Matson (MATX) 10-K 26 Feb 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 19, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2020
Entity File Number	001-34187
Entity Registrant Name	Matson, Inc.
Entity Incorporation, State or Country Code	HI
Entity Tax Identification Number	99-0032630
Entity Address, Address Line One	1411 Sand Island Parkway
Entity Address, City or Town	Honolulu
Entity Address, State or Province	HI
Entity Address, Postal Zip Code	96819
City Area Code	808
Local Phone Number	848-1211
Title of 12(b) Security	Common Stock, without par value
Trading Symbol	MATX
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		43,435,106
Entity Public Float			$ 1,233,205,504
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Central Index Key	0000003453
Amendment Flag	false
ICFR Auditor Attestation Flag	true

Consolidated Statements of Inco

Consolidated Statements of Income and Comprehensive Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Revenue:
Total Operating Revenue	$ 2,383.3	$ 2,203.1	$ 2,222.8
Costs and Expenses:
Operating costs	(1,904.3)	(1,878)	(1,875)
Income from SSAT	26.3	20.8	36.8
Selling, general and administrative	(225)	(216.8)	(220.8)
Total Costs and Expenses	(2,103)	(2,074)	(2,059)
Operating Income	280.3	129.1	163.8
Interest expense	(27.4)	(22.5)	(18.7)
Other income (expense), net	6.1	1.2	2.6
Income before Income Taxes	259	107.8	147.7
Income taxes	(65.9)	(25.1)	(38.7)
Net Income	193.1	82.7	109
Other Comprehensive Income (Loss), Net of Income Taxes:
Net Income	193.1	82.7	109
Other Comprehensive Income (Loss):
Amortization of prior service cost	(4.7)	(4.5)	(4.7)
Amortization of net loss (gain)	(9.4)	2.7	1.1
Other adjustments	0.2	(0.6)
Total Other Comprehensive Income (Loss)	(13.9)	(2.4)	(3.6)
Comprehensive Income	$ 179.2	$ 80.3	$ 105.4
Basic Earnings Per-Share: (in dollars per share)	$ 4.48	$ 1.93	$ 2.55
Diluted Earnings Per-Share: (in dollars per share)	$ 4.44	$ 1.91	$ 2.53
Weighted Average Number of Shares Outstanding:
Basic	43.1	42.8	42.7
Diluted	43.5	43.3	43
Ocean Transportation
Operating Revenue:
Total Operating Revenue	$ 1,853.9	$ 1,666.6	$ 1,641.3
Logistics
Operating Revenue:
Total Operating Revenue	$ 529.4	$ 536.5	$ 581.5

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Current Assets:
Cash and cash equivalents	$ 14.4	$ 21.2
Accounts receivable, net of allowance for credit loss of $6.3 million and $4.3 million, respectively	253.4	205.9
Prepaid expenses and other assets	38.1	62.5
Total current assets	305.9	289.6
Long-term Assets:
Investment in SSAT	48.7	76.2
Property and equipment, net	1,689.9	1,598.1
Operating lease right of use assets	251.4	256.1
Goodwill	327.8	327.8
Intangible assets, net	192	202.9
Deferred dry-docking costs, net	51.9	56.9
Other long-term assets	33	37.8
Total long-term assets	2,594.7	2,555.8
Total Assets	2,900.6	2,845.4
Current Liabilities:
Current portion of debt	59.2	48.4
Accounts payable and accruals	283.1	235.7
Operating lease liabilities	72.4	66.6
Other liabilities	96.8	86
Total current liabilities	511.5	436.7
Long-term Liabilities:
Long-term debt, net of deferred loan fees	685.6	910
Long-term operating lease liabilities	186.9	198
Deferred income taxes	389.6	337.6
Other long-term liabilities	165.8	157.4
Total long-term liabilities	1,427.9	1,603
Commitments and Contingencies (see Note 17)
Shareholders' Equity:
Common stock - common stock without par value; authorized, 150.0 million shares ($0.75 stated value per share); outstanding, 43.2 million shares in 2020 and 42.9 million shares in 2019	32.4	32.2
Additional paid in capital	321.5	306.2
Accumulated other comprehensive loss, net	(50.8)	(36.9)
Retained earnings	658.1	504.2
Total shareholders' equity	961.2	805.7
Total Liabilities and Shareholders' Equity	$ 2,900.6	$ 2,845.4

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Millions, $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Consolidated Balance Sheets
Accounts receivable, allowance for credit loss	$ 6.3	$ 4.3
Common stock, shares authorized	150	150
Common stock, stated value (in dollars per share)	$ 0.75	$ 0.75
Common stock, shares outstanding	43.2	42.9

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flows From Operating Activities:
Net income	$ 193.1	$ 82.7	$ 109
Reconciling adjustments:
Depreciation and amortization	114.9	100.4	94.4
Amortization of operating lease right of use assets	74.8	60.7
Deferred income taxes	52.1	23.6	29.3
Loss (Gain) on disposal of property and equipment	2.8	(1.4)	(1.9)
Share-based compensation expense	18.8	11.3	12.1
Income from SSAT	(26.3)	(20.8)	(36.8)
Distributions from SSAT	55.4	25.2	42
Changes in assets and liabilities:
Accounts receivable, net	(48)	17.8	(29.1)
Deferred dry-docking payments	(16.8)	(25.9)	(19.2)
Deferred dry-docking amortization	25.1	34.3	37.4
Prepaid expenses and other assets	21.9	24.5	4.2
Accounts payable, accruals and other liabilities	44.8	(13.9)	71.2
Operating lease liabilities	(75.9)	(59.9)
Other long-term liabilities	(6.9)	(9.8)	(7.6)
Net cash provided by operating activities	429.8	248.8	305
Cash Flows From Investing Activities:
Capitalized vessel construction expenditure	(87.8)	(219.1)	(338.6)
Other capital expenditures	(104.5)	(91.2)	(62.6)
Proceeds from disposal of property and equipment	15.3	3.4	136.3
Cash deposits into Capital Construction Fund	(132.4)	(96.2)	(340)
Withdrawals from Capital Construction Fund	132.4	96.2	340.9
Proceeds from sale of other investments			3.7
Net cash used in investing activities	(177)	(306.9)	(260.3)
Cash Flows From Financing Activities:
Proceeds from issuance of debt	325.5
Repayments of debt	(216.5)	(42.1)	(30.7)
Proceeds from revolving credit facility	648	622.1	963.9
Repayments of revolving credit facility	(955.3)	(478)	(933.9)
Payment of financing costs	(18.5)
Proceeds from issuance of common stock	0.1	0.3	0.7
Dividends paid	(39.2)	(37.2)	(35.4)
Tax withholding related to net share settlements of restricted stock units	(5.6)	(3.1)	(4.6)
Net cash provided by (used in) financing activities	(261.5)	62	(40)
Net (Decrease) Increase in Cash, Cash Equivalents and Restricted Cash	(8.7)	3.9	4.7
Cash, Cash Equivalents and Restricted Cash, Beginning of the Year	28.4	24.5	19.8
Cash, Cash Equivalents and Restricted Cash, End of the Year	19.7	28.4	24.5
Reconciliation of Cash, Cash Equivalents, and Restricted Cash, at End of the Year:
Total Cash, Cash Equivalents and Restricted Cash, End of the Year	28.4	24.5	24.5
Supplemental Cash Flow Information:
Interest paid, net of capitalized interest	26.2	22	18.3
Income tax paid, net of income tax refunds	(16.1)	(24.2)	5.2
Non-cash Information:
Capital expenditures included in accounts payable, accruals and other liabilities	$ 24.7	$ 8.5	$ 4.1

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Common Stock	Additional Paid In Capital	Accumulated Other Comprehensive Income (Loss)	Retained EarningsAdjustmentSSAT	Retained EarningsAdjustment	Retained Earnings	AdjustmentSSAT	Adjustment	Total
Balance at the beginning of the period at Dec. 31, 2017	$ 31.9	$ 289.7	$ (24.9)			$ 380.5			$ 677.2
Balance (in shares) at Dec. 31, 2017	42.5
Increase (Decrease) in Stockholders' Equity
Net income						109			109
Other comprehensive income (loss), net of tax			(9.6)			6			(3.6)
Share-based compensation		12.1							12.1
Shares issued, net of shares withheld for employee taxes	$ 0.1	(4)							(3.9)
Shares issued, net of shares withheld for employee taxes (in shares)	0.2
Shares repurchased						(0.1)			(0.1)
Dividends						(35.4)			(35.4)
Balance at the end of the period at Dec. 31, 2018	$ 32	297.8	(34.5)			460			755.3
Balance (in shares) at Dec. 31, 2018	42.7
Increase (Decrease) in Stockholders' Equity
Net income						82.7			82.7
Other comprehensive income (loss), net of tax			(2.4)						(2.4)
Share-based compensation		11.3							11.3
Shares issued, net of shares withheld for employee taxes	$ 0.2	(2.9)							(2.7)
Shares issued, net of shares withheld for employee taxes (in shares)	0.2
Dividends						(37.3)			(37.3)
Balance at the end of the period at Dec. 31, 2019	$ 32.2	306.2	(36.9)	$ (5.6)	$ 4.4	504.2	$ (5.6)	$ 4.4	$ 805.7
Balance (in shares) at Dec. 31, 2019	42.9								42.9
Increase (Decrease) in Stockholders' Equity
Net income						193.1			$ 193.1
Other comprehensive income (loss), net of tax			(13.9)						(13.9)
Share-based compensation		18.8							18.8
Shares issued, net of shares withheld for employee taxes	$ 0.2	(3.5)				(2.2)			(5.5)
Shares issued, net of shares withheld for employee taxes (in shares)	0.3
Equity interest in SSAT						2.2			2.2
Dividends						(39.2)			(39.2)
Balance at the end of the period at Dec. 31, 2020	$ 32.4	$ 321.5	$ (50.8)			$ 658.1			$ 961.2
Balance (in shares) at Dec. 31, 2020	43.2								43.2

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Consolidated Statement of Stockholders' Equity
Dividends (per share)	$ 0.90	$ 0.86	$ 0.82

DESCRIPTION OF THE BUSINESS

DESCRIPTION OF THE BUSINESS	12 Months Ended
	Dec. 31, 2020
DESCRIPTION OF THE BUSINESS
DESCRIPTION OF THE BUSINESS	1. DESCRIPTION OF THE BUSINESS ​ Matson, Inc., a holding company incorporated in the State of Hawaii, and its subsidiaries (“Matson” or the “Company”), is a leading provider of ocean transportation and logistics services. The Company consists of segments, Ocean Transportation and Logistics. For financial information on the Company’s reportable segments for the three years ended December 31, 2020, see Note 3. ​ Ocean Transportation: Matson’s Ocean Transportation business is conducted through Matson Navigation Company, Inc. (“MatNav”), a wholly-owned subsidiary of Matson, Inc. Founded in 1882, MatNav provides a vital lifeline of ocean freight transportation services to the domestic non-contiguous economies of Hawaii, Alaska and Guam, and to other island economies in Micronesia. MatNav also operates two premium, expedited services from China to Long Beach, California, and provides services to Okinawa, Japan and various islands in the South Pacific, and operates an international export service from Dutch Harbor to Asia. In addition, subsidiaries of MatNav provide stevedoring, refrigerated cargo services, inland transportation and other terminal services for MatNav and other ocean carriers on the Hawaiian islands of Oahu, Hawaii, Maui and Kauai, and in the Alaska locations of Anchorage, Kodiak and Dutch Harbor. ​ Matson has a 35 percent ownership interest in SSA Terminals, LLC, a joint venture between Matson Ventures, Inc., a wholly-owned subsidiary of MatNav, and SSA Ventures, Inc., a subsidiary of Carrix, Inc. (“SSAT”). SSAT currently provides terminal and stevedoring services to various carriers at facilities dedicated for MatNav’s use. Matson records its share of income from SSAT in costs and expenses in the Consolidated Statements of Income and Comprehensive Income, and within the Ocean Transportation segment due to the nature of SSAT’s operations. ​ Logistics: Matson’s Logistics business is conducted through Matson Logistics, Inc. (“Matson Logistics”), a wholly-owned subsidiary of MatNav. Established in 1987, Matson Logistics is an asset-light business that provides a variety of logistics services to its customers including: (i) multimodal transportation brokerage of domestic and international rail intermodal services, long-haul and regional highway trucking services, specialized hauling, flat-bed and project services, less-than-truckload services, and expedited freight services (collectively, “Transportation Brokerage” services); (ii) less-than-container load (“LCL”) consolidation and freight forwarding services (collectively, “Freight Forwarding” services); (iii) warehousing and distribution services; and (iv) supply chain management, non-vessel operating common carrier (“NVOCC”) freight forwarding and other services. ​

SIGNIFICANT ACCOUNTING POLICIES

SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2020
SIGNIFICANT ACCOUNTING POLICIES
SIGNIFICANT ACCOUNTING POLICIES	2. SIGNIFICANT ACCOUNTING POLICIES ​ Principles of Consolidation: The Consolidated Financial Statements include the accounts of Matson, Inc. and all wholly-owned subsidiaries, after elimination of intercompany amounts and transactions. Significant investments in businesses, partnerships, and limited liability companies in which the Company does not have a controlling financial interest, but has the ability to exercise significant influence, are accounted for under the equity method. The Company accounts for its investment in SSAT using the equity method of accounting (see Note 4). ​ Fiscal Year: The year end for Matson is December 31. The period end for MatNav occurred on the last Friday in December, except for Matson Logistics Warehousing, Inc. and Matson South Pacific Holdco Limited whose period closed on December 31. Included in these Consolidated Financial Statements are 52 weeks in the 2020, 2019 and 2018 fiscal years for MatNav. ​ Foreign Currency Transactions: The United States (U.S.) dollar is the functional currency for substantially all of the financial statements of the Company’s foreign subsidiaries. Foreign currency denominated assets and liabilities of the Company’s foreign subsidiaries are translated into U.S. dollars at exchange rates existing at the respective balance sheet dates. Translation adjustments resulting from fluctuations in exchange rates are recorded as a component of accumulated other comprehensive loss (gain) within shareholders’ equity. The Company translates the result of operations of its foreign subsidiaries at the average exchange rate during the respective periods. Gains and losses resulting from foreign currency transactions are included in Costs and Expenses in the Consolidated Statements of Income and Comprehensive Income. ​ Use of Estimates: The preparation of the Consolidated Financial Statements in conformity with accounting principles generally accepted in the U.S. requires management to make estimates and assumptions that affect the amounts reported. Estimates and assumptions are used for, but not limited to: impairment of investments; impairment of long-lived assets, intangible assets and goodwill; capitalized interest; allowance for doubtful accounts; legal contingencies; insurance reserves and other related liabilities; accrual estimates; pension and post-retirement estimates; multi-employer withdrawal liabilities; operating lease assets and liabilities; and income taxes. Future results could be materially affected if actual results differ from these estimates and assumptions. ​ Cash, Cash Equivalents and Restricted Cash: Cash equivalents consist of highly-liquid investments with original maturities of three months or less. The Company carries these investments at cost, which approximates fair value. Outstanding checks in excess of funds on deposit totaled $19.9 million and $13.8 million at December 31, 2020 and 2019, respectively, and are included in current liabilities in the Consolidated Balance Sheets. Restricted cash relates to amounts that are subject to contractual restrictions and are not readily available. At December 31, 2020 and 2019, restricted cash was $5.3 million and $7.2 million, respectively, and are included in prepaid expenses and other assets in the Consolidated Balance Sheets. ​ Accounts Receivable, net: Accounts receivable represent amounts due from trade customers arising in the normal course of business. Accounts receivable are shown net of allowance for doubtful accounts receivable in the Consolidated Balance Sheets. Allowance for doubtful accounts receivable is established by management based on estimates of collectability. Estimates of collectability are principally based on an evaluation of the current financial condition of the customer and the potential risks to collection, the customer’s payment history, expected future credit losses and other factors which are regularly monitored by the Company. ​ Changes in the allowance for doubtful accounts receivable for the three years ended December 31, 2020, 2019 and 2018 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at ​ Write-offs Balance at Year (in millions) Beginning of Year Expense (1) and Other End of Year 2020 ​ $ 4.3 ​ $ 2.9 ​ $ (0.9) ​ $ 6.3 ​ 2019 ​ $ 4.8 ​ $ 0.6 ​ $ (1.1) ​ $ 4.3 ​ 2018 ​ $ 4.6 ​ $ 0.8 ​ $ (0.6) ​ $ 4.8 ​ (1) Expense is shown net of amounts recovered from previously reserved doubtful accounts. ​ Prepaid Expenses and Other Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, Prepaid Expenses and Other Assets (in millions) 2020 2019 Prepaid fuel ​ $ 10.8 ​ $ 13.7 ​ Prepaid insurance and insurance related receivables ​ 7.5 ​ 13.4 ​ Prepaid operating expenses ​ ​ 5.4 ​ ​ 5.7 ​ Restricted cash - vessel construction obligations ​ ​ 5.3 ​ ​ 7.2 ​ Income tax receivables ​ ​ 0.3 ​ ​ 12.8 ​ Other ​ 8.8 ​ 9.7 ​ Total ​ $ 38.1 ​ $ 62.5 ​ ​ Deferred Loan Fees: The Company records deferred loan fees, excluding those related to the revolving credit facility, as a reduction to Total Debt in the Company’s Consolidated Balance Sheets in accordance with Accounting Standards Update (“ASU”) 2015-03, Interest-Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs (“ASU 2015-03”). These costs are being amortized over the life of the related debt using the effective interest method (see Note 8). ​ Deferred loan fees related to the Company’s revolving credit facility are recorded in other long-term assets in the Company’s Consolidated Balance Sheets, and are amortized using the straight-line method as the difference between that and the use of the effective interest method is not material. Other Long-Term Assets: Other long-term assets consist of the following at December 31, 2020 and 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, Other Long-Term Assets (in millions) 2020 2019 Vessel and equipment spare parts ​ $ 11.5 ​ $ 12.4 ​ Insurance related receivables ​ ​ 10.5 ​ ​ 10.6 ​ Deferred loan fees ​ 2.7 ​ 2.1 ​ Cloud computing software costs ​ 2.4 ​ — ​ Income tax receivables ​ ​ 2.1 ​ ​ 11.5 ​ Other ​ ​ 3.8 ​ ​ 1.2 ​ Total ​ $ 33.0 ​ $ 37.8 ​ ​ Property and Equipment: Property and equipment is stated at cost. Property and equipment is depreciated using the straight-line method over the estimated useful lives of the assets. The estimated useful lives of property and equipment range up to the following maximum life: ​ ​ ​ ​ ​ Classification Life Vessels 40 years ​ Machinery and equipment 30 years ​ Terminal facilities 35 years ​ ​ Capitalized Interest: The Company capitalizes interest costs during the period the qualified assets are being readied for their intended use. The Company determined that the vessel construction costs are considered qualifying assets for the purposes of capitalizing interest on these assets. The amount of capitalized interest is calculated based on the amount of payments incurred related to the construction of these vessels using a weighted average interest rate. The weighted average interest rate is determined using the Company’s average borrowings outstanding during the period. Capitalized interest is included in vessel construction in progress in property and equipment in the Company’s Consolidated Balance Sheets (see Note 5). During the years ended December 31, 2020, 2019 and 2018, the Company capitalized $7.4 million, $15.6 million and $18.7 million of interest related to the construction of new vessels, respectively. ​ Leases: The Company adopted Accounting Standards Codification (“ASC”) 842, Leases 1, 2019. ASC 842 ​ Deferred Dry-docking Costs: U.S. flagged vessels must meet specified seaworthiness standards established by U.S. Coast Guard rules and classification society rules. These standards require U.S. flagged vessels to undergo between them. However, U.S. flagged vessels that are enrolled in the U.S. Coast Guard’s Underwater Survey in Lieu of Dry-docking (“UWILD”) program are allowed to have their Intermediate Survey dry-docking requirement met with a less costly underwater inspection. Non-U.S. flagged vessels are required to meet applicable classification society rules and their own local standards for seaworthiness, which also mandate vessels to undergo . ​ The Company is responsible for maintaining its vessels in compliance with U.S. and international standards. As costs associated with dry-docking inspections provide future economic benefits to the Company through continued operation of the vessels, the costs are deferred and amortized until the scheduled date of the next required dry-docking, which is usually over a two period. Amortization of deferred dry-docking costs are charged to operating expenses of the Ocean Transportation segment in the Consolidated Statements of Income and Comprehensive Income. Routine vessel maintenance and repairs are charged to expense as incurred. ​ Goodwill and Intangible Assets: Goodwill and intangible assets arise as a result of acquisitions made by the Company (see Note 6). Intangible assets consist of customer relationships which are being amortized using the straight-line method over the expected useful lives ranging up to 21 years , and a trade name that has an indefinite life. ​ Impairment Evaluation of Long-Lived Assets, Intangible Assets and Goodwill : The Company evaluates its long-lived assets, intangible assets and goodwill for possible impairment in the fourth quarter, or whenever events or changes in circumstances indicate that it is more likely than not that the fair value is less than its carrying amount. The Company has reporting units within the Ocean Transportation and Logistics reportable segments. ​ Long-lived assets and finite-lived intangible assets are grouped at the lowest level reporting unit for which identifiable cash flows are available. In evaluating for impairment, the estimated future undiscounted cash flows generated by each of these asset groups are compared with the carrying value recorded for each asset group to determine if its carrying value is recoverable. If this review determines that the amount recorded will not be recovered, the amount recorded for the asset group is reduced to its estimated fair value. No impairment charges of long-lived assets and finite-lived intangible assets were recorded for the years ended December 31, 2020, 2019 and 2018. ​ Indefinite-life intangible assets and goodwill are grouped at the lowest level reporting unit for which identifiable cash flows are available. In estimating the fair value of a reporting unit, the Company uses a combination of a discounted cash flow model and fair value based on market multiples of earnings before interest, taxes, depreciation and amortization. Based upon the Company’s evaluation of its indefinite-life intangible assets and goodwill for impairment, the Company determined that the fair value of each reporting unit exceeds book value. No impairment charges of indefinite-life intangible assets and goodwill were recorded for the years ended December 31, 2020, 2019 and 2018. ​ Impairment Evaluation of SSAT: The Company’s investment in SSAT, a related party, is evaluated for impairment whenever there is evidence of impairment during the reporting period. If any impairment is identified, the Company evaluates if the decrease in the fair value of the investment below its carrying value is other-than-temporary. No impairment was identified during the years ended December 31, 2020, 2019 and 2018. ​ Other Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, Other Liabilities (in millions) 2020 2019 Payroll and vacation ​ $ 29.2 $ 28.5 ​ Employee incentives and other ​ ​ 25.9 ​ ​ 14.7 ​ Multi-employer withdrawal liabilities - short term (see Note 12) ​ ​ 10.6 ​ ​ 10.8 ​ Income tax liabilities ​ ​ 11.7 ​ ​ 2.3 ​ Insurance reserves and other related liabilities - short term ​ ​ 7.0 ​ ​ 12.6 ​ Deferred revenues ​ ​ 4.2 ​ ​ 6.9 ​ Interest on debt ​ ​ 3.4 ​ ​ 4.9 ​ Pension and post-retirement liabilities - short term (see Note 11) ​ ​ 2.7 ​ ​ 3.1 ​ Other short-term liabilities ​ ​ 2.1 ​ ​ 2.2 ​ Total ​ $ 96.8 $ 86.0 ​ ​ Other Long-Term Liabilities: Other long-term liabilities consist of the following at December 31, 2020 and 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, Other Long-Term Liabilities (in millions) 2020 2019 Pension and post-retirement liabilities (see Note 11) ​ $ 82.0 ​ $ 73.4 ​ Multi-employer withdrawal liability (see Note 12) ​ ​ 52.8 ​ ​ 54.8 ​ Insurance reserves and other related liabilities ​ ​ 25.4 ​ ​ 26.6 ​ Other long-term liabilities ​ 5.6 ​ 2.6 ​ Total ​ $ 165.8 ​ $ 157.4 ​ ​ Pension and Post-Retirement Plans: The Company is a member of the Pacific Maritime Association (“PMA”) and the Hawaii Stevedoring Industry Committee, which negotiate multi-employer pension plans covering certain shoreside bargaining unit personnel. The Company directly negotiates multi-employer pension plans covering other bargaining unit personnel. Pension costs are accrued in accordance with contribution rates established by the PMA, the parties to a plan or the trustees of a plan. Several trusteed, non-contributory, single-employer defined benefit plans and defined contribution plans cover substantially all other employees. ​ The estimation of the Company’s pension and post-retirement benefit expenses and liabilities requires that the Company make various assumptions. These assumptions include factors such as discount rates, expected long-term rates of return on pension plan assets, salary growth, health care cost trend rates, inflation, retirement rates, mortality rates, and expected contributions. Actual results that differ from the assumptions made could materially affect the Company’s financial condition or its future operating results. Additional information about the Company’s pension and post-retirement plans is included in Note 11. ​ Insurance Related Liabilities: The Company is uninsured for certain risks but when feasible, many of these risks are mitigated by insurance. The Company purchases insurance with deductibles or self-insured retentions. Such insurance includes, but is not limited to, employee health, workers’ compensation, marine liability, cybersecurity, auto liability and physical damage to property and equipment. For certain risks, the Company elects to not purchase insurance because of the excessive cost of insurance or the perceived remoteness of the risk. In addition, the Company retains all risk of loss that exceeds the limits of the Company’s insurance policies, or for other risks where insurance is not commercially available. ​ When estimating its reserves for retained risks and related liabilities, the Company considers a number of factors, including historical claims experience, demographic factors, current trends, and analyses provided by independent third-parties. Periodically, management reviews its assumptions and estimates used to determine the adequacy of the Company’s reserves for retained risks and other related liabilities. ​ Recognition of Revenues and Expenses: Revenue in the Company’s Consolidated Financial Statements is presented net of elimination of intercompany transactions. The following is a description of the Company’s principal revenue generating activities by segment, and the Company’s revenue recognition policy for each activity for the periods presented: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, Ocean Transportation (in millions) (1) ​ 2020 ​ 2019 ​ 2018 Ocean Transportation services ​ $ 1,821.7 ​ $ 1,625.8 ​ $ 1,599.3 Terminal and other related services ​ ​ 19.1 ​ ​ 24.8 ​ ​ 23.0 Fuel sales ​ ​ 7.3 ​ ​ 10.1 ​ ​ 12.2 Vessel management and related services ​ ​ 5.8 ​ ​ 5.9 ​ ​ 6.8 Total ​ $ 1,853.9 ​ $ 1,666.6 ​ $ 1,641.3 (1) Ocean Transportation revenue transactions are primarily denominated in U.S. dollars except for less than 3 percent of Ocean Transportation services revenue and fuel sales revenue categories which are denominated in foreign currencies. ​ ◾ Ocean Transportation services revenue is recognized ratably over the duration of a voyage based on the relative transit time completed in each reporting period. Vessel operating costs and other ocean transportation operating costs, such as terminal operating overhead and selling, general and administrative expenses, are charged to operating costs as incurred. ◾ Terminal and other related services revenue is recognized as the services are performed. Related costs are recognized as incurred. ◾ Fuel sales revenue and related costs are recognized when the Company has completed delivery of the product to the customer in accordance with the terms and conditions of the contract. ◾ Vessel management and related services revenue is recognized in proportion to the services completed. Related costs are recognized as incurred. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, Logistics (in millions) (1) ​ 2020 ​ 2019 (2) ​ 2018 (2) Transportation Brokerage and Freight Forwarding services ​ $ 477.0 ​ $ 489.0 ​ $ 532.5 Warehouse and distribution services ​ ​ 36.2 ​ ​ 34.1 ​ ​ 33.8 Supply chain management and other services ​ 16.2 ​ 13.4 ​ 15.2 Total ​ $ 529.4 ​ $ 536.5 ​ $ 581.5 (1) Logistics revenue transactions are primarily denominated in U.S. dollars except for approximately 3 percent of transportation brokerage and freight forwarding services revenue, and supply chain management and other services revenue categories which are denominated in foreign currencies. (2) The Company has reclassified $15.8 million and $16.6 million from transportation brokerage and freight forwarding services to warehouse and distribution services, and supply chain management and other services for the years ended December 31, 2019 and 2018 , respectively, to be consistent with its current period presentation. There was no change in total Logistics revenue for the years ended December 31, 2019 and 2018. ​ ◾ Transportation Brokerage and Freight Forwarding services revenue consists of amounts billed to customers for services provided. The primary costs include third-party purchased transportation services, agent commissions, labor and equipment. Revenue and the related purchased third-party transportation costs are recognized over the duration of a delivery based upon the relative transit time completed in each reporting period. Labor, agent commissions, and other operating costs are expensed as incurred. The Company reports revenue on a gross basis as the Company serves as the principal in these transactions because it is responsible for fulfilling the contractual arrangements with the customer and has latitude in establishing prices. ◾ Warehousing and distribution services revenue consist of amounts billed to customers for storage, handling, and value-added packaging of customer merchandise. Storage revenue is recognized in the month the service is provided to the customer. Storage related costs are recognized as incurred. Other warehousing and distribution services revenue and related costs are recognized in proportion to the services performed. ◾ Supply chain management and other services revenue, and related costs are recognized in proportion to the services performed. ​ The Company generally invoices its customers at the commencement of the voyage or the transportation service being provided, or as other services are being performed. Revenue is deferred when services are invoiced in advance to the customer. The Company’s receivables are classified as short-term as collection terms are for periods of less than one year. The Company expenses sales commissions and contract acquisition costs as incurred because the amounts are generally immaterial. These expenses are included in selling, general and administration expenses in the Consolidated Statements of Income and Comprehensive Income. ​ Customer Concentration: The Ocean Transportation segment serves customers in numerous industries and carries a wide variety of cargo, mitigating its dependence upon any single customer or single type of cargo. In 2020, 2019 and 2018, the percent of Ocean Transportation revenue, respectively. ​ The Logistics segment serves customers in numerous industries and geographical locations. In 2020, 2019 and 2018, the percent of Logistics revenue, respectively. ​ Dividends: ​ Share-Based Compensation: The Company records compensation expense for all share-based awards made to employees and directors. The Company’s various stock-based compensation plans are more fully described in Note 15. ​ Income Taxes: The estimate of the Company’s income tax expense requires the Company to make various estimates and judgments. These estimates and judgments are applied in the calculation of taxable income, tax credits, tax benefits and deductions, and in the calculation of certain deferred tax assets and liabilities, which arise from differences in the timing of recognition of revenue, costs and expenses for tax purposes. Deferred tax assets and liabilities are adjusted to the extent necessary to reflect tax rates expected to be in effect when the temporary differences reverse. ​ The Company records a valuation allowance if, based on the weight of available evidence, management believes that it is more likely than not that some portion or all of a recorded deferred tax asset would not be realized in future periods. The Company’s income taxes are more fully described in Note 10. ​ Rounding: Amounts in the Consolidated Financial Statements and Notes to the Consolidated Financial Statements are rounded to millions, except for per share calculations and percentages which were determined based on amounts before rounding. Accordingly, a recalculation of some per-share amounts and percentages, if based on the reported data, may be slightly different. ​ New Accounting Pronouncements : ​ Measurement of Credit Losses on Financial Instruments : In June 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016- 13 which amends the current approach to estimate credit losses on certain financial assets, including trade and other receivables, available-for-sale securities and other financial instruments. ASU 2016- 13 requires entities to establish a valuation allowance for the expected lifetime losses of certain financial instruments. Subsequent changes in the valuation allowance are recorded in current earnings and reversal of previous losses is permitted. The new standard was effective for interim and annual periods beginning on or after December 15, 2019. ​ The Company adopted ASU 2016- 13 effective January 1, 2020 using the modified retrospective approach. Upon adoption, the Company included an evaluation of expected future credit losses as part of its estimate for determining the allowance for doubtful accounts. The impact of this change was not material to the Company’s allowance for doubtful accounts receivable in the Consolidated Financial Statements. ​ Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract (“ASU 2018-15”): In August 2018, FASB issued ASU 2018-15 which aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing costs incurred to develop or obtain internal-use software. The Company adopted ASU 2018-15 on a prospective basis effective January 1, 2020. During the year ended December 31, 2020, the Company capitalized costs of $2.4 million related to cloud computing arrangements and which were included in other long-term assets on the Company’s Consolidated Balance Sheets as of December 31, 2020.

REPORTABLE SEGMENTS

REPORTABLE SEGMENTS	12 Months Ended
	Dec. 31, 2020
REPORTABLE SEGMENTS
REPORTABLE SEGMENTS	3. REPORTABLE SEGMENTS ​ Reportable segments are components of an enterprise that engage in business activities from which it may earn revenues and incur expenses, whose operating results are regularly reviewed by the chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and for which discrete financial information is available. The Company’s chief operating decision maker is its Chief Executive Officer. ​ The Company consists of two reportable segments, Ocean Transportation and Logistics, which are further described in Note 1. Reportable segments are measured based on operating income. In arrangements where the customer purchases ocean transportation and logistics services, the revenues are allocated to each reportable segment based upon the contractual amounts for each type of service. The Company’s SSAT segment has been aggregated into the Company’s Ocean Transportation segment due to the operations of SSAT being an integral part of the Company’s Ocean Transportation business (see Note 4). ​ The Company’s Ocean Transportation segment provides ocean transportation services to the Logistics segment, and the Logistics segment provides logistics services to the Ocean Transportation segment in certain transactions. Accordingly, inter-segment revenue of $115.5 million, $102.3 million and $95.4 million for the years ended December 31, 2020, 2019 and 2018, respectively, have been eliminated from operating revenues in the table below. ​ Reportable segment financial information for the years ended December 31, 2020, 2019 and 2018, and identifiable asset segment information at December 31, 2020 and 2019, are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, (In millions) 2020 2019 2018 Operating Revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ Ocean Transportation (1) ​ $ 1,853.9 ​ $ 1,666.6 ​ $ 1,641.3 Logistics (2) ​ 529.4 ​ 536.5 ​ 581.5 Total Operating Revenue ​ $ 2,383.3 ​ $ 2,203.1 ​ $ 2,222.8 Operating Income: ​ ​ ​ ​ ​ ​ ​ ​ ​ Ocean Transportation (3) ​ $ 244.8 ​ $ 90.8 ​ $ 131.1 Logistics ​ 35.5 ​ 38.3 ​ 32.7 Total Operating Income ​ 280.3 ​ 129.1 ​ 163.8 Interest expense, net ​ (27.4) ​ (22.5) ​ (18.7) Other income (expense), net ​ 6.1 ​ 1.2 ​ 2.6 Income before Income Taxes ​ 259.0 ​ 107.8 ​ 147.7 Income taxes ​ (65.9) ​ (25.1) ​ (38.7) Net Income ​ $ 193.1 ​ $ 82.7 ​ $ 109.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Capital Expenditures: ​ ​ ​ ​ ​ ​ ​ ​ ​ Ocean Transportation ​ $ 190.0 ​ $ 294.5 ​ $ 385.4 Logistics ​ 2.3 ​ 15.8 ​ 15.8 Total Capital Expenditures ​ $ 192.3 ​ $ 310.3 ​ $ 401.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Depreciation and Amortization: ​ ​ ​ ​ ​ ​ ​ ​ ​ Ocean Transportation ​ $ 107.4 ​ $ 93.6 ​ $ 87.0 Logistics ​ 7.5 ​ 6.8 ​ 7.4 ​ ​ ​ 114.9 ​ ​ 100.4 ​ ​ 94.4 Deferred dry-docking amortization - Ocean Transportation ​ ​ 25.1 ​ ​ 34.3 ​ ​ 37.4 Total Depreciation and Amortization ​ $ 140.0 ​ $ 134.7 ​ $ 131.8 (1) Ocean Transportation operating revenue excludes inter-segment revenue of $59.1 million, $52.8 million and $51.7 million for the years ended December 31, 2020, 2019 and 2018, respectively. (2) Logistics operating revenue excludes inter-segment revenue of $56.4 million, $49.5 million and $43.7 million for the years ended December 31, 2020, 2019 and 2018, respectively. (3) Ocean Transportation segment information includes $26.3 million, $20.8 million, and $36.8 million of equity in income from the Company’s equity investment in SSAT for the years ended December 31, 2020, 2019 and 2018, respectively. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, (In millions) 2020 2019 Identifiable Assets: ​ ​ ​ ​ ​ ​ Ocean Transportation (1) ​ $ 2,431.1 ​ $ 2,424.5 Logistics ​ 469.5 ​ 420.9 Total Assets ​ $ 2,900.6 ​ $ 2,845.4 (1) The Ocean Transportation segment includes $48.7 million and $76.2 million related to the Company’s equity investment in SSAT as of December 31, 2020 and 2019, respectively.

INVESTMENT IN SSAT

INVESTMENT IN SSAT	12 Months Ended
	Dec. 31, 2020
INVESTMENT IN SSAT
INVESTMENT IN SSAT	4. INVESTMENT IN SSAT ​ The Company accounts for its 35 percent ownership interest in SSAT using the equity method of accounting. The Company records its share of income from SSAT in costs and expenses within the Ocean Transportation segment due to operations of SSAT being an integral part of the Company’s Ocean Transportation business. The Company’s investment in SSAT was $48.7 million and $76.2 million at December 31, 2020 and 2019, respectively. During the year ended December 31, 2020, the Company recorded an increase of $2.2 million in its investment in SSAT and a corresponding increase in retained earnings related to the formation of a new subsidiary of SSAT, whose controlling interest is retained by SSAT. ​ The Company’s share of income recorded in the Consolidated Statements of Income and Comprehensive Income and dividends received by the Company during the years ended December 31, 2020, 2019 and 2018 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, (In millions) 2020 2019 2018 Company's share of net income ​ $ 26.3 ​ $ 20.8 ​ $ 36.8 ​ Distributions received ​ $ 55.4 ​ $ 25.2 ​ $ 42.0 ​ ​ The Company’s Ocean Transportation segment operating costs include $251.6 million, $218.7 million and $213.4 million for the years ended December 31, 2020, 2019 and 2018, respectively, for terminal services provided by SSAT. Accounts payable and accrued liabilities in the Consolidated Balance Sheets include $29.8 million and $63.6 million for terminal services payable to SSAT at December 31, 2020 and 2019, respectively. ​ A summary of the condensed balance sheets of SSAT at December 31, 2020 and 2019 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ Condensed Balance Sheets (in millions) 2020 2019 Current assets ​ $ 294.3 ​ $ 300.8 ​ Non-current assets ​ 1,249.5 ​ 1,283.0 ​ Total Assets ​ $ 1,543.8 ​ $ 1,583.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ Current liabilities ​ $ 238.2 ​ $ 201.9 ​ Non-current liabilities ​ 1,179.9 ​ 1,179.2 ​ Equity ​ 125.7 ​ 202.7 ​ Total Liabilities and Equity ​ $ 1,543.8 ​ $ 1,583.8 ​ ​ A summary of the condensed statements of operating income and net income of SSAT for years ended December 31, 2020, 2019 and 2018 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ Condensed Statements of Operating Income and Net Income (in millions) 2020 2019 2018 Operating revenue ​ $ 1,091.6 ​ $ 1,098.3 ​ $ 1,074.2 ​ Operating costs and expenses ​ 1,003.2 ​ 1,035.3 ​ 963.7 ​ Operating income ​ 88.4 ​ 63.0 ​ 110.5 ​ Net Income (1) ​ $ 76.6 ​ $ 57.2 ​ $ 104.9 ​ (1) Includes earnings from equity method investments held by SSAT less earnings allocated to non-controlling interests.

PROPERTY AND EQUIPMENT

PROPERTY AND EQUIPMENT	12 Months Ended
	Dec. 31, 2020
PROPERTY AND EQUIPMENT
PROPERTY AND EQUIPMENT	5. PROPERTY AND EQUIPMENT ​ Property and equipment at December 31, 2020 and 2019, and depreciation expense for the years ended December 31, 2020, 2019 and 2018 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2020 ​ As of December 31, 2019 ​ ​ ​ Accumulated ​ ​ ​ Accumulated ​ (In millions) ​ Cost ​ Depreciation ​ Net Book Value ​ Cost ​ Depreciation ​ Net Book Value Vessels ​ $ 2,191.6 ​ $ 785.5 ​ $ 1,406.1 ​ ​ $ 1,653.5 ​ $ 818.5 ​ $ 835.0 ​ Containers and equipment ​ 572.3 ​ ​ 391.8 ​ 180.5 ​ ​ 544.5 ​ 378.8 ​ 165.7 ​ Terminal facilities and other property ​ 119.8 ​ ​ 45.1 ​ 74.7 ​ ​ 114.4 ​ 41.3 ​ 73.1 ​ Vessel construction in progress ​ ​ — ​ ​ — ​ ​ — ​ ​ ​ 488.9 ​ ​ — ​ ​ 488.9 ​ Other construction in progress ​ 28.6 ​ ​ — ​ 28.6 ​ ​ 35.4 ​ — ​ 35.4 ​ Total ​ $ 2,912.3 ​ $ 1,222.4 ​ $ 1,689.9 ​ ​ $ 2,836.7 ​ $ 1,238.6 ​ $ 1,598.1 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, (In millions) 2020 2019 2018 Depreciation expense ​ $ 97.1 ​ $ 86.3 ​ $ 80.5 ​ ​

GOODWILL AND INTANGIBLES ASSETS

GOODWILL AND INTANGIBLES ASSETS	12 Months Ended
	Dec. 31, 2020
GOODWILL AND INTANGIBLES ASSETS
GOODWILL AND INTANGIBLES ASSETS	6. GOODWILL AND INTANGIBLE ASSETS ​ Goodwill by segment as of December 31, 2020 and 2019 consists of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ocean ​ ​ ​ ​ ​ ​ (In millions) Transportation Logistics Total Goodwill ​ $ 222.6 ​ $ 105.2 ​ $ 327.8 ​ Logistics goodwill of $105.2 million includes $78.6 million acquired as part of the acquisition of Span Intermediate, LLC (“Span Alaska”) in August 2016 that was allocated to the Span Alaska reporting unit, and $26.6 million relates to other Logistics acquisitions that were allocated to the Logistics reporting unit. ​ Intangible assets by segment as of December 31, 2020 and 2019 consist of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2020 ​ As of December 31, 2019 ​ ​ Gross ​ Accumulated ​ ​ ​ ​ Gross ​ Accumulated ​ ​ ​ (In millions) Amount Amortization Net Book Value Amount Amortization Net Book Value Ocean Transportation - Customer relationships ​ $ 140.6 ​ $ 37.9 ​ $ 102.7 ​ ​ $ 140.6 ​ $ 31.2 ​ $ 109.4 ​ Logistics: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Customer relationships ​ ​ 90.1 ​ ​ 28.1 ​ ​ 62.0 ​ ​ ​ 90.1 ​ ​ 23.9 ​ ​ 66.2 ​ Trade name ​ 27.3 ​ ​ — ​ ​ 27.3 ​ ​ 27.3 ​ ​ — ​ ​ 27.3 ​ Total Logistics ​ 117.4 ​ ​ 28.1 ​ ​ 89.3 ​ ​ 117.4 ​ ​ 23.9 ​ ​ 93.5 ​ Total ​ $ 258.0 ​ $ 66.0 ​ $ 192.0 ​ ​ $ 258.0 ​ $ 55.1 ​ $ 202.9 ​ ​ Ocean Transportation intangible assets of $140.6 million relate to customer relationships acquired as part of the acquisition of Horizon Lines, Inc. (“Horizon”) on May 29, 2015, and are being amortized over 21 years . Logistics intangible assets include $79.3 million of customer relationships which are being amortized over 20 years , and $27.3 million of an indefinite life trade name, both acquired as part of the Span Alaska acquisition. The remaining Logistics customer relationships of $10.8 million are being amortized over a period of up to 13 years . ​ Intangible assets related amortization expense for 2020, 2019 and 2018, is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, (In millions) 2020 2019 2018 Amortization expense ​ $ 10.9 ​ $ 11.1 ​ $ 11.2 ​ ​ As of December 31, 2020, estimated amortization expense related to customer relationship intangible assets during the next five years and thereafter is as follows: ​ ​ ​ ​ ​ ​ ​ Customer ​ Year (in millions) ​ Relationships 2021 ​ $ 10.9 ​ 2022 ​ 10.7 ​ 2023 ​ 10.7 ​ 2024 ​ 10.7 ​ 2025 ​ 10.7 ​ Thereafter ​ 111.0 ​ Total ​ $ 164.7 ​ ​

CAPITAL CONSTRUCTION FUND

CAPITAL CONSTRUCTION FUND	12 Months Ended
	Dec. 31, 2020
CAPITAL CONSTRUCTION FUND.
CAPITAL CONSTRUCTION FUND	7. CAPITAL CONSTRUCTION FUND ​ The Company is party to an agreement with the U.S. Department of Transportation, Maritime Administration (“MARAD”) that established a Capital Construction Fund (“CCF”) program under provisions of the Merchant Marine Act of 1936, as amended (the “Merchant Marine Act”). The CCF program was created to assist owners and operators of U.S. flagged vessels in raising capital necessary for the modernization and expansion of the U.S. merchant marine fleet. CCF funds may be used for the acquisition, construction, or reconstruction of vessels, and for repayment of existing vessel indebtedness through the deferment of federal income taxes on certain deposits of monies and other property placed into the CCF. Qualified withdrawals from the CCF must be used for investment in vessels built in the U.S. and used between covered U.S. ports as described by the Merchant Marine Act, and for other qualifying expenditures (see Item 1 of Part 1 for additional information on Maritime Laws and the Jones Act). Participants of the CCF must also meet certain U.S. citizenship requirements. ​ Deposits into the CCF are limited by certain applicable earnings and other conditions. Such deposits, once made, are available as tax deductions in the Company’s income tax provision. Qualified withdrawals from the CCF do not give rise to a current income tax liability, but reduce the depreciable basis of the vessels or certain related equipment for income tax purposes. However, if withdrawals are made from the CCF for general corporate purposes or other non-qualified purposes, or upon termination of the agreement, they are taxable with interest payable from the year of deposit. ​ Deposits not committed for qualified purposes within 25 years from the date of deposit will be treated as non-qualified withdrawals over the subsequent five years . Under the terms of the CCF agreement, the Company may designate certain qualified earnings as “accrued deposits” or may designate, as obligations of the CCF, qualified withdrawals to reimburse qualified expenditures initially made with operating funds. Such accrued deposits to, and withdrawals from, the CCF are reflected in the Consolidated Balance Sheets either as obligations of the Company’s current assets or as receivables from the CCF. ​ As of December 31, 2020 and 2019, $1.7 million of eligible accounts receivable were assigned to the CCF. Due to the nature of the assignment of eligible accounts receivable into the CCF, such assigned amounts are classified as part of accounts receivable in the Consolidated Balance Sheets. At December 31, 2020 and 2019, the amounts on deposit in the CCF invested in a money market fund, which is classified as other long-term assets in the Company’s Consolidated Balance Sheets, were nominal.

DEBT

DEBT	12 Months Ended
	Dec. 31, 2020
DEBT
DEBT	8. DEBT ​ At December 31, 2020 and 2019, the Company’s debt consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ (In millions) 2020 2019 Private Placement Term Loans: ​ ​ ​ ​ ​ ​ ​ 5.79 %, payable through 2020 ​ $ — ​ $ 3.5 ​ 3.66 %, payable through 2023 ​ 22.8 ​ 31.9 ​ 4.16 %, payable through 2027 ​ 34.0 ​ 39.3 ​ 3.37 %, payable through 2027 ​ ​ 75.0 ​ ​ 75.0 ​ 3.14 %, payable through 2031 ​ ​ 169.6 ​ ​ 188.0 ​ 4.31 %, payable through 2032 ​ 27.9 ​ 30.3 ​ 4.35 %, payable through 2044 ​ ​ — ​ ​ 100.0 ​ 3.92 %, payable through 2045 ​ ​ — ​ ​ 69.5 ​ Title XI Debt: ​ ​ ​ ​ ​ ​ ​ 5.34 %, payable through 2028 ​ 17.6 ​ 19.8 ​ 5.27 %, payable through 2029 ​ 19.8 ​ 22.0 ​ 1.22 %, payable through 2043 ​ ​ 182.0 ​ ​ — ​ 1.35 %, payable through 2044 ​ ​ 139.6 ​ ​ — ​ Revolving credit facility, maturity date of June 29, 2022 ​ 71.8 ​ 379.1 ​ Total Debt ​ 760.1 ​ 958.4 ​ Less: Current portion ​ (59.2) ​ (48.4) ​ Total Long-term Debt ​ ​ 700.9 ​ ​ 910.0 ​ Less: Deferred loan fees ​ ​ (15.3) ​ ​ — ​ Total Long-term Debt, net of deferred loan fees ​ $ 685.6 ​ $ 910.0 ​ ​ The following is a description of the Company’s debt: ​ Private Placement Term Loans : The million plus interest. These notes were fully paid off during the year ended December 31, 2020. ​ During the second quarter of 2012, the Company issued $170.0 million of unsecured notes, which funded in three tranches, $77.5 million at an interest rate of 3.66 percent, $55.0 million at an interest rate of 4.16 percent, and $37.5 million at an interest rate of 4.31 percent (the “2012 Notes”). Principal and interest are payable semi-annually. The 2012 Notes began to amortize in 2015 with aggregate semi-annual payments of $4.6 million which continued through 2016, followed by $8.4 million in 2017 through mid-year 2023, $3.8 million through mid-year 2027, and $1.2 million thereafter. ​ In January 2014, the Company issued $100.0 million of 30 -year senior unsecured notes at an interest rate of 4.35 percent, payable semi-annually. These notes were fully paid off during the year ended December 31, 2020. ​ In July 2015, the Company issued $75.0 million of 30 -year senior unsecured notes at an interest rate of 3.92 percent, payable semi-annually. These notes were fully paid off during the year ended December 31, 2020. ​ In September 2016, the Company issued $200.0 million of 15-year senior unsecured notes (the “Series D Notes”) at an interest rate of 3.14 percent, payable semi-annually. The Series D Notes began to amortize in 2019, with semi-annual principal payments of million. During the years 2020 through 2023, semi-annual principal payments will be million. Starting in 2024, and in each year thereafter through maturity in 2031, the semi-annual principal payments will be ​ In December 2016, the Company issued $75 million of 11-year senior unsecured notes at an interest rate of 3.37 percent, payable semi-annually (the “Series A Notes”). The Series A Notes will begin to amortize in 2021, with principal payments of ​ Existing and 2020 Title XI Bonds: In September 2003, MatNav issued Manukai (the “Manukai Title XI Bonds”). The Manukai Title XI Bonds have a final maturity in September 2028 with a coupon rate of percent. The Manukai Title XI Bonds are amortized by semi-annual payments of million plus interest. In August 2004, MatNav issued Maunawili (the “Maunawili Title XI Bonds”, and together with the Manukai Title XI Bonds, the “Existing Title XI Bonds”). The Maunawili Title XI Bonds have a final maturity in July 2029 with a coupon rate of percent. The Maunawili Title XI Bonds are amortized by semi-annual payments of ​ On April 27, 2020, MatNav issued $185.9 million in U.S. Government guaranteed vessel financing bonds to partially refinance debt incurred in connection with the construction of Daniel K. Inouye (the “DKI Title XI Debt”). A fee of approximately million was paid to MARAD out of the proceeds at closing. The secured DKI Title XI Debt matures on October 15, 2043 and has a cash interest rate of million. ​ On June 22, 2020, MatNav issued $139.6 million in U.S. Government guaranteed vessel financing bonds to partially refinance debt incurred in connection with the construction of Kaimana Hila (the “KMH Title XI Debt”, and together with the DKI Title XI Debt, the “2020 Title XI Debt”). A fee of approximately million was paid to MARAD out of the proceeds at closing. The secured KMH Title XI Debt matures on March 15, 2044 and has a cash interest rate of million. ​ MatNav may prepay any amounts outstanding under the 2020 Title XI Debt agreements subject to a potential prepayment premium or other adjustment, in accordance with the 2020 Title XI Debt agreements. Once amounts under the 2020 Title XI Debt are repaid, they may not be reborrowed. Mandatory prepayments are required under certain limited circumstances, including specified casualty events with respect to the vessels Daniel K. Inouye Kaimana Hila (the “Vessels”). ​ Revolving Credit Facility: On June 29, 2017, the Company entered into an amended and restated credit agreement that provides the Company with additional sources of liquidity for working capital, capital expenditures and investment opportunities, and amends and restates the Company’s previously amended and restated credit agreement (the “Credit Agreement” or the “revolving credit facility”). The Credit Agreement expires on June 29, 2022, and provides for committed aggregate borrowing of up to million. The aggregate borrowing within the Credit Agreement includes a million sublimit for swing line loans. The Company may prepay any amounts outstanding under the Credit Agreement without premium or penalty. All obligations of the Company under the Credit Agreement are guaranteed by MatNav and certain other subsidiaries. ​ On March 31, 2020, the Company entered into a First Amendment to Amended and Restated Credit Agreement (the “Credit Agreement Amendment”). The Credit Agreement Amendment provides for amendments to certain covenants and other terms, including increasing the permitted consolidated leverage ratio from March 31, 2020 to December 30, 2021, amending the pricing grid to provide for pricing ranging from, at the Company’s election, LIBOR plus a margin between 21, 2027. In addition, the Credit Agreement Amendment adds a “most favored lender” provision for the benefit of the lenders with respect to the Company’s Private Debt Agreements (as defined below). Pursuant to the Credit Agreement Amendment, commencing March 31, 2020, borrowings under the Credit Agreement bear interest at either LIBOR plus a margin of between percent. Letters of credit are subject to fees based on the Company’s consolidated net leverage ratio at a rate of between percent depending on the Company’s consolidated net leverage ratio. ​ As of December 31, 2020, the Company had $570.1 million of remaining borrowing availability under the revolving credit facility. The Company had 31, 2020. Based on the Company’s consolidated net leverage ratio, which stipulates borrowing margins, the interest rate applicable to revolving credit facility was approximately 2.50 percent at December 31, 2020. ​ Amendments to Existing Private Placement Term Loan Facilities and New Shelf Facilities (“Private Loan Facilities”): On June 29, 2017, the Company and the holders of the Company’s term loans entered into amendments (collectively, the “2017 Amendments”) to each of Company’s Private Loan Facilities. The 2017 Amendments provide for amendments to certain covenants and other terms, including (at the Company’s option under certain circumstances) adjustments to the required consolidated leverage ratio, and, in connection with the exercise of such option, the payment of additional interest for certain pre-defined periods. ​ On March 31, 2020, the Company and the holders of notes party thereto entered into amendments (collectively, the “2020 Amendments”) to each of the Company’s Private Loan Facilities. The 2020 Amendments modify certain covenants and other terms, including increasing the permitted consolidated leverage ratio from March 31, 2020 to December 30, 2021; providing for additional quarterly interest enhancement payments based on the Company’s consolidated leverage ratio from the quarter ended March 31, 2020 through the quarters ending December 31, 2021; providing for an additional 30, 2021 and September 30, 2021; providing for prepayment at par at the option of the holders with proceeds of certain 2020 Title XI Debt and dispositions of capital assets; providing for additional limitations on stock redemptions and repurchases, sale leaseback transactions and asset sales during the period from March 31, 2020 through and including December 30, 2021; and providing for additional limitations on incurrence of priority debt through December 21, 2027. In addition, the 2020 Amendments add a “most favored lender” provision for the benefit of the noteholders with respect to the other Private Debt Agreements. ​ Debt Maturities: At December 31, 2020, debt maturities during the next five years and thereafter are as follows: ​ ​ ​ ​ ​ ​ ​ As of Year (in millions) December 31, 2020 2021 ​ $ 59.2 2022 ​ 136.8 2023 ​ 60.4 2024 ​ 51.7 2025 ​ 51.7 Thereafter ​ 400.3 Total Debt ​ $ 760.1 ​ Deferred Loan Fees: Activity relating to deferred loan fees for the year ended December 31, 2020 are as follows: ​ ​ ​ ​ ​ Deferred Loan Fees (in millions) Amount Deferred financing costs related to Title XI bonds and private placement debt amendments ​ $ 16.5 Deferred fees expensed related to the redemption of private placement debt ​ ​ (0.3) Amortization expense for the year ended December 31, 2020 ​ (0.9) Balance at December 31, 2020 ​ $ 15.3 ​ As of December 31, 2020, amortization expense relating to deferred loan fees during the next five years and thereafter are as follows: ​ ​ ​ ​ ​ Year (in millions) Amount 2021 ​ $ 1.5 2022 ​ 1.2 2023 ​ 1.1 2024 ​ 1.1 2025 ​ 1.0 Thereafter ​ 9.4 Total amortization expense of deferred loan fees ​ $ 15.3 ​ Debt Covenants in the Private Placement Term Loans and the Revolving Credit Facility : The Credit Agreement and Private term loan facilities (collectively, the “Private Debt Agreements”) contain affirmative, negative and financial covenants customary for financings of this type, including, among other things, limitations on certain other indebtedness, loans and investments, liens, mergers, asset sales, and transactions with affiliates as defined within the Private Debt Agreements. The Private Debt Agreements also contain customary events of default, including cross defaults to other material indebtedness, including the Existing Title XI Bonds and the 2020 Title XI Debt. A brief description of the principal covenants contained in the Private Debt Agreements includes, but is not limited to the following (as defined within the Private Debt Agreements): ​ ◾ Minimum Consolidated Interest Coverage Ratio as of the end of any fiscal quarter is not permitted to be less than 3.50 to 1.0; ◾ Maximum Consolidated Leverage Ratio as of the end of any fiscal quarter is not permitted to exceed the ratios specified in the Private Debt Agreements for the applicable quarter; and ◾ No Priority Debt may be incurred other than: (i) an aggregate of $331,000,000 principal amount of Title XI Priority Debt and (ii) Priority Debt incurred by Foreign Subsidiaries in an aggregate principal amount not to exceed $20,000,000 . ​ Principal covenants generally will restrict the incurrence of liens except for permitted liens, which include, without limitation, liens securing Title XI debt up to certain permitted amounts, as defined within the Private Debt Agreements. The Company was in compliance with these covenants as of December 31, 2020. ​ Debt Covenants in Existing Title XI Bonds and 2020 Title XI Debt Agreements: The Existing Title XI Bonds contain customary representations and warranties as well as affirmative and negative covenants, defaults and other provisions typical for MARAD-guaranteed financings of this type, with definitions and limitations as defined within the Existing Title XI Bonds. These covenants include, among other things, minimum working capital and net worth requirements, limitations on certain other indebtedness, loans and investments, liens, mergers, asset sales, sale and leaseback transactions, and transactions with affiliates as defined within the Existing Title XI Bonds. Certain of the covenants in the Existing Title XI Bonds are applicable only upon and during the continuance of either (i) an event of default or (ii) the failure of MatNav to meet certain financial requirements. ​ The 2020 Title XI Debt agreements contain customary representations and warranties as well as affirmative and negative covenants, defaults and other provisions typical for MARAD-guaranteed financings of this type, with definitions, limitations and financial tests all as negotiated between MatNav and MARAD. As part of the 2020 Title XI Debt agreements, certain covenants contained in the Existing Title XI Bonds were eliminated. The covenants in the 2020 Title XI Debt agreements include, among other things, limitations on certain other indebtedness, loans and investments, liens, mergers, asset sales, sale-leasebacks, and transactions with affiliates as defined within the 2020 Title XI Debt agreements. Certain of the covenants in the 2020 Title XI Debt agreements are applicable only upon and during the continuance of either (i) an event of default or (ii) the failure of either the Company or MatNav to meet certain supplemental financial tests. ​ ● The supplemental financial tests applicable to MatNav include maintenance of a working capital minimum of $1 , and maintenance of a long term debt to net worth ratio of greater than or equal to 2.0 to 1.0; and ● The supplemental financial tests applicable to the Company include maintenance of a net worth greater than or equal to 90% of the net worth of the Company as set forth in the most recent audited financial statements prior to closing of the issuance of the 2020 Title XI Bonds and compliance with the leverage ratio set forth in the Company’s Credit Agreement. ​ Debt Security and Guarantees: ​ Under the 2020 Title XI Debt agreements, MARAD has guaranteed certain obligations of MatNav. MatNav has agreed to reimburse MARAD for any payments it makes under the MARAD guaranty, and MatNav’s obligations to MARAD with respect to the 2020 Title XI Debt are secured by a mortgage on the Vessels and certain other related assets (the “Collateral”), as well as the Existing Vessels (as defined below). In addition, MatNav’s obligations to MARAD with respect to the 2020 Title XI Debt are guaranteed by the Company under an Affiliate Guaranty (the “Guaranty”). ​ The 2020 Title XI Debt agreements also provide that the two vessels securing MatNav’s Existing Title XI Bonds – Manukai Maunawili

LEASES

LEASES	12 Months Ended
	Dec. 31, 2020
LEASES
LEASES	9. LEASES ​ The Company adopted the lease accounting standard ASC 842 on January 1, 2019. As part of the adoption, the Company recorded a net adjustment to retained earnings of $4.4 million at January 1, 2019. Significant assumptions and judgments made in applying the new lease accounting standard include determining the Company’s incremental borrowing rate and evaluating the probability of exercising lease options. ​ Description of Operating Leases: The Company has different types of operating leases, the specific terms and conditions of which vary from lease to lease. Certain operating lease agreements include terms such as: (i) renewal and early termination options; (ii) early buy-out and purchase options; and (iii) rent escalation clauses. The lease agreements also include provisions for the maintenance of the leased asset and payment of lease related costs. The Company reviews the specific terms and conditions of each lease and, as appropriate, notifies the lessor of any intent to exercise any option in accordance with the terms of the lease. In the normal course of business, the Company expects to be able to renew or replace most of its operating leases with other similar leases as they expire. Except for the residual value guarantee described below, the Company’s leases do not contain any other residual value guarantees. ​ The Company’s sub-lease income was nominal to the Company’s Consolidated Statements of Income and Comprehensive Income for the years ended December 31, 2020 and 2019. The Company did not have any finance leases during the years ended December 31, 2020 and 2019. Certain of the Company’s lease agreements include rental payments that may be adjusted in the future based on economic conditions and others include rental payments adjusted periodically for inflation. Variable lease expense is disclosed for the adjusted portion of such payments. ​ The lease type by underlying asset class and maximum terms of the Company’s operating leases are as follows: ​ ​ ​ ​ Lease Type: Term Real estate and terminal leases 65 years Vessel charter leases 10 years Operations equipment and other leases 8 years ​ Incremental Borrowing Rate: As most of the Company’s operating leases do not provide an implicit rate, the Company uses an estimated incremental borrowing rate based on information available at the date of adoption and subsequent lease commencement dates in calculating the present value of its operating lease liabilities. The incremental borrowing rate is determined using the U.S. Treasury rate adjusted to account for the Company’s credit rating and the collateralized nature of operating leases. ​ Components of Lease Cost: Components of lease cost recorded in the Company’s Consolidated Statement of Income and Comprehensive Income for the years ended December 31, 2020 and 2019 consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended ​ ​ December 31, (In millions) 2020 ​ 2019 Operating lease cost ​ $ 83.1 ​ $ 71.4 Short-term lease cost ​ 10.6 ​ 5.9 Variable lease cost ​ 0.8 ​ 0.4 Total lease cost ​ $ 94.5 ​ $ 77.7 ​ Other Lease Information: Other information related to the Company’s operating leases for the years ended December 31, 2020 and 2019 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended ​ ​ December 31, (In millions) 2020 ​ 2019 Cash paid for amounts included in operating lease liabilities ​ $ 83.6 ​ $ 71.3 Right of use assets obtained in the exchange for new operating lease liabilities ​ $ 70.1 ​ $ 65.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2020 2019 Weighted average remaining operating lease term ​ ​ 7.0 years ​ ​ 7.5 years Weighted average incremental borrowing rate ​ ​ 3.7% ​ ​ 4.2% ​ Maturities of operating lease liabilities at December 31, 2020 are as follows: ​ ​ ​ ​ ​ ​ As of Year (in millions) December 31, 2020 2021 ​ $ 80.5 2022 ​ 53.2 2023 ​ 47.3 2024 ​ 31.8 2025 ​ 23.9 Thereafter ​ 65.6 Total lease payments ​ ​ 302.3 Less: Interest ​ ​ (43.0) Present value of operating lease liabilities ​ ​ 259.3 Less: Short-term portion ​ ​ (72.4) Long-term operating lease liabilities ​ $ 186.9 ​ Sale and Leaseback of Equipment: On March 25, 2020, the Company entered into an agreement for the sale and leaseback of multiple tranches of chassis and container equipment. The net proceeds from the sales were ​ Vessel Charter and Buyer-Lessor Guaranty ​ Vessel Charter: Maunalei million and subsequently leased back from the buyer-lessor under a Bareboat Charter Agreement (the “Charter”). The transaction qualified for sale and leaseback treatment under ASC 840, Leases , with the Charter treated as an operating lease for accounting purposes. Lease payments are approximately $3.0 million per quarter, and the base term of the Charter is five years with a two year end-of-term renewal option . Total future minimum lease payments were $36.0 million at December 31, 2020, and the obligations under the lease are included in the maturities of operating lease liabilities table above. ​ Prior to the expiration of the base term of the Charter, the subsidiary may, at its option, elect to: (i) purchase the vessel at the option price; (ii) exercise the option to renew the Charter for an additional two years; or (iii) remarket the vessel to sell to a third-party on behalf of the buyer-lessor. The purchase option price is $68.9 million after the base term and $58.3 million after the extended term. The Charter also includes a maximum residual value guarantee amount of $50.9 million after five years, or $47.7 million after the extended term. Proceeds from the sale of the vessel reduces the subsidiary’s residual value guarantee. ​ Buyer-Lessor Guaranty:

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2020
INCOME TAXES
INCOME TAXES	10. INCOME TAXES ​ Income Taxes: percent. The rate reduction and other changes took effect on January 1, 2018. Other changes such as remeasurement of deferred tax assets and liabilities were effective as of the fourth quarter of 2017. ​ Income taxes for the years ended December 31, 2020, 2019 and 2018 consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, (In millions) 2020 2019 2018 Current: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Federal ​ $ — ​ $ 0.2 ​ $ 1.5 ​ State ​ 8.7 ​ 3.2 ​ 2.1 ​ Foreign ​ ​ 1.4 ​ ​ 1.3 ​ ​ 0.9 ​ Discrete adjustments related to the Tax Act (1) ​ ​ — ​ ​ (2.9) ​ ​ 2.9 ​ Total ​ 10.1 ​ 1.8 ​ 7.4 ​ Deferred: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferred tax expense ​ ​ 55.8 ​ ​ 23.3 ​ ​ 31.3 ​ Total income taxes ​ $ 65.9 ​ $ 25.1 ​ $ 38.7 ​ (1) Current income taxes for the years ended December 31, 2019 and 2018 include a non-cash income tax benefit of $2.9 million and a non-cash income tax expense of $2.9 million, respectively, which relates to discrete adjustments as a result of applying the provisions of the Tax Act. ​ Income taxes for the years ended December 31, 2020, 2019 and 2018 differ from amounts computed by applying the statutory federal rate to income before income taxes for the following reasons: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ 2020 2019 2018 Computed federal income tax expense 21.0 % 21.0 % 21.0 % State income tax 3.5 % 4.1 % 3.4 % Valuation allowance (0.2) % (0.3) % (0.7) % Foreign taxes 0.6 % 1.2 % 0.6 % Remeasurement and discrete adjustments related to the Tax Act (1) — % (2.7) % 2.0 % Share-based payments (0.5) % (0.1) % 0.1 % Other — net 1.0 % 0.1 % (0.2) % Effective income tax rate 25.4 % 23.3 % 26.2 % (1) Effective income tax rate for the years ended December 31, 2019 and 2018 includes the impact of a non-cash income tax benefit of $2.9 million, or 2.7 percent, and a non-cash income tax expense of $2.9 million, or 2.0 percent, respectively, which related to certain discrete adjustments as a result of applying the provisions of the Tax Act. ​ The tax effects of temporary differences that gave rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, 2020 and 2019, were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, (In millions) 2020 2019 Deferred tax assets: ​ ​ ​ ​ ​ ​ ​ Operating lease liabilities ​ $ 63.5 ​ $ 63.1 ​ Pension and post-retirement plans ​ ​ 21.7 ​ ​ 19.2 ​ Multi-employer withdrawal liabilities ​ ​ 15.6 ​ ​ 16.1 ​ Federal net operating losses ​ ​ 0.9 ​ ​ 14.3 ​ State net operating losses ​ ​ 7.5 ​ ​ 7.3 ​ U.S. State alternative minimum tax credits ​ 4.4 ​ 6.7 ​ Insurance reserves ​ 5.3 ​ 5.9 ​ Deferred compensation ​ 8.2 ​ ​ 5.8 ​ Other ​ 10.4 ​ 5.9 ​ Total deferred tax assets ​ 137.5 ​ 144.3 ​ Valuation allowance ​ ​ (10.0) ​ ​ (10.6) ​ Total deferred tax assets, net of valuation allowance ​ ​ 127.5 ​ ​ 133.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferred tax liabilities: ​ ​ ​ ​ ​ ​ ​ Basis differences for property and equipment ​ 372.4 ​ 319.2 ​ Operating lease right of use assets ​ 61.5 ​ 61.1 ​ Intangibles ​ ​ 40.5 ​ ​ 39.7 ​ Lease financing ​ ​ 22.0 ​ ​ 23.7 ​ Capital Construction Fund ​ 6.7 ​ ​ 12.5 ​ Investment in SSAT ​ 7.4 ​ 7.4 ​ Other ​ ​ 6.6 ​ ​ 7.7 ​ Total deferred tax liabilities ​ 517.1 ​ 471.3 ​ Deferred tax liability, net ​ $ 389.6 ​ $ 337.6 ​ ​ Valuation Allowance: million as of December 31, 2020 and 2019, respectively. The Company believes that it is more likely than not that the benefit from these amounts will not be realized. The Company recorded a decrease (increase) to its valuation allowance of $0.6 million, $0.9 million and ($1.1) million during the years ended December 31, 2020, 2019 and 2018, respectively. ​ Net Operating Losses and Tax Credit Carryforwards: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (In millions) ​ Expiration Date 2020 2019 U.S. Federal income tax NOLs ​ Various dates beginning in 2027 ​ $ 7.6 ​ $ 71.2 U.S. State income tax NOLs (1) ​ Various dates beginning in 2032 ​ $ 185.9 ​ $ 184.5 U.S. State alternative minimum tax credit ​ No expiration date ​ $ 4.0 ​ $ 6.7 Foreign income tax NOLs ​ No expiration date ​ $ 11.9 ​ $ 14.0 (1) The Company does not expect to benefit from $157.9 million and $157.9 million of U.S. State income tax NOLs as of December 31, 2020 and 2019, respectively. ​ The U.S. federal and state income tax NOLs in the Company’s filed income tax returns include unrecognized tax benefits. The deferred tax assets recognized for those NOLs are presented net of these unrecognized tax benefits. As a result of changes in tax legislation, the use of a portion of the Company’s domestic NOL and tax credit carryforwards may be limited in future periods. Further, a portion of the federal and state income tax NOLs and tax credit carryforwards may expire before being applied to reduce future income tax liabilities. ​ Unrecognized Tax Benefits: Total unrecognized benefits represent the amount that, if recognized, would favorably affect the Company’s incomes taxes and effective tax rate in future periods. The Company does not expect a material change in gross unrecognized benefits in the next twelve months. A reconciliation of the beginning and ending amount of gross unrecognized tax benefits is as follows: ​ ​ ​ ​ ​ ​ Unrecognized Tax Benefits (in millions) Amount Balance at December 31, 2017 ​ $ 15.9 ​ Changes in tax positions of prior years, net ​ (0.3) ​ Reductions for lapse of statute of limitations ​ ​ (0.5) ​ Balance at December 31, 2018 ​ 15.1 ​ Changes in tax positions of prior years, net ​ 2.1 ​ Reductions for lapse of statute of limitations ​ ​ (0.8) ​ Balance at December 31, 2019 ​ 16.4 ​ Changes in tax positions of prior years, net ​ 2.1 ​ Reductions for lapse of statute of limitations ​ ​ (0.2) ​ Balance at December 31, 2020 ​ $ 18.3 ​ ​ Included in the balance of unrecognized tax benefits at December 31, 2020 are potential benefits of $18.3 million that, if recognized, would affect the Company’s income taxes and effective tax rate. The Company recognizes potential accrued interest and penalties related to unrecognized tax benefits in income taxes. To the extent interest and penalties are not ultimately assessed with respect to the settlement of uncertain tax positions, amounts accrued will be reduced and reflected as a reduction of the Company’s income taxes. Interest accrued related to the balance of unrecognized tax benefits totaled $0.1 million as of December 31, 2020 and 2019. ​ The Company is no longer subject to U.S. federal income tax audits for years before 2015. The Company is routinely involved in federal, state, local income and excise tax audits, and foreign tax audits.

PENSION AND POST-RETIREMENT PLA

PENSION AND POST-RETIREMENT PLANS	12 Months Ended
	Dec. 31, 2020
PENSION AND POST-RETIREMENT PLANS
PENSION AND POST-RETIREMENT PLANS	11. PENSION AND POST-RETIREMENT PLANS ​ Non-bargaining Plans: ​ The Company has two funded qualified single-employer defined benefit pension plans that cover certain non- bargaining unit employees and bargaining unit employees. In addition, the Company has plans that provide certain retiree health care and life insurance benefits to substantially all salaried, non-bargaining employees hired before 2008 and to certain bargaining unit employees. Employees are generally eligible for such benefits upon retirement and completion of a specified number of years of service. The Company does not pre-fund these health care and life insurance benefits, and has the right to modify or terminate certain of these plans in the future. Most non-bargaining retirees pay a portion of the benefit costs. ​ Plan Administration, Investments and Asset Allocations: The Company has a Benefits Investment Committee that meets regularly with investment advisors to establish investment policies, direct investments and select investment options for the qualified plans. The Benefits Investment Committee is also responsible for appointing investment managers and monitoring their performance. The Company’s investment policy permits investments in marketable equity securities, such as domestic and foreign stocks, domestic and foreign bonds, venture capital, real estate investments, and cash equivalents. The Company’s investment policy does not permit direct investment in certain types of assets, such as options or commodities, or the use of certain strategies, such as short selling or the purchase of securities on margin. ​ The Company’s investment strategy for its qualified pension plan assets is to achieve a diversified mix of investments that provides for long-term growth at an acceptable level of risk, and to provide sufficient liquidity to fund ongoing benefit payments. The Company has engaged a number of investment managers to implement various investment strategies to achieve the desired asset class mix, liquidity and risk diversification objectives. ​ The Company’s target and actual asset allocations at December 31, 2020 and 2019 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Asset Categories Target 2020 2019 Domestic equity securities 53 % 60 % 59 % International equity securities 15 % 17 % 17 % Debt securities 22 % 17 % 17 % Real estate 5 % 5 % 6 % Other and cash 5 % 1 % 1 % Total 100 % 100 % 100 % ​ The Company’s investments in equity securities primarily include domestic large-cap and mid-cap companies, but also includes an allocation to small-cap and international equity securities. Equity investments do not include any direct holdings of the Company’s stock but may include such holdings to the extent that the stock is included as part of certain mutual fund holdings. Debt securities include investment-grade and high-yield corporate bonds from diversified industries, mortgage-backed securities, and U.S. Treasuries. Other types of investments include funds that invest in commercial real estate assets. All assets within specific funds are allocated to the target asset allocation of the fund. ​ The expected return on plan assets is principally based on the Company’s historical returns combined with the Company’s long-term future expectations regarding asset class returns, the mix of plan assets, and inflation assumptions. Actual return on plan assets for the periods presented are as follows: ​ ​ ​ ​ ​ Actual Return on Plan Assets Returns One-year return 12.0 % Three-year return 8.7 % Five-year return 9.8 % Long-term average return (since plan inception in 1989) 8.5 % ​ The Company’s pension plan assets are held in a master trust and are stated at estimated fair values of the underlying investments. Purchases and sales of securities are recorded on a trade-date basis. Interest income is recorded on the accrual basis. Dividends are recorded on the ex-dividend date. ​ Equity Securities: Domestic and international common stocks are valued by obtaining quoted prices on recognized and highly liquid exchanges. ​ Fixed Income Securities: Corporate bonds and U.S. government treasury and agency securities are valued based upon the closing price reported in the market in which the security is traded. U.S. government agency and corporate asset-backed securities may utilize models, such as a matrix pricing model, that incorporate other observable inputs when broker/dealer quotes are not available, such as cash flow, security structure, or market information. ​ Real Estate Funds: The fair value of real estate funds is determined by the issuer based on their net asset value (“NAV”). NAV is determined by dividing the fund’s net assets, as recorded in the fund’s audited financial statements, by the number of units outstanding at the valuation date. Fair value for underlying investments in real estate is determined through independent property appraisals. ​ The fair values of the Company’s pension plan assets at December 31, 2020 and 2019 by asset category were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at December 31, 2020 ​ ​ ​ Quoted Prices in Significant Significant ​ ​ ​ ​ ​ Active Markets ​ Observable ​ Unobservable Asset Category (in millions) ​ Total ​ (Level 1) ​ Inputs (Level 2) ​ Inputs (Level 3) Cash ​ $ 3.8 ​ $ 3.8 ​ $ — ​ $ — ​ Equity securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. large-cap ​ 71.3 ​ 28.9 ​ 42.4 ​ — ​ U.S. mid- and small-cap ​ 54.3 ​ 36.2 ​ 18.1 ​ — ​ International large-cap ​ 7.0 ​ — ​ 7.0 ​ — ​ Fixed income securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasuries ​ 12.0 ​ — ​ 12.0 ​ — ​ Investment grade U.S. corporate bonds ​ ​ 22.5 ​ — ​ 22.5 ​ — ​ Total ​ ​ 170.9 ​ $ 68.9 ​ $ 102.0 ​ $ — ​ Investment measured at NAV (1) ​ ​ 41.9 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total plan assets ​ $ 212.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at December 31, 2019 ​ ​ ​ Quoted Prices in Significant Significant ​ ​ ​ ​ ​ Active Markets ​ Observable ​ Unobservable Asset Category (in millions) ​ Total ​ (Level 1) ​ Inputs (Level 2) ​ Inputs (Level 3) Cash ​ $ 6.3 ​ $ 6.3 ​ $ — ​ $ — ​ Equity securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. large-cap ​ 62.4 ​ 23.7 ​ 38.7 ​ — ​ U.S. mid- and small-cap ​ 49.6 ​ 33.9 ​ 15.7 ​ — ​ International large-cap ​ 6.6 ​ — ​ 6.6 ​ — ​ Fixed income securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasuries ​ 14.1 ​ — ​ 14.1 ​ — ​ Investment grade U.S. corporate bonds ​ 18.2 ​ — ​ 18.2 ​ — ​ High-yield U.S. corporate bonds ​ 0.1 ​ — ​ 0.1 ​ — ​ Total ​ ​ 157.3 ​ $ 63.9 ​ $ 93.4 ​ $ — ​ Investment measured at NAV (1) ​ ​ 37.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total plan assets ​ $ 194.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Real estate funds for which fair value is measured using the NAV per share as a practical expedient are not leveled within the fair value hierarchy and are included as a reconciling item to total plan assets. ​ Contributions to each of the qualified single-employer defined benefit pension plans are determined annually by the Company’s pension administrative committee, based upon the actuarially determined minimum required contribution under the Employee Retirement Income Security Act of 1974 (“ERISA”), as amended, the Pension Protection Act of 2006, and the maximum deductible contribution allowed for tax purposes. The Company’s funding policy is to contribute cash to its pension plans so that it meets at least the minimum contribution requirements. In 2020 and 2019, the Company contributed $9.0 million and $10.0 million, respectively, in pension contributions in these plans. There were no contributions to the plans in 2018. ​ The benefit formulas for employees who are members of collective bargaining units are determined according to the collective bargaining agreements, either using final average pay as the base or a flat dollar amount per year of service. ​ Effective December 31, 2011, the Company froze benefit accruals under the final average pay formula for salaried, non-bargaining unit employees hired before January 1, 2008 and transitioned them to the same cash balance formula for employees hired on or after January 1, 2008. Retirement benefits under the cash balance formula are based on a fixed percentage of employee eligible compensation, plus interest. The plan interest credit rate will vary from year to year based on the ten-year U.S. Treasury rate. ​ Benefit Plan Assets and Obligations: ​ The status of the funded qualified defined benefit pension plans and the unfunded post-retirement benefit plans at December 31, 2020 and 2019 are shown below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Post-retirement ​ ​ Pension Benefits ​ Benefits ​ ​ December 31, ​ December 31, ​ (In millions) 2020 2019 2020 2019 Change in Benefit Obligation: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Benefit obligation at beginning of year ​ $ 239.9 ​ $ 217.4 ​ $ 26.0 ​ $ 22.2 ​ Service cost ​ 5.1 ​ 4.7 ​ 0.5 ​ 0.4 ​ Interest cost ​ 7.9 ​ 9.3 ​ 0.8 ​ 0.9 ​ Plan participants’ contributions ​ — ​ — ​ 0.8 ​ 0.8 ​ Actuarial loss ​ 23.9 ​ 22.2 ​ 2.7 ​ 3.4 ​ Benefits paid, net of subsidies received ​ (12.5) ​ (12.2) ​ (1.7) ​ (1.7) ​ Expenses paid ​ (1.2) ​ (1.5) ​ — ​ — ​ Benefit obligation at end of year ​ ​ 263.1 ​ ​ 239.9 ​ ​ 29.1 ​ ​ 26.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Change in Plan Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value of plan assets at beginning of year ​ ​ 194.8 ​ ​ 162.2 ​ ​ — ​ ​ — ​ Actual return on plan assets ​ 22.7 ​ 36.3 ​ — ​ — ​ Plan participants’ contributions ​ — ​ — ​ 0.8 ​ 0.8 ​ Employer contributions ​ 9.0 ​ 10.0 ​ 0.9 ​ 0.9 ​ Benefits paid, net of subsidies received ​ (12.5) ​ (12.2) ​ (1.7) ​ (1.7) ​ Expenses paid ​ (1.2) ​ (1.5) ​ — ​ — ​ Fair value of plan assets at end of year ​ 212.8 ​ 194.8 ​ — ​ — ​ Funded Status and Recognized Liability ​ $ (50.3) ​ $ (45.1) ​ $ (29.1) ​ $ (26.0) ​ ​ Qualified pension and post-retirement benefits plans liabilities recognized in the Consolidated Balance Sheets and expenses recognized in accumulated other comprehensive income (loss) at December 31, 2020 and 2019 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Post-retirement ​ ​ Pension Benefits ​ Benefits ​ ​ December 31, ​ December 31, ​ (In millions) 2020 2019 2020 2019 Non-current assets ​ $ 1.0 ​ $ 1.0 ​ $ — ​ $ — ​ Current liabilities ​ ​ — ​ ​ — ​ ​ (1.0) ​ ​ (1.0) ​ Non-current liabilities, net ​ (51.3) ​ (46.1) ​ (28.1) ​ (25.0) ​ Total ​ $ (50.3) ​ $ (45.1) ​ $ (29.1) ​ $ (26.0) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss, net of taxes ​ $ (64.2) ​ $ (56.2) ​ $ (4.4) ​ $ (2.8) ​ Prior service credit, net of taxes ​ 2.5 ​ 4.3 ​ 16.6 ​ 19.1 ​ Total ​ $ (61.7) ​ $ (51.9) ​ $ 12.2 ​ $ 16.3 ​ ​ The information for qualified defined benefit pension plans with an accumulated benefit obligation in excess of plan assets at December 31, 2020 and 2019 are shown below: ​ ​ ​ ​ ​ ​ ​ ​ ​ (In millions) 2020 2019 Projected benefit obligation ​ $ 261.4 ​ $ 238.3 ​ Accumulated benefit obligation ​ $ 260.9 ​ $ 237.9 ​ Fair value of plan assets ​ $ 210.0 ​ $ 192.2 ​ ​ Unrecognized gains and losses of the post-retirement benefit plans are amortized over five years . Although current health care costs are expected to increase, the Company attempts to mitigate these increases by maintaining caps on certain of its benefit plans, using lower cost health care plan options where possible, requiring that certain groups of employees pay a portion of their benefit costs, self-insuring for certain insurance plans, encouraging wellness programs for employees, and implementing measures to mitigate future benefit cost increases. ​ Components of the net periodic benefit cost and other amounts recognized in other comprehensive income (loss) for the qualified pension plans and the post-retirement benefit plans during 2020, 2019 and 2018 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension Benefits ​ Post-retirement Benefits ​ ​ December 31, ​ December 31, ​ (In millions) 2020 2019 2018 2020 2019 2018 Components of Net Periodic Benefit Cost (Benefit): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Service cost ​ $ 5.1 ​ $ 4.7 ​ $ 4.4 ​ $ 0.5 ​ $ 0.4 ​ $ 0.6 ​ Interest cost ​ 7.9 ​ 9.3 ​ 8.6 ​ 0.8 ​ 0.9 ​ 1.0 ​ Expected return on plan assets ​ (14.0) ​ (11.9) ​ (13.5) ​ — ​ — ​ — ​ Amortization of net loss (gain) ​ 4.5 ​ 5.2 ​ 4.6 ​ 0.5 ​ (0.1) ​ 1.5 ​ Amortization of prior service credit ​ (2.3) ​ (2.3) ​ (2.3) ​ (3.7) ​ (3.8) ​ (3.8) ​ Net periodic benefit cost ​ ​ 1.2 ​ ​ 5.0 ​ ​ 1.8 ​ ​ (1.9) ​ ​ (2.6) ​ ​ (0.7) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income, net of tax: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss (gain) ​ ​ 11.4 ​ ​ (1.7) ​ ​ 7.8 ​ ​ 2.0 ​ ​ 2.5 ​ ​ (4.7) ​ Amortization of net (loss) gain ​ (3.4) ​ (3.9) ​ (3.5) ​ (0.3) ​ 0.2 ​ (1.1) ​ Amortization of prior service credit ​ 1.7 ​ 1.7 ​ 1.7 ​ 2.8 ​ 2.8 ​ 2.8 ​ Total recognized in other comprehensive loss (income) ​ ​ 9.7 ​ ​ (3.9) ​ ​ 6.0 ​ ​ 4.5 ​ ​ 5.5 ​ ​ (3.0) ​ Total recognized in net periodic benefit cost and other comprehensive loss (income) ​ $ 10.9 ​ $ 1.1 ​ $ 7.8 ​ $ 2.6 ​ $ 2.9 ​ $ (3.7) ​ ​ The weighted average assumptions used to determine benefit information during 2020, 2019 and 2018 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension Benefits ​ Post-retirement Benefits ​ ​ December 31, ​ December 31, ​ ​ 2020 2019 2018 2020 2019 2018 Discount rate (1) 2.50 % 3.40 % 4.40 % 2.70 % 3.50 % 4.50 % Expected return on plan assets 7.25 % 7.50 % 7.50 % ​ ​ ​ ​ ​ ​ Rate of compensation increase 3.00 % 3.00 % 3.00 % 3.00 % 3.00 % 3.00 % Cash balance interest credit rate ​ 0.75 - 3.25 % 1.75 - 3.75 % 3.01 % ​ ​ ​ ​ ​ ​ Initial health care cost trend rate: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pre-65 group ​ ​ ​ ​ ​ ​ ​ 5.30 % 5.70 % 6.00 % Post-65 group ​ ​ ​ ​ ​ ​ ​ 5.40 % 5.90 % 6.30 % Ultimate health care cost trend rate ​ ​ ​ ​ ​ ​ ​ 4.40 % 4.40 % 4.40 % Year ultimate health care cost trend rate is reached: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pre-65 group ​ ​ ​ ​ ​ ​ ​ 2037 ​ 2037 ​ 2037 ​ Post-65 group ​ ​ ​ ​ ​ ​ ​ 2036 ​ 2036 ​ 2036 ​ (1) The Company derives a single equivalent rate utilizing a yield curve constructed from a portfolio of high-quality corporate bonds with various maturities. ​ Non-qualified Pension Plans: The Company has non-qualified supplemental pension plans covering certain employees and retirees, which provide for incremental pension payments from the Company’s general funds so that total pension benefits would be substantially equal to amounts that would have been payable from the Company’s qualified pension plans if it were not for limitations imposed by income tax law. A few employees and retirees receive additional supplemental pension benefits. Non-qualified pension plan liabilities recognized in the Consolidated Balance Sheets and expenses recognized in accumulated other comprehensive income (loss) at December 31, 2020 and 2019 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Non-qualified ​ Pension Benefits ​ December 31, ​ (In millions) ​ 2020 2019 Current liabilities ​ $ (1.7) ​ $ (2.1) ​ Non-current liabilities, net ​ ​ (2.6) ​ ​ (2.3) ​ Total ​ $ (4.3) ​ $ (4.4) ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss, net of taxes ​ $ (0.8) ​ $ (0.6) ​ Prior service credit, net of taxes ​ ​ 0.1 ​ ​ 0.2 ​ Total ​ $ (0.7) ​ $ (0.4) ​ ​ Discount rates of 1.8 percent and 2.8 percent were used in determining the 2020 and 2019 non-qualified pension plan obligations, respectively. ​ Estimated Benefit Payments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Non-qualified ​ ​ ​ ​ Pension ​ Pension ​ Post-retirement ​ Year (in millions) ​ Benefits ​ Benefits ​ Benefits (1) 2021 ​ $ 14.0 ​ $ 1.7 ​ $ 1.0 ​ 2022 ​ 14.4 ​ — ​ 1.0 ​ 2023 ​ 14.6 ​ 2.2 ​ 1.0 ​ 2024 ​ 14.7 ​ — ​ 1.1 ​ 2025 ​ 14.9 ​ — ​ 1.1 ​ 2026-2030 ​ ​ 76.2 ​ ​ 0.6 ​ ​ 5.5 ​ Total ​ $ 148.8 ​ $ 4.5 ​ $ 10.7 ​ (1) Net of plan participants’ contributions and Medicare Part D subsidies. ​ Defined Contribution Plans: The Company sponsors defined contribution plans that qualify under Sections 401(a) and 401(k) of the Internal Revenue Code. The Company may make discretionary matching contributions equal to a specified percentage of each participant’s 401(k) contributions and makes other non-discretionary contributions. For the year ended December 31, 2020, the Company provided discretionary matching contributions of up to 3 percent of eligible employee compensation. The Company’s matching contributions expensed in 2020, 2019 and 2018 were $3.0 million, $2.9 million and $2.4 million, respectively. ​ The Company may also provide a discretionary profit sharing contribution under the qualified defined contribution plans, to salaried, non-bargaining unit employees, if both a minimum threshold of Company performance is achieved and the Board has approved the profit sharing contribution. For certain eligible employees, supplemental profit sharing contributions are credited under a non-qualified plan to be paid after separation from service from the Company’s general funds so that total profit sharing contributions would be substantially equal to amounts that would have been contributed to the Company’s qualified defined contribution plans if it were not for limitations imposed by income tax law. Discretionary profit sharing contributions expensed in 2020, 2019 and 2018 were $2.2 million, $0.5 million and $1.4 million, respectively. ​ Multi-employer Bargaining Plans: ​ The Company contributes to multi-employer defined benefit pension plans under the terms of collective-bargaining agreements that cover its bargaining unit employees. Contributions are generally based on amounts paid for union labor or cargo volume. The risks of participating in multi-employer plans are different from single-employer plans because assets contributed to the multi-employer plan by one employer may be used to provide benefits to employees of other participating employers. Additionally, if one employer stops contributing to the plan, the unfunded obligations of the plan may be borne by the remaining participating employers. ​ The multi-employer pension plans are subject to the plan termination insurance provisions of ERISA and are paying premiums to the Pension Benefit Guaranty Corporation (“PBGC”). The statutes provide that an employer who withdraws from, or significantly reduces its contribution obligation to, a multi-employer plan generally will be required to continue funding its proportional share of the plan’s unfunded vested benefits. As of December 31, 2020, the Company’s estimated benefit plan withdrawal obligations were $260.0 million. Except as described in Note 12, no withdrawal obligations have been recorded by the Company in the Consolidated Balance Sheets at December 31, 2020 and 2019, as the Company has no present intention of withdrawing from and does not anticipate termination of any of these plans. ​ Information regarding the Company’s participation in multi-employer pension plans is outlined in the table below. The “EIN/Pension Plan Number” column provides the Employer Identification Number (“EIN”) and the three-digit plan number, if applicable. Unless otherwise noted, the most recent Pension Protection Act zone status available in 2020 and 2019 is for the plan’s year-end at December 31, 2020 and 2019, respectively. The zone status is based on information that the Company received from the plan and is certified by the plan’s actuary. Among other factors, plans in the red zone are generally less than 65 percent funded; plans in the orange zone are both a) less than 80 percent funded and b) have an accumulated/expected funding deficiency in any of the next six plan years, net of any amortization extensions; plans in the yellow zone meet either one of the criteria mentioned in the orange zone; and plans in the green zone are at least 80 percent funded. The funding improvement plan (“FIP”) or rehabilitation plan (“RP”) column indicates the status which is either pending or has been implemented. The last column lists the expiration dates of the collective-bargaining agreements to which the plans are subject. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Protection Act ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Zone as of ​ FIP/RP Status ​ ​ ​ Contributions of Matson ​ ​ ​ ​ ​ ​ EIN/Pension ​ ​ ​ December 31, ​ Pending/ ​ 5% ​ (in millions) ​ Surcharge ​ Expiration Pension Funds Plan Number Notes 2020 2019 Implemented Contributor 2020 2019 2018 Imposed Date (2) American Radio Association Pension Fund 13-6161999-001 ​ ​ Green Green Implemented ​ Yes ​ $ 1.0 ​ $ 1.1 ​ $ 1.0 No 6/15/2028 ​ Hawaii Terminals Multiemployer Pension Plan 20-0389370-001 ​ (1) ​ Yellow Orange Implemented ​ Yes ​ ​ 5.8 ​ ​ 5.7 ​ ​ 5.7 No 6/30/2022 ​ Hawaii Stevedoring Multiemployer Retirement Plan 99-0314293-001 ​ (1) ​ Green Yellow Implemented ​ Yes ​ 4.6 ​ 4.4 ​ 4.3 No 6/30/2022 ​ Master, Mates and Pilots Pension Plan 13-6372630-001 ​ ​ ​ Green Green No ​ Yes ​ 3.2 ​ 3.4 ​ 3.0 No ​ 6/15/2027, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 6/15/2028 ​ Masters, Mates and Pilots Adjustable Pension Plan 37-1719247-001 ​ ​ ​ Green Green No ​ Yes ​ 1.8 ​ 1.9 ​ 1.7 No ​ 6/15/2027, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 6/15/2028 ​ MEBA Pension Trust - Defined Benefit Plan 51-6029896-001 ​ ​ ​ Green Green No ​ Yes ​ 4.1 ​ 4.3 ​ 4.0 No 6/15/2022, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 6/15/2028 ​ OCU Pension Trust Plan 26-1574440-001 ​ ​ ​ Green Green No ​ No ​ 0.2 ​ 0.2 ​ 0.2 No 6/30/2023 ​ MFOW Supplementary Pension Plan ​ 94-6201677-001 ​ ​ ​ Yellow ​ Green ​ No ​ Yes ​ ​ 0.1 ​ ​ 0.1 ​ ​ — ​ No ​ 6/30/2021 ​ SIU Pacific District Pension Plan ​ 94-6061923-001 ​ ​ ​ Green ​ Green ​ No ​ Yes ​ ​ 1.3 ​ ​ 1.5 ​ ​ 1.2 ​ No ​ 6/30/2021 ​ Alaska Teamster - Employer Pension Plan ​ 92-6003463-024 ​ ​ ​ Red ​ Red ​ Implemented ​ Yes ​ ​ 3.3 ​ ​ 1.9 ​ ​ 1.9 ​ Yes ​ 6/30/2021, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 6/30/2022, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 6/30/2023, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 6/30/2024 ​ All Alaska Longshore Pension Plan ​ 91-6085352-001 ​ ​ ​ Green ​ Green ​ No ​ Yes ​ ​ 1.3 ​ ​ 1.2 ​ ​ 1.0 ​ No ​ 6/30/2022 ​ Western Conference of Teamsters Pension Plan ​ 91-6145047-001 ​ ​ ​ Green ​ Green ​ No ​ No ​ ​ 1.6 ​ ​ 1.5 ​ ​ 1.4 ​ No ​ 3/31/2023 ​ Western Conference of Teamsters Supplemental Benefit Trust ​ 95-3746907-001 ​ ​ ​ Green ​ Green ​ No ​ No ​ ​ — ​ ​ — ​ ​ — ​ No ​ 3/31/2023 ​ OPEIU Local 153 Pension Plan ​ 13-2864289-001 ​ ​ ​ Red ​ Red ​ Implemented ​ No ​ ​ 0.1 ​ ​ 0.1 ​ ​ 0.1 ​ No ​ 11/9/2023 ​ Seafarers Pension Plan ​ 13-6100329-001 ​ (3) ​ Green ​ Green ​ No ​ No ​ ​ — ​ ​ — ​ ​ — ​ No ​ 6/30/2022 ​ Total ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 28.4 ​ $ 27.3 ​ $ 25.5 ​ ​ ​ ​ ​ (1) The Hawaii Terminals Multiemployer Pension Plan merged into the Hawaii Stevedoring Multiemployer Retirement Plan effective January 1, 2021 and formally known as the Hawaii Longshore Pension Plan. (2) Represents the expiration date of the collective bargaining agreement. (3) The Company does not make contributions directly to the Seafarers Pension Plan. Instead, contributions are made to the Seafarers Health and Benefits Plan, and are subsequently re-allocated to the Seafarers Pension Plan at the discretion of the plan Trustee. ​ The Company also contributes to multi-employer plans that provide post-retirement health and other benefits other than pensions under the terms of collective-bargaining agreements. Benefits provided to active and retired employees and their eligible dependents under these plans include medical, dental, vision and prescription drug. These plans are not subject to the PBGC plan termination and withdrawal liability provisions of ERISA applicable to multi-employer defined benefit pension plans. Contributions for these multi-employer postretirement health and other benefits were $32.5 million, $32.8 million and $30.0 million in 2020, 2019 and 2018, respectively. ​ Multi-employer Defined Contribution Plans: multi-employer defined contribution pension plans. These plans are not subject to the withdrawal liability provisions of ERISA or the PBGC applicable to multi-employer defined benefit pension plans. Contributions made to these plans by the Company were $5.1 million, $5.3 million and $4.8 million in 2020, 2019 and 2018, respectively.

