Changes in Carrying Amount of Goodwill by Segment (Parenthetical) (Detail) - Iconix Australia	Sep. 30, 2018	Jul. 31, 2018
Goodwill [Line Items]
Percentage of ownership interest acquired	5.00%	5.00%
International
Goodwill [Line Items]
Percentage of ownership interest acquired	5.00%

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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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