Refers to the number of maritime (seagoing) vessels acquired.

No definition available.

Name:	kex_NumberOfMaritimeVesselsAcquired
Namespace Prefix:	kex_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Refers to the aggregate carrying capacity of a quantity of tank barges as measured in number of barrels.

+ References

No definition available.

+ Details

Name:	kex_TankBargeAggregateBarrelCapacity
Namespace Prefix:	kex_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

Refers to the carrying capacity of tank barges as measured in number of barrels.

+ References

No definition available.

+ Details

Name:	kex_TankBargeBarrelCapacity
Namespace Prefix:	kex_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsAdditionalDisclosuresAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireBusinessesGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=kex_InlandTowboatsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=kex_CenacMarineServicesLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=kex_BarrelTankBargesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=kex_TugboatsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Subsequent Events (Details) $ in Millions	Jan. 29, 2019 USD ($) bbl TankBarge Towboat Tugboat	Nov. 30, 2018 Towboat
Inland Towboats [Member]
Acquisitions [Abstract]
Number of maritime vessels acquired \| Towboat		1
Subsequent Event [Member] \| Cenac Marine Services, LLC [Member]
Acquisitions [Abstract]
Cash paid for acquisition \| $	$ 244
Subsequent Event [Member] \| Cenac Marine Services, LLC [Member] \| Inland Barrel Tank Barges [Member]
Acquisitions [Abstract]
Number of maritime vessels acquired \| TankBarge	63
Tank barge barrel capacity (in barrels) \| bbl	30,000
Aggregate tank barge barrel capacity (in barrels) \| bbl	1,900,000
Subsequent Event [Member] \| Cenac Marine Services, LLC [Member] \| Inland Towboats [Member]
Acquisitions [Abstract]
Number of maritime vessels acquired \| Towboat	34
Subsequent Event [Member] \| Cenac Marine Services, LLC [Member] \| Offshore Tugboats [Member]
Acquisitions [Abstract]
Number of maritime vessels acquired \| Tugboat	2