The actual hull coverage ratio of the Company as at period end.

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The minimum liquidity required by covenants of certain debt currently held by the company. Liquidity is defined as cash, cash equivalents and undrawn committed revolving credit lines with at least six months to maturity.

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The minimum free liquidity and undrawn revolving credit line required by covenants of certain debt currently held by the Company, as a percentage of total debt.

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Weighted average discount rate for finance lease calculated at point in time.

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Period between issuance and maturity of long-term debt, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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The value (monetary amount) of the award the plaintiff seeks in the legal matter.

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A description of the terms of the lease(s) related to the assets being leased-back in connection with the transaction involving the sale of property to another party and the lease of the property back to the seller.

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Operating Leases and Obligations Related to Finance Leases - Finance Leases Additional Information (Details) $ in Millions	1 Months Ended	6 Months Ended	9 Months Ended
	Nov. 30, 2021	Sep. 30, 2021 USD ($) vessel valuators	Sep. 30, 2021 USD ($) vessel lessor valuators	Nov. 03, 2021 vessel	Sep. 06, 2021 vessel	Feb. 05, 2021 vessel	Dec. 31, 2020	Sep. 30, 2020 vessel
Finance Leased Assets [Line Items]
Number of lessors \| lessor			1
Lessee, sales-type lease, number of vessels repurchased			8
Minimum liquidity covenant requirement \| $		$ 35.0	$ 35.0
Minimum liquidity as a percentage of consolidated debt covenant requirement		5.00%	5.00%
Debt Covenant Minimum Free Liquidity And Undrawn Revolving Credit Line \| $		$ 35.0	$ 35.0
Finance Lease, Weighted Average Discount Rate, Percent		5.30%	5.30%				7.80%
Debt Covenant Minimum Hull Coverage Ratio			100.00%
Subsequent Event [Member]
Finance Leased Assets [Line Items]
Sale Leaseback Transaction, Lease Terms	seven
Debt Covenant Minimum Hull Coverage Ratio	105.00%
Aframax Tanker
Finance Leased Assets [Line Items]
Number Of Vessels		1	1		1
Aframax Tanker \| Subsequent Event [Member]
Finance Leased Assets [Line Items]
Number Of Vessels				1
Suezmax Tankers
Finance Leased Assets [Line Items]
Number Of Vessels								3
Aframax Tankers
Finance Leased Assets [Line Items]
Number Of Vessels						2
Minimum [Member]
Finance Leased Assets [Line Items]
Number of Third Party Valuators \| valuators		1	1
Loss Contingency, Damages Sought, Value \| $		$ 7.3
Sale Leaseback Transaction, Lease Terms			eight
Actual Hull Coverage Ratio		104.00%	104.00%				121.00%
Long-term Debt, Term		6 months	6 months
Maximum
Finance Leased Assets [Line Items]
Sale Leaseback Transaction, Lease Terms			12
Actual Hull Coverage Ratio		130.00%	130.00%				156.00%
July 2017 Sale Leaseback [Member] \| Suezmax Tankers
Finance Leased Assets [Line Items]
Number of Vessels with Purchase Option		4	4
November 2018 Sale leaseback Transaction [Member] \| Suezmax and LR2 Tankers
Finance Leased Assets [Line Items]
Number of Vessels with Purchase Option		2	2
July 2017, November 2018 and September 2021 Sale Leaseback Transaction \| Aframax Suezmax and LR2 Tankers
Finance Leased Assets [Line Items]
Number of Vessels with Purchase Option		10	10
Number Of Vessels		10	10
September 2021 sale Leaseback \| Suezmax and Aframax Tankers
Finance Leased Assets [Line Items]
Number of Vessels with Purchase Option		4	4
Number Of Vessels		4	4
November 2021 Sale Leaseback \| Aframax Tankers \| Subsequent Event [Member]
Finance Leased Assets [Line Items]
Number Of Vessels				4
Finance Lease Obligations [Member]
Finance Leased Assets [Line Items]
Minimum liquidity covenant requirement \| $		$ 35.0	$ 35.0
Minimum liquidity as a percentage of consolidated debt covenant requirement		5.00%	5.00%
Debt Covenant Minimum Free Liquidity And Undrawn Revolving Credit Line \| $		$ 35.0	$ 35.0
Finance Lease Obligations [Member] \| Minimum [Member]
Finance Leased Assets [Line Items]
Long-term Debt, Term		6 months	6 months
Finance Lease Obligations [Member] \| July 2017 and November 2018 Sale leaseback transaction \| Aframax Suezmax and LR2 Tankers
Finance Leased Assets [Line Items]
Number Of Vessels		6	6
Finance Lease Obligations [Member] \| September 2021 sale Leaseback \| Suezmax and Aframax Tankers
Finance Leased Assets [Line Items]
Number Of Vessels		4	4