Financial Instruments - Summary of Fair Value and Carrying Value of Assets and Liabilities Measured on Recurring and Non-recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Time-charter swap agreement	$ 1,345	$ 0
Stock purchase warrant	916	5,164
Vessel held for sale	14,000	0
Advances to equity accounted investments	11,480	13,980
Long-term debt, including current portion	(1,044,270)	(1,164,605)
Time-charter Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Time-charter swap agreement	1,345
Warrant [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stock purchase warrant	916	5,164
Carrying Amount Asset / (Liability) [Member] \| Equity Accounted Investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Advances to equity accounted investments	11,480	13,980
Carrying Amount Asset / (Liability) [Member] \| Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, including current portion	(1,044,270)	(1,164,605)
Carrying Amount Asset / (Liability) [Member] \| Fair Value Measurements, Recurring [Member] \| Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	59,018	97,287
Carrying Amount Asset / (Liability) [Member] \| Fair Value Measurements, Recurring [Member] \| Level 2 [Member] \| Interest Rate Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap agreements	(8,425)	(10,538)
Carrying Amount Asset / (Liability) [Member] \| Fair Value Measurements, Recurring [Member] \| Level 3 [Member] \| Time-charter Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Time-charter swap agreement	1,345	0
Carrying Amount Asset / (Liability) [Member] \| Fair Value Measurements, Recurring [Member] \| Level 3 [Member] \| Warrant [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stock purchase warrant	916	5,164
Carrying Amount Asset / (Liability) [Member] \| Fair Value, Measurements, Nonrecurring [Member] \| Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Vessel held for sale	14,000	0
Fair Value Asset / (Liability) [Member] \| Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, including current portion	(1,031,173)	(1,140,135)
Fair Value Asset / (Liability) [Member] \| Fair Value Measurements, Recurring [Member] \| Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	59,018	97,287
Fair Value Asset / (Liability) [Member] \| Fair Value Measurements, Recurring [Member] \| Level 2 [Member] \| Interest Rate Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap agreements	(8,425)	(10,538)
Fair Value Asset / (Liability) [Member] \| Fair Value Measurements, Recurring [Member] \| Level 3 [Member] \| Time-charter Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Time-charter swap agreement	1,345	0
Fair Value Asset / (Liability) [Member] \| Fair Value Measurements, Recurring [Member] \| Level 3 [Member] \| Warrant [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stock purchase warrant	916	5,164
Fair Value Asset / (Liability) [Member] \| Fair Value, Measurements, Nonrecurring [Member] \| Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Vessel held for sale	$ 14,000	$ 0

Long-Term advances receivable from a party that is affiliated with the reporting entity by means of direct or indirect ownership. This does not include advances to clients.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-04.2)
-URI http://asc.fasb.org/extlink&oid=6488278&loc=d3e603758-122996

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section 45
-Paragraph 4
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6812-107765

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Amount of assets held-for-sale that are not part of a disposal group, expected to be sold within a year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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- Definition

Cash includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the customer may deposit additional funds at any time and effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid Investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Short-term investments, exclusive of cash equivalents, generally consist of marketable securities intended to be sold within one year (or the normal operating cycle if longer) and may include trading securities, available-for-sale securities, or held-to-maturity securities (if maturing within one year), as applicable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash Equivalents
-URI http://asc.fasb.org/extlink&oid=6507016

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition

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

No definition available.

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- Definition

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

+ References

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- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 20, 22
-Article 5

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