Contribution of amount towards share of a bank guarantee to finance.

No definition available.

Name:	ish_AmountContributedTowardsBankGuarantee
Namespace Prefix:	ish_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount paid to an equity-method investee during the period for working capital purposes.

+ References

No definition available.

+ Details

Name:	ish_ContributionToWorkingCapitalOfEquityInvestee
Namespace Prefix:	ish_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Dividend Received

+ References

No definition available.

+ Details

Name:	ish_DividendReceived
Namespace Prefix:	ish_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents interest rate stated for notes receivable.

+ References

No definition available.

+ Details

Name:	ish_NotesReceivableInterestRateStatedPercentage
Namespace Prefix:	ish_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of vessels affected by stock issuance to unaffiliated co-investor

+ References

No definition available.

+ Details

Name:	ish_NumberOfVesselsAffectedByStockIssuanceToUnaffiliatedCoInvestor
Namespace Prefix:	ish_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of Vessels Contracted To Build

+ References

No definition available.

+ Details

Name:	ish_NumberOfVesselsContractedToBuild
Namespace Prefix:	ish_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of Vessels Employed On Long-Term Bareboat Charters

+ References

No definition available.

+ Details

Name:	ish_NumberOfVesselsEmployedOnLongTermBareboatCharters
Namespace Prefix:	ish_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of vessels owned or operated by the entity as of balance sheet date.

+ References

No definition available.

+ Details

Name:	ish_NumberOfVesselsOwnedOrOperated
Namespace Prefix:	ish_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage held by unaffiliated owner in a company in which we held remaining portion.

+ References

No definition available.

+ Details

Name:	ish_PercentageHeldByUnaffiliatedOwner
Namespace Prefix:	ish_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents percentage of funded cost treated as loan by equity investor.

+ References

No definition available.

+ Details

Name:	ish_PercentageOfCostTreatedAsLoanToRelatedPartyByEquityInvestor
Namespace Prefix:	ish_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of funded cost of the terminal improvements by equity investor.

+ References

No definition available.

+ Details

Name:	ish_PercentageOfFundedCostOfTerminalImprovements
Namespace Prefix:	ish_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents percentage of funded cost treated as capital contribution by equity investor.

+ References

No definition available.

+ Details

Name:	ish_PercentageOfFundedCostTreatedAsCapitalContributionByEquityInvestor
Namespace Prefix:	ish_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of equity interests acquired by unaffiliated owner.

+ References

No definition available.

+ Details

Name:	ish_PercentageOfInterestAcquiredByUnaffiliatedOwner
Namespace Prefix:	ish_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

An amount representing an agreement for an unconditional promise by the maker to pay the Company (holder) a definite sum of money within one year from the balance sheet date (or the normal operating cycle, whichever is longer), net of any write-downs taken for collection uncertainty on the part of the holder.

+ References

No definition available.

+ Details

Name:	ish_PromissoryNotesReceivableOne
Namespace Prefix:	ish_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

+ References

No definition available.

+ Details

Name:	ish_PromissoryNotesReceivableTwo
Namespace Prefix:	ish_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the repayment period of the note receivable.

+ References

No definition available.

+ Details

Name:	ish_TermOfNoteReceivable
Namespace Prefix:	ish_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of the required periodic payments including both interest and principal payments.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 470

-Section 50

-Paragraph 3

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

+ Details

Name:	us-gaap_DebtInstrumentPeriodicPayment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Aggregate amount of receivables to be collected from related parties where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth, at the financial statement date. which are usually due after one year (or one business cycle).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(k)(1))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 850

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph k

-Subparagraph 1

-Article 4

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.11)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 11

-Article 5

+ Details

Name:	us-gaap_DueFromRelatedPartiesNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents the aggregate cost of investments accounted for under the equity method of accounting.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.12)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 12

-Article 5

+ Details

Name:	us-gaap_EquityMethodInvestmentAggregateCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Difference between amount at which an investment accounted for under the equity method of accounting is carried (reported) on the balance sheet and amount of underlying equity in net assets the reporting Entity has in the investee.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents disclosure of the amount of dividends or other distributions received from unconsolidated subsidiaries, certain corporate joint ventures, and certain noncontrolled corporation; these investments are accounted for under the equity method of accounting. This element excludes distributions that constitute a return of investment, which are classified as investing activities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 13

-Article 5

+ Details

Name:	us-gaap_EquityMethodInvestmentDividendsOrDistributions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The net realized gain (loss) on investments sold during the period, not including gains (losses) on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity, which, for cash flow reporting, is a component of proceeds from investing activities.

