Note 12 - Goodwill and Other Assets - Intangible Assets (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets, Gross	$ 34,000	$ 34,000
Finite-Lived Intangible Assets, Accumulated Amortization	(7,178)	(4,385)
Finite-Lived Intangible Assets, Net	$ 26,822	$ 29,615
Finite-Lived Intangible Asset, Useful Life (Month)	107 months	128 months
Trade Names [Member]
Finite-Lived Intangible Assets, Gross	$ 4,400	$ 4,400
Finite-Lived Intangible Assets, Accumulated Amortization	(1,078)	(440)
Finite-Lived Intangible Assets, Net	$ 3,322	$ 3,960
Finite-Lived Intangible Asset, Useful Life (Month)	15 months	162 months
Trade Names [Member] \| Dedicated [Member]
Finite-Lived Intangible Assets, Gross	$ 2,402	$ 2,402
Finite-Lived Intangible Assets, Accumulated Amortization	(588)	(240)
Finite-Lived Intangible Assets, Net	1,814	2,162
Trade Names [Member] \| Managed Freight [Member]
Finite-Lived Intangible Assets, Gross	1,998	1,998
Finite-Lived Intangible Assets, Accumulated Amortization	(490)	(200)
Finite-Lived Intangible Assets, Net	1,508	1,798
Noncompete Agreements [Member]
Finite-Lived Intangible Assets, Gross	1,400	1,400
Finite-Lived Intangible Assets, Accumulated Amortization	(1,400)	(420)
Finite-Lived Intangible Assets, Net	0	$ 980
Finite-Lived Intangible Asset, Useful Life (Month)		42 months
Noncompete Agreements [Member] \| Dedicated [Member]
Finite-Lived Intangible Assets, Gross	914	$ 914
Finite-Lived Intangible Assets, Accumulated Amortization	(914)	(274)
Finite-Lived Intangible Assets, Net	0	640
Noncompete Agreements [Member] \| Managed Freight [Member]
Finite-Lived Intangible Assets, Gross	486	486
Finite-Lived Intangible Assets, Accumulated Amortization	(486)	(146)
Finite-Lived Intangible Assets, Net	0	340
Customer Relationships [Member]
Finite-Lived Intangible Assets, Gross	28,200	28,200
Finite-Lived Intangible Assets, Accumulated Amortization	(4,700)	(3,525)
Finite-Lived Intangible Assets, Net	$ 23,500	$ 24,675
Finite-Lived Intangible Asset, Useful Life (Month)	120 months	126 months
Customer Relationships [Member] \| Dedicated [Member]
Finite-Lived Intangible Assets, Gross	$ 14,072	$ 14,072
Finite-Lived Intangible Assets, Accumulated Amortization	(2,345)	(1,759)
Finite-Lived Intangible Assets, Net	11,727	12,313
Customer Relationships [Member] \| Managed Freight [Member]
Finite-Lived Intangible Assets, Gross	14,128	14,128
Finite-Lived Intangible Assets, Accumulated Amortization	(2,355)	(1,766)
Finite-Lived Intangible Assets, Net	$ 11,773	$ 12,362

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

+ Details

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

- Definition

Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 928
-SubTopic 340
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6473545&loc=d3e61844-108004

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

+ Details

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

- Definition

Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 926
-SubTopic 20
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=120154696&loc=d3e54445-107959

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

+ Details

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

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_TradeNamesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=cvlg_DedicatedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=cvlg_ManagedFreightMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_NoncompeteAgreementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_CustomerRelationshipsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: