Qihoo 360 Technology (QIHU) 20-F 25 Apr 14 2013 FY Annual report (foreign) Financial data

Document_and_Entity_Informatio

Document and Entity Information	12 Months Ended
	Dec. 31, 2013
Document Information [Line Items]	'
Document Type	'20-F
Entity Registrant Name	'Qihoo 360 Technology Co Ltd
Entity Well-known Seasoned Issuer	'Yes
Entity Current Reporting Status	'Yes
Entity Filer Category	'Large Accelerated Filer
Entity Central Index Key	'0001508913
Document Fiscal Year Focus	'2013
Document Fiscal Period Focus	'FY
Amendment Flag	'false
Current Fiscal Year End Date	'--12-31
Document Period End Date	31-Dec-13
Common Class A [Member]	'
Document Information [Line Items]	'
Entity Common Stock, Shares Outstanding	134,123,218
Common Class B [Member]	'
Document Information [Line Items]	'
Entity Common Stock, Shares Outstanding	54,767,703

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
ASSETS	'	'
Cash and cash equivalents	$1,013,465	$380,664
Restricted cash	2,368	1,905
Trading securities	253	179
Available-for-sale investment	495	0
Accounts receivable (net of allowance for doubtful accounts of $213 and $145 as of December 31, 2012 and 2013, respectively)	54,598	23,591
Prepaid expenses and other current assets	80,538	26,802
Amounts due from related parties	2,871	0
Deferred tax assets - current	3,129	2,131
Total current assets	1,157,717	435,272
Property and equipment, net	163,864	126,035
Land use rights, net	75,698	73,645
Acquired intangible assets, net	17,248	12,310
Goodwill	29,509	4,628
Long-term investments	84,293	27,559
Other noncurrent assets	39,621	9,335
Deferred tax assets - noncurrent	946	745
Total assets	1,568,896	689,529
LIABILITIES	'	'
Short-term loans (including short-term loans of the consolidated VIEs without recourse to Qihoo 360 Technology Co. Ltd. of $nil and $1,322 as of December 31, 2012 and 2013, respectively)	1,322	0
Accounts payable (including accounts payable of the consolidated VIEs without recourse to Qihoo 360 Technology Co. Ltd. of $7,109 and $22,856 as of December 31, 2012 and 2013, respectively)	25,030	7,109
Accrued expenses and other current liabilities (including accrued expenses and other current liabilities of the consolidated VIEs without recourse to Qihoo 360 Technology Co. Ltd. of $41,488 and $76,736 as of December 31, 2012 and 2013, respectively)	120,418	168,546
Deferred revenue-current (including deferred revenue-current of the consolidated VIEs without recourse to Qihoo 360 Technology Co. Ltd. of $17,520 and $30,717 as of December 31, 2012 and 2013, respectively)	46,632	21,049
Amounts due to related parties (including amount due to related parties of the consolidated VIEs without recourse to Qihoo 360 Technology Co. Ltd. of $148 and $517 as of December 31, 2012 and 2013, respectively)	517	148
Income tax payable (including income tax payable of the consolidated VIEs without recourse to Qihoo 360 Technology Co. Ltd. of $2,710 and $5,546 as of December 31, 2012 and 2013, respectively)	14,679	6,862
Total current liabilities	208,598	203,714
Deferred tax liabilities (including deferred tax liabilities of the consolidated VIEs without recourse to Qihoo 360 Technology Co. Ltd. of $371 and $1,571 as of December 31, 2012 and 2013, respectively)	2,676	790
Deferred revenue-noncurrent (including deferred revenue-noncurrent of the consolidated VIEs without recourse to Qihoo 360 Technology Co. Ltd. of $3,242 and $664 as of December 31, 2012 and 2013, respectively)	3,544	6,762
Long-term debt	600,000	0
Total liabilities	814,818	211,266
Commitments and contingencies (Note 24)	'	'
EQUITY	'	'
Treasury stock	-139	0
Additional paid-in capital	568,675	420,662
Statutory reserves	28,149	16,075
Accumulated other comprehensive income	20,380	9,114
Retained earnings	119,639	32,061
Total Qihoo 360 Technology Co. Ltd. shareholders' equity	736,893	478,096
Noncontrolling interest	17,185	167
TOTAL EQUITY	754,078	478,263
TOTAL LIABILITIES AND EQUITY	1,568,896	689,529
Class A ordinary shares ($0.001 par value; 378,000,000 and 378,000,000 shares authorized as of December 31, 2012 and 2013, respectively; 123,472,524 and 134,123,218 shares issued and outstanding as of December 31, 2012 and 2013, respectively) [Member]	'	'
EQUITY	'	'
Ordinary shares	134	123
Class B ordinary shares ($0.001 par value; 122,000,000 and 122,000,000 shares authorized as of December 31, 2012 and 2013, respectively; 60,684,573 and 54,767,703 shares issued and outstanding as of December 31, 2012 and 2013, respectively) [Member]	'	'
EQUITY	'	'
Ordinary shares	$55	$61

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified
Allowance for doubtful accounts	$145	$213
Short-term loans	1,322	0
Accounts payable	25,030	7,109
Accrued expenses and other current liabilities	120,418	168,546
Deferred revenue-current	46,632	21,049
Amounts due to related parties	517	148
Income tax payable	14,679	6,862
Deferred tax liabilities	2,676	790
Deferred revenue-noncurrent	3,544	6,762
Ordinary shares, par value	$0.00	$0.00
Ordinary shares, shares authorized	500,000,000	500,000,000
Common Class A [Member]	'	'
Ordinary shares, par value	$0.00	$0.00
Ordinary shares, shares authorized	378,000,000	378,000,000
Ordinary shares, shares issued	123,472,524	123,472,524
Ordinary shares, shares outstanding	134,123,218	134,123,218
Common Class B [Member]	'	'
Ordinary shares, par value	$0.00	$0.00
Ordinary shares, shares authorized	122,000,000	122,000,000
Ordinary shares, shares issued	60,684,573	60,684,573
Ordinary shares, shares outstanding	54,767,703	54,767,703
Variable Interest Entity, Primary Beneficiary [Member]	'	'
Short-term loans	1,322	0
Accounts payable	22,856	7,109
Accrued expenses and other current liabilities	76,653	41,488
Deferred revenue-current	30,717	17,520
Amounts due to related parties	517	148
Income tax payable	5,546	2,710
Deferred tax liabilities	1,571	371
Deferred revenue-noncurrent	$664	$3,242

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues:	'	'	'
Internet services	$671,088	$328,882	$166,961
Sale of third party anti-virus software	0	150	890
Total revenues	671,088	329,032	167,851
Cost of revenues:	'	'	'
Internet services	87,838	32,762	18,680
Sale of third party anti-virus software	0	40	238
Total cost of revenues	87,838	32,802	18,918
Subsidy income	2,349	2,570	151
Operating expenses:	'	'	'
Selling and marketing	110,104	58,178	46,836
General and administrative	116,200	34,295	19,054
Product development	255,248	156,269	64,962
Impairment loss on intangible assets	948	1,348	87
Total operating expenses	482,500	250,090	130,939
Income from operations	103,099	48,710	18,145
Interest income	10,398	6,715	2,594
Interest expense	-5,572	0	-53
Other (expense) income	590	1,243	-3
Exchange gain	5,105	49	6,294
Change in unrealized holding (loss) gain of trading securities	75	-52	-220
Realized gain from sales of trading securities	252	0	0
Impairment loss on long-term investments	-5,004	-2,302	-902
Dividend income from a cost method investee	413	0	0
Gain on disposal of long-term investments	15,807	4,766	0
Gain (Loss) on disposal of subsidiaries	-1,144	3,566	0
Income before income tax expense and loss from equity method investments	124,019	62,695	25,855
Income tax expense	-23,423	-11,379	-10,874
Loss from equity method investments	-2,747	-4,845	-437
Net income	97,849	46,471	14,544
Add: Net loss attributable to noncontrolling interest	1,803	275	1,059
Net income attributable to Qihoo 360 Technology Co. Ltd.	99,652	46,746	15,603
Net income attributable to ordinary shareholders of Qihoo 360 Technology Co. Ltd.	99,652	46,746	14,832
Net income per ordinary share-basic (in dollars per share)	$0.55	$0.26	$0.10
Net income per ordinary share-diluted (in dollars per share)	$0.52	$0.25	$0.09
Weighted average shares used in calculating net income per ordinary share-basic (in shares)	180,476,681	176,442,866	149,068,287
Weighted average shares used in calculating net income per ordinary share-diluted (in shares)	193,036,850	183,623,235	172,992,515
Cost of revenues [Member]	'	'	'
Share-based compensation expense included in:	'	'	'
Allocated Share-based Compensation Expense	0	4	16
Selling and marketing [Member]	'	'	'
Share-based compensation expense included in:	'	'	'
Allocated Share-based Compensation Expense	15,389	21,260	31,455
General and administrative [Member]	'	'	'
Share-based compensation expense included in:	'	'	'
Allocated Share-based Compensation Expense	69,101	8,365	4,549
Product development [Member]	'	'	'
Share-based compensation expense included in:	'	'	'
Allocated Share-based Compensation Expense	36,597	20,976	11,969
Series A Preferred Stock [Member]	'	'	'
Operating expenses:	'	'	'
Net income attributable to Qihoo 360 Technology Co. Ltd.	'	'	203
Accretion of convertible participating redeemable preferred shares	'	'	203
Net income per ordinary share-basic (in dollars per share)	'	'	$0.02
Weighted average shares used in calculating net income per ordinary share-basic (in shares)	0	0	8,356,247
Series B Preferred Stock [Member]	'	'	'
Operating expenses:	'	'	'
Net income attributable to Qihoo 360 Technology Co. Ltd.	'	'	313
Accretion of convertible participating redeemable preferred shares	'	'	313
Net income per ordinary share-basic (in dollars per share)	'	'	$0.03
Weighted average shares used in calculating net income per ordinary share-basic (in shares)	0	0	9,755,085
Series C Preferred Stock [Member]	'	'	'
Operating expenses:	'	'	'
Net income attributable to Qihoo 360 Technology Co. Ltd.	'	'	255
Accretion of convertible participating redeemable preferred shares	'	'	$255
Net income per ordinary share-basic (in dollars per share)	'	'	$0.12
Weighted average shares used in calculating net income per ordinary share-basic (in shares)	0	0	2,057,209

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Consolidated Statements of Comprehensive Income [Abstract]	'	'	'
Net income	$97,849	$46,471	$14,544
Other comprehensive income, net of tax:	'	'	'
Foreign currency translation adjustments	11,104	2,849	3,278
Other comprehensive income	11,104	2,849	3,278
Comprehensive income	108,953	49,320	17,822
Add: Comprehensive loss attributable to noncontrolling interest	1,965	277	1,027
Comprehensive income attributable to Qihoo 360 Technology Co. Ltd.	$110,918	$49,597	$18,849

Consolidated_Statements_of_Cha

Consolidated Statements of Changes in Equity (USD $)

Total

Series A Preferred Stock [Member]

Series B Preferred Stock [Member]

Series C Preferred Stock [Member]

Total Qihoo 360 Technology Co. Ltd. shareholders' equity [Member]

Total Qihoo 360 Technology Co. Ltd. shareholders' equity [Member]

Total Qihoo 360 Technology Co. Ltd. shareholders' equity [Member]

Total Qihoo 360 Technology Co. Ltd. shareholders' equity [Member]

Ordinary shares [Member]

Treasury Stock [Member]

Additional paid-in capital [Member]

Statutory reserves [Member]

Accumulated other comprehensive income [Member]

(Accumulated deficit) Retained earnings [Member]

(Accumulated deficit) Retained earnings [Member]

(Accumulated deficit) Retained earnings [Member]

(Accumulated deficit) Retained earnings [Member]

Noncontrolling Interest [Member]

In Thousands, except Share data

Series A Preferred Stock [Member]

Series B Preferred Stock [Member]

Series C Preferred Stock [Member]

Series A Preferred Stock [Member]

Series B Preferred Stock [Member]

Series C Preferred Stock [Member]

Beginning Balance, amount at Dec. 31, 2010

$2,722

'

'

'

$2,215

'

'

'

$72

'

$12,568

$164

$3,017

($13,606)

'

'

'

$507

Beginning Balance, shares (in shares) at Dec. 31, 2010

'

'

'

'

'

'

'

'

71,560,740

'

'

'

'

'

'

'

'

'

Accretion of convertible participating redeemable preferred shares

'

-203

-313

-255

'

-203

-313

-255

'

'

'

'

'

'

-203

-313

-255

'

Issuance of ordinary shares in connection with share-based compensation arrangements, shares (in shares)

'

'

'

'

'

'

'

'

3,059,779

'

'

'

'

'

'

'

'

'

Issuance of ordinary shares in connection with share-based compensation arrangements, amount

3

'

'

'

3

'

'

'

3

'

'

'

'

'

'

'

'

'

Share-based compensation

47,989

'

'

'

47,989

'

'

'

'

'

47,989

'

'

'

'

'

'

'

Issuance of ordinary shares in connection with exercise of share options, shares (in shares)

'

'

'

'

'

'

'

'

31,172

'

'

'

'

'

'

'

'

'

Issuance of ordinary shares in connection with exercise of share options, amount

48

'

'

'

48

'

'

'

'

'

48

'

'

'

'

'

'

'

Issuance of ordinary shares upon initial public offering ("IPO"), shares (in shares)

'

'

'

'

'

'

'

'

26,063,544

'

'

'

'

'

'

'

'

'

Issuance of ordinary shares upon initial public offering ("IPO"), net of offering costs of $2,763, amount

231,549

'

'

'

231,549

'

'

'

26

'

231,523

'

'

'

'

'

'

'

Conversion of participating redeemable preferred shares to ordinary shares, shares (in shares)

'

'

'

'

'

'

'

'

78,314,016

'

'

'

'

'

'

'

'

'

Conversion of participating redeemable preferred shares to ordinary shares, amount

70,971

'

'

'

70,971

'

'

'

78

'

70,893

'

'

'

'

'

'

'

Provision for statutory reserves

'

'

'

'

'

'

'

'

'

'

'

5,503

'

-5,503

'

'

'

'

Noncontrolling interest for establishments of subsidiaries

1,548

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,548

Disposal of noncontrolling interest in subsidiaries

-389

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-389

Net income

14,544

'

'

'

15,603

'

'

'

'

'

'

'

'

15,603

'

'

'

-1,059

Foreign currency translation adjustments

3,278

'

'

'

3,246

'

'

'

'

'

'

'

3,246

'

'

'

'

32

Ending Balance, amount at Dec. 31, 2011

371,492

'

'

'

370,853

'

'

'

179

'

363,021

5,667

6,263

-4,277

'

'

'

639

Ending Balance, shares (in shares) at Dec. 31, 2011

'

'

'

'

'

'

'

'

179,029,251

'

'

'

'

'

'

'

'

'

Issuance of ordinary shares in connection with share-based compensation arrangements, shares (in shares)

'

'

'

'

'

'

'

'

3,512,394

'

'

'

'

'

'

'

'

'

Issuance of ordinary shares in connection with share-based compensation arrangements, amount

3

'

'

'

3

'

'

'

3

'

'

'

'

'

'

'

'

'

Share-based compensation

50,605

'

'

'

50,605

'

'

'

'

'

50,605

'

'

'

'

'

'

'

Issuance of ordinary shares in connection with exercise of share options, shares (in shares)

'

'

'

'

'

'

'

'

1,615,452

'

'

'

'

'

'

'

'

'

Issuance of ordinary shares in connection with exercise of share options, amount

6,965

'

'

'

6,965

'

'

'

2

'

6,963

'

'

'

'

'

'

'

Provision for statutory reserves

'

'

'

'

'

'

'

'

'

'

'

10,408

'

-10,408

'

'

'

'

Noncontrolling interest for establishments of subsidiaries

422

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

422

Disposal of noncontrolling interest in subsidiaries

-544

'

'

'

73

'

'

'

'

'

73

'

'

'

'

'

'

-617

Net income

46,471

'

'

'

46,746

'

'

'

'

'

'

'

'

46,746

'

'

'

-275

Foreign currency translation adjustments

2,849

'

'

'

2,851

'

'

'

'

'

'

'

2,851

'

'

'

'

-2

Ending Balance, amount at Dec. 31, 2012

478,263

'

'

'

478,096

'

'

'

184

'

420,662

16,075

9,114

32,061

'

'

'

167

Ending Balance, shares (in shares) at Dec. 31, 2012

'

'

'

'

'

'

'

'

184,157,097

'

'

'

'

'

'

'

'

'

Issuance of ordinary shares in connection with share-based compensation arrangements, shares (in shares)

'

'

'

'

'

'

'

'

561,517

'

'

'

'

'

'

'

'

'

Issuance of ordinary shares in connection with share-based compensation arrangements, amount

1

'

'

'

1

'

'

'

1

'

'

'

'

'

'

'

'

'

Share repurchase, shares (in shares)

'

'

'

'

'

'

'

'

-14,544

'

'

'

'

'

'

'

'

'

Share repurchase, amount

-139

'

'

'

-139

'

'

'

'

-139

'

'

'

'

'

'

'

'

Share-based compensation

121,087

'

'

'

121,087

'

'

'

'

'

121,087

'

'

'

'

'

'

'

Issuance of ordinary shares in connection with exercise of share options, shares (in shares)

3,982,385

'

'

'

'

'

'

'

3,982,385

'

'

'

'

'

'

'

'

'

Issuance of ordinary shares in connection with exercise of share options, amount

19,071

'

'

'

19,071

'

'

'

4

'

19,067

'

'

'

'

'

'

'

Issuance of ordinary shares in connection with business acquisitions, shares (in shares)

'

'

'

'

'

'

'

'

204,466

'

'

'

'

'

'

'

'

'

Issuance of ordinary shares in connection with business acquisitions, amount

7,864

'

'

'

7,864

'

'

'

'

'

7,864

'

'

'

'

'

'

'

Provision for statutory reserves

'

'

'

'

'

'

'

'

'

'

'

12,074

'

-12,074

'

'

'

'

Addition of noncontrolling interest in connection with business acquisitions

18,868

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

18,868

Capital injection of non-controlling interest holders to a subsidiary

654

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

654

Disposal of noncontrolling interest in subsidiaries

-544

'

'

'

-5

'

'

'

'

'

-5

'

'

'

'

'

'

-539

Net income

97,849

'

'

'

99,652

'

'

'

'

'

'

'

'

99,652

'

'

'

-1,803

Foreign currency translation adjustments

11,104

'

'

'

11,266

'

'

'

'

'

'

'

11,266

'

'

'

'

-162

Ending Balance, amount at Dec. 31, 2013

$754,078

'

'

'

$736,893

'

'

'

$189

($139)

$568,675

$28,149

$20,380

$119,639

'

'

'

$17,185

Ending Balance, shares (in shares) at Dec. 31, 2013

'

'

'

'

'

'

'

'

188,890,921

'

'

'

'

'

'

'

'

'

Consolidated_Statements_of_Cha1

Consolidated Statements of Changes in Equity (Parenthetical) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2011
Consolidated Statements of Changes in Equity [Abstract]	'
Offering Costs	$2,763

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:	'	'	'
Net income	$97,849	$46,471	$14,544
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'
Share-based compensation	121,087	50,605	47,989
Depreciation and amortization	42,629	16,457	4,227
Amortization of land use rights	1,714	140	0
(Gain) loss on disposal of property and equipment	213	-838	0
Loss from impairment of intangible assets	948	1,348	87
Provision of allowance for doubtful accounts	157	454	51
Unrealized holding loss (gain) on trading securities	-75	52	220
Realized gain from sales of trading securities	-252	0	0
Loss on equity method investments	2,747	4,845	437
Dividend income from a cost method investee	-413	0	0
Loss from impairment of long-term investments	5,004	2,302	902
(Gain) loss on disposal of subsidiaries	1,144	-3,566	0
Gain on disposal of long-term investments	-15,807	-4,766	0
Changes in operating assets and liabilities:	'	'	'
Accounts receivable	-30,789	-6,765	-8,066
Prepaid expenses and other current assets	-40,271	-8,404	-8,684
Amount due from related parties	-1,645	0	0
Payment for land use rights	-72,888	-14,102	0
Deferred taxes	837	-1,204	-315
Other noncurrent assets	-3,010	392	-4,077
Accounts payable	18,796	1,164	4,603
Accrued expenses and other current liabilities	53,605	23,274	11,554
Deferred revenue	20,466	10,354	10,744
Amount due to related parties	366	83	964
Income tax payable	7,814	-508	7,123
Net cash provided by operating activities	210,226	117,788	82,303
Cash flows from investing activities:	'	'	'
Restricted cash	-431	-1,902	0
Purchase of property and equipment	-118,334	-68,796	-16,320
Proceeds from disposal of property and equipment	1	2,126	0
Purchase of intangible assets	-3,068	-5,073	-1,457
Purchase of other assets	0	-459	-1,571
Purchase of trading securities and payments for available-for-sale investments	-997	0	-451
Proceeds from sale of trading securities	762	0	0
Capital contribution for cost method investments	-35,617	-8,023	-7,599
Capital contribution for equity method investments	-45,350	-16,218	-6,926
Cash Collected from Disposal of Long-term Investments and Subsidiaries	18,880	13,847	0
Dividends received from a cost method investee	413	313	0
Net cash (paid for) acquired from business acquisition	-9,827	258	-487
Deconsolidation of a subsidiary	-3,306	0	0
Net cash used in investing activities	-196,874	-83,927	-34,811
Cash flows from financing activities:	'	'	'
Proceeds from issuance of Convertible Senior Notes (net of issuance cost of $12,150)	587,850	0	0
Proceeds from exercise of share options	23,678	2,089	20
Proceeds from issuance of ordinary shares upon IPO	0	0	234,312
Payment of IPO costs	0	0	-2,611
Capital contribution from noncontrolling interest shareholders	656	36	1,559
Proceeds from short-term loans	1,314	0	0
Payment for share repurchase	0	-139	0
Net cash provided by financing activities	613,498	1,986	233,280
Effect of exchange rate on cash and cash equivalents	5,951	1,086	2,454
Net increase in cash and cash equivalents	632,801	36,933	283,226
Cash and cash equivalents at beginning of year	380,664	343,731	60,505
Cash and cash equivalents at end of year	1,013,465	380,664	343,731
Supplemental disclosure of cash flow information:	'	'	'
Income tax paid	13,961	12,578	3,699
Supplemental schedule of non-cash activities:	'	'	'
Conversion of participating redeemable preferred shares to ordinary shares	'	'	70,971
Payable for purchasing land use rights, plant, property and equipment and intangible assets	20,861	125,760	915
Consideration payable in connection with business acquisition	358	0	0
Accrued and deferred IPO costs	0	0	108
Nonmonetary transaction (Note 9(ii))	0	0	2,100
Issuance of ordinary shares for business acquisition	$7,864	'	'

Consolidated_Statements_of_Cas1

Consolidated Statements of Cash Flows (Parenthetical) (Convertible Senior Notes [Member], USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013
Convertible Senior Notes [Member]	'
Debt issuance cost	$12,150

Organization_and_Principal_Act

Organization and Principal Activities	12 Months Ended
	Dec. 31, 2013
Organization and Principal Activities [Abstract]	'
Organization and Principal Activities	'
		1	ORGANIZATION AND PRINCIPAL ACTIVITIES
	Qihoo 360 Technology Co. Ltd. (the "Company" or "Qihoo 360", formerly known as Qihoo Technology Company Limited), incorporated in the Cayman Islands in June 2005, with its consolidated subsidiaries, variable interest entities ("VIEs") and VIEs' subsidiaries (collectively referred to the "Group") is primarily involved in the operations of internet services in the People's Republic of China (the "PRC"). Prior to April 2012, the Group also involved in sales of third party anti-virus software in the PRC and such operation was diminished after the expiry of the agreement with the third-party developer in April 2012.
	As of December 31, 2013, the Company has wholly-owned and majority-owned subsidiaries incorporated in countries and jurisdictions including PRC, Hong Kong, U.S.A, Singapore and Japan. The Company's major subsidiaries are as follows:
		•	Qiji International Development Limited ("Qiji International")
		•	Qifei International Development Co. Limited ("Qifei International")
		•	360 International Development Co. Limited ("360 International")
		•	Qizhi Software (Beijing) Co., Ltd. ("Qizhi Software")
		•	Tianjin Qisi Technology Co., Ltd. ("Tianjin Qisi")
	As of December 31, 2013, the Company also effectively controls VIEs under contractual arrangements. The major VIEs are as follows:
		•	Beijing Qihu Technology Co., Ltd. ("Beijing Qihu")
		•	Beijing Star World Technology Co., Ltd. ("Beijing Star World")
	History of the Group and corporate reorganization
	Qizhi Software, a wholly foreign owned subsidiary in PRC, entered into a series of contractual arrangements with Beijing Qihu, Beijing Star World and other VIEs (collectively the "VIEs") from 2006 to 2013. (See below for a description of the VIE arrangements under which the Company, or its subsidiaries, is the primary beneficiary of its consolidated VIEs and their subsidiaries).
	/
	The VIE arrangements
	PRC regulations currently limit direct foreign ownership of business entities providing internet services in the PRC where certain licenses are required for the provision of such services. To comply with these PRC regulations, the Company conducts substantially the majority of its business through the VIEs and their subsidiaries. To provide the Company the expected residual returns of the VIEs and their subsidiaries, Qizhi Software has entered into the following contractual arrangements with the VIEs and their shareholders that enable the Company to (1) have power to direct the activities that most significantly affect the economic performance of the VIEs, and (2) receive the economic benefits of the VIEs that could be significant to the VIEs. Accordingly, the Company is considered the primary beneficiary of the VIEs and has consolidated the VIEs' financial results of operations, assets and liabilities in the Company's consolidated financial statements. In making the conclusion that the Company is the primary beneficiary of the VIEs, the Company believes the Company's rights under the terms of the equity disposition agreements provide it with a substantive kick out right. More specifically, the Company believes the terms of the equity disposition agreements are valid, binding and enforceable under PRC laws and regulations currently in effect. A simple majority vote of the Company's board of directors is required to pass a resolution to exercise the Company's rights under the exclusive option agreement, for which the consent from the shareholders of the VIEs is not required. The Company's rights under the equity disposition agreements give the Company the power to control the shareholders of the VIEs and thus the power to direct the activities that most significantly impact the VIEs' economic performance. In addition, the Company's rights under the powers of attorney also reinforce the Company's abilities to direct the activities that most significantly impact the VIEs' economic performance. The Company also believes that this ability to exercise control ensures that the VIEs will continue to execute and renew service agreements and pay service fees to the Company. By charging service fees in whatever amounts the Company deems fit, and by ensuring that service agreements are executed and renewed indefinitely, the Company has the rights to receive substantially all of the economic benefits from the VIEs.
	The series of contractual arrangements are summarized as follows:
	Business Operation Agreements
	Under the Business Operation Agreements, the registered shareholders of VIEs and the VIEs may not enter into any transaction that could materially affect the assets, liabilities, interests or operations of the VIEs, without Qizhi Software's prior written consent. In addition, directors, general managers, financial controllers or other senior managers of VIEs must be Qizhi Software's nominees appointed by the registered shareholders of the VIEs. Each business operation agreement has a term of ten years and is renewable at Qizhi Software's sole discretion.
	Technology Consulting and Services Agreements
	Under the Technology Consulting and Services Agreements, Qizhi Software agreed to provide the VIEs with technology support and consulting services. VIEs agreed to pay certain percentage of its revenue as service fees to Qizhi Software. The service fees are subject to adjustment by Qizhi Software. The agreements have a term of three to ten years unless terminated upon both parties' agreement. The agreement may be renewed upon Qizhi Software's approval and the renewed term will be based on agreement of both parties.
	Equity Disposition Agreements
	The agreements granted Qizhi Software or its designated person exclusive options to purchase, when and to the extent permitted under PRC law, any part or all of the equity interests in the VIEs. The exercise price for the options to purchase all of the equity interests is the minimum amount of consideration permissible under the then applicable PRC law. The agreements have an initial term of ten years and are renewable at Qizhi Software's sole discretion. Under the equity disposition agreements, the registered shareholders of the VIEs may sell the pledged shares to the Company at a nominal price to pay off the loans. The Company absorbs losses of the VIEs, and is exposed to the risk of losses from the operation of the VIEs.
	Loan Agreements
	Under Loan Agreements between the Company and the registered shareholders of VIEs, the Company extended loans to the registered shareholders of VIEs for contributing registered capital to the VIEs in order to hold 100% of the equity interest in the VIEs. Each loan agreement has a term of ten years and is renewable upon both parties' agreement.
	Equity Pledge Agreements
	Under Qizhi Software's Equity Pledge Agreements with the VIEs and their respective registered shareholders, the registered shareholders of the VIEs pledged all of their respective equity interests in favor of Qizhi Software to secure VIEs' obligations under the Equity Disposition Agreements and Business Operation Agreements described above. If any of the VIEs breaches any of their respective contractual obligations under these agreements seriously, Qizhi Software, as pledgee, will be entitled to dispose the pledged equity interests. The registered shareholders of VIEs agreed not to dispose of, or otherwise create any new encumbrance on their respective equity interests in the VIEs, and not to approve the VIEs to merge with other entities or reorganize in any other forms, without Qizhi Software's prior written consent. Unless terminated at Qizhi Software's sole discretion, each equity pledge agreement has a term of ten years and is renewable at Qizhi Software's sole discretion, similar to the term of Equity Disposition Agreements and Business Operation Agreements.
	Power of Attorney
	Each registered shareholder of VIEs, has executed a power of attorney appointing Qizhi Software to be his or her attorneys, and irrevocably authorizing Qizhi Software to vote on his or her behalf on all of the matters concerning the VIEs, that may require shareholders' approval. The term of power of attorney is ten years. The Power of Attorney can be renewed at Qizhi Software's sole discretion.
	Spousal Consent
	Under the Spousal Consent letters, the spouse of each married registered shareholder of VIEs has signed a spousal consent letter, whereby the spouse agrees that (i) the equity interests of the VIEs owned by such shareholder will be disposed of only in accordance with the applicable Equity Disposition Agreement, Equity Pledge Agreement, Loan Agreement and other related agreements executed by the shareholder, (ii) such equity interests do not constitute communal property with such shareholder and (iii) the spouse irrevocably and unconditionally waives all rights and benefits with respect to such equity interests, including the right to sue in any court and under all applicable laws.
	As a result of the contractual arrangements described above, Qizhi Software has the power to direct the activities of the VIEs that most significantly affect the entity's economic performance, bears the economic risks and receives the economic benefits of the VIEs, and is the primary beneficiary of the VIEs. Therefore, the Company has consolidated the financial results of the VIEs and their subsidiaries in its consolidated financial statements since the later of the date of acquisition and incorporation.
	Risks in relation to the VIE structure
	The Company believes that Qizhi Software's contractual arrangements with the VIEs are in compliance with PRC law and are legally enforceable. However, uncertainties in the PRC legal system could limit the Company's ability to enforce the contractual arrangements. If the legal structure and contractual arrangements were found to be in violation of PRC laws and regulations, the PRC government could:
		•	revoke the Group's business and operating licenses
		•	require the Group to discontinue or restrict the Group's operations
		•	restrict the Group's right to collect revenues,
		•	block the Group's websites,
		•	require the Group to restructure the Group's operations,
		•	impose additional conditions or requirements with which the Group may not be able to comply
		•	impose restrictions on the Group's business operations or on the Group's customers or take other regulatory or enforcement actions against the Group that could be harmful to the Group's business.
	The Company's ability to conduct its business may be negatively affected if the PRC government were to carry out of any of the aforementioned actions. As a result, the Company may not be able to consolidate the VIEs in its consolidated financial statements as it may lose the ability to exert effective control over the VIEs and their shareholders, and it may lose the ability to receive economic benefits from the VIEs.
	The shareholders of the VIEs are directors or officers of the Company. Most of them are also shareholders of the Company. Therefore they have no current interest in seeking to act contrary to the contractual arrangements. The interests of the VIEs' shareholders may differ from the interests of the Company as a whole. The Company cannot assure that when conflicts of interest arise, the shareholders will act in the best interests of the Company or that conflicts of interests will be resolved in the Company's favor. Currently, the Company does not have existing arrangements to address potential conflicts of interest the shareholders of the VIEs may encounter in their capacity as the beneficial owners and directors or officers of the VIEs, on the one hand, and as beneficial owners and directors or officers of the Company, on the other hand. The Company believes the shareholders of the VIEs will not act contrary to any of the contractual arrangements and the equity disposition agreements provide the Company with a mechanism to remove the shareholders as the beneficial shareholders of the VIEs should they act to the detriment of the Company. The Company relies on the VIEs' shareholders, as directors and officers of the Company, to fulfill their fiduciary duties and abide by laws of the PRC and Cayman Islands and act in the best interest of the Company. If the Company cannot resolve any conflicts of interest or disputes between the Company and the VIEs' shareholders, the Company would have to rely on legal proceedings, which could result in disruption of its business, and there is substantial uncertainty as to the outcome of any such legal proceedings.
	To further protect the investors' interest from any risk that the shareholders of the VIEs may act contrary to the contractual arrangements, the Company, through Qizhi Software, entered into irrevocable powers of attorney with the registered shareholders of the VIEs. Through these powers of attorney, the shareholders of the VIEs entrusted Qizhi Software as its proxy to exercise its rights as the shareholders of the VIEs with respect to an aggregate of 100% of the equity interests in the VIEs. The term of power of attorney is ten years. The power of attorney can be renewed at Qizhi Software's sole discretion.
	The following consolidated financial statement balances and amounts of the Group's VIEs and their subsidiaries were included in the accompanying consolidated financial statements after the elimination of intercompany balances and transactions between the offshore companies, WFOEs, VIEs and VIEs’ subsidiaries in the Group:
			December 31,
			2012			2013
	Cash and cash equivalents		$	58,108		$	116,575
	Restricted cash			1,605			2,068
	Account receivable and other current assets			34,976			61,177
	Total current assets			94,689			179,820
	Property and equipment, net			57,275			91,861
	Acquired intangible assets, net			5,113			9,681
	Other noncurrent assets			26,814			37,778
	Total noncurrent assets			89,202			139,320
	Total assets			183,891			319,140
	Deferred revenue, current			17,520			30,717
	Account payable and other current liabilities			51,455			106,894
	Total current liabilities			68,975			137,611
	Total noncurrent liabilities			3,613			2,235
	Total liabilities		$	72,588		$	139,846
			Year ended December 31,
			2011			2012			2013
Revenues		$	160,613		$	303,200		$	527,646
Net income		$	78,494		$	150,408		$	263,514
		Year ended December 31,
		2011			2012			2013
Net cash provided by operating activities		$	56,621		$	75,983		$	129,175
Net cash used in investing activities			(32,367	)		(50,951	)		(72,678	)
Net cash provided by financing activities			1,545			36			1,970
		$	25,799		$	25,068		$	58,467
As of December 31, 2011, 2012 and 2013, the balance of the amount payable by the VIEs and their subsidiaries to WOFEs related to the service fees was nil, US$2.3 million and US$0.1 million, respectively and was eliminated upon consolidation.
The Group conducted substantially all of its Internet business through VIEs and the VIEs contributed an aggregate of 95.7%, 92.1% and 78.6% of the consolidated revenues for the years ended December 31, 2011, 2012 and 2013, respectively. The Group's operations not conducted through contractual arrangements with the VIEs primarily consist of its advertisement agency service and technology support service. As of December 31, 2012 and 2013, the VIEs accounted for an aggregate of 26.7% and 20.3%, respectively, of the consolidated total assets, and 34.4% and 17.2%, respectively, of the consolidated total liabilities. The assets not associated with the VIEs primarily consist of cash and cash equivalent, account receivables, property and equipment, and land use rights. The recognized and unrecognized revenue-producing assets that are held by the VIEs are primarily the following:
	•	Property and equipment
	•	Acquired intangible assets, such as domain names, licenses, trademarks, source code and non-compete agreements
	•	Other noncurrent assets, which mainly include long term royalty fees and license fees, long term rental deposits
	•	Self-developed intangible assets such as patents which are un-recognized at consolidated balance sheets
As of December 31, 2013, approximately 33% of the Group's employees that provide the Group's services are hired by the VIEs and their subsidiaries. The nominee shareholders of the VIEs and their subsidiaries have in the past received loans from the Company or WFOEs for capital contribution. There are no consolidated VIEs' assets that are collateral for the VIEs' obligations and can only be used to settle the VIEs' obligations. There are no creditors (or beneficial interest holders) of the VIEs that have recourse to the general credit of the Company or any of its consolidated subsidiaries. There are no terms in any arrangements, considering both explicit arrangements and implicit variable interests that require the Company or its subsidiaries to provide financial support to the VIEs. However, if the VIEs ever need financial support, the Company or its subsidiaries may, at its option and subject to statutory limits and restrictions, provide financial support to its VIEs through loans to the shareholder of the VIEs or entrustment loans to the VIEs.
Relevant PRC laws and regulations restrict the VIEs from transferring a portion of their net assets, equivalent to the balance of its statutory reserve and its share capital, to the Company in the form of loans and advances or cash dividends. Please refer to Note 28 for disclosure of restricted net assets.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
Summary of Significant Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
		2	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	Basis of presentation
	The consolidated financial statements of the Group have been prepared in accordance with accounting principles generally accepted in the United States of America ("US GAAP").
	Basis of consolidation
	The consolidated financial statements of the Group include the financial statements of the Company, its wholly owned subsidiaries and VIEs and their subsidiaries. All inter-company transactions and balances have been eliminated upon consolidation.
	Use of estimates
	The preparation of the consolidated financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and the reported amounts of revenues and expenses in the consolidated financial statements and accompanying notes. Significant accounting estimates reflected in the Group's consolidated financial statements include allowance for doubtful accounts, valuations of acquired intangible assets, share-based compensation, valuation allowances for deferred tax assets, impairment of long-term investments, impairment of long-lived assets, useful lives of definite-lived intangible assets and other long-lived assets as well as goodwill impairment assessment.
	Fair value measurements
	Authoritative literature provides a fair value hierarchy, which prioritizes the inputs to valuation techniques used to measure fair value into three broad levels. The level in the hierarchy within which the fair value measurement in its entirety falls is based upon the lowest level of input that is significant to the fair value measurement as follows:
		•	Level 1-inputs are based upon unadjusted quoted prices for identical instruments traded in active markets.
		•	Level 2-inputs are based upon quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation techniques for which all significant assumptions are observable in the market or can be corroborated by observable market data for substantially the full term of the assets or liabilities.
		•	Level 3-inputs are generally unobservable and typically reflect management's estimates of assumptions that market participants would use in pricing the asset or liability. The fair values are therefore determined using model-based techniques that include option pricing models, discounted cash flow models, and similar techniques.
	The Group measures certain assets, including the long-term investments and intangible assets, at fair value on a nonrecurring basis when they are deemed to be impaired. The fair values of these investments and intangible assets are determined based on valuation techniques using the best information available, and may include management judgments, future performance projections, etc. An impairment charge to the long-term investments is recorded when the cost of the investment exceeds its fair value and this condition is determined to be other-than-temporary, and impairment charge to the intangible assets is recorded when their carrying amounts may not be recoverable.
	Cash and cash equivalents
	Cash and cash equivalents consist of cash on hand and term deposits, which are unrestricted as to withdrawal or use.
	Trading securities
	The securities that are bought and held principally for the purpose of selling them in the near term are classified as trading securities. Unrealized holding gains and losses for trading securities are included in the consolidated statements of operations.
	Accounts receivable and allowance for doubtful accounts
	Accounts receivable represents those receivables derived in the ordinary course of business. Allowance for doubtful accounts reflect the Group's best estimate of probable losses inherent in the accounts receivable balances. The Group regularly review allowances by considering factors such as historical experience, credit quality, the age of the accounts receivable balances and current economic conditions that may affect a customer's ability to pay.
	Fair value of financial instruments
	Financial instruments primarily consist of cash and cash equivalents, restricted cash, trading securities, available-for-sale investment, accounts receivable, amounts due from related parties and accounts payable, amounts due to related parties, short-term loans and long-term debt. The carrying amounts of these financial instruments, except for long-term debt, approximate their fair values because of their generally short maturities.
	Property and equipment, net
	Property and equipment is carried at cost less accumulated depreciation and amortization. Depreciation and amortization are calculated on a straightline basis over the following estimated useful lives:
	Computer equipment and application software		3 years
	Building		44 - 60 years
	Office building related facility and machines		10 - 15 years
	Furniture and vehicles		3 - 5 years
	Leasehold improvements		lesser of the lease term or the estimated
			useful life of the assets
	Property and equipment that are purchased or constructed which require a period of time before the assets are ready for their intended use are accounted for as construction-in-progress. Construction-in-progress is recorded at acquisition cost, including installation costs. Construction-in-progress is transferred to specific property and equipment accounts and commences depreciation when these assets are ready for their intended use.
	Land use rights, net
	All land in the PRC is owned by the PRC government, which, according to the relevant PRC law, may grant the right to use the land for a specified period of time. Payment for acquiring land use rights are stated at cost less accumulated amortization and any recognized impairment loss. Amortization is provided on a straight-line basis over the term of the land use rights.
	Acquired intangible assets, net
	Acquired intangible assets are estimated by management based on the fair value of assets acquired. Identifiable intangible assets are carried at cost less accumulated amortization. Amortization of definite-lived intangible assets is computed using the straight-line method over the following estimated useful lives, which are as follows:
	Domain names	3 - 10 years
	Source code	5 - 8 years
	Technology	2 - 10 years
	Non-compete agreement	1 - 5 years
	Trade mark	3 years
	Operating license	8 years
	Customer relationship	3 years
	User base	1 year
	Impairment of long-lived assets
	The Group evaluates the recoverability of long-lived assets, including identifiable intangible assets with determinable useful lives, whenever events or changes in circumstances indicate that a long-lived asset's carrying amount may not be recoverable. The Group measures the carrying amount of long-lived asset against the estimated undiscounted future cash flows associated with it. Impairment exists when the sum of the expected future net cash flows is less than the carrying value of the asset being evaluated. Impairment loss is calculated as the amount by which the carrying value of the asset exceeds its fair value. Fair value is estimated based on various valuation techniques, including the discounted value of estimated future cash flows. The evaluation of asset impairment requires the Group to make assumptions about future cash flows over the life of the asset being evaluated. These assumptions require significant judgment and actual results may differ from assumed and estimated amounts. During the years ended December 31, 2011, 2012 and 2013, the Group recognized $87, $1,151 and $107, respectively, of impairment losses on identifiable intangible assets with determinable useful lives. The related intangible assets are impaired in full when impairment indicators are noted.
	Impairment of indefinite-lived intangible assets
	An intangible asset that is not subject to amortization is tested for impairment at least annually or more frequently if events or changes in circumstances indicate that the asset might be impaired. Such impairment test is to compare the fair values of assets with their carrying amounts and an impairment loss is recognized if and when the carrying amounts exceed the fair values. The estimates of fair values of intangible assets not subject to amortization are determined using various discounted cash flow valuation methodologies. Significant assumptions are inherent in this process, including estimates of discount rates or market price. Discount rate assumptions are based on an assessment of the risk inherent in the respective intangible assets. Market prices are based on potential purchase quote from third party, if any. During the years ended December 31, 2011, 2012 and 2013, the Group recognized nil, $197 and $841, respectively, of impairment losses on its indefinite-lived intangible assets.
	Goodwill
	Goodwill represents the excess of the purchase price over the fair value of identifiable net assets acquired in business combinations. Goodwill is not amortized but is tested for impairment annually or more frequently if events or changes in circumstances indicate that it might be impaired.
	Goodwill is tested for impairment at the reporting unit level on an annual basis (December 31 for the Group) and between annual tests if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying value. These events or circumstances could include a significant change in the stock prices, business climate, legal factors, operating performance indicators, competition, or sale or disposition of a significant portion of a reporting unit.
	In the evaluation of the goodwill for impairment, the Group may first assess qualitative factors to determine whether it is "more likely than not" that the fair value of a reporting unit is less than its carrying amount as a basis for determining whether it is necessary to perform the two-step goodwill impairment test. If it is more likely than not that the fair value of a reporting unit is less than its carrying amount, goodwill is then tested following a two-step process.
	The first step compares the fair value of each reporting unit to its carrying amount, including goodwill. If the fair value of each reporting unit exceeds its carrying amount, goodwill is not considered to be impaired and the second step will not be required. If the carrying amount of a reporting unit exceeds its fair value, the second step compares the implied fair value of goodwill to the carrying value of a reporting unit's goodwill. The implied fair value of goodwill is determined in a manner similar to accounting for a business combination with the allocation of the assessed fair value determined in the first step to the assets and liabilities of the reporting unit. The excess of the fair value of the reporting unit over the amounts assigned to the assets and liabilities is the implied fair value of goodwill. An impairment loss is recognized for any excess in the carrying value of goodwill over the implied fair value of goodwill.
	Application of the goodwill impairment test requires judgment, including the identification of reporting units, assignment of assets and liabilities to reporting units, assignment of goodwill to reporting units, and determination of the fair value of each reporting unit. The estimation of fair value of each reporting unit using a discounted cash flow methodology also requires significant judgments, including estimation of future cash flows, which is dependent on internal forecasts, estimation of the long-term rate of growth for the Group's business, estimation of the useful life over which cash flows will occur, and determination of the Group's weighted average cost of capital. The estimates used to calculate the fair value of a reporting unit change from year to year based on operating results and market conditions. Changes in these estimates and assumptions could materially affect the determination of fair value and goodwill impairment for the reporting unit.
	In 2013, the Group assessed the qualitative factors to determine it is not " more likely than not" that the fair value of each reporting unit is less than its respective carrying amount. The Group did not incur any impairment loss on goodwill for the years ended December 31, 2011, 2012 and 2013.
	Cost method investments
	For investee companies over which the Group does not have significant influence and a controlling interest, the Group carries the investment at cost and recognize as income for any dividend received from distribution of the investee's earnings.
	The Group reviews its cost method investments for impairment whenever an event or circumstance indicates that an other-than-temporary impairment has occurred. The Group considers available quantitative and qualitative evidence in evaluating potential impairment of its cost method investments. An impairment charge is recorded if the cost of an investment exceeds its fair value and such excess is determined to be other-than-temporary. The Group estimated the fair value of these investee companies based on discounted cash flow approach. Factors the Group considers in making such a determination include general market conditions, the duration and the extent to which the fair value of an investment is less than its cost, and the Group's intent and ability to hold such investment. As a result of the assessment process for its cost method investments, the Group recognized impairment charge of $666, $761 and $867 in 2011, 2012 and 2013, respectively.
	Equity method investments
	Investee companies over which the Group has the ability to exercise significant influence, but does not have a controlling interest, are accounted for using the equity method. Significant influence is generally considered to exist when the Group has an ownership interest in the voting stock of the investee between 20% and 50%, and other factors, such as representation on the investee's board of directors, voting rights and the impact of commercial arrangements, are considered in determining whether the equity method of accounting is appropriate.
	An impairment charge is recorded if the carrying amount of the investment exceeds its fair value and this condition is determined to be other-than-temporary. The Group estimated the fair value of these investee companies based on discounted cash flow approach which requires significant judgments, including the estimation of future cash flows, which is dependent on internal forecasts, the estimation of long term growth rate of a company's business, the estimation of the useful life over which cash flows will occur, and the determination of the weighted average cost of capital. Certain of the equity method investments experience a deteriorating financial position and performance and the Group does not expect them to generate any positive future cash flows. Accordingly, the Group accrued an impairment charge of $236, $1,541 and $4,137 in 2011, 2012 and 2013, respectively, on these equity method investments based on their fair value which would be minimal.
	Revenue recognition
	The Group generates its revenue through internet services and sales of third party anti-virus software. The Group recognizes revenue when persuasive evidence of an arrangement exists, delivery has occurred, the sales price is fixed or determinable, and collectability is reasonably assured.
	Internet services revenue
	Internet services revenue includes online advertising, internet value-added services and other services.
	-1	Online advertising
The Group offer marketing opportunities to customers by providing online advertising services, such as sponsored links (advertising links), on the Group's platform products, such as 360 Personal Start-up Page, 360 Search and 360 Mobile Assistant. The Group generally offer these advertising links to customers on a pay-for-effectiveness basis, which primarily includes a cost over time period model and cost for performance model. The Group charge fees to customers directly or indirectly determined based on the effectiveness of advertising links, which is typically measured by active users, clicks, transactions and other actions originated from the Group's platform products. Additionally, fees are also affected by, among other factors, (i) the competitiveness of bidding for sponsored links and keywords by customers, with more intensive bidding typically leading to higher pricing and (ii) the vertical industries that customers operate in, which may result in different effectiveness and benefits of the Group's online advertising services to customers.
For advertising contracts that are charged on the cost over a time period, the Group recognizes revenue ratably over the period the advertising is provided. For contracts that are charged on the cost for performance, the revenue is estimated by the Group based on its internal data, which is confirmed with the respective customers.
Prior to year 2013, the Group also directs search traffic to search engines such as Google through its default search boxes on the Group's 360 Browsers and its default home page, 360 Personal Start-up Page. The Group receives a pre-determined fee from search engine companies based on the number of searches originated from the search boxes in 360 Browsers and 360 Personal Start-up Page, subject to a pre-determined limit, from search engine companies. The revenue is estimated by the Group based on its traffic data, which is confirmed subsequently with the search engine companies. Since the Group launched its own search engine in August 2012 and subsequently terminated its service referral agreement with Google, revenue from search referral service has decreased to zero gradually.
The Group engages in nonmonetary transactions such as to allow certain third parties to provide traffic on the non-monetization location of its platform products to show their brand or products in exchange for its brand promotion or more downloads of its platform or security products , and to allow certain third parties to bundle the Group's platform or security products with third parties' software products in exchange for more downloads of its platform or security products. The Group recognizes revenues and expenses at fair value from a nonmonetary transaction only if the fair value of the services exchanged in the transaction is determinable based on the entity's own historical practice of receiving cash, trading securities, or other consideration that is readily convertible to a known amount of cash for similar services from customers unrelated to the counterparty in the nonmonetary transaction. In 2011, the Group engaged in one nonmonetary transaction for which the fair value was determinable (see details in Note 9(ii)). Other than this transaction, for the years ended December 31, 2011, 2012 and 2013, the Group engaged in nonmonetary transactions for which the fair value was not determinable and therefore no revenues or expenses derived from these nonmonetary transactions were recognized.
	-2	Internet value-added services
The Group's internet value-added services include offering games developed by third parties and providing other internet value-added services on the Group's platforms. Prior to May 2012, the Group also offers remote technical support to paying users.
Games - The Group provides game services and generates revenue from selling in-game currency, which will be later used by game players to purchase in-game virtual items. The Group's game portfolio includes web games, client-based games and mobile games. All of the games are developed by third-party game developers and can be accessed and played by game players directly through the Group's game platform. The Group primarily views the game developers to be its customers and considers its responsibility under its agreements with the game developers to be promotion of the game developers' games. The Group generally collects payments from game players in connection with the sale of in-game currencies and remits certain agreed-upon percentages of the proceeds to the game developers and records revenue net of remittances. Revenue from the sale of in-game currency is primarily recorded net of remittances to game developers and deferred until the estimated consumption date, (i.e., the estimated date in-game currencies are consumed within the game), which is typically within a short period of time after purchase of the in-game currency. Purchases of in-game currency are not refundable after they have been sold unless there is unused in-game currency at the time a game is discontinued. Typically, a game will only be discontinued when the monthly revenue generated by a game is insignificant. To date, the Group has never been required to pay cash refunds to game players or game developers as a result of the discontinuation of a game.
Other internet value-added services - The Group provides online lottery purchase services and serves as an agent for providing online distribution services and payment collection services on behalf of third-parties, such as collection payment for mobile charges, e-books and etc. The Group provides payment collection services mainly through third-party professional payment and settlement institutions. The Group generally charges commission as a percentage of the gross proceeds or collection amount, and the revenue is estimated by the Group based on its internal system, which is confirmed with the respective cooperators.
Remote technical support - The Group provides live technical assistance on a broad range of computer issues relating to security and performance optimization through remote access to users' computers. The Group generally charges fees on a per case basis for this service and also provides monthly and annual subscriptions. For services charged on a per case basis, the Group recognizes revenue when the service is provided. For monthly and annual subscriptions, the Group recognizes revenue ratably over the life of the subscription. Starting from May 2012, the Group offers remote technical support services for free and refunds prepaid fees to users.
Sales of third party anti-virus software
The Group purchases software, such as anti-virus software, from third-party software developers for online distribution to users. The Group recognizes revenue when the activation code of the software is delivered. The Group evaluates its software sales contracts to determine whether to recognize revenues on a gross basis or net of costs of obtaining the associated software. The determination is based upon an assessment as to whether the Group acts as a principal or agent when providing the sales. After an agreement with a third-party developer was expired in April 2012, the Group's sales of third party anti-virus software has been insignificant.
Deferred revenue
Deferred revenue primarily includes cash received in advance from customers or end users and unrecognized license fee related to a license granted under a nonmonetary transaction as described in Note 9(ii), and deferred subsidy income. The unused cash balances remaining in customers or users' accounts are recorded as a liability. Deferred revenues related to prepayments from third party customers or end users will be recognized as revenue when all of the revenue recognition criteria are met, and deferred revenue related to license fee will be recognized as revenue based on the contract term.
Costs of revenues
Cost of revenues primarily consists of business tax, value added tax ("VAT") and related surcharges, payment collection costs, traffic acquisition costs, salaries and benefits, bandwidth costs, depreciation of equipment and revenue sharing to third party partners.
Business tax and related surcharges by various Chinese local tax authorities are incurred at rates ranging from 3.39% to 8.70% on revenue generated from providing services.
In July 2012, the Ministry of Finance and the State Administration of Taxation jointly issued a circular regarding the pilot collection of VAT in lieu of business tax in certain areas and industries in the PRC. Such VAT pilot program was to be phased in Beijing and Tianjin in September and December 2012, respectively. Starting from September 1, 2012, certain subsidiaries and VIEs of the Group became subject to VAT and related surcharges by various Chinese local tax authorities at rates ranging from 3.00% to 19.04% on revenue generated from providing services which were previously subject to business tax.
Business tax and VAT included in revenues and cost of revenues for the years ended December 31, 2011, 2012 and 2013 were $9,078, $18,434 and $39,909, respectively.
Product development expenses
The product development expenses primarily consist of the research and development expenses and expenses incurred for strengthening the existing products. Product development primarily focused on the development and enhancement of security products, cloud-based services, search engine related products, mobile internet products and other internet products, platforms and services.
Product development expenses include personnel-related expenses, bandwidth, license and technical service fees, depreciation of property and equipment and amortization of acquired intangible assets. The Group expenses product development costs as incurred.
Advertising costs
Advertising costs are expensed as incurred. The Group incurred advertising costs of $7,843, $21,082 and $62,301 for the years ended December 31, 2011, 2012 and 2013, respectively, which were recorded as a component of selling and marketing expenses in the accompanying consolidated statements of operations.
Operating leases
Leases where the rewards and risks of ownership of assets primarily remain with the lessor are accounted for as operating leases. Payments made under operating leases are charged to the consolidated statements of operations on a straight-line basis over the lease periods.
Subsidy income
Government subsidy is recorded as a liability in deferred revenue when received, and recognized as subsidy income when the project is inspected and confirmed by the government, or it is not subject to future return or reimbursement. The Group recognized subsidy income of $151, $2,570 and $2,349 for the years ended December 31, 2011, 2012 and 2013, respectively.
Income taxes
The Group follows the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial reporting and tax basis of assets and liabilities using enacted tax rates that will be in effect for the period in which the differences are expected to reverse. The Group records a valuation allowance against the amount of deferred tax assets that it determines is not more-likely-than-not of being realized. The effect on deferred taxes of a change in tax rates is recognized in the consolidated statements of operations in the period that includes the enactment date.
The impact of an uncertain income tax position on the income tax return is recognized at the largest amount that is more-likely-than-not to be sustained upon audit by the relevant tax authority. An uncertain income tax position will not be recognized if it has less than a 50% likelihood of being sustained. Interest and penalties on income taxes will be classified as a component of the provisions for income taxes.
Net income per share
Basic net income per share is computed by dividing net income attributable to ordinary shareholders by the weighted average number of ordinary shares outstanding during the year excluding any outstanding ordinary shares that are contingently refundable subject to the satisfaction of both the service and performance condition on the nonvested shares. Diluted net income per share reflects the potential dilution that could occur if securities or other contracts to issue ordinary shares were exercised or converted into ordinary shares.
The Company computes earnings per Class A and Class B ordinary shares using the two-class method. The unvested portions of nonvested shares are participating securities as all outstanding nonvested shares are entitled to nonforfeitable dividends that participate in undistributed earnings with ordinary shares. Since the nonvested shares are considered participating securities, the nonvested shares issued by the Company are required to apply the two-class method when computing basic earnings per share.
The Group has share options, nonvested shares and convertible senior notes which could potentially dilute basic earnings per share in the future. To calculate the number of shares for diluted net income per share, the effect of the share options is computed using the treasury stock method. The dilutive effect of the convertible senior notes is computed using as-if converted method.
Foreign currency translation
The functional and reporting currency of the Company is the United States dollar ("U.S. dollar"). The financial records of the Company's subsidiaries, VIEs and VIEs' subsidiaries located in the PRC are maintained in its local currency, the Renminbi ("RMB") which is the functional currency of these entities. The financial records of the Company's subsidiaries located in Hong Kong are maintained in U.S. dollar which is the functional currency of these entities.
Monetary assets and liabilities denominated in currencies other than the functional currency are translated into the functional currency at the rates of exchange ruling at the balance sheet date. Transactions in currencies other than the functional currency during the year are converted into functional currency at the applicable rates of exchange prevailing when the transactions occurred. Transaction gains and losses are recognized in the consolidated statements of operations.
The Group's entities with functional currency of RMB translate their operating results and financial position into the U.S. dollar, the Company's reporting currency. Assets and liabilities are translated using the exchange rates in effect on the balance sheet date. Equity amounts are translated at historical exchange rates, and revenues, expenses, gains and losses are translated using the average rate for the year. Translation adjustments are reported as cumulative translation adjustments and are shown as a separate component of other comprehensive income in the consolidated statements of changes in equity and comprehensive income.
Comprehensive income
Comprehensive income of the Group includes the cumulative foreign currency translation adjustments and net income for the year. Comprehensive income is reported in the statements of comprehensive income.
Share-based compensation
Share-based compensation with employees is measured based on the grant date fair value of the equity instrument. The Group recognizes the compensation costs net of an estimated forfeiture rate using the straight-line method, over the requisite service period of the award, which is generally the vesting period of the award. The estimate of forfeitures will be adjusted over the requisite service period to the extent that actual forfeitures differ, or are expected to differ, from such estimates. Changes in estimated forfeitures will be recognized through a cumulative catch-up adjustment in the period of change and will also impact the amount of share-based compensation expense to be recognized in future periods.
Share awards issued to nonemployees are measured at fair value at the earlier of the commitment date or the date the services is completed and recognized over the period the service is provided or as goods is received.
The Group uses the Black-Scholes or Binomial-Model option pricing model to measure the value of options granted to employees and nonemployees at each grant date or measurement date.
Treasury stock
Treasury stock represents ordinary shares repurchased by the Group that are no longer outstanding and are held by the Group. The repurchase of ordinary shares is accounted for under the cost method whereby the entire cost of the acquired stock is recorded as treasury stock.
Risks and uncertainties
The Group participates in a dynamic industry with rapid changes in regulations, technology trends, customer demand and competition and believes that changes in any of the following areas could have a material adverse effect on the Group's future financial position, results of operations, or cash flows: advances and trends in new technologies and industry standards; changes in certain strategic relationships or customer relationships; regulatory or other PRC related factors; risks associated with the Group's ability to attract and retain certain necessary employees to support its growth; risks associated with the Group's ability to keep and increase the user base; risks associated with the Group's growth strategies and general risks associated with the internet security industry, and risks surrounding pending litigations.
Concentration of credit risk
Financial instruments that potentially expose the Group to concentrations of credit risk consist primarily of cash and accounts receivable. The Group places its cash with financial institutions with high-credit ratings and quality. The Group conducts credit evaluations of customers and generally does not require collateral or other security from their customers. The Group maintains reserves for potential credit losses.
Details of the customers that account for 10% or more of total revenues are as follow:
		Year ended December 31,
		2011			2012			2013
Customer
A			10	%		5	%		*-
B			11	%		10	%		*-
Details of the customers accounting for 10% or more of accounts receivable are as follows:
		December 31,
		2012			2013
Customer
B			29	%		32	%
C			12	%		*-
“*” means less than 10%
Newly adopted accounting pronouncements
In July 2012, the FASB has issued an authoritative pronouncement related to testing indefinite-lived intangible assets, other than goodwill, for impairment. Under the pronouncement, entities testing indefinite-lived intangible assets for impairment would have the option of performing a qualitative assessment before calculating the fair value of the asset. If an entity determines, on the basis of qualitative factors, that the indefinite-lived intangible asset is not more likely than not impaired, a quantitative fair value calculation would not be needed. The amendments are effective for annual and interim impairment tests performed for fiscal years beginning after September 15, 2012. The adoption of this guidance did not have a significant effect on the Group's consolidated financial statements.
In February 2013, the FASB issued an authoritative pronouncement related to reporting of amounts reclassified out of accumulated other comprehensive income, to improve the transparency of reporting these reclassifications. Other comprehensive income includes gains and losses that are initially excluded from net income for an accounting period. Those gains and losses are later reclassified out of accumulated other comprehensive income into net income. The amendments in this ASU do not change the current requirements for reporting net income or other comprehensive income in financial statements. All of the information that this ASU requires already is required to be disclosed elsewhere in the financial statements under US GAAP.
The new amendments will require an organization to:
• Present (either on the face of the statement where net income is presented or in the notes) the effects on the line items of net income of significant amounts reclassified out of accumulated other comprehensive income—but only if the item reclassified is required under US GAAP to be reclassified to net income in its entirety in the same reporting period.
• Cross-reference to other disclosures currently required under US GAAP for other reclassification items (that are not required under US GAAP) to be reclassified directly to net income in their entirety in the same reporting period. This would be the case when a portion of the amount reclassified out of accumulated other comprehensive income is initially transferred to a balance sheet account (e.g., inventory for pension-related amounts) instead of directly to income
or expense.
The amendments apply to all public and private companies that report items of other comprehensive income. Public companies are required to comply with these amendments for all reporting periods (interim and annual). The amendments are effective for reporting periods beginning after December 15, 2012, for public companies. Early adoption is permitted. The Group adopted this pronouncement on January 1, 2013 which did not have a significant impact on its consolidated financial statements.
Recently issued accounting pronouncements not yet adopted
In July 2013, the FASB issued a pronouncement which provides guidance on financial statement presentation of an unrecognized tax benefits when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. The FASB’s objective in issuing this Accounting Standards Updates (‘‘ASU’’) is to eliminate diversity in practice resulting from a lack of guidance on this topic in current US GAAP. The amendments in this ASU state that an unrecognized tax benefit, or a portion of an unrecognized tax benefit, should be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward, except as follows. To the extent a net operating loss carryforward, a similar tax loss, or a tax credit carryforward is not available at the reporting date under the tax law of the applicable jurisdiction to settle any additional income taxes that would result from the disallowance of a tax position or the tax law of the applicable jurisdiction does not require the entity to use, and the entity does not intend to use, the deferred tax asset for such purpose, the unrecognized tax benefit should be presented in the financial statements as a liability and should not be combined with deferred tax assets.
This ASU applies to all entities that have unrecognized tax benefits when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists at the reporting date. The amendments in this ASU are effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. Early adoption is permitted. The amendments should be applied prospectively to all unrecognized tax benefits that exist at the effective date. Retrospective application is permitted.
The Group does not expect the adoption of this guidance will have a significant effect on its consolidated financial statements.

