Debt (Sinosure Credit Facility) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019 USD ($)	Jul. 01, 2020	Jun. 30, 2020	Dec. 31, 2018 USD ($)
Seaways Holding Company [Member] | Scenario, Plan [Member]
Debt instrument interest expense coverage ratio		2.50	2.25
Sinosure Credit Facility [Member]
Long-term debt	$ 273,239			$ 290,620
Debt instrument covenant minimum security coverage percentage of aggregate loan principal	135.00%
Debt instrument maximum consolidated leverage ratio	0.60%
Debt instrument minimum consolidated liquidity unrestricted consolidated cash and cash equivalents	$ 25,000
Debt instrument minimum consolidated liquidity total consolidated cash and cash equivalents	$ 50,000
Debt instrument covenant percentage of total indebtedness	5.00%
Debt instrument property aggregate covenant	$ 9,000
Debt instrument per piece of property covenant	$ 1,500
Debt instrument, covenant compliance	The Sinosure Credit Facility also requires the Company to comply with a number of covenants, including the delivery of quarterly and annual financial statements, budgets and annual projections; maintaining required insurances; compliance with laws (including environmental); compliance with the Employee Retirement Income Security Act of 1974 ("ERISA"); maintenance of flag and class of the collateral vessels; restrictions on consolidations, mergers or sales of assets; limitations on liens; limitations on issuance of certain equity interests; limitations on transactions with affiliates; and other customary covenants and related provisions.
Sinosure Credit Facility [Member] | Seaways Holding Company [Member]
Debt instrument interest expense coverage ratio	2.00