Favorable leasehold interests weighted averaged useful life.

No definition available.

Name:	jill_FavorableLeaseholdInterestsWeightedAverageUsefulLife
Namespace Prefix:	jill_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Unfavorable leasehold interests weighted average useful life.

+ References

No definition available.

+ Details

Name:	jill_UnfavorableLeaseholdInterestsWeightedAverageUsefulLife
Namespace Prefix:	jill_
Data Type:	xbrli:durationItemType
Balance Type:	na
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

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

- Definition

Amount after amortization of leases acquired as part of a real property acquisition at below market lease rate with a finite life.

+ References

No definition available.

+ Details

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

- Definition

This element represents the identifiable intangible asset established upon acquisition based on a favorable difference between the terms of an acquired lease and the current market terms for that lease at the acquisition date.

+ 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 210.5-02.15)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

This element represents a liability associated with the acquisition of an off-market lease when the terms of the lease are unfavorable to the market terms for the lease at the date of acquisition.

+ 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 210.5-02.24)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Details

Name:	us-gaap_BusinessAcquisitionAxis=jill_JJillHoldingsIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Acquisition - Summary of Favorable and Unfavorable Leasehold Interests and Weighted Average Useful Lives (Detail) - USD ($) $ in Thousands	May 08, 2015	Feb. 03, 2018	Jan. 28, 2017
Acquired Finite Lived Intangible Assets [Line Items]
Unfavorable Leasehold Interests, Fair Value at Acquisition		$ (1,809)	$ (2,411)
Holdings [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Favorable Leasehold Interests, Fair Value at Acquisition	$ 161
Unfavorable Leasehold Interests, Fair Value at Acquisition	(3,727)
Net non-market leasehold interests, Fair Value at Acquisation	$ (3,566)
Favorable Leasehold Interests, Weighted Averaged Useful Life	8 years 9 months 18 days
Unfavorable Leasehold Interests, Weighted Averaged Useful Life	6 years 4 months 24 days