Basis of Presentation Basis of Presentation (Policies)	3 Months Ended
Mar. 31, 2026
Basis of Presentation [Abstract]
Basis of Presentation [Policy Text Block]	Basis of Presentation and New Accounting Pronouncements Heartland Express, Inc. is a holding company incorporated in Nevada, which directly or indirectly owns all of the stock of the following legal entities: Heartland Express, Inc. of Iowa, Heartland Express Services, Inc., Heartland Express Maintenance Services, Inc. (collectively, "Heartland Express"), and Midwest Holding Group, LLC and Millis Transfer, LLC (together, "Millis Transfer"), and Smith Transport, LLC ("Smith Transport"), and certain Mexican entities. Effective December 31, 2025, we integrated and rebranded U.S. operations of Contract Freighters, Inc. ("CFI") into Heartland Express. We, together with our subsidiaries, are a short, medium, and long-haul truckload carrier and transportation services provider. The accompanying consolidated financial statements include the parent company, Heartland Express, Inc., and its subsidiaries, all of which are wholly owned. All material intercompany items and transactions have been eliminated in consolidation. The accompanying unaudited consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP") for interim financial information and with the instructions to Form 10-Q and Regulation S-X. Accordingly, they do not include all of the information and notes to the financial statements required by U.S. GAAP for complete financial statements. In the opinion of management, all normal, recurring adjustments considered necessary for a fair presentation have been included. The consolidated financial statements should be read in conjunction with the audited consolidated financial statements and accompanying notes for the year ended December 31, 2025 included in the Annual Report on Form 10-K the Company filed with the Securities and Exchange Commission (the "SEC") on March 3, 2026. Interim results of operations are not necessarily indicative of the results to be expected for the full year or any other interim periods.
Use of Estimates, Policy [Policy Text Block]	Use of EstimatesThe preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Segment Reporting, Policy [Policy Text Block]	Segment Information We primarily provide nationwide asset-based dry van truckload service for major shippers across the United States, along with cross-border freight and other transportation services offered through third party partnerships in Mexico. We also offer truckload temperature-controlled transportation services and Mexico logistics services, which are not significant to our operations. Our Chief Operating Decision Maker (“CODM”) oversees and manages all of our transportation services, on a combined basis, including previously acquired entities. In addition to consolidated data on a combined basis that has been historically used, our CODM also makes use of available disaggregated operating segment data as well. However, those operating segments share similar economic characteristics and meet operating segment aggregation criteria. As a result of the foregoing, we have determined that we have one reportable segment, consistent with the authoritative accounting guidance on disclosures about segments of an enterprise and related information. The accounting policies for the reportable segment are the same as those for the Company. The CODM is our CEO and President. The primary measure of profit or loss utilized by our CODM is operating ratio (operating expenses as a percentage of operating revenues) which is regularly reviewed to allocate resources and assess performance of our reportable segment. In addition to operating ratio, our CODM also regularly reviews consolidated net income to allocate resources and assess performance of our reportable segment when we have significant non-operating activity as is the case currently given we have significant interest expense as a result of debt resulting from an acquisition. The revenue, costs and expenses for the reportable segment are the same as those presented on the Consolidated Statements of Comprehensive Income as there are no other significant segment expenses that would require disclosure or other segment items needed to reconcile to the Consolidated Statements of Comprehensive Income. There are no other segment items as there are no significant assets or operations not regularly reviewed by the CODM.
Revenue [Policy Text Block]	The Company recognizes revenue over time as control of the promised services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those services. The delivery of the shipment and completion of the performance obligation allows for the collection of payment predominantly within 30 days after the delivery date of the shipment for the majority of our customers. The Company's operations are consistent with those in the trucking industry where freight is hauled twenty-four hours a day and seven days a week, subject to hours of service rules. Approximately 80% of our loads are less than 500 miles in length of haul. Each individual shipment accepted by the Company is considered a separate contract with the performance obligation being the delivery of the freight. Our average length of haul for each load of freight generally equals less than two days of continuous transit time. The Company has therefore applied the practical expedient and has not disclosed the amount of remaining unsatisfied performance obligations. The Company estimates revenue for multiple-stop loads based on miles run and estimates revenue for single stop loads based on transit time, as the customer simultaneously receives and consumes the benefit provided. The Company hauls freight and earns revenue on a consistent basis throughout the periods presented.
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and Cash EquivalentsCash equivalents are short-term, highly liquid investments with insignificant interest rate risk and original maturities of three months or less at acquisition.
Property, Plant, and Equipment [Policy Text Block]	Prepaid Tires, Property, Equipment, and Depreciation Property and equipment are reported at cost, net of accumulated depreciation. Maintenance and repairs are charged to operations as incurred. New tires are capitalized separately from revenue equipment and are reported separately as “Prepaid tires” in the consolidated balance sheets and amortized over two years. Depreciation for financial statement purposes is computed by the straight-line method for all assets other than new tractors. We recognize depreciation expense on new tractors (excludes tractors acquired through an acquisition) using the declining balance method. Revenue equipment acquired through acquisitions is generally revalued to current market values as of the acquisition date. Assets obtained more than a year prior to the acquisition by the acquired company are depreciated on a straight-line basis aligned with the remaining period of expected use, whereas those obtained less than a year prior are depreciated consistent with newly purchased assets. As acquired equipment is replaced, our fleet returns to our base methods of declining balance depreciation for tractors and straight-line depreciation for trailers. New tractors are depreciated to salvage values of $15,000 while new trailers are depreciated to salvage values of $4,000. Revenue equipment acquired through acquisitions is generally revalued to current market values as of the acquisition date. At March 31, 2026, there were $2.6 million receivables related to equipment sales recorded in other current assets compared to $0.5 million at December 31, 2025.
Earnings Per Share, Policy [Policy Text Block]	Earnings per ShareBasic (loss) earnings per share is based upon the weighted average common shares outstanding during each year. Diluted (loss) earnings per share is based on the basic weighted (loss) earnings per share with additional weighted common shares for common stock equivalents.
Income Tax, Policy [Policy Text Block]	We use the asset and liability method of accounting for income taxes. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statement carrying amount of existing assets and liabilities and their respective tax basis. 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. Such amounts are adjusted, as appropriate, to reflect changes in tax rates expected to be in effect when temporary differences reverse. The effect of a change in tax rates on deferred taxes is recognized in the period that the change is enacted. A valuation allowance is recorded to reduce the Company's deferred tax assets to the amount that is more likely than not to be realized.
Income Tax Uncertainties, Policy [Policy Text Block]	We recognize the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that is greater than 50% likely of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. We record interest and penalties related to unrecognized tax benefits in income tax expense.

