Debt instrument, maturity, month and year.

No definition available.

Name:	icon_DebtInstrumentMaturityMonthAndYear
Namespace Prefix:	icon_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- 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

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

- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585

+ Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=icon_SeniorNotesFivePointSevenFivePercentDueAugustTwentyTwentyThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=icon_SeniorSecuredTermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=icon_StarterChinaLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_ConvertibleSubordinatedDebtMember
Namespace Prefix:
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Period Type:

Company's Debt Maturities on Calendar Year Basis (Parenthetical) (Detail) - USD ($) $ in Millions		1 Months Ended	3 Months Ended	9 Months Ended
	Oct. 27, 2017	Oct. 31, 2020	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Mar. 14, 2019	Feb. 22, 2019	Feb. 22, 2018	Oct. 26, 2017	Sep. 30, 2017	Aug. 02, 2017
Debt Instrument [Line Items]
Debt instrument, Maturity Date				2043-01
Principal amount of long term debt	$ 240.7
Repayment of remaining outstanding principal balance	231.0			$ 5.0
5.75% Senior Subordinated Notes Due August 2023
Debt Instrument [Line Items]
Percentage of conversion of convertible notes			5.75%	5.75%		5.75%	5.75%
Senior Secured Term Loan
Debt Instrument [Line Items]
Principal amount of long term debt	$ 57.8		$ 116.4	$ 116.4						$ 300.0		$ 300.0
Repayment of remaining outstanding principal balance			44.7
Senior Secured Term Loan \| Starter China Limited \| Subsequent Event
Debt Instrument [Line Items]
Repayment of remaining outstanding principal balance		$ 11.7
Convertible Notes
Debt Instrument [Line Items]
Percentage of conversion of convertible notes											1.50%
Convertible Notes \| 5.75% Senior Subordinated Notes Due August 2023
Debt Instrument [Line Items]
Principal amount of long term debt			$ 94.4	$ 94.4	$ 94.4				$ 125.0
Percentage of conversion of convertible notes			5.75%	5.75%	5.75%	5.75%		5.75%	5.75%