Future principal contractual obligations for operating lease commitments undiscounted lease liability excess amount.

No definition available.

Name:	qnst_FuturePrincipalContractualObligationsForOperatingLeaseCommitmentsUndiscountedLeaseLiabilityExcessAmount
Namespace Prefix:	qnst_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

+ References

No definition available.

+ Details

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

- Definition

Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980

+ Details

Name:	us-gaap_LesseeOperatingLeaseRenewalTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
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_OperatingLeasedAssetsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Leases - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2019
Operating Leased Assets [Line Items]
Rent expense	$ 1.0	$ 2.0
Future principal contractual obligations for operating lease commitments undiscounted lease liability excess amount			$ 0.7
Maximum [Member]
Operating Leased Assets [Line Items]
Lessee, operating lease, renewal term			5 years