for a portion of expenses related to employee injuries, vehicular collisions, accidents, and cargo damage. Certain insurance arrangements include a level of self-insurance (deductible) coverage applicable to each claim. We have excess policies to limit our exposure to catastrophic claim costs. The amounts of self-insurance change from time to time based on measurement dates, policy expiration dates, and claim type. Our claims accrual policy for all self-insured claims is to recognize a liability at the time of the incident based on our analysis of the nature and severity of the claims and analyses provided by third-party claims administrators, as well as legal, economic, and regulatory factors. The ultimate cost of a claim develops over time as additional information regarding the nature, timing, and extent of damages claimed becomes available. Accordingly, we use an actuarial method to develop current claim information to derive an estimate of our ultimate claim liability. This process involves the use of loss-development factors based on our historical claims experience and includes a contractual premium adjustment factor, if applicable. In doing so, the recorded liability considers future claims growth and provides an allowance for incurred-but-not-reported claims. We do not discount our estimated losses. At December 31, 2018 and 2017 , we had an accrual of approximately $ 156.0 million and $ 147.2 million , respectively, for estimated claims net of reinsurance receivables. In addition, we are required to pay certain advanced deposits and monthly premiums. At December 31, 2018 and 2017 , we had an aggregate prepaid insurance asset of approximately $ 9.2 million and $7.9 million , respectively, which represented prefunded premiums and deposits. (q) Accounting Standards Issued but Not Yet Adopted In August 2018, the FASB issued ASU 2018-15, Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, which aligns the capitalization requirements for implementation costs incurred in a hosting arrangement that is a service contract with the existing capitalization requirements for implementation costs incurred to develop or obtain internal-use software. ASU 2018-15 is effective for us as of January 1, 2020 with early adoption permitted. We currently cannot reasonably estimate the impact the adoption of this ASU will have on our consolidated financial statements. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement - Disclosure Requirements, which removes, modifies, and adds certain disclosure requirements for fair value measurements. ASU 2018-13 is effective for us January 1, 2020 with early adoption permitted. We are currently evaluating the impact the adoption of this ASU will have on our consolidated financial statements and do not believe the impact will be material. In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments , which requires companies to use a forward-looking, expected loss model to estimate credit losses on various types of financial assets and net investments in leases. It also requires additional disclosure related to credit quality of trade and other receivables, including information related to management’s estimate of credit allowances. ASU 2016-13 is effective for us January 1, 2020. We currently cannot reasonably estimate the impact the adoption of this ASU will have on our consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases, which amended authoritative guidance on leases and is codified in ASC 842. The amended guidance requires lessees to recognize most leases on their balance sheets as right-of-use assets along with corresponding lease liabilities. The new standard also requires new disclosures to help financial statement users better understand the amount, timing, and uncertainty of cash flows arising from leases. This guidance was effective for us January 1, 2019. In July 2018, the FASB issued additional authoritative guidance providing companies with the option to apply this ASU to new and existing leases within the scope of the guidance as of the beginning of the period of adoption. We elected this transition method of applying the new lease standard and recognized right-of-use assets, lease liabilities, and any cumulative-effect adjustments to the opening balance of retained earnings as of January 1, 2019. Prior period amounts will not be adjusted and will continue to be reported under the accounting standards in effect for those periods. Upon adoption of the new standard on January 1, 2019, we elected the package of practical expedients provided under the guidance. The practical expedient package applied to leases that commenced prior to adoption of the new standard and permitted companies not to reassess whether existing or expired contracts are or contain a lease, the lease classification, and any initial direct costs for any existing leases. The Company also elected the recognition exemption for equipment leases, which allows the Company to not recognize right-of-use assets and liabilities for leases with an initial term of 12 months or less. Additionally, the Company elected to take the practical expedient to include non-lease components as part of the right-of-use asset and lease liability. A cross-functional implementation team identified the Company's lease population, leveraged and expanded the use of our existing lease software to assist with the reporting and disclosure requirements under the standard, and abstracted and validated our lease information. The adoption of the standard added approximately $80 million in right-of-use assets and related lease obligations to our consolidated balance sheet for operating leases in which we were the lessee as of January 1, 2019. The adoption of this standard did not have a material impact on our consolidated statements of comprehensive income. Leasing activities in which we are the lessor in the transaction are also subject to ASC 842. As a lessor, adopting this standard did not have a material impact on our consolidated balance sheets but will add to both operating revenues and expenses in the consolidated statements of comprehensive income, as certain leases previously treated as direct financing leases will become sales-type leases.

Revenue Recognition

Revenue Recognition	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenue Recognition	REVENUE RECOGNITION We implemented ASU 2014-09, Revenue from Contracts with Customers, which is codified as ASC 606 as of January 1, 2018 and replaces ASC 605, Revenue Recognition. We used the modified retrospective approach for adoption, which required us to record the cumulative effect of the transition through retained earnings as of January 1, 2018. Retained earnings increased by $7.3 million upon adoption. The adjustment related only to contracts that were not completed as of January 1, 2018. The following table shows the amount by which financial statement lines were affected by the adoption of the new standard. The changes relate to the recognition of transportation revenue over time rather than at delivery, as explained below under the Transportation heading. Revenue in transit and the related expenses are recorded within our Other segment, except for FTFM which is recorded within the Truckload segment. Year Ended December 31, 2018 Financial Statement Line Item (in millions) Under ASC 605 Adjustment As Reported Consolidated Statement of Comprehensive Income Operating revenues $ 4,977.6 $ (0.6 ) $ 4,977.0 Purchased transportation 1,965.2 0.7 1,965.9 Salaries, wages, and benefits 1,260.3 (0.9 ) 1,259.4 Total operating expenses 4,601.4 (0.2 ) 4,601.2 Income from operations 376.2 (0.4 ) 375.8 Provision for income taxes 364.6 — 364.6 Net income 269.3 (0.4 ) 268.9 Comprehensive income 268.3 (0.4 ) 267.9 December 31, 2018 Financial Statement Line Item (in millions) Under ASC 605 Adjustment As Reported Consolidated Balance Sheet Prepaid expenses and other current assets $ 59.8 $ 19.7 $ 79.5 Total current assets 1,304.6 19.7 1,324.3 Total assets 3,604.8 19.7 3,624.5 Other current liabilities 70.8 10.4 81.2 Total current liabilities 512.2 10.4 522.6 Deferred income taxes 448.2 2.4 450.6 Total noncurrent liabilities 967.2 2.4 969.6 Retained earnings 582.4 6.9 589.3 Total shareholders' equity 2,125.4 6.9 2,132.3 Total liabilities and shareholders' equity 3,604.8 19.7 3,624.5 Year Ended December 31, 2018 Financial Statement Line Item (in millions) Under ASC 605 Adjustment As Reported Consolidated Statement of Cash Flows Operating Cash Flows Net income $ 269.3 $ (0.4 ) $ 268.9 Change in: Other assets (8.7 ) (0.3 ) (9.0 ) Change in: Payables 3.0 — 3.0 Change in: Other liabilities 11.0 0.7 11.7 ASC 606 requires us to look at revenue from customers at a contract level to determine the appropriate accounting. As defined by the new standard, a “contract” can range from an individual order to a multi-year agreement with a customer, depending on the specific arrangement. The majority of our revenues are related to transportation and have similar characteristics. The following table breaks down our revenues by type of service, and each type of service is further described below. Year Ended December 31, Disaggregated Revenues ( in millions ) 2018 2017 Transportation $ 4,589.7 $ 4,012.4 Logistics management 228.3 220.2 Other 159.0 151.0 Total operating revenues $ 4,977.0 $ 4,383.6 Transportation Transportation revenues relate to the Truckload and Intermodal reportable segments, as well as to our Brokerage business, which is included in the Logistics reportable segment. In the Transportation portfolio, our service obligation to customers is satisfied over time. We do not believe there is a significant impact on the nature, amount, timing, and uncertainty of revenue or cash flows based on the mode of transportation. The economic factors that impact our transportation revenue are generally consistent across these modes given the relatively short term nature of each contract. For the majority of our transportation business, the “contract with a customer” is identified as an individual order under a negotiated agreement. Some consideration is variable in that a final transaction price is uncertain and is susceptible to factors outside of the Company's influence, such as the weather or the accumulation of accessorial charges. Pricing information is supplied by the rate schedules that accompany negotiated contracts. Transportation orders are short-term in nature and generally have terms of significantly less than one year. They do not include significant financing components. A small portion of revenues in our transportation business relate to fixed payments in our Truckload segment. These payments are due regardless of volumes, and in these arrangements, the master agreement rather than the individual order may be considered the “contract.” See the Remaining Performance Obligations table below for more information on fixed payments. Prior to the adoption of ASC 606, we recognized revenue from transportation services when we completed our obligation to the customer, upon delivery. In accordance with the new standard, we now recognize revenue over the period transportation services are provided to the customer, including service performed as of the end of the reporting period for loads currently in transit, in order to recognize the value that is transferred to a customer over the course of the transportation service. We determine revenue in transit using the input method, under which revenue is recognized based on time lapsed from the departure date (start of transportation services) to the arrival date (completion of transportation services). Measurement of revenue in transit requires the application of significant judgment. We calculate the estimated percentage of an order's transit time that is complete at period end, and we apply that percentage of completion to the order's estimated revenue. Revenue recognized in the period ended December 31, 2018 includes amounts related to orders that were partially completed (in transit) in prior periods. In certain transportation arrangements, an unrelated party contributes a specified service to our customer. For example, we contract with third-party carriers to perform transportation services on behalf of our customers in our Brokerage business, and we use third-party rail carriers in our Intermodal segment. In situations that include the contributions of third parties, we act as principal in the arrangement, and, accordingly, we recognize gross revenues from these transactions. Logistics Management Logistics Management revenues relate to our Supply Chain Management and Import/Export Services operating segments, both of which are included in our Logistics reportable segment. Within this portfolio, the key service we provide to the customer is management of freight shipping and/or storage. The “contracts” in our Logistics Management portfolio are the negotiated agreements, which contain both fixed and variable components. The variability of revenues is driven by volumes and transactions, which are known as of an invoice date. See the Remaining Performance Obligations table below for additional information. Supply Chain Management and Import/Export Services contracts typically have terms that extend beyond one year, and they do not include financing components. Prior to the adoption of ASC 606, we recognized revenue under these contracts over time, based on pricing terms within the arrangements. Our recognition model will remain the same under the new standard, as we have elected to use the right to invoice practical expedient, which reflects the fact that a customer obtains the benefit associated with logistics services as they are provided (output method). In our Supply Chain Management business, we subcontract third parties to perform a portion of the services. We are responsible for ensuring the services are performed and that they are acceptable to the customer, and we are, therefore, considered to be the principal in these arrangements. Other Other revenues relate to activities that are out of scope for purposes of ASC 606, including our leasing and captive insurance businesses. Quantitative Disclosure The following table provides information related to transactions and expected timing of revenue recognition related to performance obligations that are fixed in nature and relate to contracts with terms greater than one year. Remaining Performance Obligations (in millions) December 31, 2018 Expected to be recognized within one year Transportation $ 5.6 Logistics Management 17.4 Expected to be recognized after one year Transportation 2.2 Logistics Management 4.0 Total $ 29.2 This disclosure does not include revenue related to performance obligations that are part of a contract whose original expected duration is one year or less. In addition, this disclosure does not include expected consideration related to performance obligations for which the Company elects to recognize revenue in the amount it has a right to invoice (e.g., usage-based pricing terms). The following table provides information related to contract balances associated with our contracts with customers as of the dates shown. Contract Balances ( in millions ) December 31, 2018 January 1, 2018 Other current assets - Contract assets $ 21.7 $ 22.2 Other current liabilities - Contract liabilities — — We generally receive payment within 40 days of completion of performance obligations. Contract assets in the table above relate to revenue in transit at the end of the reporting period. Contract liabilities relate to amounts that customers paid in advance of the associated service. For certain of our contracts, we incur upfront costs to fulfill the master agreement, including driver recruiting and equipment relocation, that are capitalized and amortized over the master contract term, which has been deemed to be the period of benefit. These costs usually relate to dedicated transportation arrangements. The following table presents the amounts capitalized for contract fulfillment costs as of the dates shown. (in millions) December 31, 2018 January 1, 2018 Capitalized contract fulfillment costs $ 5.0 $ 3.7 Amortization of capitalized contract fulfillment costs was as shown: Year Ended December 31, (in millions) 2018 2017 Amortization of contract fulfillment costs $ 2.5 $ 2.0 Impairment losses for the periods ended December 31, 2018 and December 31, 2017 were immaterial. Practical Expedients We elected to use the following practical expedients that are available under ASC 606: (i) not to adjust the promised amount of consideration for the effects of a significant financing component when we expect, at contract inception, that the period between our transfer of a promised service to a customer and when the customer pays for that service will be one year or less; (ii) to apply the new revenue standard to a portfolio of contracts (or performance obligations) with similar characteristics, as we reasonably expect that the effects on the consolidated financial statements of applying this guidance to the portfolio would not differ materially from applying this guidance to the individual contracts (or performance obligations) within that portfolio; and (iii) to recognize revenue in the Logistics Management portfolio in the amount of consideration to which we have a right to invoice, that corresponds directly with the value to the customer of the service completed to date.

IPO

IPO	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
IPO	IPO Our IPO of shares of Class B Common Stock was completed in early April 2017, and additional shares were sold in May 2017 under an option granted to the underwriters. In connection with the offering, we sold a total of 20,145,000 shares of Class B common stock at $19 per share and received proceeds of $382.7 million. Expenses related to the offering totaled approximately $42.1 million, resulting in net proceeds of $340.6 million.

Acquisition

Acquisition	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Acquisition	ACQUISITION On June 1, 2016, we acquired 100% of the shares of WSL for $150.4 million in cash and future payments. WSL combines final-mile delivery with an innovative technology platform to provide LTL, truckload, and logistics services for large parcel goods, such as furniture and floor coverings, across North America. It uses proprietary technology to handle supply chain complexities within the national home delivery industry. We acquired WSL because it creates integrated first to final mile delivery capabilities, which reduce supply chain complexities for omnichannel retailers and manufacturers. The acquisition was accounted for as a purchase in accordance with ASC Topic 805, Business Combinations . Assets acquired and liabilities assumed were recorded in the Truckload segment at their fair values as of the acquisition date, as shown in the table below. The fair values of identifiable intangible assets, which were primarily customer relationships and trade names, were based on valuations using the income approach. The excess of the purchase price over the estimated fair values of tangible assets, identifiable intangible assets, and assumed liabilities was recorded as goodwill. The goodwill is attributable to expected synergies and expected growth opportunities. We believe that 100% of the goodwill will be deductible for United States income tax purposes. (in millions) Recognized amounts of identifiable assets acquired and liabilities assumed As of June 1, 2016 Cash $ 1.3 Receivables 16.2 Inventories 0.5 Prepaid expenses and other current assets 4.4 Property and equipment 81.8 Capitalized software and other noncurrent assets 5.8 Intangible assets 10.9 Goodwill 138.2 Total assets acquired 259.1 Payables assumed 7.8 Accrued liabilities assumed 5.3 Current maturities of debt and capital lease obligations assumed 47.7 Debt and capital lease obligations assumed 46.2 Other noncurrent liabilities assumed 1.7 Fair value of total consideration transferred $ 150.4 In addition to cash of $79.5 million paid at closing, the purchase and sale agreement included guaranteed payments of $20.0 million to the former owners of WSL on each of the first three anniversary dates of the closing. The liability recorded was discounted between one percent and three percent , based on credit-adjusted discount rates. The initial payment in the amount of $19.7 million, including calculated interest based on the discounted amount recorded, was made in June 2017 and reflected an adjustment for a working capital true-up. The second payment in the amount of $20.0 million was made in June 2018. The present value of the remaining payment was $18.7 million at December 31, 2018 , which is recorded in other current liabilities on the consolidated balance sheet. A contingent payment arrangement based on the achievement of specified earnings targets is also in place for three consecutive 12-month periods after the closing, with the aggregate payment total not to exceed $40.0 million. No payments have been made through December 31, 2018 . See Note 5 , Fair Value , for information regarding the fair value of this contingent arrangement. Acquisition-related costs included in other general expenses in our consolidated statements of comprehensive income for the year ended December 31, 2016, were $1.4 million . The representative of the former owners of WSL has claimed that we have not fulfilled certain obligations under the purchase and sale agreement relating to the post-closing operation of the business and that, as a result, the former owners are entitled to an accelerated payment of the contingent amount described above without regard to whether the specified earnings targets are met. We believe this claim is meritless and have filed an action in the Delaware Court of Chancery seeking a declaratory judgment that we have complied with our obligations under the agreement and that no accelerated payment is owed. The representative of the former owners has filed a counterclaim seeking the full amount of the accelerated payment. The following unaudited pro forma condensed combined financial information presents our results as if we had acquired WSL on January 1, 2016. (in millions, except per share data) Year Ended December 31, 2016 Pro forma net sales $ 4,119.3 Pro forma net income 155.0 Basic earnings per share as reported 1.00 Pro forma basic earnings per share 0.99 Diluted earnings per share as reported 1.00 Pro forma diluted earnings per share 0.99

