Document And Entity Information Statement [Table] Class of Stock [Axis] Class of Stock [Domain] Common Stock [Member] Common Stock Capital Rights To Purchase Common Stock [Member]. Rights To Purchase Common Stock [Member] Rights To Purchase Common Stock Statement [Line Items] Document Type Document Quarterly Report Document Period End Date Document Transition Report Entity File Number Entity Registrant Name Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Address, Address Line One Entity Address, Address Line Two Entity Address, City or Town Entity Address, State or Province Entity Address, Postal Zip Code City Area Code Local Phone Number Title of 12(b) Security Trading Symbol No Trading Symbol Flag Security Exchange Name Entity Current Reporting Status Entity Interactive Data Current Entity Filer Category Entity Small Business Entity Emerging Growth Company Entity Shell Company Entity Common Stock, Shares Outstanding Entity Central Index Key Current Fiscal Year End Date Amendment Flag Document Fiscal Period Focus Document Fiscal Year Focus CONDENSED CONSOLIDATED BALANCE SHEETS [Abstract] Assets [Abstract] ASSETS Assets, Current [Abstract] Current Assets: Cash and Cash Equivalents, at Carrying Value, Total Corporate unrestricted cash and cash equivalents Cash and cash equivalents Short-term investments Accounts Receivable, Net, Current, Total Accounts receivable, net, current Voyage receivables, net of allowance for credit losses of $144 and $52 including unbilled receivables of $244,438 and $169,610 Nontrade Receivables, Current, Total Other receivables Inventory, Net Inventories Prepaid Expense and Other Assets, Current Prepaid expenses and other current assets Assets, Current, Total Total Current Assets Property, Plant and Equipment, Net, Total Vessels and other property, less accumulated depreciation of $487,867 and $506,585 Property plant and equipment in construction. Property Plant And Equipment In Construction Vessels construction in progress Carrying amount, net of accumulated amortization, as of the balance sheet date of capitalized drydock costs performed pursuant to regulatory requirements that are expected to be recovered over the period between dry dockings, typically over periods from 2.5 to 5 years. Deferred Drydock Expenditures Net Deferred drydock expenditures, net Operating Lease, Right-of-Use Asset Operating lease right-of-use assets Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures, Total Pool working capital deposits Goodwill Goodwill, ending Goodwill, beginning Goodwill Goodwill initially recognized Other Assets Noncurrent Other assets Assets, Total Assets Total Assets Liabilities and Equity [Abstract] LIABILITIES AND EQUITY Liabilities, Current [Abstract] Current Liabilities: Accounts Payable and Other Accrued Liabilities, Current Accounts payable, accrued expenses and other current liabilities Operating Lease, Liability, Current Current portion of operating lease liabilities Current portion of operating lease liabilities Long-term Debt, Current Maturities Less current portion Current installments of long-term debt Liabilities, Current, Total Total Current Liabilities Operating Lease, Liability, Noncurrent Long-term operating lease liabilities Long-term operating lease liabilities Long-term Debt, Excluding Current Maturities Long-term debt Long-term portion Other Liabilities Other Liabilities, Noncurrent Other liabilities Liabilities, Total Total Liabilities Liabilities Commitments and Contingencies Commitments and contingencies Stockholders' Equity Attributable To Parent [Abstract] Equity: Common Stock, Value, Issued Capital - 100,000,000 no par value shares authorized; 49,520,476 and 49,404,078 Retained Earnings (Accumulated Deficit) Retained earnings Stockholder's Equity Subtotal after treasury stock value. Stockholders Equity Subtotal Stockholders Equity Subtotal Accumulated Other Comprehensive Income (Loss), Net of Tax, Total Accumulated other comprehensive loss Accumulated other comprehensive loss Stockholders Equity Attributable to Parent, Total Balance, ending Balance, beginning Total Equity Liabilities and Equity, Total Total Liabilities and Equity Allowance for doubtful accounts receivable Voyage receivables, allowance for credit losses Unbilled Contracts Receivable Unbilled voyage receivable Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Vessels and other property, accumulated depreciation Common stock, shares authorized Common stock, no par value Common stock, shares, issued Common stock, shares, outstanding Common Stock, Shares, Outstanding, Ending Balance Common Stock, Shares, Outstanding, Beginning Balance CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS [Abstract] Products and Services [Axis] Products and Services [Domain] Pool Revenue Leases [Member]. Pool Revenue Leases [Member] Pool revenues Time and Bareboat Charter Leases [Member]. Time and Bareboat Charter Leases [Member] Time charter revenues Voyage Charter Leases [Member]. Voyage Charter Leases [Member] Voyage charter revenues Revenues [Abstract] Shipping Revenues: Revenues, Total Shipping revenues Shipping revenues The total amount of other