Equity Method Investments (Details Textual) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended		9 Months Ended	12 Months Ended	1 Months Ended			9 Months Ended			12 Months Ended	9 Months Ended		9 Months Ended			1 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Aug. 29, 2013	Sep. 30, 2014 Ti Asia Vessel [Member]	Dec. 31, 2013 Ti Asia Vessel [Member]	Nov. 30, 2004 Qatar Gas Transport Company Limited Nakilat Joint Venture [Member]	Sep. 30, 2014 Qatar Gas Transport Company Limited Nakilat Joint Venture [Member] Liquid Natural Gas Carrier Vessel [Member]	Dec. 31, 2013 Qatar Gas Transport Company Limited Nakilat Joint Venture [Member] Liquid Natural Gas Carrier Vessel [Member]	Sep. 30, 2014 Qatar Gas Transport Company Limited Nakilat Joint Venture [Member] Liquid Natural Gas Carrier Vessel [Member] Minimum [Member]	Sep. 30, 2014 Qatar Gas Transport Company Limited Nakilat Joint Venture [Member] Liquid Natural Gas Carrier Vessel [Member] Maximum [Member]	Sep. 30, 2014 Qatar Gas Transport Company Limited Nakilat Joint Venture and Euronav Nv Joint Venture [Member] Liquid Natural Gas Carrier Vessel [Member]	Dec. 31, 2013 Qatar Gas Transport Company Limited Nakilat Joint Venture and Euronav Nv Joint Venture [Member] Liquid Natural Gas Carrier Vessel [Member]	Sep. 30, 2014 Euronav Nv Joint Venture [Member]	Dec. 31, 2013 Euronav Nv Joint Venture [Member]	Sep. 30, 2014 Euronav Nv Joint Venture [Member] Minimum [Member]	Sep. 30, 2014 Euronav Nv Joint Venture [Member] Maximum [Member]	Sep. 30, 2014 Alaska Tanker Company LLC [Member]	Nov. 30, 2004 Liquid Natural Gas Carrier Vessel [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage													50.00%				37.50%	49.90%
Equity Method Investment, Description Of Principal Activities	operates four LNG Carriers												Maersk Oil Qatar AS (MOQ) awarded two service contracts to a joint venture between OSG and Euronav NV
Line of Credit Facility, Amount Outstanding											$ 724,280	$ 750,576	$ 151,646	$ 196,499
Debt Instrument, Periodic Payment		6,250
Debt Instrument, Date of First Required Payment		Nov. 30, 2013
Debt Instrument, Interest Rate, Basis for Effective Rate		50 basis points
Notional Amount of Interest Rate Cash Flow Hedge Derivatives											701,822	727,663	254,308	304,472
Derivative, Fixed Interest Rate											4.90%		3.90%
Interest Rate Cash Flow Hedge Liability at Fair Value							109,900	108,725					15,170	22,083
Storage Volume						four 216,200 cbm
Initial Term Of Contract																		25 years
Derivative, Maturity Date									Jul. 01, 2022	Nov. 30, 2022					Jul. 01, 2017	Sep. 30, 2017
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid			45,000
Effective Portion of Gain/(Loss) Reclassified from Accumulated Other Comprehensive Loss				3,333	5,064						54,794	54,199
Debt Instrument Final Payment		1,250
Guarantor Obligations, Liquidation Proceeds, Percentage													50.00%
Debt Instrument Date Of Final Required Payment		Aug. 31, 2015
Guaranty Assets	$ 0	$ 0