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value	FAIR VALUE Fair Value of WSL Contingent Consideration The fair value of the contingent consideration related to the 2016 acquisition of WSL was zero at December 31, 2018 . This valuation was based on significant inputs that are not observable in the market, which are referred to as Level 3 inputs. One of the key assumptions was a probability-adjusted level of earnings before interest, taxes, depreciation, and amortization. The following table sets forth a reconciliation of changes in the fair value of the contingent consideration: (in millions) 2018 2017 Beginning balance $ — $ 13.5 Change in fair value — (13.5 ) Ending balance $ — $ — We recorded adjustments to the contingent consideration liability in the second, third, and fourth quarters of 2017, resulting in an increase in income from operations. The adjustments were caused by a change in the fair value of the contingent liability, which reflected three -year growth targets established by the seller prior to the close of the acquisition. No payments have been made through December 31, 2018 . See Note 6 , Investments , for information on the fair value of our marketable securities. Our ownership interest in Platform Science, Inc. discussed in Note 6 , Investments , was valued based on Level 3 inputs. There were no transfers between levels for the periods shown. Fair Value of Other Financial Instruments The recorded value of cash, trade accounts receivable, and trade accounts payable approximates fair value. The table below presents the carrying value of our debt portfolio along with the fair value of a fixed-rate debt portfolio with similar terms and maturities, which is based on borrowing rates available to us in the applicable year. This valuation used Level 2 inputs. December 31, 2018 December 31, 2017 (in millions) Carrying Amount Fair Value Carrying Amount Fair Value Fixed-rate debt portfolio $ 405.0 $ 398.4 $ 429.8 $ 432.4

Investments

Investments	12 Months Ended
	Dec. 31, 2018
Investments Schedule [Abstract]
Investments	INVESTMENTS Marketable Securities The following table presents the values of our marketable securities as of the dates shown. December 31, 2018 December 31, 2017 (in millions) Amortized Cost Fair Value Amortized Cost Fair Value Zero coupon bonds $ 3.9 $ 3.9 $ 3.8 $ 3.9 U.S. treasury and government agencies 20.0 19.8 6.0 6.0 Asset-backed securities 0.1 0.1 0.3 0.3 Corporate debt securities 15.1 15.0 9.1 9.2 State and municipal bonds 12.5 12.5 22.7 22.2 Total marketable securities $ 51.6 $ 51.3 $ 41.9 $ 41.6 Gross realized gains and losses on marketable securities were not material for the years ended December 31, 2018 , 2017 , and 2016 , respectively. Unrealized gains and losses on marketable securities were not material for the years ended December 31, 2018 , and 2017 , respectively. Ownership Interest in Platform Science, Inc. In 2018, we received a 30% ownership interest in Platform Science, Inc. in exchange for our contribution of a non-exclusive license for telematics mobile software that was developed to enable driver productivity and ensure regulatory compliance. Our ownership interest in Platform Science, Inc. is being accounted for under ASC 321, Investments - Equity Securities and is recorded at fair value in other noncurrent assets on the consolidated balance sheets. The fair value of our ownership interest at December 31, 2018 was determined to be $3.5 million through an independent valuation and is recorded in other income in the consolidated statements of comprehensive income.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2018
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 identifiable net assets acquired. The following table shows changes to our goodwill balances by segment during the years ended December 31, 2018 and December 31, 2017 . (in millions) Truckload Logistics Other Total Balance at December 31, 2016 $ 138.2 $ 14.2 $ 11.6 $ 164.0 Foreign currency translation — — 0.8 0.8 Balance at December 31, 2017 138.2 14.2 12.4 164.8 Goodwill impairment charge — — (2.0 ) (2.0 ) Foreign currency translation — — (0.6 ) (0.6 ) Balance at December 31, 2018 $ 138.2 $ 14.2 $ 9.8 $ 162.2 At December 31, 2018 and 2017 , we had accumulated goodwill impairment charges of $ 8.0 million and $ 6.0 million, respectively. During the second quarter of 2018, we reorganized the structure of the operating segments within the Truckload reportable segment to include FTFM as a separate operating segment and integrated the remaining Dedicated activities into the VTL operating segment. Each Truckload operating segment was determined to be its own reporting unit due to the level at which financial information is available and management reviews that information. As a result of the reorganization, goodwill within the Truckload reportable segment, which was previously attributable to the Dedicated reporting unit, was reallocated to the VTL-Dedicated Services and FTFM reporting units on a relative fair value basis. After the reallocation of goodwill, an impairment test was performed for these reporting units, and it was determined that goodwill was not impaired as each reporting unit had an estimated fair value in excess of its respective carrying amount. In the fourth quarter of 2018 , annual impairment tests were performed on all four of our reporting units with goodwill. As a result of the testing performed, an impairment loss of $2.0 million was recorded for our Asia reporting unit as the discounted cash flows expected to be generated by this reporting unit were not sufficient to recover its carrying value. The identifiable intangible assets other than goodwill listed below are included in capitalized software and other noncurrent assets on the consolidated balance sheets. Our customer lists and trade names are amortized over weighted-average amortization periods of ten and three years, respectively. December 31, 2018 December 31, 2017 (in millions) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Customer lists $ 10.5 $ 3.5 $ 7.0 $ 10.5 $ 2.5 $ 8.0 Trade names 1.4 1.2 0.2 1.4 0.7 0.7 Total intangible assets $ 11.9 $ 4.7 $ 7.2 $ 11.9 $ 3.2 $ 8.7 Amortization expense for intangible assets was $1.4 million, $1.5 million and $0.9 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively. Accumulated amortization in the table above includes foreign currency translation related to a customer list. Estimated future amortization expense related to intangible assets is as follows (in millions): 2019 $ 1.1 2020 1.0 2021 1.0 2022 1.0 2023 1.0 2024 and thereafter 2.1 Total $ 7.2

Debt and Credit Facilities

Debt and Credit Facilities	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Debt and Credit Facilities	DEBT AND CREDIT FACILITIES As of December 31, 2018 and 2017 , debt included the following: (in millions) December 31, 2018 December 31, 2017 Unsecured senior notes: principal payable at maturities ranging from 2019 through 2025; interest payable in semiannual installments through the same time frame; weighted-average interest rate of 3.36% for both 2018 and 2017 $ 400.0 $ 400.0 Equipment financing notes: principal and interest payable in monthly installments through 2019; weighted average interest rate of 3.72% and 3.76% for 2018 and 2017, respectively 5.0 29.8 Total principal outstanding 405.0 429.8 Current maturities of debt (45.0 ) (15.2 ) Debt issuance costs (0.6 ) (0.9 ) Long-term debt $ 359.4 $ 413.7 Scheduled principal payments of debt subsequent to December 31, 2018 are as follows: Years ending December 31, (in millions) 2019 $ 45.0 2020 55.0 2021 40.0 2022 60.0 2023 70.0 2024 and thereafter 135.0 Total $ 405.0 On August 6, 2018, we entered into a $ 250.0 million Credit Agreement (the “2018 Credit Facility”) among us, the lenders party thereto (the “Lenders”) and JPMorgan Chase Bank, N.A., as administrative agent, and terminated our prior $250.0 million Credit Agreement dated February 18, 2011 (as amended). The 2018 Credit Facility is a revolving credit facility that matures on August 6, 2023 and allows us to request an increase in total commitment by up to $150.0 million for a total potential commitment of $400.0 million . The 2018 Credit Facility also provides a sublimit of $100.0 million to be used for the issuance of letters of credit. The applicable interest rate under the 2018 Credit Facility is based on the Prime Rate, the Federal Funds Rate, or the LIBOR, depending upon the type of borrowing, plus an applicable margin based on our consolidated net debt coverage ratio as of the end of each fiscal quarter. We had no outstanding borrowings under this agreement as of December 31, 2018 or 2017 . Standby letters of credit under this agreement amounted to $3.9 million at both December 31, 2018 and 2017 , respectively, and were primarily related to the requirements of certain of our real estate leases. On September 5, 2018, we entered into a Joinder and Amendment No. 2 to our Amended and Restated Receivables Purchase Agreement (the “2018 Receivables Purchase Agreement”) relating to our $200.0 million secured accounts receivable facility. The 2018 Receivables Purchase Agreement has a scheduled maturity date of September 3, 2021, allows us to borrow funds against qualifying trade receivables at rates based on one-month LIBOR, and provides for the issuance of standby letters of credit. We had no outstanding borrowings under this facility at December 31, 2018 or 2017 . At December 31, 2018 and 2017 , standby letters of credit under this agreement amounted to $65.3 million and $63.8 million , respectively, and were primarily related to the requirements of certain of our insurance obligations. Financing arrangements require us to maintain certain covenants and financial ratios. The credit agreements contain various financial and other covenants, including required minimum consolidated net worth, consolidated net debt, limitations on indebtedness, transactions with affiliates, shareholder debt, and restricted payments. The credit agreements and senior notes contain change of control provisions pursuant to which a change of control is defined to mean the Schneider family no longer owns more than 50% of the combined voting power of our capital shares. A change of control event causes an immediate termination of unused commitments under the credit agreements as well as requires repayment of all outstanding borrowings plus accrued interest and fees. The senior notes require us to provide notice to the note holders offering prepayment of the outstanding principal along with interest accrued to the date of prepayment. The prepayment date is required to be within 20 to 60 days from the date of notice. At December 31, 2018 , the Company was in compliance with all financial covenants.

Leases

Leases	12 Months Ended
	Dec. 31, 2018
Leases [Abstract]
Leases	LEASES As lessee — We have various real estate and equipment lease agreements. At December 31, 2018 , scheduled future minimum lease payments under operating leases having initial or remaining noncancelable lease terms of more than one year and capital leases were as follows: (in millions) Operating Leases Capital Leases 2019 $ 35.8 $ 6.9 2020 25.7 0.2 2021 14.9 — 2022 8.4 — 2023 6.8 — 2024 and thereafter 12.7 — Total $ 104.3 7.1 Amount representing interest (0.2 ) Present value of minimum lease payments 6.9 Current maturities (6.7 ) Long-term capital lease obligations $ 0.2 Lease expense for all operating leases was $ 37.0 million , $ 38.0 million, and $ 45.6 million in 2018 , 2017 , and 2016 , respectively, and is classified in operating supplies and expenses in the consolidated statements of comprehensive income. The consolidated balance sheets include assets acquired under capital leases as components of property and equipment as of December 31, 2018 and 2017 , as follows: (in millions) 2018 2017 Transportation equipment $ 19.9 $ 25.0 Real property 0.8 0.8 Other property 0.6 0.6 Accumulated amortization (11.2 ) (12.6 ) Total $ 10.1 $ 13.8 As lessor — We finance various types of transportation-related equipment for independent third parties. The transactions are generally for one year to five years and are accounted for as sales-type leases with fully guaranteed residual values or direct financing leases. As of December 31, 2018 and 2017 , the investment in lease receivables was as follows: (in millions) 2018 2017 Future minimum payments to be received on leases $ 140.0 $ 141.2 Guaranteed residual lease values 151.0 130.7 Total minimum lease payments to be received 291.0 271.9 Unearned income (28.7 ) (28.1 ) Net investment in leases 262.3 243.8 Current maturities of lease receivables 129.6 106.6 Less—allowance for doubtful accounts (0.5 ) (1.7 ) Current portion of lease receivables—net of allowance 129.1 104.9 Lease receivables—noncurrent $ 133.2 $ 138.9 The principal amounts to be received on lease receivables as of December 31, 2018 , were as follows: Years ending December 31 (in millions) 2019 $ 149.0 2020 112.7 2021 29.0 2022 0.3 2023 — 2024 and thereafter — Total $ 291.0 Leases are generally placed on nonaccrual status (nonaccrual of interest and other fees) when a payment becomes 90 days past due or upon receipt of notification of bankruptcy, upon the death of a customer, or in other instances in which management concludes collectability is not reasonably assured. The accrual of interest and other fees is resumed when all payments are less than 60 days past due. At December 31, 2018 , there were $ 0.3 million of lease payments greater than 90 days past due. The terms of the lease agreements generally give us the ability to take possession of the underlying asset in the event of default. We may incur credit losses in excess of recorded allowances if the full amount of any anticipated proceeds from the sale or re-lease of the asset supporting the third party’s financial obligation is not realized. Costs to repossess and estimated reconditioning costs are recorded in the consolidated statements of comprehensive income in the period incurred.
Leases	LEASES As lessee — We have various real estate and equipment lease agreements. At December 31, 2018 , scheduled future minimum lease payments under operating leases having initial or remaining noncancelable lease terms of more than one year and capital leases were as follows: (in millions) Operating Leases Capital Leases 2019 $ 35.8 $ 6.9 2020 25.7 0.2 2021 14.9 — 2022 8.4 — 2023 6.8 — 2024 and thereafter 12.7 — Total $ 104.3 7.1 Amount representing interest (0.2 ) Present value of minimum lease payments 6.9 Current maturities (6.7 ) Long-term capital lease obligations $ 0.2 Lease expense for all operating leases was $ 37.0 million , $ 38.0 million, and $ 45.6 million in 2018 , 2017 , and 2016 , respectively, and is classified in operating supplies and expenses in the consolidated statements of comprehensive income. The consolidated balance sheets include assets acquired under capital leases as components of property and equipment as of December 31, 2018 and 2017 , as follows: (in millions) 2018 2017 Transportation equipment $ 19.9 $ 25.0 Real property 0.8 0.8 Other property 0.6 0.6 Accumulated amortization (11.2 ) (12.6 ) Total $ 10.1 $ 13.8 As lessor — We finance various types of transportation-related equipment for independent third parties. The transactions are generally for one year to five years and are accounted for as sales-type leases with fully guaranteed residual values or direct financing leases. As of December 31, 2018 and 2017 , the investment in lease receivables was as follows: (in millions) 2018 2017 Future minimum payments to be received on leases $ 140.0 $ 141.2 Guaranteed residual lease values 151.0 130.7 Total minimum lease payments to be received 291.0 271.9 Unearned income (28.7 ) (28.1 ) Net investment in leases 262.3 243.8 Current maturities of lease receivables 129.6 106.6 Less—allowance for doubtful accounts (0.5 ) (1.7 ) Current portion of lease receivables—net of allowance 129.1 104.9 Lease receivables—noncurrent $ 133.2 $ 138.9 The principal amounts to be received on lease receivables as of December 31, 2018 , were as follows: Years ending December 31 (in millions) 2019 $ 149.0 2020 112.7 2021 29.0 2022 0.3 2023 — 2024 and thereafter — Total $ 291.0 Leases are generally placed on nonaccrual status (nonaccrual of interest and other fees) when a payment becomes 90 days past due or upon receipt of notification of bankruptcy, upon the death of a customer, or in other instances in which management concludes collectability is not reasonably assured. The accrual of interest and other fees is resumed when all payments are less than 60 days past due. At December 31, 2018 , there were $ 0.3 million of lease payments greater than 90 days past due. The terms of the lease agreements generally give us the ability to take possession of the underlying asset in the event of default. We may incur credit losses in excess of recorded allowances if the full amount of any anticipated proceeds from the sale or re-lease of the asset supporting the third party’s financial obligation is not realized. Costs to repossess and estimated reconditioning costs are recorded in the consolidated statements of comprehensive income in the period incurred.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES On December 22, 2017, the Tax Cuts and Jobs Act (the “Act”) was signed into law. In accordance with GAAP, the effects of this legislation were recognized in 2017 upon enactment. The primary impact of the Act for us related to the reduction of the Federal corporate income tax rate from 35% to 21% beginning in 2018. At December 31, 2017 , our previously recorded deferred tax assets and liabilities were remeasured to reflect the 21% rate at which these assets and liabilities would be realized in future periods. The net change in deferred taxes was recorded through our provision for income taxes. The provisional amounts recorded at December 31, 2017, in accordance with SEC Staff Accounting Bulletin No. 118, were finalized during the fourth quarter of 2018 and had an immaterial impact on the consolidated financial statements. In February 2018, the FASB issued ASU 2018-02, Income Statement - Reporting Comprehensive Income, which allowed for a reclassification from accumulated other comprehensive income to retained earnings of stranded tax effects resulting from the Act. We early adopted this ASU during the fourth quarter of 2018, and the reclassification of stranded income tax effects had an immaterial impact on our consolidated financial statements. The components of the provision for income taxes as of December 31, 2018 , 2017 and 2016 , were as follows: (in millions) 2018 2017 2016 Current: Federal $ 21.7 $ 19.3 $ 24.4 State and other 11.8 5.6 7.5 33.5 24.9 31.9 Deferred: Federal 54.2 71.4 71.2 State and other 6.7 6.7 5.6 Impact of the Tax Cuts and Jobs Act 1.3 (229.5 ) — 62.2 (151.4 ) 76.8 Total provision for (benefit from) income taxes $ 95.7 $ (126.5 ) $ 108.7 Foreign operations of the Company are insignificant in relation to our overall operating results. The provision for income taxes as of December 31, 2018 , 2017 , and 2016 differed from the amounts computed using the federal statutory rates in effect of 21% for December 31, 2018 and 35% for December 31, 2017 and 2016 , as follows: 2018 2017 2016 (in millions, except percentages) Dollar Impact Rate Dollar Impact Rate Dollar Impact Rate Income tax at federal statutory rate $ 76.6 21.0 % $ 92.2 35.0 % $ 93.0 35.0 % State tax, net of federal effect 15.4 4.2 % 8.6 3.3 % 10.5 3.9 % Nondeductible meals and entertainment 2.1 0.6 % 3.4 1.3 % 3.4 1.3 % Impact of the Tax Cuts and Jobs Act 1.3 0.3 % (229.5 ) (87.1 )% — — Other, net 0.3 0.1 % (1.2 ) (0.5 )% 1.8 0.7 % Total provision for (benefit from) income taxes $ 95.7 26.2 % $ (126.5 ) (48.0 )% $ 108.7 40.9 % The components of the net deferred tax liability included in deferred income taxes in the consolidated balance sheets as of December 31, 2018 and 2017 , were as follows: (in millions) 2018 2017 Deferred tax assets: Allowances for doubtful accounts $ 1.1 $ 1.1 Compensation and employee benefits 14.7 15.6 Insurance and claims accruals 2.6 2.8 State net operating losses and credit carryforwards 18.2 17.7 Other 5.0 4.0 Total gross deferred tax assets 41.6 41.2 Valuation allowance (5.8 ) (4.4 ) Total deferred tax assets, net of valuation allowance 35.8 36.8 Deferred tax liabilities: Property and equipment 466.5 410.8 Prepaid expenses 4.3 3.6 Intangibles 11.1 8.7 Other 4.5 0.3 Total gross deferred tax liabilities 486.4 423.4 Net deferred tax liability $ 450.6 $ 386.6 Unrecognized Tax Benefits Our unrecognized tax benefits as of December 31, 2018 would reduce the provision for income taxes if subsequently recognized. Potential interest and penalties related to unrecognized tax benefits are recorded in income tax expense. Interest and penalties recorded in income tax expense for the years ended December 31, 2018 , 2017 , and 2016 were immaterial. Accrued interest and penalties for such unrecognized tax benefits as of December 31, 2018 and 2017 were $1.4 million and $1.2 million , respectively. We expect no significant increases or decreases for unrecognized tax benefits during the twelve months immediately following the December 31, 2018 reporting date. As of December 31, 2018 , 2017 , and 2016 , a reconciliation of the beginning and ending amount of unrecognized tax benefits, which is recorded as other noncurrent liabilities in the consolidated balance sheets, is as follows: (in millions) 2018 2017 2016 Gross unrecognized tax benefits - beginning of year $ 2.8 $ 2.4 $ 2.0 Gross increases - tax positions related to current year 0.8 0.4 0.5 Gross decreases - tax positions taken in prior years — — (0.1 ) Lapse of statutes (0.3 ) — — Gross unrecognized tax benefits - end of year $ 3.3 $ 2.8 $ 2.4 Tax Examinations We file a U.S. federal income tax return, as well as income tax returns in a majority of state tax jurisdictions. We also file returns in foreign jurisdictions. The years 2015, 2016 and 2017 are open for examination by the Internal Revenue Service (“IRS”), and various years are open for examination by state and foreign tax authorities. In September 2018, the statute for 2014 expired. State and foreign jurisdictional statutes of limitations generally range from three to four years. Carryforwards As of December 31, 2018 , we had $224.7 million of state net operating loss carryforwards which are subject to expiration from 2019 to 2039. We also had state credit carryforwards of $0.4 million , which are subject to expiration from 2019 to 2027, and no capital loss carryforwards. The deferred tax assets related to carryforwards at December 31, 2018 were $17.9 million for state net operating loss carryforwards and $0.3 million for state credit carryforwards. Carryforwards are reviewed for recoverability based on historical taxable income, the expected reversals of existing temporary differences, tax-planning strategies, and projections of future taxable income. At December 31, 2018 , we carried a total valuation allowance of $5.8 million , which represents $5.5 million against state deferred tax assets and $0.3 million against state credit carryforwards.

