Note 10 - Equity Method Investment - TEL's Summarized Financial Information 2 (Details) - USD ($) $ in Thousands	Sep. 30, 2026	Dec. 31, 2025	Sep. 30, 2025	Dec. 31, 2024
Accounts Receivable, after Allowance for Credit Loss	$ 191,700	$ 151,800	$ 150,400	$ 141,600
Transport Enterprise Leasing LLC [Member] \| Location, Statement of Financial Position, Balance [Axis]: cvti:DriversAdvancesAndOtherReceivablesNetOfAllowance
Accounts Receivable, after Allowance for Credit Loss	40	13
Transport Enterprise Leasing LLC [Member] \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:AccruedLiabilitiesCurrent
Accounts payable to TEL	438	460
Transport Enterprise Leasing LLC [Member] \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherAssetsNoncurrent
Investment in TEL	$ 96,490	$ 85,512

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.