MULTI-EMPLOYER WITHDRAWAL LIABI

MULTI-EMPLOYER WITHDRAWAL LIABILITIES	12 Months Ended
	Dec. 31, 2020
MULTI-EMPLOYER WITHDRAWAL LIABILITIES
MULTI-EMPLOYER WITHDRAWAL LIABILITIES	12. MULTI-EMPLOYER WITHDRAWAL LIABILITIES ​ Horizon ceased all of its operations in Puerto Rico during the first quarter of 2015, which resulted in a mass withdrawal from its multi-employer ILA-PRSSA pension fund. The Company assumed this liability as part of the acquisition of Horizon on May 29, 2015. The Company estimated the mass withdrawal liability based upon the required undiscounted quarterly payment of approximately $1.0 million to be paid to the ILA-PRSSA pension fund over a period which ends in March 2040, discounted to present value using the Company’s incremental borrowing rate. Future estimated annual payments to be paid to the ILA-PRSSA pension fund as of December 31, 2020 were as follows: ​ ​ ​ ​ ​ Year (in millions) ​ Total 2021 $ 4.1 2022 ​ ​ 4.1 2023 ​ ​ 4.1 2024 ​ ​ 4.1 2025 ​ ​ 4.1 Thereafter ​ ​ 59.7 Total remaining future undiscounted payments due to the ILA-PRSSA pension fund ​ ​ 80.2 Less: amount representing interest ​ ​ (23.3) Present value of multi-employer withdrawal liability ​ ​ 56.9 Current portion of multi-employer withdrawal liability (see Note 2) ​ ​ (4.1) Long-term portion of multi-employer withdrawal liability (see Note 2) $ 52.8 ​ Furthermore, the Company assumed a partial withdrawal liability related to the Local 153 Fund of the OPEIU. The partial withdrawal liability resulted from a decline in the number of contribution base units related to the Local 153 Fund caused by Horizon terminating all of its operations in Puerto Rico during the first quarter of 2015. The Company included the partial withdrawal liability of

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	12 Months Ended
	Dec. 31, 2020
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS).
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	13. ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) ​ Changes in accumulated other comprehensive income (loss) by component, net of tax, are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Non- ​ ​ Accumulated ​ ​ ​ ​ ​ Post- ​ Qualified ​ ​ ​ ​ Other ​ ​ Pension ​ Retirement ​ Pension ​ ​ ​ ​ Comprehensive (In millions) ​ Benefits ​ Benefits ​ Benefits ​ Other ​ Income (Loss) Balance at December 31, 2018 ​ $ (55.8) ​ $ 21.7 ​ $ (0.1) ​ $ (0.3) ​ $ (34.5) ​ Amortization of prior service cost ​ (1.7) ​ ​ (2.6) ​ ​ (0.1) ​ ​ (0.1) ​ (4.5) ​ Amortization of net loss (gain) ​ ​ 5.6 ​ ​ (2.8) ​ ​ (0.2) ​ ​ 0.1 ​ 2.7 ​ Other adjustments ​ ​ — ​ — ​ — ​ (0.6) ​ (0.6) ​ Balance at December 31, 2019 ​ (51.9) ​ 16.3 ​ (0.4) ​ (0.9) ​ (36.9) ​ Amortization of prior service cost ​ (1.8) ​ ​ (2.8) ​ ​ (0.1) ​ ​ — ​ (4.7) ​ Amortization of net loss (gain) ​ (8.0) ​ ​ (1.3) ​ ​ (0.1) ​ ​ — ​ (9.4) ​ Foreign currency exchange ​ ​ — ​ ​ — ​ ​ — ​ ​ 0.5 ​ ​ 0.5 ​ Other adjustments ​ — ​ ​ — ​ ​ — ​ ​ (0.3) ​ (0.3) ​ Balance at December 31, 2020 ​ $ (61.7) ​ $ 12.2 ​ $ (0.6) ​ $ (0.7) ​ $ (50.8) ​ ​ Other comprehensive income (loss) in the Consolidated Statements of Income and Comprehensive Income is shown net of tax benefit (expense) of $4.2 million, $(0.3) million and $0.2 million for the years ended December 2020, 2019 and 2018, respectively.

EARNINGS PER-SHARE

EARNINGS PER-SHARE	12 Months Ended
	Dec. 31, 2020
EARNINGS PER-SHARE
EARNINGS PER-SHARE	14. EARNINGS PER SHARE ​ Basic earnings per share are determined by dividing net income by the weighted-average common shares outstanding during the year. The calculation of diluted earnings per share includes the dilutive effect of unexercised non-qualified stock options and non-vested stock units. The computation of weighted average dilutive shares outstanding excluded a nominal amount of anti-dilutive non-qualified stock options for each of the years 2020, 2019 and 2018. ​ The denominators used to compute basic and diluted earnings per share for the years ended December 31, 2020, 2019 and 2018 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, 2020 ​ Year Ended December 31, 2019 ​ Year Ended December 31, 2018 ​ ​ ​ Weighted Per ​ ​ Weighted Per ​ ​ Weighted Per ​ ​ ​ ​ ​ Average ​ Common ​ ​ ​ ​ Average ​ Common ​ ​ ​ ​ Average ​ Common ​ ​ Net ​ Common ​ Share ​ Net ​ Common ​ Share ​ Net ​ Common ​ Share (In millions, except per share amounts) ​ Income ​ Shares ​ Amount ​ Income ​ Shares ​ Amount ​ Income ​ Shares ​ Amount Basic: ​ $ 193.1 43.1 ​ $ 4.48 ​ $ 82.7 42.8 ​ $ 1.93 ​ $ 109.0 42.7 ​ $ 2.55 ​ Effect of Dilutive Securities: ​ ​ ​ 0.4 ​ ​ (0.04) ​ ​ ​ 0.5 ​ ​ (0.02) ​ ​ ​ 0.3 ​ ​ (0.02) ​ Diluted: ​ $ 193.1 ​ 43.5 ​ $ 4.44 ​ $ 82.7 ​ 43.3 ​ $ 1.91 ​ $ 109.0 ​ 43.0 ​ $ 2.53 ​ ​

SHARE-BASED AWARDS

SHARE-BASED AWARDS	12 Months Ended
	Dec. 31, 2020
SHARE-BASED AWARDS
SHARE-BASED AWARDS	15. SHARE-BASED AWARDS ​ The Company has share-based compensation plans which are described as follows: ​ 2016 Incentive Compensation Plan: The 2016 Incentive Compensation Plan (the “2016 Plan”) serves as a successor to the 2007 Incentive Compensation Plan and all other predecessor plans. No further grants will be made under the predecessor stock option plans. Under the 2016 Plan, 2.5 million shares of common stock were reserved for issuance. Shareholders approved the 2016 Plan at the 2016 Annual Meeting of Shareholders. ​ The 2016 Plan consists of four separate incentive compensation programs: (i) the discretionary grant program, (ii) the stock issuance program, (iii) the incentive bonus program, and (iv) the automatic grant program for the non- employee members of the Company’s Board of Directors. Share-based compensation is generally awarded under three of the four programs, as more fully described below. ​ Discretionary Grant Program percent of the fair market value (defined as the closing market price) of the Company’s common stock on the date of the grant. Options generally become exercisable ratably over three years and have a maximum contractual term of 10 years . ​ Stock Issuance Program — Under the Stock Issuance Program, shares of common stock, restricted stock units or performance shares may be granted. Time-based equity awards generally vest ratably over three years . Provided certain three-year performance targets are achieved, performance-based equity awards generally vest on the three-year anniversary date of the grant. ​ Automatic Grant Program — At each annual shareholder meeting, non-employee directors will receive an award of restricted stock units that entitle the holder to an equivalent number of shares of common stock upon vesting, under the automatic grant program. Awards of restricted stock units granted under the program generally vest on the one-year anniversary of the grant date. ​ The shares of common stock authorized to be issued under the 2016 Plan may be drawn from shares of the Company’s authorized but unissued common stock or from shares of its common stock that the Company acquires, including shares purchased on the open market or in private transactions. ​ Share-based compensation expense and other information related to share-based awards for the years ended December 31, 2020, 2019 and 2018 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, Share-based compensation expense, net of estimated forfeitures (in millions) 2020 2019 2018 Share-based compensation expense ​ $ 18.8 ​ $ 11.3 ​ $ 12.1 ​ Intrinsic value of options exercised ​ $ 5.8 ​ $ 0.5 ​ $ 0.5 ​ Tax benefit realized upon stock vesting ​ $ 3.3 ​ $ 2.0 ​ $ 2.7 ​ Fair value of stock vested ​ $ 13.1 ​ $ 8.2 ​ $ 10.8 ​ ​ As of December 31, 2020, there was no unrecognized compensation cost related to non-vested stock options. As of December 31, 2020, unrecognized compensation cost related to non-vested restricted stock units and performance-based equity awards was $17.7 million. Unrecognized compensation cost is expected to be recognized over a weighted average period of approximately 1.7 years. ​ Stock option activity for the year ended December 31, 2020 was as follows (in thousands, except weighted average exercise price and weighted average contractual life): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Weighted ​ ​ ​ ​ ​ Average ​ Average ​ Aggregate ​ ​ 2007 Plan ​ Exercise ​ Contractual ​ Intrinsic ​ ​ Shares ​ Price ​ Life ​ Value Outstanding at December 31, 2019 173 $ 22.30 ​ ​ ​ ​ ​ ​ Exercised (172) ​ $ 22.31 ​ ​ ​ ​ ​ ​ Outstanding at December 31, 2020 1 $ 20.84 0.1 ​ $ 35 ​ Exercisable at December 31, 2020 1 $ 20.84 0.1 ​ $ 35 ​ ​ The following table summarizes non-vested restricted stock unit activity through December 31, 2020 (in thousands, except weighted average grant-date fair value amounts): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2007 Plan 2016 Plan Total Weighted ​ ​ Restricted ​ Restricted ​ Restricted ​ Average Grant- ​ ​ ​ Stock Units ​ Stock Units ​ Stock Units ​ Date Fair Value Outstanding at December 31, 2019 8 770 778 ​ $ 33.39 ​ Granted ​ — ​ 341 ​ 341 ​ ​ 38.68 ​ Settlement of Performance Shares (1) ​ — ​ 38 ​ 38 ​ ​ 36.55 ​ Vested ​ (5) ​ (339) ​ (344) ​ ​ 34.86 ​ Canceled ​ — ​ (21) ​ (21) ​ ​ 34.59 ​ Outstanding at December 31, 2020 3 789 792 ​ $ 35.14 ​ (1) Represents shares paid out above target.

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2020
FAIR VALUE OF FINANCIAL INSTRUMENTS
FAIR VALUE OF FINANCIAL INSTRUMENTS	16. FAIR VALUE OF FINANCIAL INSTRUMENTS ​ The Company values its financial instruments based on the fair value hierarchy of valuation techniques for fair value measurements. Level 1 inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date. Level 2 inputs include quoted prices for similar assets and liabilities in active markets and inputs other than quoted prices observable for the asset or liability. Level 3 inputs are unobservable inputs for the asset or liability. If the technique used to measure fair value includes inputs from multiple levels of the fair value hierarchy, the lowest level of significant input determines the placement of the entire fair value measurement in the hierarchy. ​ The Company uses Level 1 inputs for the fair values of its cash, cash equivalents and restricted cash, and Level 2 inputs for its variable and fixed rate debt. The fair values of cash, cash equivalents and restricted cash, and variable rate debt approximate their carrying values due to the nature of the instruments. The fair value of fixed rate debt is calculated based upon interest rates available for debt with terms and maturities similar to the Company’s existing debt arrangements. ​ The carrying value and fair value of the Company’s financial instruments as of December 31, 2020 and 2019 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quoted Prices in ​ Significant ​ Significant ​ ​ ​ Total ​ ​ ​ Active Markets ​ Observable ​ Unobservable ​ ​ Carrying Value Total (Level 1) Inputs (Level 2) Inputs (Level 3) ​ (In millions) ​ December 31, 2020 ​ Fair Value Measurements at December 31, 2020 ​ Cash and cash equivalents ​ $ 14.4 ​ $ 14.4 ​ $ 14.4 ​ $ — ​ $ — ​ Restricted cash ​ $ 5.3 ​ $ 5.3 ​ $ 5.3 ​ $ — ​ $ — ​ Variable rate debt ​ $ 71.8 ​ $ 71.8 ​ $ — ​ $ 71.8 ​ $ — ​ Fixed rate debt ​ $ 688.3 ​ $ 686.7 ​ $ — ​ $ 686.7 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (In millions) December 31, 2019 ​ Fair Value Measurements at December 31, 2019 ​ Cash and cash equivalents ​ $ 21.2 ​ $ 21.2 $ 21.2 ​ $ — ​ $ — ​ Restricted cash ​ $ 7.2 ​ $ 7.2 ​ $ 7.2 ​ $ — ​ $ — ​ Variable rate debt ​ $ 379.1 ​ $ 379.1 ​ $ — ​ $ 379.1 ​ $ — ​ Fixed rate debt ​ $ 579.3 ​ $ 585.9 ​ $ — ​ $ 585.9 ​ $ — ​ ​

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2020
COMMITMENTS AND CONTINGENCIES
COMMITMENTS AND CONTINGENCIES	17. COMMITMENTS AND CONTINGENCIES ​ Commitments and contractual obligations, excluding debt obligations (see Note 8), lease commitments (see Note 9), pension and post-retirement plan commitments, and multi-employer bargaining plan withdrawal obligations (see Note 11 and 12), are as follows as of December 31, 2020: ​ ​ ​ ​ ​ ​ Commitments and Contractual Obligations (in millions) Total Standby letters of credit (1) ​ $ 8.1 ​ Bonds (2) ​ $ 33.2 ​ Vendor and other obligations (3) ​ $ 69.1 ​ (1) Standby letters of credit are required for the Company’s uninsured workers’ compensation and other insurance programs, and other needs. (2) Bonds are required for U.S. Customs and other related matters. (3) Vendor and other obligations include: (i) non-cancellable contractual capital project obligations; (ii) dry-docking related obligations; and (iii) other contractual obligations. Amounts are considered obligations if a contract has been agreed to specifying significant terms of the contract, and the amounts are not reflected in the Consolidated Balance Sheets. ​ These amounts are not recorded on the Company’s Consolidated Balance Sheets and it is not expected that the Company or its subsidiaries will be called upon to advance funds under these commitments. ​ Contingencies: Contingencies and other litigation related matters are described as follows: ​ Environmental Matters: The Company’s Ocean Transportation segment has certain risks that could result in expenditures for environmental remediation. The Company believes that based on all information available to it, the Company is currently in compliance, in all material respects, with applicable environmental laws and regulations. ​ Other Matters: The Company and its subsidiaries are parties to, or may be contingently liable in connection with other legal actions arising in the normal course of their businesses, the outcomes of which, in the opinion of management after consultation with counsel, would not have a material effect on the Company’s financial condition, results of operations, or cash flows.

QUARTERLY INFORMATION (Unaudite

QUARTERLY INFORMATION (Unaudited)	12 Months Ended
	Dec. 31, 2020
QUARTERLY INFORMATION (Unaudited)
QUARTERLY INFORMATION (Unaudited)	18. QUARTERLY INFORMATION (Unaudited) ​ Segment results by quarter for 2020 and 2019 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quarters in the Year Ended December 31, 2020 (In millions, except per share amounts) Q1 Q2 Q3 Q4 Operating Revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ocean Transportation ​ $ 400.9 ​ $ 410.8 ​ $ 498.3 ​ $ 543.9 ​ Logistics ​ 113.0 ​ 113.3 ​ 146.9 ​ 156.2 ​ Total Operating Revenue ​ $ 513.9 ​ $ 524.1 ​ $ 645.2 ​ $ 700.1 ​ Operating Income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ocean Transportation ​ $ 7.9 ​ $ 42.3 ​ $ 86.5 ​ $ 108.1 ​ Logistics ​ 5.1 ​ 8.9 ​ 11.9 ​ 9.6 ​ Total Operating Income ​ 13.0 ​ 51.2 ​ 98.4 ​ 117.7 ​ Interest expense, net ​ (8.6) ​ (8.2) ​ (5.7) ​ (4.9) ​ Other income (expense), net ​ ​ 0.6 ​ ​ 1.5 ​ ​ 2.4 ​ ​ 1.6 ​ Income before Income Taxes ​ 5.0 ​ 44.5 ​ 95.1 ​ 114.4 ​ Income Taxes ​ (1.2) ​ (11.7) ​ (24.2) ​ (28.8) ​ Net Income ​ $ 3.8 ​ $ 32.8 ​ $ 70.9 ​ $ 85.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic Earnings Per Share: ​ $ 0.09 ​ $ 0.76 ​ $ 1.65 ​ $ 1.99 ​ Diluted Earnings Per Share: ​ $ 0.09 ​ $ 0.76 ​ $ 1.63 ​ $ 1.96 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quarters in the Year Ended December 31, 2019 (In millions, except per share amounts) Q1 Q2 Q3 Q4 Operating Revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ocean Transportation ​ $ 397.9 ​ $ 415.4 ​ $ 437.2 ​ $ 416.1 ​ Logistics ​ 134.5 ​ 142.5 ​ 134.9 ​ 124.6 ​ Total Operating Revenue ​ $ 532.4 ​ $ 557.9 ​ $ 572.1 ​ $ 540.7 ​ Operating Income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ocean Transportation ​ $ 9.4 ​ $ 19.7 ​ $ 43.9 ​ $ 17.8 ​ Logistics ​ 8.1 ​ 11.3 ​ 11.3 ​ 7.6 ​ Total Operating Income ​ 17.5 ​ 31.0 ​ 55.2 ​ 25.4 ​ Interest expense, net ​ (4.6) ​ (6.1) ​ (6.2) ​ (5.6) ​ Other income (expense), net ​ ​ 0.6 ​ ​ 0.8 ​ ​ (0.5) ​ ​ 0.3 ​ Income before Income Taxes ​ 13.5 ​ 25.7 ​ 48.5 ​ 20.1 ​ Income Taxes ​ (1.0) ​ (7.3) ​ (12.3) ​ (4.5) ​ Net Income ​ $ 12.5 ​ $ 18.4 ​ $ 36.2 ​ $ 15.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic Earnings Per Share: ​ $ 0.29 ​ $ 0.43 ​ $ 0.84 ​ $ 0.36 ​ Diluted Earnings Per Share: ​ $ 0.29 ​ $ 0.43 ​ $ 0.84 ​ $ 0.36 ​ ​ The following infrequent transactions impacted the Company’s quarterly segment results during the year ended December 31, 2019. There were no infrequent transactions recorded during the year ended December 31, 2020. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quarters in the Year Ended December 31, 2019 (In millions) Q1 Q2 Q3 Q4 Income taxes - Discrete adjustments related to the Tax Act (1) ​ $ 2.9 ​ $ — ​ $ — ​ $ — ​ (1) Amounts relate to discrete adjustments as a result of applying the Tax Act during the year ended December 31, 2019.

SIGNIFICANT ACCOUNTING POLICI_2

SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2020
SIGNIFICANT ACCOUNTING POLICIES
Principles of Consolidation	Principles of Consolidation: The Consolidated Financial Statements include the accounts of Matson, Inc. and all wholly-owned subsidiaries, after elimination of intercompany amounts and transactions. Significant investments in businesses, partnerships, and limited liability companies in which the Company does not have a controlling financial interest, but has the ability to exercise significant influence, are accounted for under the equity method. The Company accounts for its investment in SSAT using the equity method of accounting (see Note 4).
Fiscal Year	Fiscal Year: The year end for Matson is December 31. The period end for MatNav occurred on the last Friday in December, except for Matson Logistics Warehousing, Inc. and Matson South Pacific Holdco Limited whose period closed on December 31. Included in these Consolidated Financial Statements are 52 weeks in the 2020, 2019 and 2018 fiscal years for MatNav.
Foreign Currency Transactions	Foreign Currency Transactions: The United States (U.S.) dollar is the functional currency for substantially all of the financial statements of the Company’s foreign subsidiaries. Foreign currency denominated assets and liabilities of the Company’s foreign subsidiaries are translated into U.S. dollars at exchange rates existing at the respective balance sheet dates. Translation adjustments resulting from fluctuations in exchange rates are recorded as a component of accumulated other comprehensive loss (gain) within shareholders’ equity. The Company translates the result of operations of its foreign subsidiaries at the average exchange rate during the respective periods. Gains and losses resulting from foreign currency transactions are included in Costs and Expenses in the Consolidated Statements of Income and Comprehensive Income.
Use of Estimates	Use of Estimates: The preparation of the Consolidated Financial Statements in conformity with accounting principles generally accepted in the U.S. requires management to make estimates and assumptions that affect the amounts reported. Estimates and assumptions are used for, but not limited to: impairment of investments; impairment of long-lived assets, intangible assets and goodwill; capitalized interest; allowance for doubtful accounts; legal contingencies; insurance reserves and other related liabilities; accrual estimates; pension and post-retirement estimates; multi-employer withdrawal liabilities; operating lease assets and liabilities; and income taxes. Future results could be materially affected if actual results differ from these estimates and assumptions.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash: Cash equivalents consist of highly-liquid investments with original maturities of three months or less. The Company carries these investments at cost, which approximates fair value. Outstanding checks in excess of funds on deposit totaled $19.9 million and $13.8 million at December 31, 2020 and 2019, respectively, and are included in current liabilities in the Consolidated Balance Sheets. Restricted cash relates to amounts that are subject to contractual restrictions and are not readily available. At December 31, 2020 and 2019, restricted cash was $5.3 million and $7.2 million, respectively, and are included in prepaid expenses and other assets in the Consolidated Balance Sheets.
Accounts Receivable, net	Accounts Receivable, net: Accounts receivable represent amounts due from trade customers arising in the normal course of business. Accounts receivable are shown net of allowance for doubtful accounts receivable in the Consolidated Balance Sheets. Allowance for doubtful accounts receivable is established by management based on estimates of collectability. Estimates of collectability are principally based on an evaluation of the current financial condition of the customer and the potential risks to collection, the customer’s payment history, expected future credit losses and other factors which are regularly monitored by the Company. ​ Changes in the allowance for doubtful accounts receivable for the three years ended December 31, 2020, 2019 and 2018 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at ​ Write-offs Balance at Year (in millions) Beginning of Year Expense (1) and Other End of Year 2020 ​ $ 4.3 ​ $ 2.9 ​ $ (0.9) ​ $ 6.3 ​ 2019 ​ $ 4.8 ​ $ 0.6 ​ $ (1.1) ​ $ 4.3 ​ 2018 ​ $ 4.6 ​ $ 0.8 ​ $ (0.6) ​ $ 4.8 ​ (1) Expense is shown net of amounts recovered from previously reserved doubtful accounts. ​
Allowance for Doubtful Accounts Receivable	​ Changes in the allowance for doubtful accounts receivable for the three years ended December 31, 2020, 2019 and 2018 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at ​ Write-offs Balance at Year (in millions) Beginning of Year Expense (1) and Other End of Year 2020 ​ $ 4.3 ​ $ 2.9 ​ $ (0.9) ​ $ 6.3 ​ 2019 ​ $ 4.8 ​ $ 0.6 ​ $ (1.1) ​ $ 4.3 ​ 2018 ​ $ 4.6 ​ $ 0.8 ​ $ (0.6) ​ $ 4.8 ​ (1) Expense is shown net of amounts recovered from previously reserved doubtful accounts.
Prepaid expenses and Other Assets	Prepaid Expenses and Other Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, Prepaid Expenses and Other Assets (in millions) 2020 2019 Prepaid fuel ​ $ 10.8 ​ $ 13.7 ​ Prepaid insurance and insurance related receivables ​ 7.5 ​ 13.4 ​ Prepaid operating expenses ​ ​ 5.4 ​ ​ 5.7 ​ Restricted cash - vessel construction obligations ​ ​ 5.3 ​ ​ 7.2 ​ Income tax receivables ​ ​ 0.3 ​ ​ 12.8 ​ Other ​ 8.8 ​ 9.7 ​ Total ​ $ 38.1 ​ $ 62.5 ​
Deferred Loan Fees	Deferred Loan Fees: The Company records deferred loan fees, excluding those related to the revolving credit facility, as a reduction to Total Debt in the Company’s Consolidated Balance Sheets in accordance with Accounting Standards Update (“ASU”) 2015-03, Interest-Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs (“ASU 2015-03”). These costs are being amortized over the life of the related debt using the effective interest method (see Note 8). ​ Deferred loan fees related to the Company’s revolving credit facility are recorded in other long-term assets in the Company’s Consolidated Balance Sheets, and are amortized using the straight-line method as the difference between that and the use of the effective interest method is not material.
Other Long-Term Assets	Other Long-Term Assets: Other long-term assets consist of the following at December 31, 2020 and 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, Other Long-Term Assets (in millions) 2020 2019 Vessel and equipment spare parts ​ $ 11.5 ​ $ 12.4 ​ Insurance related receivables ​ ​ 10.5 ​ ​ 10.6 ​ Deferred loan fees ​ 2.7 ​ 2.1 ​ Cloud computing software costs ​ 2.4 ​ — ​ Income tax receivables ​ ​ 2.1 ​ ​ 11.5 ​ Other ​ ​ 3.8 ​ ​ 1.2 ​ Total ​ $ 33.0 ​ $ 37.8 ​ ​
Property and Equipment	Property and Equipment: Property and equipment is stated at cost. Property and equipment is depreciated using the straight-line method over the estimated useful lives of the assets. The estimated useful lives of property and equipment range up to the following maximum life: ​ ​ ​ ​ ​ Classification Life Vessels 40 years ​ Machinery and equipment 30 years ​ Terminal facilities 35 years ​ ​
Capitalized Interest	Capitalized Interest: The Company capitalizes interest costs during the period the qualified assets are being readied for their intended use. The Company determined that the vessel construction costs are considered qualifying assets for the purposes of capitalizing interest on these assets. The amount of capitalized interest is calculated based on the amount of payments incurred related to the construction of these vessels using a weighted average interest rate. The weighted average interest rate is determined using the Company’s average borrowings outstanding during the period. Capitalized interest is included in vessel construction in progress in property and equipment in the Company’s Consolidated Balance Sheets (see Note 5). During the years ended December 31, 2020, 2019 and 2018, the Company capitalized $7.4 million, $15.6 million and $18.7 million of interest related to the construction of new vessels, respectively.
Leases	Leases: The Company adopted Accounting Standards Codification (“ASC”) 842, Leases 1, 2019. ASC 842
Deferred Dry-docking Costs	Deferred Dry-docking Costs: U.S. flagged vessels must meet specified seaworthiness standards established by U.S. Coast Guard rules and classification society rules. These standards require U.S. flagged vessels to undergo between them. However, U.S. flagged vessels that are enrolled in the U.S. Coast Guard’s Underwater Survey in Lieu of Dry-docking (“UWILD”) program are allowed to have their Intermediate Survey dry-docking requirement met with a less costly underwater inspection. Non-U.S. flagged vessels are required to meet applicable classification society rules and their own local standards for seaworthiness, which also mandate vessels to undergo . ​ The Company is responsible for maintaining its vessels in compliance with U.S. and international standards. As costs associated with dry-docking inspections provide future economic benefits to the Company through continued operation of the vessels, the costs are deferred and amortized until the scheduled date of the next required dry-docking, which is usually over a two period. Amortization of deferred dry-docking costs are charged to operating expenses of the Ocean Transportation segment in the Consolidated Statements of Income and Comprehensive Income. Routine vessel maintenance and repairs are charged to expense as incurred.
Goodwill and Intangible Assets	Goodwill and Intangible Assets: Goodwill and intangible assets arise as a result of acquisitions made by the Company (see Note 6). Intangible assets consist of customer relationships which are being amortized using the straight-line method over the expected useful lives ranging up to 21 years , and a trade name that has an indefinite life. ​
Impairment Evaluation of Long-Lived Assets, Intangible Assets and Goodwill	Impairment Evaluation of Long-Lived Assets, Intangible Assets and Goodwill : The Company evaluates its long-lived assets, intangible assets and goodwill for possible impairment in the fourth quarter, or whenever events or changes in circumstances indicate that it is more likely than not that the fair value is less than its carrying amount. The Company has reporting units within the Ocean Transportation and Logistics reportable segments. ​ Long-lived assets and finite-lived intangible assets are grouped at the lowest level reporting unit for which identifiable cash flows are available. In evaluating for impairment, the estimated future undiscounted cash flows generated by each of these asset groups are compared with the carrying value recorded for each asset group to determine if its carrying value is recoverable. If this review determines that the amount recorded will not be recovered, the amount recorded for the asset group is reduced to its estimated fair value. No impairment charges of long-lived assets and finite-lived intangible assets were recorded for the years ended December 31, 2020, 2019 and 2018. ​ Indefinite-life intangible assets and goodwill are grouped at the lowest level reporting unit for which identifiable cash flows are available. In estimating the fair value of a reporting unit, the Company uses a combination of a discounted cash flow model and fair value based on market multiples of earnings before interest, taxes, depreciation and amortization. Based upon the Company’s evaluation of its indefinite-life intangible assets and goodwill for impairment, the Company determined that the fair value of each reporting unit exceeds book value. No impairment charges of indefinite-life intangible assets and goodwill were recorded for the years ended December 31, 2020, 2019 and 2018.
Impairment Evaluation of SSAT	Impairment Evaluation of SSAT: The Company’s investment in SSAT, a related party, is evaluated for impairment whenever there is evidence of impairment during the reporting period. If any impairment is identified, the Company evaluates if the decrease in the fair value of the investment below its carrying value is other-than-temporary. No impairment was identified during the years ended December 31, 2020, 2019 and 2018.
Other liabilities	Other Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, Other Liabilities (in millions) 2020 2019 Payroll and vacation ​ $ 29.2 $ 28.5 ​ Employee incentives and other ​ ​ 25.9 ​ ​ 14.7 ​ Multi-employer withdrawal liabilities - short term (see Note 12) ​ ​ 10.6 ​ ​ 10.8 ​ Income tax liabilities ​ ​ 11.7 ​ ​ 2.3 ​ Insurance reserves and other related liabilities - short term ​ ​ 7.0 ​ ​ 12.6 ​ Deferred revenues ​ ​ 4.2 ​ ​ 6.9 ​ Interest on debt ​ ​ 3.4 ​ ​ 4.9 ​ Pension and post-retirement liabilities - short term (see Note 11) ​ ​ 2.7 ​ ​ 3.1 ​ Other short-term liabilities ​ ​ 2.1 ​ ​ 2.2 ​ Total ​ $ 96.8 $ 86.0 ​
Other long-term liabilities	Other Long-Term Liabilities: Other long-term liabilities consist of the following at December 31, 2020 and 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, Other Long-Term Liabilities (in millions) 2020 2019 Pension and post-retirement liabilities (see Note 11) ​ $ 82.0 ​ $ 73.4 ​ Multi-employer withdrawal liability (see Note 12) ​ ​ 52.8 ​ ​ 54.8 ​ Insurance reserves and other related liabilities ​ ​ 25.4 ​ ​ 26.6 ​ Other long-term liabilities ​ 5.6 ​ 2.6 ​ Total ​ $ 165.8 ​ $ 157.4 ​
Pension and Post-Retirement Plans	Pension and Post-Retirement Plans: The Company is a member of the Pacific Maritime Association (“PMA”) and the Hawaii Stevedoring Industry Committee, which negotiate multi-employer pension plans covering certain shoreside bargaining unit personnel. The Company directly negotiates multi-employer pension plans covering other bargaining unit personnel. Pension costs are accrued in accordance with contribution rates established by the PMA, the parties to a plan or the trustees of a plan. Several trusteed, non-contributory, single-employer defined benefit plans and defined contribution plans cover substantially all other employees. ​ The estimation of the Company’s pension and post-retirement benefit expenses and liabilities requires that the Company make various assumptions. These assumptions include factors such as discount rates, expected long-term rates of return on pension plan assets, salary growth, health care cost trend rates, inflation, retirement rates, mortality rates, and expected contributions. Actual results that differ from the assumptions made could materially affect the Company’s financial condition or its future operating results. Additional information about the Company’s pension and post-retirement plans is included in Note 11.
Insurance Related Liabilities	Insurance Related Liabilities: The Company is uninsured for certain risks but when feasible, many of these risks are mitigated by insurance. The Company purchases insurance with deductibles or self-insured retentions. Such insurance includes, but is not limited to, employee health, workers’ compensation, marine liability, cybersecurity, auto liability and physical damage to property and equipment. For certain risks, the Company elects to not purchase insurance because of the excessive cost of insurance or the perceived remoteness of the risk. In addition, the Company retains all risk of loss that exceeds the limits of the Company’s insurance policies, or for other risks where insurance is not commercially available. ​ When estimating its reserves for retained risks and related liabilities, the Company considers a number of factors, including historical claims experience, demographic factors, current trends, and analyses provided by independent third-parties. Periodically, management reviews its assumptions and estimates used to determine the adequacy of the Company’s reserves for retained risks and other related liabilities.
Recognition of Revenues and Expenses	Recognition of Revenues and Expenses: Revenue in the Company’s Consolidated Financial Statements is presented net of elimination of intercompany transactions. The following is a description of the Company’s principal revenue generating activities by segment, and the Company’s revenue recognition policy for each activity for the periods presented: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, Ocean Transportation (in millions) (1) ​ 2020 ​ 2019 ​ 2018 Ocean Transportation services ​ $ 1,821.7 ​ $ 1,625.8 ​ $ 1,599.3 Terminal and other related services ​ ​ 19.1 ​ ​ 24.8 ​ ​ 23.0 Fuel sales ​ ​ 7.3 ​ ​ 10.1 ​ ​ 12.2 Vessel management and related services ​ ​ 5.8 ​ ​ 5.9 ​ ​ 6.8 Total ​ $ 1,853.9 ​ $ 1,666.6 ​ $ 1,641.3 (1) Ocean Transportation revenue transactions are primarily denominated in U.S. dollars except for less than 3 percent of Ocean Transportation services revenue and fuel sales revenue categories which are denominated in foreign currencies. ​ ◾ Ocean Transportation services revenue is recognized ratably over the duration of a voyage based on the relative transit time completed in each reporting period. Vessel operating costs and other ocean transportation operating costs, such as terminal operating overhead and selling, general and administrative expenses, are charged to operating costs as incurred. ◾ Terminal and other related services revenue is recognized as the services are performed. Related costs are recognized as incurred. ◾ Fuel sales revenue and related costs are recognized when the Company has completed delivery of the product to the customer in accordance with the terms and conditions of the contract. ◾ Vessel management and related services revenue is recognized in proportion to the services completed. Related costs are recognized as incurred. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, Logistics (in millions) (1) ​ 2020 ​ 2019 (2) ​ 2018 (2) Transportation Brokerage and Freight Forwarding services ​ $ 477.0 ​ $ 489.0 ​ $ 532.5 Warehouse and distribution services ​ ​ 36.2 ​ ​ 34.1 ​ ​ 33.8 Supply chain management and other services ​ 16.2 ​ 13.4 ​ 15.2 Total ​ $ 529.4 ​ $ 536.5 ​ $ 581.5 (1) Logistics revenue transactions are primarily denominated in U.S. dollars except for approximately 3 percent of transportation brokerage and freight forwarding services revenue, and supply chain management and other services revenue categories which are denominated in foreign currencies. (2) The Company has reclassified $15.8 million and $16.6 million from transportation brokerage and freight forwarding services to warehouse and distribution services, and supply chain management and other services for the years ended December 31, 2019 and 2018 , respectively, to be consistent with its current period presentation. There was no change in total Logistics revenue for the years ended December 31, 2019 and 2018. ​ ◾ Transportation Brokerage and Freight Forwarding services revenue consists of amounts billed to customers for services provided. The primary costs include third-party purchased transportation services, agent commissions, labor and equipment. Revenue and the related purchased third-party transportation costs are recognized over the duration of a delivery based upon the relative transit time completed in each reporting period. Labor, agent commissions, and other operating costs are expensed as incurred. The Company reports revenue on a gross basis as the Company serves as the principal in these transactions because it is responsible for fulfilling the contractual arrangements with the customer and has latitude in establishing prices. ◾ Warehousing and distribution services revenue consist of amounts billed to customers for storage, handling, and value-added packaging of customer merchandise. Storage revenue is recognized in the month the service is provided to the customer. Storage related costs are recognized as incurred. Other warehousing and distribution services revenue and related costs are recognized in proportion to the services performed. ◾ Supply chain management and other services revenue, and related costs are recognized in proportion to the services performed. ​ The Company generally invoices its customers at the commencement of the voyage or the transportation service being provided, or as other services are being performed. Revenue is deferred when services are invoiced in advance to the customer. The Company’s receivables are classified as short-term as collection terms are for periods of less than one year. The Company expenses sales commissions and contract acquisition costs as incurred because the amounts are generally immaterial. These expenses are included in selling, general and administration expenses in the Consolidated Statements of Income and Comprehensive Income.
Customer Concentration	Customer Concentration: The Ocean Transportation segment serves customers in numerous industries and carries a wide variety of cargo, mitigating its dependence upon any single customer or single type of cargo. In 2020, 2019 and 2018, the percent of Ocean Transportation revenue, respectively. ​ The Logistics segment serves customers in numerous industries and geographical locations. In 2020, 2019 and 2018, the percent of Logistics revenue, respectively.
Dividends	Dividends:
Share-Based Compensation	Share-Based Compensation: The Company records compensation expense for all share-based awards made to employees and directors. The Company’s various stock-based compensation plans are more fully described in Note 15.
Income Taxes	Income Taxes: The estimate of the Company’s income tax expense requires the Company to make various estimates and judgments. These estimates and judgments are applied in the calculation of taxable income, tax credits, tax benefits and deductions, and in the calculation of certain deferred tax assets and liabilities, which arise from differences in the timing of recognition of revenue, costs and expenses for tax purposes. Deferred tax assets and liabilities are adjusted to the extent necessary to reflect tax rates expected to be in effect when the temporary differences reverse. ​ The Company records a valuation allowance if, based on the weight of available evidence, management believes that it is more likely than not that some portion or all of a recorded deferred tax asset would not be realized in future periods. The Company’s income taxes are more fully described in Note 10.
Rounding	Rounding: Amounts in the Consolidated Financial Statements and Notes to the Consolidated Financial Statements are rounded to millions, except for per share calculations and percentages which were determined based on amounts before rounding. Accordingly, a recalculation of some per-share amounts and percentages, if based on the reported data, may be slightly different.
New Accounting Pronouncements	New Accounting Pronouncements : ​ Measurement of Credit Losses on Financial Instruments : In June 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016- 13 which amends the current approach to estimate credit losses on certain financial assets, including trade and other receivables, available-for-sale securities and other financial instruments. ASU 2016- 13 requires entities to establish a valuation allowance for the expected lifetime losses of certain financial instruments. Subsequent changes in the valuation allowance are recorded in current earnings and reversal of previous losses is permitted. The new standard was effective for interim and annual periods beginning on or after December 15, 2019. ​ The Company adopted ASU 2016- 13 effective January 1, 2020 using the modified retrospective approach. Upon adoption, the Company included an evaluation of expected future credit losses as part of its estimate for determining the allowance for doubtful accounts. The impact of this change was not material to the Company’s allowance for doubtful accounts receivable in the Consolidated Financial Statements. ​ Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract (“ASU 2018-15”): In August 2018, FASB issued ASU 2018-15 which aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing costs incurred to develop or obtain internal-use software. The Company adopted ASU 2018-15 on a prospective basis effective January 1, 2020. During the year ended December 31, 2020, the Company capitalized costs of $2.4 million related to cloud computing arrangements and which were included in other long-term assets on the Company’s Consolidated Balance Sheets as of December 31, 2020.