Temporary Equity

Temporary Equity	12 Months Ended
	Dec. 31, 2018
Temporary Equity Disclosure [Abstract]
Temporary Equity	TEMPORARY EQUITY Prior to our IPO in April 2017, our Class A and Class B Common Stock was considered redeemable under GAAP because of certain repurchase rights granted to our shareholders pursuant to the Schneider National, Inc. Employee Stock Purchase Plan and certain agreements governing ownership of our common stock held by existing shareholders, including members of the Schneider family and their family trusts. As a result, all vested Class A and Class B common shares were recorded as temporary equity (redeemable common shares) on the consolidated balance sheets at their redemption value as of the respective balance sheet dates. Accumulated earnings on the consolidated balance sheets were adjusted for the changes during the period in the current redemption value of vested Class A and Class B redeemable common shares. All contractual redemption features were removed at the time of the IPO. As a consequence, all outstanding shares of Class A and Class B Common Stock ceased to be considered temporary equity and were reclassified to Shareholders’ Equity, including the associated balances of accumulated earnings and accumulated other comprehensive income. As the common shares have no par value, the amounts recorded in temporary equity for the share redemption value were recorded to additional paid-in capital within Shareholders’ Equity upon the transfer. The following table shows changes to temporary equity during the year ended December 31, 2017 . Class A Redeemable Common Shares Class B Redeemable Common Shares Accumulated Earnings Accumulated Other Comprehensive Income (in millions) Shares Amount Shares Amount Total Balance—December 31, 2016 83.0 $ 563.2 73.3 $ 497.2 $ 125.1 $ 0.9 $ 1,186.4 Net income — — — — 22.6 — 22.6 Other comprehensive income — — — — — — — Dividends declared at $0.05 per share — — — — (7.8 ) — (7.8 ) Change in redemption value of redeemable common shares — 67.3 — 59.3 (126.6 ) — — Transfer from temporary equity to common equity (83.0 ) (630.5 ) (73.3 ) (556.5 ) (13.3 ) (0.9 ) (1,201.2 ) Balance—December 31, 2017 — $ — — $ — $ — $ — $ —

Common Equity

Common Equity	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Common Equity	COMMON EQUITY On March 21, 2017, the Board declared pro rata share dividends entitling each holder of our Class A and Class B common stock outstanding as of March 21, 2017 to receive 29 shares of Class A or Class B common stock for each share of Class A or Class B common stock held by the shareholder. The share dividend was accounted for as a 30 -for-1 stock split and is retroactively reflected in these consolidated financial statements. All share redemption provisions mentioned in Note 11 , Temporary Equity , were removed effective with the IPO of Class B common shares in April 2017. Therefore, all Class A and Class B common shares were reclassified from temporary equity to permanent equity as of April 2017. Prior to the IPO, restricted share awards that were not yet vested and held for more than 180 days were classified as liabilities at their redemption values, taking into consideration the portion of the requisite service that had been provided as of the reporting date. At the IPO date, these unvested shares were reclassified to equity. Earnings Per Share As disclosed in Note 3 , IPO , our IPO of shares of Class B Common Stock was effective in April 2017. In connection with the offering, we sold additional shares of common stock. Year Ended December 31, (in millions, except per share data) 2018 2017 2016 Numerator: Net income available to common shareholders $ 268.9 $ 389.9 $ 156.9 Denominator: Weighted average common shares issued and outstanding 177.0 171.1 156.6 Effect of dilutive restricted share units 0.2 0.2 0.2 Weighted average diluted common shares issued and outstanding 177.2 171.3 156.8 Basic earnings per common share $ 1.52 $ 2.28 $ 1.00 Diluted earnings per common share $ 1.52 $ 2.28 $ 1.00 The calculation of diluted earnings per share for the twelve months ended December 31, 2018 excluded an immaterial amount of share-based compensation awards that had an anti-dilutive effect. Subsequent Event - Dividends Declared In January 2019, our Board of Directors declared a quarterly cash dividend for the first fiscal quarter of 2019 in the amount of $0.06 per share to holders of our Class A and Class B common stock. The dividend is payable to shareholders of record at the close of business on March 15, 2019, and is expected to be paid on April 8, 2019.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2018
Retirement Benefits [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS We sponsor defined contribution plans for certain eligible employees. Under these plans, annual contribution levels, as defined in the plan agreements, are based upon years of service. Expense under these plans totaled $12.0 million , $11.2 million , and $10.7 million in 2018 , 2017 , and 2016 , respectively, and is classified in salaries, wages, and benefits in the consolidated statements of comprehensive income. We also have a savings plan, organized pursuant to Section 401(k) of the Internal Revenue Code, to provide employees with additional income upon retirement. Under the terms of the plan, substantially all employees may contribute a percentage of their annual compensation, as defined, to the plan. We make contributions to the plan, up to a maximum amount per employee, based upon a percentage of employee contributions. Our net expense under this plan was $12.1 million , $10.7 million , and $10.0 million in 2018 , 2017 , and 2016 , respectively.

Share-based Compensation

Share-based Compensation	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based Compensation	SHARE-BASED COMPENSATION We grant various equity-based awards relating to Class B Common Stock under our 2017 Omnibus Incentive Plan (“the Plan”). These awards consist of the following: restricted shares, restricted stock units (“RSUs”), performance-based restricted shares (“Performance Shares”), performance-based restricted stock units (“PSUs”), and non-qualified stock options. Prior to our IPO, we granted restricted shares of Class B Common Stock. The pre-IPO restricted shares must be paid out in shares and are accounted for as equity awards. We account for our restricted shares, RSUs, performance shares, PSUs, and non-qualified stock options granted as equity awards in accordance with the applicable accounting standards for these types of share-based payments. These standards require that the cost of the awards be recognized in our consolidated financial statements based on the grant date fair value of those awards. This cost is recognized over the period for which an employee is required to provide service in exchange for the award, subject to the attainment of performance metrics established for performance-based restricted shares and PSUs. Share-based compensation expense is recorded in salaries, wages, and benefits in our consolidated statements of comprehensive income, along with other compensation expenses to employees. The following table summarizes the components of our share-based compensation program expense: (in millions) Year Ended December 31, 2018 2017 2016 Restricted Shares and RSUs $ 3.1 $ 1.5 $ — Pre-IPO Restricted Shares 0.9 1.9 2.2 Performance Shares and PSUs 5.5 1.2 — Nonqualified Stock Options 1.4 0.6 — Share-based compensation expense $ 10.9 $ 5.2 $ 2.2 Related tax benefit $ 2.8 $ 2.0 $ 0.9 As of December 31, 2018 , we had $11.6 million of pre-tax unrecognized compensation cost related to outstanding share-based compensation awards that is expected to be recognized over a weighted-average period of 2.5 years . Restricted Shares and RSUs Under the Plan, the majority of the restricted shares and RSUs granted in 2017 and 2018 vest ratably over a four -year period, with the first 25% of the grant vesting approximately one year after the date of grant, subject to continued employment through the vesting date or retirement eligibility. Dividend equivalents equal to dividends paid on our common shares during the vesting period are tracked and accumulated for each restricted share and RSU. The dividend equivalents are forfeitable and are distributed to participants in cash consistent with the date the awards vest. A portion of the restricted shares relate to a one-time 2018 grant, which vests 50% after a five -year period, with the remaining 50% vesting after a six -year period after the grant date, subject to continued employment through the vesting date. Dividend equivalents equal to dividends paid on our common shares during the vesting period are tracked and accumulated for each restricted share. The dividend equivalents are distributed to participants in cash consistent with the date the awards vest. Restricted Shares and RSUs Number of Awards Weighted Average Grant Date Fair Value Unvested at December 31, 2016 — $ — Granted 246,516 19.00 Vested — — Forfeited (6,500 ) 19.00 Unvested at December 31, 2017 240,016 19.00 Granted 229,272 26.82 Vested (74,828 ) 19.00 Forfeited (24,983 ) 21.26 Unvested at December 31, 2018 369,477 $ 23.70 Prior to our IPO, we granted restricted shares of Class B Common Stock. Shares included in the pre-IPO restricted share grants vest ratably over a three -year period. Cash dividends are not paid on the unvested pre-IPO restricted shares, nor do they accumulate during the vesting period. Pre-IPO Restricted Shares Number of Awards Weighted Average Grant Date Fair Value Unvested at January 1, 2016 798,960 $ 5.63 Granted 386,370 6.78 Vested (398,220 ) 5.42 Forfeited (9,900 ) 6.17 Unvested at December 31, 2016 777,210 6.31 Granted — — Vested (621,722 ) 7.59 Forfeited (a) (3,289 ) 19.00 Unvested at December 31, 2017 152,199 19.00 Granted — — Vested (101,643 ) 19.00 Forfeited (6,225 ) 19.00 Unvested at December 31, 2018 44,331 $ 19.00 (a) In April 2017, unvested restricted shares were adjusted to the IPO share price of $19.00 . Performance Shares and PSUs Performance shares and PSUs include a three -year performance period with vesting based on attainment of threshold performance of earnings and return on capital targets. These awards cliff-vest at the end of the three -year performance period, subject to continued employment through the vesting date or retirement eligibility, and payout ranges from 0% - 200% for PSUs and from 0% - 100% for performance shares. Dividend equivalents equal to dividends paid on our common shares during the vesting period are tracked and accumulated for each award. The dividend equivalents are forfeitable and are distributed to participants in cash consistent with the date the awards vest. Performance Shares and PSUs Number of Awards Weighted Average Grant Date Fair Value Unvested at December 31, 2016 — $ — Granted 396,201 19.00 Vested — — Forfeited (4,660 ) 19.00 Unvested at December 31, 2017 391,541 19.00 Granted 303,228 26.78 Vested — — Forfeited (56,390 ) 19.65 Unvested at December 31, 2018 638,379 $ 22.64 Nonqualified Stock Options The options granted under the Plan have an exercise price equal to the fair market value of the underlying stock at the date of grant and vest ratably over a four -year period, with the first 25% of the grant becoming exercisable approximately one year after the date of grant. The options expire ten years from the date of grant. Nonqualified Stock Options Outstanding Number of Awards Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (1) (In years) (In thousands) Outstanding at December 31, 2016 — $ — — $ — Granted 229,620 19.00 — — Exercised (2) — — — — Forfeited — — — — Outstanding at December 31, 2017 229,620 $ 19.00 9.3 $ 2,195 Granted 173,024 26.74 — — Exercised (2) (8,410 ) 19.00 — 67 Forfeited (25,230 ) 19.00 — — Outstanding at December 31, 2018 369,004 $ 22.63 8.7 $ — Exercisable as of: December 31, 2017 — — — — December 31, 2018 48,995 $ 19.00 8.3 $ — (1) The aggregate intrinsic value was computed using the closing share price on December 31, 2018 of $ 18.67 and on December 29, 2017 of $ 28.56 , as applicable. (2) Cash received upon exercise of stock options was $0.2 million in 2018 and $0 in 2017. Unvested Nonqualified Stock Options Number of Awards Weighted Average Grant Date Fair Value Unvested at December 31, 2016 — $ — Granted 229,620 6.37 Vested — — Forfeited — — Unvested at December 31, 2017 229,620 6.37 Granted 173,024 8.96 Vested (57,405 ) 6.37 Forfeited (25,230 ) 6.37 Unvested at December 31, 2018 320,009 $ 7.77 We estimated the grant date fair value of option awards using the Black-Scholes option pricing model. The Black-Scholes option valuation model uses assumptions over the expected term of the options. We used volatility analysis of comparable companies to determine the expected volatility of the stock. We used market data to estimate option exercise and employee termination within the valuation model. The expected term of options granted was based on the average of the contractual term and the weighted average of the vesting term, and it represents the average period of time that options granted are expected to be outstanding. The risk-free rate for periods within the contractual life of the option is based on the U.S. Treasury yield curve in effect at the time of grant. Assumptions used in calculating the Black-Scholes value of options granted during 2018 and 2017 were as follows: Year Ended December 31, 2018 Year Ended December 31, 2017 Weighted-average Black-Scholes value $ 8.96 $ 6.37 Black-Scholes Assumptions: Expected term 6.25 years 6.25 years Expected volatility 32.2 % 35.0 % Expected dividend yield 0.9 % 1.1 % Risk-free interest rate 2.8 % 2.2 % Director Share Awards and Deferred Stock Units Equity awards are granted to each director annually on the date of our annual shareholder meeting, prospectively for the year of service following the annual shareholder meeting, and will vest on the earlier of (1) the one-year anniversary of the grant date and (2) the following year's shareholder meeting, subject to continued service. Any director who joins our Board mid-year will receive a pro-rata portion of equity-based compensation for service during the balance of the director's service year, which will vest on the date of the next annual meeting. We also grant equity retainer awards, or shares in lieu of cash retainer awards, on a quarterly basis to our non-employee directors. These awards consist of fully vested shares of our Class B Common Stock or deferred stock units (“DSUs”) that are granted in arrears on the first business day following a quarter close. The number of shares or DSUs granted each quarter is determined by dividing the quarterly retainer amount by the fair market value of the shares of common stock as of the grant date. We account for both the annual and quarterly director share awards and DSUs as liability awards in accordance with the applicable accounting standards for these types of share-based payments. Expense associated with director equity awards was $1.4 million in both 2018 and 2017 .

