Additional Information - Financial Statement Schedule I Condensed Financial Information of Parent Company (Condensed Statements of Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Condensed Financial Statements, Captions [Line Items]
Net income	$ 46,471	$ 14,544	$ 8,491
Other comprehensive income, net of tax:
Foreign currency translation adjustments	2,849	3,278	1,330
Other comprehensive income	2,849	3,278	1,330
Comprehensive income	49,320	17,822	9,821
Add: Comprehensive loss attributable to noncontrolling interest	277	1,027	12
Comprehensive income attributable to Qihoo 360 Technology Co. Ltd	49,597	18,849	9,833
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	46,746	15,603	8,508
Other comprehensive income, net of tax:
Foreign currency translation adjustments	2,851	3,246	1,325
Other comprehensive income	2,851	3,246	1,325
Comprehensive income	49,597	18,849	9,833
Add: Comprehensive loss attributable to noncontrolling interest	0	0	0
Comprehensive income attributable to Qihoo 360 Technology Co. Ltd	$ 49,597	$ 18,849	$ 9,833

Additional Information - Financial Statement Schedule I Condensed Financial Information of Parent Company (Condensed Statements of Comprehensive Income) (Details) (USD $)
In Thousands, unless otherwise specified

12 Months Ended

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2010

Condensed Financial Statements, Captions [Line Items]

Net income

$ 46,471

$ 14,544

$ 8,491

Other comprehensive income, net of tax:

Foreign currency translation adjustments

2,849

3,278

1,330

Other comprehensive income

2,849

3,278

1,330

Comprehensive income

49,320

17,822

9,821

Add: Comprehensive loss attributable to noncontrolling interest

277

1,027

Comprehensive income attributable to Qihoo 360 Technology Co. Ltd

49,597

18,849

9,833

Parent Company [Member]

Condensed Financial Statements, Captions [Line Items]

Net income

46,746

15,603

8,508

Other comprehensive income, net of tax:

Foreign currency translation adjustments

2,851

3,246

1,325

Other comprehensive income

2,851

3,246

1,325

Comprehensive income

49,597

18,849

9,833

Add: Comprehensive loss attributable to noncontrolling interest

Comprehensive income attributable to Qihoo 360 Technology Co. Ltd

$ 49,597

$ 18,849

$ 9,833

- Definition

The change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the reporting entity. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, but excludes any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

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- Definition

The change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to noncontrolling interests. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

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- Definition

The change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the economic entity, including both controlling (parent) and noncontrolling interests. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, including any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

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- Definition

Net of tax and reclassification adjustments of the change in the balance sheet adjustment that results from the process of translating subsidiary financial statements and foreign equity investments into the reporting currency of the reporting entity. Also includes the following: gain (loss) on foreign currency forward exchange contracts; foreign currency transactions designated as hedges of net investment in a foreign entity and intercompany foreign currency transactions that are of a long-term nature, when the entities to the transaction are consolidated, combined, or accounted for by the equity method in the reporting enterprise's financial statements; and gain (loss) on a derivative instrument or nonderivative financial instrument that may give rise to a foreign currency transaction gain (loss) that has been designated and qualified as a hedging instrument for hedging of the foreign currency exposure of a net investment in a foreign operation.

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- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 51

-Paragraph 38

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 55

-Paragraph 4J

-URI http://asc.fasb.org/extlink&oid=18733213&loc=SL4591551-111686

+ Details