operating revenue, the components of which are not separately disclosed on the income statement, from items that are associated with the entity's normal revenue producing operation. Other Operating Revenue Other operating revenues Operating Expenses Operating Expenses: Expenses associated with operating vessels which are attributable to particular voyages such as port and canal charges, fuel (bunker) expenses, and brokerage commissions payable to unaffiliated third parties. Voyage Expenses Less: Voyage expenses Voyage expenses Direct vessel operating expenses, which includes crew costs, provisions, deck and engine stores, lubricating oil, insurance and maintenance and repairs, incurred during the reporting period. Vessel expenses Vessel expenses Operating lease, cost Charter hire expenses Depreciation, Depletion and Amortization, Total Depreciation and amortization General and Administrative Expense, Total General and administrative expenses General and administrative Other Cost and Expense, Operating Other operating expenses Total other operating expenses Gain (Loss) on Disposition of Assets Loss/(gain) on disposal of vessels and other assets, net (Loss)/gain on disposal of vessels and other assets, net Costs and Expenses, Total Total operating expenses Operating Income (Loss), Total Income from vessel operations Business Combination, Achieved in Stages, Preacquisition Equity Interest in Acquiree, Remeasurement, Gain (Loss) Non-cash holding gain recognized Holding gain on previously held equity interest Operating Income loss excluding equity in income (loss) of affiliated companies. Operating Income Loss Excluding Equity In Income Loss Of Affiliated Companies Operating income Other Nonoperating Income (Expense) Other income Other income Income (loss) before interest expense, reorganization items and taxes during the period. Income Loss Before Interest Expense, Reorganization Items and Taxes Income before interest expense Interest Expense, Total Interest expense Interest expense Interest expense Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest Income before income taxes Income before income taxes Income tax expense (benefit) Income tax benefit Net income Weighted Average Number Basic and Diluted Shares Outstanding [Abstract] Weighted Average Number of Common Shares Outstanding: Weighted Average Number of Shares Outstanding, Basic Basic Weighted-average common shares outstanding, basic Weighted Average Number of Shares Outstanding, Diluted Weighted-average common shares outstanding, diluted Diluted EARNINGS PER COMMON SHARE [Abstract] Per Share Amounts: Earnings Per Share, Basic Basic net income per share Earnings Per Share, Diluted Diluted net income per share venues earned from Pools that are equity method investments. Equity Method Investment Summarized Financial Information Shipping Pool Revenue Pool revenues, received from companies accounted for by the equity method CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract] Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net income Other Comprehensive (Loss)Income, Net Of Tax Other comprehensive loss, net of tax: Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Net change in foreign currency translation Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax Net change in unrealized losses on cash flow hedges Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract] Defined benefit pension and other postretirement benefit plans: Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost (Credit) Arising During Period, Net of Tax Net change in unrecognized prior service costs Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Net of Tax Net change in unrecognized actuarial losses Other Comprehensive Income (Loss), Net of Tax, Total Other comprehensive loss Other comprehensive loss, net of tax Comprehensive Income (Loss), Net of Tax, Attributable to Parent, Total Comprehensive income CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS [Abstract] Cash Flows From Operating Activities Cash Flows from Operating Activities: Items Included In Net Loss Not Affecting Cash Flows Items included in net income not affecting cash flows: Amortization of financing costs and discounts Amortization of debt discount and other deferred financing costs Share-based Compensation, Total Stock compensation Other Noncash Income (Expense), Total Other - net n/a Investing and Financing Activities Items Included In Net Income Loss [Abstract] Items included in net income related to investing and financing activities: Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property Gain on disposal of vessels and other assets, net Gain (loss) on disposition of property Income (loss) from equity method investments Holding gain on previously held equity interest Holding gain on previously held equity interest Amounts paid for drydock costs performed pursuant to regulatory requirements. Payments For Drydocking Payments for drydocking Payments for drydocking Proceeds from Insurance Settlement, Operating Activities Insurance claims proceeds related to vessel operations Increase (Decrease) In Operating Capital [Abstract] Changes