Other Long-Term Incentive Compe

Other Long-Term Incentive Compensation	12 Months Ended
	Dec. 31, 2018
Compensation Related Costs [Abstract]
Other Long-Term Incentive Compensation	OTHER LONG-TERM INCENTIVE COMPENSATION We maintain legacy long-term cash incentive compensation plans. The total expense recognized for the plans that include executives was $11.2 million in 2018 , $10.8 million in 2017 , and $13.7 million in 2016 . Under the 2011 Omnibus Long-term Incentive Plan (the “LTIP”), performance-based Long-Term Cash Awards (“Cash Plan Awards”) and service-based Stock Appreciation Rights (“SARs”) were granted to eligible employees, including our executive officers. Our Board of Directors originally adopted and approved the LTIP on February 7, 2011 and approved an amended and restated LTIP on November 8, 2011 and December 31, 2012. Payout on our Cash Plan Awards, which were granted annually from 2013-2016, is contingent on attainment of two pre-established performance metrics, measured over a five -year period: compounded net income growth (determined on the basis of GAAP with adjustments for significant, nonrecurring items approved by the Compensation Committee of the Board of Directors) and return on capital (“ROC”). While each grant is expressed as a fixed dollar amount, the actual amount earned may range from 0% to 250% of target for superior performance. The awards cliff-vest after three years, with payout occurring after completion of the five -year performance period, subject to compliance with certain restrictive covenants. Vested awards are paid out 90 days following completion of the five -year performance period, or on a subsequent deferral date elected by the executive pursuant to our 2005 Supplemental Savings Plan. The liability for the Cash Plan Awards was $22.7 million and $25.6 million at December 31, 2018 and 2017 , respectively. SARs awards, which were granted in 2011 and 2012, became 100% vested on the date provided in the applicable award agreement (a three -year vesting period). Vested SARs were to be paid out on March 1 of the fifth year following the year of such grant (or as soon as practicable thereafter, but in no event later than June 1), or will be paid out on a subsequent deferral date elected by the participant (or within 90 days following a termination of employment or change in control, if earlier, subject to Internal Revenue Code Section 409A). Until payment, SARs will continue to appreciate (or depreciate) with changes in book value of outstanding common shares of company stock. The value of the SARs upon payment will equal the excess, if any, of the book value of a common share on the date of payment over the grant price set forth in the applicable award agreement, multiplied by the number of vested SARs, and subject to the discretion of the Compensation Committee. As of December 31, 2018 , 2.5 million SARs units were outstanding. The liability for the SARs awards was $9.0 million and $8.4 million at December 31, 2018 and 2017 , respectively. Under the 2005 Schneider National, Inc. Long-Term Incentive Plan (the “2005 LTIP”), awards of cash-settled retention credits were granted, including to certain of our named executive officers. Our Board of Directors adopted and approved the 2005 LTIP effective January 1, 2005. The retention credits are mandatorily deferred time-based cash credits which typically vest in 20% increments over a five -year period based on continued employment. Vested retention credits are paid out in March following the second anniversary of the date of the employee’s termination of employment, provided the employee has not violated the terms of their restrictive covenant agreements. The liability for the retention credits was $8.6 million and $8.8 million at December 31, 2018 and 2017 , respectively.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES In the ordinary course of conducting our business we become involved in certain legal matters and investigations on a number of matters, including liability claims, taxes other than income taxes, contract disputes, employment, and other litigation matters. We accrue for anticipated costs to defend and resolve matters that are probable and estimable. We believe the outcomes of these matters will not have a material impact on our business or our financial statements. At December 31, 2018 , our firm commitments to purchase transportation equipment totaled approximately $265.5 million.

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Segment Reporting	SEGMENT REPORTING We have three reportable segments – Truckload, Intermodal, and Logistics – which are based primarily on the services each segment provides. As of December 31, 2017 , our operating segments within the Truckload reportable segment were VTL, Dedicated, and Bulk. During the second quarter of 2018, we reorganized the structure of the Truckload reportable segment, separating FTFM into its own operating segment and moving the remaining business that was previously under the Dedicated operating segment into the VTL operating segment. The Truckload reportable segment now consists of three operating segments (VTL, FTFM, and Bulk) that are aggregated because they have similar economic characteristics and meet the other aggregation criteria described in the accounting guidance for segment reporting. Van Truckload delivers truckload quantities over irregular routes using dry van trailers. First to Final Mile is similar except that it delivers large parcel consumer items, such as furniture, mattresses, and other household goods. Bulk transports key inputs to manufacturing processes, such as specialty chemicals using specialty trailers. The Intermodal reportable segment provides rail intermodal and drayage services to our customers. Company-owned containers, chassis, and dray tractors are used to provide these transportation services. The Logistics reportable segment consists of three operating segments (Brokerage, Supply Chain Management, and Import/Export Services) that are aggregated because they have similar economic characteristics and meet the other aggregation criteria described in the accounting guidance for segment reporting. In the Logistics segment, we provide additional sources of truck capacity, manage transportation-systems analysis requirements for individual customers, and provide trans-loading and warehousing services. We generate other revenues from a captive insurance business and from a leasing business which are operated by wholly owned subsidiaries. We also have operations in Asia that meet the definition of an operating segment. None of these operations meets the quantitative reporting thresholds. As a result, these operations are grouped in “Other” in the tables below. We have also included in “Other” revenues and expenses that are incidental to our activities and are not attributable to any of the reportable segments. The chief operating decision maker (CODM) reviews revenue for each segment without the inclusion of fuel surcharge revenue. For segment purposes, any fuel surcharge revenues earned are recorded as a reduction of the segment’s fuel expenses. For all operating segments except FTFM, revenue is recognized upon delivery, and in-transit revenue is not reflected in segment results. Income from operations at a segment level reflects the measures presented to the CODM for each segment. Separate balance sheets are not prepared by segment and, as a result, assets are not separately identifiable by segment. All transactions between reporting segments are eliminated in consolidation. The following tables summarize our segment information. Intersegment revenues were immaterial for all segments, with the exception of Other, which included revenues from insurance premiums charged to other segments for workers’ compensation, auto, and other types of insurance. Intersegment revenues included in Other revenues below were $82.7 million, $78.4 million and $54.4 million for the years ended December 31, 2018 , 2017 , and 2016 respectively. Revenues by Segment (in millions) Year Ended December 31, 2018 2017 2016 Truckload $ 2,268.0 $ 2,187.4 $ 2,091.0 Intermodal 953.5 779.9 757.5 Logistics 1,024.6 834.3 737.7 Other 322.0 293.6 240.5 Fuel surcharge 522.8 386.3 294.0 Inter-segment eliminations (113.9 ) (97.9 ) (75.0 ) Operating revenues $ 4,977.0 $ 4,383.6 $ 4,045.7 Income (Loss) from Operations by Segment (in millions) Year Ended December 31, 2018 2017 2016 Truckload $ 240.5 $ 196.2 $ 221.1 Intermodal 130.2 52.3 46.1 Logistics 47.4 34.2 30.7 Other (42.3 ) (2.4 ) (7.5 ) Income from operations $ 375.8 $ 280.3 $ 290.4 Depreciation and Amortization Expense by Segment (in millions) Year Ended December 31, 2018 2017 2015 Truckload $ 211.0 $ 205.9 $ 192.6 Intermodal 39.8 34.5 30.9 Logistics 0.4 0.4 0.4 Other 40.1 38.2 42.1 Depreciation and amortization expense $ 291.3 $ 279.0 $ 266.0 Substantially all of our revenues and assets were generated or located within the United States.

Quarterly Results of Operations

Quarterly Results of Operations (Unaudited)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results of Operations (Unaudited)	QUARTERLY RESULTS OF OPERATIONS (Unaudited) (in millions, except per share amounts)* First Quarter Second Quarter Third Quarter Fourth Quarter Full Year 2018 Operating revenues $ 1,139.0 $ 1,236.3 $ 1,280.1 $ 1,321.6 $ 4,977.0 Income from operations 67.6 91.7 97.9 118.6 375.8 Net income 47.6 65.8 70.7 84.8 268.9 Basic earnings per share 0.27 0.37 0.40 0.48 1.52 Diluted earnings per share 0.27 0.37 0.40 0.48 1.52 2017 Operating revenues $ 1,006.4 $ 1,075.2 $ 1,110.8 $ 1,191.2 $ 4,383.6 Income from operations 43.5 79.0 64.1 93.7 280.3 Net income** 22.6 46.5 36.9 283.9 389.9 Basic earnings per share** 0.14 0.27 0.21 1.60 2.28 Diluted earnings per share** 0.14 0.27 0.21 1.60 2.28 * Table may not sum due to rounding ** Fourth quarter 2017 results include the impact of the Tax Cuts and Jobs Act, see Note 10 , Income Taxes , for more information .

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts	Schedule II - Valuation and Qualifying Accounts (in Million Allowance for Doubtful Accounts and Revenue Adjustments for the Year Ended Balance at Beginning of Year Charged to Expense / Against Revenue Write-offs, Net of Recoveries Balance at End of Year December 31, 2016 $ 3.6 $ (0.3 ) $ 0.2 $ 3.5 December 31, 2017 3.5 3.7 (2.0 ) 5.2 December 31, 2018 5.2 3.7 (2.1 ) 6.8

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation As used in these notes, the term “financial statements” refers to the consolidated financial statements. This includes the consolidated statements of comprehensive income, consolidated balance sheets, consolidated statements of cash flows, and consolidated statements of shareholders' equity unless otherwise noted. Our consolidated financial statements include all of our wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates, Policy	Use of Estimates The consolidated financial statements contained in this report have been prepared in conformity with GAAP. We make estimates and assumptions that affect assets, liabilities, the disclosure of contingent liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results may differ from these estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash in excess of current operating requirements is invested in short-term, highly liquid investments. We consider all highly liquid investments purchased with original maturities of three months or less to be cash equivalents.
Accounts Receivable and Allowance	Receivables and Allowance for Doubtful Accounts Our trade accounts receivable and lease receivables are recorded net of an allowance for uncollectible accounts and revenue adjustments. The allowance is based on historical experience and an aging analysis, as well as any known trends or uncertainties related to customer billing and account collectability. The adequacy of our allowance is reviewed at least quarterly. Receivables are reserved when it is probable that amounts related to the receivable will not be collected. In circumstances where we are aware of a specific customer's inability to meet its financial obligations, a specific reserve is recorded against amounts due to reduce the net receivable to the amount reasonably expected to be collected. Bad debt expense is included in other general expenses in the consolidated statements of comprehensive income.
Inventory	Inventory Our inventories consist of tractors and trailing equipment owned by our equipment leasing company to be sold or leased to independent contractors, as well as parts, tires, supplies, and fuel. These inventories are valued at the lower of cost or market using specific identification or average cost
Investments in Marketable Equity Securities	Investments in Marketable Securities Our marketable securities are classified as available for sale and carried at fair value in current assets on the consolidated balance sheets. Our portfolio of securities has maturities ranging from 2 months to 81 months . While our intent is to hold our securities to maturity, sudden changes in the market or to our liquidity needs may cause us to sell certain securities in advance of their maturity date. Any unrealized gains and losses, net of tax, are included as a component of accumulated other comprehensive income on our consolidated balance sheets, unless we determine that an unrealized loss is other-than-temporary. If we determine that an unrealized loss is other-than-temporary, we recognize the loss in earnings. Cost basis is determined using the specific identification method.
Fair Value	Fair Value Fair value focuses on the estimated price that would be received to sell an asset or paid to transfer a liability, which is referred to as the exit price. Inputs to valuation techniques used to measure fair value fall into three broad levels (Levels 1, 2, and 3) as follows: Level 1 —Observable inputs that reflect quoted prices for identical assets or liabilities in active markets that we have the ability to access at the measurement date. Level 2 —Observable inputs, other than quoted prices included in Level 1, for the asset or liability or prices for similar assets and liabilities. Level 3 —Unobservable inputs reflecting the reporting entity’s estimates of the assumptions that market participants would use in pricing the asset or liability (including assumptions about risk). Assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. All marketable securities were valued based on quoted prices for similar assets in active markets or quoted prices for identical or similar assets in markets that are not active (Level 2 in the fair value hierarchy). We measure our marketable securities on a recurring, monthly basis.
Property and Equipment	Property and Equipment Property and equipment are recorded at cost. Depreciation is calculated using the straight-line method based on the estimated useful lives and residual values.
Assets Held for Sale	Assets Held for Sale Assets held for sale consist of revenue equipment and are included in prepaid expenses and other current assets in the consolidated balance sheets. Reclassification to assets held for sale occurs when the required criteria, as defined by ASC 360, Property, Plant and Equipment , are satisfied.
Asset Impairment	Asset Impairment Goodwill and other intangible assets with indefinite lives are subject to an annual impairment test. Interim impairment tests are performed when impairment indicators are present. Intangible assets with definite lives are reviewed for impairment on an annual basis. Other long-lived assets require an impairment review when events or circumstances indicate that the carrying amount may not be recoverable. We base our evaluation of other long-lived assets on the presence of impairment indicators such as the future economic benefit of the assets, any historical or future profitability measurements, and other external market conditions or factors. We perform annual goodwill impairment tests for each of our reporting units containing goodwill during the fourth quarter of each year. Beginning in 2017, we changed our annual goodwill impairment testing date from December 31 to October 31 to better align the testing date with our financial planning process and alleviate resource constraints. We would not expect a materially different outcome in any given year as a result of testing on October 31 as compared to December 31. The carrying amount of a reporting unit's goodwill is considered not recoverable, and an impairment loss is recorded if the carrying amount of the reporting unit exceeds the reporting unit's fair value, as determined based on a combination of an income approach and a market approach. See Note 7 , Goodwill and Other Intangible Assets , for more information on our goodwill and other intangible assets. The carrying amount of tangible long-lived assets held and used is considered not recoverable if the carrying amount exceeds the undiscounted sum of cash flows expected to result from the use and eventual disposition of the asset. If the carrying amount is not recoverable, the impairment loss is measured as the excess of the asset's carrying amount over its fair value. Assets held for sale are evaluated for impairment at least annually and as impairment indicators are present. The carrying amount of assets held for sale is not recoverable if the carrying amount exceeds the fair value less estimated costs to sell the asset. An impairment loss is recorded for the excess of the asset’s carrying amount over the fair value less estimated costs to sell. Impairment losses are recorded in operating supplies and expenses in the consolidated statements of comprehensive income. Impairment losses were immaterial in 2018 , 2017 and 2016
Revenue Recognition	Revenue Recognition Through December 31, 2017 , we recorded transportation revenue at the time of delivery. Beginning in 2018, we implemented ASU 2014-09, Revenue from Contracts with Customers, which is codified as ASC 606 and replaces ASC 605, Revenue Recognition . With the adoption of ASC 606, we began recognizing revenue during the delivery period based on relative transit time in each reporting period, with expenses recognized as incurred. Accordingly, a portion of the total revenue that will be billed to the customer once a load is delivered is recognized in each reporting period based on the percentage of the freight pickup and delivery service that has been completed at the end of the reporting period. See Note 2 , Revenue Recognition , for more information on the adoption of ASC 606. When we use third-party carriers, we generally record revenues on the gross basis at amounts charged to our customers because we are the primary obligor, we are a principal in the transaction, we invoice our customers and retain all credit risks, and we maintain discretion over pricing. Additionally, we are responsible for selection of third-party transportation providers to the extent used to satisfy customer freight requirements. We record revenues net of pass-through taxes in our consolidated statements of comprehensive income. For the year ended December 31, 2018 , no customer accounted for more than 10% of our consolidated revenues. We had one customer who accounted for slightly more than 10% of our consolidated revenues in 2017. No customer accounted for more than 10% of our consolidated revenues in 2016.
Income Taxes	Income Taxes Income taxes are accounted for under the liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized as income or expense in the period that includes the enactment date. We record valuation allowances for deferred tax assets to the extent we believe these assets are not more likely than not to be realized through the reversal of existing taxable temporary differences, projected future taxable income, or tax-planning strategies. We record a liability for unrecognized tax benefits when the benefits of tax positions taken on a tax return are not more likely than not to be sustained upon audit. Interest and penalties related to uncertain tax positions are classified as income tax expense in the consolidated statements of comprehensive income.
Earnings Per Share	Earnings Per Share We compute basic earnings per share by dividing net earnings available to common stockholders by the actual weighted average number of common shares outstanding for the reporting period. Diluted earnings per share reflect the potential dilution that could occur if holders of unvested restricted and performance share units or options exercised or converted their holdings into common stock. Awards that would have an antidilutive impact are excluded from the calculation and have been deemed immaterial. As disclosed in Note 3 , IPO , our IPO of shares of Class B Common Stock was effective in April 2017. In connection with the offering, we subsequently sold additional shares of common stock.
Share-based Compensation	Share-based Compensation We have share-based compensation plans covering certain employees, including officers and directors. We account for share-based compensation using the fair value recognition provisions of current accounting standards for share-based payments. We grant restricted share units, restricted shares, performance share units, performance shares, and nonqualified stock options. We recognize compensation expense over the requisite service periods within each award. See Note 14 , Share-Based Compensation , for more information about our plans.
Claim Accruals	Claims Accruals We are self-insured for loss of and damage to our owned and leased revenue equipment. We purchase insurance coverage for a portion of expenses related to employee injuries, vehicular collisions, accidents, and cargo damage. Certain insurance arrangements include a level of self-insurance (deductible) coverage applicable to each claim. We have excess policies to limit our exposure to catastrophic claim costs. The amounts of self-insurance change from time to time based on measurement dates, policy expiration dates, and claim type. Our claims accrual policy for all self-insured claims is to recognize a liability at the time of the incident based on our analysis of the nature and severity of the claims and analyses provided by third-party claims administrators, as well as legal, economic, and regulatory factors. The ultimate cost of a claim develops over time as additional information regarding the nature, timing, and extent of damages claimed becomes available. Accordingly, we use an actuarial method to develop current claim information to derive an estimate of our ultimate claim liability. This process involves the use of loss-development factors based on our historical claims experience and includes a contractual premium adjustment factor, if applicable. In doing so, the recorded liability considers future claims growth and provides an allowance for incurred-but-not-reported claims. We do not discount our estimated losses. At December 31, 2018 and 2017 , we had an accrual of approximately $ 156.0 million and $ 147.2 million , respectively, for estimated claims net of reinsurance receivables. In addition, we are required to pay certain advanced deposits and monthly premiums. At December 31, 2018 and 2017 , we had an aggregate prepaid insurance asset of approximately $ 9.2 million and $7.9 million , respectively, which represented prefunded premiums and deposits.
Accounting Standards Issued But Not Yet Adopted	Accounting Standards Issued but Not Yet Adopted In August 2018, the FASB issued ASU 2018-15, Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, which aligns the capitalization requirements for implementation costs incurred in a hosting arrangement that is a service contract with the existing capitalization requirements for implementation costs incurred to develop or obtain internal-use software. ASU 2018-15 is effective for us as of January 1, 2020 with early adoption permitted. We currently cannot reasonably estimate the impact the adoption of this ASU will have on our consolidated financial statements. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement - Disclosure Requirements, which removes, modifies, and adds certain disclosure requirements for fair value measurements. ASU 2018-13 is effective for us January 1, 2020 with early adoption permitted. We are currently evaluating the impact the adoption of this ASU will have on our consolidated financial statements and do not believe the impact will be material. In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments , which requires companies to use a forward-looking, expected loss model to estimate credit losses on various types of financial assets and net investments in leases. It also requires additional disclosure related to credit quality of trade and other receivables, including information related to management’s estimate of credit allowances. ASU 2016-13 is effective for us January 1, 2020. We currently cannot reasonably estimate the impact the adoption of this ASU will have on our consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases, which amended authoritative guidance on leases and is codified in ASC 842. The amended guidance requires lessees to recognize most leases on their balance sheets as right-of-use assets along with corresponding lease liabilities. The new standard also requires new disclosures to help financial statement users better understand the amount, timing, and uncertainty of cash flows arising from leases. This guidance was effective for us January 1, 2019. In July 2018, the FASB issued additional authoritative guidance providing companies with the option to apply this ASU to new and existing leases within the scope of the guidance as of the beginning of the period of adoption. We elected this transition method of applying the new lease standard and recognized right-of-use assets, lease liabilities, and any cumulative-effect adjustments to the opening balance of retained earnings as of January 1, 2019. Prior period amounts will not be adjusted and will continue to be reported under the accounting standards in effect for those periods. Upon adoption of the new standard on January 1, 2019, we elected the package of practical expedients provided under the guidance. The practical expedient package applied to leases that commenced prior to adoption of the new standard and permitted companies not to reassess whether existing or expired contracts are or contain a lease, the lease classification, and any initial direct costs for any existing leases. The Company also elected the recognition exemption for equipment leases, which allows the Company to not recognize right-of-use assets and liabilities for leases with an initial term of 12 months or less. Additionally, the Company elected to take the practical expedient to include non-lease components as part of the right-of-use asset and lease liability. A cross-functional implementation team identified the Company's lease population, leveraged and expanded the use of our existing lease software to assist with the reporting and disclosure requirements under the standard, and abstracted and validated our lease information. The adoption of the standard added approximately $80 million in right-of-use assets and related lease obligations to our consolidated balance sheet for operating leases in which we were the lessee as of January 1, 2019. The adoption of this standard did not have a material impact on our consolidated statements of comprehensive income. Leasing activities in which we are the lessor in the transaction are also subject to ASC 842. As a lessor, adopting this standard did not have a material impact on our consolidated balance sheets but will add to both operating revenues and expenses in the consolidated statements of comprehensive income, as certain leases previously treated as direct financing leases will become sales-type leases.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Inventory Balances	The following table shows the components of our inventory balances as of December 31: (in millions) 2018 2017 Tractors and trailing equipment for sale or lease $ 48.1 $ 69.8 Replacement parts 11.4 11.8 Tires and other 1.3 1.5 Total $ 60.8 $ 83.1
Estimated Useful Lives	Generally, the estimated useful lives are as follows: 2018 Tractors 2 - 10 years Trailing equipment 6 - 20 years Other transportation equipment 4 - 5 years Buildings and improvements 5 - 25 years Other property 3 - 10 years Salvage values, when applicable, generally don't exceed 25% of original cost for tractors and trailing equipment and reflect any agreements with tractor suppliers for residual or trade-in values for certain new equipment. Gains and losses on the sale or other disposition of equipment are based on the difference between the proceeds received less costs to sell and the net book value of the assets disposed. Gains and losses are recognized at the time of the sale or disposition and are classified in operating supplies and expenses in the consolidated statements of comprehensive income.
Assets held for sale by segment	As of December 31, 2018 and 2017 , assets held for sale by segment were as follows: (in millions) 2018 2017 Truckload $ 19.5 $ 35.2 Intermodal 2.4 0.7 Total $ 21.9 $ 35.9

