PENSION AND POST-RETIREMENT PLANS - MULTI-EMPLOYER DEFINED BENEFIT PLANS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Multiemployer Plans
Multiemployer Plans, Accumulated Benefit Obligation	$ 216.8
Minimum
Multiemployer Plans
Employer matching contribution to MEBA Pension Trust (as a percent)				11.70%
Multiemployer Benefit Pension Plans
Multiemployer Plans
Contributions of Matson	17.8	$ 13.1	$ 13.1
Multiemployer Benefit Pension Plans | Masters, Mates and Pilots Adjustable Pension Plan
Multiemployer Plans
Contributions of Matson	$ 1.7	1.0	0.8
Multiemployer Benefit Pension Plans | Red Zone | Maximum
Multiemployer Plans
Funded status of multiemployer plan (as a percent)	65.00%
Multiemployer Benefit Pension Plans | Red Zone | M E B A Pension Trust - Defined Benefit Plan
Multiemployer Plans
Contributions of Matson	$ 3.2
Multiemployer Benefit Pension Plans | Red Zone | Alaska Teamster - Employer Pension Plan
Multiemployer Plans
Contributions of Matson	1.5
Multiemployer Benefit Pension Plans | Red Zone | O P E I U Local 153 Pension Plan
Multiemployer Plans
Contributions of Matson	$ 0.1
Multiemployer Benefit Pension Plans | Yellow Zone | Maximum
Multiemployer Plans
Funded status of multiemployer plan (as a percent)	80.00%
Multiemployer Benefit Pension Plans | Yellow Zone | Hawaii Terminals Multiemployer Pension Plan
Multiemployer Plans
Contributions of Matson	$ 4.9	5.1	5.3
Multiemployer Benefit Pension Plans | Yellow Zone | Hawaii Stevedoring Multiemployer Retirement Plan
Multiemployer Plans
Contributions of Matson	$ 2.8	2.9	2.7
Multiemployer Benefit Pension Plans | Green Zone | Minimum
Multiemployer Plans
Funded status of multiemployer plan (as a percent)	80.00%
Multiemployer Benefit Pension Plans | Green Zone | Master Mates And Pilots Pension Plan
Multiemployer Plans
Contributions of Matson	$ 2.2	1.9	2.1
Multiemployer Benefit Pension Plans | Green Zone | M E B A Pension Trust - Defined Benefit Plan
Multiemployer Plans
Contributions of Matson		2.1	2.1
Multiemployer Benefit Pension Plans | Green Zone | O C U Trust Pension Plan
Multiemployer Plans
Contributions of Matson	0.1	0.1	0.1
Multiemployer Benefit Pension Plans | Green Zone | All Alaska Longshore Pension Plan
Multiemployer Plans
Contributions of Matson	0.5
Multiemployer Benefit Pension Plans | Green Zone | Western Conference of Teamsters Pension Plan
Multiemployer Plans
Contributions of Matson	0.8
Multiemployer Health and Benefit Plans
Multiemployer Plans
Contributions of Matson	18.1	11.1	10.5
Multiemployer Health and Benefit Plans | Stevedore Industry Committee Welfare Benefit Plan
Multiemployer Plans
Contributions of Matson	3.8	3.1	2.6
Multiemployer Health and Benefit Plans | O C U Health and Welfare Trust
Multiemployer Plans
Contributions of Matson	0.2	0.2	0.2
Multiemployer Health and Benefit Plans | S U P Welfare Plan, Inc.
Multiemployer Plans
Contributions of Matson	2.9	2.7	2.7
Multiemployer Health and Benefit Plans | M E B A Medical and Benefits Plan
Multiemployer Plans
Contributions of Matson	2.2	1.8	1.7
Multiemployer Health and Benefit Plans | M F O W Welfare Fund
Multiemployer Plans
Contributions of Matson	1.3	1.2	1.2
Multiemployer Health and Benefit Plans | A R A Pension and Welfare Plan
Multiemployer Plans
Contributions of Matson	0.5	0.5	0.5
Multiemployer Health and Benefit Plans | Masters, Mates and Pilots Health and Benefit Plan
Multiemployer Plans
Contributions of Matson	2.3	$ 1.6	$ 1.6
Multiemployer Health and Benefit Plans | Seafarers Health and Benefits Plan
Multiemployer Plans
Contributions of Matson	1.8
Multiemployer Health and Benefit Plans | Alaska Teamster - Employer Welfare Trust
Multiemployer Plans
Contributions of Matson	1.2
Multiemployer Health and Benefit Plans | All Alaska Longshore Health and Welfare Trust Fund
Multiemployer Plans
Contributions of Matson	1.3
Multiemployer Health and Benefit Plans | Western Teamsters Welfare Trust
Multiemployer Plans
Contributions of Matson	$ 0.6