Note 7 - Debt (Details Textual) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2018	Dec. 31, 2017
Line of Credit Facility, Maximum Borrowing Capacity	$ 95,000
Line of Credit Facility, Maximum Increase in Borrowing Capacity	$ 50,000
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.25%
Percent of Eligible Accounts Receivable	85.00%
Percent of Appraised Net Orderly Liquidation, Value of Eligible Revenue Equipment	85.00%
Percent of Net Book Value of Eligible Revenue Equipment	95.00%
Line of Credit Facility, Availability as Percentage of Revolver Commitment	35.00%
Line of Credit Facility, Revolver Commitment, Amount	$ 25,000
Percent of Appraised Fair Market Value of Eligible Real Estate	75.00%
Long-term Line of Credit, Total	$ 4,000
Letters of Credit Outstanding, Amount	32,800	$ 32,900
Line of Credit Facility, Remaining Borrowing Capacity	57,900
Fixed Charge Coverage Requirement	0	$ 0
Debt, Secured with a Cross Default Feature	128,000
Commodity Contract Asset, Current	$ 800
Federal Funds Rate [Member] \| Base Rate Loans [Member]
Debt Instrument, Basis Spread on Variable Rate	0.50%
London Interbank Offered Rate (LIBOR) [Member]
Long-term Line of Credit, Total	$ 0
London Interbank Offered Rate (LIBOR) [Member] \| Base Rate Loans [Member]
Debt Instrument, Basis Spread on Variable Rate	1.00%
Applicable Margin [Member] \| Base Rate Loans [Member] \| Minimum [Member]
Debt Instrument, Basis Spread on Variable Rate	0.50%
Applicable Margin [Member] \| Base Rate Loans [Member] \| Maximum [Member]
Debt Instrument, Basis Spread on Variable Rate	1.00%
Applicable Margin [Member] \| LIBOR [Member] \| Minimum [Member]
Debt Instrument, Basis Spread on Variable Rate	1.50%
Applicable Margin [Member] \| LIBOR [Member] \| Maximum [Member]
Debt Instrument, Basis Spread on Variable Rate	2.00%
Base Rate Loans [Member]
Long-term Line of Credit, Total	$ 4,000
Debt Instrument, Interest Rate, Stated Percentage	5.30%
Letter of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 95,000
Swing Line Sub Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 10,000
Percent of Aggregate Commitments under Credit Facility	10.00%

Debt secured with a cross default feature.

No definition available.

Name:	cvti_DebtSecuredWithACrossDefaultFeature
Namespace Prefix:	cvti_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the fixed charge coverage requirement.

+ References

No definition available.

+ Details

Name:	cvti_FixedChargeCoverageRequirement
Namespace Prefix:	cvti_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The availability of line of credit facility as percentage of the revolver commitment.

+ References

No definition available.

+ Details

Name:	cvti_LineOfCreditFacilityAvailabilityAsPercentageOfRevolverCommitment
Namespace Prefix:	cvti_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of credit facility's maximum increase in borrowing capacity as long as no event of default exists.

+ References

No definition available.

+ Details

Name:	cvti_LineOfCreditFacilityMaximumIncreaseInBorrowingCapacity
Namespace Prefix:	cvti_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The revolver commitment amount.

+ References

No definition available.

+ Details

Name:	cvti_LineOfCreditFacilityRevolverCommitmentAmount
Namespace Prefix:	cvti_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The percent of the lenders' aggregate commitments under the credit facility.

+ References

No definition available.

+ Details

Name:	cvti_PercentOfAggregateCommitmentsUnderCreditFacility
Namespace Prefix:	cvti_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percent of appraised fair market value of eligible real estate used in the calculation of borrowing base.

+ References

No definition available.

+ Details

Name:	cvti_PercentOfAppraisedFairMarketValueOfEligibleRealEstate
Namespace Prefix:	cvti_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The percent of appraised net orderly liquidation value of eligible revenue equipment used in the calculation of borrowing base.

+ References

No definition available.

+ Details

Name:	cvti_PercentOfAppraisedNetOrderlyLiquidationValueOfEligibleRevenueEquipment
Namespace Prefix:	cvti_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percent of the eligible accounts receivable used in the calculation of borrowing base.

+ References

No definition available.

+ Details

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Namespace Prefix:	cvti_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percent of net book value of eligible revenue equipment used in the calculation of borrowing base.

+ References

No definition available.

+ Details

Name:	cvti_PercentOfNetBookValueOfEligibleRevenueEquipment
Namespace Prefix:	cvti_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying amount as of the balance sheet date of the asset arising from commodity contracts such as futures contracts tied to the movement of a particular commodity, which are expected to be converted into cash or otherwise disposed of within a year or the normal operating cycle, if longer.

+ References

+ Details

Name:	us-gaap_CommodityContractAssetCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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- Details

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- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LetterOfCreditMember
Namespace Prefix:
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- Details

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