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Summary of Impact of Adoption of Accounting Standards	The changes relate to the recognition of transportation revenue over time rather than at delivery, as explained below under the Transportation heading. Revenue in transit and the related expenses are recorded within our Other segment, except for FTFM which is recorded within the Truckload segment. Year Ended December 31, 2018 Financial Statement Line Item (in millions) Under ASC 605 Adjustment As Reported Consolidated Statement of Comprehensive Income Operating revenues $ 4,977.6 $ (0.6 ) $ 4,977.0 Purchased transportation 1,965.2 0.7 1,965.9 Salaries, wages, and benefits 1,260.3 (0.9 ) 1,259.4 Total operating expenses 4,601.4 (0.2 ) 4,601.2 Income from operations 376.2 (0.4 ) 375.8 Provision for income taxes 364.6 — 364.6 Net income 269.3 (0.4 ) 268.9 Comprehensive income 268.3 (0.4 ) 267.9 December 31, 2018 Financial Statement Line Item (in millions) Under ASC 605 Adjustment As Reported Consolidated Balance Sheet Prepaid expenses and other current assets $ 59.8 $ 19.7 $ 79.5 Total current assets 1,304.6 19.7 1,324.3 Total assets 3,604.8 19.7 3,624.5 Other current liabilities 70.8 10.4 81.2 Total current liabilities 512.2 10.4 522.6 Deferred income taxes 448.2 2.4 450.6 Total noncurrent liabilities 967.2 2.4 969.6 Retained earnings 582.4 6.9 589.3 Total shareholders' equity 2,125.4 6.9 2,132.3 Total liabilities and shareholders' equity 3,604.8 19.7 3,624.5 Year Ended December 31, 2018 Financial Statement Line Item (in millions) Under ASC 605 Adjustment As Reported Consolidated Statement of Cash Flows Operating Cash Flows Net income $ 269.3 $ (0.4 ) $ 268.9 Change in: Other assets (8.7 ) (0.3 ) (9.0 ) Change in: Payables 3.0 — 3.0 Change in: Other liabilities 11.0 0.7 11.7
Disaggregation of Revenue	The following table breaks down our revenues by type of service, and each type of service is further described below. Year Ended December 31, Disaggregated Revenues ( in millions ) 2018 2017 Transportation $ 4,589.7 $ 4,012.4 Logistics management 228.3 220.2 Other 159.0 151.0 Total operating revenues $ 4,977.0 $ 4,383.6
Remaining Performance Obligations	The following table provides information related to transactions and expected timing of revenue recognition related to performance obligations that are fixed in nature and relate to contracts with terms greater than one year. Remaining Performance Obligations (in millions) December 31, 2018 Expected to be recognized within one year Transportation $ 5.6 Logistics Management 17.4 Expected to be recognized after one year Transportation 2.2 Logistics Management 4.0 Total $ 29.2
Contract Balances	The following table provides information related to contract balances associated with our contracts with customers as of the dates shown. Contract Balances ( in millions ) December 31, 2018 January 1, 2018 Other current assets - Contract assets $ 21.7 $ 22.2 Other current liabilities - Contract liabilities — —
Capitalized Contract Cost	The following table presents the amounts capitalized for contract fulfillment costs as of the dates shown. (in millions) December 31, 2018 January 1, 2018 Capitalized contract fulfillment costs $ 5.0 $ 3.7
Amortization of Contract Fulfillment Costs	Amortization of capitalized contract fulfillment costs was as shown: Year Ended December 31, (in millions) 2018 2017 Amortization of contract fulfillment costs $ 2.5 $ 2.0

Acquisition (Tables)

Acquisition (Tables) - WSL	12 Months Ended
	Dec. 31, 2018
Business Acquisition [Line Items]
Schedule of Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed	(in millions) Recognized amounts of identifiable assets acquired and liabilities assumed As of June 1, 2016 Cash $ 1.3 Receivables 16.2 Inventories 0.5 Prepaid expenses and other current assets 4.4 Property and equipment 81.8 Capitalized software and other noncurrent assets 5.8 Intangible assets 10.9 Goodwill 138.2 Total assets acquired 259.1 Payables assumed 7.8 Accrued liabilities assumed 5.3 Current maturities of debt and capital lease obligations assumed 47.7 Debt and capital lease obligations assumed 46.2 Other noncurrent liabilities assumed 1.7 Fair value of total consideration transferred $ 150.4
Schedule of Pro Forma Condensed Combined Financial Information	The following unaudited pro forma condensed combined financial information presents our results as if we had acquired WSL on January 1, 2016. (in millions, except per share data) Year Ended December 31, 2016 Pro forma net sales $ 4,119.3 Pro forma net income 155.0 Basic earnings per share as reported 1.00 Pro forma basic earnings per share 0.99 Diluted earnings per share as reported 1.00 Pro forma diluted earnings per share 0.99

Fair Value Fair Value (Tables)

Fair Value Fair Value (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	The following table sets forth a reconciliation of changes in the fair value of the contingent consideration: (in millions) 2018 2017 Beginning balance $ — $ 13.5 Change in fair value — (13.5 ) Ending balance $ — $ —
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments	The table below presents the carrying value of our debt portfolio along with the fair value of a fixed-rate debt portfolio with similar terms and maturities, which is based on borrowing rates available to us in the applicable year. This valuation used Level 2 inputs. December 31, 2018 December 31, 2017 (in millions) Carrying Amount Fair Value Carrying Amount Fair Value Fixed-rate debt portfolio $ 405.0 $ 398.4 $ 429.8 $ 432.4

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2018
Investments Schedule [Abstract]
Schedule of Marketable Securities	The following table presents the values of our marketable securities as of the dates shown. December 31, 2018 December 31, 2017 (in millions) Amortized Cost Fair Value Amortized Cost Fair Value Zero coupon bonds $ 3.9 $ 3.9 $ 3.8 $ 3.9 U.S. treasury and government agencies 20.0 19.8 6.0 6.0 Asset-backed securities 0.1 0.1 0.3 0.3 Corporate debt securities 15.1 15.0 9.1 9.2 State and municipal bonds 12.5 12.5 22.7 22.2 Total marketable securities $ 51.6 $ 51.3 $ 41.9 $ 41.6

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Changes in Carrying Amount of Goodwill	The following table shows changes to our goodwill balances by segment during the years ended December 31, 2018 and December 31, 2017 . (in millions) Truckload Logistics Other Total Balance at December 31, 2016 $ 138.2 $ 14.2 $ 11.6 $ 164.0 Foreign currency translation — — 0.8 0.8 Balance at December 31, 2017 138.2 14.2 12.4 164.8 Goodwill impairment charge — — (2.0 ) (2.0 ) Foreign currency translation — — (0.6 ) (0.6 ) Balance at December 31, 2018 $ 138.2 $ 14.2 $ 9.8 $ 162.2
Estimated Useful Lives	The identifiable intangible assets other than goodwill listed below are included in capitalized software and other noncurrent assets on the consolidated balance sheets. Our customer lists and trade names are amortized over weighted-average amortization periods of ten and three years, respectively. December 31, 2018 December 31, 2017 (in millions) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Customer lists $ 10.5 $ 3.5 $ 7.0 $ 10.5 $ 2.5 $ 8.0 Trade names 1.4 1.2 0.2 1.4 0.7 0.7 Total intangible assets $ 11.9 $ 4.7 $ 7.2 $ 11.9 $ 3.2 $ 8.7
Schedule Estimated Future Amortization Expense	Estimated future amortization expense related to intangible assets is as follows (in millions): 2019 $ 1.1 2020 1.0 2021 1.0 2022 1.0 2023 1.0 2024 and thereafter 2.1 Total $ 7.2

Debt and Credit Facilities (Tab

Debt and Credit Facilities (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Summary of Debt	As of December 31, 2018 and 2017 , debt included the following: (in millions) December 31, 2018 December 31, 2017 Unsecured senior notes: principal payable at maturities ranging from 2019 through 2025; interest payable in semiannual installments through the same time frame; weighted-average interest rate of 3.36% for both 2018 and 2017 $ 400.0 $ 400.0 Equipment financing notes: principal and interest payable in monthly installments through 2019; weighted average interest rate of 3.72% and 3.76% for 2018 and 2017, respectively 5.0 29.8 Total principal outstanding 405.0 429.8 Current maturities of debt (45.0 ) (15.2 ) Debt issuance costs (0.6 ) (0.9 ) Long-term debt $ 359.4 $ 413.7
Schedule of Maturities of Long-term Debt	Scheduled principal payments of debt subsequent to December 31, 2018 are as follows: Years ending December 31, (in millions) 2019 $ 45.0 2020 55.0 2021 40.0 2022 60.0 2023 70.0 2024 and thereafter 135.0 Total $ 405.0

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2018
Leases [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	At December 31, 2018 , scheduled future minimum lease payments under operating leases having initial or remaining noncancelable lease terms of more than one year and capital leases were as follows: (in millions) Operating Leases Capital Leases 2019 $ 35.8 $ 6.9 2020 25.7 0.2 2021 14.9 — 2022 8.4 — 2023 6.8 — 2024 and thereafter 12.7 — Total $ 104.3 7.1 Amount representing interest (0.2 ) Present value of minimum lease payments 6.9 Current maturities (6.7 ) Long-term capital lease obligations $ 0.2
Schedule of Future Minimum Lease Payments for Capital Leases	At December 31, 2018 , scheduled future minimum lease payments under operating leases having initial or remaining noncancelable lease terms of more than one year and capital leases were as follows: (in millions) Operating Leases Capital Leases 2019 $ 35.8 $ 6.9 2020 25.7 0.2 2021 14.9 — 2022 8.4 — 2023 6.8 — 2024 and thereafter 12.7 — Total $ 104.3 7.1 Amount representing interest (0.2 ) Present value of minimum lease payments 6.9 Current maturities (6.7 ) Long-term capital lease obligations $ 0.2
Schedule of Capital Leased Assets	The consolidated balance sheets include assets acquired under capital leases as components of property and equipment as of December 31, 2018 and 2017 , as follows: (in millions) 2018 2017 Transportation equipment $ 19.9 $ 25.0 Real property 0.8 0.8 Other property 0.6 0.6 Accumulated amortization (11.2 ) (12.6 ) Total $ 10.1 $ 13.8
Schedule of Investment in Lease Receivables	As of December 31, 2018 and 2017 , the investment in lease receivables was as follows: (in millions) 2018 2017 Future minimum payments to be received on leases $ 140.0 $ 141.2 Guaranteed residual lease values 151.0 130.7 Total minimum lease payments to be received 291.0 271.9 Unearned income (28.7 ) (28.1 ) Net investment in leases 262.3 243.8 Current maturities of lease receivables 129.6 106.6 Less—allowance for doubtful accounts (0.5 ) (1.7 ) Current portion of lease receivables—net of allowance 129.1 104.9 Lease receivables—noncurrent $ 133.2 $ 138.9
Schedule of Principal Amounts to be Received on Lease Receivables	The principal amounts to be received on lease receivables as of December 31, 2018 , were as follows: Years ending December 31 (in millions) 2019 $ 149.0 2020 112.7 2021 29.0 2022 0.3 2023 — 2024 and thereafter — Total $ 291.0

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	The components of the provision for income taxes as of December 31, 2018 , 2017 and 2016 , were as follows: (in millions) 2018 2017 2016 Current: Federal $ 21.7 $ 19.3 $ 24.4 State and other 11.8 5.6 7.5 33.5 24.9 31.9 Deferred: Federal 54.2 71.4 71.2 State and other 6.7 6.7 5.6 Impact of the Tax Cuts and Jobs Act 1.3 (229.5 ) — 62.2 (151.4 ) 76.8 Total provision for (benefit from) income taxes $ 95.7 $ (126.5 ) $ 108.7
Schedule of Effective Income Tax Rate Reconciliation	The provision for income taxes as of December 31, 2018 , 2017 , and 2016 differed from the amounts computed using the federal statutory rates in effect of 21% for December 31, 2018 and 35% for December 31, 2017 and 2016 , as follows: 2018 2017 2016 (in millions, except percentages) Dollar Impact Rate Dollar Impact Rate Dollar Impact Rate Income tax at federal statutory rate $ 76.6 21.0 % $ 92.2 35.0 % $ 93.0 35.0 % State tax, net of federal effect 15.4 4.2 % 8.6 3.3 % 10.5 3.9 % Nondeductible meals and entertainment 2.1 0.6 % 3.4 1.3 % 3.4 1.3 % Impact of the Tax Cuts and Jobs Act 1.3 0.3 % (229.5 ) (87.1 )% — — Other, net 0.3 0.1 % (1.2 ) (0.5 )% 1.8 0.7 % Total provision for (benefit from) income taxes $ 95.7 26.2 % $ (126.5 ) (48.0 )% $ 108.7 40.9 %
Schedule of Deferred Tax Assets and Liabilities	The components of the net deferred tax liability included in deferred income taxes in the consolidated balance sheets as of December 31, 2018 and 2017 , were as follows: (in millions) 2018 2017 Deferred tax assets: Allowances for doubtful accounts $ 1.1 $ 1.1 Compensation and employee benefits 14.7 15.6 Insurance and claims accruals 2.6 2.8 State net operating losses and credit carryforwards 18.2 17.7 Other 5.0 4.0 Total gross deferred tax assets 41.6 41.2 Valuation allowance (5.8 ) (4.4 ) Total deferred tax assets, net of valuation allowance 35.8 36.8 Deferred tax liabilities: Property and equipment 466.5 410.8 Prepaid expenses 4.3 3.6 Intangibles 11.1 8.7 Other 4.5 0.3 Total gross deferred tax liabilities 486.4 423.4 Net deferred tax liability $ 450.6 $ 386.6
Schedule of Unrecognized Tax Benefits Roll Forward	As of December 31, 2018 , 2017 , and 2016 , a reconciliation of the beginning and ending amount of unrecognized tax benefits, which is recorded as other noncurrent liabilities in the consolidated balance sheets, is as follows: (in millions) 2018 2017 2016 Gross unrecognized tax benefits - beginning of year $ 2.8 $ 2.4 $ 2.0 Gross increases - tax positions related to current year 0.8 0.4 0.5 Gross decreases - tax positions taken in prior years — — (0.1 ) Lapse of statutes (0.3 ) — — Gross unrecognized tax benefits - end of year $ 3.3 $ 2.8 $ 2.4

Temporary Equity (Tables)

Temporary Equity (Tables)	12 Months Ended
	Dec. 31, 2018
Temporary Equity Disclosure [Abstract]
Temporary Equity	The following table shows changes to temporary equity during the year ended December 31, 2017 . Class A Redeemable Common Shares Class B Redeemable Common Shares Accumulated Earnings Accumulated Other Comprehensive Income (in millions) Shares Amount Shares Amount Total Balance—December 31, 2016 83.0 $ 563.2 73.3 $ 497.2 $ 125.1 $ 0.9 $ 1,186.4 Net income — — — — 22.6 — 22.6 Other comprehensive income — — — — — — — Dividends declared at $0.05 per share — — — — (7.8 ) — (7.8 ) Change in redemption value of redeemable common shares — 67.3 — 59.3 (126.6 ) — — Transfer from temporary equity to common equity (83.0 ) (630.5 ) (73.3 ) (556.5 ) (13.3 ) (0.9 ) (1,201.2 ) Balance—December 31, 2017 — $ — — $ — $ — $ — $ —

Common Equity (Tables)

Common Equity (Tables)	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Calculation of Basic and Diluted Earnings Per Share	Year Ended December 31, (in millions, except per share data) 2018 2017 2016 Numerator: Net income available to common shareholders $ 268.9 $ 389.9 $ 156.9 Denominator: Weighted average common shares issued and outstanding 177.0 171.1 156.6 Effect of dilutive restricted share units 0.2 0.2 0.2 Weighted average diluted common shares issued and outstanding 177.2 171.3 156.8 Basic earnings per common share $ 1.52 $ 2.28 $ 1.00 Diluted earnings per common share $ 1.52 $ 2.28 $ 1.00

Share-based Compensation (Table

Share-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of components of share-based compensation program expense	The following table summarizes the components of our share-based compensation program expense: (in millions) Year Ended December 31, 2018 2017 2016 Restricted Shares and RSUs $ 3.1 $ 1.5 $ — Pre-IPO Restricted Shares 0.9 1.9 2.2 Performance Shares and PSUs 5.5 1.2 — Nonqualified Stock Options 1.4 0.6 — Share-based compensation expense $ 10.9 $ 5.2 $ 2.2 Related tax benefit $ 2.8 $ 2.0 $ 0.9
Schedule of restricted shares and RSU's activity	A portion of the restricted shares relate to a one-time 2018 grant, which vests 50% after a five -year period, with the remaining 50% vesting after a six -year period after the grant date, subject to continued employment through the vesting date. Dividend equivalents equal to dividends paid on our common shares during the vesting period are tracked and accumulated for each restricted share. The dividend equivalents are distributed to participants in cash consistent with the date the awards vest. Restricted Shares and RSUs Number of Awards Weighted Average Grant Date Fair Value Unvested at December 31, 2016 — $ — Granted 246,516 19.00 Vested — — Forfeited (6,500 ) 19.00 Unvested at December 31, 2017 240,016 19.00 Granted 229,272 26.82 Vested (74,828 ) 19.00 Forfeited (24,983 ) 21.26 Unvested at December 31, 2018 369,477 $ 23.70 Prior to our IPO, we granted restricted shares of Class B Common Stock. Shares included in the pre-IPO restricted share grants vest ratably over a three -year period. Cash dividends are not paid on the unvested pre-IPO restricted shares, nor do they accumulate during the vesting period. Pre-IPO Restricted Shares Number of Awards Weighted Average Grant Date Fair Value Unvested at January 1, 2016 798,960 $ 5.63 Granted 386,370 6.78 Vested (398,220 ) 5.42 Forfeited (9,900 ) 6.17 Unvested at December 31, 2016 777,210 6.31 Granted — — Vested (621,722 ) 7.59 Forfeited (a) (3,289 ) 19.00 Unvested at December 31, 2017 152,199 19.00 Granted — — Vested (101,643 ) 19.00 Forfeited (6,225 ) 19.00 Unvested at December 31, 2018 44,331 $ 19.00 (a) In April 2017, unvested restricted shares were adjusted to the IPO share price of $19.00 .
Schedule of performance shares and PSU's activity	The dividend equivalents are forfeitable and are distributed to participants in cash consistent with the date the awards vest. Performance Shares and PSUs Number of Awards Weighted Average Grant Date Fair Value Unvested at December 31, 2016 — $ — Granted 396,201 19.00 Vested — — Forfeited (4,660 ) 19.00 Unvested at December 31, 2017 391,541 19.00 Granted 303,228 26.78 Vested — — Forfeited (56,390 ) 19.65 Unvested at December 31, 2018 638,379 $ 22.64
Schedule of nonqualified stock options activity	The options granted under the Plan have an exercise price equal to the fair market value of the underlying stock at the date of grant and vest ratably over a four -year period, with the first 25% of the grant becoming exercisable approximately one year after the date of grant. The options expire ten years from the date of grant. Nonqualified Stock Options Outstanding Number of Awards Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value (1) (In years) (In thousands) Outstanding at December 31, 2016 — $ — — $ — Granted 229,620 19.00 — — Exercised (2) — — — — Forfeited — — — — Outstanding at December 31, 2017 229,620 $ 19.00 9.3 $ 2,195 Granted 173,024 26.74 — — Exercised (2) (8,410 ) 19.00 — 67 Forfeited (25,230 ) 19.00 — — Outstanding at December 31, 2018 369,004 $ 22.63 8.7 $ — Exercisable as of: December 31, 2017 — — — — December 31, 2018 48,995 $ 19.00 8.3 $ — (1) The aggregate intrinsic value was computed using the closing share price on December 31, 2018 of $ 18.67 and on December 29, 2017 of $ 28.56 , as applicable. (2) Cash received upon exercise of stock options was $0.2 million in 2018 and $0 in 2017. Unvested Nonqualified Stock Options Number of Awards Weighted Average Grant Date Fair Value Unvested at December 31, 2016 — $ — Granted 229,620 6.37 Vested — — Forfeited — — Unvested at December 31, 2017 229,620 6.37 Granted 173,024 8.96 Vested (57,405 ) 6.37 Forfeited (25,230 ) 6.37 Unvested at December 31, 2018 320,009 $ 7.77
Schedule of assumptions used in calculating value of stock options	Assumptions used in calculating the Black-Scholes value of options granted during 2018 and 2017 were as follows: Year Ended December 31, 2018 Year Ended December 31, 2017 Weighted-average Black-Scholes value $ 8.96 $ 6.37 Black-Scholes Assumptions: Expected term 6.25 years 6.25 years Expected volatility 32.2 % 35.0 % Expected dividend yield 0.9 % 1.1 % Risk-free interest rate 2.8 % 2.2 %

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Summary of Segment Reporting Information	The following tables summarize our segment information. Intersegment revenues were immaterial for all segments, with the exception of Other, which included revenues from insurance premiums charged to other segments for workers’ compensation, auto, and other types of insurance. Intersegment revenues included in Other revenues below were $82.7 million, $78.4 million and $54.4 million for the years ended December 31, 2018 , 2017 , and 2016 respectively. Revenues by Segment (in millions) Year Ended December 31, 2018 2017 2016 Truckload $ 2,268.0 $ 2,187.4 $ 2,091.0 Intermodal 953.5 779.9 757.5 Logistics 1,024.6 834.3 737.7 Other 322.0 293.6 240.5 Fuel surcharge 522.8 386.3 294.0 Inter-segment eliminations (113.9 ) (97.9 ) (75.0 ) Operating revenues $ 4,977.0 $ 4,383.6 $ 4,045.7 Income (Loss) from Operations by Segment (in millions) Year Ended December 31, 2018 2017 2016 Truckload $ 240.5 $ 196.2 $ 221.1 Intermodal 130.2 52.3 46.1 Logistics 47.4 34.2 30.7 Other (42.3 ) (2.4 ) (7.5 ) Income from operations $ 375.8 $ 280.3 $ 290.4 Depreciation and Amortization Expense by Segment (in millions) Year Ended December 31, 2018 2017 2015 Truckload $ 211.0 $ 205.9 $ 192.6 Intermodal 39.8 34.5 30.9 Logistics 0.4 0.4 0.4 Other 40.1 38.2 42.1 Depreciation and amortization expense $ 291.3 $ 279.0 $ 266.0

Quarterly Results of Operatio_2

Quarterly Results of Operations (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information	(in millions, except per share amounts)* First Quarter Second Quarter Third Quarter Fourth Quarter Full Year 2018 Operating revenues $ 1,139.0 $ 1,236.3 $ 1,280.1 $ 1,321.6 $ 4,977.0 Income from operations 67.6 91.7 97.9 118.6 375.8 Net income 47.6 65.8 70.7 84.8 268.9 Basic earnings per share 0.27 0.37 0.40 0.48 1.52 Diluted earnings per share 0.27 0.37 0.40 0.48 1.52 2017 Operating revenues $ 1,006.4 $ 1,075.2 $ 1,110.8 $ 1,191.2 $ 4,383.6 Income from operations 43.5 79.0 64.1 93.7 280.3 Net income** 22.6 46.5 36.9 283.9 389.9 Basic earnings per share** 0.14 0.27 0.21 1.60 2.28 Diluted earnings per share** 0.14 0.27 0.21 1.60 2.28

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Inventory (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Inventory [Line Items]
Inventory, Total	$ 60.8	$ 83.1
Tractors and trailing equipment for sale or lease
Inventory [Line Items]
Inventory, Total	48.1	69.8
Replacement parts
Inventory [Line Items]
Inventory, Total	11.4	11.8
Tires and other
Inventory [Line Items]
Inventory, Total	$ 1.3	$ 1.5

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Investments in Marketable Equity Securities (Details)	12 Months Ended
	Dec. 31, 2018
Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Marketable securities maturity term	2 months
Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Marketable securities maturity term	81 months

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Property, Plant and Equipment (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Tractors | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	2 years
Tractors | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life		10 years
Salvage value, percentage	25.00%
Trailing equipment | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	6 years
Trailing equipment | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life		20 years
Salvage value, percentage	25.00%
Other transportation equipment | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	4 years
Other transportation equipment | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life		5 years
Buildings and improvements | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Buildings and improvements | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life		25 years
Other property | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3 years
Other property | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life		10 years

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Assets Held for Sale (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Long Lived Assets Held-for-sale [Line Items]
Assets Held for Sale, Total	$ 21.9	$ 35.9
Truckload
Long Lived Assets Held-for-sale [Line Items]
Assets Held for Sale, Total	19.5	35.2
Intermodal
Long Lived Assets Held-for-sale [Line Items]
Assets Held for Sale, Total	$ 2.4	$ 0.7

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Asset Impairment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Asset Impairment Charges	$ 0	$ 0	$ 0

Summary of Significant Accoun_9

Summary of Significant Accounting Policies - Claims Accruals (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Accrued Insurance	$ 156	$ 147.2
Prepaid Insurance	$ 9.2	$ 7.9

Summary of Significant Accou_10

Summary of Significant Accounting Policies - Accounting Standards Issued But Not Yet Adopted (Details) - Scenario, Forecast - Accounting Standards Update 2016-02 $ in Millions	Jan. 01, 2019USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use asset added	$ 80
Related lease obligations	$ 80

Revenue Recognition Summary of

Revenue Recognition Summary of Impact of Adoption of Accounting Standards (Details) - USD ($) $ in Millions	3 Months Ended								9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating revenues	$ 1,321.6	$ 1,280.1	$ 1,236.3	$ 1,139	$ 1,191.2	$ 1,110.8	$ 1,075.2	$ 1,006.4		$ 4,977	$ 4,383.6	$ 4,045.7
Purchased transportation										1,965.9	1,605.3	1,466
Salaries, wages, and benefits										1,259.4	1,223.5	1,129.3
Total operating expenses										4,601.2	4,103.3	3,755.3
Income from operations	118.6	97.9	91.7	67.6	93.7	64.1	79	43.5		375.8	280.3	290.4
Provision for income taxes										364.6	263.4	265.6
Net income	84.8	$ 70.7	$ 65.8	$ 47.6	283.9	$ 36.9	$ 46.5	$ 22.6	$ 367.4	268.9	389.9	156.9
Comprehensive income										267.9	389	157.4
Prepaid expenses and other current assets	79.5				75.6				75.6	79.5	75.6
Total current assets	1,324.3				1,094				1,094	1,324.3	1,094
Total Assets	3,624.5				3,330.5				3,330.5	3,624.5	3,330.5
Other current liabilities	81.2				69.6				69.6	81.2	69.6
Total current liabilities	522.6				462				462	522.6	462
Deferred income taxes	450.6									450.6
Total noncurrent liabilities	969.6				978.3				978.3	969.6	978.3
Retained earnings	589.3				355.6				355.6	589.3	355.6
Total shareholders' equity	2,132.3				1,890.2				1,890.2	2,132.3	1,890.2	0	$ 0
Total liabilities and shareholders' equity	3,624.5				$ 3,330.5				$ 3,330.5	3,624.5	3,330.5
Change in: Other assets										9	(1.4)	4.9
Payables										3	16	(0.6)
Other liabilities										11.7	$ (2)	$ (37.4)
Balances under ASC 605 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating revenues										4,977.6
Purchased transportation										1,965.2
Salaries, wages, and benefits										1,260.3
Total operating expenses										4,601.4
Income from operations										376.2
Provision for income taxes										364.6
Net income										269.3
Comprehensive income										268.3
Prepaid expenses and other current assets	59.8									59.8
Total current assets	1,304.6									1,304.6
Total Assets	3,604.8									3,604.8
Other current liabilities	70.8									70.8
Total current liabilities	512.2									512.2
Deferred income taxes	448.2									448.2
Total noncurrent liabilities	967.2									967.2
Retained earnings	582.4									582.4
Total shareholders' equity	2,125.4									2,125.4
Total liabilities and shareholders' equity	3,604.8									3,604.8
Change in: Other assets										(8.7)
Payables										3
Other liabilities										11
Effect on line items of ASC 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating revenues										(0.6)
Purchased transportation										0.7
Salaries, wages, and benefits										(0.9)
Total operating expenses										(0.2)
Income from operations										(0.4)
Provision for income taxes										0
Net income										(0.4)
Comprehensive income										(0.4)
Prepaid expenses and other current assets	19.7									19.7
Total current assets	19.7									19.7
Total Assets	19.7									19.7
Other current liabilities	10.4									10.4
Total current liabilities	10.4									10.4
Deferred income taxes	2.4									2.4
Total noncurrent liabilities	2.4									2.4
Retained earnings	6.9									6.9
Total shareholders' equity	6.9									6.9
Total liabilities and shareholders' equity	$ 19.7									19.7
Change in: Other assets										(0.3)
Payables										0
Other liabilities										$ 0.7

Revenue Recognition Disaggregat

Revenue Recognition Disaggregation of Revenues (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Operating revenues	$ 1,321.6	$ 1,280.1	$ 1,236.3	$ 1,139	$ 1,191.2	$ 1,110.8	$ 1,075.2	$ 1,006.4	$ 4,977	$ 4,383.6	$ 4,045.7
Transportation [Member]
Disaggregation of Revenue [Line Items]
Operating revenues									4,589.7	4,012.4
Logistics Management [Member]
Disaggregation of Revenue [Line Items]
Operating revenues									228.3	220.2
Other [Member]
Disaggregation of Revenue [Line Items]
Operating revenues									$ 159	$ 151

Revenue Recognition Revenue, Re

Revenue Recognition Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction (Details) $ in Millions	Dec. 31, 2018USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations (in millions)	$ 29.2
Transportation [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations (in millions)	5.6
Transportation [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations (in millions)	2.2
Logistics Management [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations (in millions)	17.4
Logistics Management [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations (in millions)	$ 4

Revenue Recognition Contract wi

Revenue Recognition Contract with Customer, Asset and Liability (Details) - USD ($) $ in Millions	Dec. 31, 2018	Jan. 01, 2018
Revenue from Contract with Customer [Abstract]
Contract with Customer, Asset, Net	$ 21.7	$ 22.2
Contract with Customer, Liability	$ 0	$ 0

Revenue Recognition Capitalized

Revenue Recognition Capitalized Contract Cost (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Capitalized contract fulfillment costs	$ 5	$ 3.7

Revenue Recognition Amortizatio

Revenue Recognition Amortization of Contract Fulfillment Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Amortization of contract fulfillment costs	$ 2.5	$ 2

Revenue Recognition Initial App

Revenue Recognition Initial Application Period Cumulative Effect Adjustment (Details) $ in Millions	Jan. 01, 2018USD ($)
Revenue from Contract with Customer [Abstract]
Cumulative Effect on Retained Earnings, Net of Tax	$ 7.3

IPO (Details)

IPO (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	May 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Subsidiary, Sale of Stock [Line Items]
Proceeds from IPO, net of issuance costs		$ 0	$ 340.6	$ 0
IPO | Class B Common Stock
Subsidiary, Sale of Stock [Line Items]
Share issued during the period (shares)	20,145,000
Share issued, (price per share)	$ 19
Proceeds from IPO, gross	$ 382.7
Expenses related to the offering	42.1
Proceeds from IPO, net of issuance costs	$ 340.6

Acquisition - Additional Inform

Acquisition - Additional Information (Details) - WSL $ in Millions	Jun. 30, 2018USD ($)	Jun. 01, 2017	Jun. 01, 2016USD ($)payment	Jun. 30, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2018USD ($)
Business Acquisition [Line Items]
Percentage of voting interest acquired			100.00%
Purchase price of acquisition			$ 150.4
Percentage of goodwill deductible for income tax purpose			100.00%
Cash paid at closing			$ 79.5
Initial guaranteed payment				$ 19.7
Guaranteed payments						$ 18.7
Aggregate payment of contingent consideration			$ 40
Acquisition-related costs					$ 1.4
Former Owners
Business Acquisition [Line Items]
Cash payments	$ 20
Number of payments | payment			3
Contingent consideration period		3 years	3 years
Former Owners | Minimum
Business Acquisition [Line Items]
Credit adjusted discount rate on cash payment			1.00%
Former Owners | Maximum
Business Acquisition [Line Items]
Credit adjusted discount rate on cash payment			3.00%

Acquisition - Schedule of Recog

Acquisition - Schedule of Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions	Jun. 01, 2016	Dec. 31, 2018	Dec. 31, 2017
Recognized amounts of identifiable assets acquired and liabilities assumed
Goodwill		$ 162.2	$ 164.8
WSL
Recognized amounts of identifiable assets acquired and liabilities assumed
Cash	$ 1.3
Receivables	16.2
Inventories	0.5
Prepaid expenses and other current assets	4.4
Property and equipment	81.8
Capitalized software and other noncurrent assets	5.8
Intangible assets	10.9
Goodwill	138.2
Total assets acquired	259.1
Payables assumed	7.8
Accrued liabilities assumed	5.3
Current maturities of debt and capital lease obligations assumed	47.7
Debt and capital lease obligations assumed	46.2
Other noncurrent liabilities assumed	1.7
Fair value of total consideration transferred	$ 150.4

Acquisition - Schedule of Pro F

Acquisition - Schedule of Pro Forma Condensed Combined Financial Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Combination Segment Allocation [Line Items]
Basic earnings per share as reported (usd per share)	$ 0.48	$ 0.40	$ 0.37	$ 0.27	$ 1.60	$ 0.21	$ 0.27	$ 0.14	$ 1.52	$ 2.28	$ 1
Diluted earnings per share as reported (usd per share)	$ 0.48	$ 0.40	$ 0.37	$ 0.27	$ 1.60	$ 0.21	$ 0.27	$ 0.14	$ 1.52	$ 2.28	$ 1
WSL
Business Combination Segment Allocation [Line Items]
Pro forma net sales											$ 4,119.3
Pro forma net income											$ 155
Basic earnings per share as reported (usd per share)											$ 1
Pro forma basic earnings per share (usd per share)											0.99
Diluted earnings per share as reported (usd per share)											1
Pro forma diluted earnings per share (usd per share)											$ 0.99

Fair Value - Additional Informa

Fair Value - Additional Information (Details) - USD ($)	Jun. 01, 2017	Jun. 01, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers between fair value hierarchy levels			$ 0
WSL | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration			$ 0	$ 0	$ 13,500,000
Former Owners | WSL
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration period	3 years	3 years

Fair Value - Liability Rollforw

Fair Value - Liability Rollforward (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Change in fair value	$ 0	$ 13,500,000	$ 0
WSL | Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	0	13,500,000
Change in fair value	0	(13,500,000)
Ending balance	$ 0	$ 0	$ 13,500,000

Fair Value Far Value - Other Fi

Fair Value Far Value - Other Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Total principal outstanding	$ 405	$ 429.8
Fair Value	$ 398.4	$ 432.4

Investments - Schedule of Marke

Investments - Schedule of Marketable Securities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent		30.00%
Available-for-sale Securities, Amortized Cost Basis	$ 51.6		$ 41.9
Available-for-sale Securities	51.3		41.6
Platform Science investment	3.5
Zero coupon bonds
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	3.9		3.8
Available-for-sale Securities	3.9		3.9
U.S. treasury and government agencies
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	20		6
Available-for-sale Securities	19.8		6
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	0.1		0.3
Available-for-sale Securities	0.1		0.3
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	15.1		9.1
Available-for-sale Securities	15		9.2
State and municipal bonds
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	12.5		22.7
Available-for-sale Securities	$ 12.5		$ 22.2

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets - Schedule of Changes in Carrying Amount of Goodwill (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Goodwill, Beginning Balance		$ 164.8	$ 164
Goodwill, Impairment Loss	$ (2)	(2)	0	$ 0
Foreign currency translation		(0.6)	0.8
Goodwill, Ending Balance	162.2	162.2	164.8	164
Truckload
Goodwill [Roll Forward]
Goodwill, Beginning Balance		138.2	138.2
Goodwill, Impairment Loss		0
Foreign currency translation		0	0
Goodwill, Ending Balance	138.2	138.2	138.2	138.2
Logistics
Goodwill [Roll Forward]
Goodwill, Beginning Balance		14.2	14.2
Goodwill, Impairment Loss		0
Foreign currency translation		0	0
Goodwill, Ending Balance	14.2	14.2	14.2	14.2
Other
Goodwill [Roll Forward]
Goodwill, Beginning Balance		12.4	11.6
Goodwill, Impairment Loss		(2)
Foreign currency translation		(0.6)	0.8
Goodwill, Ending Balance	$ 9.8	$ 9.8	$ 12.4	$ 11.6

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Schedule of Identifiable Intangible Assets Other Than Goodwill (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 11.9	$ 11.9
Accumulated Amortization	4.7	3.2
Net Carrying Amount	7.2	8.7
Customer lists
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	10.5	10.5
Accumulated Amortization	3.5	2.5
Net Carrying Amount	7	8
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1.4	1.4
Accumulated Amortization	1.2	0.7
Net Carrying Amount	$ 0.2	$ 0.7

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Accumulated goodwill impairment charge	$ 8	$ 8	$ 6
Goodwill impairment charge	$ 2	2	0	$ 0
Amortization expense for intangible assets		$ 1.4	$ 1.5	$ 0.9
Maximum
Finite-Lived Intangible Assets [Line Items]
Weighted-average amortization periods		10 years
Minimum
Finite-Lived Intangible Assets [Line Items]
Weighted-average amortization periods		3 years

Goodwill and Other Intangible_6

Goodwill and Other Intangible Assets - Schedule Estimated Future Amortization Expense (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule
2,019	$ 1.1
2,020	1
2,021	1
2,022	1
2,023	1
2024 and thereafter	2.1
Net Carrying Amount	$ 7.2	$ 8.7

Debt and Credit Facilities - Su

Debt and Credit Facilities - Summary of Debt (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Total principal outstanding	$ 405	$ 429.8
Current maturities of debt	(45)	(15.2)
Debt issuance costs	(0.6)	(0.9)
Long-term debt	359.4	413.7
Unsecured Senior Notes
Debt Instrument [Line Items]
Total principal outstanding	$ 400	$ 400
Maturity year	2,025
Weighted-average interest rate	3.36%	3.36%
Equipment Financing Notes
Debt Instrument [Line Items]
Total principal outstanding	$ 5	$ 29.8
Maturity year	2,019
Weighted-average interest rate	3.72%	3.76%

Debt and Credit Facilities - Sc

Debt and Credit Facilities - Schedule of Debt Maturities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
2,019	$ 45
2,020	55
2,021	40
2,022	60
2,023	70
2024 and thereafter	135
Total	$ 405	$ 429.8

Debt and Credit Facilities - Ad

Debt and Credit Facilities - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Credit Facility, Potential Increase Amount	$ 150,000,000
Credit Facility, Potential Maximum Borrowing Capacity	$ 400,000,000
Standby Letters of Credit
Debt Instrument [Line Items]
Change of control threshold	50.00%
Revolving Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 250,000,000
Revolving Credit Agreement | Standby Letters of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity	100,000,000
Credit facility, standby letters of credit	3,900,000	$ 3,900,000
Receivables Purchase Agreement
Debt Instrument [Line Items]
Outstanding borrowings under revolving credit agreement	0	0
Secured accounts receivable facility	200,000,000
Secured Credit Facility | Standby Letters of Credit
Debt Instrument [Line Items]
Credit facility, standby letters of credit	$ 65,300,000	$ 63,800,000
Minimum | Unsecured Senior Notes | Senior Notes
Debt Instrument [Line Items]
Debt prepayment terms, period from date of prepayment notice	20 days
Maximum | Unsecured Senior Notes | Senior Notes
Debt Instrument [Line Items]
Debt prepayment terms, period from date of prepayment notice	60 days

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Leased Assets [Line Items]
Lease expense	$ 37	$ 38	$ 45.6

Leases - Schedule of Operating

Leases - Schedule of Operating and Capital Lease Future Payments (Details) $ in Millions	Dec. 31, 2018USD ($)
Operating Leases
2,019	$ 35.8
2,020	25.7
2,021	14.9
2,022	8.4
2,023	6.8
2024 and thereafter	12.7
Total	104.3
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,019	6.9
2,020	0.2
2,021	0
2,022	0
2,023	0
2024 and thereafter	0
Total	7.1
Amount representing interest	(0.2)
Present value of minimum lease payments	6.9
Current maturities	(6.7)
Long-term capital lease obligations	$ 0.2

Leases - Schedule of Capital Le

Leases - Schedule of Capital Leased Assets (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Capital Leased Assets [Line Items]
Accumulated amortization	$ (11.2)	$ (12.6)
Total	10.1	13.8
Transportation equipment
Capital Leased Assets [Line Items]
Capital leased assets, gross	19.9	25
Real property
Capital Leased Assets [Line Items]
Capital leased assets, gross	0.8	0.8
Other property
Capital Leased Assets [Line Items]
Capital leased assets, gross	$ 0.6	$ 0.6

Leases - Summary of Investment

Leases - Summary of Investment in Lease Receivables (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Operating Leased Assets [Line Items]
Future minimum payments to be received on leases	$ 140	$ 141.2
Guaranteed residual lease values	151	130.7
Total minimum lease payments to be received	291	271.9
Unearned income	(28.7)	(28.1)
Net investment in leases	262.3	243.8
Current maturities of lease receivables	129.6	106.6
Less—allowance for doubtful accounts	(0.5)	(1.7)
Current portion of lease receivables—net of allowance	129.1	104.9
Lease receivables—noncurrent	$ 133.2	$ 138.9
Minimum
Operating Leased Assets [Line Items]
Terms of direct financing lease (in years)	1 year
Maximum
Operating Leased Assets [Line Items]
Terms of direct financing lease (in years)	5 years

Leases - Summary of Principal A

Leases - Summary of Principal Amounts to be Received on Lease Receivables (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Leases [Abstract]
2,019	$ 149
2,020	112.7
2,021	29
2,022	0.3
2,023	0
2024 and thereafter	0
Total minimum lease payments to be received	291	$ 271.9
Lease payments greater than 90 days past due	$ 0.3

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Corporate income tax rate	21.00%	35.00%	35.00%
Accrued interest and penalties on unrecognized tax benefits	$ 1.4	$ 1.2
Net operating loss carryforwards	224.7
Tax credit carryforwards	0.4
Deferred tax assets, operating loss carryforwards	17.9
Deferred tax asset, tax credit carryforwards	0.3
Deferred tax assets, valuation allowance	5.8	$ 4.4
Operating loss carryforwards, valuation allowance	5.5
Tax credit carryforwards, valuation allowance	$ 0.3

Income Taxes - Components of th

Income Taxes - Components of the Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal	$ 21.7	$ 19.3	$ 24.4
State and other	11.8	5.6	7.5
Current income tax provision	33.5	24.9	31.9
Deferred:
Federal	54.2	71.4	71.2
State and other	6.7	6.7	5.6
Impact of the Tax Cuts and Jobs Act	1.3	(229.5)	0
Deferred income tax provision	62.2	(151.4)	76.8
Total provision for (benefit from) income taxes	$ 95.7	$ (126.5)	$ 108.7

Income Taxes - Effective Tax Ra

Income Taxes - Effective Tax Rate Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income tax at federal statutory rate	$ 76.6	$ 92.2	$ 93
Corporate income tax rate	21.00%	35.00%	35.00%
State tax, net of federal effect	$ 15.4	$ 8.6	$ 10.5
State tax, net of federal effect, rate	4.20%	3.30%	3.90%
Nondeductible meals and entertainment	$ 2.1	$ 3.4	$ 3.4
Nondeductible meals and entertainment, rate	0.60%	1.30%	1.30%
Impact of the Tax Cuts and Jobs Act	$ 1.3	$ (229.5)	$ 0
Impact of the Tax Cuts and Jobs Act, rate	0.30%	(87.10%)	0.00%
Other, net	$ 0.3	$ (1.2)	$ 1.8
Other, net, rate	0.10%	(0.50%)	0.70%
Total provision for (benefit from) income taxes	$ 95.7	$ (126.5)	$ 108.7
Total provision for income taxes, rate	26.20%	(48.00%)	40.90%

Income Taxes - Summary of Defer

Income Taxes - Summary of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Allowances for doubtful accounts	$ 1.1	$ 1.1
Compensation and employee benefits	14.7	15.6
Insurance and claims accruals	2.6	2.8
State net operating losses and credit carryforwards	18.2	17.7
Other	5	4
Total gross deferred tax assets	41.6	41.2
Valuation allowance	(5.8)	(4.4)
Total deferred tax assets, net of valuation allowance	35.8	36.8
Deferred tax liabilities:
Property and equipment	466.5	410.8
Prepaid expenses	4.3	3.6
Intangibles	11.1	8.7
Other	4.5	0.3
Total gross deferred tax liabilities	486.4	423.4
Net deferred tax liability	$ 450.6	$ 386.6

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Gross unrecognized tax benefits - beginning of year	$ 2.8	$ 2.4	$ 2
Gross increases - tax positions related to current year	0.8	0.4	0.5
Gross decreases - tax positions taken in prior years	0	0	(0.1)
Lapse of statutes	(0.3)	0	0
Gross unrecognized tax benefits - end of year	$ 3.3	$ 2.8	$ 2.4

