Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Cap rate on an interest rate derivative such as an interest rate cap or collar. If market rates exceed the cap rate, a payment or receipt is triggered on the contract.

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The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of an intangible asset (excluding goodwill) to fair value.

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The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

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The increase (decrease) during the reporting period in the value of expenditures made during the current reporting period for benefits that will be received over a period of years. Deferred charges differ from prepaid expenses in that they usually extend over a long period of time and may or may not be regularly recurring costs of operation.

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The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

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FAIR VALUE OF FINANCIAL INSTRUMENTS, DERIVATIVES AND FAIR VALUE DISCLOSURES (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Feb. 05, 2018
Fair Value Of Financial Instruments Derivatives And Fair Value Disclousres [Line Items]
Restricted cash and cash equivalents	$ 15,844			$ 275	$ 15,844
Impairment of intangible assets (excluding goodwill)				5,878
Increase (decrease) in deferred charges			$ (3,873)
Impairment of long-lived assets held-for-use				$ 5,878	$ 104,405	$ 0
Finite-Lived intangible asset, useful Life				9 years
OSG Bulk Ships, Inc (OBS) [Member] \| Interest Rate Cap [Member]
Fair Value Of Financial Instruments Derivatives And Fair Value Disclousres [Line Items]
Derivative, notional amount				$ 375,000
Derivative, cap interest rate				2.50%
Maximum [Member] \| OSG Bulk Ships, Inc (OBS) [Member] \| Interest Rate Cap [Member] \| Subsequent Event [Member]
Fair Value Of Financial Instruments Derivatives And Fair Value Disclousres [Line Items]
Derivative, cap interest rate							3.00%
7 ATBs [Member]
Fair Value Of Financial Instruments Derivatives And Fair Value Disclousres [Line Items]
Impairment of long-lived assets held-for-use		$ 97,782
One Articulated Tug Barges [Member]
Fair Value Of Financial Instruments Derivatives And Fair Value Disclousres [Line Items]
Impairment of long-lived assets held-for-use	$ 6,623
Customer Relationships [Member]
Fair Value Of Financial Instruments Derivatives And Fair Value Disclousres [Line Items]
Finite-Lived intangible asset, useful Life				20 years