Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
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
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

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

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the required periodic payments applied to principal.

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

+ Details

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

- Definition

Amount of unamortized debt discount (premium) and debt issuance costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(2)
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-Section 45
-Paragraph 3
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ 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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ 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
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_OtherAssetsMember
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- Details

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

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_SecuredDebtMember
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Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_DomesticLineOfCreditMember
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Balance Type:
Period Type:

- Details

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Debt - Additional Information (Details) - USD ($)	1 Months Ended	9 Months Ended
Debt - Additional Information (Details) - USD ($)	Oct. 31, 2018	Sep. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Unamortized issuance discount and issuance costs		$ (1,810,000)	$ (2,035,000)
Prepaid Expenses and Other Current Assets
Debt Instrument [Line Items]
Unamortized issuance discount and issuance costs		400,000	400,000
Other Assets
Debt Instrument [Line Items]
Unamortized issuance discount and issuance costs		$ 1,100,000	$ 1,400,000
2018 Credit Facility
Debt Instrument [Line Items]
Debt instrument, due date		Oct. 10, 2025
Line of credit facility, remaining borrowing capacity		$ 70,000,000
2018 Credit Facility \| Term Loan
Debt Instrument [Line Items]
Debt instrument, face amount	$ 220,000,000
Debt instrument, quarterly principal payments	$ 550,000
Debt instrument, due date	Oct. 10, 2025
2018 Credit Facility \| Domestic Line of Credit
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 75,000,000
Debt instrument, due date	Oct. 10, 2023
2018 Credit Facility \| Alternate Base Rate \| Term Loan
Debt Instrument [Line Items]
Applicable margin	2.75%
2018 Credit Facility \| Alternate Base Rate \| Domestic Line of Credit \| Minimum
Debt Instrument [Line Items]
Applicable margin	0.75%
2018 Credit Facility \| Alternate Base Rate \| Domestic Line of Credit \| Maximum
Debt Instrument [Line Items]
Applicable margin	1.50%
2018 Credit Facility \| Eurocurrency Rate \| Term Loan
Debt Instrument [Line Items]
Applicable margin	3.75%
2018 Credit Facility \| Eurocurrency Rate \| Domestic Line of Credit \| Minimum
Debt Instrument [Line Items]
Applicable margin	1.75%
2018 Credit Facility \| Eurocurrency Rate \| Domestic Line of Credit \| Maximum
Debt Instrument [Line Items]
Applicable margin	2.50%