in operating assets and liabilities: Increase (Decrease) in Receivables (Increase)/decrease in voyage receivables Increase (Decrease) in Deferred Revenue Decrease in deferred revenue Increase (Decrease) in Operating Liabilities Net change in other receivables, inventories, prepaid expenses and other current assets, accounts payable, accrued expenses and other current and long-term liabilities Net Cash Provided by (Used in) Operating Activities, Continuing Operations, Total Net cash provided by operating activities Cash Flows From Investing Activities Cash Flows from Investing Activities: The cash outflow associated with the acquisition of vessels and vessels improvements. Payment to Acquire Vessels and Vessels Improvements Expenditures for vessels, vessel improvements and vessels under construction Payments to acquire vessels Security deposits for sale of vessels. Security Deposits for Sale of Vessels Security deposits returned for vessel exchange transactions Proceeds from costs of sale of property plant and equipment. Proceeds From Costs Sale of Property Plant and Equipment Proceeds from disposal of vessels and other property Payments to Acquire Other Property, Plant, and Equipment Expenditures for other property Payments to Acquire Equity Method Investments Cash consideration paid for the purchase of equity method investment, net of cash acquired Cash paid Payments to Acquire Restricted Certificates of Deposit Investments in short-term time deposits Proceeds from Annuities and Investment Certificates Proceeds from maturities of short-term time deposits Proceeds from payments to pool working capital deposits. Proceeds From Payments To Pool Working Capital Deposits Pool working capital deposits Net Cash Provided by (Used in) Investing Activities, Continuing Operations, Total Net cash (used in)/provided by investing activities Cash Flows From Financing Activities Cash Flows from Financing Activities: Proceeds from Issuance of Long-term Debt Borrowings on nonrevolving credit facility debt Repayments of Other Long-Term Debt Repayments of nonrevolving credit facility debt Proceeds from Long-term Lines of Credit Borrowings on revolving credit facilities Amount of repayments on revolving credit facilities. Repayments on Revolving Credit Facilities Repayments on revolving credit facilities Payments of sale and leaseback financing. Payments of Sale And Leaseback Financing Payments on sale and leaseback financing Payments of Debt Issuance Costs Payments of deferred financing costs Payments of dividends Cash dividends paid Payments of dividends Payments Related to Tax Withholding for Share-based Compensation Cash paid to tax authority upon vesting or exercise of stock-based compensation Net Cash Provided by (Used in) Financing Activities, Continuing Operations Net cash used in financing activities Cash and Cash Equivalents, Period Increase (Decrease), Total Net increase/(decrease) in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash and cash equivalents at end of period Cash and cash equivalents at beginning of year CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY [Abstract] Equity Components [Axis] Equity Component [Domain] Parent [Member] Retained Earnings / (Accumulated deficit) [Member] Retained Earnings Accumulated Other Comprehensive Loss [Member] Accumulated Other Comprehensive Loss Restricted Stock Restricted Stock Units (RSUs) [Member] Restricted Stock Units (RSUs) Adjustments to Additional Paid in Capital, Dividends in Excess of Retained Earnings Dividends Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation Common stock withheld related to net share settlement of equity awards Stock Granted, Value, Share-based Compensation, Net of Forfeitures Compensation relating to stock awards Adjustments to Additional Paid in Capital, Share-based Compensation and Exercise of Stock Options Compensation relating to stock options BASIS OF PRESENTATION [Abstract] Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] BASIS OF PRESENTATION Business Combination [Abstract] Business Combination [Text Block] BUSINESS COMBINATIONS SIGNIFICANT ACCOUNTING POLICIES [Abstract] Basis of Presentation and Significant Accounting Policies [Text Block] SIGNIFICANT ACCOUNTING POLICIES Earnings Per Share [Text Block] EARNINGS PER COMMON SHARE BUSINESS AND SEGMENT REPORTING [Abstract] Segment Reporting Disclosure [Text Block] BUSINESS AND SEGMENT REPORTING VESSELS [Abstract] Property, Plant and Equipment Disclosure [Text Block] VESSELS GOODWILL [Abstract] Goodwill and Intangible Assets Disclosure [Text Block] GOODWILL VARIABLE INTEREST ENTITIES (VIEs) [Abstract] Variable Interest Entity Disclosure [Text Block] VARIABLE INTEREST ENTITIES (VIEs) FAIR VALUE OF FINANCIAL INSTRUMENTS, DERIVATIVES AND FAIR VALUE DISCLOSURES [Abstract] Fair Value Disclosures [Text Block] FAIR VALUE OF FINANCIAL INSTRUMENTS, DERIVATIVES AND FAIR VALUE DISCLOSURES DEBT [Abstract] Debt Disclosure [Text Block] DEBT CAPITAL STOCK AND STOCK COMPENSATION [Abstract] Shareholders Equity and Share-based Payments [Text Block] CAPITAL STOCK AND STOCK COMPENSATION ACCUMULATED OTHER COMPREHENSIVE LOSS [Abstract]