+ References

+ Details

Name:	us-gaap_GainLossOnSaleOfInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireEquityMethodInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash inflow from the sale of an investment interest in a joint venture that the reporting entity has not previously accounted for using consolidation or the equity method of accounting.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 12

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3179-108585

+ Details

Name:	us-gaap_ProceedsFromDivestitureOfInterestInJointVenture
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=ish_MiniBulkersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ish_BrattholmenShippingLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ish_OsloBulkAsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ish_OsloBulkHoldingPteLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ish_RtiLogisticsLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ish_SaltholmenShippingLtdMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ish_TerminalesTransgolfoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Unconsolidated Entities (Narrative) (Details) (USD $)	1 Months Ended		12 Months Ended				1 Months Ended	12 Months Ended	1 Months Ended	3 Months Ended		12 Months Ended
Unconsolidated Entities (Narrative) (Details) (USD $)	Nov. 30, 2013	Jul. 31, 2013 item	Dec. 31, 2014 item	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2008 item	Jan. 31, 2011	Dec. 31, 2010	Oct. 31, 2013	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2011	Dec. 31, 2006 item	Jul. 31, 2011	Dec. 31, 2009	Dec. 31, 2005	Dec. 31, 2000	Dec. 20, 2011
Schedule of Equity Method Investments [Line Items]
Payment for investment in Unconsolidated Entities			$ 7,887,000	$ 3,520,000	$ 1,000,000
Number of vessels owned or operated													2ish_NumberOfVesselsOwnedOrOperated
Number of vessels immediately employed on long-term bareboat charters			4
Amount contributed towards bank guarantee to finance					500,000
Number of vessels affected by stock issuance to unaffiliated co-investor		6
Percentage of shareholders interest owned		23.68%
Contribution towards minimum value covenant	284,000us-gaap_DebtInstrumentPeriodicPayment
Dividends from Unconsolidated Entities			875,000
Due from Related Parties			1,660,000us-gaap_DueFromRelatedPartiesNoncurrent	1,974,000us-gaap_DueFromRelatedPartiesNoncurrent						1,660,000us-gaap_DueFromRelatedPartiesNoncurrent
Gain (loss) on sale of investments					580,000us-gaap_GainLossOnSaleOfInvestments
Mini-Bulkers [Member]
Schedule of Equity Method Investments [Line Items]
Number of vessels owned or operated			16							16
Oslo Bulk, AS [Member]
Schedule of Equity Method Investments [Line Items]
Unconsolidated entities, cost															6,250,000
Equity investee ownership interest			25.00%	25.00%						25.00%				25.00%	25.00%
Payment for investment in Unconsolidated Entities					750,000
Oslo Bulk, AS [Member] \| Mini-Bulkers [Member]
Schedule of Equity Method Investments [Line Items]
Number of vessels contracted to build						8
Number of vessels owned or operated					4
Oslo Bulk Holding Pte, Ltd (formerly Tony Bulkers) [Member]
Schedule of Equity Method Investments [Line Items]
Equity investee ownership interest								25.00%
Payment for investment in Unconsolidated Entities					250,000		1,600,000	3,900,000
Oslo Bulk Holding Pte, Ltd (formerly Tony Bulkers) [Member] \| Mini-Bulkers [Member]
Schedule of Equity Method Investments [Line Items]
Number of vessels owned or operated								2
Terminales Transgolfo, S.A. DE C.V. [Member]
Schedule of Equity Method Investments [Line Items]
Unconsolidated entities, cost																	228,000
Equity investee ownership interest			49.00%							49.00%							50.00%
Percentage held by unaffiliated owner																50.00%
Percentage of interest acquired by unaffiliated owner																1.00%
Percentage of funded cost			49.00%
Percentage of capital contribution			30.00%
Percentage of cost treated as loan			70.00%
Contribution to working capital of equity investee			0	0						0
Dividends from Unconsolidated Entities			290,000
Due from Related Parties			1,700,000	2,000,000						1,700,000
Saltholmen Shipping Ltd. [Member]
Schedule of Equity Method Investments [Line Items]
Equity investee ownership interest	30.00%		30.00%							30.00%
Payment for investment in Unconsolidated Entities			5,800,000						2,700,000		5,800,000
Dividend received										585,000
Saltholmen Shipping Ltd. [Member] \| Chemical Tankers [Member]
Schedule of Equity Method Investments [Line Items]
Number of vessels contracted to build	2
Number of vessels owned or operated			2							2
Brattholmen Shipping Ltd. [Member]
Schedule of Equity Method Investments [Line Items]
Equity investee ownership interest			30.00%							30.00%
Payment for investment in Unconsolidated Entities			2,100,000
Brattholmen Shipping Ltd. [Member] \| Asphalt Tankers [Member]
Schedule of Equity Method Investments [Line Items]
Number of vessels contracted to build			2
Number of vessels owned or operated			2							2
RTI [Member]
Schedule of Equity Method Investments [Line Items]
Unconsolidated entities, cost													386,000			1,600,000
Equity investee ownership interest																50.00%
Percentage held by unaffiliated owner																		50.00%
Due from Related Parties					1,900,000
Difference between our investment and equity in net assets			973,000							973,000
Proceeds from divestiture of interest												526,000
Promissory notes receivable one												1,800,000
Promissory notes receivable two												137,500
Gain (loss) on sale of investments					$ (967,000)
Interest rate on note receivable			6.00%
Term of note receivable			5 years