Leases - Addtional Information (Detail) ft² in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
Jun. 30, 2017 USD ($) ft²	Sep. 30, 2017 USD ($)
Lessor Lease Description [Line Items]
Total rental payments to be received		$ 167,335
San Francisco, California [Member]
Lessor Lease Description [Line Items]
Area of Office Space Leased \| ft²	287
Lease expiration date	Feb. 28, 2027
Total rental payments to be received	$ 167,300
Building occupancy rate by tenant		43.00%
Incentive Receivable and obligation to pay for tenant improvements		$ 24,900
Accrued deferred lease origination costs	$ 6,500

This element represents costs incurred by the lessor that are (a) costs to originate a lease incurred in transactions with independent third parties that (i) result directly from and are essential to acquire that lease and (ii) would not have been incurred had that leasing transaction not occurred and (b) certain costs directly related to specified activities performed by the lessor for that lease. Those activities are: evaluating the prospective lessee's financial condition; evaluating and recording guarantees, collateral, and other security arrangements; negotiating lease terms; preparing and processing lease documents; and closing the transaction. This element is net of accumulated amortization.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 25
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=77902619&loc=d3e40246-112709

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 35
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=77913719&loc=d3e40879-112712

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 25
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=77902619&loc=d3e40588-112709

+ Details

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

- Definition

Date which lease or group of leases is set to expire, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

Name:	us-gaap_LeaseExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
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_LessorLeaseDescriptionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of lease payments to be received by lessor for operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919396-209981

+ Details

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

- Definition

Carrying amount as of the balance sheet date of improvements having a life longer than one year that were made for the benefit of one or more tenants.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1(f))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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

- Definition

Area of office space leased.

+ References

No definition available.

+ Details

Name:	znga_AreaOfOfficeSpaceLeased
Namespace Prefix:	znga_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Building occupancy rate by tenant.

+ References

No definition available.

+ Details

Name:	znga_BuildingOccupancyRateByTenant
Namespace Prefix:	znga_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_StatementGeographicalAxis=country_CA
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: