Significant Accounting Policies (Policies)	6 Months Ended
Jun. 30, 2020
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation The accompanying unaudited interim Condensed Consolidated Financial Statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information. We believe such statements include all adjustments (consisting only of normal recurring adjustments) necessary for the fair presentation of our financial position, results of operations and cash flows at the dates and for the periods indicated. Pursuant to the requirements of the Securities and Exchange Commission (SEC) applicable to quarterly reports on Form 10-Q, the accompanying financial statements do not include all disclosures required by GAAP for annual financial statements. While we believe the disclosures presented are adequate to make the information not misleading, these unaudited interim Condensed Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and related notes included in our Annual Report on Form 10-K for the year ended December 31, 2019. Operating results for the periods presented in this report are not necessarily indicative of the results that may be expected for the calendar year ending December 31, 2020, or any other interim period. Our business is somewhat seasonal with slightly higher freight volumes typically experienced during August through early November in our full-load freight transportation business.
Use of Estimates, Policy [Policy Text Block]	Use of Estimates The novel coronavirus (COVID-19) pandemic has created and may continue to create significant uncertainty in macro-economic conditions, which may cause global economic recession, business slowdowns or shutdowns, depressed demand for our transportation and logistics businesses, and adversely impact our results of operations. During the six months ended June 30, 2020, we faced increasing uncertainties around our estimates on our accounts receivable credit losses and goodwill and intangibles assets. We expect uncertainties around our key accounting estimates to continue to evolve depending on the duration and degree of impact associated with the COVID-19 pandemic. Our estimates may change, as new events occur and additional information is obtained, which are recognized or disclosed in our consolidated financial statements as soon as they become known and may have a material impact on our financial statements.
New Accounting Pronouncements, Policy [Policy Text Block]	Accounting Pronouncement Adopted in 2020 In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2016-13, Financial Instruments – Credit Losses, which replaced the existing incurred loss methodology used for establishing a provision against financial assets, including accounts receivable, with a forward-looking expected loss methodology for accounts receivable, loans and other financial instruments. We adopted the new standard on January 1, 2020, using the cumulative-effect method. The adoption of the new guidance did not have a material impact on our financial statements.
Receivable [Policy Text Block]	Accounts Receivable and Allowance Our trade accounts receivable includes accounts receivable reduced by an allowance for uncollectible accounts. Receivables are recorded at amounts billed to customers when loads are delivered or services are performed. The allowance for uncollectible accounts is calculated over the life of the underlying receivable and is based on historical experience; any known trends or uncertainties related to customer billing and account collectability; current economic conditions; and reasonable and supportable economic forecasts, each applied to segregated risk pools based on the business segment that generated the receivable. The adequacy of our allowance is reviewed quarterly. Balances are charged against the allowance when it is determined the receivable will not be recovered. The allowance for uncollectible accounts for our trade accounts receivable was $18.0 million at June 30, 2020 and $13.3 million at December 31, 2019. During the three and six months ended June 30, 2020, the allowance for uncollectible accounts increased by $4.7 million and $6.2 million, respectively, and was reduced $1.1 million and $1.5 million, respectively, by write-offs during the same periods.

Use of Estimates, Policy [Policy Text Block]

Use of Estimates

The novel coronavirus (COVID-19) pandemic has created and may continue to create significant uncertainty in macro-economic conditions, which may cause global economic recession, business slowdowns or shutdowns, depressed demand for our transportation and logistics businesses, and adversely impact our results of operations. During the six months ended June 30, 2020, we faced increasing uncertainties around our estimates on our accounts receivable credit losses and goodwill and intangibles assets. We expect uncertainties around our key accounting estimates to continue to evolve depending on the duration and degree of impact associated with the COVID-19 pandemic. Our estimates may change, as new events occur and additional information is obtained, which are recognized or disclosed in our consolidated financial statements as soon as they become known and may have a material impact on our financial statements.

Receivable [Policy Text Block]

Accounts Receivable and Allowance

Our trade accounts receivable includes accounts receivable reduced by an allowance for uncollectible accounts. Receivables are recorded at amounts billed to customers when loads are delivered or services are performed. The allowance for uncollectible accounts is calculated over the life of the underlying receivable and is based on historical experience; any known trends or uncertainties related to customer billing and account collectability; current economic conditions; and reasonable and supportable economic forecasts, each applied to segregated risk pools based on the business segment that generated the receivable. The adequacy of our allowance is reviewed quarterly. Balances are charged against the allowance when it is determined the receivable will not be recovered. The allowance for uncollectible accounts for our trade accounts receivable was $18.0 million at June 30, 2020 and $13.3 million at December 31, 2019. During the three and six months ended June 30, 2020, the allowance for uncollectible accounts increased by $4.7 million and $6.2 million, respectively, and was reduced $1.1 million and $1.5 million, respectively, by write-offs during the same periods.