SIGNIFICANT ACCOUNTING POLICI_3

SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2020
Schedule of changes in the allowance for doubtful accounts receivable	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at ​ Write-offs Balance at Year (in millions) Beginning of Year Expense (1) and Other End of Year 2020 ​ $ 4.3 ​ $ 2.9 ​ $ (0.9) ​ $ 6.3 ​ 2019 ​ $ 4.8 ​ $ 0.6 ​ $ (1.1) ​ $ 4.3 ​ 2018 ​ $ 4.6 ​ $ 0.8 ​ $ (0.6) ​ $ 4.8 ​ (1) Expense is shown net of amounts recovered from previously reserved doubtful accounts.
Schedule of prepaid expenses and other assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, Prepaid Expenses and Other Assets (in millions) 2020 2019 Prepaid fuel ​ $ 10.8 ​ $ 13.7 ​ Prepaid insurance and insurance related receivables ​ 7.5 ​ 13.4 ​ Prepaid operating expenses ​ ​ 5.4 ​ ​ 5.7 ​ Restricted cash - vessel construction obligations ​ ​ 5.3 ​ ​ 7.2 ​ Income tax receivables ​ ​ 0.3 ​ ​ 12.8 ​ Other ​ 8.8 ​ 9.7 ​ Total ​ $ 38.1 ​ $ 62.5 ​
Schedule of other long-term assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, Other Long-Term Assets (in millions) 2020 2019 Vessel and equipment spare parts ​ $ 11.5 ​ $ 12.4 ​ Insurance related receivables ​ ​ 10.5 ​ ​ 10.6 ​ Deferred loan fees ​ 2.7 ​ 2.1 ​ Cloud computing software costs ​ 2.4 ​ — ​ Income tax receivables ​ ​ 2.1 ​ ​ 11.5 ​ Other ​ ​ 3.8 ​ ​ 1.2 ​ Total ​ $ 33.0 ​ $ 37.8 ​
Schedule of estimated useful lives of property and equipment	​ ​ ​ ​ ​ Classification Life Vessels 40 years ​ Machinery and equipment 30 years ​ Terminal facilities 35 years ​
Schedule other liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, Other Liabilities (in millions) 2020 2019 Payroll and vacation ​ $ 29.2 $ 28.5 ​ Employee incentives and other ​ ​ 25.9 ​ ​ 14.7 ​ Multi-employer withdrawal liabilities - short term (see Note 12) ​ ​ 10.6 ​ ​ 10.8 ​ Income tax liabilities ​ ​ 11.7 ​ ​ 2.3 ​ Insurance reserves and other related liabilities - short term ​ ​ 7.0 ​ ​ 12.6 ​ Deferred revenues ​ ​ 4.2 ​ ​ 6.9 ​ Interest on debt ​ ​ 3.4 ​ ​ 4.9 ​ Pension and post-retirement liabilities - short term (see Note 11) ​ ​ 2.7 ​ ​ 3.1 ​ Other short-term liabilities ​ ​ 2.1 ​ ​ 2.2 ​ Total ​ $ 96.8 $ 86.0 ​
Schedule of other long-term liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, Other Long-Term Liabilities (in millions) 2020 2019 Pension and post-retirement liabilities (see Note 11) ​ $ 82.0 ​ $ 73.4 ​ Multi-employer withdrawal liability (see Note 12) ​ ​ 52.8 ​ ​ 54.8 ​ Insurance reserves and other related liabilities ​ ​ 25.4 ​ ​ 26.6 ​ Other long-term liabilities ​ 5.6 ​ 2.6 ​ Total ​ $ 165.8 ​ $ 157.4 ​
Ocean Transportation
Schedule of principal revenue generating activities by segment	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, Ocean Transportation (in millions) (1) ​ 2020 ​ 2019 ​ 2018 Ocean Transportation services ​ $ 1,821.7 ​ $ 1,625.8 ​ $ 1,599.3 Terminal and other related services ​ ​ 19.1 ​ ​ 24.8 ​ ​ 23.0 Fuel sales ​ ​ 7.3 ​ ​ 10.1 ​ ​ 12.2 Vessel management and related services ​ ​ 5.8 ​ ​ 5.9 ​ ​ 6.8 Total ​ $ 1,853.9 ​ $ 1,666.6 ​ $ 1,641.3 (1) Ocean Transportation revenue transactions are primarily denominated in U.S. dollars except for less than 3 percent of Ocean Transportation services revenue and fuel sales revenue categories which are denominated in foreign currencies. ​ ◾ Ocean Transportation services revenue is recognized ratably over the duration of a voyage based on the relative transit time completed in each reporting period. Vessel operating costs and other ocean transportation operating costs, such as terminal operating overhead and selling, general and administrative expenses, are charged to operating costs as incurred. ◾ Terminal and other related services revenue is recognized as the services are performed. Related costs are recognized as incurred. ◾ Fuel sales revenue and related costs are recognized when the Company has completed delivery of the product to the customer in accordance with the terms and conditions of the contract. ◾ Vessel management and related services revenue is recognized in proportion to the services completed. Related costs are recognized as incurred.
Logistics
Schedule of principal revenue generating activities by segment	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, Logistics (in millions) (1) ​ 2020 ​ 2019 (2) ​ 2018 (2) Transportation Brokerage and Freight Forwarding services ​ $ 477.0 ​ $ 489.0 ​ $ 532.5 Warehouse and distribution services ​ ​ 36.2 ​ ​ 34.1 ​ ​ 33.8 Supply chain management and other services ​ 16.2 ​ 13.4 ​ 15.2 Total ​ $ 529.4 ​ $ 536.5 ​ $ 581.5 (1) Logistics revenue transactions are primarily denominated in U.S. dollars except for approximately 3 percent of transportation brokerage and freight forwarding services revenue, and supply chain management and other services revenue categories which are denominated in foreign currencies. (2) The Company has reclassified $15.8 million and $16.6 million from transportation brokerage and freight forwarding services to warehouse and distribution services, and supply chain management and other services for the years ended December 31, 2019 and 2018 , respectively, to be consistent with its current period presentation. There was no change in total Logistics revenue for the years ended December 31, 2019 and 2018. ​ ◾ Transportation Brokerage and Freight Forwarding services revenue consists of amounts billed to customers for services provided. The primary costs include third-party purchased transportation services, agent commissions, labor and equipment. Revenue and the related purchased third-party transportation costs are recognized over the duration of a delivery based upon the relative transit time completed in each reporting period. Labor, agent commissions, and other operating costs are expensed as incurred. The Company reports revenue on a gross basis as the Company serves as the principal in these transactions because it is responsible for fulfilling the contractual arrangements with the customer and has latitude in establishing prices. ◾ Warehousing and distribution services revenue consist of amounts billed to customers for storage, handling, and value-added packaging of customer merchandise. Storage revenue is recognized in the month the service is provided to the customer. Storage related costs are recognized as incurred. Other warehousing and distribution services revenue and related costs are recognized in proportion to the services performed. ◾ Supply chain management and other services revenue, and related costs are recognized in proportion to the services performed.

REPORTABLE SEGMENTS (Tables)

REPORTABLE SEGMENTS (Tables)	12 Months Ended
	Dec. 31, 2020
REPORTABLE SEGMENTS
Schedule of reportable segment information	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, (In millions) 2020 2019 2018 Operating Revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ Ocean Transportation (1) ​ $ 1,853.9 ​ $ 1,666.6 ​ $ 1,641.3 Logistics (2) ​ 529.4 ​ 536.5 ​ 581.5 Total Operating Revenue ​ $ 2,383.3 ​ $ 2,203.1 ​ $ 2,222.8 Operating Income: ​ ​ ​ ​ ​ ​ ​ ​ ​ Ocean Transportation (3) ​ $ 244.8 ​ $ 90.8 ​ $ 131.1 Logistics ​ 35.5 ​ 38.3 ​ 32.7 Total Operating Income ​ 280.3 ​ 129.1 ​ 163.8 Interest expense, net ​ (27.4) ​ (22.5) ​ (18.7) Other income (expense), net ​ 6.1 ​ 1.2 ​ 2.6 Income before Income Taxes ​ 259.0 ​ 107.8 ​ 147.7 Income taxes ​ (65.9) ​ (25.1) ​ (38.7) Net Income ​ $ 193.1 ​ $ 82.7 ​ $ 109.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Capital Expenditures: ​ ​ ​ ​ ​ ​ ​ ​ ​ Ocean Transportation ​ $ 190.0 ​ $ 294.5 ​ $ 385.4 Logistics ​ 2.3 ​ 15.8 ​ 15.8 Total Capital Expenditures ​ $ 192.3 ​ $ 310.3 ​ $ 401.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Depreciation and Amortization: ​ ​ ​ ​ ​ ​ ​ ​ ​ Ocean Transportation ​ $ 107.4 ​ $ 93.6 ​ $ 87.0 Logistics ​ 7.5 ​ 6.8 ​ 7.4 ​ ​ ​ 114.9 ​ ​ 100.4 ​ ​ 94.4 Deferred dry-docking amortization - Ocean Transportation ​ ​ 25.1 ​ ​ 34.3 ​ ​ 37.4 Total Depreciation and Amortization ​ $ 140.0 ​ $ 134.7 ​ $ 131.8 (1) Ocean Transportation operating revenue excludes inter-segment revenue of $59.1 million, $52.8 million and $51.7 million for the years ended December 31, 2020, 2019 and 2018, respectively. (2) Logistics operating revenue excludes inter-segment revenue of $56.4 million, $49.5 million and $43.7 million for the years ended December 31, 2020, 2019 and 2018, respectively. (3) Ocean Transportation segment information includes $26.3 million, $20.8 million, and $36.8 million of equity in income from the Company’s equity investment in SSAT for the years ended December 31, 2020, 2019 and 2018, respectively. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, (In millions) 2020 2019 Identifiable Assets: ​ ​ ​ ​ ​ ​ Ocean Transportation (1) ​ $ 2,431.1 ​ $ 2,424.5 Logistics ​ 469.5 ​ 420.9 Total Assets ​ $ 2,900.6 ​ $ 2,845.4 (1) The Ocean Transportation segment includes $48.7 million and $76.2 million related to the Company’s equity investment in SSAT as of December 31, 2020 and 2019, respectively.

INVESTMENT IN SSAT (Tables)

INVESTMENT IN SSAT (Tables)	12 Months Ended
	Dec. 31, 2020
INVESTMENT IN SSAT
Schedule of condensed income statement information for SSAT	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, (In millions) 2020 2019 2018 Company's share of net income ​ $ 26.3 ​ $ 20.8 ​ $ 36.8 ​ Distributions received ​ $ 55.4 ​ $ 25.2 ​ $ 42.0 ​
Unaudited condensed financial information for SSAT - Balance Sheet	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ Condensed Balance Sheets (in millions) 2020 2019 Current assets ​ $ 294.3 ​ $ 300.8 ​ Non-current assets ​ 1,249.5 ​ 1,283.0 ​ Total Assets ​ $ 1,543.8 ​ $ 1,583.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ Current liabilities ​ $ 238.2 ​ $ 201.9 ​ Non-current liabilities ​ 1,179.9 ​ 1,179.2 ​ Equity ​ 125.7 ​ 202.7 ​ Total Liabilities and Equity ​ $ 1,543.8 ​ $ 1,583.8 ​ ​
Unaudited financial information for SSAT - Statement of Operating Income and Net Income	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ Condensed Statements of Operating Income and Net Income (in millions) 2020 2019 2018 Operating revenue ​ $ 1,091.6 ​ $ 1,098.3 ​ $ 1,074.2 ​ Operating costs and expenses ​ 1,003.2 ​ 1,035.3 ​ 963.7 ​ Operating income ​ 88.4 ​ 63.0 ​ 110.5 ​ Net Income (1) ​ $ 76.6 ​ $ 57.2 ​ $ 104.9 ​ (1) Includes earnings from equity method investments held by SSAT less earnings allocated to non-controlling interests.

PROPERTY AND EQUIPMENT (Tables)

PROPERTY AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2020
PROPERTY AND EQUIPMENT
Schedule of property and equipment	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2020 ​ As of December 31, 2019 ​ ​ ​ Accumulated ​ ​ ​ Accumulated ​ (In millions) ​ Cost ​ Depreciation ​ Net Book Value ​ Cost ​ Depreciation ​ Net Book Value Vessels ​ $ 2,191.6 ​ $ 785.5 ​ $ 1,406.1 ​ ​ $ 1,653.5 ​ $ 818.5 ​ $ 835.0 ​ Containers and equipment ​ 572.3 ​ ​ 391.8 ​ 180.5 ​ ​ 544.5 ​ 378.8 ​ 165.7 ​ Terminal facilities and other property ​ 119.8 ​ ​ 45.1 ​ 74.7 ​ ​ 114.4 ​ 41.3 ​ 73.1 ​ Vessel construction in progress ​ ​ — ​ ​ — ​ ​ — ​ ​ ​ 488.9 ​ ​ — ​ ​ 488.9 ​ Other construction in progress ​ 28.6 ​ ​ — ​ 28.6 ​ ​ 35.4 ​ — ​ 35.4 ​ Total ​ $ 2,912.3 ​ $ 1,222.4 ​ $ 1,689.9 ​ ​ $ 2,836.7 ​ $ 1,238.6 ​ $ 1,598.1 ​
Schedule of depreciation expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, (In millions) 2020 2019 2018 Depreciation expense ​ $ 97.1 ​ $ 86.3 ​ $ 80.5 ​

GOODWILL AND INTANGIBLES ASSE_2

GOODWILL AND INTANGIBLES ASSETS (Tables)	12 Months Ended
	Dec. 31, 2020
GOODWILL AND INTANGIBLES ASSETS
Schedule of goodwill	Goodwill by segment as of December 31, 2020 and 2019 consists of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ocean ​ ​ ​ ​ ​ ​ (In millions) Transportation Logistics Total Goodwill ​ $ 222.6 ​ $ 105.2 ​ $ 327.8
Schedule of intangible assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2020 ​ As of December 31, 2019 ​ ​ Gross ​ Accumulated ​ ​ ​ ​ Gross ​ Accumulated ​ ​ ​ (In millions) Amount Amortization Net Book Value Amount Amortization Net Book Value Ocean Transportation - Customer relationships ​ $ 140.6 ​ $ 37.9 ​ $ 102.7 ​ ​ $ 140.6 ​ $ 31.2 ​ $ 109.4 ​ Logistics: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Customer relationships ​ ​ 90.1 ​ ​ 28.1 ​ ​ 62.0 ​ ​ ​ 90.1 ​ ​ 23.9 ​ ​ 66.2 ​ Trade name ​ 27.3 ​ ​ — ​ ​ 27.3 ​ ​ 27.3 ​ ​ — ​ ​ 27.3 ​ Total Logistics ​ 117.4 ​ ​ 28.1 ​ ​ 89.3 ​ ​ 117.4 ​ ​ 23.9 ​ ​ 93.5 ​ Total ​ $ 258.0 ​ $ 66.0 ​ $ 192.0 ​ ​ $ 258.0 ​ $ 55.1 ​ $ 202.9 ​
Schedule of intangible asset related amortization expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, (In millions) 2020 2019 2018 Amortization expense ​ $ 10.9 ​ $ 11.1 ​ $ 11.2 ​
Schedule of estimated amortization expenses related to intangible assets	As of December 31, 2020, estimated amortization expense related to customer relationship intangible assets during the next five years and thereafter is as follows: ​ ​ ​ ​ ​ ​ ​ Customer ​ Year (in millions) ​ Relationships 2021 ​ $ 10.9 ​ 2022 ​ 10.7 ​ 2023 ​ 10.7 ​ 2024 ​ 10.7 ​ 2025 ​ 10.7 ​ Thereafter ​ 111.0 ​ Total ​ $ 164.7 ​

DEBT (Tables)

DEBT (Tables)	12 Months Ended
	Dec. 31, 2020
DEBT
Schedule of debt	At December 31, 2020 and 2019, the Company’s debt consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ (In millions) 2020 2019 Private Placement Term Loans: ​ ​ ​ ​ ​ ​ ​ 5.79 %, payable through 2020 ​ $ — ​ $ 3.5 ​ 3.66 %, payable through 2023 ​ 22.8 ​ 31.9 ​ 4.16 %, payable through 2027 ​ 34.0 ​ 39.3 ​ 3.37 %, payable through 2027 ​ ​ 75.0 ​ ​ 75.0 ​ 3.14 %, payable through 2031 ​ ​ 169.6 ​ ​ 188.0 ​ 4.31 %, payable through 2032 ​ 27.9 ​ 30.3 ​ 4.35 %, payable through 2044 ​ ​ — ​ ​ 100.0 ​ 3.92 %, payable through 2045 ​ ​ — ​ ​ 69.5 ​ Title XI Debt: ​ ​ ​ ​ ​ ​ ​ 5.34 %, payable through 2028 ​ 17.6 ​ 19.8 ​ 5.27 %, payable through 2029 ​ 19.8 ​ 22.0 ​ 1.22 %, payable through 2043 ​ ​ 182.0 ​ ​ — ​ 1.35 %, payable through 2044 ​ ​ 139.6 ​ ​ — ​ Revolving credit facility, maturity date of June 29, 2022 ​ 71.8 ​ 379.1 ​ Total Debt ​ 760.1 ​ 958.4 ​ Less: Current portion ​ (59.2) ​ (48.4) ​ Total Long-term Debt ​ ​ 700.9 ​ ​ 910.0 ​ Less: Deferred loan fees ​ ​ (15.3) ​ ​ — ​ Total Long-term Debt, net of deferred loan fees ​ $ 685.6 ​ $ 910.0 ​
Schedule of maturities of debt	​ ​ ​ ​ ​ ​ ​ As of Year (in millions) December 31, 2020 2021 ​ $ 59.2 2022 ​ 136.8 2023 ​ 60.4 2024 ​ 51.7 2025 ​ 51.7 Thereafter ​ 400.3 Total Debt ​ $ 760.1
Schedule of deferred loan fees	​ ​ ​ ​ ​ Deferred Loan Fees (in millions) Amount Deferred financing costs related to Title XI bonds and private placement debt amendments ​ $ 16.5 Deferred fees expensed related to the redemption of private placement debt ​ ​ (0.3) Amortization expense for the year ended December 31, 2020 ​ (0.9) Balance at December 31, 2020 ​ $ 15.3
Schedule of estimated amortization expense relating to deferred laon fees	​ ​ ​ ​ ​ Year (in millions) Amount 2021 ​ $ 1.5 2022 ​ 1.2 2023 ​ 1.1 2024 ​ 1.1 2025 ​ 1.0 Thereafter ​ 9.4 Total amortization expense of deferred loan fees ​ $ 15.3

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Dec. 31, 2020
LEASES
Summary of underlying asset class and maximum terms	​ ​ ​ ​ Lease Type: Term Real estate and terminal leases 65 years Vessel charter leases 10 years Operations equipment and other leases 8 years
Summary of lease cost	Components of Lease Cost: Components of lease cost recorded in the Company’s Consolidated Statement of Income and Comprehensive Income for the years ended December 31, 2020 and 2019 consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended ​ ​ December 31, (In millions) 2020 ​ 2019 Operating lease cost ​ $ 83.1 ​ $ 71.4 Short-term lease cost ​ 10.6 ​ 5.9 Variable lease cost ​ 0.8 ​ 0.4 Total lease cost ​ $ 94.5 ​ $ 77.7 ​ Other Lease Information: Other information related to the Company’s operating leases for the years ended December 31, 2020 and 2019 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended ​ ​ December 31, (In millions) 2020 ​ 2019 Cash paid for amounts included in operating lease liabilities ​ $ 83.6 ​ $ 71.3 Right of use assets obtained in the exchange for new operating lease liabilities ​ $ 70.1 ​ $ 65.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ ​ 2020 2019 Weighted average remaining operating lease term ​ ​ 7.0 years ​ ​ 7.5 years Weighted average incremental borrowing rate ​ ​ 3.7% ​ ​ 4.2% ​
Summary of maturities of operating lease liabilities at December 31, 2020	​ ​ ​ ​ ​ ​ As of Year (in millions) December 31, 2020 2021 ​ $ 80.5 2022 ​ 53.2 2023 ​ 47.3 2024 ​ 31.8 2025 ​ 23.9 Thereafter ​ 65.6 Total lease payments ​ ​ 302.3 Less: Interest ​ ​ (43.0) Present value of operating lease liabilities ​ ​ 259.3 Less: Short-term portion ​ ​ (72.4) Long-term operating lease liabilities ​ $ 186.9

