Fair value method investment ownership percentage.

No definition available.

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Balance Type:	na
Period Type:	instant

- Definition

Allowance for credit losses and revenue reserve is the amount of allowance for credit loss on accounts receivable and revenue reserve.

+ References

No definition available.

+ Details

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

- Definition

Number of clients that accounted for ten percent or more of net accounts receivable.

+ References

No definition available.

+ Details

Name:	qnst_NumberOfClientsThatAccountedForTenPercentOrMoreOfNetAccountsReceivable
Namespace Prefix:	qnst_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of clients that accounted for ten percent or more of net revenue.

+ References

No definition available.

+ Details

Name:	qnst_NumberOfClientsThatAccountedForTenPercentOrMoreOfNetRevenue
Namespace Prefix:	qnst_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of other clients that accounted for ten percent or more of net revenue.

+ References

No definition available.

+ Details

Name:	qnst_NumberOfOtherClientsThatAccountedForTenPercentOrMoreOfNetRevenue
Namespace Prefix:	qnst_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Revenue reserve.

+ References

No definition available.

+ Details

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

- Definition

Summary of significant accounting policies.

+ References

No definition available.

+ Details

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

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9054-108599

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13531-108611

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13537-108611

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CustomerConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_SalesRevenueNetMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_AccountsReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MajorCustomersAxis=qnst_ClientTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MajorCustomersAxis=qnst_ClientThreeMember
Namespace Prefix:
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- Details

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Summary of Significant Accounting Policies - Additional Information (Detail) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Mar. 31, 2021 USD ($) Client	Mar. 31, 2020 Client	Mar. 31, 2021 USD ($) Client	Mar. 31, 2020 Client	Jun. 30, 2020 USD ($) Client
Summary Of Significant Accounting Policies [Line Items]
Revenue reserve \| $	$ 1.1		$ 1.1		$ 0.9
Allowance for credit losses and revenue reserve \| $	$ 1.3		$ 1.3		$ 10.2
Customer Concentration Risk [Member] \| Net revenue [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of clients accounted for more than 10% of net revenue	1	1	1	1
Concentration risk percentage accounted by major clients	26.00%	22.00%	25.00%	19.00%
Number of other clients accounted for more than 10% of net revenue	0	0	0	0
Customer Concentration Risk [Member] \| Accounts Receivable [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of clients accounted for 10% or more than 10% of net accounts receivable			0		0
Customer Concentration Risk [Member] \| Accounts Receivable [Member] \| Client Two [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage accounted by major clients			16.00%		17.00%
Number of clients accounted for 10% or more than 10% of net accounts receivable			1		1
Customer Concentration Risk [Member] \| Accounts Receivable [Member] \| Client Three [Member]
Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage accounted by major clients	11.00%
Number of clients accounted for 10% or more than 10% of net accounts receivable	1
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Fair value method investment ownership percentage	20.00%		20.00%