Derivative Instruments - Location and Fair Value Amounts of Derivative Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Current portion of derivative assets (note 7)	$ 116	$ 875
Derivative assets (note 7)	2,920	4,538
Accrued liabilities	(149)	(921)
Current portion of derivative liabilities	(265)	(1,108)
Interest rate swap agreements
Derivatives, Fair Value [Line Items]
Current portion of derivative assets (note 7)	89
Derivative assets (note 7)	2,920	4,251
Accrued liabilities	(118)	(254)
Current portion of derivative liabilities	(265)	(1,108)
Stock purchase warrant
Derivatives, Fair Value [Line Items]
Derivative assets (note 7)		287
Time-charter swap agreement
Derivatives, Fair Value [Line Items]
Current portion of derivative assets (note 7)		875
Accrued liabilities	(21)	$ (667)
Forward freight agreements
Derivatives, Fair Value [Line Items]
Current portion of derivative assets (note 7)	27
Accrued liabilities	$ (10)

Accrued Derivative Liabilities Current

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- Definition

Fair value, after the effects of master netting arrangements, of a financial asset or other 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.

+ References

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- Definition

Fair value as of the balance sheet date of derivative instrument not designated as hedging instrument and classified as an asset.

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- Definition

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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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

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