Basis of Presentation Basis of Presentation (Policies)

3 Months Ended

Mar. 31, 2026

Basis of Presentation [Policy Text Block]

Basis of Presentation and New Accounting Pronouncements

Heartland Express, Inc. is a holding company incorporated in Nevada, which directly or indirectly owns all of the stock of the following legal entities: Heartland Express, Inc. of Iowa, Heartland Express Services, Inc., Heartland Express Maintenance Services, Inc. (collectively, "Heartland Express"), and Midwest Holding Group, LLC and Millis Transfer, LLC (together, "Millis Transfer"), and Smith Transport, LLC ("Smith Transport"), and certain Mexican entities. Effective December 31, 2025, we integrated and rebranded U.S. operations of Contract Freighters, Inc. ("CFI") into Heartland Express. We, together with our subsidiaries, are a short, medium, and long-haul truckload carrier and transportation services provider.

The accompanying consolidated financial statements include the parent company, Heartland Express, Inc., and its subsidiaries, all of which are wholly owned. All material intercompany items and transactions have been eliminated in consolidation. The accompanying unaudited consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP") for interim financial information and with the instructions to Form 10-Q and Regulation S-X. Accordingly, they do not include all of the information and notes to the financial statements required by U.S. GAAP for complete financial statements. In the opinion of management, all normal, recurring adjustments considered necessary for a fair presentation have been included. The consolidated financial statements should be read in conjunction with the audited consolidated financial statements and accompanying notes for the year ended December 31, 2025 included in the Annual Report on Form 10-K the Company filed with the Securities and Exchange Commission (the "SEC") on March 3, 2026. Interim results of operations are not necessarily indicative of the results to be expected for the full year or any other interim periods.

Use of Estimates, Policy [Policy Text Block]

Use of EstimatesThe preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

Segment Reporting, Policy [Policy Text Block]

Segment Information

We primarily provide nationwide asset-based dry van truckload service for major shippers across the United States, along with cross-border freight and other transportation services offered through third party partnerships in Mexico. We also offer truckload temperature-controlled transportation services and Mexico logistics services, which are not significant to our operations. Our Chief Operating Decision Maker (“CODM”) oversees and manages all of our transportation services, on a combined basis, including previously acquired entities. In addition to consolidated data on a combined basis that has been historically used, our CODM also makes use of available disaggregated operating segment data as well. However, those operating segments share similar economic characteristics and meet operating segment aggregation criteria. As a result of the foregoing, we have determined that we have one reportable segment, consistent with the authoritative accounting guidance on disclosures about segments of an enterprise and related information.

