Debt instrument, amortization, quarterly percentage of original principal amount.

No definition available.

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- Definition

Debt instrument, commitment fee, if exposure is greater or equal to 50%.

+ References

No definition available.

+ Details

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- Definition

Debt instrument, convenant amount maximum if increase requested.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Debt instrument, covenant threshold related to net cash proceeds from asset sales.

+ References

No definition available.

+ Details

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- Definition

Debt instrument, covenant related to base amount available.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt instrument, maximum amount related to increase in borrowings.

+ References

No definition available.

+ Details

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Namespace Prefix:	osgiq_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Early Repayment Of Lines of Credit

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Mandatory prepayment of debt.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of reorganization items related to debtor-in-possession facility financing costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 852
-SubTopic 10
-Section 55
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=34712771&loc=d3e56145-112766

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-Topic 852
-SubTopic 10
-Section 45
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=64805424&loc=d3e55730-112764

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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- Details

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- Details

Name:	us-gaap_VariableRateAxis=osgiq_ThirtyDayLondonInterbankOfferedRateLiborMember
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- Details

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- Details

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- Details

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- Details

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- Details

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DEBT (Exit Financing Facilities) (Narrative) (Details) - USD ($)			3 Months Ended	12 Months Ended
	May 16, 2016	Aug. 05, 2014	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Mar. 29, 2010
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage							8.125%
Prepayment of debt	$ 20,000,000
Long-term debt				$ 448,936,000	$ 525,082,000
Debtor reorganization items, debtor-in-possession facility financing costs						$ 642,000
Parent Company [Member]
Debt Instrument [Line Items]
Long-term debt				685,000	80,896,000
Exit Financing Facilities [Member]
Debt Instrument [Line Items]
Debt instrument, covenant related to base available amount				0	0
Debt instrument, interest rate, stated percentage		2.00%
Commitment fee percentage		0.50%
Exit Financing Facilities [Member] \| 1-Month London Interbank Offered Rate LIBOR [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		1.00%
Exit Financing Facilities [Member] \| Federal Funds Effective Swap Rate [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		0.50%
OBS ABL Facility [Member]
Debt Instrument [Line Items]
Debt instrument, maximum amount related to increase in borrowings		$ 25,000,000
Debt instrumnet, suppressed availability minimum amount		$ 10,000,000
Debt instrument, commitment fee, if exposure is greater or equal to 50%		0.375%
OBS Term Loan
Debt Instrument [Line Items]
Debt instrument, maximum amount related to increase in borrowings		$ 75,000,000
Debt instrument, amortization, quarterly percentage of original principal amount		1.00%
Debt instrument, convenant threshold related to net cash proceeds from asset sales				5,000,000
Mandatory prepayment of debt					27,000,000
Long-term debt				448,251,000	$ 444,186,000
Secured Debt [Member] \| OBS ABL Facility [Member]
Debt Instrument [Line Items]
Debt instrument, face amount				75,000,000
Long-term debt				72,000
Secured Debt [Member] \| OBS Term Loan
Debt Instrument [Line Items]
Debt instrument, face amount				$ 603,000,000
Scenario, Forecast [Member] \| OBS Term Loan
Debt Instrument [Line Items]
Mandatory prepayment of debt			$ 28,165,000