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2020
INCOME TAXES
Schedule of income tax expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, (In millions) 2020 2019 2018 Current: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Federal ​ $ — ​ $ 0.2 ​ $ 1.5 ​ State ​ 8.7 ​ 3.2 ​ 2.1 ​ Foreign ​ ​ 1.4 ​ ​ 1.3 ​ ​ 0.9 ​ Discrete adjustments related to the Tax Act (1) ​ ​ — ​ ​ (2.9) ​ ​ 2.9 ​ Total ​ 10.1 ​ 1.8 ​ 7.4 ​ Deferred: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferred tax expense ​ ​ 55.8 ​ ​ 23.3 ​ ​ 31.3 ​ Total income taxes ​ $ 65.9 ​ $ 25.1 ​ $ 38.7 ​ (1) Current income taxes for the years ended December 31, 2019 and 2018 include a non-cash income tax benefit of $2.9 million and a non-cash income tax expense of $2.9 million, respectively, which relates to discrete adjustments as a result of applying the provisions of the Tax Act. ​
Schedule of effective income tax rate	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ 2020 2019 2018 Computed federal income tax expense 21.0 % 21.0 % 21.0 % State income tax 3.5 % 4.1 % 3.4 % Valuation allowance (0.2) % (0.3) % (0.7) % Foreign taxes 0.6 % 1.2 % 0.6 % Remeasurement and discrete adjustments related to the Tax Act (1) — % (2.7) % 2.0 % Share-based payments (0.5) % (0.1) % 0.1 % Other — net 1.0 % 0.1 % (0.2) % Effective income tax rate 25.4 % 23.3 % 26.2 % (1) Effective income tax rate for the years ended December 31, 2019 and 2018 includes the impact of a non-cash income tax benefit of $2.9 million, or 2.7 percent, and a non-cash income tax expense of $2.9 million, or 2.0 percent, respectively, which related to certain discrete adjustments as a result of applying the provisions of the Tax Act.
Schedule of tax effects of temporary differences	​ The tax effects of temporary differences that gave rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, 2020 and 2019, were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, (In millions) 2020 2019 Deferred tax assets: ​ ​ ​ ​ ​ ​ ​ Operating lease liabilities ​ $ 63.5 ​ $ 63.1 ​ Pension and post-retirement plans ​ ​ 21.7 ​ ​ 19.2 ​ Multi-employer withdrawal liabilities ​ ​ 15.6 ​ ​ 16.1 ​ Federal net operating losses ​ ​ 0.9 ​ ​ 14.3 ​ State net operating losses ​ ​ 7.5 ​ ​ 7.3 ​ U.S. State alternative minimum tax credits ​ 4.4 ​ 6.7 ​ Insurance reserves ​ 5.3 ​ 5.9 ​ Deferred compensation ​ 8.2 ​ ​ 5.8 ​ Other ​ 10.4 ​ 5.9 ​ Total deferred tax assets ​ 137.5 ​ 144.3 ​ Valuation allowance ​ ​ (10.0) ​ ​ (10.6) ​ Total deferred tax assets, net of valuation allowance ​ ​ 127.5 ​ ​ 133.7 ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferred tax liabilities: ​ ​ ​ ​ ​ ​ ​ Basis differences for property and equipment ​ 372.4 ​ 319.2 ​ Operating lease right of use assets ​ 61.5 ​ 61.1 ​ Intangibles ​ ​ 40.5 ​ ​ 39.7 ​ Lease financing ​ ​ 22.0 ​ ​ 23.7 ​ Capital Construction Fund ​ 6.7 ​ ​ 12.5 ​ Investment in SSAT ​ 7.4 ​ 7.4 ​ Other ​ ​ 6.6 ​ ​ 7.7 ​ Total deferred tax liabilities ​ 517.1 ​ 471.3 ​ Deferred tax liability, net ​ $ 389.6 ​ $ 337.6 ​
Schedule of company's net operating losses ("NOLs") and tax credit carryforwards	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (In millions) ​ Expiration Date 2020 2019 U.S. Federal income tax NOLs ​ Various dates beginning in 2027 ​ $ 7.6 ​ $ 71.2 U.S. State income tax NOLs (1) ​ Various dates beginning in 2032 ​ $ 185.9 ​ $ 184.5 U.S. State alternative minimum tax credit ​ No expiration date ​ $ 4.0 ​ $ 6.7 Foreign income tax NOLs ​ No expiration date ​ $ 11.9 ​ $ 14.0 (1) The Company does not expect to benefit from $157.9 million and $157.9 million of U.S. State income tax NOLs as of December 31, 2020 and 2019, respectively. ​
Reconciliation of unrecognized tax benefits	​ ​ ​ ​ ​ ​ Unrecognized Tax Benefits (in millions) Amount Balance at December 31, 2017 ​ $ 15.9 ​ Changes in tax positions of prior years, net ​ (0.3) ​ Reductions for lapse of statute of limitations ​ ​ (0.5) ​ Balance at December 31, 2018 ​ 15.1 ​ Changes in tax positions of prior years, net ​ 2.1 ​ Reductions for lapse of statute of limitations ​ ​ (0.8) ​ Balance at December 31, 2019 ​ 16.4 ​ Changes in tax positions of prior years, net ​ 2.1 ​ Reductions for lapse of statute of limitations ​ ​ (0.2) ​ Balance at December 31, 2020 ​ $ 18.3 ​

PENSION AND POST-RETIREMENT P_2

PENSION AND POST-RETIREMENT PLANS (Tables)	12 Months Ended
	Dec. 31, 2020
PENSION AND POST-RETIREMENT PLANS
Schedule of the Company's target and actual asset allocations	​ ​ ​ ​ ​ ​ ​ ​ ​ Asset Categories Target 2020 2019 Domestic equity securities 53 % 60 % 59 % International equity securities 15 % 17 % 17 % Debt securities 22 % 17 % 17 % Real estate 5 % 5 % 6 % Other and cash 5 % 1 % 1 % Total 100 % 100 % 100 %
Schedule of the Company's actual return on plan assets	​ ​ ​ ​ ​ Actual Return on Plan Assets Returns One-year return 12.0 % Three-year return 8.7 % Five-year return 9.8 % Long-term average return (since plan inception in 1989) 8.5 %
Schedule of the fair values of the Company's pension plan assets, by asset category	The fair values of the Company’s pension plan assets at December 31, 2020 and 2019 by asset category were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at December 31, 2020 ​ ​ ​ Quoted Prices in Significant Significant ​ ​ ​ ​ ​ Active Markets ​ Observable ​ Unobservable Asset Category (in millions) ​ Total ​ (Level 1) ​ Inputs (Level 2) ​ Inputs (Level 3) Cash ​ $ 3.8 ​ $ 3.8 ​ $ — ​ $ — ​ Equity securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. large-cap ​ 71.3 ​ 28.9 ​ 42.4 ​ — ​ U.S. mid- and small-cap ​ 54.3 ​ 36.2 ​ 18.1 ​ — ​ International large-cap ​ 7.0 ​ — ​ 7.0 ​ — ​ Fixed income securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasuries ​ 12.0 ​ — ​ 12.0 ​ — ​ Investment grade U.S. corporate bonds ​ ​ 22.5 ​ — ​ 22.5 ​ — ​ Total ​ ​ 170.9 ​ $ 68.9 ​ $ 102.0 ​ $ — ​ Investment measured at NAV (1) ​ ​ 41.9 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total plan assets ​ $ 212.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at December 31, 2019 ​ ​ ​ Quoted Prices in Significant Significant ​ ​ ​ ​ ​ Active Markets ​ Observable ​ Unobservable Asset Category (in millions) ​ Total ​ (Level 1) ​ Inputs (Level 2) ​ Inputs (Level 3) Cash ​ $ 6.3 ​ $ 6.3 ​ $ — ​ $ — ​ Equity securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. large-cap ​ 62.4 ​ 23.7 ​ 38.7 ​ — ​ U.S. mid- and small-cap ​ 49.6 ​ 33.9 ​ 15.7 ​ — ​ International large-cap ​ 6.6 ​ — ​ 6.6 ​ — ​ Fixed income securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. Treasuries ​ 14.1 ​ — ​ 14.1 ​ — ​ Investment grade U.S. corporate bonds ​ 18.2 ​ — ​ 18.2 ​ — ​ High-yield U.S. corporate bonds ​ 0.1 ​ — ​ 0.1 ​ — ​ Total ​ ​ 157.3 ​ $ 63.9 ​ $ 93.4 ​ $ — ​ Investment measured at NAV (1) ​ ​ 37.5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total plan assets ​ $ 194.8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Real estate funds for which fair value is measured using the NAV per share as a practical expedient are not leveled within the fair value hierarchy and are included as a reconciling item to total plan assets.
Schedule of change in benefit obligation and plan assets	The status of the funded qualified defined benefit pension plans and the unfunded post-retirement benefit plans at December 31, 2020 and 2019 are shown below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Post-retirement ​ ​ Pension Benefits ​ Benefits ​ ​ December 31, ​ December 31, ​ (In millions) 2020 2019 2020 2019 Change in Benefit Obligation: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Benefit obligation at beginning of year ​ $ 239.9 ​ $ 217.4 ​ $ 26.0 ​ $ 22.2 ​ Service cost ​ 5.1 ​ 4.7 ​ 0.5 ​ 0.4 ​ Interest cost ​ 7.9 ​ 9.3 ​ 0.8 ​ 0.9 ​ Plan participants’ contributions ​ — ​ — ​ 0.8 ​ 0.8 ​ Actuarial loss ​ 23.9 ​ 22.2 ​ 2.7 ​ 3.4 ​ Benefits paid, net of subsidies received ​ (12.5) ​ (12.2) ​ (1.7) ​ (1.7) ​ Expenses paid ​ (1.2) ​ (1.5) ​ — ​ — ​ Benefit obligation at end of year ​ ​ 263.1 ​ ​ 239.9 ​ ​ 29.1 ​ ​ 26.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Change in Plan Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value of plan assets at beginning of year ​ ​ 194.8 ​ ​ 162.2 ​ ​ — ​ ​ — ​ Actual return on plan assets ​ 22.7 ​ 36.3 ​ — ​ — ​ Plan participants’ contributions ​ — ​ — ​ 0.8 ​ 0.8 ​ Employer contributions ​ 9.0 ​ 10.0 ​ 0.9 ​ 0.9 ​ Benefits paid, net of subsidies received ​ (12.5) ​ (12.2) ​ (1.7) ​ (1.7) ​ Expenses paid ​ (1.2) ​ (1.5) ​ — ​ — ​ Fair value of plan assets at end of year ​ 212.8 ​ 194.8 ​ — ​ — ​ Funded Status and Recognized Liability ​ $ (50.3) ​ $ (45.1) ​ $ (29.1) ​ $ (26.0) ​
Schedule of amounts recognized on the consolidated balance sheets and in accumulated other comprehensive loss	Qualified pension and post-retirement benefits plans liabilities recognized in the Consolidated Balance Sheets and expenses recognized in accumulated other comprehensive income (loss) at December 31, 2020 and 2019 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Post-retirement ​ ​ Pension Benefits ​ Benefits ​ ​ December 31, ​ December 31, ​ (In millions) 2020 2019 2020 2019 Non-current assets ​ $ 1.0 ​ $ 1.0 ​ $ — ​ $ — ​ Current liabilities ​ ​ — ​ ​ — ​ ​ (1.0) ​ ​ (1.0) ​ Non-current liabilities, net ​ (51.3) ​ (46.1) ​ (28.1) ​ (25.0) ​ Total ​ $ (50.3) ​ $ (45.1) ​ $ (29.1) ​ $ (26.0) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss, net of taxes ​ $ (64.2) ​ $ (56.2) ​ $ (4.4) ​ $ (2.8) ​ Prior service credit, net of taxes ​ 2.5 ​ 4.3 ​ 16.6 ​ 19.1 ​ Total ​ $ (61.7) ​ $ (51.9) ​ $ 12.2 ​ $ 16.3 ​
Schedule of information for qualified pension plans with an accumulated benefit obligation in excess of plan assets	The information for qualified defined benefit pension plans with an accumulated benefit obligation in excess of plan assets at December 31, 2020 and 2019 are shown below: ​ ​ ​ ​ ​ ​ ​ ​ ​ (In millions) 2020 2019 Projected benefit obligation ​ $ 261.4 ​ $ 238.3 ​ Accumulated benefit obligation ​ $ 260.9 ​ $ 237.9 ​ Fair value of plan assets ​ $ 210.0 ​ $ 192.2 ​
Schedule of components of the net periodic benefit cost and other changes in plan assets and benefit obligations recognized in other comprehensive income	Components of the net periodic benefit cost and other amounts recognized in other comprehensive income (loss) for the qualified pension plans and the post-retirement benefit plans during 2020, 2019 and 2018 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension Benefits ​ Post-retirement Benefits ​ ​ December 31, ​ December 31, ​ (In millions) 2020 2019 2018 2020 2019 2018 Components of Net Periodic Benefit Cost (Benefit): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Service cost ​ $ 5.1 ​ $ 4.7 ​ $ 4.4 ​ $ 0.5 ​ $ 0.4 ​ $ 0.6 ​ Interest cost ​ 7.9 ​ 9.3 ​ 8.6 ​ 0.8 ​ 0.9 ​ 1.0 ​ Expected return on plan assets ​ (14.0) ​ (11.9) ​ (13.5) ​ — ​ — ​ — ​ Amortization of net loss (gain) ​ 4.5 ​ 5.2 ​ 4.6 ​ 0.5 ​ (0.1) ​ 1.5 ​ Amortization of prior service credit ​ (2.3) ​ (2.3) ​ (2.3) ​ (3.7) ​ (3.8) ​ (3.8) ​ Net periodic benefit cost ​ ​ 1.2 ​ ​ 5.0 ​ ​ 1.8 ​ ​ (1.9) ​ ​ (2.6) ​ ​ (0.7) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income, net of tax: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss (gain) ​ ​ 11.4 ​ ​ (1.7) ​ ​ 7.8 ​ ​ 2.0 ​ ​ 2.5 ​ ​ (4.7) ​ Amortization of net (loss) gain ​ (3.4) ​ (3.9) ​ (3.5) ​ (0.3) ​ 0.2 ​ (1.1) ​ Amortization of prior service credit ​ 1.7 ​ 1.7 ​ 1.7 ​ 2.8 ​ 2.8 ​ 2.8 ​ Total recognized in other comprehensive loss (income) ​ ​ 9.7 ​ ​ (3.9) ​ ​ 6.0 ​ ​ 4.5 ​ ​ 5.5 ​ ​ (3.0) ​ Total recognized in net periodic benefit cost and other comprehensive loss (income) ​ $ 10.9 ​ $ 1.1 ​ $ 7.8 ​ $ 2.6 ​ $ 2.9 ​ $ (3.7) ​
Schedule of weighted average assumptions used to determine benefit information	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension Benefits ​ Post-retirement Benefits ​ ​ December 31, ​ December 31, ​ ​ 2020 2019 2018 2020 2019 2018 Discount rate (1) 2.50 % 3.40 % 4.40 % 2.70 % 3.50 % 4.50 % Expected return on plan assets 7.25 % 7.50 % 7.50 % ​ ​ ​ ​ ​ ​ Rate of compensation increase 3.00 % 3.00 % 3.00 % 3.00 % 3.00 % 3.00 % Cash balance interest credit rate ​ 0.75 - 3.25 % 1.75 - 3.75 % 3.01 % ​ ​ ​ ​ ​ ​ Initial health care cost trend rate: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pre-65 group ​ ​ ​ ​ ​ ​ ​ 5.30 % 5.70 % 6.00 % Post-65 group ​ ​ ​ ​ ​ ​ ​ 5.40 % 5.90 % 6.30 % Ultimate health care cost trend rate ​ ​ ​ ​ ​ ​ ​ 4.40 % 4.40 % 4.40 % Year ultimate health care cost trend rate is reached: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pre-65 group ​ ​ ​ ​ ​ ​ ​ 2037 ​ 2037 ​ 2037 ​ Post-65 group ​ ​ ​ ​ ​ ​ ​ 2036 ​ 2036 ​ 2036 ​ (1) The Company derives a single equivalent rate utilizing a yield curve constructed from a portfolio of high-quality corporate bonds with various maturities.
Schedule of amounts recognized on balance sheet and accumulated comprehensive income	​ ​ ​ ​ ​ ​ ​ ​ ​ Non-qualified ​ Pension Benefits ​ December 31, ​ (In millions) ​ 2020 2019 Current liabilities ​ $ (1.7) ​ $ (2.1) ​ Non-current liabilities, net ​ ​ (2.6) ​ ​ (2.3) ​ Total ​ $ (4.3) ​ $ (4.4) ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss, net of taxes ​ $ (0.8) ​ $ (0.6) ​ Prior service credit, net of taxes ​ ​ 0.1 ​ ​ 0.2 ​ Total ​ $ (0.7) ​ $ (0.4) ​
Schedule of estimated benefit payments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Non-qualified ​ ​ ​ ​ Pension ​ Pension ​ Post-retirement ​ Year (in millions) ​ Benefits ​ Benefits ​ Benefits (1) 2021 ​ $ 14.0 ​ $ 1.7 ​ $ 1.0 ​ 2022 ​ 14.4 ​ — ​ 1.0 ​ 2023 ​ 14.6 ​ 2.2 ​ 1.0 ​ 2024 ​ 14.7 ​ — ​ 1.1 ​ 2025 ​ 14.9 ​ — ​ 1.1 ​ 2026-2030 ​ ​ 76.2 ​ ​ 0.6 ​ ​ 5.5 ​ Total ​ $ 148.8 ​ $ 4.5 ​ $ 10.7 ​ (1) Net of plan participants’ contributions and Medicare Part D subsidies.
Schedule of information regarding the entity's participation in the multi-employer pension plans	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pension ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Protection Act ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Zone as of ​ FIP/RP Status ​ ​ ​ Contributions of Matson ​ ​ ​ ​ ​ ​ EIN/Pension ​ ​ ​ December 31, ​ Pending/ ​ 5% ​ (in millions) ​ Surcharge ​ Expiration Pension Funds Plan Number Notes 2020 2019 Implemented Contributor 2020 2019 2018 Imposed Date (2) American Radio Association Pension Fund 13-6161999-001 ​ ​ Green Green Implemented ​ Yes ​ $ 1.0 ​ $ 1.1 ​ $ 1.0 No 6/15/2028 ​ Hawaii Terminals Multiemployer Pension Plan 20-0389370-001 ​ (1) ​ Yellow Orange Implemented ​ Yes ​ ​ 5.8 ​ ​ 5.7 ​ ​ 5.7 No 6/30/2022 ​ Hawaii Stevedoring Multiemployer Retirement Plan 99-0314293-001 ​ (1) ​ Green Yellow Implemented ​ Yes ​ 4.6 ​ 4.4 ​ 4.3 No 6/30/2022 ​ Master, Mates and Pilots Pension Plan 13-6372630-001 ​ ​ ​ Green Green No ​ Yes ​ 3.2 ​ 3.4 ​ 3.0 No ​ 6/15/2027, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 6/15/2028 ​ Masters, Mates and Pilots Adjustable Pension Plan 37-1719247-001 ​ ​ ​ Green Green No ​ Yes ​ 1.8 ​ 1.9 ​ 1.7 No ​ 6/15/2027, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 6/15/2028 ​ MEBA Pension Trust - Defined Benefit Plan 51-6029896-001 ​ ​ ​ Green Green No ​ Yes ​ 4.1 ​ 4.3 ​ 4.0 No 6/15/2022, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 6/15/2028 ​ OCU Pension Trust Plan 26-1574440-001 ​ ​ ​ Green Green No ​ No ​ 0.2 ​ 0.2 ​ 0.2 No 6/30/2023 ​ MFOW Supplementary Pension Plan ​ 94-6201677-001 ​ ​ ​ Yellow ​ Green ​ No ​ Yes ​ ​ 0.1 ​ ​ 0.1 ​ ​ — ​ No ​ 6/30/2021 ​ SIU Pacific District Pension Plan ​ 94-6061923-001 ​ ​ ​ Green ​ Green ​ No ​ Yes ​ ​ 1.3 ​ ​ 1.5 ​ ​ 1.2 ​ No ​ 6/30/2021 ​ Alaska Teamster - Employer Pension Plan ​ 92-6003463-024 ​ ​ ​ Red ​ Red ​ Implemented ​ Yes ​ ​ 3.3 ​ ​ 1.9 ​ ​ 1.9 ​ Yes ​ 6/30/2021, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 6/30/2022, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 6/30/2023, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 6/30/2024 ​ All Alaska Longshore Pension Plan ​ 91-6085352-001 ​ ​ ​ Green ​ Green ​ No ​ Yes ​ ​ 1.3 ​ ​ 1.2 ​ ​ 1.0 ​ No ​ 6/30/2022 ​ Western Conference of Teamsters Pension Plan ​ 91-6145047-001 ​ ​ ​ Green ​ Green ​ No ​ No ​ ​ 1.6 ​ ​ 1.5 ​ ​ 1.4 ​ No ​ 3/31/2023 ​ Western Conference of Teamsters Supplemental Benefit Trust ​ 95-3746907-001 ​ ​ ​ Green ​ Green ​ No ​ No ​ ​ — ​ ​ — ​ ​ — ​ No ​ 3/31/2023 ​ OPEIU Local 153 Pension Plan ​ 13-2864289-001 ​ ​ ​ Red ​ Red ​ Implemented ​ No ​ ​ 0.1 ​ ​ 0.1 ​ ​ 0.1 ​ No ​ 11/9/2023 ​ Seafarers Pension Plan ​ 13-6100329-001 ​ (3) ​ Green ​ Green ​ No ​ No ​ ​ — ​ ​ — ​ ​ — ​ No ​ 6/30/2022 ​ Total ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 28.4 ​ $ 27.3 ​ $ 25.5 ​ ​ ​ ​ ​ (1) The Hawaii Terminals Multiemployer Pension Plan merged into the Hawaii Stevedoring Multiemployer Retirement Plan effective January 1, 2021 and formally known as the Hawaii Longshore Pension Plan. (2) Represents the expiration date of the collective bargaining agreement. (3) The Company does not make contributions directly to the Seafarers Pension Plan. Instead, contributions are made to the Seafarers Health and Benefits Plan, and are subsequently re-allocated to the Seafarers Pension Plan at the discretion of the plan Trustee. ​

MULTI-EMPLOYER WITHDRAWAL LIA_2

MULTI-EMPLOYER WITHDRAWAL LIABILITIES (Tables)	12 Months Ended
	Dec. 31, 2020
MULTI-EMPLOYER WITHDRAWAL LIABILITIES
Schedule of future estimated annual payments to the multi-employer pension plan	​ ​ ​ ​ ​ Year (in millions) ​ Total 2021 $ 4.1 2022 ​ ​ 4.1 2023 ​ ​ 4.1 2024 ​ ​ 4.1 2025 ​ ​ 4.1 Thereafter ​ ​ 59.7 Total remaining future undiscounted payments due to the ILA-PRSSA pension fund ​ ​ 80.2 Less: amount representing interest ​ ​ (23.3) Present value of multi-employer withdrawal liability ​ ​ 56.9 Current portion of multi-employer withdrawal liability (see Note 2) ​ ​ (4.1) Long-term portion of multi-employer withdrawal liability (see Note 2) $ 52.8

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)	12 Months Ended
	Dec. 31, 2020
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS).
Schedule of changes in accumulated other comprehensive income (loss) by component, net of tax	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Non- ​ ​ Accumulated ​ ​ ​ ​ ​ Post- ​ Qualified ​ ​ ​ ​ Other ​ ​ Pension ​ Retirement ​ Pension ​ ​ ​ ​ Comprehensive (In millions) ​ Benefits ​ Benefits ​ Benefits ​ Other ​ Income (Loss) Balance at December 31, 2018 ​ $ (55.8) ​ $ 21.7 ​ $ (0.1) ​ $ (0.3) ​ $ (34.5) ​ Amortization of prior service cost ​ (1.7) ​ ​ (2.6) ​ ​ (0.1) ​ ​ (0.1) ​ (4.5) ​ Amortization of net loss (gain) ​ ​ 5.6 ​ ​ (2.8) ​ ​ (0.2) ​ ​ 0.1 ​ 2.7 ​ Other adjustments ​ ​ — ​ — ​ — ​ (0.6) ​ (0.6) ​ Balance at December 31, 2019 ​ (51.9) ​ 16.3 ​ (0.4) ​ (0.9) ​ (36.9) ​ Amortization of prior service cost ​ (1.8) ​ ​ (2.8) ​ ​ (0.1) ​ ​ — ​ (4.7) ​ Amortization of net loss (gain) ​ (8.0) ​ ​ (1.3) ​ ​ (0.1) ​ ​ — ​ (9.4) ​ Foreign currency exchange ​ ​ — ​ ​ — ​ ​ — ​ ​ 0.5 ​ ​ 0.5 ​ Other adjustments ​ — ​ ​ — ​ ​ — ​ ​ (0.3) ​ (0.3) ​ Balance at December 31, 2020 ​ $ (61.7) ​ $ 12.2 ​ $ (0.6) ​ $ (0.7) ​ $ (50.8) ​ ​

EARNINGS PER-SHARE (Tables)

EARNINGS PER-SHARE (Tables)	12 Months Ended
	Dec. 31, 2020
EARNINGS PER-SHARE
Schedule of basic and diluted earnings per share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, 2020 ​ Year Ended December 31, 2019 ​ Year Ended December 31, 2018 ​ ​ ​ Weighted Per ​ ​ Weighted Per ​ ​ Weighted Per ​ ​ ​ ​ ​ Average ​ Common ​ ​ ​ ​ Average ​ Common ​ ​ ​ ​ Average ​ Common ​ ​ Net ​ Common ​ Share ​ Net ​ Common ​ Share ​ Net ​ Common ​ Share (In millions, except per share amounts) ​ Income ​ Shares ​ Amount ​ Income ​ Shares ​ Amount ​ Income ​ Shares ​ Amount Basic: ​ $ 193.1 43.1 ​ $ 4.48 ​ $ 82.7 42.8 ​ $ 1.93 ​ $ 109.0 42.7 ​ $ 2.55 ​ Effect of Dilutive Securities: ​ ​ ​ 0.4 ​ ​ (0.04) ​ ​ ​ 0.5 ​ ​ (0.02) ​ ​ ​ 0.3 ​ ​ (0.02) ​ Diluted: ​ $ 193.1 ​ 43.5 ​ $ 4.44 ​ $ 82.7 ​ 43.3 ​ $ 1.91 ​ $ 109.0 ​ 43.0 ​ $ 2.53 ​

SHARE-BASED AWARDS (Tables)

SHARE-BASED AWARDS (Tables)	12 Months Ended
	Dec. 31, 2020
SHARE-BASED AWARDS
Summary of Compensation expense and Other Measures Related to Share-Based awards	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, Share-based compensation expense, net of estimated forfeitures (in millions) 2020 2019 2018 Share-based compensation expense ​ $ 18.8 ​ $ 11.3 ​ $ 12.1 ​ Intrinsic value of options exercised ​ $ 5.8 ​ $ 0.5 ​ $ 0.5 ​ Tax benefit realized upon stock vesting ​ $ 3.3 ​ $ 2.0 ​ $ 2.7 ​ Fair value of stock vested ​ $ 13.1 ​ $ 8.2 ​ $ 10.8 ​
Stock Option Activity	Stock option activity for the year ended December 31, 2020 was as follows (in thousands, except weighted average exercise price and weighted average contractual life): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Weighted ​ ​ ​ ​ ​ Average ​ Average ​ Aggregate ​ ​ 2007 Plan ​ Exercise ​ Contractual ​ Intrinsic ​ ​ Shares ​ Price ​ Life ​ Value Outstanding at December 31, 2019 173 $ 22.30 ​ ​ ​ ​ ​ ​ Exercised (172) ​ $ 22.31 ​ ​ ​ ​ ​ ​ Outstanding at December 31, 2020 1 $ 20.84 0.1 ​ $ 35 ​ Exercisable at December 31, 2020 1 $ 20.84 0.1 ​ $ 35 ​
Non-Vested Restricted Stock Unit Activity	The following table summarizes non-vested restricted stock unit activity through December 31, 2020 (in thousands, except weighted average grant-date fair value amounts): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2007 Plan 2016 Plan Total Weighted ​ ​ Restricted ​ Restricted ​ Restricted ​ Average Grant- ​ ​ ​ Stock Units ​ Stock Units ​ Stock Units ​ Date Fair Value Outstanding at December 31, 2019 8 770 778 ​ $ 33.39 ​ Granted ​ — ​ 341 ​ 341 ​ ​ 38.68 ​ Settlement of Performance Shares (1) ​ — ​ 38 ​ 38 ​ ​ 36.55 ​ Vested ​ (5) ​ (339) ​ (344) ​ ​ 34.86 ​ Canceled ​ — ​ (21) ​ (21) ​ ​ 34.59 ​ Outstanding at December 31, 2020 3 789 792 ​ $ 35.14 ​ (1) Represents shares paid out above target.

FAIR VALUE OF FINANCIAL INSTR_2

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2020
FAIR VALUE OF FINANCIAL INSTRUMENTS
Schedule of fair value measurement	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quoted Prices in ​ Significant ​ Significant ​ ​ ​ Total ​ ​ ​ Active Markets ​ Observable ​ Unobservable ​ ​ Carrying Value Total (Level 1) Inputs (Level 2) Inputs (Level 3) ​ (In millions) ​ December 31, 2020 ​ Fair Value Measurements at December 31, 2020 ​ Cash and cash equivalents ​ $ 14.4 ​ $ 14.4 ​ $ 14.4 ​ $ — ​ $ — ​ Restricted cash ​ $ 5.3 ​ $ 5.3 ​ $ 5.3 ​ $ — ​ $ — ​ Variable rate debt ​ $ 71.8 ​ $ 71.8 ​ $ — ​ $ 71.8 ​ $ — ​ Fixed rate debt ​ $ 688.3 ​ $ 686.7 ​ $ — ​ $ 686.7 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (In millions) December 31, 2019 ​ Fair Value Measurements at December 31, 2019 ​ Cash and cash equivalents ​ $ 21.2 ​ $ 21.2 $ 21.2 ​ $ — ​ $ — ​ Restricted cash ​ $ 7.2 ​ $ 7.2 ​ $ 7.2 ​ $ — ​ $ — ​ Variable rate debt ​ $ 379.1 ​ $ 379.1 ​ $ — ​ $ 379.1 ​ $ — ​ Fixed rate debt ​ $ 579.3 ​ $ 585.9 ​ $ — ​ $ 585.9 ​ $ — ​

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2020
COMMITMENTS AND CONTINGENCIES
Schedule of Commitments and Contractual Obligations	Commitments and contractual obligations, excluding debt obligations (see Note 8), lease commitments (see Note 9), pension and post-retirement plan commitments, and multi-employer bargaining plan withdrawal obligations (see Note 11 and 12), are as follows as of December 31, 2020: ​ ​ ​ ​ ​ ​ Commitments and Contractual Obligations (in millions) Total Standby letters of credit (1) ​ $ 8.1 ​ Bonds (2) ​ $ 33.2 ​ Vendor and other obligations (3) ​ $ 69.1 ​ (1) Standby letters of credit are required for the Company’s uninsured workers’ compensation and other insurance programs, and other needs. (2) Bonds are required for U.S. Customs and other related matters. (3) Vendor and other obligations include: (i) non-cancellable contractual capital project obligations; (ii) dry-docking related obligations; and (iii) other contractual obligations. Amounts are considered obligations if a contract has been agreed to specifying significant terms of the contract, and the amounts are not reflected in the Consolidated Balance Sheets. ​

QUARTERLY INFORMATION (Unaudi_2

QUARTERLY INFORMATION (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2020
QUARTERLY INFORMATION (Unaudited)
Schedule of quarterly financial information	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quarters in the Year Ended December 31, 2020 (In millions, except per share amounts) Q1 Q2 Q3 Q4 Operating Revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ocean Transportation ​ $ 400.9 ​ $ 410.8 ​ $ 498.3 ​ $ 543.9 ​ Logistics ​ 113.0 ​ 113.3 ​ 146.9 ​ 156.2 ​ Total Operating Revenue ​ $ 513.9 ​ $ 524.1 ​ $ 645.2 ​ $ 700.1 ​ Operating Income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ocean Transportation ​ $ 7.9 ​ $ 42.3 ​ $ 86.5 ​ $ 108.1 ​ Logistics ​ 5.1 ​ 8.9 ​ 11.9 ​ 9.6 ​ Total Operating Income ​ 13.0 ​ 51.2 ​ 98.4 ​ 117.7 ​ Interest expense, net ​ (8.6) ​ (8.2) ​ (5.7) ​ (4.9) ​ Other income (expense), net ​ ​ 0.6 ​ ​ 1.5 ​ ​ 2.4 ​ ​ 1.6 ​ Income before Income Taxes ​ 5.0 ​ 44.5 ​ 95.1 ​ 114.4 ​ Income Taxes ​ (1.2) ​ (11.7) ​ (24.2) ​ (28.8) ​ Net Income ​ $ 3.8 ​ $ 32.8 ​ $ 70.9 ​ $ 85.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic Earnings Per Share: ​ $ 0.09 ​ $ 0.76 ​ $ 1.65 ​ $ 1.99 ​ Diluted Earnings Per Share: ​ $ 0.09 ​ $ 0.76 ​ $ 1.63 ​ $ 1.96 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quarters in the Year Ended December 31, 2019 (In millions, except per share amounts) Q1 Q2 Q3 Q4 Operating Revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ocean Transportation ​ $ 397.9 ​ $ 415.4 ​ $ 437.2 ​ $ 416.1 ​ Logistics ​ 134.5 ​ 142.5 ​ 134.9 ​ 124.6 ​ Total Operating Revenue ​ $ 532.4 ​ $ 557.9 ​ $ 572.1 ​ $ 540.7 ​ Operating Income: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ocean Transportation ​ $ 9.4 ​ $ 19.7 ​ $ 43.9 ​ $ 17.8 ​ Logistics ​ 8.1 ​ 11.3 ​ 11.3 ​ 7.6 ​ Total Operating Income ​ 17.5 ​ 31.0 ​ 55.2 ​ 25.4 ​ Interest expense, net ​ (4.6) ​ (6.1) ​ (6.2) ​ (5.6) ​ Other income (expense), net ​ ​ 0.6 ​ ​ 0.8 ​ ​ (0.5) ​ ​ 0.3 ​ Income before Income Taxes ​ 13.5 ​ 25.7 ​ 48.5 ​ 20.1 ​ Income Taxes ​ (1.0) ​ (7.3) ​ (12.3) ​ (4.5) ​ Net Income ​ $ 12.5 ​ $ 18.4 ​ $ 36.2 ​ $ 15.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic Earnings Per Share: ​ $ 0.29 ​ $ 0.43 ​ $ 0.84 ​ $ 0.36 ​ Diluted Earnings Per Share: ​ $ 0.29 ​ $ 0.43 ​ $ 0.84 ​ $ 0.36 ​ ​
Schedule of infrequent transactions impacting the segment results	The following infrequent transactions impacted the Company’s quarterly segment results during the year ended December 31, 2019. There were no infrequent transactions recorded during the year ended December 31, 2020. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quarters in the Year Ended December 31, 2019 (In millions) Q1 Q2 Q3 Q4 Income taxes - Discrete adjustments related to the Tax Act (1) ​ $ 2.9 ​ $ — ​ $ — ​ $ — ​ (1) Amounts relate to discrete adjustments as a result of applying the Tax Act during the year ended December 31, 2019.

