Significant Accounting Policies (Policies)	6 Months Ended
Significant Accounting Policies (Policies)	Jun. 30, 2019
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation The condensed consolidated financial statements include the accounts of Covenant Transportation Group, Inc., a Nevada holding company, and its wholly owned subsidiaries. References in this report to "we," "us," "our," the "Company," and similar expressions refer to Covenant Transportation Group, Inc. and its wholly owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America for interim financial information and with the instructions to Form 10 -Q and Article 10 of Regulation S- X promulgated under the Securities Act of 1933. In preparing financial statements, it is necessary for management to make assumptions and estimates affecting the amounts reported in the condensed consolidated financial statements and related notes. These estimates and assumptions are developed based upon all information available. Actual results could differ from estimated amounts. In the opinion of management, the accompanying financial statements include all adjustments that are necessary for a fair presentation of the results for the interim periods presented, such adjustments being of a normal recurring nature. Certain information and footnote disclosures have been condensed or omitted pursuant to such rules and regulations. The December 31, 2018 , condensed consolidated balance sheet was derived from our audited balance sheet as of that date. Our operating results are subject to seasonal trends when measured on a quarterly basis; therefore operating results for the three months ended June 30, 2019 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018 . These condensed consolidated financial statements and notes thereto should be read in conjunction with the consolidated financial statements and notes thereto included in our Form 10 -K for the year ended December 31, 2018 . Results of operations in interim periods are not necessarily indicative of results to be expected for a full year.
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements Accounting Standards adopted In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016 - 02, which establishes Topic 842 to replace Topic 840 regarding accounting for leases. Topic 842 requires lessees to recognize a right-of-use asset and a lease liability for most leases on the balance sheet. Leases that were previously described as capital leases are now called finance leases, and operating leases with a term of at least twelve months are now required to be recorded on the balance sheet. We adopted this standard on January 1, 2019 using the modified retrospective approach. In July 2018, FASB issued ASU 2018 - 11, which provides an optional transition method allowing application of Topic 842 as of the adoption date and recognition of a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption, with no restatement of comparative prior periods. We have adopted the standard using this optional transition method. Within Topic 842, FASB has provided a number of practical expedients for applying the new lease standard in relation to leases that commenced prior to the standard's effective date. We have elected the package of practical expedients which allowed us, among other things, to carry forward the operating and capital lease classifications from Topic 840 to the new operating and finance lease classifications under Topic 842. The adoption of this ASU resulted in the initial recognition of operating lease assets and liabilities totaling approximately $41.0 million, comprised of $15.3 million of current liabilities and $25.7 million of long-term operating lease obligations.
Property, Plant and Equipment, Policy [Policy Text Block]	Property and Equipment Property and equipment is stated at cost less accumulated depreciation. Depreciation for book purposes is determined using the straight-line method over the estimated useful lives of the assets, while depreciation for tax purposes is generally recorded using an accelerated method. Depreciation of revenue equipment is our largest item of depreciation. We have historically depreciated new tractors (excluding day cabs) over five years to salvage values of approximately 15% of their cost. We generally depreciate new trailers over seven years for refrigerated trailers and ten years for dry van trailers to salvage values of approximately 25% of their cost. We annually review the reasonableness of our estimates regarding useful lives and salvage values of our revenue equipment and other long-lived assets based upon, among other things, our experience with similar assets, conditions in the used revenue equipment market, and prevailing industry practice. Changes in the useful life or salvage value estimates, or fluctuations in market values that are not reflected in our estimates, could have a material effect on our results of operations. Gains and losses on the disposal of revenue equipment are included in depreciation expense in the consolidated statements of operations.
Lessee, Leases [Policy Text Block]	Leases At the commencement date of a new lease agreement with contractual terms longer than twelve months, we recognize a right-of-use asset and a lease liability and categorize the lease as either finance or operating. Certain lease agreements have lease and nonlease components, and we have elected to account for these components separately. Right-of-use assets and lease liabilities are initially recorded based on the present value of lease payments over the term of the lease. When the rate implicit in the lease is readily determinable, this rate is used for calculating the present value of remaining lease payments; otherwise, our incremental borrowing rate is used. Right-of-use assets also include prepaid lease expenses and initial direct costs of executing the leases, which are reduced by landlord incentives. Options to extend or terminate a lease agreement are included in or excluded from the lease term, respectively, when those options are reasonably certain to be exercised. Right-of-use assets are tested for impairment in the same manner as long-lived assets. Right-of-use assets are included in net property and equipment. For finance leases, right-of-use assets are amortized on a straight-line basis over the shorter of the expected useful life or the lease term, and the carrying amount of the lease liability is adjusted to reflect interest expense, which is recorded in interest expense, net. Operating lease right-of-use assets are amortized over the lease term on a straight-line basis, and the lease liability is measured at the present value of the remaining lease payments. Variable lease payments not included in the lease liability for mileage charges on leased revenue equipment are expensed as incurred. Operating lease costs are recognized on a straight-line basis over the term of the lease within operating expenses.