Temporary Equity - Rollfoward (

Temporary Equity - Rollfoward (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	9 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Increase (Decrease) in Temporary Equity
Beginning balance, value		$ 0	$ 1,186.4
Net income			22.6
Other comprehensive income			0
Dividends declared at $0.05 per share			(7.8)
Transfer from temporary equity to common equity, value			(1,201.2)
Ending balance, value	$ 0		$ 0	$ 1,186.4
Dividends declared per share (usd per share)	$ 0.15	$ 0.24	$ 0.2	$ 0.2
Accumulated Earnings
Increase (Decrease) in Temporary Equity
Beginning balance, value		$ 0	$ 125.1
Net income			22.6
Dividends declared at $0.05 per share			(7.8)
Change in redemption value of redeemable common shares			(126.6)
Transfer from temporary equity to common equity, value			(13.3)
Ending balance, value	$ 0		0	$ 125.1
Accumulated Other Comprehensive Income
Increase (Decrease) in Temporary Equity
Beginning balance, value		0	0.9
Other comprehensive income			0
Transfer from temporary equity to common equity, value			(0.9)
Ending balance, value	0		0	0.9
Class A Redeemable Common Shares
Increase (Decrease) in Temporary Equity
Beginning balance, value		$ 0	$ 563.2
Beginning balance, shares		0	83
Change in redemption value of redeemable common shares			$ 67.3
Transfer from temporary equity to common equity, value			$ (630.5)
Transfer from temporary equity to common equity, shares			(83)
Ending balance, value	$ 0		$ 0	$ 563.2
Ending balance, shares	0		0	83
Class B Redeemable Common Shares
Increase (Decrease) in Temporary Equity
Beginning balance, value		$ 0	$ 497.2
Beginning balance, shares		0	73.3
Change in redemption value of redeemable common shares			$ 59.3
Transfer from temporary equity to common equity, value			$ (556.5)
Transfer from temporary equity to common equity, shares			(73.3)
Ending balance, value	$ 0		$ 0	$ 497.2
Ending balance, shares	0		0	73.3
Temporary Equity
Increase (Decrease) in Temporary Equity
Dividends declared per share (usd per share)		$ 0.05

Common Equity - Calculation of

Common Equity - Calculation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Basic earnings per common share
Net income available to common shareholders	$ 84.8	$ 70.7	$ 65.8	$ 47.6	$ 283.9	$ 36.9	$ 46.5	$ 22.6	$ 367.4	$ 268.9	$ 389.9	$ 156.9
Weighted average common shares issued and outstanding										177	171.1	156.6
Diluted earnings per common share
Effect of dilutive restricted share units										0.2	0.2	0.2
Weighted average diluted common shares issued and outstanding										177.2	171.3	156.8
Basic earnings per common share	$ 0.48	$ 0.40	$ 0.37	$ 0.27	$ 1.60	$ 0.21	$ 0.27	$ 0.14		$ 1.52	$ 2.28	$ 1
Diluted earnings per common share	$ 0.48	$ 0.40	$ 0.37	$ 0.27	$ 1.60	$ 0.21	$ 0.27	$ 0.14		$ 1.52	$ 2.28	$ 1

Common Equity - Additional Info

Common Equity - Additional Information (Details)	Mar. 21, 2017shares	Jan. 31, 2019$ / shares	Dec. 31, 2017$ / shares	Dec. 31, 2018$ / shares	Dec. 31, 2017$ / shares	Dec. 31, 2016$ / shares
Class of Stock [Line Items]
Shares issued, stock split | shares	29
Stockholders' equity, stock split, conversion ratio	30
Dividends declared per share (usd per share)			$ 0.15	$ 0.24	$ 0.2	$ 0.2
Subsequent Event | Class A Common Shares
Class of Stock [Line Items]
Dividends declared per share (usd per share)		$ 0.06

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Contribution Plan
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, expense	$ 12	$ 11.2	$ 10.7
401K Plan
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan, expense	$ 12.1	$ 10.7	$ 10

Share-based Compensation - Addi

Share-based Compensation - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to outstanding share-based compensation awards	$ 11.6
Unrecognized compensation cost related to outstanding share-based compensation awards, recognition period	2 years 6 months
Expense associated with director equity award	$ 10.9	$ 5.2	$ 2.2
Restricted Shares and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Expense associated with director equity award	$ 3.1	1.5	0
Pre-IPO Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Expense associated with director equity award	$ 0.9	1.9	$ 2.2
Pre-IPO Plan | Restricted Shares and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense associated with director equity award	$ 1.4	$ 1.4

Share-based Compensation - Comp

Share-based Compensation - Components of Share-Based Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 10.9	$ 5.2	$ 2.2
Related tax benefit	2.8	2	0.9
Restricted Shares and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	3.1	1.5	0
Pre-IPO Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	0.9	1.9	2.2
Performance Shares and PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	5.5	1.2	0
Nonqualified Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 1.4	$ 0.6	$ 0

Share-based Compensation - Rest

Share-based Compensation - Restricted Shares and RSUs (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restricted Shares and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Number of Awards
Unvested, Beginning Balance (in shares)	240,016	0
Granted (in shares)	229,272	246,516
Vested (in shares)	(74,828)	0
Forfeited (in shares)	(24,983)	(6,500)
Unvested, Ending Balance (in shares)	369,477	240,016	0
Weighted Average Grant Date Fair Value
Unvested, Beginning Balance (usd per share)	$ 19	$ 0
Granted (usd per share)	26.82	19
Vested (usd per share)	19	0
Forfeited (usd per share)	21.26	19
Unvested, Ending Balance (usd per share)	$ 23.70	$ 19	$ 0
Pre-IPO Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Number of Awards
Unvested, Beginning Balance (in shares)	152,199	777,210	798,960
Granted (in shares)	0	0	386,370
Vested (in shares)	(101,643)	(621,722)	(398,220)
Forfeited (in shares)	(6,225)	(3,289)	(9,900)
Unvested, Ending Balance (in shares)	44,331	152,199	777,210
Weighted Average Grant Date Fair Value
Unvested, Beginning Balance (usd per share)	$ 19	$ 6.31	$ 5.63
Granted (usd per share)	0	0	6.78
Vested (usd per share)	19	7.59	5.42
Forfeited (usd per share)	19	19	6.17
Unvested, Ending Balance (usd per share)	$ 19	$ 19	$ 6.31
First period | Restricted Shares and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	25.00%
Second Period | Restricted Shares and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	25.00%
Third Period | Restricted Shares and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	25.00%
Fourth Period | Restricted Shares and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	25.00%
One-time 2018 Grant | First period | Restricted Shares and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	5 years
Vesting percentage	50.00%
One-time 2018 Grant | Second Period | Restricted Shares and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	6 years
Vesting percentage	50.00%

Share-based Compensation - Perf

Share-based Compensation - Performance Shares and PSUs (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pre-IPO Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre-IPO share grant vesting period	3 years
Number of Awards
Unvested, Beginning Balance (in shares)	152,199	777,210	798,960
Granted (in shares)	0	0	386,370
Vested (in shares)	(101,643)	(621,722)	(398,220)
Forfeited (in shares)	(6,225)	(3,289)	(9,900)
Unvested, Ending Balance (in shares)	44,331	152,199	777,210
Weighted Average Grant Date Fair Value
Unvested, Beginning Balance (usd per share)	$ 19	$ 6.31	$ 5.63
Granted (usd per share)	0	0	6.78
Vested (usd per share)	19	7.59	5.42
Forfeited (usd per share)	19	19	6.17
Unvested, Ending Balance (usd per share)	$ 19	$ 19	$ 6.31
Performance Shares and PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period	3 years
Number of Awards
Unvested, Beginning Balance (in shares)	391,541	0
Granted (in shares)	303,228	396,201
Vested (in shares)	0	0
Forfeited (in shares)	(56,390)	(4,660)
Unvested, Ending Balance (in shares)	638,379	391,541	0
Weighted Average Grant Date Fair Value
Unvested, Beginning Balance (usd per share)	$ 19	$ 0
Granted (usd per share)	26.78	19
Vested (usd per share)	0	0
Forfeited (usd per share)	19.65	19
Unvested, Ending Balance (usd per share)	$ 22.64	$ 19	$ 0
Minimum | PSU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout range	0.00%
Minimum | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout range	0.00%
Maximum | PSU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout range	200.00%
Maximum | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout range	100.00%

Share-based Compensation - Nonq

Share-based Compensation - Nonqualified Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 29, 2017
Number of Awards
Unvested, Beginning Balance (in shares)	229,620	0
Granted (in shares)	173,024	229,620
Vested (in shares)	(57,405)	0
Forfeited (in shares)	(25,230)	0
Unvested, Ending Balance (in shares)	320,009	229,620
Weighted Average Exercise Price
Weighted Average Grant Date Fair Value, Beginning Balance	$ 6.37	$ 0
Granted (usd per share)	8.96	6.37
Vested (usd per share)	6.37	0
Forfeited (usd per share)	6.37	0
Weighted Average Grant Date Fair Value, Beginning Balance	$ 7.77	$ 6.37
Non-Qualified Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Expiration period	10 years
Number of Awards
Unvested, Beginning Balance (in shares)	229,620	0
Granted (in shares)	173,024	229,620
Vested (in shares)	(8,410)	0
Forfeited (in shares)	(25,230)	0
Unvested, Ending Balance (in shares)	369,004	229,620
Exercise date, number of awards (in shares)	48,995	0
Exercise date, weighted average exercise price (in dollars per share)	$ 19	$ 0
Exercise date, weighted average remaining contractual term (in years)	8 years 3 months 18 days	0 days
Exercise date, aggregate intrinsic value	$ 0	$ 0
Weighted Average Exercise Price
Weighted Average Exercise Price, Beginning Balance	$ 19	$ 0
Granted (usd per share)	26.74	19
Vested (usd per share)	19	0
Forfeited (usd per share)	19	0
Weighted Average Exercise Price, Ending Balance	$ 22.63	$ 19
Weighted Average Remaining Contractual Term	8 years 8 months 12 days	9 years 3 months 18 days
Aggregate Intrinsic Value	$ 0	$ 2,195,000
Aggregate intrinsic value, exercised	$ 67
Share Price	$ 18.67		$ 28.56
Proceeds from Stock Options Exercised	$ 200	$ 0
First period | Non-Qualified Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
Vesting percentage	25.00%

Share-based Compensation - Stoc

Share-based Compensation - Stock Option Assumptions (Details) - Nonqualified Stock Options - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average Black-Scholes value (usd per share)	$ 8.96	$ 6.37
Black-Scholes Assumptions:
Expected term	6 years 3 months	6 years 3 months
Expected volatility	32.20%	35.00%
Expected dividend yield	0.90%	1.10%
Risk-free interest rate	2.80%	2.20%

Other Long-Term Incentive Com_2

Other Long-Term Incentive Compensation (Details) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)performance_metricshares	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 10.9	$ 5.2	$ 2.2
Legacy Long-term Cash Incentive Compensation Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 11.2	10.8	$ 13.7
Stock Appreciation Rights (SARs) | 2011 Omnibus Long-term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive plan, vesting period	3 years
Incentive plan, payment period subsequent to performance period	90 days
Incentive plan, award vesting rights, percentage	100.00%
Awards outstanding (in shares) | shares	2.5
Incentive plan, liability on share-based awards	$ 9	8.4
Cash Awards | 2011 Omnibus Long-term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive plan, number of performance metrics | performance_metric	2
Incentive plan, performance period	5 years
Incentive plan, vesting period	3 years
Incentive plan, payment period subsequent to performance period	90 days
Incentive plan, liability on cash awards	$ 22.7	25.6
Cash Awards | 2011 Omnibus Long-term Incentive Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive plan, target percentage of awards	0.00%
Cash Awards | 2011 Omnibus Long-term Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive plan, target percentage of awards	250.00%
Cash Awards | 2005 Schneider National, Inc. Long-Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive plan, vesting period	5 years
Incentive plan, liability on cash awards	$ 8.6	$ 8.8
Incentive plan, award vesting rights, percentage	20.00%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) $ in Millions	Dec. 31, 2018USD ($)
Commitments and Contingencies Disclosure [Abstract]
Commitments to purchase transportation equipment	$ 265.5

Segment Reporting - Additional

Segment Reporting - Additional Information (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2018USD ($)Segment	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment									3
Operating revenues	$ 1,321.6	$ 1,280.1	$ 1,236.3	$ 1,139	$ 1,191.2	$ 1,110.8	$ 1,075.2	$ 1,006.4	$ 4,977	$ 4,383.6	$ 4,045.7
Other
Segment Reporting Information [Line Items]
Operating revenues									322	293.6	240.5
Other | Other Insurance
Segment Reporting Information [Line Items]
Operating revenues									$ 82.7	$ 78.4	$ 54.4
Logistics
Segment Reporting Information [Line Items]
Number of operating segments | Segment									3

Segment Reporting - Revenue by

Segment Reporting - Revenue by Segment (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Operating revenues	$ 1,321.6	$ 1,280.1	$ 1,236.3	$ 1,139	$ 1,191.2	$ 1,110.8	$ 1,075.2	$ 1,006.4	$ 4,977	$ 4,383.6	$ 4,045.7
Reportable segments | Truckload
Segment Reporting Information [Line Items]
Operating revenues									2,268	2,187.4	2,091
Reportable segments | Intermodal
Segment Reporting Information [Line Items]
Operating revenues									953.5	779.9	757.5
Reportable segments | Logistics
Segment Reporting Information [Line Items]
Operating revenues									1,024.6	834.3	737.7
Other
Segment Reporting Information [Line Items]
Operating revenues									322	293.6	240.5
Fuel surcharge
Segment Reporting Information [Line Items]
Operating revenues									522.8	386.3	294
Intersegment Eliminations
Segment Reporting Information [Line Items]
Operating revenues									$ (113.9)	$ (97.9)	$ (75)

Segment Reporting - Income From

Segment Reporting - Income From Operations (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Income from operations	$ 118.6	$ 97.9	$ 91.7	$ 67.6	$ 93.7	$ 64.1	$ 79	$ 43.5	$ 375.8	$ 280.3	$ 290.4
Reportable segments | Truckload
Segment Reporting Information [Line Items]
Income from operations									240.5	196.2	221.1
Reportable segments | Intermodal
Segment Reporting Information [Line Items]
Income from operations									130.2	52.3	46.1
Reportable segments | Logistics
Segment Reporting Information [Line Items]
Income from operations									47.4	34.2	30.7
Other
Segment Reporting Information [Line Items]
Income from operations									$ (42.3)	$ (2.4)	$ (7.5)

Segment Reporting - Depreciatio

Segment Reporting - Depreciation and Amortization Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Depreciation and amortization expense	$ 291.3	$ 279	$ 266
Reportable segments | Truckload
Segment Reporting Information [Line Items]
Depreciation and amortization expense	211	205.9	192.6
Reportable segments | Intermodal
Segment Reporting Information [Line Items]
Depreciation and amortization expense	39.8	34.5	30.9
Reportable segments | Logistics
Segment Reporting Information [Line Items]
Depreciation and amortization expense	0.4	0.4	0.4
Other
Segment Reporting Information [Line Items]
Depreciation and amortization expense	$ 40.1	$ 38.2	$ 42.1

Quarterly Results of Operatio_3

Quarterly Results of Operations (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Operating revenues	$ 1,321.6	$ 1,280.1	$ 1,236.3	$ 1,139	$ 1,191.2	$ 1,110.8	$ 1,075.2	$ 1,006.4		$ 4,977	$ 4,383.6	$ 4,045.7
Income from operations	118.6	97.9	91.7	67.6	93.7	64.1	79	43.5		375.8	280.3	290.4
Net income	$ 84.8	$ 70.7	$ 65.8	$ 47.6	$ 283.9	$ 36.9	$ 46.5	$ 22.6	$ 367.4	$ 268.9	$ 389.9	$ 156.9
Basic earnings per common share	$ 0.48	$ 0.40	$ 0.37	$ 0.27	$ 1.60	$ 0.21	$ 0.27	$ 0.14		$ 1.52	$ 2.28	$ 1
Diluted earnings per common share	$ 0.48	$ 0.40	$ 0.37	$ 0.27	$ 1.60	$ 0.21	$ 0.27	$ 0.14		$ 1.52	$ 2.28	$ 1

Schedule II - Valuation and Q_2

Schedule II - Valuation and Qualifying Accounts (Details) - Allowance for Doubtful Accounts - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 5.2	$ 3.5	$ 3.6
Charged to Expense / Against Revenue	3.7	3.7	(0.3)
Write-offs, Net of Recoveries	(2.1)	(2)	0.2
Balance at End of Year	$ 6.8	$ 5.2	$ 3.5

Uncategorized Items - sndr-2018

Label	Element	Value
Dividends	us-gaap_Dividends	$ 26,500,000
Stock Issued During Period, Value, Other	us-gaap_StockIssuedDuringPeriodValueOther	2,900,000
Stock Repurchased and Retired During Period, Value	us-gaap_StockRepurchasedAndRetiredDuringPeriodValue	100,000
Stock Issued During Period, Value, Issued for Services	us-gaap_StockIssuedDuringPeriodValueIssuedForServices	800,000
Additional Paid-in Capital [Member]
Stock Issued During Period, Value, Other	us-gaap_StockIssuedDuringPeriodValueOther	2,900,000
Stock Repurchased and Retired During Period, Value	us-gaap_StockRepurchasedAndRetiredDuringPeriodValue	100,000
Stock Issued During Period, Value, Issued for Services	us-gaap_StockIssuedDuringPeriodValueIssuedForServices	800,000
Retained Earnings [Member]
Dividends	us-gaap_Dividends	26,500,000
Net Income (Loss) Attributable to Parent	us-gaap_NetIncomeLoss	$ 367,400,000