Goodwill And Other Intangible Assets (Schedule Of Goodwill And Other Intangible Assets) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
Sep. 30, 2013
Goodwill And Other Intangible Assets [Line Items]
Indefinite Life Intangibles, Gross Carrying Amount	$ 2,771
Indefinite Life Intangibles, Net Carrying Amount	2,771
Definite Life Intangibles, Gross Carrying Amount	50,773
Definite Life Intangibles, Accumulated Amortization	(9,660)
Definite Life Intangibles, Reclassified	(11,328)
Definite Life Intangibles, Net Carrying Amount	29,785
Goodwill [Member]
Goodwill And Other Intangible Assets [Line Items]
Indefinite Life Intangibles, Gross Carrying Amount	2,771
Indefinite Life Intangibles, Net Carrying Amount	2,771
Trade Names [Member] \| Frascati Shops, Inc. and Tower, LLC [Member]
Goodwill And Other Intangible Assets [Line Items]
Definite Life Intangibles, Amortization Period	240 months
Definite Life Intangibles, Gross Carrying Amount	65
Definite Life Intangibles, Accumulated Amortization	(4)
Definite Life Intangibles, Net Carrying Amount	61
Trade Names [Member] \| UOS [Member]
Goodwill And Other Intangible Assets [Line Items]
Definite Life Intangibles, Amortization Period	96 months
Definite Life Intangibles, Gross Carrying Amount	1,805
Definite Life Intangibles, Accumulated Amortization	(188)
Definite Life Intangibles, Net Carrying Amount	1,617
Customer Relationships [Member] \| Frascati Shops, Inc. and Tower, LLC [Member]
Goodwill And Other Intangible Assets [Line Items]
Definite Life Intangibles, Amortization Period	240 months
Definite Life Intangibles, Gross Carrying Amount	425
Definite Life Intangibles, Accumulated Amortization	(24)
Definite Life Intangibles, Net Carrying Amount	401
Customer Relationships [Member] \| UOS [Member]
Goodwill And Other Intangible Assets [Line Items]
Definite Life Intangibles, Amortization Period	96 months
Definite Life Intangibles, Gross Carrying Amount	30,928
Definite Life Intangibles, Accumulated Amortization	(3,222)
Definite Life Intangibles, Net Carrying Amount	27,706
Favorable Lease [Member] \| UOS [Member]
Goodwill And Other Intangible Assets [Line Items]
Definite Life Intangibles, Amortization Period	13 months
Definite Life Intangibles, Gross Carrying Amount	1,071
Definite Life Intangibles, Accumulated Amortization	(1,071)
Favorable Lease [Member] \| UOS EBO Acquisition [Member]
Goodwill And Other Intangible Assets [Line Items]
Definite Life Intangibles, Gross Carrying Amount	11,328
Definite Life Intangibles, Reclassified	(11,328)
Favorable Charter [Member]
Goodwill And Other Intangible Assets [Line Items]
Definite Life Intangibles, Amortization Period	24 months
Definite Life Intangibles, Gross Carrying Amount	5,151
Definite Life Intangibles, Accumulated Amortization	$ (5,151)

Finite Lived Intangible Assets Reclassified

No definition available.

Name:	ish_FiniteLivedIntangibleAssetsReclassified
Namespace Prefix:	ish_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	ish_GoodwillAndOtherIntangibleAssetsLineItems
Namespace Prefix:	ish_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying amount of assets that lack physical substance, including goodwill, having a projected indefinite period of benefit.

+ References

No definition available.

+ Details

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

- Definition

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=7658586&loc=d3e16323-109275

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

-Subparagraph a(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

+ Details

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

- Definition

Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

+ Details

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

- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying amount of finite-lived intangible assets, indefinite-lived intangible assets and goodwill. Goodwill is an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Intangible assets are assets, not including financial assets, lacking physical substance.

+ References

No definition available.

+ Details

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