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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Amounts due from an entity in which the reporting entity shares joint control with another party or group, due after 1 year (or 1 business cycle).

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Present value of lessee's discounted obligation for lease payments from finance lease.

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Fair value as of the balance sheet date of all derivative liabilities not designated as hedging instruments.

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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.

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Amount of lessee's right to use underlying asset under operating lease.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Financial Instruments - Summary of Fair Value and Carrying Value of Assets and Liabilities Measured on Recurring and Non-recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash, cash equivalents and restricted cash (note 16)	$ 66,334	$ 103,146	$ 128,995	$ 96,790
Freight forward agreements	571	289
Operating Lease, Right-of-Use Asset	10,334	2,529
Vessels and equipment (note 15)	1,073,465	1,104,742
Short-term Debt	(20,000)	(10,000)
Long-term debt, including current portion (note 6)	(377,529)	(242,961)
Obligations related to finance leases, including current portion (note 7)	(233,816)	(360,043)
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Freight forward agreements	571	289
Advances to equity-accounted joint venture	3,780	5,280
Reported Value Measurement [Member] \| Interest rate swap agreement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Freight forward agreements	301	(289)
Reported Value Measurement [Member] \| Forward freight agreements
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Freight forward agreements	270
Level 2 \| Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt	(20,000)	(10,000)
Long-term debt, including current portion (note 6)	(377,529)	(242,961)
Obligations related to finance leases, including current portion (note 7)	(233,816)	(360,043)
Level 2 \| Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term Debt	(20,000)	(10,000)
Long-term debt, including current portion (note 6)	(382,152)	(248,738)
Obligations related to finance leases, including current portion (note 7)	(247,130)	(411,740)
Fair Value, Recurring [Member] \| Level 1 \| Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash, cash equivalents and restricted cash (note 16)	66,334	103,146
Fair Value, Recurring [Member] \| Level 1 \| Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash, cash equivalents and restricted cash (note 16)	66,334	103,146
Fair Value, Recurring [Member] \| Level 2 \| Reported Value Measurement [Member] \| Interest rate swap agreement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap agreement	(120)	(886)
Fair Value, Recurring [Member] \| Level 2 \| Reported Value Measurement [Member] \| Forward freight agreements
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Freight forward agreements	270	0
Fair Value, Recurring [Member] \| Level 2 \| Estimate of Fair Value Measurement [Member] \| Interest rate swap agreement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap agreement	(120)	(886)
Fair Value, Recurring [Member] \| Level 2 \| Estimate of Fair Value Measurement [Member] \| Forward freight agreements
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Freight forward agreements	270	0
Fair Value, Nonrecurring [Member] \| Level 2 \| Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Operating Lease, Right-of-Use Asset	0	1,799
Vessels and equipment (note 15)	0	59,250
Assets held for sale(note 15)	12,740	31,680
Fair Value, Nonrecurring [Member] \| Level 2 \| Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Operating Lease, Right-of-Use Asset	0	1,799
Vessels and equipment (note 15)	0	59,250
Assets held for sale(note 15)	$ 12,740	$ 31,680