Fair Value of Financial Instruments, Derivatives and Fair Value Disclosures (Details 1) (Interest Rate Cap [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Other Assets [Member]
Derivative Instruments In Hedges Long Term Portion Assets At Fair Value	$ 927	$ 2,115
Derivative Instruments in Hedges, Assets, at Fair Value	927	2,115
Other Liabilities [Member]
Derivative Instruments In Hedges Long Term Portion Liabilities At Fair Value	0	0
Derivative Instruments in Hedges, Liabilities, at Fair Value	$ 0	$ 0

Fair value of non current derivative assets designated as hedging instruments. Includes instruments designated as cash flow hedges, fair value hedges, and hedges of net investments in foreign operations.

No definition available.

+ Details

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Period Type:	instant

- Definition

Fair value of non current derivative liabilities designated as hedging instruments. Includes instruments designated as cash flow hedges, fair value hedges, and hedges of net investments in foreign operations.

+ References

No definition available.

+ Details

Name:	osgiq_DerivativeInstrumentsInHedgesLongTermPortionLiabilitiesAtFairValue
Namespace Prefix:	osgiq_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Aggregate fair value of all derivative assets designated as hedging instruments. Includes instruments designated as cash flow hedges, fair value hedges, and hedges of net investments in foreign operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13433-108611

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- Definition

Aggregate fair value of all derivative liabilities designated as hedging instruments. Includes instruments designated as cash flow hedges, fair value hedges, and hedges of net investments in foreign operations.

+ References

+ Details

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