Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash Flows From Operating Activities:
Net income	$ 109.0	$ 231.0	$ 81.4
Reconciling adjustments:
Depreciation and amortization	94.4	101.2	97.1
Deferred income taxes	29.3	(127.9)	24.7
(Gain) Loss on disposal of property and equipment	(1.9)	3.0	0.9
Share-based compensation expense	12.1	11.1	11.2
Equity in income of Terminal Joint Venture	(36.8)	(28.2)	(15.8)
Distribution from Terminal Joint Venture	42.0	17.5
Tax benefit from equity issuance			2.2
Tax benefit from stock-based compensation			(0.3)
Changes in assets and liabilities:
Accounts receivable, net	(29.1)	(5.1)	14.4
Deferred dry-docking payments	(19.2)	(54.6)	(59.2)
Deferred dry-docking amortization	37.4	46.2	38.9
Prepaid expenses and other assets	4.2	14.4	(13.6)
Accounts payable, accruals and other liabilities	71.2	20.4	2.1
Other long-term liabilities	(7.6)	(4.1)	(26.2)
Net cash provided by operating activities	305.0	224.9	157.8
Cash Flows From Investing Activities:
Capitalized vessel construction expenditures	(338.6)	(252.0)	(94.5)
Other capital expenditures	(62.6)	(55.0)	(84.9)
Proceeds from (payments for) disposal of property and equipment	136.3	(0.2)	2.5
Cash deposits into Capital Construction Fund	(340.0)	(171.4)	(123.4)
Withdrawals from Capital Construction Fund	340.9	201.7	92.2
Proceeds from sale of other investments	3.7
Payments for membership interests in Span Alaska, net of cash acquired			(112.6)
Net cash used in investing activities	(260.3)	(276.9)	(320.7)
Cash Flows From Financing Activities:
Proceeds from issuance of debt			275.0
Repayments of debt	(30.0)	(30.0)	(20.5)
Repayment of capital leases	(0.7)	(1.8)	(1.7)
Proceeds from revolving credit facility	963.9	469.0	1,103.0
Repayments of revolving credit facility	(933.9)	(319.0)	(1,048.0)
Payment of financing costs		(1.7)
Proceeds from issuance of capital stock	0.7	1.9	1.2
Dividends paid	(35.4)	(33.8)	(32.2)
Repurchase of Matson common stock		(19.3)	(38.0)
Tax withholding related to net share settlements of restricted stock units	(4.6)	(7.4)	(5.9)
Tax benefit from stock-based compensation			0.3
Payments of Span Alaska debt			(81.9)
Net cash (used in) provided by financing activities	(40.0)	57.9	151.3
Net Increase (Decrease) in Cash, Cash Equivalents and Restricted Cash	4.7	5.9	(11.6)
Cash, Cash Equivalents and Restricted Cash, Beginning of the Year	19.8	13.9	25.5
Cash, Cash Equivalents and Restricted Cash, End of the Year	24.5	19.8	13.9
Reconciliation of Cash, Cash Equivalents, and Restricted Cash, at End of the Year:
Cash and Cash Equivalents	19.6	19.8	13.9
Restricted Cash	4.9
Cash, Cash Equivalents and Restricted Cash, End of the Year	24.5	19.8	13.9
Supplemental Cash Flow Information:
Interest paid, net of capitalized interest	18.3	23.9	21.6
Income tax paid, net of income tax refunds	5.2	2.6	15.6
Non-cash Information:
Capital expenditures included in accounts payable, accruals and other liabilities	$ 4.1	$ 1.2	$ 4.1