DESCRIPTION OF THE BUSINESS (De

DESCRIPTION OF THE BUSINESS (Details)	12 Months Ended
	Dec. 31, 2020facilitysegment
DESCRIPTION OF THE BUSINESS
Number of reportable segments | segment	2
SSAT
DESCRIPTION OF THE BUSINESS
Number of terminal facilities on which SSAT provided terminal and stevedoring services on the U.S. West Coast	7
Ocean Transportation | SSAT
DESCRIPTION OF THE BUSINESS
Ownership interest in SSAT (as a percent)	35.00%
MatNav | SSAT
DESCRIPTION OF THE BUSINESS
Number of terminal facilities on which SSAT provided terminal and stevedoring services on the U.S. West Coast	3

SIGNIFICANT ACCOUNTING POLICI_4

SIGNIFICANT ACCOUNTING POLICIES - FISCAL YEAR (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
SIGNIFICANT ACCOUNTING POLICIES
Fiscal Period Duration	364 days	364 days

SIGNIFICANT ACCOUNTING POLICI_5

SIGNIFICANT ACCOUNTING POLICIES - CASH AND ACCOUNTS RECEIVABLE (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash and Cash Equivalents
Outstanding checks in excess of funds on deposits	$ 19.9	$ 13.8
Restricted cash	5.3	7.2
Allowance for doubtful accounts
Balance at Beginning of year	4.3	4.8	$ 4.6
Expense	2.9	0.6	0.8
Write-offs and Other	(0.9)	(1.1)	(0.6)
Balance at End of Year	6.3	4.3	$ 4.8
Prepaid and Other Assets:
Prepaid fuel	10.8	13.7
Prepaid insurance and insurance related receivables	7.5	13.4
Prepaid operating expenses	5.4	5.7
Restricted cash - vessel construction obligations	5.3	7.2
Income tax receivables	0.3	12.8
Other	8.8	9.7
Total	38.1	62.5
Other Long-term Assets
Vessel and equipment spare parts	11.5	12.4
Insurance related receivables	10.5	10.6
Deferred loan fees	2.7	2.1
Cloud computing software costs	2.4
Income tax receivables	2.1	11.5
Other	3.8	1.2
Total	$ 33	$ 37.8

SIGNIFICANT ACCOUNTING POLICI_6

SIGNIFICANT ACCOUNTING POLICIES - PROPERTY AND EQUIPMENT AND OTHER (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)item	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Impairment of Investment
Impairment charges related to investment in SSAT	$ 0	$ 0	$ 0
Capitalized Interest
Interest Costs Capitalized	$ 7.4	$ 15.6	$ 18.7
Dry-docking
Number of dry-docking inspections to be made within a specified period | item	2
Dry-dock inspections interval, minimum	36 months
Minimum
Dry-docking
Period within which number of specified dry-docking inspections to be made	2 years
Maximum
Dry-docking
Period within which number of specified dry-docking inspections to be made	5 years
Vessels
Depreciation
Useful life	40 years
Machinery And Equipment
Depreciation
Useful life	30 years
Terminal Facilities
Depreciation
Useful life	35 years

SIGNIFICANT ACCOUNTING POLICI_7

SIGNIFICANT ACCOUNTING POLICIES - DEFERRED LOAN, DIVIDENDS AND OTHER (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Dividends
Dividends (per share)	$ 0.90	$ 0.86	$ 0.82
Capitalized Computer Software Costs
Cloud computing software costs	$ 2.4

SIGNIFICANT ACCOUNTING POLICI_8

SIGNIFICANT ACCOUNTING POLICIES - ACCRUED AND OTHER LIABILITIES (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Intangible assets
Impairment charges related to finite-lived intangible assets	$ 0	$ 0	$ 0
Impairment charges related to indefinite-lived intangible assets and goodwill for impairment	0	0	$ 0
Accrued and other liabilities
Payroll and vacation	29.2	28.5
Employee incentives and other	25.9	14.7
Uninsured risks and related liabilities - short term	7	12.6
Multi-employer withdrawal liability - short-term (see Note 12)	10.6	10.8
Income tax liabilities	11.7	2.3
Deferred revenues	4.2	6.9
Interest on debt	3.4	4.9
Pension and post-retirement liabilities - short term (see Note 11)	2.7	3.1
Other short-term liabilities	2.1	2.2
Total	96.8	86
Other long-term liabilities
Pension and post-retirement liabilities (see Note 11)	82	73.4
Multi-employer withdrawal liability (see Note 12)	52.8	54.8
Uninsured risks and related liabilities	25.4	26.6
Other long-term liabilities	5.6	2.6
Total	$ 165.8	$ 157.4
Customer Relationships. | Maximum
Intangible assets
Expected useful lives	21 years

SIGNIFICANT ACCOUNTING POLICI_9

SIGNIFICANT ACCOUNTING POLICIES - CUSTOMER CONCENTRATION (Details) - Serves customers - customer	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Ocean Transportation
Number of largest customers	10	10	10
Number of customers	0
Ocean Transportation | Revenue
Concentration percentage	22.00%	23.00%	24.00%
Logistics
Number of largest customers	10	10	10
Number of customers	0
Logistics | Revenue
Concentration percentage	19.00%	21.00%	23.00%

SIGNIFICANT ACCOUNTING POLIC_10

SIGNIFICANT ACCOUNTING POLICIES - RECOGNITION OF REVENUES AND EXPENSES (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Total	$ 700.1	$ 645.2	$ 524.1	$ 513.9	$ 540.7	$ 572.1	$ 557.9	$ 532.4	$ 2,383.3	$ 2,203.1	$ 2,222.8
Ocean Transportation
Total	543.9	498.3	410.8	400.9	416.1	437.2	415.4	397.9
Logistics
Total	$ 156.2	$ 146.9	$ 113.3	$ 113	$ 124.6	$ 134.9	$ 142.5	$ 134.5
Ocean Transportation
Ocean Transportation services									1,821.7	1,625.8	1,599.3
Terminal and other related services									19.1	24.8	23
Fuel sales									7.3	10.1	12.2
Vessel management and related services									$ 5.8	$ 5.9	$ 6.8
Percentage of ocean transportation revenues and fuel sales denominated in foreign currency									3.00%	3.00%	3.00%
Total									$ 1,853.9	$ 1,666.6	$ 1,641.3
Logistics
Transportation Brokerage and Freight Forwarding Services									477	489	532.5
Warehouse and distribution services									36.2	34.1	33.8
Supply chain management and other services									16.2	13.4	15.2
Total									$ 529.4	$ 536.5	$ 581.5
Percentage of transportation brokerage and freight forwarding services revenue denominated in foreign currency									3.00%	3.00%	3.00%
Reclassify Transportation Brokerage and Freight Forwarding Services | Logistics
Transportation Brokerage and Freight Forwarding Services										$ (15.8)	$ (16.6)
Warehouse and distribution services										$ 15.8	$ 16.6

REPORTABLE SEGMENTS (Details)

REPORTABLE SEGMENTS (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020USD ($)	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2020USD ($)segment	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Segment results
Number of segments | segment									2
Fiscal Period Duration									364 days	364 days
Total Operating Revenue	$ 700.1	$ 645.2	$ 524.1	$ 513.9	$ 540.7	$ 572.1	$ 557.9	$ 532.4	$ 2,383.3	$ 2,203.1	$ 2,222.8
Operating Income	117.7	98.4	51.2	13	25.4	55.2	31	17.5	280.3	129.1	163.8
Interest expense, net	(4.9)	(5.7)	(8.2)	(8.6)	(5.6)	(6.2)	(6.1)	(4.6)	(27.4)	(22.5)	(18.7)
Other income (expense), net	1.6	2.4	1.5	0.6	0.3	(0.5)	0.8	0.6	6.1	1.2	2.6
Income before Income Taxes	114.4	95.1	44.5	5	20.1	48.5	25.7	13.5	259	107.8	147.7
Income taxes	(28.8)	(24.2)	(11.7)	(1.2)	(4.5)	(12.3)	(7.3)	(1)	(65.9)	(25.1)	(38.7)
Net Income	85.6	70.9	32.8	3.8	15.6	36.2	18.4	12.5	193.1	82.7	109
Depreciation and Amortization									114.9	100.4	94.4
Deferred dry-docking amortization									25.1	34.3	37.4
Total Depreciation and Amortization									140	134.7	131.8
Assets	2,900.6				2,845.4				2,900.6	2,845.4
Income from SSAT									26.3	20.8	36.8
Ocean Transportation
Segment results
Total Operating Revenue	543.9	498.3	410.8	400.9	416.1	437.2	415.4	397.9
Operating Income	108.1	86.5	42.3	7.9	17.8	43.9	19.7	9.4
Ocean Transportation | SSAT
Segment results
Assets	1,543.8				1,583.8				1,543.8	1,583.8
Income from SSAT									26.3	20.8	36.8
Equity method investments	48.7				76.2				48.7	76.2
Logistics
Segment results
Total Operating Revenue	156.2	146.9	113.3	113	124.6	134.9	142.5	134.5
Operating Income	9.6	$ 11.9	$ 8.9	$ 5.1	7.6	$ 11.3	$ 11.3	$ 8.1
Operating segments
Segment results
Total Operating Revenue									2,383.3	2,203.1	2,222.8
Operating Income									280.3	129.1	163.8
Capital Expenditures									192.3	310.3	401.2
Depreciation and Amortization									114.9	100.4	94.4
Assets	2,900.6				2,845.4				2,900.6	2,845.4
Operating segments | Ocean Transportation
Segment results
Total Operating Revenue									1,853.9	1,666.6	1,641.3
Operating Income									244.8	90.8	131.1
Capital Expenditures									190	294.5	385.4
Depreciation and Amortization									107.4	93.6	87
Deferred dry-docking amortization									25.1	34.3	37.4
Assets	2,431.1				2,424.5				2,431.1	2,424.5
Operating segments | Logistics
Segment results
Total Operating Revenue									529.4	536.5	581.5
Operating Income									35.5	38.3	32.7
Capital Expenditures									2.3	15.8	15.8
Depreciation and Amortization									7.5	6.8	7.4
Assets	$ 469.5				$ 420.9				469.5	420.9
Intersegment Eliminations
Segment results
Total Operating Revenue									115.5	102.3	95.4
Intersegment Eliminations | Ocean Transportation
Segment results
Total Operating Revenue									59.1	52.8	51.7
Intersegment Eliminations | Logistics
Segment results
Total Operating Revenue									$ 56.4	$ 49.5	$ 43.7

INVESTMENT IN SSAT (Details)

INVESTMENT IN SSAT (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Investments in affiliates
Investment in Terminal Joint Venture	$ 48.7	$ 76.2
Financial information for equity method investment
Company's share of net income	26.3	20.8	$ 36.8
Distributions Received	55.4	25.2	42
Current assets	305.9	289.6
Non-current assets	2,594.7	2,555.8
Total Assets	2,900.6	2,845.4
Current liabilities	511.5	436.7
Non-current liabilities	1,427.9	1,603
Total Liabilities and Equity	2,900.6	2,845.4
SSAT
Investments in affiliates
Increase in investment in SSAT	$ 2.2
Ocean Transportation | SSAT
Investments in affiliates
Ownership interest accounted in the related party terminal joint venture (as a percent)	35.00%
Cost of services from transactions with unconsolidated affiliate	$ 251.6	218.7	213.4
Accounts payable and accrued liabilities	29.8	63.6
Financial information for equity method investment
Company's share of net income	26.3	20.8	36.8
Current assets	294.3	300.8
Non-current assets	1,249.5	1,283
Total Assets	1,543.8	1,583.8
Current liabilities	238.2	201.9
Non-current liabilities	1,179.9	1,179.2
Equity	125.7	202.7
Total Liabilities and Equity	1,543.8	1,583.8
Operating revenue	1,091.6	1,098.3	1,074.2
Operating costs and expenses	1,003.2	1,035.3	963.7
Operating Income	88.4	63	110.5
Net Income	$ 76.6	$ 57.2	$ 104.9

PROPERTY AND EQUIPMENT - SUMMAR

PROPERTY AND EQUIPMENT - SUMMARY (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property and equipment
Cost	$ 2,912.3	$ 2,836.7
Accumulated depreciation	1,222.4	1,238.6
Property and equipment, net	1,689.9	1,598.1
Depreciation Expense	97.1	86.3	$ 80.5
Vessels
Property and equipment
Cost	2,191.6	1,653.5
Accumulated depreciation	785.5	818.5
Property and equipment, net	1,406.1	835
Containers and equipment
Property and equipment
Cost	572.3	544.5
Accumulated depreciation	391.8	378.8
Property and equipment, net	180.5	165.7
Terminal facilities and other property
Property and equipment
Cost	119.8	114.4
Accumulated depreciation	45.1	41.3
Property and equipment, net	74.7	73.1
Vessel construction in progress
Property and equipment
Cost		488.9
Property and equipment, net		488.9
Other construction in progress
Property and equipment
Cost	28.6	35.4
Property and equipment, net	$ 28.6	$ 35.4

GOODWILL AND INTANGIBLES ASSE_3

GOODWILL AND INTANGIBLES ASSETS - CHANGES IN GOODWILL (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Goodwill [Line Items]
Goodwill	$ 327.8	$ 327.8
Ocean Transportation
Goodwill [Line Items]
Goodwill	222.6
Logistics
Goodwill [Line Items]
Goodwill	105.2
Logistics | Span Alaska
Goodwill [Line Items]
Goodwill	78.6
Logistics | Other Acquisitions
Goodwill [Line Items]
Goodwill	$ 26.6

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS - INTANGIBLE ASSETS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Intangible assets
Gross Amount	$ 258	$ 258
Accumulated Amortization	(66)	(55.1)
Net Amount	192	202.9
Aggregate intangible asset amortization	10.9	11.1	$ 11.2
Estimated amortization expenses related to intangibles
2021	10.9
2022	10.7
2023	10.7
2024	10.7
2025	10.7
Thereafter	111
Total	164.7
Ocean Transportation | Customer Relationships.
Intangible assets
Gross Amount	140.6	140.6
Accumulated Amortization	(37.9)	(31.2)
Net Amount	$ 102.7	109.4
Ocean Transportation | Customer Relationships. | Horizon
Intangible assets
Expected useful life	21 years
Finite-Lived intangible assets acquired	$ 140.6
Logistics
Intangible assets
Gross Amount	117.4	117.4
Accumulated Amortization	(28.1)	(23.9)
Net Amount	89.3	93.5
Logistics | Trade Names
Intangible assets
Indefinite-Lived intangible asset	27.3	27.3
Logistics | Span Alaska | Trade Names
Intangible assets
Indefinite-Lived intangible asset acquired	27.3
Logistics | Customer Relationships.
Intangible assets
Gross Amount	90.1	90.1
Accumulated Amortization	(28.1)	(23.9)
Net Amount	62	$ 66.2
Net Remaining Amount	$ 10.8
Expected useful life	13 years
Logistics | Customer Relationships. | Span Alaska
Intangible assets
Net Amount	$ 79.3
Expected useful life	20 years

CAPITAL CONSTRUCTION FUND (Deta

CAPITAL CONSTRUCTION FUND (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Maximum period to commit fund deposits for qualified purposes	25 years
Period over which deposits will be treated as non-qualified withdrawals	5 years
Accounts receivable, net	$ 253.4	$ 205.9
Eligible Accounts Receivable Assigned to CCF
Accounts receivable, net	$ 1.7

DEBT - SUMMARY (Details)

DEBT - SUMMARY (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Debt
Total Debt	$ 760.1	$ 958.4
Less current portion	(59.2)	(48.4)
Total Long-term Debt	700.9	910
Less: Deferred loan fees	(15.3)
Total Long-term Debt, net of deferred loan fees	$ 685.6	910
5.79%, payable through 2020
Debt
Total Debt		3.5
Interest rate (as a percent)	5.79%
3.66%, payable through 2023
Debt
Total Debt	$ 22.8	31.9
Interest rate (as a percent)	3.66%
4.16%, payable through 2027
Debt
Total Debt	$ 34	39.3
Interest rate (as a percent)	4.16%
3.37 %, payable through 2027
Debt
Total Debt	$ 75	75
Interest rate (as a percent)	3.37%
3.14%, payable through 2031
Debt
Total Debt	$ 169.6	188
Interest rate (as a percent)	3.14%
4.31%, payable through 2032
Debt
Total Debt	$ 27.9	30.3
Interest rate (as a percent)	4.31%
4.35%, payable through 2044
Debt
Total Debt		100
Interest rate (as a percent)	4.35%
3.92%, payable through 2045
Debt
Total Debt		69.5
Interest rate (as a percent)	3.92%
5.34%, payable through 2028
Debt
Total Debt	$ 17.6	19.8
Interest rate (as a percent)	5.34%
5.27%, payable through 2029
Debt
Total Debt	$ 19.8	22
Interest rate (as a percent)	5.27%
1.22 %, payable through 2043
Debt
Total Debt	$ 182
Interest rate (as a percent)	1.22%
1.35 %, payable through 2044
Debt
Total Debt	$ 139.6
Interest rate (as a percent)	1.35%
Revolving Credit Facility
Debt
Total Debt	$ 71.8	$ 379.1
Funds available under the revolving credit facility	$ 570.1
Interest rate during period (as a percent)	2.50%

DEBT - DESCRIPTION (Details)

DEBT - DESCRIPTION (Details)

Jun. 22, 2020USD ($)

Apr. 27, 2020USD ($)

Mar. 31, 2020

Dec. 21, 2016USD ($)

Sep. 14, 2016USD ($)

Jul. 31, 2015USD ($)

Jan. 31, 2014USD ($)

Aug. 31, 2004USD ($)

Sep. 30, 2003USD ($)

Jun. 30, 2012USD ($)item

Dec. 31, 2020USD ($)

Jul. 15, 2015

Debt

Payment of debt financing costs

$ 18,500,000

Proceeds from issuance of debt

325,500,000

Letters of credit

$ 8,100,000

Revolving Credit Facility

Debt

Interest rate during period (as a percent)

2.50%

Maximum borrowing capacity under revolving credit facility

$ 650,000,000

Uncommitted option to increase credit facility

250,000,000

Unused portion of credit facility

570,100,000

Debt covenant, maximum priority debt to be incurred by Foreign Subsidiaries

$ 20,000,000

Revolving Credit Facility | Minimum

Debt

Ratio of consolidated EBITDA to interest expense

3.50

Credit facility commitment fee percentage

0.25%

Revolving Credit Facility | Minimum | London Interbank Offered Rate (LIBOR)

Debt

Variable rate margin

1.75%

Revolving Credit Facility | Minimum | Base rate

Debt

Variable rate margin

0.75%

Revolving Credit Facility | Maximum

Debt

Credit facility commitment fee percentage

0.55%

Revolving Credit Facility | Maximum | London Interbank Offered Rate (LIBOR)

Debt

Variable rate margin

3.50%

Revolving Credit Facility | Maximum | Base rate

Debt

Variable rate margin

2.50%

Standby and commercial letters of credit

Debt

Standby letters of credit

$ 8,100,000

Maximum borrowing capacity under revolving credit facility

100,000,000

Standby and commercial letters of credit | Minimum

Debt

Line of credit fees percentage

1.75%

Standby and commercial letters of credit | Maximum

Debt

Line of credit fees percentage

3.50%

Swing Line Loans

Debt

Maximum borrowing capacity under revolving credit facility

$ 50,000,000

5.34%, payable through 2028

Debt

Interest rate (as a percent)

5.34%

5.34%, payable through 2028 | MatNav

Debt

Debt issued

$ 55,000,000

Interest rate (as a percent)

5.34%

Semi-annual payments

$ 1,100,000

5.79%, payable through 2020

Debt

Interest rate (as a percent)

5.79%

Annual principal payments

$ 3,500,000

5.27%, payable through 2029

Debt

Interest rate (as a percent)

5.27%

5.27%, payable through 2029 | MatNav

Debt

Debt issued

$ 55,000,000

Interest rate (as a percent)

5.27%

Semi-annual payments

$ 1,100,000

Senior Unsecured Long Term Debt

Debt

Debt issued

$ 100,000,000

Debt instrument term

30 years

Interest rate (as a percent)

4.35%

4.35%, payable through 2044

Debt

Interest rate (as a percent)

4.35%

Unsecured debt

Debt

Debt issued

$ 170,000,000

Number of tranches | item

3

Unsecured debt | Debt Instrument Redemption 2015 through 2016

Debt

Semi-annual payments

$ 4,600,000

Unsecured debt | Debt Instrument Redemption 2017 through mid-year 2023

Debt

Semi-annual payments

8,400,000

Unsecured debt | Debt Instrument Redemption Mid-year 2023 through mid-year 2027

Debt

Semi-annual payments

3,800,000

Unsecured debt | Debt Instrument Redemption After mid-year 2027

Debt

Semi-annual payments

1,200,000

Unsecured debt, tranche maturing in 2023

Debt

Debt issued

$ 77,500,000

Interest rate (as a percent)

3.66%

Unsecured debt, tranche maturing in 2027

Debt

Debt issued

$ 55,000,000

Interest rate (as a percent)

4.16%

Unsecured debt, tranche maturing in 2032

Debt

Debt issued

$ 37,500,000

Interest rate (as a percent)

4.31%

Notes 30 years

Debt

Debt issued

$ 75,000,000

Debt instrument term

30 years

Interest rate (as a percent)

3.92%

Senior Unsecured Series A Notes

Debt

Debt issued

$ 75,000,000

Debt instrument term

11 years

Interest rate (as a percent)

3.37%

Senior Unsecured Series A Notes | Debt Instrument Redemption 2021

Debt

Semi-annual payments

$ 5,800,000

Senior Unsecured Series A Notes | Debt Instrument Redemption 2022 through 2027

Debt

Semi-annual payments

$ 11,500,000

Title XI Notes | MatNav

Debt

Debt issued

$ 139,600,000

$ 185,900,000

Interest rate (as a percent)

1.35%

1.22%

Annual principal payments

$ 3,000,000

$ 4,000,000

Payment of debt financing costs

$ 6,700,000

$ 8,700,000

The Senior Unsecured Notes (The "Series D Notes")

Debt

Debt issued

$ 200,000,000

Debt instrument term

15 years

Interest rate (as a percent)

3.14%

Maturities of Long-term Debt

Semi-annual principal payments in year 2019

$ 6,000,000

Semi-annual principal payments in 2020 to 2023

9,200,000

Semi-annual principal payments in 2024 to 2031

$ 7,150,000

DEBT - REVOLVING CREDIT FACILIT

DEBT - REVOLVING CREDIT FACILITY (Details)	Jun. 22, 2020USD ($)	Apr. 27, 2020USD ($)	Mar. 31, 2020item	Sep. 14, 2016USD ($)	Dec. 31, 2020USD ($)item
Debt
Payment of debt financing costs					$ 18,500,000
Title XI Notes
Debt
The number of vessels committed to securing debt | item					2
Revolving Credit Facility
Debt
Maximum borrowing capacity under revolving credit facility					$ 650,000,000
Uncommitted option to increase credit facility					250,000,000
Funds available under the revolving credit facility					$ 570,100,000
Interest rate during period (as a percent)					2.50%
Covenant threshold for debt incurred					$ 331,000,000
Revolving Credit Facility | Minimum
Debt
Credit facility commitment fee percentage			0.25%
Ratio of consolidated EBITDA to interest expense					3.50
Revolving Credit Facility | Maximum
Debt
Credit facility commitment fee percentage			0.55%
Standby and commercial letters of credit
Debt
Maximum borrowing capacity under revolving credit facility					$ 100,000,000
Standby letters of credit					8,100,000
Standby and commercial letters of credit | Minimum
Debt
Line of credit fees percentage			1.75%
Standby and commercial letters of credit | Maximum
Debt
Line of credit fees percentage			3.50%
Swing Line Loans
Debt
Maximum borrowing capacity under revolving credit facility					50,000,000
The Senior Unsecured Notes (The "Series D Notes")
Debt
Debt issued				$ 200,000,000
Interest rate (as a percent)				3.14%
Debt instrument term				15 years
Maturities of Long-term Debt
Semi-annual principal payments in year 2019				$ 6,000,000
Semi-annual principal payments in 2020 to 2023				9,200,000
Semi-annual principal payments in 2024 to 2031				$ 7,150,000
Private Loan Facilities
Debt
Number of consecutive quarters | item			2
Additional interest rate based on the entity's consolidated leverage ratio			25.00%
London Interbank Offered Rate (LIBOR) | Revolving Credit Facility | Minimum
Debt
Variable rate margin			1.75%
London Interbank Offered Rate (LIBOR) | Revolving Credit Facility | Maximum
Debt
Variable rate margin			3.50%
Base rate | Revolving Credit Facility | Minimum
Debt
Variable rate margin			0.75%
Base rate | Revolving Credit Facility | Maximum
Debt
Variable rate margin			2.50%
MatNav | Title XI Notes
Debt
Minimum working capital covenant					$ 1
Debt instrument covenant ratio, maintenance of net worth					90.00%
Payment of debt financing costs	$ 6,700,000	$ 8,700,000
Debt issued	$ 139,600,000	$ 185,900,000
Interest rate (as a percent)	1.35%	1.22%
Annual principal payments	$ 3,000,000	$ 4,000,000
MatNav | Minimum | Title XI Notes
Debt
Debt instrument covenant, long-term debt to net worth					2.00%

DEBT - MATURITIES (Details)

DEBT - MATURITIES (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Debt maturities
2021	$ 59.2
2022	136.8
2023	60.4
2024	51.7
2025	51.7
Thereafter	400.3
Total Debt	$ 760.1	$ 958.4

DEBT - DEFERRED LOAN FEES (Deta

DEBT - DEFERRED LOAN FEES (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
DEBT
Deferred financing costs related to Title XI bonds and private placement debt amendments	$ 16.5
Deferred fees expensed related to the redemption of private placement debt	(0.3)
Amortization expense	(0.9)
Ending Balance	$ 15.3

DEBT - AMORTIZATION EXPENSE (De

DEBT - AMORTIZATION EXPENSE (Details) $ in Millions	Dec. 31, 2020USD ($)
DEBT
2021	$ 1.5
2022	1.2
2023	1.1
2024	1.1
2025	1
Thereafter	9.4
Total amortization expense of deferred loan fees	$ 15.3

LEASES - LEASE TERM (Details)

LEASES - LEASE TERM (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
Retained earnings	$ 658.1	$ 504.2
Adjustment | ASC 842
Lessee, Lease, Description [Line Items]
Retained earnings			$ 4.4
Real estate and terminal leases
Lessee, Lease, Description [Line Items]
Base term	65 years
Vessel charter leases
Lessee, Lease, Description [Line Items]
Base term	10 years
Operations equipment and other leases
Lessee, Lease, Description [Line Items]
Base term	8 years

LEASE - COMPONENTS OF LEASE COS

LEASE - COMPONENTS OF LEASE COST (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lease Cost
Operating lease cost	$ 83.1	$ 71.4
Short-term lease cost	10.6	5.9
Variable lease cost	0.8	0.4
Total lease cost	$ 94.5	$ 77.7

LEASE - OTHER INFORMATION (Deta

LEASE - OTHER INFORMATION (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lease Cost
Cash paid for amounts included in operating lease liabilities	$ 83.6	$ 71.3
Right of use assets obtained in the exchange for new operating lease liabilities	$ 70.1	$ 65.3
Weighted-average remaining operating lease term	7 years	7 years 6 months
Weighted-average incremental borrowing rate	3.70%	4.20%

LEASE - MATURITIES OF OPERATING

LEASE - MATURITIES OF OPERATING LEASE LIABILITIES (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Maturities of operating lease liabilities
2021	$ 80.5
2022	53.2
2023	47.3
2024	31.8
2024	23.9
Thereafter	65.6
Total lease payments	302.3
Less: Interest	(43)
Present value of operating lease liabilities	259.3
Less: Short-term portion	(72.4)	$ (66.6)
Long-term operating lease liabilities	$ 186.9	$ 198
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Liabilities, Current

LEASE - SALE AND LEASEBACK OF E

LEASE - SALE AND LEASEBACK OF EQUIPMENT (Details) - Multiple Tranches of Chassis and Container Equipment $ in Millions	Mar. 25, 2020USD ($)
Sale Leaseback Transaction [Line Items]
Net proceeds	$ 14.3
Base term	5 years

LEASES - Vessel Charter and Buy

LEASES - Vessel Charter and Buyer Lessor Guaranty (Details) - USD ($) $ in Millions	Nov. 26, 2018	Dec. 31, 2020
Sale Leaseback Transaction [Line Items]
Operating lease liability		$ 259.3
Vessel Charter, Sale and Leaseback Transaction
Sale Leaseback Transaction [Line Items]
Renewal option	true
Vessel Charter, Sale and Leaseback Transaction | Bareboat Charter Agreement
Sale Leaseback Transaction [Line Items]
Sale of subsequently leased back	$ 106
Rent payments per quarter	$ 3
Base term	5 years
Renewal term	2 years
Residual value guarantee option	true
Operating lease liability		$ 36
Purchase option price	$ 68.9
Purchase option price extended term	58.3
Maximum residual value guarantee amount	50.9
Maximum residual value guarantee amount extended term	$ 47.7

INCOME TAXES - SUMMARY (Details

INCOME TAXES - SUMMARY (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
INCOME TAXES
Income taxes - Discrete adjustments related to the Tax Act (1)								$ 2.9		$ (2.9)	$ 2.9
Current:
Federal										0.2	1.5
State									$ 8.7	3.2	2.1
Foreign									1.4	1.3	0.9
Discrete adjustments related to the Tax Act								2.9		(2.9)	2.9
Total									10.1	1.8	7.4
Deferred:
Deferred tax expense									55.8	23.3	31.3
Total income taxes	$ 28.8	$ 24.2	$ 11.7	$ 1.2	$ 4.5	$ 12.3	$ 7.3	$ 1	$ 65.9	$ 25.1	$ 38.7
Difference of Income tax expense from amounts computed by applying the statutory federal rate to income from continuing operations before income taxes
Computed federal income tax expense (as a percent)									21.00%	21.00%	21.00%	35.00%
State income tax (as a percent)									3.50%	4.10%	3.40%
Valuation allowance (as a percent)									(0.20%)	(0.30%)	(0.70%)
Foreign taxes (as a percent)									0.60%	1.20%	0.60%
Remeasurement and discrete adjustments related to Tax Act (as a percent)										(2.70%)	2.00%
Share-based payments (as a percent)									(0.50%)	(0.10%)	0.10%
Other-net (as a percent)									1.00%	0.10%	(0.20%)
Effective income tax rate , Percent, Total									25.40%	23.30%	26.20%
Valuation allowance related to foreign subsidiary losses									$ 0.6	$ 0.9	$ (1.1)
Valuation allowances	10				10.6				10	10.6
Deferred tax assets:
Operating lease liabilities	63.5				63.1				63.5	63.1
Pension and post-retirement plans	21.7				19.2				21.7	19.2
Multi-employer withdrawal liabilities	15.6				16.1				15.6	16.1
Federal net operating losses	0.9				14.3				0.9	14.3
State net operating losses	7.5				7.3				7.5	7.3
U.S. State alternative minimum tax credits	4.4				6.7				4.4	6.7
Insurance reserves	5.3				5.9				5.3	5.9
Deferred compensation	8.2				5.8				8.2	5.8
Other	10.4				5.9				10.4	5.9
Total deferred tax assets	137.5				144.3				137.5	144.3
Valuation allowance	(10)				(10.6)				(10)	(10.6)
Total Deferred tax assets, net of valuation allowance	127.5				133.7				127.5	133.7
Deferred tax liabilities:
Basis differences for property and equipment	372.4				319.2				372.4	319.2
Operating lease right of use assets	61.5				61.1				61.5	61.1
Intangibles	40.5				39.7				40.5	39.7
Lease financing	22				23.7				22	23.7
Capital Construction Fund	6.7				12.5				6.7	12.5
Investment in SSAT	7.4				7.4				7.4	7.4
Other	6.6				7.7				6.6	7.7
Total deferred tax liabilities	517.1				471.3				517.1	471.3
Deferred tax liability, net , Total	$ 389.6				$ 337.6				$ 389.6	$ 337.6