The accounting policies for the reportable segment are the same as those for the Company. The CODM is our CEO and President. The primary measure of profit or loss utilized by our CODM is operating ratio (operating expenses as a percentage of operating revenues) which is regularly reviewed to allocate resources and assess performance of our reportable segment. In addition to operating ratio, our CODM also regularly reviews consolidated net income to allocate resources and assess performance of our reportable segment when we have significant non-operating activity as is the case currently given we have significant interest expense as a result of debt resulting from an acquisition. The revenue, costs and expenses for the reportable segment are the same as those presented on the Consolidated Statements of Comprehensive Income as there are no other significant segment expenses that would require disclosure or other segment items needed to reconcile to the Consolidated Statements of Comprehensive Income. There are no other segment items as there are no significant assets or operations not regularly reviewed by the CODM.

Revenue [Policy Text Block]

The Company recognizes revenue over time as control of the promised services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those services. The delivery of the shipment and completion of the performance obligation allows for the collection of payment predominantly within 30 days after the delivery date of the shipment for the majority of our customers.

The Company's operations are consistent with those in the trucking industry where freight is hauled twenty-four hours a day and seven days a week, subject to hours of service rules. Approximately 80% of our loads are less than 500 miles in length of haul. Each individual shipment accepted by the Company is considered a separate contract with the performance obligation being the delivery of the freight. Our average length of haul for each load of freight generally equals less than two days of continuous transit time. The Company has therefore applied the practical expedient and has not disclosed the amount of remaining unsatisfied performance obligations. The Company estimates revenue for multiple-stop loads based on miles run and estimates revenue for single stop loads based on transit time, as the customer simultaneously receives and consumes the benefit provided. The Company hauls freight and earns revenue on a consistent basis throughout the periods presented.

Cash and Cash Equivalents, Policy [Policy Text Block]

Cash and Cash EquivalentsCash equivalents are short-term, highly liquid investments with insignificant interest rate risk and original maturities of three months or less at acquisition.

Property, Plant, and Equipment [Policy Text Block]

Prepaid Tires, Property, Equipment, and Depreciation

Property and equipment are reported at cost, net of accumulated depreciation. Maintenance and repairs are charged to operations as incurred. New tires are capitalized separately from revenue equipment and are reported separately as “Prepaid tires” in the consolidated balance sheets and amortized over two years. Depreciation for financial statement purposes is computed by the straight-line method for all assets other than new tractors. We recognize depreciation expense on new tractors (excludes tractors acquired through an acquisition) using the declining balance method. Revenue equipment acquired through acquisitions is generally revalued to current market values as of the acquisition date. Assets obtained more than a year prior to the acquisition by the acquired company are depreciated on a straight-line basis aligned with the remaining period of expected use, whereas those obtained less than a year prior are depreciated consistent with newly purchased assets. As acquired equipment is replaced, our fleet returns to our base methods of declining balance depreciation for tractors and straight-line depreciation for trailers. New tractors are depreciated to salvage values of $15,000 while new trailers are depreciated to salvage values of $4,000. Revenue equipment acquired through acquisitions is generally revalued to current market values as of the acquisition date. At March 31, 2026, there were $2.6 million receivables related to equipment sales recorded in other current assets compared to $0.5 million at December 31, 2025.

Earnings Per Share, Policy [Policy Text Block]

Earnings per ShareBasic (loss) earnings per share is based upon the weighted average common shares outstanding during each year. Diluted (loss) earnings per share is based on the basic weighted (loss) earnings per share with additional weighted common shares for common stock equivalents.

Income Tax, Policy [Policy Text Block]

We use the asset and liability method of accounting for income taxes. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statement carrying amount of existing assets and liabilities and their respective tax basis. 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. Such amounts are adjusted, as appropriate, to reflect changes in tax rates expected to be in effect when temporary differences reverse. The effect of a change in tax rates on deferred taxes is recognized in the period that the change is enacted. A valuation allowance is recorded to reduce the Company's deferred tax assets to the amount that is more likely than not to be realized.

Income Tax Uncertainties, Policy [Policy Text Block]

We recognize the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that is greater than 50% likely of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. We record interest and penalties related to unrecognized tax benefits in income tax expense.