Escrow account period following closing date.

No definition available.

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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Period for amount held in escrow.

+ References

No definition available.

+ Details

Name:	icon_PeriodForAmountHeldInEscrow
Namespace Prefix:	icon_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The designation of funds furnished by a borrower to a lender to assure future payments of the borrower's real estate taxes and insurance obligations with respect to a mortgaged property. Escrow deposits may be made for a variety of other purposes such as earnest money and contingent payments. This element excludes replacement reserves which are an escrow separately provided for within the US GAAP taxonomy.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.10)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- Definition

The difference between the carrying value and the sale price of an investment. A gain would be recognized when the sale price of the investment is greater than the carrying value of the investment. This element refers to the Gain included in earnings and not to the cash proceeds of the sale.

+ References

No definition available.

+ Details

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

- Definition

The cash inflow associated with the sale, maturity and collection of all investments such as debt, security and so forth during the period.

+ 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
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3179-108585

+ Details

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

- 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.

+ Details

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

- Details

Name:	icon_ScheduleOfCostMethodInvestmentsAxis=icon_ComplexMediaIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Acquisitions, Joint Ventures and Investments - Cost Method Investments (Parenthetical) (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	9 Months Ended
	Jul. 31, 2016	Sep. 30, 2016	Sep. 30, 2016
Schedule Of Investments [Line Items]
Gain on sale of investments			$ 10,164
Complex Media
Schedule Of Investments [Line Items]
Cash received in connection with sale of interest	$ 35,300
Additional amount held in escrow	$ 3,700
Period for amount held in escrow	12 months
Period following the closing date for escrow account	18 months
Gain on sale of investments		$ 10,200