INCOME TAXES - OPERATING LOSS A

INCOME TAXES - OPERATING LOSS AND TAX CREDIT CARRYFORWARDS (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Operating Loss and Tax Credit Carryforwards
Valuation allowances	$ 10	$ 10.6
Operating loss carryforwards, not expected to benefit the entity	157.9	157.9
U.S. Federal Income Tax
Operating Loss and Tax Credit Carryforwards
Net operating losses carryforwards	7.6	71.2
State Income Tax
Operating Loss and Tax Credit Carryforwards
Net operating losses carryforwards	185.9	184.5
Alternative minimum tax credit carryforwards	4	6.7
Foreign Income Tax
Operating Loss and Tax Credit Carryforwards
Net operating losses carryforwards	$ 11.9	$ 14

INCOME TAXES - UNRECOGNIZED TAX

INCOME TAXES - UNRECOGNIZED TAX BENEFITS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of the beginning and ending amount of gross unrecognized tax benefits
Balance at beginning of the period	$ 16.4	$ 15.1	$ 15.9
Changes in tax positions of prior years, net			(0.3)
Changes in tax positions of prior years, net	2.1	2.1
Reductions for lapse of statute of limitations	(0.2)	(0.8)	(0.5)
Balance at the end	18.3	16.4	$ 15.1
Unrecognized tax benefits that, if recognized, would impact the effective rate	18.3
Interest accrued related to unrecognized tax benefits	$ 0.1	$ 0.1

PENSION AND POST-RETIREMENT P_3

PENSION AND POST-RETIREMENT PLANS - ASSET ALLOCATION (Details) - plan	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Employee benefit plans
Number of single-employer defined benefit pension funded plans	2
Pension Benefits
Employee benefit plans
Target allocation (as a percent)	100.00%
Asset allocations (as a percent)	100.00%	100.00%
One year returns (losses) on plan assets (as a percent)	12.00%
Three year returns (losses) on plan assets (as a percent)	8.70%
Five year returns (losses) on plan assets (as a percent)	9.80%
Long-term average return on plan assets since inception (as a percent)	8.50%
Pension Benefits | Domestic equity securities
Employee benefit plans
Target allocation (as a percent)	53.00%
Asset allocations (as a percent)	60.00%	59.00%
Pension Benefits | International equity securities
Employee benefit plans
Target allocation (as a percent)	15.00%
Asset allocations (as a percent)	17.00%	17.00%
Pension Benefits | Debt securities
Employee benefit plans
Target allocation (as a percent)	22.00%
Asset allocations (as a percent)	17.00%	17.00%
Pension Benefits | Real estate
Employee benefit plans
Target allocation (as a percent)	5.00%
Asset allocations (as a percent)	5.00%	6.00%
Pension Benefits | Other and cash
Employee benefit plans
Target allocation (as a percent)	5.00%
Asset allocations (as a percent)	1.00%	1.00%

PENSION AND POST-RETIREMENT P_4

PENSION AND POST-RETIREMENT PLANS - FAIR VALUE (Details) - Pension Benefits - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension and Post-retirement Plans
Total	$ 212.8	$ 194.8	$ 162.2
Fair Value Measurement
Pension and Post-retirement Plans
Total	170.9	157.3
Total plan assets	212.8	194.8
Fair Value Measurement | Cash
Pension and Post-retirement Plans
Total	3.8	6.3
Fair Value Measurement | U.S. large-cap
Pension and Post-retirement Plans
Total	71.3	62.4
Fair Value Measurement | U.S. mid- and small-cap
Pension and Post-retirement Plans
Total	54.3	49.6
Fair Value Measurement | International large-cap
Pension and Post-retirement Plans
Total	7	6.6
Fair Value Measurement | U.S. Treasuries
Pension and Post-retirement Plans
Total	12	14.1
Fair Value Measurement | Investment grade U.S. corporate bonds
Pension and Post-retirement Plans
Total	22.5	18.2
Fair Value Measurement | High-yield U.S. corporate bonds
Pension and Post-retirement Plans
Total		0.1
Fair Value Measurement | Quoted Prices in Active Markets (Level 1)
Pension and Post-retirement Plans
Total	68.9	63.9
Fair Value Measurement | Quoted Prices in Active Markets (Level 1) | Cash
Pension and Post-retirement Plans
Total	3.8	6.3
Fair Value Measurement | Quoted Prices in Active Markets (Level 1) | U.S. large-cap
Pension and Post-retirement Plans
Total	28.9	23.7
Fair Value Measurement | Quoted Prices in Active Markets (Level 1) | U.S. mid- and small-cap
Pension and Post-retirement Plans
Total	36.2	33.9
Fair Value Measurement | Significant Observable Inputs (Level 2)
Pension and Post-retirement Plans
Total	102	93.4
Fair Value Measurement | Significant Observable Inputs (Level 2) | U.S. large-cap
Pension and Post-retirement Plans
Total	42.4	38.7
Fair Value Measurement | Significant Observable Inputs (Level 2) | U.S. mid- and small-cap
Pension and Post-retirement Plans
Total	18.1	15.7
Fair Value Measurement | Significant Observable Inputs (Level 2) | International large-cap
Pension and Post-retirement Plans
Total	7	6.6
Fair Value Measurement | Significant Observable Inputs (Level 2) | U.S. Treasuries
Pension and Post-retirement Plans
Total	12	14.1
Fair Value Measurement | Significant Observable Inputs (Level 2) | Investment grade U.S. corporate bonds
Pension and Post-retirement Plans
Total	22.5	18.2
Fair Value Measurement | Significant Observable Inputs (Level 2) | High-yield U.S. corporate bonds
Pension and Post-retirement Plans
Total		0.1
Fair Value Measurement | Investment measured at NAV
Pension and Post-retirement Plans
Total	$ 41.9	$ 37.5

PENSION AND POST-RETIREMENT P_5

PENSION AND POST-RETIREMENT PLANS - STATUS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits
Change in Benefit Obligation:
Benefit obligation at beginning of year	$ 239.9	$ 217.4
Service cost	5.1	4.7	$ 4.4
Interest cost	7.9	9.3	8.6
Actuarial (gain) loss	23.9	22.2
Benefits paid, net of subsidies received	(12.5)	(12.2)
Expenses paid	(1.2)	(1.5)
Benefit obligation at end of year	263.1	239.9	217.4
Change in Plan Assets:
Balance at the beginning of the period	194.8	162.2
Actual return on plan assets	22.7	36.3
Employer contribution	9	10	0
Benefits paid, net of subsidies received	(12.5)	(12.2)
Expenses paid	(1.2)	(1.5)
Balance at the end of the period	212.8	194.8	162.2
Funded Status and Recognized Liability	(50.3)	(45.1)
Post-retirement Benefits
Change in Benefit Obligation:
Benefit obligation at beginning of year	26	22.2
Service cost	0.5	0.4	0.6
Interest cost	0.8	0.9	1
Plan participants' contributions	0.8	0.8
Actuarial (gain) loss	2.7	3.4
Benefits paid, net of subsidies received	(1.7)	(1.7)
Benefit obligation at end of year	29.1	26	$ 22.2
Change in Plan Assets:
Plan participants' contributions	0.8	0.8
Employer contribution	0.9	0.9
Benefits paid, net of subsidies received	(1.7)	(1.7)
Funded Status and Recognized Liability	(29.1)	(26)
Qualified Plan | Pension Benefits
Change in Benefit Obligation:
Benefit obligation at beginning of year	238.3
Benefit obligation at end of year	261.4	238.3
Change in Plan Assets:
Balance at the beginning of the period	192.2
Balance at the end of the period	$ 210	$ 192.2

PENSION AND POST-RETIREMENT P_6

PENSION AND POST-RETIREMENT PLANS - AMOUNTS INCLUDED IN FINANCIAL STATEMENTS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employee benefit plans
Current liabilities	$ (2.7)	$ (3.1)
Non-current liabilities, net	(82)	(73.4)
Pension Benefits
Employee benefit plans
Projected benefit obligations	263.1	239.9	$ 217.4
Fair value of plan assets at end of year	212.8	194.8	162.2
Pension Benefits | Qualified Plan
Employee benefit plans
Non-current assets	1	1
Non-current liabilities, net	(51.3)	(46.1)
Total	(50.3)	(45.1)
Net loss, net of taxes	(64.2)	(56.2)
Prior service credit, net of taxes	2.5	4.3
Total	(61.7)	(51.9)
Projected benefit obligations	261.4	238.3
Accumulated benefit obligation	260.9	237.9
Fair value of plan assets at end of year	210	192.2
Pension Benefits | Nonqualified Plan
Employee benefit plans
Current liabilities	(1.7)	(2.1)
Non-current liabilities, net	(2.6)	(2.3)
Total	(4.3)	(4.4)
Net loss, net of taxes	(0.8)	(0.6)
Prior service credit, net of taxes	0.1	0.2
Total	(0.7)	(0.4)
Post-retirement Benefits
Employee benefit plans
Projected benefit obligations	$ 29.1	26	$ 22.2
Amortization period of unrecognized gains and losses	5 years
Post-retirement Benefits | Qualified Plan
Employee benefit plans
Current liabilities	$ (1)	(1)
Non-current liabilities, net	(28.1)	(25)
Total	(29.1)	(26)
Net loss, net of taxes	(4.4)	(2.8)
Prior service credit, net of taxes	16.6	19.1
Total	$ 12.2	$ 16.3

PENSION AND POST-RETIREMENT P_7

PENSION AND POST-RETIREMENT PLANS - COMPONENTS OF NET PERIODIC BENEFIT COST (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Components of Net Periodic Benefit Cost (Benefit):
Current liabilities	$ 2.7	$ 3.1
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income, net of tax:
Amortization of net loss	9.4	(2.7)	$ (1.1)
Amortization of prior service cost	$ 4.7	$ 4.5	4.7
Qualified Pension Plans, Non-qualified Pension Plans and Post-retirement Plans
Discount rate used to determine obligation (as a percent)	1.80%	2.80%
Pension Benefits
Components of Net Periodic Benefit Cost (Benefit):
Service cost	$ 5.1	$ 4.7	4.4
Interest cost	7.9	9.3	8.6
Expected return on plan assets	(14)	(11.9)	(13.5)
Amortization of net loss	4.5	5.2	4.6
Amortization of prior service credit	(2.3)	(2.3)	(2.3)
Net periodic benefit cost (benefit)	1.2	5	1.8
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income, net of tax:
Net loss (gain)	11.4	(1.7)	7.8
Amortization of net loss	(3.4)	(3.9)	(3.5)
Amortization of prior service cost	1.7	1.7	1.7
Total recognized in other comprehensive (income) loss	9.7	(3.9)	6
Total recognized in net periodic benefit cost and other comprehensive (income) loss	$ 10.9	$ 1.1	$ 7.8
Weighted Average Assumptions:
Discount rate (as a percent)	2.50%	3.40%	4.40%
Expected return plan assets (as a percent)	7.25%	7.50%	7.50%
Rate of compensation increase (as a percent)	3.00%	3.00%	3.00%
Cash balance interest credit rate			3.01%
Qualified Pension Plans, Non-qualified Pension Plans and Post-retirement Plans
Total obligation	$ 263.1	$ 239.9	$ 217.4
Pension Benefits | Minimum
Weighted Average Assumptions:
Cash balance interest credit rate	0.75%	1.75%
Pension Benefits | Maximum
Weighted Average Assumptions:
Cash balance interest credit rate	3.25%	3.75%
Post-retirement Benefits
Components of Net Periodic Benefit Cost (Benefit):
Service cost	$ 0.5	$ 0.4	0.6
Interest cost	0.8	0.9	1
Amortization of net loss	0.5	(0.1)	1.5
Amortization of prior service credit	(3.7)	(3.8)	(3.8)
Net periodic benefit cost (benefit)	(1.9)	(2.6)	(0.7)
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income, net of tax:
Net loss (gain)	2	2.5	(4.7)
Amortization of net loss	(0.3)	0.2	(1.1)
Amortization of prior service cost	2.8	2.8	2.8
Total recognized in other comprehensive (income) loss	4.5	5.5	(3)
Total recognized in net periodic benefit cost and other comprehensive (income) loss	$ 2.6	$ 2.9	$ (3.7)
Weighted Average Assumptions:
Discount rate (as a percent)	2.70%	3.50%	4.50%
Rate of compensation increase (as a percent)	3.00%	3.00%	3.00%
Initial health care cost trend rate, Pre-65 group (as a percent)	5.30%	5.70%	6.00%
Initial health care cost trend rate, Post-65 group (as a percent)	5.40%	5.90%	6.30%
Ultimate health care cost trend rate (as a percent)	4.40%	4.40%	4.40%
Qualified Pension Plans, Non-qualified Pension Plans and Post-retirement Plans
Total obligation	$ 29.1	$ 26	$ 22.2
Qualified Plan | Pension Benefits
Qualified Pension Plans, Non-qualified Pension Plans and Post-retirement Plans
Total obligation	261.4	238.3
Amounts recognized in accumulated other comprehensive income for net loss, net of tax	(64.2)	(56.2)
Amount recognized as prior service credit, net of tax	2.5	4.3
Total	(61.7)	(51.9)
Qualified Plan | Post-retirement Benefits
Components of Net Periodic Benefit Cost (Benefit):
Current liabilities	1	1
Qualified Pension Plans, Non-qualified Pension Plans and Post-retirement Plans
Amounts recognized in accumulated other comprehensive income for net loss, net of tax	(4.4)	(2.8)
Amount recognized as prior service credit, net of tax	16.6	19.1
Total	12.2	16.3
Nonqualified Plan | Pension Benefits
Components of Net Periodic Benefit Cost (Benefit):
Current liabilities	1.7	2.1
Qualified Pension Plans, Non-qualified Pension Plans and Post-retirement Plans
Amounts recognized in accumulated other comprehensive income for net loss, net of tax	(0.8)	(0.6)
Amount recognized as prior service credit, net of tax	0.1	0.2
Total	$ (0.7)	$ (0.4)

PENSION AND POST-RETIREMENT P_8

PENSION AND POST-RETIREMENT PLANS - ESTIMATED BENEFIT PAYMENTS (Details) $ in Millions	Dec. 31, 2020USD ($)
Pension Benefits
Estimated future benefit payments
2021	$ 14
2022	14.4
2023	14.6
2024	14.7
2025	14.9
2026-2030	76.2
Total remaining future undiscounted payments due	148.8
Post-retirement Benefits
Estimated future benefit payments
2021	1
2022	1
2023	1
2024	1.1
2025	1.1
2026-2030	5.5
Total remaining future undiscounted payments due	10.7
Nonqualified Plan | Pension Benefits
Estimated future benefit payments
2021	1.7
2023	2.2
2026-2030	0.6
Total remaining future undiscounted payments due	$ 4.5

PENSION AND POST-RETIREMENT P_9

PENSION AND POST-RETIREMENT PLANS - DEFINED CONTRIBUTION PLANS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
401(K) plan
Defined Contribution Plans
Employer matching contribution (as a percent)	3.00%
Employer matching contribution expenses	$ 3	$ 2.9	$ 2.4
Profit sharing plan
Defined Contribution Plans
Profit sharing expense recorded	$ 2.2	$ 0.5	$ 1.4

PENSION AND POST-RETIREMENT _10

PENSION AND POST-RETIREMENT PLANS - MULTI-EMPLOYER DEFINED BENEFIT PLANS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Multiemployer Plans
Estimated benefit plan withdrawal obligations	$ 260
Multiemployer Health and Benefit Plans
Multiemployer Plans
Contributions of Matson	32.5	$ 32.8	$ 30
Multi-employer defined contribution pension plans
Multiemployer Plans
Contributions of Matson	$ 28.4	27.3	25.5
Multi-employer defined contribution pension plans | Orange Zone
Multiemployer Plans
Expected funding deficiency period	6 years
Multi-employer defined contribution pension plans | Minimum | Green Zone
Multiemployer Plans
Funded status of multiemployer plan (as a percent)	80.00%
Multi-employer defined contribution pension plans | Maximum | Red Zone
Multiemployer Plans
Funded status of multiemployer plan (as a percent)	65.00%
Multi-employer defined contribution pension plans | Maximum | Yellow Zone
Multiemployer Plans
Funded status of multiemployer plan (as a percent)	80.00%
Multi-employer defined contribution pension plans | Maximum | Orange Zone
Multiemployer Plans
Funded status of multiemployer plan (as a percent)	80.00%
Multi-employer defined contribution pension plans | American Radio Association Pension Fund | Green Zone
Multiemployer Plans
Contributions of Matson	$ 1	1.1	1
Multi-employer defined contribution pension plans | Hawaii Terminals Multiemployer Pension Plan | Yellow Zone
Multiemployer Plans
Contributions of Matson	5.8		5.7
Multi-employer defined contribution pension plans | Hawaii Terminals Multiemployer Pension Plan | Orange Zone
Multiemployer Plans
Contributions of Matson		5.7
Multi-employer defined contribution pension plans | Hawaii Stevedoring Multiemployer Retirement Plan | Yellow Zone
Multiemployer Plans
Contributions of Matson		4.4	4.3
Multi-employer defined contribution pension plans | Hawaii Stevedoring Multiemployer Retirement Plan | Green Zone
Multiemployer Plans
Contributions of Matson	4.6
Multi-employer defined contribution pension plans | Master Mates And Pilots Pension Plan | Green Zone
Multiemployer Plans
Contributions of Matson	3.2	3.4	3
Multi-employer defined contribution pension plans | Masters, Mates and Pilots Adjustable Pension Plan | Green Zone
Multiemployer Plans
Contributions of Matson	1.8	1.9	1.7
Multi-employer defined contribution pension plans | M E B A Pension Trust - Defined Benefit Plan | Green Zone
Multiemployer Plans
Contributions of Matson	4.1	4.3	4
Multi-employer defined contribution pension plans | OCU Pension Trust Plan | Green Zone
Multiemployer Plans
Contributions of Matson	0.2	0.2	0.2
Multi-employer defined contribution pension plans | M F O W Supplementary Pension Plan | Yellow Zone
Multiemployer Plans
Contributions of Matson	0.1
Multi-employer defined contribution pension plans | M F O W Supplementary Pension Plan | Green Zone
Multiemployer Plans
Contributions of Matson		0.1
Multi-employer defined contribution pension plans | SIU Pacific District Pension Plan | Green Zone
Multiemployer Plans
Contributions of Matson	1.3	1.5	1.2
Multi-employer defined contribution pension plans | Alaska Teamster - Employer Pension Plan | Red Zone
Multiemployer Plans
Contributions of Matson	3.3	1.9	1.9
Multi-employer defined contribution pension plans | All Alaska Longshore Pension Plan | Green Zone
Multiemployer Plans
Contributions of Matson	1.3	1.2	1
Multi-employer defined contribution pension plans | Western Conference of Teamsters Pension Plan | Green Zone
Multiemployer Plans
Contributions of Matson	1.6	1.5	1.4
Multi-employer defined contribution pension plans | O P E I U Local 153 Pension Plan | Red Zone
Multiemployer Plans
Contributions of Matson	$ 0.1	$ 0.1	$ 0.1

PENSION AND POST-RETIREMENT _11

PENSION AND POST-RETIREMENT PLANS - MULTI-EMPLOYER DEFINED CONTRIBUTION PLANS (Details) - Multi-employer defined contribution pension plans $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)plan	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Defined Contribution Plans
Number of Multiemployer Plans | plan	6
Employer contributions | $	$ 5.1	$ 5.3	$ 4.8

MULTI-EMPLOYER WITHDRAWAL LIA_3

MULTI-EMPLOYER WITHDRAWAL LIABILITIES (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Multiemployer withdrawal liability
Quarterly payments to ILA-PRSSA over an estimated period	$ 1
Estimated future benefit payments
Current portion of withdrawal liability	(10.6)	$ (10.8)
Long-term portion of withdrawal liability	52.8	54.8
Horizon | ILA-PRSSA Pension Fund
Estimated future benefit payments
2021	4.1
2022	4.1
2023	4.1
2024	4.1
2025	4.1
Thereafter	59.7
Total remaining future undiscounted payments due	80.2
Less: amount representing interest	(23.3)
Present value of remaining withdrawal liability	56.9
Current portion of withdrawal liability	(4.1)
Long-term portion of withdrawal liability	52.8
Horizon | Local 153 Fund of the OPEIU
Estimated future benefit payments
Present value of remaining withdrawal liability	$ 6.5	$ 6.7

ACCUMULATED OTHER COMPREHENSI_3

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Changes in accumulated other comprehensive income (loss) by component, net of taxes
Balance at the beginning of the period	$ 805.7	$ 755.3	$ 677.2
Amortization of prior service cost	(4.7)	(4.5)	(4.7)
Amortization of net loss (gain)	(9.4)	2.7	1.1
Other adjustments	0.2	(0.6)
Balance at the end of the period	961.2	805.7	755.3
Comprehensive Income (Loss):
Tax benefit (expense) on other comprehensive income (loss)	4.2	(0.3)	0.2
Pensions
Changes in accumulated other comprehensive income (loss) by component, net of taxes
Balance at the beginning of the period	(51.9)	(55.8)
Amortization of prior service cost	(1.8)	(1.7)
Amortization of net loss (gain)	(8)	5.6
Balance at the end of the period	(61.7)	(51.9)	(55.8)
Post Retirement
Changes in accumulated other comprehensive income (loss) by component, net of taxes
Balance at the beginning of the period	16.3	21.7
Amortization of prior service cost	(2.8)	(2.6)
Amortization of net loss (gain)	(1.3)	(2.8)
Balance at the end of the period	12.2	16.3	21.7
Non-Qualified Plans
Changes in accumulated other comprehensive income (loss) by component, net of taxes
Balance at the beginning of the period	(0.4)	(0.1)
Amortization of prior service cost	(0.1)	(0.1)
Amortization of net loss (gain)	(0.1)	(0.2)
Balance at the end of the period	(0.6)	(0.4)	(0.1)
Other
Changes in accumulated other comprehensive income (loss) by component, net of taxes
Balance at the beginning of the period	(0.9)	(0.3)
Amortization of prior service cost		(0.1)
Amortization of net loss (gain)		0.1
Foreign currency exchange	0.5
Other adjustments	(0.3)	(0.6)
Balance at the end of the period	(0.7)	(0.9)	(0.3)
Accumulated Other Comprehensive Income (Loss)
Changes in accumulated other comprehensive income (loss) by component, net of taxes
Balance at the beginning of the period	(36.9)	(34.5)	(24.9)
Amortization of prior service cost	(4.7)	(4.5)
Amortization of net loss (gain)	(9.4)	2.7
Foreign currency exchange	0.5
Other adjustments	(0.3)	(0.6)
Balance at the end of the period	$ (50.8)	$ (36.9)	$ (34.5)

EARNINGS PER-SHARE (Details)

EARNINGS PER-SHARE (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net Income
Net Income, Basic									$ 193.1	$ 82.7	$ 109
Net Income, Diluted									$ 193.1	$ 82.7	$ 109
Weighted Average Common Shares
Basic									43.1	42.8	42.7
Effect of Dilutive Securities (in shares)									0.4	0.5	0.3
Diluted (in shares)									43.5	43.3	43
Per Common Share Amount
Net income, Basic (in dollars per share)	$ 1.99	$ 1.65	$ 0.76	$ 0.09	$ 0.36	$ 0.84	$ 0.43	$ 0.29	$ 4.48	$ 1.93	$ 2.55
Effect of Dilutive Securities (in dollars per shares)									(0.04)	(0.02)	(0.02)
Net income, Diluted (in dollars per share)	$ 1.96	$ 1.63	$ 0.76	$ 0.09	$ 0.36	$ 0.84	$ 0.43	$ 0.29	$ 4.44	$ 1.91	$ 2.53

SHARE-BASED AWARDS - SUMMARY (D

SHARE-BASED AWARDS - SUMMARY (Details) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)plan$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)
Share-based expense (net of estimated forfeitures)
Total share-based expense	$ 18,800	$ 11,300	$ 12,100
Intrinsic value of options exercised	5,800	500	500
Tax benefit realized upon option exercise	3,300	2,000	2,700
Fair value of stock vested	13,100	$ 8,200	$ 10,800
Stock options
Share-based expense (net of estimated forfeitures)
Unrecognized compensation cost	$ 0
Weighted average exercise price
Outstanding, weighted average exercise price, beginning of period (in dollars per share) | $ / shares	$ 22.30
Exercised, weighted average exercise price (in dollars per share) | $ / shares	22.31
Outstanding, weighted average exercise price, end of period (in dollars per share) | $ / shares	20.84	$ 22.30
Exercisable, weighted average exercise price, end of period (in dollars per share) | $ / shares	$ 20.84
Outstanding, weighted average contractual life, end of period	1 month 6 days
Exercisable, weighted average contractual life, end of period	1 month 6 days
Outstanding, aggregate intrinsic value, end of period (in dollars)	$ 35
Exercisable, aggregate intrinsic value, end of period (in dollars)	35
Non-vested restricted stock units and performance-based equity awards
Share-based expense (net of estimated forfeitures)
Unrecognized compensation cost	$ 17,700
Unrecognized compensation cost, weighted average period for recognition	1 year 8 months 12 days
Restricted Stock Units
Share-based compensation
Options granted, weighted average grant-date fair value (in dollars per share) | $ / shares	$ 38.68
2016 Plan
Share-based compensation
Common stock initially available for future issuance (in shares) | shares	2,500
Additional shares authorized for issuance | shares	0
Number of separate incentive compensation programs | plan	4
Number of share based compensation plans within the entity's incentive compensation programs | plan	3
2016 Plan | Discretionary Grant Program
Share-based compensation
Minimum exercise price as a percentage of fair market value of common stock	100.00%
Exercisable period	3 years
Expiration Term	10 years
2016 Plan | Time-Based Restricted Stock Units | Stock Issuance Program
Share-based compensation
Vesting period of awards granted	3 years
2016 Plan | Time-Based Restricted Stock Units | Automatic Grant Program
Share-based compensation
Vesting period of awards granted	1 year
2016 Plan | Performance-Based Restricted Stock Units | Stock Issuance Program
Share-based compensation
Vesting period of awards granted	3 years
2007 Plan | Stock options
Activity in the entity's stock option plans
Outstanding, beginning of period (in shares) | shares	173
Exercised (in shares) | shares	(172)
Outstanding, end of period (in shares) | shares	1	173
Exercisable, end of period (in shares) | shares	1

SHARE-BASED AWARDS - RESTRICTED

SHARE-BASED AWARDS - RESTRICTED STOCK UNIT ACTIVITY (Details) - Restricted Stock Units shares in Thousands	12 Months Ended
	Dec. 31, 2020$ / sharesshares
Non-vested restricted stock unit activity
Outstanding, beginning of period (in shares)	778
Granted (in shares)	341
Settlement of Performance Shares (in shares)	38
Vested (in shares)	(344)
Cancelled (in shares)	(21)
Outstanding, end of period (in shares)	792
Weighted Average Grant-Date Fair Value
Outstanding, weighted average grant-date fair value, beginning of period (in dollars per share) | $ / shares	$ 33.39
Granted, weighted average grant-date fair value (in dollars per share) | $ / shares	38.68
Settlement of Performance Shares, weighted average grant-date fair value (in dollars per share) | $ / shares	36.55
Vested, weighted average grant-date fair value (in dollars per share) | $ / shares	34.86
Cancelled, weighted average grant-date fair value (in dollars per shares) | $ / shares	34.59
Outstanding, weighted average grant-date fair value, end of period (in dollars per shares) | $ / shares	$ 35.14
2007 Plan
Non-vested restricted stock unit activity
Outstanding, beginning of period (in shares)	8
Vested (in shares)	(5)
Outstanding, end of period (in shares)	3
2016 Plan
Non-vested restricted stock unit activity
Outstanding, beginning of period (in shares)	770
Granted (in shares)	341
Settlement of Performance Shares (in shares)	38
Vested (in shares)	(339)
Cancelled (in shares)	(21)
Outstanding, end of period (in shares)	789

FAIR VALUE OF FINANCIAL INSTR_3

FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash and Cash Equivalents
Restricted Cash	$ 5.3	$ 7.2	$ 4.9
Carrying value
Cash and Cash Equivalents
Cash and cash equivalents	14.4	21.2
Restricted Cash	5.3	7.2
Variable rate debt	71.8	379.1
Fixed rate debt	688.3	579.3
Fair Value Measurement
Cash and Cash Equivalents
Cash and cash equivalents	14.4	21.2
Restricted Cash	5.3	7.2
Variable rate debt	71.8	379.1
Fixed rate debt	686.7	585.9
Quoted Prices in Active Markets (Level 1) | Fair Value Measurement
Cash and Cash Equivalents
Cash and cash equivalents	14.4	21.2
Restricted Cash	5.3	7.2
Significant Observable Inputs (Level 2) | Fair Value Measurement
Cash and Cash Equivalents
Variable rate debt	71.8	379.1
Fixed rate debt	$ 686.7	$ 585.9

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES (Details) $ in Millions	Dec. 31, 2020USD ($)
Commitments, Guarantees and Contingencies
Standby letters of credit	$ 8.1
Vendor and other obligations	69.1
U.S. Customs bond
Commitments, Guarantees and Contingencies
Bonds	$ 33.2

QUARTERLY INFORMATION (Unaudi_3

QUARTERLY INFORMATION (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly information by segments
Total Operating Revenue	$ 700.1	$ 645.2	$ 524.1	$ 513.9	$ 540.7	$ 572.1	$ 557.9	$ 532.4	$ 2,383.3	$ 2,203.1	$ 2,222.8
Operating Income	117.7	98.4	51.2	13	25.4	55.2	31	17.5	280.3	129.1	163.8
Interest expense, net	(4.9)	(5.7)	(8.2)	(8.6)	(5.6)	(6.2)	(6.1)	(4.6)	(27.4)	(22.5)	(18.7)
Other income (expense), net	1.6	2.4	1.5	0.6	0.3	(0.5)	0.8	0.6	6.1	1.2	2.6
Income before Income Taxes	114.4	95.1	44.5	5	20.1	48.5	25.7	13.5	259	107.8	147.7
Income tax expense	(28.8)	(24.2)	(11.7)	(1.2)	(4.5)	(12.3)	(7.3)	(1)	(65.9)	(25.1)	(38.7)
Net Income	$ 85.6	$ 70.9	$ 32.8	$ 3.8	$ 15.6	$ 36.2	$ 18.4	12.5	$ 193.1	82.7	109
Income taxes - Discrete adjustments related to the Tax Act (1)								$ 2.9		$ (2.9)	$ 2.9
Net Income, Earnings Per Share:
Basic Earnings Per-Share: (in dollars per share)	$ 1.99	$ 1.65	$ 0.76	$ 0.09	$ 0.36	$ 0.84	$ 0.43	$ 0.29	$ 4.48	$ 1.93	$ 2.55
Diluted Earnings Per-Share: (in dollars per share)	$ 1.96	$ 1.63	$ 0.76	$ 0.09	$ 0.36	$ 0.84	$ 0.43	$ 0.29	$ 4.44	$ 1.91	$ 2.53
Ocean Transportation
Quarterly information by segments
Total Operating Revenue	$ 543.9	$ 498.3	$ 410.8	$ 400.9	$ 416.1	$ 437.2	$ 415.4	$ 397.9
Operating Income	108.1	86.5	42.3	7.9	17.8	43.9	19.7	9.4
Logistics
Quarterly information by segments
Total Operating Revenue	156.2	146.9	113.3	113	124.6	134.9	142.5	134.5
Operating Income	$ 9.6	$ 11.9	$ 8.9	$ 5.1	$ 7.6	$ 11.3	$ 11.3	$ 8.1