ACQUISITIONS (Details)				1 Months Ended		9 Months Ended
	Jun. 30, 2016 USD ($) bbl	Jun. 02, 2016 USD ($) Tugboat	Apr. 15, 2016 USD ($) TankBarge Towboat bbl	Jul. 31, 2016 USD ($)	May 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Goodwill acquired						$ 587,703,000	$ 586,718,000
SEACOR Holdings Inc. [Member]
Business Acquisition [Line Items]
Purchase price			$ 91,681,000
Number of inland barrel tank barges | TankBarge			27
Barrel tank barges | bbl			30,000
Number of inland towboats | Towboat			13
Number of inland barrel tank barges under construction | TankBarge			1
Number of inland towboats under construction | Towboat			1
Cash paid for acquisition			$ 79,200,000	$ 4,500,000	$ 1,800,000
Expected payment to be made for acquisition						$ 2,500,000
Ownership transferred, value			3,681,000
Goodwill acquired			985,000
Intangible assets acquired			0
SEACOR Holdings Inc. [Member] | New Construction [Member]
Business Acquisition [Line Items]
Amount holdback during acquisition			7,000,000
SEACOR Holdings Inc. [Member] | Maintenance and Repairs [Member]
Business Acquisition [Line Items]
Amount holdback during acquisition			$ 1,800,000
SEACOR Holdings Inc. [Member] | Inland Tank Barges [Member]
Business Acquisition [Line Items]
Average age of property						10 years
Crosby Marine Transportation LLC [Member]
Business Acquisition [Line Items]
Cash paid for acquisition		$ 26,450,000
Number of coastal tugboats purchased | Tugboat		4
Crosby Marine Transportation LLC [Member] | Coastal Tugboats [Member]
Business Acquisition [Line Items]
Average age of property						13 years
TD Equipment Finance, Inc. [Member]
Business Acquisition [Line Items]
Barrel tank barges | bbl	80,000
Cash paid for acquisition	$ 13,682,000