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

Non cash accelerated vesting of equity awards share-based compensation cost recognized as a result of an occurrence of an event that accelerates its recognition.

+ References

No definition available.

+ Details

Name:	kex_ShareBasedCompensationArrangementByShareBasedPaymentAwardNoncashAcceleratedVestingOfEquityAwards
Namespace Prefix:	kex_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Average of share based compensation arrangement by share based payment award noncash compensation cost.

+ References

No definition available.

+ Details

Name:	kex_SharebasedCompensationArrangementBySharebasedPaymentAwardNoncashCompensationCost
Namespace Prefix:	kex_
Data Type:	num:perShareItemType
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

- Definition

The compensation expense recognized during the period pertaining to the deferred compensation arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5047-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 710
-SubTopic 10
-Section 30
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6409875&loc=d3e20015-108363

+ Details

Name:	us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3213-108585

+ Details

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

- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Net number of share options (or share units) granted during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of shares for which recognition of compensation cost was accelerated.

+ References

No definition available.

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAcceleratedVestingNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of capitalized and expensed compensation cost from equity-based compensation arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardCompensationCost1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TitleOfIndividualAxis=us-gaap_BoardOfDirectorsChairmanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockMember
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_TargaResourcesCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

SUBSEQUENT EVENTS (Details) $ / shares in Units, $ in Thousands		1 Months Ended
	May 01, 2018 USD ($) TankBarge bbl	Apr. 30, 2018 USD ($) $ / shares shares	Feb. 28, 2018 shares
Stock Options [Member] \| Joseph H. Pyne [Member]
Subsequent Event [Line Items]
Stock options, granted (in shares) \| shares			21,396
Restricted Stock [Member] \| Joseph H. Pyne [Member]
Subsequent Event [Line Items]
RSUs, granted (in shares) \| shares			13,245
Subsequent Event [Member] \| Joseph H. Pyne [Member]
Subsequent Event [Line Items]
One time bonus payment \| $		$ 15,000
Acceleration value of vesting of unvested awards \| $		3,057
Noncash compensation expense \| $		$ 18,057
Value of stock awards granted (in dollars per share) \| $ / shares		$ 0.30
Subsequent Event [Member] \| Stock Options [Member] \| Joseph H. Pyne [Member]
Subsequent Event [Line Items]
Acceleration of vesting of unvested awards (in shares) \| shares		26,819
Subsequent Event [Member] \| Restricted Stock [Member] \| Joseph H. Pyne [Member]
Subsequent Event [Line Items]
Acceleration of vesting of unvested awards (in shares) \| shares		30,643
Subsequent Event [Member] \| Targa [Member]
Subsequent Event [Line Items]
Cash consideration \| $	$ 69,300
Subsequent Event [Member] \| Targa [Member] \| Inland Pressure Tank Barges [Member]
Subsequent Event [Line Items]
Number of maritime vessels acquired \| TankBarge	16
Tank barge barrel capacity \| bbl	258,000