Acquisition

Acquisition	12 Months Ended
	Dec. 31, 2013
Acquisition [Abstract]	'
Acquisition	'
		3	ACQUISITIONS
		-1	Acquisition of internet security business
	In April 2012, the Group made an investment of $1,983, representing 20% ownership, to an internet service company.  The investment was accounted for as equity method investment since the Group has significant influence over the acquiree.  In September 2013, the Group acquired another 60% equity interest from the third-party shareholders for a cash consideration of $7,966.  The acquisition provided synergies with the existing business.  At the acquisition date, the fair value of the 20% equity investment was valued at $1,831 by the management with the assistance of an independent valuation firm. The difference of $120 between the fair value of the 20% equity interest and its book value was recorded as gain from equity method investments.  The $7,966 cash consideration was paid in 2013.
	The acquisition was recorded using the acquisition method of accounting and, accordingly, the acquired assets and liabilities were recorded at their fair market values at the date of acquisition. The total purchase price of $7,966, representing 60% ownership, was allocated as follows:
			US$
	Cash		$	387
	Other net assets acquired, excluding intangible assets and related deferred tax liabilities			(9	)
	Intangible assets
	Technology			2,451
	Trade mark			866
	Deferred tax liability			(829	)
	Goodwill			8,762
	Fair value of 20% equity interests owned by the Group			(1,831	)
	Non-Controlling Interest			(1,831	)
	Total		$	7,966
	The intangible assets valuations for the acquisitions described above were based on valuation analysis prepared by the management with the assistance of an independent third party valuation firm. The valuation analysis utilizes and considers generally accepted valuation methodologies such as the income, market and cost approaches. The Group has incorporated certain assumptions which include projected cash flows and replacement costs.
	The goodwill is mainly attributable to intangible assets that cannot be recognized separately as identifiable assets under US GAAP and comprise (a) the assembled work force and (b) the expected but unidentifiable business growth as a result of the synergy resulting from the acquisition.
	The following pro forma information summarizes the effect of the acquisition, as if it had occurred as of January 1, 2012. This pro forma information is presented for information purposes only. It is based on historical information and does not purport to represent the actual results that may have occurred had the Group consummated the acquisition on January 1, 2012, nor is it necessarily indicative of future results of operations of the consolidated enterprises:
			Year ended December 31,
			2012			2013
			(Unaudited)			(Unaudited)
	Pro forma revenue		$	329,591		$	671,429
	Pro forma net income		$	45,938		$	98,582
	Pro forma earnings per ordinary share-basic		$	0.26		$	0.55
	Pro forma earnings per ordinary share-diluted		$	0.25		$	0.51
	The operating results of this acquired business have been included in the Group's consolidated financial statements since the date of acquisition. It contributed net revenue of $119, and net loss of $1,333 to the Group's consolidated statement of operations for the year ended December 31, 2013.
		-2	Acquisition of overseas internet service business
	In July 2013, the Group acquired 51% equity interest of an overseas internet service company, from its three shareholders with consideration of $7,864 which was settled in the form of 204,466 ordinary shares of the Company, based upon the closing price of the Company's ADSs at the acquisition date. The acquisition allowed the Group to extend its oversea business and provide synergies with its existing business. One of the selling shareholders is a related party to the Group (see note 23(3) (i)).
	The acquisition was recorded using the acquisition method of accounting and, accordingly, the acquired assets and liabilities were recorded at their fair market value at the date of acquisition. The total purchase price of $7,864, representing 51% ownership, was allocated as follows:
			US$
	Cash		$	687
	Other net assets acquired, excluding intangible assets and the related deferred tax liabilities			1,512
	Intangible assets
	Customer relationship			3,147
	Technology			535
	User base			129
	Goodwill			8,319
	Deferred tax liability			(1,069	)
	Non-Controlling Interest			(5,396	)
	Total		$	7,864
	The intangible assets valuations for the acquisitions described above were based on valuation analysis prepared by the management with the assistance of an independent third party valuation firm. The valuation analysis utilizes and considers generally accepted valuation methodologies such as the income, market and cost approaches. The Group has incorporated certain assumptions which include projected cash flows and replacement costs.
	The goodwill is mainly attributable to intangible assets that cannot be recognized separately as identifiable assets under US GAAP and comprise (a) the assembled work force and (b) the expected but unidentifiable business growth as a result of the synergy resulting from the acquisition.
	The following pro forma information summarizes the effect of the acquisition, as if it had occurred as of January 1, 2012. This pro forma information is presented for information purposes only. It is based on historical information and does not purport to represent the actual results that may have occurred had the Group consummated the acquisitions on January 1, 2012, nor is it necessarily indicative of future results of operations of the consolidated enterprises:
			Year ended December 31,
			2012			2013
			(Unaudited)			(Unaudited)
	Pro forma revenue		$	336,215		$	675,981
	Pro forma net income		$	44,940		$	99,001
	Pro forma earnings per ordinary share-basic		$	0.25		$	0.55
	Pro forma earnings per ordinary share-diluted		$	0.24		$	0.51
	The operating results of this acquired business have been included in the Group's consolidated financial statements since the date of acquisition. It contributed net revenue of $3,443, and net loss of $2,724 to the Group's consolidated statement of operations for the years ended December 31, 2013.
		-3	Acquisition of internet service business
	In November 2013, the Group acquired 51% equity interest of an internet service company, by contributing $10,000 as registered capital to the acquiree. The Group obtained the control over the acquiree as a result of the capital contribution. The acquisition allowed the Company to enhance its service offerings and provide synergies with the existing business. The consideration was fully paid in 2013.
	The acquisition was recorded using the acquisition method of accounting and, accordingly, the acquired assets and liabilities were recorded at their fair market values at the date of acquisition. The total purchase price of $10,000, representing 51% ownership, was allocated as follows:
			US$
	Cash		$	10,169
	Other net assets acquired, excluding intangible assets and related deferred tax liabilities			80
	Intangible assets
	Technology			1,188
	User base			27
	Goodwill			6,346
	Deferred tax liability			(304	)
	Non-Controlling Interest			(7,506	)
Total		$	10,000
The intangible assets valuations for the acquisitions described above were based on valuation analysis prepared by the management with the assistance of an independent third party valuation firm. The valuation analysis utilizes and considers generally accepted valuation methodologies such as the income, market and cost approaches. The Group has incorporated certain assumptions which include projected cash flows and replacement costs.
The goodwill is mainly attributable to intangible assets that cannot be recognized separately as identifiable assets under US GAAP and comprise (a) the assembled work force and (b) the expected but unidentifiable business growth as a result of the synergy resulting from the acquisition.
The following pro forma information summarizes the effect of the acquisition, as if it had occurred as of January 1, 2012. This pro forma information is presented for information purposes only. It is based on historical information and does not purport to represent the actual results that may have occurred had the Group consummated the acquisitions on January 1, 2012, nor is it necessarily indicative of future results of operations of the consolidated enterprises:
		Year ended December 31,
		2012			2013
		(Unaudited)			(Unaudited)
Pro forma revenue		$	329,032		$	671,180
Pro forma net income		$	46,471		$	97,658
Pro forma earnings per ordinary share-basic		$	0.26		$	0.54
Pro forma earnings per ordinary share-diluted		$	0.25		$	0.51
The operating results of this acquired business have been included in the Group's consolidated financial statements since the date of acquisition. It contributed net revenue of $nil, and net loss of $958 to the Group's consolidated statement of operations for the years ended December 31, 2013.
	-4	Other acquisitions
Year 2011
	(i)	In June 2011, the Group acquired the remaining 65% equity interest in one of its equity method investees, an internet service business with cash consideration of $618, fully paid in 2011 and goodwill of $338 was resulted from the acquisition; and
	(ii)	In June 2011, the Group acquired the entire equity interest of an anti-virus business with cash consideration of $491, fully paid in 2011 and goodwill of $120 was resulted from such acquisition.
Year 2012
In September 2012, the Group acquired the remaining 65% equity interest in one of its equity method investees, a software development business with cash consideration of $312. $185 cash consideration was paid during 2012 and the remaining $127 was paid in 2013.
Year 2013
	(i)	In May, 2013, the Group acquired an internet service business with cash consideration of $1,790, which was fully paid in 2013. Goodwill of $1,248 was recognized from this acquisition; and
	(ii)	In May, 2013, the Group acquired 51% equity interest of a data center business ("Entity P") with cash consideration of $3,257, which was fully paid in 2013. Goodwill of $317 was recognized from this acquisition;

Disposal_of_a_Subsidiary

Disposal of a Subsidiary	12 Months Ended
	Dec. 31, 2013
Disposal of a Subsidiary [Abstract]	'
Disposal of a Subsidiary	'
		4	DISPOSAL OF A SUBSIDIARY
	In January 10, 2012, the Group sold its entire 53.5% equity interest of a subsidiary of VIEs to its noncontrolling interest shareholders for a cash consideration of $4,207. The Group recognized a gain from the disposal with an amount of $3,566 in year 2012.
	On September 30, 2013, the Group disposed 47.8% of equity interests in one of its subsidiaries to the noncontrolling interest shareholder of such subsidiary and hence, reduced its equity interest from 77.8% to 30.0%. Since the Group lost its controlling interest in but is able to exercise significant influence over it, it was deconsolidated and accounted for as an equity method investee of the Group upon consummation of the transaction. The Group recognized a loss from the deconsolidation with an amount of $1,144 in year 2013.

Restricted_Cash

Restricted Cash	12 Months Ended
	Dec. 31, 2013
Restricted Cash [Abstract]	'
Restricted Cash	'
		5	RESTRICTED CASH
	Restricted cash consists of the following:
			December 31,
			2012		2013
	Deposits for registration of new subsidiaries of VIEs (i)		$	1,605	$	1,652
	Deposit used to secure for bank's acceptance bills in relation to payment for the construction of a building			-		416
	Deposits used to secure for application of an operation right			300		300
	Total		$	1,905	$	2,368
		(i)	The balance represented the deposits placed in certain escrow accounts for registration of new VIEs’ wholly owned subsidiaries.

Availableforsale_Investment

Available-for-sale Investment	12 Months Ended
	Dec. 31, 2013
Available-for-sale Investment [Abstract]	'
Available-for-sale Investment	'
		6	AVAILABLE-FOR-SALE INVESTMENT
	Amount represents the convertible loan with an amount of $495 provided to one of the Group’s cost method investees in June 2013. The Group has the right to convert the convertible loan into equity interest of such investee upon achievement of certain targets by the investee in year 2014. The Group determined that the carrying value of such convertible loan is approximate to its fair value as of December 31, 2013. Subsequent to December 31, 2013, the Group decided to exercise the conversion right to increase its equity interest in the investee and the conversion is currently in process.

Accounts_Receivable

Accounts Receivable	12 Months Ended
	Dec. 31, 2013
Accounts Receivable [Abstract]	'
Accounts Receivable	'
		7	ACCOUNTS RECEIVABLE
	Accounts receivable consists of the following:
			December 31,
			2012			2013
	Accounts receivable		$	23,804		$	54,743
	Allowance for doubtful accounts			(213	)		(145	)
	Accounts receivable, net		$	23,591		$	54,598
	Movement of allowance for doubtful accounts is as follows:
			December 31,
			2011			2012			2013
	Balance at beginning of year		$	14		$	68		$	213
	Charge to expenses			51			154			157
	Write offs during the year			-			(10	)		(229	)
	Exchange rate differences			3			1			4
	Balance at end of year		$	68		$	213		$	145

Prepaid_expenses_and_other_cur

Prepaid expenses and other current assets	12 Months Ended
	Dec. 31, 2013
Prepaid expenses and other current assets [Abstract]	'
Prepaid expenses and other current assets	'
		8	PREPAID EXPENSES AND OTHER CURRENT ASSETS
			December 31,
			2012		2013
	Guarantee loan to employees related to exercise of share options (i)		$	753	$	29,188
	Receivables of exercise cost share options (ii)			4,907		301
	Prepaid principal for investments (iii)			1,003		10,534
	Advance to suppliers			4,205		9,804
	Deductible VAT Input			7,895		9,650
	Prepaid marketing promotion fee			515		7,034
	Interest receivable			1,086		3,219
	Advance related to employees			1,011		2,146
	Others			5,427		8,662
	Total		$	26,802	$	80,538
		(i)	Amount represents the individual income tax paid by the Group on behalf of employees associated with the options and nonvested shares granted by the Company. Such receivable is secured by share options or nonvested shares held by the employees, and will be repaid to the Company when the options are exercised and related ordinary shares are sold.
		(ii)	Amount represents the exercise cost to be received by the Group from a trading institution after the Group's employees exercised their stock options through such institution.
		(iii)	The Group made several payments to establish new companies with other independent third parties. The prepayments will be recorded as long-term investments when the investees are legally established.

Longterm_Investments

Long-term Investments	12 Months Ended
	Dec. 31, 2013
Long-term Investments [Abstract]	'
Long-term Investments	'
		9	LONG-TERM INVESTMENTS
			December 31,
			2012			2013
	Cost method investments:
	An internet service company, Investee D (i)		$	-		$	15,000
	Others			13,989			33,306
	Less: impairment loss on long-term investments (iii)			(1,427	)		(2,294	)
	Cost method investments, net		$	12,562		$	46,012
	Equity method investments:
	An internet security company, Investee E (ii)		$	1,761		$	24,099
	Others			14,777			19,264
	Less: impairment loss on long-term investments (iv)			(1,541	)		(5,082	)
	Equity method investments, net			14,997			38,281
	Total		$	27,559		$	84,293
	The Group held equity interests ranging from 1.5% to 19% in certain cost method investments, majority of which is engaged in internet technology industry, mobile application development industry, and web-game industry. The Group used cost method of accounting to account for the investments with equity interest below 20% when the Group does not have the ability to exercise significant influence. During 2013, the Group sold two cost method investments and recognized a total gain of $427. During 2012, the Group sold certain of its equity interests in two cost method investments and recognized a total gain of $3,432. No disposal of cost method investments occurred in 2011.
	The Group held equity interests ranging from 4.5% to 49% in certain equity method investments, majority of which is engaged in internet technology industry, mobile game development industry, mobile application development industry. The Group used the equity method of accounting to account for the investments with equity interest between 20% and 50% when the Group has the ability to exercise significant influence but does not have controlling interest over the investments. The Group shared loss of $437, $4,845 and $2,747 from its equity method investments during the years end December 31, 2011, 2012 and 2013, respectively. During 2013, the Group sold two equity method investments and certain of its equity interests in one equity method investment and recognized a total gain of $15,380. During 2012, the Group sold two equity method investments and recognized a total gain of $1,334. No disposal of equity method investments occurred in 2011.
		(i)	In December 2013, the Group invested in Investee D to purchase 4.13% of its ordinary shares for purchase prices of $15,000. The Group used the cost method of accounting to record these investments since the Group does not have the ability to exercise significant influence over the operating and financing activities. The management of the Group determined that there was no impairment on such investments during the year ended December 31, 2013.
		(ii)	In November 2011, the Group entered into a nonmonetary transaction with Investee E. The Group provides the license for using the Group's certain technology licenses to Investee E in exchange for its 30% equity interest in the form of preferred shares. The Group also needs to provide continuous technical support to the investee for ten years. Because the fair value of the licenses is more readily determinable, the Group recorded the transaction based on the fair value of the license which was valued with the assistance of a third-party valuation firm. The fair value was determined as $3,000. The transaction was accounted for as an equity method investment since the Group has the ability to exercise significant influence over the operating and financing activities of Investee E. The partial gain of the nonmonetary transaction was recorded as deferred revenue and is amortized ratably over the ten year contract period. In June 2012, the Group made an additional investment in Investee E for an aggregate price of $2,140 in cash to avoid diluting in its series B financing. In December 2013, the Group made another additional investment in Investee E for an aggregate price of $25,000 in cash in its series C financing. As of December 31, 2013, the Group held 40.8% equity interest in Investee E. The Group recognized $142, $2,337 and $2,661 share of loss in 2011, 2012 and 2013, respectively. The management of the Group determined that there was no impairment on such investment during the years ended December 31, 2011, 2012 and 2013.
		(iii)	The Group reviews its cost method investments for impairment whenever an event or circumstance indicates that an other-than-temporary impairment has occurred. The Group considers available quantitative and qualitative evidence in evaluating potential impairment of its cost method investments. An impairment charge is recorded if the cost of an investment exceeds its fair value and such excess is determined to be other-than-temporary. The Group estimated the fair value of these investee companies based on discounted cash flow approach. Factors the Group considers in making such a determination include general market conditions, the duration and the extent to which the fair value of an investment is less than its cost, and the Group's intent and ability to hold such investment. As a result of the assessment process for its cost method investments, the Group recognized impairment charge of $666, $761 and $867 million in 2011, 2012 and 2013, respectively for certain cost method investments as their financial positions and performance of these investee companies are deteriorating and the Group does not expect them to generate any positive future cash flows. Accordingly, the Group estimated the fair values of these investee companies would be minimal.
		(iv)	An impairment charge is recorded if the carrying amount of the equity method investment exceeds its fair value and this condition is determined to be other-than-temporary. The Group estimated the fair value of these investee companies based on discounted cash flow approach which requires significant judgments, including the estimation of future cash flows, which is dependent on internal forecasts, the estimation of long term growth rate of a company’s business, the estimation of the useful life over which cash flows will occur, and the determination of the weighted average cost of capital. Certain of the equity method investments experience a deteriorating financial position and performance and the Group does not expect them to generate any positive future cash flows. Accordingly, the Group accrued an impairment charge of $236, $1,541 and $4,137 in 2011, 2012 and 2013 on these equity method investments based on their fair value which would be minimal.

Property_and_equipment_net

Property and equipment, net	12 Months Ended
	Dec. 31, 2013
Property and equipment, net [Abstract]	'
Property and equipment, net	'
		10	PROPERTY AND EQUIPMENT, NET
			December 31,
			2012		2013
	Computer equipment and application software		$	81,023	$	149,877
	Building (i)			45,050		46,471
	Office building related facility and machines (i)			13,212		14,022
	Furniture and vehicles			4,422		4,672
	Leasehold improvements			1,038		1,354
	Construction in Progress (ii)			-		5,469
				144,745		221,865
	Less: Accumulated depreciation and amortization			18,710		58,001
	Property and equipment, net		$	126,035	$	163,864
		(i)	In August 2012, the Group entered into a series of definitive agreements to purchase two parcels of office buildings and the associated land use rights with an area of approximately 69,205 square meters in Chaoyang District, Beijing, China for a total cash consideration of $222 million. The Group completed the acquisition of one parcel of the buildings in 2012 and the acquisition of the other parcel of buildings was in process as of December 31, 2013. The Group capitalized the related building cost of $43,927 and the cost for the facilities of the first parcel of building of $13,212 in the year ended December 31, 2012. No building cost and facilities cost were capitalized in year 2013.
		(ii)	As part of the acquisition of Entity P in 2013 as described in Note 3(4), the Group acquired a building under construction at Henan Province of China.
	Depreciation and amortization expenses for the years ended December 31, 2011, 2012 and 2013 were $3,393, $14,768 and $38,453, respectively.

Land_Use_Rights_Net

Land Use Rights, Net	12 Months Ended
	Dec. 31, 2013
Land Use Rights, Net [Abstract]	'
Land Use Rights, Net	'
		11	LAND USE RIGHTS, NET
			December 31,
			2012		2013
	Land use rights		$	73,785	$	77,590
	Less: accumulated depreciation and amortization			140		1,892
	Land use rights, net		$	73,645	$	75,698
	In December 2012, the Group acquired land use rights associated with the newly acquired office building in Chaoyang District, Beijing, China (see Note 10 (i) for detail). The land certificate will expire as of December 8, 2056. The Group is in the process of obtaining the certificate of the land use rights.
	In May 2013, the Group owned a land use right of $1,632 at Henan Province of China through the acquisition of Entity P as described in Note 10 (ii). Such land certificate will expire as of December 11, 2061.
	The Group amortizes the cost of acquired land use rights on a straight-line basis starting from the acquisition date till the expiration date of the certificate of the land use rights. Amortization expenses for land use rights totaled $140 and $1,714 for the years ended December 31, 2012 and 2013.
	Future amortization expense is $1,760 per year for each of the next five years through December 31, 2018 and after.

Acquired_Intangible_Assets_Net

Acquired Intangible Assets, Net	12 Months Ended
	Dec. 31, 2013
Acquired Intangible Assets, Net [Abstract]	'
Acquired Intangible Assets, Net	'
		12	ACQUIRED INTANGIBLE ASSETS, NET
	The gross carrying amount, accumulated amortization and net carrying amount of the acquired intangible assets are as follows:
	Definite-lived intangible assets
			December 31,
			2012			2013
	Definite-lived:
	Domain names		$	2,426		$	2,482
	Source code			1,754			1,662
	Technology			6,999			12,013
	Non-compete agreement			3,933			3,985
	Operating License			610			1,768
	Trademarks			77			79
	User Base			-			157
	Customer relationship			-			2,973
	Total acquired definite-lived intangible assets			15,799			25,119
	Less: Accumulated amortization
	Domain names			(423	)		(859	)
	Source code			(821	)		(1,050	)
	Technology			(1,872	)		(3,450	)
	Non-compete agreement			(299	)		(1,584	)
	Trademarks			(2	)		(29	)
	Operating license			-			(235	)
	User base			-			(8	)
	Customer relationship			-			(507	)
	Accumulated amortization			(3,417	)		(7,722	)
	Less: Impairment loss
	Domain names			(411	)		(424	)
	Source code			(158	)		(72	)
	Technology			(673	)		(887	)
	Accumulated impairment loss			(1,242	)		(1,383	)
	Acquired definite-lived intangible assets, net		$	11,140		$	16,014
	Amortization expenses for the years ended December 31, 2011, 2012 and 2013 were $834, $1,689 and $4,176, respectively. Amortization expenses for the years ending December 31, 2014, 2015, 2016, 2017 and 2018 and after are expected to be $5,075, $4,484, $1,826, $1,211 and $3,418, respectively.
	Intangible assets with determinable useful lives are evaluated for recoverability whenever events or changes in circumstances indicate that their carrying amounts may not be recoverable. The Group measures recoverability of these assets to be held and used as part of reporting unit by comparing the carrying amount of an asset to the future undiscounted net cash flows expected to be generated by the asset. If the assets are determined as impaired, the impairment will equal the amount by which the carrying value of the assets exceeds the fair value of the assets. As a result of the impairment analysis, the Group recognized an impairment loss of $87, $1,151 and $107 for the year ended December 31, 2011, 2012 and 2013, respectively for intangible assets with determinable useful lives.
	Indefinite-lived intangible assets:
			December 31,
			2012			2013
	Indefinite-lived:
	Domain names		$	360		$	371
	Trademarks			1,288			2,200
	Total acquired indefinite-lived intangible assets			1,648			2,571
	Less: Impairment loss
	Domain names			(281	)		(288	)
	Trademarks			(197	)		(1,049	)
	Accumulated impairment loss			(478	)		(1,337	)
	Acquired indefinite-lived intangible assets, net		$	1,170		$	1,234
	On December 31 of each year, the Group evaluated the remaining useful life of the intangible assets with indefinite lives to determine whether events and circumstances continue to support an indefinite useful life.
	The Group then performs an impairment assessment on intangible assets with indefinite lives on December 31 of each year by comparing the fair value with its carrying value. The fair value of intangible assets with indefinite lives was estimated based on the discounted value of estimated future cash flows. Based on the assessment, the Group determined the excess in the carrying value of indefinite-lived intangible asset over its fair value and recognized an impairment loss of nil, $197 and $841 for the years ended December 31, 2011, 2012 and 2013, respectively.

Goodwill

Goodwill	12 Months Ended
	Dec. 31, 2013
Goodwill [Abstract]	'
Goodwill	'
		13	GOODWILL
			2012		2013
	Beginning balance		$	4,580	$	4,628
	Goodwill acquired in acquisitions of business			-		24,992
	Exchange rate differences			48		(111	)
	Ending balance		$	4,628	$	29,509
	The Group assessed the qualitative factors to determine it is not more likely than not that the fair value of each reporting unit is less than its respective carrying amount. There was no impairment of goodwill during the years ended December 31, 2011, 2012 and 2013.

Accrued_expenses_and_other_cur

Accrued expenses and other current liabilities	12 Months Ended
	Dec. 31, 2013
Accrued expenses and other current liabilities [Abstract]	'
Accrued expenses and other current liabilities	'
		14	ACCRUED EXPENSES AND OTHER CURRENT LIBILITIES
			December 31,
			2012		2013
	Payable for purchasing plant, property and equipment		$	59,703	$	20,419
	Payable for purchasing intangible assets			3,340		442
	Payable for purchasing land use rights			62,717		-
	Payroll related payable			13,446		19,217
	Accrued agent rebates and profit sharing cost			1,723		16,891
	Accrued marketing promotion expenses			6,102		13,965
	Other tax payable			2,616		12,094
	Deposits from advertising customers			1,376		10,060
	Accrued bandwidth			9,052		8,566
	Accrued professional service fee			3,145		6,640
	Accrued interest expenses of convertible senior notes (see note 17)			-		4,808
	Other current liabilities			5,326		7,316
	Total		$	168,546	$	120,418

Deferred_Revenue

Deferred Revenue	12 Months Ended
	Dec. 31, 2013
Deferred Revenue [Abstract]	'
Deferred Revenue	'
		15	DEFERRED REVENUE
			December 31,
			2012		2013
	Deferred revenue - current:
	Deferred revenue from customers (i)		$	14,915	$	31,503
	Deferred revenue for system development services (ii)			1,102		2,266
	Deferred subsidy income (iii)			4,093		11,503
	Deferred license fee (iv)			210		210
	Deferred reimbursement of ADS depositary service (v)			729		1,150
	Total deferred revenue - current		$	21,049	$	46,632
	Deferred revenue - noncurrent
	Deferred license fee (iv)		$	1,654	$	1,444
	Deferred revenue for system development services (ii)			408		168
	Deferred subsidy income (iii)			3,059		495
	Deferred reimbursement of ADS depositary service (v)			1,641		1,437
	Total deferred revenue - noncurrent		$	6,762	$	3,544
		(i)	Deferred revenue from customers mainly represents payments received from (1) advertising customers before the services were provided by the Group; and (2) game players before the in-game currency were consumed.
		(ii)	Deferred revenue for system development services represents payments received from third party customers in relation to the service to be provided by the Group which is subject to the customers' inspection and acceptance.
		(iii)	The Group received subsidies from the local government for web-security related research and development projects. The amount was deferred since the projects are subject to final inspection upon the completion.
		(iv)	Deferred license fee was related to the nonmonetary transaction as described in Note 9(ii).
		(v)	Deferred reimbursement of ADS depositary service represents the cash received from the Bank of New York Mellon as reimbursement of its ADS depositary service, which will be recognized ratably over the ADS contract term.

ShortTerm_Loan

Short-Term Loan	12 Months Ended
	Dec. 31, 2013
Short-Term Loan [Abstract]	'
Short-term loan	'
		16	SHORT-TERM LOAN
	On September 26, 2013, Entity P entered into a short-term loan arrangement with a domestic commercial financial institution to finance its working capital. The short-term loan outstanding as of December 31, 2013 was US$1,322 with an interest rate of 7.8% per annum and a maturity term of twelve months.
	Land use rights with a net carrying amount of $1,632 (see note 11) held by Entity P was pledged as security for such short-term loan.

Longterm_Debt

Long-term Debt	12 Months Ended
	Dec. 31, 2013
Long-term Debt [Abstract]	'
Long-term debt	'
		17	LONG-TERM DEBT
	On September 5, 2013, the Company issued $600,000 in aggregate principle amount of 2.5% Convertible Senior Notes due September 15, 2018 (the “Notes”) at par. The Notes may be converted, under certain circumstances, based on an initial conversion rate of 9.0119 ADS per $1 principal amount of the Notes (which represents an initial conversion price of $110.96 per ADS).
	The notes will be our senior unsecured obligations and will rank (1) senior in right of payment to any of the Group’s existing and future indebtedness that is expressly subordinated in right of payment to the Notes, (2) equal in right of payment to any of the Group’s existing and future unsecured indebtedness that is not so subordinated, (3) junior in right of payment to any of the Group’s secured indebtedness to the extent of the value of the assets securing such indebtedness and (4) structurally junior to all existing and future indebtedness and other obligations (including trade payables and lease obligations) incurred by the Group’s subsidiaries.
	The Company has accounted for the Notes in accordance with ASC 470, as a single instrument as a long-term debt. The value of the Notes is measured by the cash received. As of December 31, 2013, $600,000 was accounted as the value of the Notes in long-term debt.
	Debt issuance costs were $12,450 and were recorded as deferred issuance costs, which were included in other noncurrent assets, are being amortized as interest expense, using the effective interest method, over the term of the Notes pursuant to ASC 835-30-35-2. The net proceeds the Company received from the issuance of the Notes were $587,850. The Company pays cash interest at an annual rate of 2.5% on the Notes, payable semi-annually in arrears on March 15 and September 15 of each year, beginning March 15, 2014. The Company recorded such interest as interest expense on an accrual basis.
	The interest expense included in the consolidated statements of operations is as follows:
			For the year ended December 31, 2013
	Interest expense at an annual rate of 2.50%		$	4,808
	Amortization of debt issuance costs			743
	Total interest expense		$	5,551
	The main terms of the Notes are summarized as follows:
	Redemption
	The Notes are not redeemable prior to the maturity date of September 15, 2018, except as described below.
		-1	Non-contingent redemption option at the option of the holder
	The holders of the Notes (the “Holders”) have an option to require the Company to repurchase for cash all or any portion of their Notes on September 15, 2016. The repurchase price will equal 100% of the principal amount of the Notes to be repurchased plus accrued and unpaid interest, if any, to, but excluding, the repurchase date.
		-2	Contingent redemption option at the option of the holder
	If a fundamental change as stipulated in the Indenture dated September 5, 2013 in connection with the Notes, occurs at any time prior to the maturity, the Holders have the option to require the Company to purchase for cash all or any portion of the Notes at a purchase price equal to 100% of the principal amount of the Notes to be purchased plus accrued and unpaid interest, if any, to, but excluding, the fundamental change purchase date.
	The Company believes that the likelihood of occurrence of events considered as a fundamental change is remote.
		-3	Redemption option at the option of the Company
	On or after September 15, 2016 (three years after the date of issuance of the Notes), the Company may redeem any or all of the Notes in cash at the redemption price, provided that the last reported sale price of the Company's ADSs for 20 or more trading days in a period of 30 consecutive trading days ending within 10 trading days immediately prior to the date of the redemption notice exceeds 130% of the applicable conversion price in effect on each such trading day. The redemption price will equal 100% of the principal amount of the notes being redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date. Any notes redeemed by the Company will be paid for in cash.
	These embedded redemption features are considered clearly and closely related to the debt host pursuant to ASC 815-15-25 and does not meet the requirements for bifurcation.
	Conversion
	The Holders may convert their Notes in integral multiples of $1 principle amount at an initial conversion rate of $110.96 per ADS, at any time prior to the maturity date of September 15, 2018. Upon conversion of the Notes, the Company will deliver shares of the Company’s ADS. The conversion rate is subject to adjustment in certain events, such as distribution of dividends and stock splits. In addition, upon a make-whole fundamental change as stipulated in the Indenture dated September 5, 2013 in connection with this Note, the Company will, under certain circumstances, increase the applicable conversion rate for a holder that elects to convert its Notes in connection with such make-whole fundamental change.
	The conversion option meets the definition of a derivative. However, bifurcation of conversion option from the Notes is not required as the conversion option is considered indexed to the entity’s own stock and classified in stockholders’ equity.
	There was no beneficial conversion feature attribute to the Notes as the set conversion price for the Notes was greater than the fair value of the ordinary share price at date of issuance.
	The Holders have the option to convert upon a fundamental change, if Holders decide to convert in connection with a fundamental change; the number of shares issuable upon conversion will be increased. The Company will have to assess for the contingent beneficial conversion feature using a measurement date upon issuance of the Notes, upon occurrence of such adjustment.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Taxes [Abstract]	'
Income Taxes	'
		18	INCOME TAXES
	Cayman
	The Company is a tax-exempted company incorporated in the Cayman Islands.
	Hong Kong
	The Company’s wholly-owned subsidiary in Hong Kong are subject to the unified tax rate of 16.5% in Hong Kong for the years ended December 31, 2011, 2012 and 2013. Under the Hong Kong tax laws, these subsidiaries are exempted from income tax on its foreign-derived income and there are no withholding taxes in Hong Kong on remittance of dividends.
	Singapore
	The Company’s wholly-owned subsidiary in Singapore, incorporated in 2013, is subject to the unified tax rate of 17% in Singapore for the year ended December 31, 2013. There are no withholding taxes in Singapore on remittance of dividends.
	Japan
	The Company’s majority-owned subsidiary in Japan, acquired in 2013, is subject to the unified tax rate of 25.5% plus 2.55% surcharge in Japan for the year ended December 31, 2013. The company also needs to pay fixed amount local income tax to the local tax authorities by monthly based on the employee headcount and capital amount. The normal withholding tax rate is 20% in Japan on remittance of dividends and could be reduced to 10% under the tax treaty between Hong Kong and Japan.
	United States of America ("USA")
	The Company’s wholly-owned subsidiary in USA, incorporated in 2013, is subject to the progressive tax rate from 15% to 39% for the federal income tax in the USA and 8.7% for the state income tax in Delaware for the year ended December 31, 2013. The normal withholding tax rate is 30% in the USA on remittance of dividends.
	PRC
	The Group's PRC entities are subject to Enterprise Income Tax ("EIT") on the taxable income in accordance with the relevant PRC income tax laws.
	The Enterprise Income Tax Law ("the New EIT Law") became effective on January 1, 2008. The New EIT Law applies a uniform 25% enterprise income tax rate to both foreign invested enterprises and domestic enterprises except for certain entities that enjoy preferential tax rates, which are lower than the statutory rates, as described below.
	Under the New EIT Law and its implementing rules, an enterprise which qualifies as a "high and new technology enterprise" ("HNTE") is entitled to a tax rate of 15%. An enterprise which qualifies as a " Software Enterprise " can enjoy an income tax exemption for two years beginning with its first profitable year and a 50% tax reduction to a rate of 12.5% for the subsequent three years. An enterprise which is approved to adopt the "deemed-profit method" can file its income tax by calculating as 2.5% of the gross revenues.
	Qizhi Software was first recognized as a HNTE by relevant PRC government authorities in 2006 and received renewals of its HNTE status in 2008 and 2011 respectively, As a consequence, Qizhi Software was entitled to a reduced EIT rate of 15% for 2011, 2012 and 2013.
	Beijing Qihu was recognized as a HNTE by relevant PRC government authorities in 2009 and received a renewal of its HNTE status in 2012, and is entitled to PRC Enterprise Income Tax of 15% tax rate for the years ended December 31, 2011, 2012 and 2013.
	Beijing Star World was recognized as a HNTE by relevant PRC government authorities starting on November 21, 2011, and is subject to 15% for the years ended December 31, 2011, 2012 and 2013, respectively.
	Tianjin Qisi is recognized as Software Enterprise by relevant PRC government authorities in March 2011 and entitled to the preferential tax treatment of "2-year exemption plus 3-year half rate" commencing from its first profit-making year for EIT purposes. For the year ended December 31, 2012 and 2013, Tianjin Qisi enjoys the 2-year tax exemption.
	Certain other PRC subsidiaries and VIEs are not subject to the unified tax rate of 25% as a result of adopting the "deemed-profit method" or the recognition as a qualified “Software Enterprise”.
	The other VIEs and VIEs’ subsidiaries are all subject to the unified tax rate of 25%.
	Uncertainties exist with respect to how the current income tax law in the PRC applies to the Group's overall operations, and more specifically, with regard to tax residency status. The New EIT Law includes a provision specifying that legal entities organized outside of the PRC will be considered residents for Chinese Income tax purposes if the place of effective management or control is within the PRC. The implementation rules to the New EIT Law provide that non-resident legal entities will be considered PRC residents if substantial and overall management and control over the manufacturing and business operations, personnel, accounting, properties, etc., occurs within the PRC. Despite the present uncertainties resulting from the limited PRC tax guidance on the issue, the Group does not believe that the legal entities organized outside of the PRC within the Group should be treated as residents for EIT law purposes. If the PRC tax authorities subsequently determine that the Company, its subsidiaries, VIEs and VIEs' subsidiaries registered outside the PRC should be deemed a resident enterprise, the Company and its subsidiaries, VIEs and VIEs' subsidiaries registered outside the PRC will be subject to the PRC income tax at a rate of 25%.
	If the Company were to be non-resident for PRC tax purpose, dividends paid to it out of profits earned after January 1, 2008 would be subject to a withholding tax. In the case of dividends paid by PRC subsidiaries, the withholding tax would be 10%. Distributions made out of pre January 1, 2008 retained earnings will not be subject to the withholding tax. The Company's PRC entities historically have not declared or paid any dividends.
	Aggregate undistributed earnings of the Company's subsidiaries, VIEs and VIEs' subsidiaries located in the PRC that are available for distribution to the Company of approximately $354,996 at December 31, 2013 are considered to be indefinitely reinvested, and accordingly, no provision has been made for the Chinese dividend withholding taxes that would be payable upon the distribution of those amounts to the Company. The Chinese tax authorities have also clarified that distributions made out of pre January 1, 2008 retained earnings will not be subject to the withholding tax.
	Detailed information about income tax of the Group's subsidiaries and VIEs is as below:
	The current and deferred portion of income tax expense included in the consolidated statements of operations is as follows:
			For the year ended December 31,
			2011			2012			2013
	Current income tax expense		$	10,724		$	12,062		$	22,382
	Deferred income tax expense (benefit)			150			(683	)		1,041
	Total income tax expense		$	10,874		$	11,379		$	23,423
	The principal components of the deferred tax assets and liabilities are as follows:
			December 31,
			2012			2013
	Current deferred tax assets:
	Accrued payroll		$	1,950		$	2,889
	Provision of allowance for doubtful accounts			125			92
	Deferred revenue-current			196			306
	Less: Valuation allowance			(140	)		(158	)
	Current deferred tax assets, net			2,131			3,129
	Noncurrent deferred tax assets:
	Deferred revenue-noncurrent			440			383
	Acquired intangible assets			175			266
	Fixed assets			-			66
	Subsidy income			130			231
	Net operating loss carry forwards			975			4,592
	Less: Valuation allowance			(975	)		(4,592	)
	Noncurrent deferred tax assets, net			745			946
	Noncurrent deferred tax liabilities:
	Acquired intangible assets			425			2,676
	Subsidy income			365			-
	Noncurrent deferred tax liabilities		$	790		$	2,676
	The Company operates through its subsidiaries and VIEs and the valuation allowance is considered on each individual subsidiary and VIE basis. The subsidiaries and VIEs registered in the PRC have total net operating loss carry forwards of $18,496 as of December 31, 2013 which will expire on various dates between December 31, 2014 and December 31, 2018.
	Reconciliation between the income tax expense computed by applying the PRC tax rate to income before income tax and the actual provision for income tax is as follows:
			For the year ended December 31,
			2011			2012			2013
	Income before income tax expense		$	25,855		$	62,695		$	124,019
	PRC statutory income tax rate			25	%		25	%		25	%
	Income tax expense at the statutory income tax rate			6,464			15,674			31,005
	Permanent differences			116			870			1,663
	Effect of different income tax calculation method required by tax bureau			(84	)		67			48
	Effect of tax exempt status in Cayman Islands			10,818			12,217			30,272
	Effect of different income tax rate in Hong Kong			(233	)		(25	)		168
Effect of tax exempt status in other jurisdictions			-			-			(31	)
Effect of income tax holiday and preferential tax rates			(7,036	)		(17,844	)		(43,460	)
Changes in valuation allowance			829			420			3,758
Income tax expense		$	10,874		$	11,379		$	23,423
Certain consolidated entities of the Group enjoy tax holidays granted by the local tax authorities. Without the tax holidays, the Group's income tax expense would have increased by $7,036, $17,844 and $43,460 for the years ended December 31, 2011, 2012 and 2013, respectively. The impact of the tax holidays on basic net income per ordinary share was an increase of $0.05, $0.10 and $0.24 for the years ended December 31, 2011, 2012 and 2013, respectively.

Ordinary_shares

Ordinary shares	12 Months Ended
	Dec. 31, 2013
Ordinary shares [Abstract]	'
Ordinary shares	'
		19	ORDINARY SHARES
	The Company's Memorandum and Articles of Association, as amended, authorizes the Company to issue 500,000,000 ordinary shares with a par value of $0.001 each as of December 31, 2011, 2012 and 2013, respectively.
	On April 4, 2011, the Company completed its IPO and a concurrent private placement upon which the Company's ordinary shares were divided into Class A ordinary shares and Class B ordinary shares. The Company newly issued 26,063,544 Class A ordinary shares, consisting of (i) 20,891,130 Class A ordinary shares offered through IPO, and (ii) 5,172,414 Class A ordinary shares issued in connection with the concurrent private placement. All of the Company's Series A, Series B and Series C shares were automatically converted into 27,024,089 Class A and 51,289,927 Class B ordinary shares.
	In September and December 2011, the Company issued 2,152,693 and 907,086 ordinary shares for future delivery to the employees and nonemployees upon exercise of share options or grant of nonvested shares, respectively.
	In March, September and December 2012, the Company issued 563,715, 2,160,951 and 2,403,180 ordinary shares for future delivery to the employees and nonemployees upon exercise of share options or grant of nonvested shares, respectively.
	In January 2012, the Company’s board of directors and shareholders approved a share repurchase program, which provided authorization to purchase up to $50 million worth of the Company's outstanding ADSs. In July 2012 and August 2012, the Company repurchased 900 and 8,796 ADSs, respectively, at a price of $14.50 and $14.31 through open-market transactions. In March 2013, the Company completed the legal process of registration for the repurchased stock.
	In June and September 2013, the Company issued 2,045,880 and 2,498,022 ordinary shares for future delivery to the employees and nonemployees upon exercise of share options or grant of nonvested shares, respectively.
	In December 2013, the Company issued 51,722 ordinary shares to a related party of the Company (see note 23(3)(i)) and 76,372 and 76,372 ordinary shares to each of the two selling shareholders , in connection with the Company’s acquisition of 51% equity interest in an overseas internet service company (see note 3 (2)).
	As of December 31, 2013, there are 134,123,218 Class A ordinary shares and 54,767,703 Class B ordinary shares outstanding, par value $0.001 per share.

Convertible_Participating_Rede

Convertible Participating Redeemable Preferred Shares	12 Months Ended
	Dec. 31, 2013
Convertible Participating Redeemable Preferred Shares [Abstract]	'
Convertible Participating Redeemable Preferred Shares	'
		20	CONVERTIBLE PARTICIPATING REDEEMABLE PREFERRED SHARES
	In January and May of 2006, the Company issued a total of 31,003,440 shares of Series A shares at Series A subscription price of $0.4999 per share for cash proceeds of $15,500. In May 2006, the Company granted a total of 1,600,320 warrants to certain Series A shareholders to purchase additional Series A shares which were exercisable into Series A shares at the Series A subscription price for $800. All of the warrants were exercised in August 2006.
	In November 2006, the Company issued 37,878,789 shares of Series B shares to Series B shareholders at Series B subscription price of $0.66 per share for cash proceeds of $25,000.
	In January 2010, the Company issued a total of 7,831,467 shares of Series C shares at Series C subscription price of $2.5538 per share for cash proceeds of $20,000.
	In April 2010, one of the shareholders of Series A shares transferred at Series C subscription price of $2.5538 per share to three investors a total of 1,691,610 Series A shares, 156,631 of which was transferred to a shareholder of both Series A shares and Series B shares. The shareholder was granted all the rights of the Series C shares for the 156,631 Series A shares.
	On April 4, 2011, Series A, Series B and Series C shares had been automatically converted into 27,024,089 Class A and 51,289,927 Class B ordinary shares after the closing of IPO.
	The main terms of Series A, Series B and Series C shares are summarized as follows:
	Rank
	The series C shares shall, with respect to (i) the payment of the liquidation payment in the event of a liquidation or a sale transaction, (ii) the payment of the dividends and (iii) all other rights and preferences, rank senior to (a) the series B shares, the series A shares and the ordinary shares; while series B shares with respect to these events rank senior to the series A shares and the ordinary shares; and the series A shares respect to these events rank senior to the ordinary shares.
	Redemption
	At any time commencing on the earlier of (a) such time as the Company's CEO is enjoined or prevented from serving as the CEO of the Company and (b) the sixth anniversary of the Series B Subscription Date, (i) if holders of at least 66 2/3% of the Series B shares approve redemption, any holder of Series B share shall be entitled to require the Company and (ii) if holders of at least 75% of the Series A shares approve redemption, any holder of Series A shares shall be entitled to require the Company, in each case by a six-month prior notice in writing to the Company to redeem, out of legally available funds, for all, but not less than all, of the Series B shares or Series A shares held by such holder, as applicable; provided the Group remain solvent and have sufficient cash for working capital required for at least one year, by reference to the annual budget approved by the Board. This redemption right set forth herein shall terminate upon closing of a qualified initial public offering ("Qualified IPO").
	At any time commencing on the fifth anniversary of the series C subscription date, if holders of at least 66 2/3% of the series C shares approve redemption, any holder of series C shares shall be entitled to require the Company, by serving a Redemption Notice on the Company, to redeem, out of legally available funds, for all, but not less than all, of the series C shares held by such holder, provided, that the Group Companies remain solvent and have sufficient cash for working capital required for at least one year by reference to the annual budget approved by the Board of Directors.
	Qualified IPO means firm commitment underwritten public offering either with total offering proceeds to the Company of at least $80,000 before deduction of the underwriting commissions and expenses or with the approval of holders of 66 2/3% or more of the then issued and outstanding preferred shares of the Company.
	Redemption Payments equal to the (i) aggregate of series C subscription price, series B subscription price or series A shares subscription price, (as adjusted for share dividends, combinations or splits or reclassification with respect to such share) plus (ii) all accumulated but unpaid dividends on the Series C shares, the Series B shares or Series A shares, as applicable, at a rate of 5% for each year the Series C shares, Series B shares or Series A shares, as applicable, remain outstanding (pro rata for a partial year).
	During the years ended December 31 2011, the Company recorded $203 as accretion of Series A shares, $313 as accretion of Series B shares and $255 as accretion of Series C shares in the consolidated statements of operations.
	Conversion
	Optional conversion-Any holder of Series A shares, Series B shares and Series C shares shall have the right, at its option, at any time and from time to time, to convert, any or all of such holder's Series A shares, Series B shares or Series C shares, as applicable, into such number of fully paid ordinary shares as is determined by dividing (i) the Series A subscription price by the then effective conversion price for the Series A shares, or (ii) the Series B subscription price by the then effective conversion price for the Series B shares, or (ii) the Series C subscription price by the then effective conversion price for the Series C shares, as applicable. The conversion price for Series A shares, Series B shares and Series C shares shall initially be equal to the Series A subscription price, the Series B subscription price and the Series C subscription price respectively, subject to adjustment for share dividend, share split or share combination, and other anti-dilution feature.
	Automatic conversion-Immediately upon closing of a Qualified IPO or approval of the holder of at least 75% of the Series A shares, each outstanding share of Series A shares shall be automatically converted, into the number of fully paid and ordinary shares in accordance with the then effective applicable conversion price.
	Immediately upon closing of a Qualified IPO, each outstanding share of Series B shares shall be automatically converted, into the number of fully paid and ordinary shares in accordance with the then effective applicable conversion price.
	Immediately upon closing of a Qualified IPO or approval of the holder of at least 75% of the Series C preferred shares, each outstanding share of Series C shares shall be automatically converted, into the number of fully paid ordinary shares in accordance with the then effective applicable conversion price.
	Dividends
	For dividend other than in ordinary shares, dividend shall be ratably paid to holders of Series C shares, Series B shares, Series A shares and Ordinary shares based on an as-if converted basis.
	For dividend in ordinary shares, holders of Series C shares, Series B shares or Series A shares shall not participate in the distribution of dividend in Ordinary Shares, but shall be entitled to adjustment to the conversion price then in effect.
	Voting rights
	The Board of Directors shall comprise a maximum of six directors, two of which shall represent Series A preferred shareholders, one of which shall represent Series B preferred shareholders. Series A, Series B and Series C shares shall be entitled to three, two and one non-voting observers to the Board of Directors, respectively. Holders of ordinary shares, voting as a single class, shall be entitled to elect a maximum of three directors.
	Liquidation preference
	Upon liquidation, out of legally available assets for shareholders, holders of Series C shares shall be paid an amount equal to Series C subscription price plus unpaid dividends if any first. Then Series B shareholders shall be paid an amount equal to Series B subscription price plus unpaid dividends if any. Then Series A shareholders shall be paid an amount equal to Series A subscription price plus unpaid dividends if any. Any remaining assets shall be distributed ratably among Series C shareholders, Series B shareholders, Series A shareholders and ordinary shareholders on an as-if converted basis. The Company has not declared any dividends for Series A shares, Series B shares, or Series C shares.

Net_Income_Per_Share

Net Income Per Share	12 Months Ended
	Dec. 31, 2013
Net Income Per Share [Abstract]	'
Net Income Per Share	'
		21	NET INCOME PER SHARE
	The following table sets forth the computation of basic and diluted net income per share for the periods indicated:
			2011		2012		2013
	Net income attributable to Qihoo 360 Technology Co. Ltd			15,603		46,746		99,652
	Accretion of Series A shares			203		-		-
	Accretion of Series B shares			313		-		-
	Accretion of Series C shares			255		-		-
	Undistributed earnings allocated to participating unvested shares (i)			1,124		2,049		3,175
	Net income attributable to Class A and Class B ordinary shareholders for computing basic net income per ordinary share			13,708		44,697		96,477
	Net income attributable to nonvested shareholders for computing basic net income per participating unvested shares (i)			1,124		2,049		3,175
	Accretion of Series A shares			203		-		-
	Net income attributable to Series A shareholders for computing basic net income per Series A share			203		-		-
	Accretion of Series B shares			313		-		-
	Net income attributable to Series B shareholders for computing basic net income per Series B share			313		-		-
	Accretion of Series C shares			255		-		-
	Net income attributable to Series C shareholders for computing basic net income per Series C share			255		-		-
	Weighted average ordinary shares outstanding used in computing basic net income per Class A and Class B ordinary share			137,775,752		168,709,221		174,727,288
	Weighted average shares used in calculating net income per participating unvested share-basic			11,292,535		7,733,645		5,749,393
	Weighted average shares outstanding used in computing basic net income per Series A share			8,356,247		-		-
	Weighted average shares outstanding used in computing basic net income per Series B share			9,755,085		-		-
	Weighted average shares outstanding used in computing basic net income per Series C share			2,057,209		-		-
	Effect of dilutive securities:
	Plus incremental weighted average ordinary shares from assumed exercise of stock options and nonvested shares using the treasury stock method (ii)			4,345,724		7,180,369		12,560,169
	Plus incremental weighted average ordinary shares from assumed conversion of preferred share using treasury stock method			19,578,504		-		-
	Weighted average ordinary shares outstanding used in computing diluted net income per Class A and Class B ordinary share (i)			172,992,515		183,623,235		193,036,850
	Net income per Class A and Class B ordinary share-basic			0.1		0.26		0.55
	Net income per participating unvested share-basic			0.1		0.26		0.55
	Net income per Series A share-basic			0.02		NA		NA
	Net income per Series B share-basic			0.03		NA		NA
	Net income per Series C share-basic			0.12		NA		NA
	Net income per Class A and Class B ordinary share-diluted			0.09		0.25		0.52
		(i)	The net income attributable to Qihoo 360 Technology Co. Ltd. was allocated among Class A and Class B ordinary shares (see Note 19), preferred shares (See Note 20) and certain nonvested shares (see Note 22) pro rata on the basis of their right to participate in dividends.
		(ii)	The calculation of the weighted average number of Class A and Class B ordinary shares for the purpose of diluted net income per share has considered the effect of certain potentially dilutive securities. For the year ended December 31, 2011, the incremental weighted average number of 19,578,504 and 4,345,724 ordinary shares from the assumed conversion of Series A, B and C preferred shares, and the exercise of share options and nonvested shares using the treasure stock method, respectively, has been included in the dilutive securities. For the years ended December 31, 2012 and 2013, the incremental weighted average number of 7,180,369 and 12,560,169 ordinary shares from the assumed exercise of share options and nonvested shares using the treasury stock method, respectively, has been included in the dilutive securities.
	For the year 2011, 2012 and 2013, 2,552,844, 4,990,513 and 533,054 share options were excluded as their effect was anti-dilutive, respectively.
	For the year 2013, 2,578,779 ordinary shares resulting from the assumed conversions of Convertible Senior Notes were excluded from the calculation of diluted net income per share as their effect was anti-dilutive.

Sharebased_Compensation

Share-based Compensation	12 Months Ended
	Dec. 31, 2013
Share-based Compensation [Abstract]	'
Share-based Compensation	'
		22	SHARE-BASED COMPENSATION
	Share options
	On January 25, 2006, the Company adopted the 2006 Employee Share Option Plan (the "2006 Plan") for the granting of share options to employees and nonemployees to reward them for services to the Company and to provide incentives for future service. The share options expire ten years from the date of grant.
	On April 1, 2011, the Company adopted the 2011 Employee Share Incentive Plan (the "2011 Plan") for the granting of share options and nonvested shares (see note 22) to employees and nonemployees to reward them for services to the Company and to provide incentives for future service. The share options expire ten years from the date of grant.
	Option to employees and directors
	On January 1, 2011, February 14, 2011, March 3, 2011, July 1, 2011 and October 1, 2011, the Company granted 3,726,200, 700,000, 684,500, 2,689,200 and 375,000 share options to employees at an exercise price of $5.2, $5.2, $6.0, $12.94 and $10.89 per share, respectively.
	On July 1, 2011, the Company granted 40,000 share options to two directors at an exercise price of $9.67 per share.
	On January 20, 2012, February 10, 2012, April 15, 2012, July 15, 2012 and October 15, 2012, the Company granted 1,834,500, 935,000, 171,500, 417,500 and 761,500 share options to employees at an exercise price of $10.67, $11.35, $14.52, $10.95 and $14.67 per share, respectively.
	On January 15, 2013, April 15, 2013, July 15, 2013 and Oct 15, 2013, the Company granted 681,500, 406,000, 188,000 and 145,500 share options to employees at an exercise price of $21.09, $20.11, $35.27 and $55.38 per share, respectively.
	Option to nonemployees
	On January 1 and March 3, 2011, the Company granted 60,000 and 20,000 share options to nonemployees for consulting and investment advisory services of three or four years at an exercise price of $5.2 and $6.0 per share, respectively.
	On March 1, 2012, July 15, 2012, July 15, 2012 and October 15, 2012, the Company granted 33,000, 10,000, 40,000 and 10,000 share options to nonemployees for consulting and investment advisory services of four years at an exercise price of $14.09, $10.95, $10.67 and $14.67 per share, respectively.
	On January 15, 2013, January 16, 2013, the Company granted 20,000 and 80,000 share options to nonemployees for consulting and investment advisory services of four years at an exercise price of $21.09 and $12.94 per share, respectively.
	Option exercise
	The option shall be exercisable by giving notice in writing to the Company stating that the option is exercised and the number of shares in respect of which it is exercised. Any such notice must be accompanied by a remittance for the full amount of the exercise price for the shares in respect of which the notice is given.
	Vesting of options
	Under the 2006 Plan, the option will vest when the service conditions are met. In addition, according with the 2006 Plan, one of the exit events, described in "Termination of Option" below, shall happen. In accordance with the vesting schedules set out in the 2006 Plan, unless otherwise determined by the CEO of the Company, 1/4 of the options granted will be vested on each anniversary from the date of grant subject to the occurrence of one of the exit events.
	Under the 2011 Plan, the Plan administrator (compensation committee) has the authority to determine the schedule for vesting. The vast majority of share options granted under the 2011 Plan shall vest (i) 20 per cent of the aggregate number of options 12 months after the start of vesting period; (ii) 20 per cent of the aggregate number of options 24 months after the start of vesting period; (iii) 30 per cent of the aggregate number of options 36 months after the start of vesting period; and (iv) 30 per cent of the aggregate number of options 48 months after the start of vesting period.
	Termination of option
	Both under the 2006 and the 2011 Plan, the option may not be exercised until vested. Once vested, the option may be exercised in whole or any part, at any time. However, an option will be forfeited, if the grantee ceases to be an employee.
	Furthermore, in accordance with the 2006 Plan, an option will be forfeited, if the grantee ceases to be an employee prior to an exit, then (i) the portion of the option which has been otherwise vested and not exercised, and (ii) the portion of the options which has not been vested, will automatically lapse and expire.
	Exit means (i) a listing, (ii) a sale of all or substantially all of the issued share capital of the Company, (iii) a sale by the Company of all or substantially all of its assets, (iv) the passing of an effective resolution or the making of an order of a competent court for the winding up of the Company.
	Based on the terms above, the options will not actually vest until one of the exit events happens and the service conditions are met.
	Under the 2011 Plan, the Plan administrator (compensation committee) has the authority to terminate the option shall certain events happen.
	The fair value of the options granted is estimated on the date of grant using the Black-Scholes or Binomial-Model option-pricing model with the following assumptions used.
			Year ended December 31,
			2012			2013
	Risk-free interest rate			2.83% - 3.35%			3.40% - 4.02%
	Expected life (years)			6.35			6.35
	Volatility			46.98% - 74%			46.04% - 46.68%
	Dividend yield			-			-
		-1	Volatility
	The volatility of the underlying ordinary shares during the life of the options was estimated based on the historical share price volatility of comparable companies over a period comparable to the expected term of the options.
		-2	Risk-free interest rate
	Risk-free interest rate was estimated based on the yield to maturity of China international government bonds with a maturity period close to the expected term of the options.
		-3	Expected term
	For the options granted to employees, as the Group did not have sufficient historical share option exercise experience, it estimated the expected term average based on a consideration of factors including contractual term and vesting period.
		-4	Dividend yield
	The dividend yield was estimated by the Group based on its expected dividend policy over the expected term of the options.
		-5	Exercise price
	The exercise price shall be determined by the Compensation Committee which may be a fixed or variable price related to the closing sales price of the shares as quoted on the principal exchange or system.
		-6	Fair value of underlying ordinary shares
	The fair value of the ordinary shares is determined as the closing sales price of the shares as quoted on the principal exchange or system.
	The following table summarizes information regarding the share options granted:
						Fair value per				Intrinsic value
						ordinary share		Exercise price		per option
	Grant date		Options granted			at the grant date		per option		at the grant date
	1-Jan-10			110,000		$	1.8	$	2.2		-
	1-Jul-10			5,039,000		$	2.58	$	2.8		-
	1-Jan-11			3,786,200		$	5.01	$	5.2		-
	14-Feb-11			700,000		$	6.6	$	5.2	$	981
	3-Mar-11			704,500		$	7.21	$	6	$	849
	1-Jul-11			2,689,200		$	14.09	$	12.94	$	3,102
	1-Jul-11			40,000		$	14.09	$	9.67	$	177
	1-Oct-11			375,000		$	10.89	$	10.89		-
	20-Jan-12			1,834,500		$	11.67	$	10.67	$	1,835
	10-Feb-12			935,000		$	11.17	$	11.35		-
	1-Mar-12			33,000		$	14	$	14.09		-
	15-Apr-12			171,500		$	14.52	$	14.52		-
	15-Jul-12			427,500		$	10.95	$	10.95		-
	15-Jul-12			40,000		$	10.95	$	10.67	$	11
	15-Oct-12			771,500		$	14.73	$	14.67	$	51
	15-Jan-13			701,500		$	20.55	$	21.09		-
16-Jan-13			80,000		$	20.33	$	12.94	$	591
15-Apr-13			406,000		$	19.92	$	20.11		-
15-Jul-13			188,000		$	36.85	$	35.27	$	298
15-Oct-13			145,500		$	57.03	$	55.38	$	240
Total			19,177,900
The following table summarizes the option activity for the year ended December 31, 2013:
					Weighted average
					exercise price
		Number of options			per option
Outstanding at December 31, 2012			15,148,014			7.2
Granted			1,521,000			25.4
Exercised			(3,982,385	)		4.8
Expired			(37,076	)		11.6
Forfeited			(1,167,040	)		11.3
Outstanding at December 31, 2013			11,482,513		$	10
Vested and exercisable at December 31, 2013			3,840,705		$	5.5
Vested and expect to vest at December 31, 2013			17,152,097		$	8.3
The following table summarizes information with respect to share options outstanding as of December 31, 2013:
		Options outstanding									Options exercisable
					Weighted				Aggregate						Aggregate
					average				intrinsic						intrinsic
					remaining		Exercise		value as of				Exercise		value as of
		Number			contractual		price		December 31,		Number		price per		December 31,
		outstanding			term		per option		2013		exercisable		option		2013
30-Jun-09			367,337			5.5 years	$	1.5	$	19,542		371,710	$	1.5	$	19,775
1-Jan-10			50,854			6.0 years	$	2.2		2,670		33,354	$	2.2		1,751
1-Jul-10			1,974,966			6.5 years	$	2.8		102,501		1,596,466	$	2.8		82,857
1-Jan-11			2,422,833			7.0 years	$	5.2		119,930		795,683	$	5.2		39,386
14-Feb-11			421,000			7.1 years	$	5.2		20,840		71,000	$	5.2		3,515
3-Mar-11			277,659			7.2 years	$	6		13,522		80,409	$	6		3,916
1-Jul-11			1,434,439			7.5 years	$	12.94		59,902		408,556	$	12.94		17,061
1-Jul-11			40,000			7.5 years	$	9.67		1,801		16,000	$	9.67		721
1-Oct-11			160,440			7.7 years	$	10.89		7,028		50,440	$	10.89		2,210
January 20,2012			1,007,053			8.0 years	$	10.67		44,344		98,653	$	10.67		4,344
10-Feb-12			698,002			8.1 years	$	11.35		30,261		122,003	$	11.35		5,289
1-Mar-12			26,400			8.2 years	$	14.09		1,072		-	$	14.09		-
15-Apr-12			110,057			8.3 years	$	14.52		4,422		14,057	$	14.52		565
15-Jul-12			315,219			8.5 years	$	10.95		13,790		49,220	$	10.95		2,153
15-Jul-12			40,000			8.5 years	$	10.67		1,761		8,000	$	10.67		352
15-Oct-12			665,754			8.8 years	$	14.67		26,652		125,154	$	14.67		5,010
15-Jan-13			693,500			9.0 years	$	21.09		23,311		-	$	21.09		-
16-Jan-13			80,000			9.0 years	$	12.94		3,341		-	$	12.94		-
15-Apr-13			366,000			9.3 years	$	20.11		12,659		-	$	20.11		-
15-Jul-13			186,000			9.5 years	$	35.27		3,615		-	$	35.27		-
15-Oct-13			145,000			9.8 years	$	55.38		-		-	$	55.38		-
Total			11,482,513						$	512,964		3,840,705			$	188,905
The weighted-average grant-date fair value per option granted for the years ended December 31, 2011, 2012 and 2013 was $4.36, $6.77 and $13.19, respectively.
The total intrinsic value of options exercised for the years ended December 31, 2011, 2012 and 2013 was $311, $19,486 and $138,364, respectively. The intrinsic value is calculated as the difference between the market value on the date of exercise and the exercise price of the shares.
Under the 2006 Plan, the options would not vest until both the service and performance condition, i.e., one of the exit events happens. Therefore, the Group did not record any compensation expenses in the consolidated statements of operation for share options granted to employees prior to the completion of IPO which is one of the exit events. Upon the completion of IPO in 2011, there were 229,988 share options became vested in accordance with the vesting term under 2006 Plan, and accordingly, $21,229 share based compensation expense were recorded in connection with the vesting of such share options and the remeasurement of share options granted to the nonemployees that the measurement date is not fixed.
The Group recognized $34,504, $26,997 and $21,921 share-based compensation expense for the years ended December 31, 2011, 2012 and 2013, respectively.
As of December 31, 2013, there was $33,509 unrecognized share-based compensation expense relating to share options. The expense is expected to be recognized over a weighted-average remaining vesting period of 1.53 years.
Nonvested shares
On January 19, 2006, the Company's shareholder, Young Vision, the Series A shareholder and certain other parties entered into the Share Incentive Agreement, pursuant to which, Young Vision allocated a total of 18,086,101 ordinary shares of the Company to an equity incentive pool designed to award employees and consultants of the Group in accordance with the Employee Share Vesting Scheme (the "2006 Share Plan"), of which 9,951,000 shares were granted before January 1, 2008. In addition, in January 2010, the Company issued 3,517,544 nonvested shares in connection with certain 2009 acquisitions.
In February 2011, Young Vision transferred 11,826,000 and 5,550,654 ordinary shares in the equity incentive pool to Sino Honor Limited ("Sino Honor") and Strengthen Goal Limited ("Strengthen Goal"), which are also companies owned by the Company's director and employee, respectively.
The nonvested shares granted or vested in accordance with the 2006 Share Plan will, be held by Young Vision, Sino Honor and Strengthen Goal, and all rights (including without limitation, the voting rights and the right to receive the share certificates) attached to such shares will be exercised by Young Vision, Sino Honor and Strengthen Goal at their sole and absolute discretion, except that the grantee shall have the right to all the monetary benefits deriving from the shares vested when the shares are disposed of in accordance with the 2006 Share Plan. Since the unvested nonvested shares are entitled to the same rights (including nonforfeitable dividend rights) and obligations as ordinary shares, these shares are considered participating securities.
The nonvested shares granted under the 2006 Share Plan shall vest (i) 15 per cent of the aggregate number of shares 12 months after the start of vesting period; (ii) 20 per cent of the aggregate number of shares 24 months after the start of vesting period; (iii) 30 per cent of the aggregate number of shares so granted 36 months after the start of vesting period; and (iv) 35 per cent of the aggregate number of Shares 48 months after the start of vesting period.
However, all nonvested shares to any grantee shall also be subject to the Company's rights to repurchase at an aggregate repurchase price of RMB1.00, if the grantee terminated his/her employment with the Group: (a) in all, on or before the second anniversary of the start of vesting period; (b) 50% of otherwise vested nonvested shares, after the second anniversary but before the fourth anniversary of the start of vesting period; or (c) no shares, after the fourth anniversary of the start of vesting period.
Under the 2011 Plan, the nonvested shares granted shall vest based on service, or any other criteria selected by the Compensation Committee. If the grantee terminated his/her service ("Termination of Service") with the Group, the Group shall have the right to repurchase the unvested nonvested shares.
Termination of Service means (i) As to a consultant, the time when she/he is terminated for any reason, (ii) As to a non-employee director, the time when non-employee director ceases to be a director for any reason, (iii) As to an employee, the time when the employee-employer relationship is terminated for any reason. However, all terminations shall exclude simultaneously commences or remains in employment or service with the Company, any subsidiaries or VIEs and VIEs' subsidiaries in others way.
The following table summarizes information regarding the nonvested shares granted:
					Weighted average
					fair value per
		Number of			nonvested share
		nonvested shares			at the grant date(i)
Outstanding at January 1, 2011			11,133,594
Granted			3,255,976		$	7.76
Vested			(5,824,709	)		1.28
Forfeited			(380,610	)		1.58
Outstanding at December 31, 2011			8,184,251
Granted			4,845,877			12.03
Vested			(3,136,471	)		2.32
Forfeited			(1,121,419	)		7.34
Outstanding at December 31, 2012			8,772,238		$	8.38
Granted			5,148,971			32.02
Vested			(3,038,327	)		23.55
Forfeited			(812,088	)		13.92
Outstanding at December 31, 2013			10,070,794		$	15.44
Vested and to be transferred to grantees at December 31, 2013			18,416,568
Vested and expect to vest at December 31, 2013			27,188,805
	(i)	The fair value of the underlying ordinary shares is the same as the fair value of the nonvested shares when calculating the weighted average fair value per nonvested share at the grant date.
Included in the nonvested shares granted during 2013, there were 1,000,000 nonvested shares granted to the two co-founders of the Company to reward them for their outstanding performance in the past years. These nonvested shares vested immediately and the Company recognized $57,027 share based compensation expense as a result of such grant for the year ended December 31, 2013.
The fair value of the nonvested shares was determined by the closing sales price of the shares as quoted on the principal exchange or system. The total fair value of the nonvested shares vested for the years ended December 31, 2011, 2012 and 2013 was $7,671, $8,361 and $70,980, respectively.
The Group recognized $13,485, $23,608 and $99,166 share based compensation expense for the years ended December 31, 2011, 2012 and 2013 respectively.
As of December 31, 2013, total unrecognized compensation expense relating to the nonvested shares was $73,325. The expense is expected to be recognized over a weighted average period of 2.67 years using the graded vesting attribution method.

Related_party_balances_and_tra

Related party balances and transactions	12 Months Ended
	Dec. 31, 2013
Related party balances and transactions [Abstract]	'
Related party balances and transactions	'
		23	RELATED PARTY BALANCES AND TRANSACTIONS
	The Group's related parties and the relationship with the Group are as follows:
	Name of the related party		Relationship with the Group
	Related party F		The Group's cost method investee
	Related party G		Noncontrolling interest shareholder of one of the Group's subsidiaries
	Related party H		The Group's equity method investee
	Related party I		The Group's equity method investee
	Related party J		The Group's equity method investee
	Related party K		The Group's equity method investee
	Related party L		The Group's equity method investee
	Related party M		The Group's equity method investee
	Related party N		Chairman and Chief Executive Officer of the Company
	Related party O		Noncontrolling interest shareholder of one of the Group's subsidiaries
	Details of related party balances and main transactions as of December 31, 2011, 2012 and 2013 are as follows:
		-1	Amount due from related parties
			December 31,
			2012				2013
	Related party H (i)		$	-			$	1,542
	Related party I (i)		$	-			$	496
	Related party J (ii)		$	-			$	627
	Related party L (iii)		$	-			$	206
			$	-			$	2,871
		(i)	The balances represent additional capital injection to equity method investees. As of December 31, 2013, the payments were made but the legal process has not been completed.
		(ii)	The balance mainly represents the receivable for the online marketing service provided to related party J.
		(iii)	It represents the unsecured interest-free bridge loans provided to related party L.
		-2	Amount due to related parties
			December 31,
			2012				2013
	Related party G (iii)		$	148			$	-
	Related party K (i)		$	-			$	83
	Related party J (ii)		$	-			$	431
	Related party M (ii)		$	-			$	3
			$	148			$	517
		(i)	It represents the additional capital injection to be paid to related party K.
		(ii)	The balances represent the unpaid revenue sharing related to game operation.
		(iii)	It represents the pre-operating expenses paid by related party G on behalf of one of the Group's subsidiary, which has been settled in February 2013. The Group deconsolidated this subsidiary in September 2013.
		-3	Main transactions with related parties
					For the year ended December 31,
	Nature		Company name		2011				2012		2013
	Marketing promotion received from		Related party F		$	56			$	-	$	-
	Online marketing promotion service fees received from		Related party J		$	-			$	-	$	387
	Revenue sharing related to game operation paid to		Related party J		$	-			$	-	$	199
	Revenue sharing related to game operation paid to		Related party M		$	-			$	-	$	266
	Purchase of shares from (i)		Related party N		$	-			$	-	$	1,989
	Disposal equity interest of a subsidiary (ii)		Related party O		$	-			$	4,207	$	-
		(i)	In July 2013, the Group acquired 51% equity interest of an overseas internet service company from three selling shareholders, one of which is related party N. The Company settled the consideration of $1,989 for 28.53% equity interest from related party N by issuance of 51,722 ordinary shares, equivalent to 34,481 ADSs, based upon the closing price of the Company's ADSs at the acquisition date. Please refer to note 3 (2) for detail of the transaction.
		(ii)	On January 10, 2012, the Group entered into a termination agreement with related party U. Pursuant to the termination agreement, the Group agreed to dispose its 53.5% equity interest in one of its former subsidiaries to related party O.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies [Abstract]	'
Commitments and Contingencies	'
		24	COMMITMENTS AND CONTINGENCIES
		-1	Capital commitments
	The Group's capital commitments relate primarily to commitments on building and land use rights for the new office in Chaoyang District, Beijing, China. Total capital commitments contracted but not yet reflected in the consolidated financial statements amounted to $84 million as of December 31, 2013. The Group will fulfill the capital commitments in 2014.
		-2	Operating commitments
	The Group has future rental commitments related to facilities and offices under non-cancelable operating lease agreements, advertising agreements and fees commitment related to obtain exclusive rights of operating games on the Group's platform.
	Future minimum payments under those commitments as of December 31, 2013 were as follows:
	2014		$	8,712
	2015			3,218
	2016			1,591
	2017			743
	2018			702
			$	14,966
	Rental expenses under operating leases for 2011, 2012 and 2013 were $4,261, $5,967 and $5,057, respectively.
		-3	Other commitments
	The Group has future commitment relates to interest payable in connection with the issuance of Notes (see Note 17).
	Assuming all debt was held to maturity, future maximum payments under those commitments as of December 31, 2013 were as follows:
	2014		$	15,000
	2015			15,000
	2016			15,000
	2017			15,000
	2018			10,583
			$	70,583
		-4	Contingencies
	In October 2010, Tencent Technology (Shenzhen) Company Ltd. and Shenzhen Tencent Computer Systems Company Limited, or Tencent, brought an unfair competitive practices claim against the Group in the Chaoyang District People's Court of Beijing, alleging that the Group misled users with statements that Tencent's QQ instant messaging program invades users' privacy and seeking retraction of the statements and RMB4.0 million in damages. In September 2011, the court ruled that the Group's actions constituted unfair competition and awarded RMB0.4 million ($63,553) as damages to Tencent. In November 2010, the Group brought a defamation claim against Tencent in the Xicheng District People's Court of Beijing, alleging that Tencent made defamatory statements on its website against the Group and seeking retraction of the statements and RMB1.0 in nominal damages. In March 2012, the Group increased its sought damages to RMB 1.0 million ($0.2 million). This case is currently pending.
	In June 2011, Tencent brought an unfair competitive practices claim against the Group in the Higher People's Court of Guangdong province, alleging that the Group's 360 QQ Bodyguard program interferes with users' proper usage of Tencent's QQ instant messaging program and seeking $19.8 million (RMB125.0 million) in damages, cessation of the unfair competitive practices and public apology. In April 2013, the first instance judgment was issued by the Higher People’s Court of Guangdong Province, which ruled in Tencent’s favor. The Group was ordered to pay Tencent a sum of $0.8 million (RMB 5 million) and accrued as liabilities as of December 31, 2013. The Group appealed in May 2013 and the court of second instance upheld the judgment of the court of first instance in February 2014.
	In November 2011, the Group brought a claim for abuse of dominant market position against Tencent in the Higher's People's Court of Guangdong province, alleging that Tencent engaged in monopolistic activities such as restricting users of its QQ instant messaging program from using the Group's products and bundling its security programs with the QQ instant messaging program and seeking $23.8 million (RMB150.0 million) in damages, cessation of the monopolistic activities and public apology. This claim was rejected by the court in the first instance judgment. The Group subsequently submitted its appeal in April 2013 and the court of second instance heard the case in November 2013. This case is currently pending.
	In April 2012, two affiliates of Baidu brought an unfair competitive practices and copyright infringement claim against the Group in the First Intermediate People's Court of Beijing, alleging that 360 Safe Guard modified the results page of Baidu's search engine that 360 Browser bundled Baidu personal start-up pages and the unauthorized use of Baidu's trademark and seeking RMB10 million in damages. In April of 2013, the first instance judgment was issued by the First Intermediate People's Court of Beijing, which ruled in Baidu's favor. The Group are ordered to pay Baidu a sum of RMB450,000 and have accrued this as liabilities as of December 31, 2013. The Group appealed in May 2013 and the court of second instance upheld the judgment of the court of first instance in December 2013.
	In April 2012, the Group brought a claim against Kingsoft and Beike Wangji (Beijing) Security Technology Company Limited, or Beike, for an unfair competitive advertisement for the incident relating to Apple banning the Group's products from the Apple App Store. In November of 2012, the first instance judgment was made by Beijing Haidian Court, which ruled in the Group's favor. Kingsoft and Beike appealed in December 2012 and the court of second instance upheld the judgment of the court of first instance. In May 2012, Kingsoft brought an unfair competition claim against the Group for unfair competition, and the court of first instance entered a judgment in the Group's favor in December 2012. Kingsoft appealed in December 2012 and the court of second instance upheld the judgment of the court of first instance.
	In October 2012, two affiliates of Baidu brought an unfair competitive practices and copyright infringement claim against the Group in the First Intermediate People's Court of Beijing, alleging that the Group breached the Robots Exclusion Protocol to access Baidu's content without authorization and seeking RMB100.0 million in damages. The court heard the case in October 2013 and this case is currently pending.
	In February 2013, the Group brought a defamation claim against Shanghai Jingwen Culture Communication Co., Ltd., or Shanghai Jingwen, in the Xuhui District People's Court of Shanghai, alleging that Shanghai Jingwen published and distributed a series of false articles and reports against the Group on its website and electronic newspapers by maliciously accusing the level of safety and security of its products. The Group sought retraction of the defamatory statements, an apology from Shanghai Jingwen and RMB50 million in damages. This case is currently pending.
	In September 2013, the Group brought an unfair competitive practices claim against two affiliates of Sogou Inc., or Sogou, in the Second Intermediate People’s Court of Beijing, alleging that Sogou made defamatory statements on its public Weibo account and through online videos against the Group and seeking cessation of the unfair competitive practices, a retraction of the defamatory statements and RMB50.0 million in damages. This case is currently pending.
	In October 2013, two affiliates of Sogou brought an unfair competitive practices claim against the Group in the Intermediate People’s Court of Xi’an, alleging that the Group used its software to change user default settings without their permission, including setting their default browser as 360 Safe Browser, which interfered with their use of Sogou’s browser. The claim sought cessation of the unfair competitive practices and RMB45.5 million in damages. This case is currently pending.
	In October 2013, two affiliates of Sogou brought an unfair competitive practices claim against the Group in the Second Intermediate People’s Court of Beijing, alleging that the Group’s 360 Safe Guard issued blocking notifications for other types of software, which negatively impacted their ability to run their business. The claim sought cessation of the unfair competitive practices and RMB50.0 million in damages. This case is currently pending.
	In November 2013, the Group brought an unfair competitive practices claim against two affiliates of Sogou in the Second Intermediate People’s Court of Beijing, alleging that Sogou made defamatory statements on its public Weibo account against the Group which caused severe reputational damage to the Group and seeking cessation of the unfair competitive practices, a retraction of the defamatory statements and RMB10.1 million in damages. This case is currently pending.
	Other than the aforementioned lawsuits, the Group is also a party to several legal proceedings or claims in China that the Group believes are immaterial.
	Based on information currently available, the Group cannot reasonably estimate the loss that is reasonably possible at this stage except for two of the above cases. Therefore, no accrual for contingency loss was recognized in the consolidated financial statements as of December 31, 2011 and 2012 and US$0.9 million was recognized in the consolidated financial statements as of December 31, 2013.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2013
Fair Value Measurements [Abstract]	'
Fair Value Measurements	'
		25	FAIR VALUE MEASUREMENTS
	Measured on recurring basis
	The Group measured its financial assets including cash equivalents, trading securities and available-for-sale investment at fair value on a recurring basis as of December 31, 2012 and 2013.
	Cash equivalents included term deposits that can be withdrawn at any time and are stated at fair value. Trading securities included corporate equity securities that are traded publicly in the open market. The Group classified such financial assets as investments with Level 1 of the fair value hierarchy because they are valued based on the quoted market price in an active market.
	The Group did not have Level 2 investments as of December 31, 2012 and 2013.
	The following table shows the fair value of the Group's financial assets and liabilities measured at recurring basis as of December 31, 2012 and 2013:
		As of December 31, 2012								As of December 31, 2013
		Fair Value Measurements at the Reporting Date Using								Fair Value Measurements at the Reporting Date Using
		Quoted prices in		Significant						Quoted prices in		Significant
		active markets		other		Significant				active markets		other		Significant
		for identical		observable		unobservable				for identical		observable		unobservable
		instruments		inputs		inputs		Total		instruments		inputs		inputs		Total
		(level 1)		(level 2)		(level 3)		balance		(level 1)		(level 2)		(level 3)		balance
	Cash equivalents-term deposits	$	153,805	$	-	$	-	$	153,805	$	683,994	$	-	$	-	$	683,994
	Trading securities		179		-		-		179		253		-		-		253
	Total	$	153,984	$	-	$	-	$	153,984	$	684,247	$	-	$	-	$	684,247
	Measured on nonrecurring basis
	The Group measured the fair value of the purchased intangible assets using the "cost," "income approach-excess earnings" and "with & without" valuation method.
	Long-term investments, goodwill and other intangible assets are measured at fair value on a nonrecurring basis and they are recorded at fair value only when impairment is recognized.
	The Group measured the fair value of long term investments and acquired intangible assets using income approach-discounted cash flow method based on which to recognize the impairment loss in 2013. These assets are considered as Level 3 assets because the Group used unobservable inputs to determine their fair values (see note 9 (iii) and (iv) for long term investments and note 12 for acquired intangible assets).

Segments_and_geographic_inform

Segments and geographic information	12 Months Ended
	Dec. 31, 2013
Segments and geographic information [Abstract]	'
Segments and geographic information	'
		26	SEGMENT AND GEOGRAPHIC INFORMATION
	The Group's chief operating decision maker has been identified as the Chief Executive Officer ("CEO"), who reviews consolidated results when making decisions about allocating resources and assessing performance of the Group. The Group has one operating segment. The Group's revenue and net income are substantially derived from internet service which mainly includes online advertising and internet value-added services. The table below is only presented at the revenue level with no allocations of direct or indirect costs. The Group mainly operates in the PRC and majority of the Group's long-lived assets are located and services are provided in the PRC.
	Components of revenues are presented in the following table:
			For the year ended December 31,
			2011		2012		2013
	Internet services
	Online advertising		$	123,048	$	221,488	$	417,133
	Internet value-added services			43,567		103,316		252,684
	Other services			346		4,078		1,271
	Sales of third party anti-virus software			890		150		-
	Total		$	167,851	$	329,032	$	671,088

Mainland_China_Contribution_Pl

Mainland China Contribution Plan and Profit Appropriation	12 Months Ended
	Dec. 31, 2013
Contribution Plan and Profit Appropriation [Abstract]	'
Contribution Plan and Profit Appropriation	'
		27	MAINLAND CHINA CONTRIBUTION PLAN AND PROFIT APPROPRIATION
	Full time employees of the Group in the mainland China participate in a government-mandated multi-employer defined contribution plan pursuant to which certain pension benefits, medical care, unemployment insurance, employee housing fund and other welfare benefits are provided to employees. Chinese labor regulations require the Group to accrue for these benefits based on certain percentages of the employees' salaries. The total provisions for such employee benefits were $7,017, $18,125 and $31,441 for the years ended December 31, 2011, 2012 and 2013, respectively.
	PRC legal restrictions permit payments of dividends by the Group's PRC entities only out of their retained earnings, if any, determined in accordance with PRC regulations. Prior to payment of dividends, pursuant to the laws applicable to the PRC Domestic Enterprises and PRC Foreign Investment Enterprises, the PRC entities must make appropriations from after-tax profit to non-distributable statutory reserve funds as determined by the Board of Directors of the Group. These reserve funds include the (1) general reserve, (2) enterprise expansion fund and (3) staff bonus and welfare fund. Subject to certain cumulative limits, the general reserve fund requires annual appropriations of not less than 10% of after-tax profit (as determined under accounting principles and financial regulations applicable to PRC enterprises at each year-end); the other two funds are at the Group's discretion. These reserve funds can only be used for specific purposes and are not distributable as cash dividends. The Group has made appropriation to these statutory reserve funds of $5,503, $10,408 and $12,074 for the years ended December 31, 2011, 2012 and 2013, respectively.

Restricted_Net_Assets

Restricted Net Assets	12 Months Ended
	Dec. 31, 2013
Restricted Net Assets [Abstract]	'
Restricted Net Assets	'
		28	RESTRICTED NET ASSETS
	Relevant PRC statutory laws and regulations permit the payment of dividends by the Group's PRC subsidiaries, VIEs and VIEs' subsidiaries only out of their retained earnings, if any, as determined in accordance with PRC accounting standards and regulations. In addition, PRC laws and regulations require that annual appropriations of 10% of after-tax income be set aside as a reserve prior to the payment of dividends. As a result of these PRC laws and regulations, the Group's PRC subsidiaries, VIEs and VIEs' subsidiaries are restricted in their ability to transfer a portion of their net assets to the Company either in the form of dividends, loans or advances. The balance of restricted net assets was $156,762 and $261,895, of which $68,067 and $89,243 was attributed to the paid in capital and statutory reserves of the VIEs and VIEs' subsidiaries and $88,695, and $172,652 was attributed to the paid in capital and statutory reserves of the Company's PRC subsidiaries, as of December 31, 2012 and 2013, respectively. The PRC subsidiaries' accumulated profits may be distributed as dividends to the Company without the consent of a third party. The VIEs' revenues and accumulated profits may be transferred to Qizhi Software through contractual arrangements without the consent of a third party.

Subsequent_Events

Subsequent Events	12 Months Ended
	Dec. 31, 2013
Subsequent Events [Abstract]	'
Subsequent Events	'
		29	SUBSEQUENT EVENTS
	In January 2014, the Group entered into a Share Purchase Agreement with the third parties to acquire 100% equity interest of a game platform operating company with total consideration $67.4 million.

Additional_Information_Financi

Additional Information - Financial Statement Schedule I Condensed Financial Information of Parent Company	12 Months Ended
	Dec. 31, 2013
Additional Information - Financial Statement Schedule I Condensed Financial Information of Parent Company [Abstract]	'
Condensed Financial Information of Parent Company	'
		December 31,
		2012			2013
	ASSETS
	Current assets:
	Cash and cash equivalents	$	220,236		$	695,515
	Restricted cash		300			300
	Trading securities		179			253
	Prepaid expenses and other current assets		8,416			3,206
	Amounts due from subsidiaries and VIEs		29,805			167,395
	Deferred tax assets - current		195			306
	Total current assets		259,131			866,975
	Acquired intangible assets, net		3,923			2,449
	Investments in subsidiaries and VIEs		219,380			449,893
	Cost method investment		1,379			17,139
	Other non-current assets		-			11,707
	Deferred tax assets - noncurrent		440			383
	TOTAL ASSETS	$	484,253		$	1,348,546
	LIABILITIES
	Current liabilities:
	Accrued expenses and other current		2,470			6,760
	Deferred revenue-current		730			1,150
	Amounts due to subsidiaries and VIEs		1,316			2,306
	Total current liabilities		4,516			10,216
	Deferred revenue-noncurrent		1,641			1,437
	Long-term debt		-			600,000
	TOTAL LIABILITIES	$	6,157		$	611,653
	EQUITY
	Qihoo 360 Technology Co. Ltd. shareholders' equity
	Class A ordinary shares ($0.001 par value; 378,000,000 and 378,000,000 shares authorized as of December 31, 2012 and 2013, respectively; 123,472,524 and 134,123,218 shares issued and outstanding as of December 31, 2012 and 2013, respectively)		123			134
	Class B ordinary shares ($0.001 par value; 122,000,000 and 122,000,000 shares authorized as of December 31, 2012 and 2013, respectively; 60,684,573 and 54,767,703 shares issued and outstanding as of December 31, 2012 and 2013, respectively)		61			55
	Treasury stock		-			(139	)
	Additional paid-in capital		420,662			568,675
	Accumulated other comprehensive income		9,114			20,380
	Retained earnings		48,136			147,788
	Total shareholders' equity		478,096			736,893
	TOTAL EQUITY		478,096			736,893
	TOTAL LIABILITIES AND EQUITY	$	484,253		$	1,348,546
		For the years ended December 31,
		2011			2012			2013
	Cost of revenues		16			4			-
	Operating expenses:
	Selling and marketing		31,473			21,289			15,519
	General and administrative		6,788			10,815			73,372
	Product development		12,283			21,782			38,211
	Total operating expenses		50,544			53,886			127,102
	Loss from operations		(50,560	)		(53,890	)		(127,102	)
	Interest income		1,662			4,702			6,341
	Interest expense		-			-			(5,551	)
	Other income		-			1,277			1,197
	Exchange  gain		6,514			412			5,100
	Impairment loss on long-term investments		(666	)		-			-
	Change in unrealized holding (loss) gain of trading securities		(220	)		(52	)		75
	Realized  gain from sales of trading securities		-			-			252
	Dividend income from a cost method investee		-			-			413
	Loss before income tax expense and earnings from subsidiary and VIEs		(43,270	)		(47,551	)		(119,275	)
	Income in earnings of subsidiaries and VIEs		58,873			94,639			219,247
	Income before income tax expense		15,603			47,088			99,972
	Income tax expense		-			(342	)		(320	)
	Net income attributable to Qihoo 360 Technology Co. Ltd.		15,603			46,746			99,652
	Accretion of Series A convertible participating redeemable preferred shares		203			-			-
	Accretion of Series B convertible participating redeemable preferred shares		313			-			-
	Accretion of Series C convertible participating redeemable preferred shares		255			-			-
	Net income attributable to ordinary shareholders of Qihoo 360 Technology Co. Ltd.	$	14,832		$	46,746		$	99,652
	For the years ended December 31,
	2011			2012			2013
Net income	$	15,603		$	46,746		$	99,652
Other comprehensive income, net of tax: Foreign currency translation adjustments		3,246			2,851			11,266
Other comprehensive income		3,246			2,851			11,266
Comprehensive income		18,849			49,597			110,918
Add: Comprehensive loss attributable to noncontrolling interest		-			-			-
Comprehensive income attributable to Qihoo 360 Technology Co. Ltd.	$	18,849		$	49,597		$	110,918
																		Total
																		Qihoo 360
													Accumulated		(Accumulated			Technology
										Additional			other		deficit)			Co. Ltd.
	Ordinary shares									paid-in			comprehensive		retained			shareholders'
	Shares			Amount			Treasury Stock			capital			income		earnings			equity
Balance as of January 1, 2011		71,560,740		$	72		$	-		$	12,568		$	3,017	$	(13,442	)	$	2,215
Accretion of Series A convertible participating redeemable preferred shares		-			-			-			-			-		(203	)		(203	)
Accretion of Series B convertible participating redeemable preferred shares		-			-			-			-			-		(313	)		(313	)
Accretion of Series C convertible participating redeemable preferred shares		-			-			-			-			-		(255	)		(255	)
Issuance of ordinary shares in connection with share-based compensation arrangements		3,059,779			3			-			-			-		-			3
Share-based compensation		-			-			-			47,989			-		-			47,989
Issuance of ordinary shares in connection with exercise of options		31,172			-			-			48			-		-			48
Issuance of ordinary shares upon initial public offering ("IPO"), net of offering costs of $2,342		26,063,544			26			-			231,523			-		-			231,549
Conversion of participating redeemable preferred shares to ordinary shares		78,314,016			78			-			70,893			-		-			70,971
Net income		-			-			-			-			-		15,603			15,603
Foreign currency translation adjustments		-			-			-			-			3,246		-			3,246
Balance as of December 31, 2011		179,029,251			179			-			363,021			6,263		1,390			370,853
Issuance of ordinary shares in connection with share-based compensation arrangements		3,512,394			3			-			-			-		-			3
Share-based compensation		-			-			-			50,605			-		-			50,605
Issuance of ordinary shares in connection with exercise of options		1,615,452			2			-			6,963			-		-			6,965
Disposal of noncontrolling interest in subsidiaries		-			-			-			73			-		-			73
Net income		-			-			-			-			-		46,746			46,746
Foreign currency translation adjustments		-			-			-			-			2,851		-			2,851
Balance as of December 31, 2012		184,157,097			184			-			420,662			9,114		48,136			478,096
Issuance of ordinary shares in connection with share-based compensation arrangements		561,517			1			-			-			-		-			1
Share repurchase		(14,544	)		-			(139	)		-			-		-			(139	)
Share-based compensation		-			-			-			121,087			-		-			121,087
Issuance of ordinary shares in connection with business acqusition		204,466			-			-			7,864			-		-			7,864
Issuance of ordinary shares in connection with exercise of options		3,982,385			4			-			19,067			-		-			19,071
Disposal of noncontrolling interest in subsidiaries		-			-			-			(5	)		-		-			-5
Net income		-			-			-			-			-		99,652			99,652
Foreign currency translation adjustments		-			-			-			-			11,266		-			11,266
Balance as of December 31, 2013		188,890,921		$	189		$	(139	)	$	568,675		$	20,380	$	147,788		$	736,893
	For the years ended December 31,
	2011			2012			2013
Cash flows from operating activities:
Net income		15,603			46,746			99,652
Adjustments to reconcile net income to net cash provided by operating activities:
Share-based compensation		47,989			50,605			121,087
Gain from investments in subsidiaries and VIEs		(58,873	)		(94,639	)		(219,247	)
Depreciation and amortization		243			582			1,476
Unrealized holding loss(gain) on trading securities		220			52			(75	)
Realized gain from sales of trading securities		-			-			(252	)
Dividend income from a cost method investee		-			-			(413	)
Loss from impairment of long-term investments		666			-			-
Prepaid expenses and other current assets		(352	)		(2,307	)		463
Deferred taxes		(457	)		(178	)		(53	)
Other noncurrent assets		-			-			743
Accrued expenses and other current liabilities		92			149			5,488
Deferred revenue		1,671			700			215
Amount due from/to subsidiaries and VIEs		(20	)		(21,816	)		(128,738	)
Net cash provided by (used in) operating activities		6,782			(20,106	)		(119,654	)
Cash flows from investing activities:
Restricted cash		-			(300	)		-
Purchase of intangible assets		-			(1,500	)		(1,500	)
Purchase of trading securities		(451	)		-			(510	)
Capital contribution for cost method investments		(929	)		(450	)		(15,760	)
Proceeds from sale of trading securities		-			-			762
Dividends received from a cost method investee		-			-			413
Investment in subsidiaries		(21,500	)		(1,200	)		-
Net cash used in investing activities		(22,880	)		(3,450	)		(16,595	)
Cash flows from financing activities:
Proceeds from issuance of Convertible Senior Notes (net of issuance cost of $12,150)		-			-			587,850
Proceeds from exercise of share options		20			2,089			23,678
Proceeds from issuance of ordinary shares upon IPO		234,312			-			-
Payment of IPO costs		(2,339	)		-			-
Payment for share repurchase		-			(139	)		-
Net cash provided by financing activities		231,993			1,950			611,528
Net increase (decrease) in cash and cash equivalents		215,895			(21,606	)		475,279
Cash and cash equivalents at beginning of year		25,947			241,842			220,236
Cash and cash equivalents at end of year		241,842			220,236			695,515

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Summary of Significant Accounting Policies [Abstract]	'
Basis of presentation	'
	Basis of presentation
	The consolidated financial statements of the Group have been prepared in accordance with accounting principles generally accepted in the United States of America ("US GAAP").
Basis of consolidation	'
	Basis of consolidation
	The consolidated financial statements of the Group include the financial statements of the Company, its wholly owned subsidiaries and VIEs and their subsidiaries. All inter-company transactions and balances have been eliminated upon consolidation.
Use of estimates	'
	Use of estimates
	The preparation of the consolidated financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and the reported amounts of revenues and expenses in the consolidated financial statements and accompanying notes. Significant accounting estimates reflected in the Group's consolidated financial statements include allowance for doubtful accounts, valuations of acquired intangible assets, share-based compensation, valuation allowances for deferred tax assets, impairment of long-term investments, impairment of long-lived assets, useful lives of definite-lived intangible assets and other long-lived assets as well as goodwill impairment assessment.
Fair value measurements	'
	Fair value measurements
	Authoritative literature provides a fair value hierarchy, which prioritizes the inputs to valuation techniques used to measure fair value into three broad levels. The level in the hierarchy within which the fair value measurement in its entirety falls is based upon the lowest level of input that is significant to the fair value measurement as follows:
		•	Level 1-inputs are based upon unadjusted quoted prices for identical instruments traded in active markets.
		•	Level 2-inputs are based upon quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation techniques for which all significant assumptions are observable in the market or can be corroborated by observable market data for substantially the full term of the assets or liabilities.
		•	Level 3-inputs are generally unobservable and typically reflect management's estimates of assumptions that market participants would use in pricing the asset or liability. The fair values are therefore determined using model-based techniques that include option pricing models, discounted cash flow models, and similar techniques.
	The Group measures certain assets, including the long-term investments and intangible assets, at fair value on a nonrecurring basis when they are deemed to be impaired. The fair values of these investments and intangible assets are determined based on valuation techniques using the best information available, and may include management judgments, future performance projections, etc. An impairment charge to the long-term investments is recorded when the cost of the investment exceeds its fair value and this condition is determined to be other-than-temporary, and impairment charge to the intangible assets is recorded when their carrying amounts may not be recoverable.
Cash and cash equivalents	'
	Cash and cash equivalents
	Cash and cash equivalents consist of cash on hand and term deposits, which are unrestricted as to withdrawal or use.
Trading securities	'
	Trading securities
	The securities that are bought and held principally for the purpose of selling them in the near term are classified as trading securities. Unrealized holding gains and losses for trading securities are included in the consolidated statements of operations.
Accounts receivable and allowance for doubtful accounts	'
	Accounts receivable and allowance for doubtful accounts
	Accounts receivable represents those receivables derived in the ordinary course of business. Allowance for doubtful accounts reflect the Group's best estimate of probable losses inherent in the accounts receivable balances. The Group regularly review allowances by considering factors such as historical experience, credit quality, the age of the accounts receivable balances and current economic conditions that may affect a customer's ability to pay.
Fair value of financial instruments	'
	Fair value of financial instruments
	Financial instruments primarily consist of cash and cash equivalents, restricted cash, trading securities, available-for-sale investment, accounts receivable, amounts due from related parties and accounts payable, amounts due to related parties, short-term loans and long-term debt. The carrying amounts of these financial instruments, except for long-term debt, approximate their fair values because of their generally short maturities.
Property and equipment, net	'
	Property and equipment, net
	Property and equipment is carried at cost less accumulated depreciation and amortization. Depreciation and amortization are calculated on a straightline basis over the following estimated useful lives:
	Computer equipment and application software		3 years
	Building		44 - 60 years
	Office building related facility and machines		10 - 15 years
	Furniture and vehicles		3 - 5 years
	Leasehold improvements		lesser of the lease term or the estimated
			useful life of the assets
	Property and equipment that are purchased or constructed which require a period of time before the assets are ready for their intended use are accounted for as construction-in-progress. Construction-in-progress is recorded at acquisition cost, including installation costs. Construction-in-progress is transferred to specific property and equipment accounts and commences depreciation when these assets are ready for their intended use.
Land use rights, net	'
	Land use rights, net
	All land in the PRC is owned by the PRC government, which, according to the relevant PRC law, may grant the right to use the land for a specified period of time. Payment for acquiring land use rights are stated at cost less accumulated amortization and any recognized impairment loss. Amortization is provided on a straight-line basis over the term of the land use rights.
Acquired intangible assets, net	'
	Acquired intangible assets, net
	Acquired intangible assets are estimated by management based on the fair value of assets acquired. Identifiable intangible assets are carried at cost less accumulated amortization. Amortization of definite-lived intangible assets is computed using the straight-line method over the following estimated useful lives, which are as follows:
	Domain names	3 - 10 years
	Source code	5 - 8 years
	Technology	2 - 10 years
	Non-compete agreement	1 - 5 years
	Trade mark	3 years
	Operating license	8 years
	Customer relationship	3 years
	User base	1 year
Impairment of long-lived assets	'
	Impairment of long-lived assets
	The Group evaluates the recoverability of long-lived assets, including identifiable intangible assets with determinable useful lives, whenever events or changes in circumstances indicate that a long-lived asset's carrying amount may not be recoverable. The Group measures the carrying amount of long-lived asset against the estimated undiscounted future cash flows associated with it. Impairment exists when the sum of the expected future net cash flows is less than the carrying value of the asset being evaluated. Impairment loss is calculated as the amount by which the carrying value of the asset exceeds its fair value. Fair value is estimated based on various valuation techniques, including the discounted value of estimated future cash flows. The evaluation of asset impairment requires the Group to make assumptions about future cash flows over the life of the asset being evaluated. These assumptions require significant judgment and actual results may differ from assumed and estimated amounts. During the years ended December 31, 2011, 2012 and 2013, the Group recognized $87, $1,151 and $107, respectively, of impairment losses on identifiable intangible assets with determinable useful lives. The related intangible assets are impaired in full when impairment indicators are noted.
Impairment of indefinite-lived intangible assets	'
	Impairment of indefinite-lived intangible assets
	An intangible asset that is not subject to amortization is tested for impairment at least annually or more frequently if events or changes in circumstances indicate that the asset might be impaired. Such impairment test is to compare the fair values of assets with their carrying amounts and an impairment loss is recognized if and when the carrying amounts exceed the fair values. The estimates of fair values of intangible assets not subject to amortization are determined using various discounted cash flow valuation methodologies. Significant assumptions are inherent in this process, including estimates of discount rates or market price. Discount rate assumptions are based on an assessment of the risk inherent in the respective intangible assets. Market prices are based on potential purchase quote from third party, if any. During the years ended December 31, 2011, 2012 and 2013, the Group recognized nil, $197 and $841, respectively, of impairment losses on its indefinite-lived intangible assets.
Goodwill	'
	Goodwill
	Goodwill represents the excess of the purchase price over the fair value of identifiable net assets acquired in business combinations. Goodwill is not amortized but is tested for impairment annually or more frequently if events or changes in circumstances indicate that it might be impaired.
	Goodwill is tested for impairment at the reporting unit level on an annual basis (December 31 for the Group) and between annual tests if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying value. These events or circumstances could include a significant change in the stock prices, business climate, legal factors, operating performance indicators, competition, or sale or disposition of a significant portion of a reporting unit.
	In the evaluation of the goodwill for impairment, the Group may first assess qualitative factors to determine whether it is "more likely than not" that the fair value of a reporting unit is less than its carrying amount as a basis for determining whether it is necessary to perform the two-step goodwill impairment test. If it is more likely than not that the fair value of a reporting unit is less than its carrying amount, goodwill is then tested following a two-step process.
	The first step compares the fair value of each reporting unit to its carrying amount, including goodwill. If the fair value of each reporting unit exceeds its carrying amount, goodwill is not considered to be impaired and the second step will not be required. If the carrying amount of a reporting unit exceeds its fair value, the second step compares the implied fair value of goodwill to the carrying value of a reporting unit's goodwill. The implied fair value of goodwill is determined in a manner similar to accounting for a business combination with the allocation of the assessed fair value determined in the first step to the assets and liabilities of the reporting unit. The excess of the fair value of the reporting unit over the amounts assigned to the assets and liabilities is the implied fair value of goodwill. An impairment loss is recognized for any excess in the carrying value of goodwill over the implied fair value of goodwill.
	Application of the goodwill impairment test requires judgment, including the identification of reporting units, assignment of assets and liabilities to reporting units, assignment of goodwill to reporting units, and determination of the fair value of each reporting unit. The estimation of fair value of each reporting unit using a discounted cash flow methodology also requires significant judgments, including estimation of future cash flows, which is dependent on internal forecasts, estimation of the long-term rate of growth for the Group's business, estimation of the useful life over which cash flows will occur, and determination of the Group's weighted average cost of capital. The estimates used to calculate the fair value of a reporting unit change from year to year based on operating results and market conditions. Changes in these estimates and assumptions could materially affect the determination of fair value and goodwill impairment for the reporting unit.
	In 2013, the Group assessed the qualitative factors to determine it is not " more likely than not" that the fair value of each reporting unit is less than its respective carrying amount. The Group did not incur any impairment loss on goodwill for the years ended December 31, 2011, 2012 and 2013.
Cost method investments	'
	Cost method investments
	For investee companies over which the Group does not have significant influence and a controlling interest, the Group carries the investment at cost and recognize as income for any dividend received from distribution of the investee's earnings.
	The Group reviews its cost method investments for impairment whenever an event or circumstance indicates that an other-than-temporary impairment has occurred. The Group considers available quantitative and qualitative evidence in evaluating potential impairment of its cost method investments. An impairment charge is recorded if the cost of an investment exceeds its fair value and such excess is determined to be other-than-temporary. The Group estimated the fair value of these investee companies based on discounted cash flow approach. Factors the Group considers in making such a determination include general market conditions, the duration and the extent to which the fair value of an investment is less than its cost, and the Group's intent and ability to hold such investment. As a result of the assessment process for its cost method investments, the Group recognized impairment charge of $666, $761 and $867 in 2011, 2012 and 2013, respectively.
Equity method investments	'
	Equity method investments
	Investee companies over which the Group has the ability to exercise significant influence, but does not have a controlling interest, are accounted for using the equity method. Significant influence is generally considered to exist when the Group has an ownership interest in the voting stock of the investee between 20% and 50%, and other factors, such as representation on the investee's board of directors, voting rights and the impact of commercial arrangements, are considered in determining whether the equity method of accounting is appropriate.
	An impairment charge is recorded if the carrying amount of the investment exceeds its fair value and this condition is determined to be other-than-temporary. The Group estimated the fair value of these investee companies based on discounted cash flow approach which requires significant judgments, including the estimation of future cash flows, which is dependent on internal forecasts, the estimation of long term growth rate of a company's business, the estimation of the useful life over which cash flows will occur, and the determination of the weighted average cost of capital. Certain of the equity method investments experience a deteriorating financial position and performance and the Group does not expect them to generate any positive future cash flows. Accordingly, the Group accrued an impairment charge of $236, $1,541 and $4,137 in 2011, 2012 and 2013, respectively, on these equity method investments based on their fair value which would be minimal.
Revenue recognition	'
	Revenue recognition
	The Group generates its revenue through internet services and sales of third party anti-virus software. The Group recognizes revenue when persuasive evidence of an arrangement exists, delivery has occurred, the sales price is fixed or determinable, and collectability is reasonably assured.
	Internet services revenue
	Internet services revenue includes online advertising, internet value-added services and other services.
		-1	Online advertising
	The Group offer marketing opportunities to customers by providing online advertising services, such as sponsored links (advertising links), on the Group's platform products, such as 360 Personal Start-up Page, 360 Search and 360 Mobile Assistant. The Group generally offer these advertising links to customers on a pay-for-effectiveness basis, which primarily includes a cost over time period model and cost for performance model. The Group charge fees to customers directly or indirectly determined based on the effectiveness of advertising links, which is typically measured by active users, clicks, transactions and other actions originated from the Group's platform products. Additionally, fees are also affected by, among other factors, (i) the competitiveness of bidding for sponsored links and keywords by customers, with more intensive bidding typically leading to higher pricing and (ii) the vertical industries that customers operate in, which may result in different effectiveness and benefits of the Group's online advertising services to customers.
	For advertising contracts that are charged on the cost over a time period, the Group recognizes revenue ratably over the period the advertising is provided. For contracts that are charged on the cost for performance, the revenue is estimated by the Group based on its internal data, which is confirmed with the respective customers.
	Prior to year 2013, the Group also directs search traffic to search engines such as Google through its default search boxes on the Group's 360 Browsers and its default home page, 360 Personal Start-up Page. The Group receives a pre-determined fee from search engine companies based on the number of searches originated from the search boxes in 360 Browsers and 360 Personal Start-up Page, subject to a pre-determined limit, from search engine companies. The revenue is estimated by the Group based on its traffic data, which is confirmed subsequently with the search engine companies. Since the Group launched its own search engine in August 2012 and subsequently terminated its service referral agreement with Google, revenue from search referral service has decreased to zero gradually.
	The Group engages in nonmonetary transactions such as to allow certain third parties to provide traffic on the non-monetization location of its platform products to show their brand or products in exchange for its brand promotion or more downloads of its platform or security products , and to allow certain third parties to bundle the Group's platform or security products with third parties' software products in exchange for more downloads of its platform or security products. The Group recognizes revenues and expenses at fair value from a nonmonetary transaction only if the fair value of the services exchanged in the transaction is determinable based on the entity's own historical practice of receiving cash, trading securities, or other consideration that is readily convertible to a known amount of cash for similar services from customers unrelated to the counterparty in the nonmonetary transaction. In 2011, the Group engaged in one nonmonetary transaction for which the fair value was determinable (see details in Note 9(ii)). Other than this transaction, for the years ended December 31, 2011, 2012 and 2013, the Group engaged in nonmonetary transactions for which the fair value was not determinable and therefore no revenues or expenses derived from these nonmonetary transactions were recognized.
		-2	Internet value-added services
	The Group's internet value-added services include offering games developed by third parties and providing other internet value-added services on the Group's platforms. Prior to May 2012, the Group also offers remote technical support to paying users.
	Games - The Group provides game services and generates revenue from selling in-game currency, which will be later used by game players to purchase in-game virtual items. The Group's game portfolio includes web games, client-based games and mobile games. All of the games are developed by third-party game developers and can be accessed and played by game players directly through the Group's game platform. The Group primarily views the game developers to be its customers and considers its responsibility under its agreements with the game developers to be promotion of the game developers' games. The Group generally collects payments from game players in connection with the sale of in-game currencies and remits certain agreed-upon percentages of the proceeds to the game developers and records revenue net of remittances. Revenue from the sale of in-game currency is primarily recorded net of remittances to game developers and deferred until the estimated consumption date, (i.e., the estimated date in-game currencies are consumed within the game), which is typically within a short period of time after purchase of the in-game currency. Purchases of in-game currency are not refundable after they have been sold unless there is unused in-game currency at the time a game is discontinued. Typically, a game will only be discontinued when the monthly revenue generated by a game is insignificant. To date, the Group has never been required to pay cash refunds to game players or game developers as a result of the discontinuation of a game.
	Other internet value-added services - The Group provides online lottery purchase services and serves as an agent for providing online distribution services and payment collection services on behalf of third-parties, such as collection payment for mobile charges, e-books and etc. The Group provides payment collection services mainly through third-party professional payment and settlement institutions. The Group generally charges commission as a percentage of the gross proceeds or collection amount, and the revenue is estimated by the Group based on its internal system, which is confirmed with the respective cooperators.
	Remote technical support - The Group provides live technical assistance on a broad range of computer issues relating to security and performance optimization through remote access to users' computers. The Group generally charges fees on a per case basis for this service and also provides monthly and annual subscriptions. For services charged on a per case basis, the Group recognizes revenue when the service is provided. For monthly and annual subscriptions, the Group recognizes revenue ratably over the life of the subscription. Starting from May 2012, the Group offers remote technical support services for free and refunds prepaid fees to users.
	Sales of third party anti-virus software
	The Group purchases software, such as anti-virus software, from third-party software developers for online distribution to users. The Group recognizes revenue when the activation code of the software is delivered. The Group evaluates its software sales contracts to determine whether to recognize revenues on a gross basis or net of costs of obtaining the associated software. The determination is based upon an assessment as to whether the Group acts as a principal or agent when providing the sales. After an agreement with a third-party developer was expired in April 2012, the Group's sales of third party anti-virus software has been insignificant.
Deferred revenue	'
	Deferred revenue
	Deferred revenue primarily includes cash received in advance from customers or end users and unrecognized license fee related to a license granted under a nonmonetary transaction as described in Note 9(ii), and deferred subsidy income. The unused cash balances remaining in customers or users' accounts are recorded as a liability. Deferred revenues related to prepayments from third party customers or end users will be recognized as revenue when all of the revenue recognition criteria are met, and deferred revenue related to license fee will be recognized as revenue based on the contract term.
Costs of revenues	'
	Costs of revenues
	Cost of revenues primarily consists of business tax, value added tax ("VAT") and related surcharges, payment collection costs, traffic acquisition costs, salaries and benefits, bandwidth costs, depreciation of equipment and revenue sharing to third party partners.
	Business tax and related surcharges by various Chinese local tax authorities are incurred at rates ranging from 3.39% to 8.70% on revenue generated from providing services.
	In July 2012, the Ministry of Finance and the State Administration of Taxation jointly issued a circular regarding the pilot collection of VAT in lieu of business tax in certain areas and industries in the PRC. Such VAT pilot program was to be phased in Beijing and Tianjin in September and December 2012, respectively. Starting from September 1, 2012, certain subsidiaries and VIEs of the Group became subject to VAT and related surcharges by various Chinese local tax authorities at rates ranging from 3.00% to 19.04% on revenue generated from providing services which were previously subject to business tax.
	Business tax and VAT included in revenues and cost of revenues for the years ended December 31, 2011, 2012 and 2013 were $9,078, $18,434 and $39,909, respectively.
Product development expenses	'
	Product development expenses
	The product development expenses primarily consist of the research and development expenses and expenses incurred for strengthening the existing products. Product development primarily focused on the development and enhancement of security products, cloud-based services, search engine related products, mobile internet products and other internet products, platforms and services.
	Product development expenses include personnel-related expenses, bandwidth, license and technical service fees, depreciation of property and equipment and amortization of acquired intangible assets. The Group expenses product development costs as incurred.
Advertising costs	'
	Advertising costs
	Advertising costs are expensed as incurred. The Group incurred advertising costs of $7,843, $21,082 and $62,301 for the years ended December 31, 2011, 2012 and 2013, respectively, which were recorded as a component of selling and marketing expenses in the accompanying consolidated statements of operations.
Operating leases	'
	Operating leases
	Leases where the rewards and risks of ownership of assets primarily remain with the lessor are accounted for as operating leases. Payments made under operating leases are charged to the consolidated statements of operations on a straight-line basis over the lease periods.
Subsidy income	'
	Subsidy income
	Government subsidy is recorded as a liability in deferred revenue when received, and recognized as subsidy income when the project is inspected and confirmed by the government, or it is not subject to future return or reimbursement. The Group recognized subsidy income of $151, $2,570 and $2,349 for the years ended December 31, 2011, 2012 and 2013, respectively.
Income taxes	'
	Income taxes
	The Group follows the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial reporting and tax basis of assets and liabilities using enacted tax rates that will be in effect for the period in which the differences are expected to reverse. The Group records a valuation allowance against the amount of deferred tax assets that it determines is not more-likely-than-not of being realized. The effect on deferred taxes of a change in tax rates is recognized in the consolidated statements of operations in the period that includes the enactment date.
	The impact of an uncertain income tax position on the income tax return is recognized at the largest amount that is more-likely-than-not to be sustained upon audit by the relevant tax authority. An uncertain income tax position will not be recognized if it has less than a 50% likelihood of being sustained. Interest and penalties on income taxes will be classified as a component of the provisions for income taxes.
Net income per share	'
	Net income per share
	Basic net income per share is computed by dividing net income attributable to ordinary shareholders by the weighted average number of ordinary shares outstanding during the year excluding any outstanding ordinary shares that are contingently refundable subject to the satisfaction of both the service and performance condition on the nonvested shares. Diluted net income per share reflects the potential dilution that could occur if securities or other contracts to issue ordinary shares were exercised or converted into ordinary shares.
	The Company computes earnings per Class A and Class B ordinary shares using the two-class method. The unvested portions of nonvested shares are participating securities as all outstanding nonvested shares are entitled to nonforfeitable dividends that participate in undistributed earnings with ordinary shares. Since the nonvested shares are considered participating securities, the nonvested shares issued by the Company are required to apply the two-class method when computing basic earnings per share.
	The Group has share options, nonvested shares and convertible senior notes which could potentially dilute basic earnings per share in the future. To calculate the number of shares for diluted net income per share, the effect of the share options is computed using the treasury stock method. The dilutive effect of the convertible senior notes is computed using as-if converted method.
Foreign currency translation	'
	Foreign currency translation
	The functional and reporting currency of the Company is the United States dollar ("U.S. dollar"). The financial records of the Company's subsidiaries, VIEs and VIEs' subsidiaries located in the PRC are maintained in its local currency, the Renminbi ("RMB") which is the functional currency of these entities. The financial records of the Company's subsidiaries located in Hong Kong are maintained in U.S. dollar which is the functional currency of these entities.
	Monetary assets and liabilities denominated in currencies other than the functional currency are translated into the functional currency at the rates of exchange ruling at the balance sheet date. Transactions in currencies other than the functional currency during the year are converted into functional currency at the applicable rates of exchange prevailing when the transactions occurred. Transaction gains and losses are recognized in the consolidated statements of operations.
	The Group's entities with functional currency of RMB translate their operating results and financial position into the U.S. dollar, the Company's reporting currency. Assets and liabilities are translated using the exchange rates in effect on the balance sheet date. Equity amounts are translated at historical exchange rates, and revenues, expenses, gains and losses are translated using the average rate for the year. Translation adjustments are reported as cumulative translation adjustments and are shown as a separate component of other comprehensive income in the consolidated statements of changes in equity and comprehensive income.
Comprehensive income	'
	Comprehensive income
	Comprehensive income of the Group includes the cumulative foreign currency translation adjustments and net income for the year. Comprehensive income is reported in the statements of comprehensive income.
Share-based compensation	'
	Share-based compensation
	Share-based compensation with employees is measured based on the grant date fair value of the equity instrument. The Group recognizes the compensation costs net of an estimated forfeiture rate using the straight-line method, over the requisite service period of the award, which is generally the vesting period of the award. The estimate of forfeitures will be adjusted over the requisite service period to the extent that actual forfeitures differ, or are expected to differ, from such estimates. Changes in estimated forfeitures will be recognized through a cumulative catch-up adjustment in the period of change and will also impact the amount of share-based compensation expense to be recognized in future periods.
	Share awards issued to nonemployees are measured at fair value at the earlier of the commitment date or the date the services is completed and recognized over the period the service is provided or as goods is received.
	The Group uses the Black-Scholes or Binomial-Model option pricing model to measure the value of options granted to employees and nonemployees at each grant date or measurement date.
Treasury stock	'
	Treasury stock
	Treasury stock represents ordinary shares repurchased by the Group that are no longer outstanding and are held by the Group. The repurchase of ordinary shares is accounted for under the cost method whereby the entire cost of the acquired stock is recorded as treasury stock.
Risks and uncertainties	'
	Risks and uncertainties
	The Group participates in a dynamic industry with rapid changes in regulations, technology trends, customer demand and competition and believes that changes in any of the following areas could have a material adverse effect on the Group's future financial position, results of operations, or cash flows: advances and trends in new technologies and industry standards; changes in certain strategic relationships or customer relationships; regulatory or other PRC related factors; risks associated with the Group's ability to attract and retain certain necessary employees to support its growth; risks associated with the Group's ability to keep and increase the user base; risks associated with the Group's growth strategies and general risks associated with the internet security industry, and risks surrounding pending litigations.
Concentration of credit risk	'
	Concentration of credit risk
	Financial instruments that potentially expose the Group to concentrations of credit risk consist primarily of cash and accounts receivable. The Group places its cash with financial institutions with high-credit ratings and quality. The Group conducts credit evaluations of customers and generally does not require collateral or other security from their customers. The Group maintains reserves for potential credit losses.
	Details of the customers that account for 10% or more of total revenues are as follow:
			Year ended December 31,
			2011			2012			2013
	Customer
	A			10	%		5	%		*-
	B			11	%		10	%		*-
	Details of the customers accounting for 10% or more of accounts receivable are as follows:
			December 31,
			2012			2013
	Customer
	B			29	%		32	%
	C			12	%		*-
	“*” means less than 10%
Newly adopted accounting pronouncements	'
	Newly adopted accounting pronouncements
	In July 2012, the FASB has issued an authoritative pronouncement related to testing indefinite-lived intangible assets, other than goodwill, for impairment. Under the pronouncement, entities testing indefinite-lived intangible assets for impairment would have the option of performing a qualitative assessment before calculating the fair value of the asset. If an entity determines, on the basis of qualitative factors, that the indefinite-lived intangible asset is not more likely than not impaired, a quantitative fair value calculation would not be needed. The amendments are effective for annual and interim impairment tests performed for fiscal years beginning after September 15, 2012. The adoption of this guidance did not have a significant effect on the Group's consolidated financial statements.
	In February 2013, the FASB issued an authoritative pronouncement related to reporting of amounts reclassified out of accumulated other comprehensive income, to improve the transparency of reporting these reclassifications. Other comprehensive income includes gains and losses that are initially excluded from net income for an accounting period. Those gains and losses are later reclassified out of accumulated other comprehensive income into net income. The amendments in this ASU do not change the current requirements for reporting net income or other comprehensive income in financial statements. All of the information that this ASU requires already is required to be disclosed elsewhere in the financial statements under US GAAP.
	The new amendments will require an organization to:
	• Present (either on the face of the statement where net income is presented or in the notes) the effects on the line items of net income of significant amounts reclassified out of accumulated other comprehensive income—but only if the item reclassified is required under US GAAP to be reclassified to net income in its entirety in the same reporting period.
	• Cross-reference to other disclosures currently required under US GAAP for other reclassification items (that are not required under US GAAP) to be reclassified directly to net income in their entirety in the same reporting period. This would be the case when a portion of the amount reclassified out of accumulated other comprehensive income is initially transferred to a balance sheet account (e.g., inventory for pension-related amounts) instead of directly to income
	or expense.
	The amendments apply to all public and private companies that report items of other comprehensive income. Public companies are required to comply with these amendments for all reporting periods (interim and annual). The amendments are effective for reporting periods beginning after December 15, 2012, for public companies. Early adoption is permitted. The Group adopted this pronouncement on January 1, 2013 which did not have a significant impact on its consolidated financial statements.
Recently issued accounting pronouncements not yet adopted	'
	Recently issued accounting pronouncements not yet adopted
	In July 2013, the FASB issued a pronouncement which provides guidance on financial statement presentation of an unrecognized tax benefits when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. The FASB’s objective in issuing this Accounting Standards Updates (‘‘ASU’’) is to eliminate diversity in practice resulting from a lack of guidance on this topic in current US GAAP. The amendments in this ASU state that an unrecognized tax benefit, or a portion of an unrecognized tax benefit, should be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward, except as follows. To the extent a net operating loss carryforward, a similar tax loss, or a tax credit carryforward is not available at the reporting date under the tax law of the applicable jurisdiction to settle any additional income taxes that would result from the disallowance of a tax position or the tax law of the applicable jurisdiction does not require the entity to use, and the entity does not intend to use, the deferred tax asset for such purpose, the unrecognized tax benefit should be presented in the financial statements as a liability and should not be combined with deferred tax assets.
	This ASU applies to all entities that have unrecognized tax benefits when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists at the reporting date. The amendments in this ASU are effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. Early adoption is permitted. The amendments should be applied prospectively to all unrecognized tax benefits that exist at the effective date. Retrospective application is permitted.
	The Group does not expect the adoption of this guidance will have a significant effect on its consolidated financial statements.

Organization_and_Principal_Act1

Organization and Principal Activities (Tables)	12 Months Ended
	Dec. 31, 2013
Organization and Principal Activities [Abstract]	'
Schedule of Variable Interest Entities	'
		December 31,
		2012			2013
	Cash and cash equivalents	$	58,108		$	116,575
	Restricted cash		1,605			2,068
	Account receivable and other current assets		34,976			61,177
	Total current assets		94,689			179,820
	Property and equipment, net		57,275			91,861
	Acquired intangible assets, net		5,113			9,681
	Other noncurrent assets		26,814			37,778
	Total noncurrent assets		89,202			139,320
	Total assets		183,891			319,140
	Deferred revenue, current		17,520			30,717
	Account payable and other current liabilities		51,455			106,894
	Total current liabilities		68,975			137,611
	Total noncurrent liabilities		3,613			2,235
	Total liabilities	$	72,588		$	139,846
		Year ended December 31,
		2011			2012			2013
	Revenues	$	160,613		$	303,200		$	527,646
	Net income	$	78,494		$	150,408		$	263,514
		Year ended December 31,
		2011			2012			2013
	Net cash provided by operating activities	$	56,621		$	75,983		$	129,175
	Net cash used in investing activities		(32,367	)		(50,951	)		(72,678	)
	Net cash provided by financing activities		1,545			36			1,970
		$	25,799		$	25,068		$	58,467

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2013
Summary of Significant Accounting Policies [Abstract]	'
Property and Equipment, Estimated Useful Lives	'
	Computer equipment and application software		3 years
	Building		44 - 60 years
	Office building related facility and machines		10 - 15 years
	Furniture and vehicles		3 - 5 years
	Leasehold improvements		lesser of the lease term or the estimated
			useful life of the assets
Acquired Intangible Assets, Estimated Useful Lives	'
	Domain names	3 - 10 years
	Source code	5 - 8 years
	Technology	2 - 10 years
	Non-compete agreement	1 - 5 years
	Trade mark	3 years
	Operating license	8 years
	Customer relationship	3 years
	User base	1 year
Total revenue [Member] | Credit Concentration Risk [Member]	'
Concentration Risk [Line Items]	'
Concentration of Credit Risk	'
			Year ended December 31,
			2011			2012			2013
	Customer
	A			10	%		5	%		*-
	B			11	%		10	%		*-
	“*” means less than 10%
Accounts receivable [Member] | Credit Concentration Risk [Member]	'
Concentration Risk [Line Items]	'
Concentration of Credit Risk	'
			December 31,
			2012			2013
	Customer
	B			29	%		32	%
	C			12	%		*-
	“*” means less than 10%

Acquisition_Tables

Acquisition (Tables)	12 Months Ended
	Dec. 31, 2013
Business Acquisition [Line Items]	'
Business Acquisition, Purchase Price Allocation	'
Internet service company with 80% equity interest owned by Group [Member]	'
Business Acquisition [Line Items]	'
Business Acquisition, Purchase Price Allocation	'
		US$
	Cash	$	387
	Other net assets acquired, excluding intangible assets and related deferred tax liabilities		(9	)
	Intangible assets
	Technology		2,451
	Trade mark		866
	Deferred tax liability		(829	)
	Goodwill		8,762
	Fair value of 20% equity interests owned by the Group		(1,831	)
	Non-Controlling Interest		(1,831	)
	Total	$	7,966
Business Acquisition, Pro Forma Information	'
		Year ended December 31,
		2012			2013
		(Unaudited)			(Unaudited)
	Pro forma revenue	$	329,591		$	671,429
	Pro forma net income	$	45,938		$	98,582
	Pro forma earnings per ordinary share-basic	$	0.26		$	0.55
	Pro forma earnings per ordinary share-diluted	$	0.25		$	0.51
Overseas internet service company [Member]	'
Business Acquisition [Line Items]	'
Business Acquisition, Purchase Price Allocation	'
		US$
	Cash	$	687
	Other net assets acquired, excluding intangible assets and the related deferred tax liabilities		1,512
	Intangible assets
	Customer relationship		3,147
	Technology		535
	User base		129
	Goodwill		8,319
	Deferred tax liability		(1,069	)
	Non-Controlling Interest		(5,396	)
	Total	$	7,864
Business Acquisition, Pro Forma Information	'
		Year ended December 31,
		2012			2013
		(Unaudited)			(Unaudited)
	Pro forma revenue	$	336,215		$	675,981
	Pro forma net income	$	44,940		$	99,001
	Pro forma earnings per ordinary share-basic	$	0.25		$	0.55
	Pro forma earnings per ordinary share-diluted	$	0.24		$	0.51
Internet service company with 51% equity interest owned by Group [Member]	'
Business Acquisition [Line Items]	'
Business Acquisition, Purchase Price Allocation	'
		US$
	Cash	$	10,169
	Other net assets acquired, excluding intangible assets and related deferred tax liabilities		80
	Intangible assets
	Technology		1,188
	User base		27
	Goodwill		6,346
	Deferred tax liability		(304	)
	Non-Controlling Interest		(7,506	)
	Total	$	10,000
Business Acquisition, Pro Forma Information	'
		Year ended December 31,
		2012			2013
		(Unaudited)			(Unaudited)
	Pro forma revenue	$	329,032		$	671,180
	Pro forma net income	$	46,471		$	97,658
	Pro forma earnings per ordinary share-basic	$	0.26		$	0.54
	Pro forma earnings per ordinary share-diluted	$	0.25		$	0.51

Restricted_Cash_Tables

Restricted Cash (Tables)	12 Months Ended
	Dec. 31, 2013
Restricted Cash [Abstract]	'
Restricted Cash	'
			December 31,
			2012		2013
	Deposits for registration of new subsidiaries of VIEs (i)		$	1,605	$	1,652
	Deposit used to secure for bank's acceptance bills in relation to payment for the construction of a building			-		416
	Deposits used to secure for application of an operation right			300		300
	Total		$	1,905	$	2,368
		(i)	The balance represented the deposits placed in certain escrow accounts for registration of new VIEs’ wholly owned subsidiaries.

Accounts_Receivable_Tables

Accounts Receivable (Tables)	12 Months Ended
	Dec. 31, 2013
Accounts Receivable [Abstract]	'
Schedule of Accounts Receivable	'
		December 31,
		2012			2013
	Accounts receivable	$	23,804		$	54,743
	Allowance for doubtful accounts		(213	)		(145	)
	Accounts receivable, net	$	23,591		$	54,598
Movement of Allowance for Doubtful Accounts	'
		December 31,
		2011			2012			2013
	Balance at beginning of year	$	14		$	68		$	213
	Charge to expenses		51			154			157
	Write offs during the year		-			(10	)		(229	)
	Exchange rate differences		3			1			4
	Balance at end of year	$	68		$	213		$	145

Prepaid_expenses_and_other_cur1

Prepaid expenses and other current assets (Tables)	12 Months Ended
	Dec. 31, 2013
Prepaid expenses and other current assets [Abstract]	'
Prepaid Expenses and Other Current Assets	'
			December 31,
			2012		2013
	Guarantee loan to employees related to exercise of share options (i)		$	753	$	29,188
	Receivables of exercise cost share options (ii)			4,907		301
	Prepaid principal for investments (iii)			1,003		10,534
	Advance to suppliers			4,205		9,804
	Deductible VAT Input			7,895		9,650
	Prepaid marketing promotion fee			515		7,034
	Interest receivable			1,086		3,219
	Advance related to employees			1,011		2,146
	Others			5,427		8,662
	Total		$	26,802	$	80,538
		(i)	Amount represents the individual income tax paid by the Group on behalf of employees associated with the options and nonvested shares granted by the Company. Such receivable is secured by share options or nonvested shares held by the employees, and will be repaid to the Company when the options are exercised and related ordinary shares are sold.
		(ii)	Amount represents the exercise cost to be received by the Group from a trading institution after the Group's employees exercised their stock options through such institution.
		(iii)	The Group made several payments to establish new companies with other independent third parties. The prepayments will be recorded as long-term investments when the investees are legally established.

Longterm_Investments_Tables

Long-term Investments (Tables)	12 Months Ended
	Dec. 31, 2013
Long-term Investments [Abstract]	'
Long-term Investments	'
			December 31,
			2012			2013
	Cost method investments:
	An internet service company, Investee D (i)		$	-		$	15,000
	Others			13,989			33,306
	Less: impairment loss on long-term investments (iii)			(1,427	)		(2,294	)
	Cost method investments, net		$	12,562		$	46,012
	Equity method investments:
	An internet security company, Investee E (ii)		$	1,761		$	24,099
	Others			14,777			19,264
	Less: impairment loss on long-term investments (iv)			(1,541	)		(5,082	)
	Equity method investments, net			14,997			38,281
	Total		$	27,559		$	84,293
		(i)	In December 2013, the Group invested in Investee D to purchase 4.13% of its ordinary shares for purchase prices of $15,000. The Group used the cost method of accounting to record these investments since the Group does not have the ability to exercise significant influence over the operating and financing activities. The management of the Group determined that there was no impairment on such investments during the year ended December 31, 2013.
		(ii)	In November 2011, the Group entered into a nonmonetary transaction with Investee E. The Group provides the license for using the Group's certain technology licenses to Investee E in exchange for its 30% equity interest in the form of preferred shares. The Group also needs to provide continuous technical support to the investee for ten years. Because the fair value of the licenses is more readily determinable, the Group recorded the transaction based on the fair value of the license which was valued with the assistance of a third-party valuation firm. The fair value was determined as $3,000. The transaction was accounted for as an equity method investment since the Group has the ability to exercise significant influence over the operating and financing activities of Investee E. The partial gain of the nonmonetary transaction was recorded as deferred revenue and is amortized ratably over the ten year contract period. In June 2012, the Group made an additional investment in Investee E for an aggregate price of $2,140 in cash to avoid diluting in its series B financing. In December 2013, the Group made another additional investment in Investee E for an aggregate price of $25,000 in cash in its series C financing. As of December 31, 2013, the Group held 40.8% equity interest in Investee E. The Group recognized $142, $2,337 and $2,661 share of loss in 2011, 2012 and 2013, respectively. The management of the Group determined that there was no impairment on such investment during the years ended December 31, 2011, 2012 and 2013.
		(iii)	The Group reviews its cost method investments for impairment whenever an event or circumstance indicates that an other-than-temporary impairment has occurred. The Group considers available quantitative and qualitative evidence in evaluating potential impairment of its cost method investments. An impairment charge is recorded if the cost of an investment exceeds its fair value and such excess is determined to be other-than-temporary. The Group estimated the fair value of these investee companies based on discounted cash flow approach. Factors the Group considers in making such a determination include general market conditions, the duration and the extent to which the fair value of an investment is less than its cost, and the Group's intent and ability to hold such investment. As a result of the assessment process for its cost method investments, the Group recognized impairment charge of $666, $761 and $867 million in 2011, 2012 and 2013, respectively for certain cost method investments as their financial positions and performance of these investee companies are deteriorating and the Group does not expect them to generate any positive future cash flows. Accordingly, the Group estimated the fair values of these investee companies would be minimal.
		(iv)	An impairment charge is recorded if the carrying amount of the equity method investment exceeds its fair value and this condition is determined to be other-than-temporary. The Group estimated the fair value of these investee companies based on discounted cash flow approach which requires significant judgments, including the estimation of future cash flows, which is dependent on internal forecasts, the estimation of long term growth rate of a company’s business, the estimation of the useful life over which cash flows will occur, and the determination of the weighted average cost of capital. Certain of the equity method investments experience a deteriorating financial position and performance and the Group does not expect them to generate any positive future cash flows. Accordingly, the Group accrued an impairment charge of $236, $1,541 and $4,137 in 2011, 2012 and 2013 on these equity method investments based on their fair value which would be minimal.

Property_and_equipment_net_Tab

Property and equipment, net (Tables)	12 Months Ended
	Dec. 31, 2013
Property and equipment, net [Abstract]	'
Property and Equipment, Net	'
			December 31,
			2012		2013
	Computer equipment and application software		$	81,023	$	149,877
	Building (i)			45,050		46,471
	Office building related facility and machines (i)			13,212		14,022
	Furniture and vehicles			4,422		4,672
	Leasehold improvements			1,038		1,354
	Construction in Progress (ii)			-		5,469
				144,745		221,865
	Less: Accumulated depreciation and amortization			18,710		58,001
	Property and equipment, net		$	126,035	$	163,864
		(i)	In August 2012, the Group entered into a series of definitive agreements to purchase two parcels of office buildings and the associated land use rights with an area of approximately 69,205 square meters in Chaoyang District, Beijing, China for a total cash consideration of $222 million. The Group completed the acquisition of one parcel of the buildings in 2012 and the acquisition of the other parcel of buildings was in process as of December 31, 2013. The Group capitalized the related building cost of $43,927 and the cost for the facilities of the first parcel of building of $13,212 in the year ended December 31, 2012. No building cost and facilities cost were capitalized in year 2013.
		(ii)	As part of the acquisition of Entity P in 2013 as described in Note 3(4), the Group acquired a building under construction at Henan Province of China.

Land_Use_Rights_Net_Tables

Land Use Rights, Net (Tables)	12 Months Ended
	Dec. 31, 2013
Land Use Rights, Net [Abstract]	'
Land Use Rights, Net	'
		December 31,
		2012		2013
	Land use rights	$	73,785	$	77,590
	Less: accumulated depreciation and amortization		140		1,892
	Land use rights, net	$	73,645	$	75,698

Acquired_Intangible_Assets_Net1

Acquired Intangible Assets, Net (Tables)	12 Months Ended
	Dec. 31, 2013
Acquired Intangible Assets, Net [Abstract]	'
Definite-lived Intangible Assets	'
		December 31,
		2012			2013
	Definite-lived:
	Domain names	$	2,426		$	2,482
	Source code		1,754			1,662
	Technology		6,999			12,013
	Non-compete agreement		3,933			3,985
	Operating License		610			1,768
	Trademarks		77			79
	User Base		-			157
	Customer relationship		-			2,973
	Total acquired definite-lived intangible assets		15,799			25,119
	Less: Accumulated amortization
	Domain names		(423	)		(859	)
	Source code		(821	)		(1,050	)
	Technology		(1,872	)		(3,450	)
	Non-compete agreement		(299	)		(1,584	)
	Trademarks		(2	)		(29	)
	Operating license		-			(235	)
	User base		-			(8	)
	Customer relationship		-			(507	)
	Accumulated amortization		(3,417	)		(7,722	)
	Less: Impairment loss
	Domain names		(411	)		(424	)
	Source code		(158	)		(72	)
	Technology		(673	)		(887	)
	Accumulated impairment loss		(1,242	)		(1,383	)
	Acquired definite-lived intangible assets, net	$	11,140		$	16,014
Indefinite-lived Intangible Assets	'
		December 31,
		2012			2013
	Indefinite-lived:
	Domain names	$	360		$	371
	Trademarks		1,288			2,200
	Total acquired indefinite-lived intangible assets		1,648			2,571
	Less: Impairment loss
	Domain names		(281	)		(288	)
	Trademarks		(197	)		(1,049	)
	Accumulated impairment loss		(478	)		(1,337	)
	Acquired indefinite-lived intangible assets, net	$	1,170		$	1,234

Goodwill_Tables

Goodwill (Tables)	12 Months Ended
	Dec. 31, 2013
Goodwill [Abstract]	'
Goodwill	'
		2012		2013
	Beginning balance	$	4,580	$	4,628
	Goodwill acquired in acquisitions of business		-		24,992
	Exchange rate differences		48		(111	)
	Ending balance	$	4,628	$	29,509

Accrued_expenses_and_other_cur1

Accrued expenses and other current liabilities (Tables)	12 Months Ended
	Dec. 31, 2013
Accrued expenses and other current liabilities [Abstract]	'
Accrued Expenses and Other Current Liabilities	'
		December 31,
		2012		2013
	Payable for purchasing plant, property and equipment	$	59,703	$	20,419
	Payable for purchasing intangible assets		3,340		442
	Payable for purchasing land use rights		62,717		-
	Payroll related payable		13,446		19,217
	Accrued agent rebates and profit sharing cost		1,723		16,891
	Accrued marketing promotion expenses		6,102		13,965
	Other tax payable		2,616		12,094
	Deposits from advertising customers		1,376		10,060
	Accrued bandwidth		9,052		8,566
	Accrued professional service fee		3,145		6,640
	Accrued interest expenses of convertible senior notes (see note 17)		-		4,808
	Other current liabilities		5,326		7,316
	Total	$	168,546	$	120,418

Deferred_Revenue_Tables

Deferred Revenue (Tables)	12 Months Ended
	Dec. 31, 2013
Deferred Revenue [Abstract]	'
Deferred Revenue	'
			December 31,
			2012		2013
	Deferred revenue - current:
	Deferred revenue from customers (i)		$	14,915	$	31,503
	Deferred revenue for system development services (ii)			1,102		2,266
	Deferred subsidy income (iii)			4,093		11,503
	Deferred license fee (iv)			210		210
	Deferred reimbursement of ADS depositary service (v)			729		1,150
	Total deferred revenue - current		$	21,049	$	46,632
	Deferred revenue - noncurrent
	Deferred license fee (iv)		$	1,654	$	1,444
	Deferred revenue for system development services (ii)			408		168
	Deferred subsidy income (iii)			3,059		495
	Deferred reimbursement of ADS depositary service (v)			1,641		1,437
	Total deferred revenue - noncurrent		$	6,762	$	3,544
		(i)	Deferred revenue from customers mainly represents payments received from (1) advertising customers before the services were provided by the Group; and (2) game players before the in-game currency were consumed.
		(ii)	Deferred revenue for system development services represents payments received from third party customers in relation to the service to be provided by the Group which is subject to the customers' inspection and acceptance.
		(iii)	The Group received subsidies from the local government for web-security related research and development projects. The amount was deferred since the projects are subject to final inspection upon the completion.
		(iv)	Deferred license fee was related to the nonmonetary transaction as described in Note 9(ii).
		(v)	Deferred reimbursement of ADS depositary service represents the cash received from the Bank of New York Mellon as reimbursement of its ADS depositary service, which will be recognized ratably over the ADS contract term.

Longterm_Debt_Tables

Long-term Debt (Tables)	12 Months Ended
	Dec. 31, 2013
Long-term Debt [Abstract]	'
Long-term Debt	'
		For the year ended December 31, 2013
	Interest expense at an annual rate of 2.50%	$	4,808
	Amortization of debt issuance costs		743
	Total interest expense	$	5,551

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Taxes [Abstract]	'
Components of Income Tax Expense	'
		For the year ended December 31,
		2011			2012			2013
	Current income tax expense	$	10,724		$	12,062		$	22,382
	Deferred income tax expense (benefit)		150			(683	)		1,041
	Total income tax expense	$	10,874		$	11,379		$	23,423
Components of Deferred Tax Assets and Liabilities	'
		December 31,
		2012			2013
	Current deferred tax assets:
	Accrued payroll	$	1,950		$	2,889
	Provision of allowance for doubtful accounts		125			92
	Deferred revenue-current		196			306
	Less: Valuation allowance		(140	)		(158	)
	Current deferred tax assets, net		2,131			3,129
	Noncurrent deferred tax assets:
	Deferred revenue-noncurrent		440			383
	Acquired intangible assets		175			266
	Fixed assets		-			66
	Subsidy income		130			231
	Net operating loss carry forwards		975			4,592
	Less: Valuation allowance		(975	)		(4,592	)
	Noncurrent deferred tax assets, net		745			946
	Noncurrent deferred tax liabilities:
	Acquired intangible assets		425			2,676
	Subsidy income		365			-
	Noncurrent deferred tax liabilities	$	790		$	2,676
Effective Income Tax Rate Reconciliation	'
		For the year ended December 31,
		2011			2012			2013
	Income before income tax expense	$	25,855		$	62,695		$	124,019
	PRC statutory income tax rate		25	%		25	%		25	%
	Income tax expense at the statutory income tax rate		6,464			15,674			31,005
	Permanent differences		116			870			1,663
	Effect of different income tax calculation method required by tax bureau		(84	)		67			48
	Effect of tax exempt status in Cayman Islands		10,818			12,217			30,272
	Effect of different income tax rate in Hong Kong		(233	)		(25	)		168
	Effect of tax exempt status in other jurisdictions		-			-			(31	)
	Effect of income tax holiday and preferential tax rates		(7,036	)		(17,844	)		(43,460	)
	Changes in valuation allowance		829			420			3,758
	Income tax expense	$	10,874		$	11,379		$	23,423

Net_Income_Per_Share_Tables

Net Income Per Share (Tables)	12 Months Ended
	Dec. 31, 2013
Net Income Per Share [Abstract]	'
Computation of Basic and Diluted Net Income per Share	'
			2011		2012		2013
	Net income attributable to Qihoo 360 Technology Co. Ltd			15,603		46,746		99,652
	Accretion of Series A shares			203		-		-
	Accretion of Series B shares			313		-		-
	Accretion of Series C shares			255		-		-
	Undistributed earnings allocated to participating unvested shares (i)			1,124		2,049		3,175
	Net income attributable to Class A and Class B ordinary shareholders for computing basic net income per ordinary share			13,708		44,697		96,477
	Net income attributable to nonvested shareholders for computing basic net income per participating unvested shares (i)			1,124		2,049		3,175
	Accretion of Series A shares			203		-		-
	Net income attributable to Series A shareholders for computing basic net income per Series A share			203		-		-
	Accretion of Series B shares			313		-		-
	Net income attributable to Series B shareholders for computing basic net income per Series B share			313		-		-
	Accretion of Series C shares			255		-		-
	Net income attributable to Series C shareholders for computing basic net income per Series C share			255		-		-
	Weighted average ordinary shares outstanding used in computing basic net income per Class A and Class B ordinary share			137,775,752		168,709,221		174,727,288
	Weighted average shares used in calculating net income per participating unvested share-basic			11,292,535		7,733,645		5,749,393
	Weighted average shares outstanding used in computing basic net income per Series A share			8,356,247		-		-
	Weighted average shares outstanding used in computing basic net income per Series B share			9,755,085		-		-
	Weighted average shares outstanding used in computing basic net income per Series C share			2,057,209		-		-
	Effect of dilutive securities:
	Plus incremental weighted average ordinary shares from assumed exercise of stock options and nonvested shares using the treasury stock method (ii)			4,345,724		7,180,369		12,560,169
	Plus incremental weighted average ordinary shares from assumed conversion of preferred share using treasury stock method			19,578,504		-		-
	Weighted average ordinary shares outstanding used in computing diluted net income per Class A and Class B ordinary share (i)			172,992,515		183,623,235		193,036,850
	Net income per Class A and Class B ordinary share-basic			0.1		0.26		0.55
	Net income per participating unvested share-basic			0.1		0.26		0.55
	Net income per Series A share-basic			0.02		NA		NA
	Net income per Series B share-basic			0.03		NA		NA
	Net income per Series C share-basic			0.12		NA		NA
	Net income per Class A and Class B ordinary share-diluted			0.09		0.25		0.52
		(i)	The net income attributable to Qihoo 360 Technology Co. Ltd. was allocated among Class A and Class B ordinary shares (see Note 19), preferred shares (See Note 20) and certain nonvested shares (see Note 22) pro rata on the basis of their right to participate in dividends.
		(ii)	The calculation of the weighted average number of Class A and Class B ordinary shares for the purpose of diluted net income per share has considered the effect of certain potentially dilutive securities. For the year ended December 31, 2011, the incremental weighted average number of 19,578,504 and 4,345,724 ordinary shares from the assumed conversion of Series A, B and C preferred shares, and the exercise of share options and nonvested shares using the treasure stock method, respectively, has been included in the dilutive securities. For the years ended December 31, 2012 and 2013, the incremental weighted average number of 7,180,369 and 12,560,169 ordinary shares from the assumed exercise of share options and nonvested shares using the treasury stock method, respectively, has been included in the dilutive securities.

Sharebased_Compensation_Tables

Share-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2013
Share-based Compensation [Abstract]	'
Fair Value of Share Options, Valuation Assumptions	'
			Year ended December 31,
			2012			2013
	Risk-free interest rate			2.83% - 3.35%			3.40% - 4.02%
	Expected life (years)			6.35			6.35
	Volatility			46.98% - 74%			46.04% - 46.68%
	Dividend yield			-			-
Summary of Information Regarding Share Options at Grant Date	'
						Fair value per				Intrinsic value
						ordinary share		Exercise price		per option
	Grant date		Options granted			at the grant date		per option		at the grant date
	1-Jan-10			110,000		$	1.8	$	2.2		-
	1-Jul-10			5,039,000		$	2.58	$	2.8		-
	1-Jan-11			3,786,200		$	5.01	$	5.2		-
	14-Feb-11			700,000		$	6.6	$	5.2	$	981
	3-Mar-11			704,500		$	7.21	$	6	$	849
	1-Jul-11			2,689,200		$	14.09	$	12.94	$	3,102
	1-Jul-11			40,000		$	14.09	$	9.67	$	177
	1-Oct-11			375,000		$	10.89	$	10.89		-
	20-Jan-12			1,834,500		$	11.67	$	10.67	$	1,835
	10-Feb-12			935,000		$	11.17	$	11.35		-
	1-Mar-12			33,000		$	14	$	14.09		-
	15-Apr-12			171,500		$	14.52	$	14.52		-
	15-Jul-12			427,500		$	10.95	$	10.95		-
	15-Jul-12			40,000		$	10.95	$	10.67	$	11
	15-Oct-12			771,500		$	14.73	$	14.67	$	51
	15-Jan-13			701,500		$	20.55	$	21.09		-
	16-Jan-13			80,000		$	20.33	$	12.94	$	591
	15-Apr-13			406,000		$	19.92	$	20.11		-
	15-Jul-13			188,000		$	36.85	$	35.27	$	298
	15-Oct-13			145,500		$	57.03	$	55.38	$	240
	Total			19,177,900
Summary of Share Options Activities	'
						Weighted average
						exercise price
			Number of options			per option
	Outstanding at December 31, 2012			15,148,014			7.2
	Granted			1,521,000			25.4
	Exercised			(3,982,385	)		4.8
	Expired			(37,076	)		11.6
	Forfeited			(1,167,040	)		11.3
	Outstanding at December 31, 2013			11,482,513		$	10
	Vested and exercisable at December 31, 2013			3,840,705		$	5.5
	Vested and expect to vest at December 31, 2013			17,152,097		$	8.3
Schedule of Share Options Roll Forward	'
			Options outstanding									Options exercisable
						Weighted				Aggregate						Aggregate
						average				intrinsic						intrinsic
						remaining		Exercise		value as of				Exercise		value as of
			Number			contractual		price		December 31,		Number		price per		December 31,
			outstanding			term		per option		2013		exercisable		option		2013
	30-Jun-09			367,337			5.5 years	$	1.5	$	19,542		371,710	$	1.5	$	19,775
	1-Jan-10			50,854			6.0 years	$	2.2		2,670		33,354	$	2.2		1,751
	1-Jul-10			1,974,966			6.5 years	$	2.8		102,501		1,596,466	$	2.8		82,857
	1-Jan-11			2,422,833			7.0 years	$	5.2		119,930		795,683	$	5.2		39,386
	14-Feb-11			421,000			7.1 years	$	5.2		20,840		71,000	$	5.2		3,515
	3-Mar-11			277,659			7.2 years	$	6		13,522		80,409	$	6		3,916
	1-Jul-11			1,434,439			7.5 years	$	12.94		59,902		408,556	$	12.94		17,061
	1-Jul-11			40,000			7.5 years	$	9.67		1,801		16,000	$	9.67		721
	1-Oct-11			160,440			7.7 years	$	10.89		7,028		50,440	$	10.89		2,210
	January 20,2012			1,007,053			8.0 years	$	10.67		44,344		98,653	$	10.67		4,344
	10-Feb-12			698,002			8.1 years	$	11.35		30,261		122,003	$	11.35		5,289
	1-Mar-12			26,400			8.2 years	$	14.09		1,072		-	$	14.09		-
	15-Apr-12			110,057			8.3 years	$	14.52		4,422		14,057	$	14.52		565
	15-Jul-12			315,219			8.5 years	$	10.95		13,790		49,220	$	10.95		2,153
	15-Jul-12			40,000			8.5 years	$	10.67		1,761		8,000	$	10.67		352
	15-Oct-12			665,754			8.8 years	$	14.67		26,652		125,154	$	14.67		5,010
	15-Jan-13			693,500			9.0 years	$	21.09		23,311		-	$	21.09		-
	16-Jan-13			80,000			9.0 years	$	12.94		3,341		-	$	12.94		-
	15-Apr-13			366,000			9.3 years	$	20.11		12,659		-	$	20.11		-
	15-Jul-13			186,000			9.5 years	$	35.27		3,615		-	$	35.27		-
	15-Oct-13			145,000			9.8 years	$	55.38		-		-	$	55.38		-
	Total			11,482,513						$	512,964		3,840,705			$	188,905
Schedule of Nonvested Shares Granted	'
						Weighted average
						fair value per
			Number of			nonvested share
			nonvested shares			at the grant date(i)
	Outstanding at January 1, 2011			11,133,594
	Granted			3,255,976		$	7.76
	Vested			(5,824,709	)		1.28
	Forfeited			(380,610	)		1.58
	Outstanding at December 31, 2011			8,184,251
	Granted			4,845,877			12.03
	Vested			(3,136,471	)		2.32
	Forfeited			(1,121,419	)		7.34
	Outstanding at December 31, 2012			8,772,238		$	8.38
	Granted			5,148,971			32.02
	Vested			(3,038,327	)		23.55
	Forfeited			(812,088	)		13.92
	Outstanding at December 31, 2013			10,070,794		$	15.44
	Vested and to be transferred to grantees at December 31, 2013			18,416,568
	Vested and expect to vest at December 31, 2013			27,188,805
		(i)	The fair value of the underlying ordinary shares is the same as the fair value of the nonvested shares when calculating the weighted average fair value per nonvested share at the grant date.

Related_party_balances_and_tra1

Related party balances and transactions (Tables)	12 Months Ended
	Dec. 31, 2013
Related party balances and transactions [Abstract]	'
Related Parties and Relationship with Group	'
	Name of the related party		Relationship with the Group
	Related party F		The Group's cost method investee
	Related party G		Noncontrolling interest shareholder of one of the Group's subsidiaries
	Related party H		The Group's equity method investee
	Related party I		The Group's equity method investee
	Related party J		The Group's equity method investee
	Related party K		The Group's equity method investee
	Related party L		The Group's equity method investee
	Related party M		The Group's equity method investee
	Related party N		Chairman and Chief Executive Officer of the Company
	Related party O		Noncontrolling interest shareholder of one of the Group's subsidiaries
Amount Due from Related Parties	'
			December 31,
			2012				2013
	Related party H (i)		$	-			$	1,542
	Related party I (i)		$	-			$	496
	Related party J (ii)		$	-			$	627
	Related party L (iii)		$	-			$	206
			$	-			$	2,871
		(i)	The balances represent additional capital injection to equity method investees. As of December 31, 2013, the payments were made but the legal process has not been completed.
		(ii)	The balance mainly represents the receivable for the online marketing service provided to related party J.
		(iii)	It represents the unsecured interest-free bridge loans provided to related party L.
Amount Due to Related Parties	'
			December 31,
			2012				2013
	Related party G (iii)		$	148			$	-
	Related party K (i)		$	-			$	83
	Related party J (ii)		$	-			$	431
	Related party M (ii)		$	-			$	3
			$	148			$	517
		(i)	It represents the additional capital injection to be paid to related party K.
		(ii)	The balances represent the unpaid revenue sharing related to game operation.
		(iii)	It represents the pre-operating expenses paid by related party G on behalf of one of the Group's subsidiary, which has been settled in February 2013. The Group deconsolidated this subsidiary in September 2013.
Main Transactions with Related Parties	'
					For the year ended December 31,
	Nature		Company name		2011				2012		2013
	Marketing promotion received from		Related party F		$	56			$	-	$	-
	Online marketing promotion service fees received from		Related party J		$	-			$	-	$	387
	Revenue sharing related to game operation paid to		Related party J		$	-			$	-	$	199
	Revenue sharing related to game operation paid to		Related party M		$	-			$	-	$	266
	Purchase of shares from (i)		Related party N		$	-			$	-	$	1,989
	Disposal equity interest of a subsidiary (ii)		Related party O		$	-			$	4,207	$	-
		(i)	In July 2013, the Group acquired 51% equity interest of an overseas internet service company from three selling shareholders, one of which is related party N. The Company settled the consideration of $1,989 for 28.53% equity interest from related party N by issuance of 51,722 ordinary shares, equivalent to 34,481 ADSs, based upon the closing price of the Company's ADSs at the acquisition date. Please refer to note 3 (2) for detail of the transaction.
		(ii)	On January 10, 2012, the Group entered into a termination agreement with related party U. Pursuant to the termination agreement, the Group agreed to dispose its 53.5% equity interest in one of its former subsidiaries to related party O.

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies [Abstract]	'
Future Minimum Lease Payments under Operating Lease Agreements	'
	2014	$	8,712
	2015		3,218
	2016		1,591
	2017		743
	2018		702
		$	14,966
Future Minimum Lease Payments under Other Commitments	'
	2014	$	15,000
	2015		15,000
	2016		15,000
	2017		15,000
	2018		10,583
		$	70,583

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2013
Fair Value Measurements [Abstract]	'
Fair Value Measurements	'
		As of December 31, 2012								As of December 31, 2013
		Fair Value Measurements at the Reporting Date Using								Fair Value Measurements at the Reporting Date Using
		Quoted prices in		Significant						Quoted prices in		Significant
		active markets		other		Significant				active markets		other		Significant
		for identical		observable		unobservable				for identical		observable		unobservable
		instruments		inputs		inputs		Total		instruments		inputs		inputs		Total
		(level 1)		(level 2)		(level 3)		balance		(level 1)		(level 2)		(level 3)		balance
	Cash equivalents-term deposits	$	153,805	$	-	$	-	$	153,805	$	683,994	$	-	$	-	$	683,994
	Trading securities		179		-		-		179		253		-		-		253
	Total	$	153,984	$	-	$	-	$	153,984	$	684,247	$	-	$	-	$	684,247

Segments_and_geographic_inform1

Segments and geographic information (Tables)	12 Months Ended
	Dec. 31, 2013
Segments and geographic information [Abstract]	'
Segments and Geographic Information	'
		For the year ended December 31,
		2011		2012		2013
	Internet services
	Online advertising	$	123,048	$	221,488	$	417,133
	Internet value-added services		43,567		103,316		252,684
	Other services		346		4,078		1,271
	Sales of third party anti-virus software		890		150		-
	Total	$	167,851	$	329,032	$	671,088

Additional_Information_Financi1

Additional Information - Financial Statement Schedule I Condensed Financial Information of Parent Company (Tables)	12 Months Ended
	Dec. 31, 2013
Additional Information - Financial Statement Schedule I Condensed Financial Information of Parent Company [Abstract]	'
Condensed Financial Information of Parent Company Balance Sheets	'
		December 31,
		2012			2013
	ASSETS
	Current assets:
	Cash and cash equivalents	$	220,236		$	695,515
	Restricted cash		300			300
	Trading securities		179			253
	Prepaid expenses and other current assets		8,416			3,206
	Amounts due from subsidiaries and VIEs		29,805			167,395
	Deferred tax assets - current		195			306
	Total current assets		259,131			866,975
	Acquired intangible assets, net		3,923			2,449
	Investments in subsidiaries and VIEs		219,380			449,893
	Cost method investment		1,379			17,139
	Other non-current assets		-			11,707
	Deferred tax assets - noncurrent		440			383
	TOTAL ASSETS	$	484,253		$	1,348,546
	LIABILITIES
	Current liabilities:
	Accrued expenses and other current		2,470			6,760
	Deferred revenue-current		730			1,150
	Amounts due to subsidiaries and VIEs		1,316			2,306
	Total current liabilities		4,516			10,216
	Deferred revenue-noncurrent		1,641			1,437
	Long-term debt		-			600,000
	TOTAL LIABILITIES	$	6,157		$	611,653
	EQUITY
	Qihoo 360 Technology Co. Ltd. shareholders' equity
	Class A ordinary shares ($0.001 par value; 378,000,000 and 378,000,000 shares authorized as of December 31, 2012 and 2013, respectively; 123,472,524 and 134,123,218 shares issued and outstanding as of December 31, 2012 and 2013, respectively)		123			134
	Class B ordinary shares ($0.001 par value; 122,000,000 and 122,000,000 shares authorized as of December 31, 2012 and 2013, respectively; 60,684,573 and 54,767,703 shares issued and outstanding as of December 31, 2012 and 2013, respectively)		61			55
	Treasury stock		-			(139	)
	Additional paid-in capital		420,662			568,675
	Accumulated other comprehensive income		9,114			20,380
	Retained earnings		48,136			147,788
	Total shareholders' equity		478,096			736,893
	TOTAL EQUITY		478,096			736,893
	TOTAL LIABILITIES AND EQUITY	$	484,253		$	1,348,546
Condensed Financial Information of Parent Company Statements of Operations	'
		For the years ended December 31,
		2011			2012			2013
	Cost of revenues		16			4			-
	Operating expenses:
	Selling and marketing		31,473			21,289			15,519
	General and administrative		6,788			10,815			73,372
	Product development		12,283			21,782			38,211
	Total operating expenses		50,544			53,886			127,102
	Loss from operations		(50,560	)		(53,890	)		(127,102	)
	Interest income		1,662			4,702			6,341
	Interest expense		-			-			(5,551	)
	Other income		-			1,277			1,197
	Exchange  gain		6,514			412			5,100
	Impairment loss on long-term investments		(666	)		-			-
	Change in unrealized holding (loss) gain of trading securities		(220	)		(52	)		75
	Realized  gain from sales of trading securities		-			-			252
	Dividend income from a cost method investee		-			-			413
	Loss before income tax expense and earnings from subsidiary and VIEs		(43,270	)		(47,551	)		(119,275	)
	Income in earnings of subsidiaries and VIEs		58,873			94,639			219,247
	Income before income tax expense		15,603			47,088			99,972
	Income tax expense		-			(342	)		(320	)
	Net income attributable to Qihoo 360 Technology Co. Ltd.		15,603			46,746			99,652
	Accretion of Series A convertible participating redeemable preferred shares		203			-			-
	Accretion of Series B convertible participating redeemable preferred shares		313			-			-
	Accretion of Series C convertible participating redeemable preferred shares		255			-			-
	Net income attributable to ordinary shareholders of Qihoo 360 Technology Co. Ltd.	$	14,832		$	46,746		$	99,652
Condensed Financial Information of Parent Company Statements of Comprehensive Income	'
		For the years ended December 31,
		2011			2012			2013
	Net income	$	15,603		$	46,746		$	99,652
	Other comprehensive income, net of tax: Foreign currency translation adjustments		3,246			2,851			11,266
	Other comprehensive income		3,246			2,851			11,266
	Comprehensive income		18,849			49,597			110,918
	Add: Comprehensive loss attributable to noncontrolling interest		-			-			-
	Comprehensive income attributable to Qihoo 360 Technology Co. Ltd.	$	18,849		$	49,597		$	110,918
Condensed Financial Information of Parent Company Statements of Changes in Equity	'
																			Total
																			Qihoo 360
														Accumulated		(Accumulated			Technology
											Additional			other		deficit)			Co. Ltd.
		Ordinary shares									paid-in			comprehensive		retained			shareholders'
		Shares			Amount			Treasury Stock			capital			income		earnings			equity
	Balance as of January 1, 2011		71,560,740		$	72		$	-		$	12,568		$	3,017	$	(13,442	)	$	2,215
	Accretion of Series A convertible participating redeemable preferred shares		-			-			-			-			-		(203	)		(203	)
	Accretion of Series B convertible participating redeemable preferred shares		-			-			-			-			-		(313	)		(313	)
	Accretion of Series C convertible participating redeemable preferred shares		-			-			-			-			-		(255	)		(255	)
	Issuance of ordinary shares in connection with share-based compensation arrangements		3,059,779			3			-			-			-		-			3
	Share-based compensation		-			-			-			47,989			-		-			47,989
	Issuance of ordinary shares in connection with exercise of options		31,172			-			-			48			-		-			48
	Issuance of ordinary shares upon initial public offering ("IPO"), net of offering costs of $2,342		26,063,544			26			-			231,523			-		-			231,549
	Conversion of participating redeemable preferred shares to ordinary shares		78,314,016			78			-			70,893			-		-			70,971
	Net income		-			-			-			-			-		15,603			15,603
	Foreign currency translation adjustments		-			-			-			-			3,246		-			3,246
	Balance as of December 31, 2011		179,029,251			179			-			363,021			6,263		1,390			370,853
	Issuance of ordinary shares in connection with share-based compensation arrangements		3,512,394			3			-			-			-		-			3
	Share-based compensation		-			-			-			50,605			-		-			50,605
	Issuance of ordinary shares in connection with exercise of options		1,615,452			2			-			6,963			-		-			6,965
	Disposal of noncontrolling interest in subsidiaries		-			-			-			73			-		-			73
	Net income		-			-			-			-			-		46,746			46,746
	Foreign currency translation adjustments		-			-			-			-			2,851		-			2,851
	Balance as of December 31, 2012		184,157,097			184			-			420,662			9,114		48,136			478,096
	Issuance of ordinary shares in connection with share-based compensation arrangements		561,517			1			-			-			-		-			1
	Share repurchase		(14,544	)		-			(139	)		-			-		-			(139	)
	Share-based compensation		-			-			-			121,087			-		-			121,087
	Issuance of ordinary shares in connection with business acqusition		204,466			-			-			7,864			-		-			7,864
	Issuance of ordinary shares in connection with exercise of options		3,982,385			4			-			19,067			-		-			19,071
	Disposal of noncontrolling interest in subsidiaries		-			-			-			(5	)		-		-			-5
	Net income		-			-			-			-			-		99,652			99,652
	Foreign currency translation adjustments		-			-			-			-			11,266		-			11,266
	Balance as of December 31, 2013		188,890,921		$	189		$	(139	)	$	568,675		$	20,380	$	147,788		$	736,893
Condensed Financial Information of Parent Company Statements of Cash Flow	'
		For the years ended December 31,
		2011			2012			2013
	Cash flows from operating activities:
	Net income		15,603			46,746			99,652
	Adjustments to reconcile net income to net cash provided by operating activities:
	Share-based compensation		47,989			50,605			121,087
	Gain from investments in subsidiaries and VIEs		(58,873	)		(94,639	)		(219,247	)
	Depreciation and amortization		243			582			1,476
	Unrealized holding loss(gain) on trading securities		220			52			(75	)
	Realized gain from sales of trading securities		-			-			(252	)
	Dividend income from a cost method investee		-			-			(413	)
	Loss from impairment of long-term investments		666			-			-
	Prepaid expenses and other current assets		(352	)		(2,307	)		463
	Deferred taxes		(457	)		(178	)		(53	)
	Other noncurrent assets		-			-			743
	Accrued expenses and other current liabilities		92			149			5,488
	Deferred revenue		1,671			700			215
	Amount due from/to subsidiaries and VIEs		(20	)		(21,816	)		(128,738	)
	Net cash provided by (used in) operating activities		6,782			(20,106	)		(119,654	)
	Cash flows from investing activities:
	Restricted cash		-			(300	)		-
	Purchase of intangible assets		-			(1,500	)		(1,500	)
	Purchase of trading securities		(451	)		-			(510	)
	Capital contribution for cost method investments		(929	)		(450	)		(15,760	)
	Proceeds from sale of trading securities		-			-			762
	Dividends received from a cost method investee		-			-			413
	Investment in subsidiaries		(21,500	)		(1,200	)		-
	Net cash used in investing activities		(22,880	)		(3,450	)		(16,595	)
	Cash flows from financing activities:
	Proceeds from issuance of Convertible Senior Notes (net of issuance cost of $12,150)		-			-			587,850
	Proceeds from exercise of share options		20			2,089			23,678
	Proceeds from issuance of ordinary shares upon IPO		234,312			-			-
	Payment of IPO costs		(2,339	)		-			-
	Payment for share repurchase		-			(139	)		-
	Net cash provided by financing activities		231,993			1,950			611,528
	Net increase (decrease) in cash and cash equivalents		215,895			(21,606	)		475,279
	Cash and cash equivalents at beginning of year		25,947			241,842			220,236
	Cash and cash equivalents at end of year		241,842			220,236			695,515

Organization_and_Principal_Act2

Organization and Principal Activities (The VIE arrangements) (Details)	12 Months Ended
	Dec. 31, 2013
Business operation agreements [Member]	'
Variable Interest Entity [Line Items]	'
Term of power of attorney	'10 years
Technology consulting and services agreements [Member] | Maximum [Member]	'
Variable Interest Entity [Line Items]	'
Term of power of attorney	'10 years
Technology consulting and services agreements [Member] | Minimum [Member]	'
Variable Interest Entity [Line Items]	'
Term of power of attorney	'3 years
Equity disposition agreements [Member]	'
Variable Interest Entity [Line Items]	'
Term of power of attorney	'10 years
Loan agreements [Member]	'
Variable Interest Entity [Line Items]	'
Variable interest entity, ownership percentage	100.00%
Term of power of attorney	'10 years
Equity pledge agreements [Member]	'
Variable Interest Entity [Line Items]	'
Term of power of attorney	'10 years
Power of attorney [Member]	'
Variable Interest Entity [Line Items]	'
Term of power of attorney	'10 years

Organization_and_Principal_Act3

Organization and Principal Activities (Schedule of Variable Interest Entities) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Variable Interest Entity [Line Items]	'	'	'	'
Cash and cash equivalents	$1,013,465	$380,664	$343,731	$60,505
Restricted cash	2,368	1,905	'	'
Total current assets	1,157,717	435,272	'	'
Property and equipment, net	163,864	126,035	'	'
Acquired intangible assets, net	17,248	12,310	'	'
Other noncurrent assets	39,621	9,335	'	'
Total assets	1,568,896	689,529	'	'
Deferred revenue-current	46,632	21,049	'	'
Total current liabilities	208,598	203,714	'	'
Total liabilities	814,818	211,266	'	'
Revenues	671,088	329,032	167,851	'
Net income	97,849	46,471	14,544	'
Net cash provided by operating activities	210,226	117,788	82,303	'
Net cash used in investing activities	-196,874	-83,927	-34,811	'
Net cash provided by financing activities	613,498	1,986	233,280	'
Net increase in cash and cash equivalents	632,801	36,933	283,226	'
VIEs and their subsidiaries [Member]	'	'	'	'
Variable Interest Entity [Line Items]	'	'	'	'
Cash and cash equivalents	116,575	58,108	'	'
Restricted cash	2,068	1,605	'	'
Account receivable and other current assets	61,177	34,976	'	'
Total current assets	179,820	94,689	'	'
Property and equipment, net	91,861	57,275	'	'
Acquired intangible assets, net	9,681	5,113	'	'
Other noncurrent assets	37,778	26,814	'	'
Total noncurrent assets	139,320	89,202	'	'
Total assets	319,140	183,891	'	'
Deferred revenue-current	30,717	17,520	'	'
Account payable and other current liabilities	106,894	51,455	'	'
Total current liabilities	137,611	68,975	'	'
Total noncurrent liabilities	2,235	3,613	'	'
Total liabilities	139,846	72,588	'	'
Revenues	527,646	303,200	160,613	'
Net income	263,514	150,408	78,494	'
Net cash provided by operating activities	129,175	75,983	56,621	'
Net cash used in investing activities	-72,678	-50,951	-32,367	'
Net cash provided by financing activities	1,970	36	1,545	'
Net increase in cash and cash equivalents	$58,467	$25,068	$25,799	'

Organization_and_Principal_Act4

Organization and Principal Activities (Narrative) (Details) (VIEs and their subsidiaries [Member], USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
VIEs and their subsidiaries [Member]	'	'	'
Variable Interest Entity [Line Items]	'	'	'
Amount payable by the VIEs and their subsidiaries to WOFEs related to the service fees	$100,000	$2,300,000	$0
Percentage of consolidated revenues VIEs contribute	78.60%	92.10%	95.70%
Percentage of consolidated total assets VIEs accounted for	20.30%	26.70%	'
Percentage of consolidated total liabilities VIEs accounted for	17.20%	34.40%	'
Percentage of Group's employees hired by VIEs and their subsidiaries	33.00%	'	'

Summary_of_Significant_Account3

Summary of Significant Accounting Policies (Plant and Equipment, Estimated Useful Lives) (Details)	12 Months Ended
	Dec. 31, 2013
Computer equipment and application software [Member]	'
Property, Plant and Equipment [Line Items]	'
Estimated useful lives	'3 years
Building [Member]	'
Property, Plant and Equipment [Line Items]	'
Estimated useful lives	'44 - 60 years
Office building related facility and machines [Member]	'
Property, Plant and Equipment [Line Items]	'
Estimated useful lives	'10 - 15 years
Furniture and vehicles [Member]	'
Property, Plant and Equipment [Line Items]	'
Estimated useful lives	'3 - 5 years
Leasehold improvements [Member]	'
Property, Plant and Equipment [Line Items]	'
Estimated useful lives	'lesser of the lease term or the estimated useful life of the assets

Summary_of_Significant_Account4

Summary of Significant Accounting Policies (Acquired Intangible Assets, Estimated Useful Lives) (Details)	12 Months Ended
	Dec. 31, 2013
Domain names [Member] | Maximum [Member]	'
Acquired Definite-Lived Intangible Assets [Line Items]	'
Estimated useful lives (in years)	'10 years
Domain names [Member] | Minimum [Member]	'
Acquired Definite-Lived Intangible Assets [Line Items]	'
Estimated useful lives (in years)	'3 years
Source code [Member] | Maximum [Member]	'
Acquired Definite-Lived Intangible Assets [Line Items]	'
Estimated useful lives (in years)	'8 years
Source code [Member] | Minimum [Member]	'
Acquired Definite-Lived Intangible Assets [Line Items]	'
Estimated useful lives (in years)	'5 years
Technology [Member] | Maximum [Member]	'
Acquired Definite-Lived Intangible Assets [Line Items]	'
Estimated useful lives (in years)	'10 years
Technology [Member] | Minimum [Member]	'
Acquired Definite-Lived Intangible Assets [Line Items]	'
Estimated useful lives (in years)	'2 years
Non-compete agreement [Member] | Maximum [Member]	'
Acquired Definite-Lived Intangible Assets [Line Items]	'
Estimated useful lives (in years)	'5 years
Non-compete agreement [Member] | Minimum [Member]	'
Acquired Definite-Lived Intangible Assets [Line Items]	'
Estimated useful lives (in years)	'1 year
Trade mark [Member]	'
Acquired Definite-Lived Intangible Assets [Line Items]	'
Estimated useful lives (in years)	'3 years
Operating license [Member]	'
Acquired Definite-Lived Intangible Assets [Line Items]	'
Estimated useful lives (in years)	'8 years
Customer relationship [Member]	'
Acquired Definite-Lived Intangible Assets [Line Items]	'
Estimated useful lives (in years)	'3 years
User base [Member]	'
Acquired Definite-Lived Intangible Assets [Line Items]	'
Estimated useful lives (in years)	'1 year

Summary_of_Significant_Account5

Summary of Significant Accounting Policies (Concentration of Credit Risk) (Details)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
A [Member] | Total revenue [Member]	'		'	'
Concentration Risk [Line Items]	'		'	'
Concentration risk, percentage	0.00%	[1]	5.00%	10.00%
B [Member] | Total revenue [Member]	'		'	'
Concentration Risk [Line Items]	'		'	'
Concentration risk, percentage	0.00%	[1]	10.00%	11.00%
B [Member] | Accounts receivable [Member]	'		'	'
Concentration Risk [Line Items]	'		'	'
Concentration risk, percentage	32.00%		29.00%	'
C [Member] | Accounts receivable [Member]	'		'	'
Concentration Risk [Line Items]	'		'	'
Concentration risk, percentage	0.00%	[1]	12.00%	'
[1]	less than 10%

Summary_of_Significant_Account6

Summary of Significant Accounting Policies (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Summary of Significant Accounting Policies [Abstract]	'	'	'
Impairment loss on definite lived intangible assets	$107,000	$1,151,000	$87,000
Impairment loss on indefinite-lived intangible assets	841,000	197,000	0
Impairment loss on goodwill	0	0	0
Impairment loss on cost method investments	867,000	761,000	666,000
Significant influence existence criteria, minimum ownership interest	20.00%	'	'
Significant influence existence criteria, maximum ownership interest	50.00%	'	'
Impairment loss on equity method investments	4,137,000	1,541,000	236,000
Revenues from search referral service	0	'	'
Revenues derived from nonmonetary transactions	0	0	0
Business tax and related surcharges rate, Minimum	3.39%	'	'
Business tax and related surcharges rate, Maximum	8.70%	'	'
VAT and related surcharges rate, minimum	3.00%	'	'
VAT and related surcharges rate, maximum	19.04%	'	'
Business tax and VAT included in revenues and cost of revenues	39,909,000	18,434,000	9,078,000
Advertising cost	62,301,000	21,082,000	7,843,000
Subsidy income	$2,349,000	$2,570,000	$151,000
Minimum likelihood of uncertain being sustained for uncertain income tax position being recognized	50.00%	'	'

Acquisition_Narrative_Internet

Acquisition (Narrative, Internet Security Business) (Details) (USD $)	12 Months Ended			1 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Dec. 31, 2013	Apr. 30, 2012
				Internet service company with 80% equity interest owned by Group [Member]	Internet service company with 80% equity interest owned by Group [Member]	Internet service company with 80% equity interest owned by Group [Member]
Business Acquisition [Line Items]	'	'	'	'	'	'
Initial investment of 20% equity interests owned by Group	'	'	'	'	'	$1,983
Equity interest in acquiree immediately before the acquisition date, percentage	'	'	'	'	'	20.00%
Equity interest new acquired, step acquisition, percentage	'	'	'	60.00%	'	'
Cash consideration	'	'	'	7,966	'	'
Fair value of 20% equity interests owned by Group	'	'	'	1,831	'	'
Gain from equity method investments	'	'	'	120	'	'
Cash consideration, paid	'	'	'	'	7,966	'
Consolidated net revenue contributed by investee	'	'	'	'	119	'
Consolidated net loss contributed by investee	($99,652)	($46,746)	($15,603)	'	$1,333	'

Acquisition_Allocation_of_Purc

Acquisition (Allocation of Purchase Price, Internet Security Business) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013
In Thousands, unless otherwise specified				Internet service company with 80% equity interest owned by Group [Member]	Internet service company with 80% equity interest owned by Group [Member]	Internet service company with 80% equity interest owned by Group [Member]
					Trade mark [Member]	Technology [Member]
Business Acquisition [Line Items]	'	'	'	'	'	'
Cash	'	'	'	$387	'	'
Other net assets acquired, excluding intangible assets and related deferred tax liabilities	'	'	'	-9	'	'
Intangible assets	'	'	'	'	866	2,451
Deferred tax liability	'	'	'	-829	'	'
Goodwill	29,509	4,628	4,580	8,762	'	'
Fair value of 20% equity interests owned by Group	'	'	'	-1,831	'	'
Non-controlling interest	'	'	'	-1,831	'	'
Total	'	'	'	$7,966	'	'

Acquisition_Pro_Forma_Informat

Acquisition (Pro Forma Information, Internet Security Business) (Details) (Internet service company with 80% equity interest owned by Group [Member], USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Internet service company with 80% equity interest owned by Group [Member]	'	'
Business Acquisition [Line Items]	'	'
Pro forma revenue	$671,429	$329,591
Pro forma net income	$98,582	$45,938
Pro forma earnings per ordinary share-basic (in dollars per share)	$0.55	$0.26
Pro forma earnings per ordinary share-diluted (in dollars per share)	$0.51	$0.25

Acquisition_Narrative_Overseas

Acquisition (Narrative, Overseas Internet Service Business) (Details) (USD $)	12 Months Ended			1 Months Ended	12 Months Ended	1 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jul. 31, 2013	Dec. 31, 2013	Jul. 31, 2013
				Overseas internet service company [Member]	Overseas internet service company [Member]	Overseas internet service company [Member]
						Ordinary shares [Member]
Business Acquisition [Line Items]	'	'	'	'	'	'
Percentage of economic ownership acquired from three shareholders of acquiree	'	'	'	51.00%	'	'
Business acquisition, number of shares issued	'	'	'	'	'	204,466
Business acquisition, value of shares issued	'	'	'	'	'	$7,864
Consolidated net revenue contributed by investee	'	'	'	'	3,443	'
Consolidated net loss contributed by investee	($99,652)	($46,746)	($15,603)	'	$2,724	'

Acquisition_Allocation_of_Purc1

Acquisition (Allocation of Purchase Price, Overseas Internet Service Business) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jul. 31, 2013	Jul. 31, 2013	Jul. 31, 2013	Jul. 31, 2013
In Thousands, unless otherwise specified				Overseas internet service company [Member]	Overseas internet service company [Member]	Overseas internet service company [Member]	Overseas internet service company [Member]
					Customer relationship [Member]	Technology [Member]	User base [Member]
Business Acquisition [Line Items]	'	'	'	'	'	'	'
Cash	'	'	'	$687	'	'	'
Other net assets acquired, excluding intangible assets and related deferred tax liabilities	'	'	'	1,512	'	'	'
Intangible assets	'	'	'	'	3,147	535	129
Goodwill	29,509	4,628	4,580	8,319	'	'	'
Deferred tax liability	'	'	'	-1,069	'	'	'
Non-controlling interest	'	'	'	-5,396	'	'	'
Total	'	'	'	$7,864	'	'	'

Acquisition_Pro_Forma_Informat1

Acquisition (Pro Forma Information, Overseas Internet Service Business) (Details) (Overseas internet service company [Member], USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Overseas internet service company [Member]	'	'
Business Acquisition [Line Items]	'	'
Pro forma revenue	$675,981	$336,215
Pro forma net income	$99,001	$44,940
Pro forma earnings per ordinary share-basic (in dollars per share)	$0.55	$0.25
Pro forma earnings per ordinary share-diluted (in dollars per share)	$0.51	$0.24

Acquisition_Narrative_Internet1

Acquisition (Narrative, Internet Service Business) (Details) (USD $)	12 Months Ended			1 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Nov. 30, 2013	Dec. 31, 2013
				Internet service company with 51% equity interest owned by Group [Member]	Internet service company with 51% equity interest owned by Group [Member]
Business Acquisition [Line Items]	'	'	'	'	'
Percentage of economic ownership	'	'	'	51.00%	'
Cash consideration	'	'	'	$10,000	'
Consolidated net revenue contributed by investee	'	'	'	'	0
Consolidated net loss contributed by investee	($99,652)	($46,746)	($15,603)	'	$958

Acquisition_Allocation_of_Purc2

Acquisition (Allocation of Purchase Price, Internet Service Business) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Nov. 30, 2013	Nov. 30, 2013	Nov. 30, 2013
In Thousands, unless otherwise specified				Internet service company with 51% equity interest owned by Group [Member]	Internet service company with 51% equity interest owned by Group [Member]	Internet service company with 51% equity interest owned by Group [Member]
					Technology [Member]	User base [Member]
Business Acquisition [Line Items]	'	'	'	'	'	'
Cash	'	'	'	$10,169	'	'
Other net assets acquired, excluding intangible assets and related deferred tax liabilities	'	'	'	80	'	'
Intangible assets	'	'	'	'	1,188	27
Goodwill	29,509	4,628	4,580	6,346	'	'
Deferred tax liability	'	'	'	-304	'	'
Non-controlling interest	'	'	'	-7,506	'	'
Total	'	'	'	$10,000	'	'

Acquisition_Pro_Forma_Informat2

Acquisition (Pro Forma Information, Internet Service Business) (Details) (Internet service company with 51% equity interest owned by Group [Member], USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Internet service company with 51% equity interest owned by Group [Member]	'	'
Business Acquisition [Line Items]	'	'
Pro forma revenue	$671,180	$329,032
Pro forma net income	$97,658	$46,471
Pro forma earnings per ordinary share-basic (in dollars per share)	$0.54	$0.26
Pro forma earnings per ordinary share-diluted (in dollars per share)	$0.51	$0.25

Acquisition_Other_Acquisitions

Acquisition (Other Acquisitions) (Details) (USD $)

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Jun. 30, 2011

Dec. 31, 2011

Dec. 31, 2011

Jun. 30, 2011

Sep. 30, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

31-May-13

31-May-13

Dec. 31, 2013

In Thousands, unless otherwise specified

Internet service business acquired in 2011 [Member]

Internet service business acquired in 2011 [Member]

Anti-virus business acquired in 2011 [Member]

Anti-virus business acquired in 2011 [Member]

Software development business acquired in 2012 [Member]

Software development business acquired in 2012 [Member]

Software development business acquired in 2012 [Member]

Internet service business acquired in 2013 [Member]

Internet service business acquired in 2013 [Member]

Internet data center business ("Entity P") acquired in 2013 [Member]

Internet data center business ("Entity P") acquired in 2013 [Member]

Business Acquisition [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Equity interest new acquired, step acquisition, percentage

'

'

'

65.00%

'

'

'

65.00%

'

'

'

'

'

'

Cash consideration

'

'

'

$618

'

'

$491

$312

'

'

'

$1,790

$3,257

'

Goodwill

29,509

4,628

4,580

338

'

'

120

'

'

'

'

1,248

317

'

Cash consideration, paid

'

'

'

'

$618

$491

'

'

$127

$185

$1,790

'

'

$3,257

Percentage of economic ownership

'

'

'

'

'

'

'

'

'

'

'

'

51.00%

'

Disposal_of_a_Subsidiary_Detai

Disposal of a Subsidiary (Details) (USD $)	12 Months Ended			0 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jan. 10, 2012	Dec. 31, 2012	Sep. 30, 2013	Dec. 31, 2013
				One subsidiary of VIEs [Member]	One subsidiary of VIEs [Member]	One subsidiary of the Group [Member]	One subsidiary of the Group [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'	'	'	'	'
Percentage of disposed equity interest	'	'	'	53.50%	'	47.80%	'
Cash consideration of equity interest disposed	'	'	'	$4,207	'	'	'
Ownership percentage before selling equity share	'	'	'	'	'	77.80%	'
Gain (Loss) on disposal of subsidiaries	($1,144)	$3,566	$0	'	$3,566	'	($1,144)
Ownership percentage after selling equity share	'	'	'	'	'	30.00%	'

Restricted_Cash_Restricted_Cas

Restricted Cash (Restricted Cash Component) (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Restricted Cash [Abstract]	'		'
Deposits for registration of new subsidiaries of VIEs	$1,652	[1]	$1,605	[1]
Deposit used to secure for bank's acceptance bills in relation to payment for the construction of a building	416		0
Deposits used to secure for application of an operation right	300		300
Total	$2,368		$1,905
[1]	The balance represented the deposits placed in certain escrow accounts for registration of new VIEs' wholly owned subsidiaries.

Availableforsale_Investment_De

Available-for-sale Investment (Details) (USD $)	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Available-for-sale Investment [Abstract]	'	'	'
Convertible loan	$495	$495	$0

Accounts_Receivable_Schedule_o

Accounts Receivable (Schedule of Accounts Receivable) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
In Thousands, unless otherwise specified
Accounts receivable consists of:	'	'	'	'
Accounts receivable	$54,743	$23,804	'	'
Allowance for doubtful accounts	-145	-213	-68	-14
Accounts receivable, net	$54,598	$23,591	'	'

Accounts_Receivable_Movement_o

Accounts Receivable (Movement of allowance for doubtful accounts) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Movement of allowance for doubtful accounts	'	'	'
Balance at beginning of year	$213	$68	$14
Charge to expenses	157	154	51
Write offs during the year	-229	-10	0
Exchange rate differences	4	1	3
Balance at end of year	$145	$213	$68

Prepaid_expenses_and_other_cur2

Prepaid expenses and other current assets (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Prepaid expenses and other current assets [Abstract]	'		'
Guarantee loan to employees related to exercise of share options	$29,188	[1]	$753	[1]
Receivables of exercise cost share options	301	[2]	4,907	[2]
Prepaid principal for investments	10,534	[3]	1,003	[3]
Advance to suppliers	9,804		4,205
Deductible VAT Input	9,650		7,895
Prepaid marketing promotion fee	7,034		515
Interest receivable	3,219		1,086
Advance related to employees	2,146		1,011
Others	8,662		5,427
Total	$80,538		$26,802
[1]	Amount represents the individual income tax paid by the Group on behalf of employees associated with the options and nonvested shares granted by the Company. Such receivable is secured by share options or nonvested shares held by the employees, and will be repaid to the Company when the options are exercised and related ordinary shares are sold.
[2]	Amount represents the exercise cost to be received by the Group from a trading institution after the Group's employees exercised their stock options through such institution.
[3]	The Group made several payments to establish new companies with other independent third parties. The prepayments will be recorded as long-term investments when the investees are legally established.

Longterm_Investments_Details

Long-term Investments (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Cost method investments:	'		'
Less: impairment loss on long-term investments	($2,294)	[1]	($1,427)	[1]
Cost method investments, net	46,012		12,562
Equity method investments:	'		'
Less: impairment loss on long-term investments	-5,082	[2]	-1,541	[2]
Equity method investments, net	38,281		14,997
Total	84,293		27,559
Internet service company, Investee D [Member]	'		'
Cost method investments:	'		'
Cost method investments, gross	15,000	[3]	0	[3]
Internet security company, Investee E [Member]	'		'
Equity method investments:	'		'
Equity method investments, gross	24,099	[4]	1,761	[4]
Others [Member]	'		'
Cost method investments:	'		'
Cost method investments, gross	33,306		13,989
Equity method investments:	'		'
Equity method investments, gross	$19,264		$14,777
[1]	The Group reviews its cost method investments for impairment whenever an event or circumstance indicates that an other-than-temporary impairment has occurred. The Group considers available quantitative and qualitative evidence in evaluating potential impairment of its cost method investments. An impairment charge is recorded if the cost of an investment exceeds its fair value and such excess is determined to be other-than-temporary. The Group estimated the fair value of these investee companies based on discounted cash flow approach. Factors the Group considers in making such a determination include general market conditions, the duration and the extent to which the fair value of an investment is less than its cost, and the Group's intent and ability to hold such investment. As a result of the assessment process for its cost method investments, the Group recognized impairment charge of $666, $761 and $867 million in 2011, 2012 and 2013, respectively for certain cost method investments as their financial positions and performance of these investee companies are deteriorating and the Group does not expect them to generate any positive future cash flows. Accordingly, the Group estimated the fair values of these investee companies would be minimal.
[2]	An impairment charge is recorded if the carrying amount of the equity method investment exceeds its fair value and this condition is determined to be other-than-temporary. The Group estimated the fair value of these investee companies based on discounted cash flow approach which requires significant judgments, including the estimation of future cash flows, which is dependent on internal forecasts, the estimation of long term growth rate of a company's business, the estimation of the useful life over which cash flows will occur, and the determination of the weighted average cost of capital. Certain of the equity method investments experience a deteriorating financial position and performance and the Group does not expect them to generate any positive future cash flows. Accordingly, the Group accrued an impairment charge of $236, $1,541 and $4,137 in 2011, 2012 and 2013 on these equity method investments based on their fair value which would be minimal.
[3]	In December 2013, the Group invested in Investee D to purchase 4.13% of its ordinary shares for purchase prices of $15,000. The Group used the cost method of accounting to record these investments since the Group does not have the ability to exercise significant influence over the operating and financing activities. The management of the Group determined that there was no impairment on such investments during the year ended December 31, 2013.
[4]	In November 2011, the Group entered into a nonmonetary transaction with Investee E. The Group provides the license for using the Group's certain technology licenses to Investee E in exchange for its 30% equity interest in the form of preferred shares. The Group also needs to provide continuous technical support to the investee for ten years. Because the fair value of the licenses is more readily determinable, the Group recorded the transaction based on the fair value of the license which was valued with the assistance of a third-party valuation firm. The fair value was determined as $3,000. The transaction was accounted for as an equity method investment since the Group has the ability to exercise significant influence over the operating and financing activities of Investee E. The partial gain of the nonmonetary transaction was recorded as deferred revenue and is amortized ratably over the ten year contract period. In June 2012, the Group made an additional investment in Investee E for an aggregate price of $2,140 in cash to avoid diluting in its series B financing. In December 2013, the Group made another additional investment in Investee E for an aggregate price of $25,000 in cash in its series C financing. As of December 31, 2013, the Group held 40.8% equity interest in Investee E. The Group recognized $142, $2,337 and $2,661 share of loss in 2011, 2012 and 2013, respectively. The management of the Group determined that there was no impairment on such investment during the years ended December 31, 2011, 2012 and 2013.

Longterm_Investments_Narrative

Long-term Investments (Narrative) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	Investments	Investments
Long-term Investments [Abstract]	'	'	'
Cost method of accounting criteria, maximum ownership percentage	20.00%	'	'
Number of cost method investments fully disposed	2	'	'
Gain on disposal of cost-method investments	$427	$3,432	'
Number of cost method investments partially disposed	'	2	'
Equity method of accounting criteria, minimum ownership percentage	20.00%	'	'
Equity method of accounting criteria, maximum ownership percentage	50.00%	'	'
Loss on equity method investments	2,747	4,845	437
Number of equity method investments fully disposed	2	2	'
Number of equity method investments partially disposed	1	'	'
Gain on disposal of equity-method investments	15,380	1,334	'
Impairment loss on cost method investments	867	761	666
Impairment loss on equity method investments	$4,137	$1,541	$236

Longterm_Investments_Narrative1

Long-term Investments (Narrative, Investee D) (Details) (USD $)	12 Months Ended							1 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2013	Dec. 31, 2013
				Internet service company, Investee D [Member]		Internet service company, Investee D [Member]		Ordinary shares [Member]	Ordinary shares [Member]
								Internet service company, Investee D [Member]	Internet service company, Investee D [Member]
Schedule of Cost-method Investments [Line Items]	'	'	'	'		'		'	'
Ownership percentage	'	'	'	'		'		4.13%	'
Purchase price	'	'	'	$15,000	[1]	$0	[1]	$15,000	$15,000
Impairment on cost method investment	$867	$761	$666	'		'		'	$0
[1]	In December 2013, the Group invested in Investee D to purchase 4.13% of its ordinary shares for purchase prices of $15,000. The Group used the cost method of accounting to record these investments since the Group does not have the ability to exercise significant influence over the operating and financing activities. The management of the Group determined that there was no impairment on such investments during the year ended December 31, 2013.

Longterm_Investments_Narrative2

Long-term Investments (Narrative, Investee E) (Details) (USD $)	1 Months Ended			12 Months Ended
	Dec. 31, 2013	Jun. 30, 2012	Nov. 30, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Equity Method Investments [Line Items]	'	'	'	'	'	'
Loss on equity method investments	'	'	'	$2,747,000	$4,845,000	$437,000
Impairment on investment	'	'	'	4,137,000	1,541,000	236,000
Internet security company, Investee E [Member]	'	'	'	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'	'	'	'
Ownership percentage	40.80%	'	30.00%	40.80%	'	'
Continuous technical support for technology licenses, contract period (in years)	'	'	'10 years	'	'	'
Fair value of technology licenses	'	'	3,000,000	'	'	'
Equity method investment, additional investment	25,000,000	2,140,000	'	'	'	'
Loss on equity method investments	'	'	'	2,661,000	2,337,000	142,000
Impairment on investment	'	'	'	$0	$0	$0

Property_and_equipment_net_Det

Property and equipment, net (Details) (USD $)

12 Months Ended

1 Months Ended

12 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Aug. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Purchase of office buildings and associated land use rights in Chaoyang District [Member]

Computer equipment and application software [Member]

Computer equipment and application software [Member]

Building [Member]

Building [Member]

Building [Member]

Office building related facility and machines [Member]

Office building related facility and machines [Member]

Office building related facility and machines [Member]

Furniture and vehicles [Member]

Furniture and vehicles [Member]

Leasehold improvements [Member]

Leasehold improvements [Member]

Construction in Progress [Member]

Construction in Progress [Member]

SquareMeters

Purchase of office buildings and associated land use rights in Chaoyang District [Member]

Purchase of office buildings and associated land use rights in Chaoyang District [Member]

Property, Plant and Equipment [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Property, plant and equipment, gross

$221,865,000

$144,745,000

'

'

$149,877,000

$81,023,000

$46,471,000

[1]

$45,050,000

[1]

'

$14,022,000

[1]

$13,212,000

[1]

'

$4,672,000

$4,422,000

$1,354,000

$1,038,000

$5,469,000

[2]

$0

[2]

Less: Accumulated depreciation and amortization

58,001,000

18,710,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Property and equipment, net

163,864,000

126,035,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Area of associated land use rights

'

'

'

69,205

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash consideration of office building and land use rights

'

'

'

222,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Capitalized cost

'

'

'

'

'

'

'

'

43,927,000

'

'

13,212,000

'

'

'

'

'

'

Depreciation and amortization expenses

$38,453,000

$14,768,000

$3,393,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

[1]

In August 2012, the Group entered into a series of definitive agreements to purchase two parcels of office buildings and the associated land use rights with an area of approximately 69,205 square meters in Chaoyang District, Beijing, China for a total cash consideration of $222 million. The Group completed the acquisition of one parcel of the buildings in 2012 and the acquisition of the other parcel of buildings was in process as of December 31, 2013. The Group capitalized the related building cost of $43,927 and the cost for the facilities of the first parcel of building of $13,212 in the year ended December 31, 2012. No building cost and facilities cost were capitalized in year 2013.

[2]

As part of the acquisition of Entity P in 2013 as described in Note 3(4), the Group acquired a building under construction at Henan Province of China.

Land_Use_Rights_Net_Details

Land Use Rights, Net (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	31-May-13
Land Use Rights, Net [Abstract]	'	'	'
Land use rights	$77,590	$73,785	'
Less: accumulated depreciation and amortization	1,892	140	'
Land use rights, net	75,698	73,645	'
Land use rights of in Henan Province in connection with acquisition of entity P	'	'	1,632
Land use rights, amortization expenses	1,714	140	'
Land use rights, future amortization expense per year in next five years	$1,760	'	'

Acquired_Intangible_Assets_Net2

Acquired Intangible Assets, Net (Definite-lived intangible assets) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Acquired Definite-Lived Intangible Assets [Line Items]	'	'
Definite-lived, intangible assets	$25,119	$15,799
Less: Accumulated amortization	-7,722	-3,417
Less: Impairment loss	-1,383	-1,242
Acquired definite-lived intangible assets, net	16,014	11,140
Domain names [Member]	'	'
Acquired Definite-Lived Intangible Assets [Line Items]	'	'
Definite-lived, intangible assets	2,482	2,426
Less: Accumulated amortization	-859	-423
Less: Impairment loss	-424	-411
Source code [Member]	'	'
Acquired Definite-Lived Intangible Assets [Line Items]	'	'
Definite-lived, intangible assets	1,662	1,754
Less: Accumulated amortization	-1,050	-821
Less: Impairment loss	-72	-158
Technology [Member]	'	'
Acquired Definite-Lived Intangible Assets [Line Items]	'	'
Definite-lived, intangible assets	12,013	6,999
Less: Accumulated amortization	-3,450	-1,872
Less: Impairment loss	-887	-673
Non-compete agreement [Member]	'	'
Acquired Definite-Lived Intangible Assets [Line Items]	'	'
Definite-lived, intangible assets	3,985	3,933
Less: Accumulated amortization	-1,584	-299
Operating License [Member]	'	'
Acquired Definite-Lived Intangible Assets [Line Items]	'	'
Definite-lived, intangible assets	1,768	610
Less: Accumulated amortization	-29	-2
Trademarks [Member]	'	'
Acquired Definite-Lived Intangible Assets [Line Items]	'	'
Definite-lived, intangible assets	79	77
Less: Accumulated amortization	-235	0
User base [Member]	'	'
Acquired Definite-Lived Intangible Assets [Line Items]	'	'
Definite-lived, intangible assets	157	0
Less: Accumulated amortization	-8	0
Customer relationship [Member]	'	'
Acquired Definite-Lived Intangible Assets [Line Items]	'	'
Definite-lived, intangible assets	2,973	0
Less: Accumulated amortization	($507)	$0

Acquired_Intangible_Assets_Net3

Acquired Intangible Assets, Net (Definite-lived intangible assets) (Narrative) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Acquired Intangible Assets, Net [Abstract]	'	'	'
Amortization expenses for intangible assets	$4,176	$1,689	$834
Expected Amortization Expense for Intangible Assets:	'	'	'
2014	5,075	'	'
2015	4,484	'	'
2016	1,826	'	'
2017	1,211	'	'
2018 and after	3,418	'	'
Impairment loss on definite lived intangible assets	$107	$1,151	$87

Acquired_Intangible_Assets_Net4

Acquired Intangible Assets, Net (Indefinite-lived intangible assets) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Acquired Indefinite-lived Intangible Assets [Line Items]	'	'	'
Indefinite-lived, intangible assets	$2,571,000	$1,648,000	'
Less: Impairment loss	-1,337,000	-478,000	'
Acquired intangible assets, net	1,234,000	1,170,000	'
Impairment loss on indefinite-lived intangible assets	841,000	197,000	0
Domain names [Member]	'	'	'
Acquired Indefinite-lived Intangible Assets [Line Items]	'	'	'
Indefinite-lived, intangible assets	371,000	360,000	'
Less: Impairment loss	-288,000	-281,000	'
Trademarks [Member]	'	'	'
Acquired Indefinite-lived Intangible Assets [Line Items]	'	'	'
Indefinite-lived, intangible assets	2,200,000	1,288,000	'
Less: Impairment loss	($1,049,000)	($197,000)	'

Goodwill_Details

Goodwill (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill [Abstract]	'	'	'
Beginning balance	$4,628,000	$4,580,000	'
Goodwill acquired in acquisitions of business	24,992,000	0	'
Exchange rate differences	-111,000	48,000	'
Ending balance	29,509,000	4,628,000	4,580,000
Goodwill, Impairment Loss	$0	$0	$0

Accrued_expenses_and_other_cur2

Accrued expenses and other current liabilities (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Accrued expenses and other current liabilities [Abstract]	'	'
Payable for purchasing plant, property and equipment	$20,419	$59,703
Payable for purchasing intangible assets	442	3,340
Payable for purchasing land use rights	0	62,717
Payroll related payable	19,217	13,446
Accrued agent rebates and profit sharing cost	16,891	1,723
Accrued marketing promotion expenses	13,965	6,102
Other tax payable	12,094	2,616
Deposits from advertising customers	10,060	1,376
Accrued bandwidth	8,566	9,052
Accrued professional service fee	6,640	3,145
Accrued interest expenses of convertible senior notes (see note 17)	4,808	0
Other current liabilities	7,316	5,326
Total	$120,418	$168,546

Deferred_Revenue_Details

Deferred Revenue (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Deferred Revenue Arrangement [Line Items]	'		'
Deferred revenue-current	$46,632		$21,049
Deferred revenue-noncurrent	3,544		6,762
Deferred revenue from customers [Member]	'		'
Deferred Revenue Arrangement [Line Items]	'		'
Deferred revenue-current	31,503	[1]	14,915	[1]
Deferred revenue for system development services [Member]	'		'
Deferred Revenue Arrangement [Line Items]	'		'
Deferred revenue-current	2,266	[2]	1,102	[2]
Deferred revenue-noncurrent	168	[2]	408	[2]
Deferred subsidy income [Member]	'		'
Deferred Revenue Arrangement [Line Items]	'		'
Deferred revenue-current	11,503	[3]	4,093	[3]
Deferred revenue-noncurrent	495	[3]	3,059	[3]
Deferred license fee [Member]	'		'
Deferred Revenue Arrangement [Line Items]	'		'
Deferred revenue-current	210	[4]	210	[4]
Deferred revenue-noncurrent	1,444	[4]	1,654	[4]
Deferred reimbursement of ADS depositary service [Member]	'		'
Deferred Revenue Arrangement [Line Items]	'		'
Deferred revenue-current	1,150	[5]	729	[5]
Deferred revenue-noncurrent	$1,437	[5]	$1,641	[5]
[1]	Deferred revenue from customers mainly represents payments received from (1) advertising customers before the services were provided by the Group; and (2) game players before the in-game currency were consumed.
[2]	Deferred revenue for system development services represents payments received from third party customers in relation to the service to be provided by the Group which is subject to the customers' inspection and acceptance.
[3]	The Group received subsidies from the local government for web-security related research and development projects. The amount was deferred since the projects are subject to final inspection upon the completion.
[4]	Deferred license fee was related to the nonmonetary transaction as described in Note 9(ii).
[5]	Deferred reimbursement of ADS depositary service represents the cash received from the Bank of New York Mellon as reimbursement of its ADS depositary service, which will be recognized ratably over the ADS contract term.

ShortTerm_Loan_Details

Short-Term Loan (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Short-term Loan [Line Items]	'	'
Short-term loans	$1,322	$0
Interest rate, per annum	7.80%	'
Maturity term	'12 months	'
Entity P [Member]	'	'
Short-term Loan [Line Items]	'	'
Land use rights, guarantee for short-term loan	$1,632	'

Longterm_Debt_Narrative_Detail

Long-term Debt (Narrative) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Sep. 05, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Sep. 05, 2013
In Thousands, except Per Share data, unless otherwise specified			Convertible Senior Notes [Member]	Convertible Senior Notes [Member]	Convertible Senior Notes [Member]	Convertible Senior Notes [Member]	Convertible Senior Notes [Member]	Convertible Senior Notes [Member]
					September 15, 2016 [Member]	September 5, 2013 [Member]	On or after September 15, 2016 (after year 3) [Member]	ADS [Member]
Long-term debt [Line Items]	'	'	'	'	'	'	'	'
Convertible Senior Notes	$600,000	$0	$600,000	$600,000	'	'	'	'
Annual rate	'	'	2.50%	'	'	'	'	'
Initial conversion rate per $1 principal amount of the Notes	'	'	'	'	'	'	'	9.0119
Initial conversion price	'	'	'	'	'	'	'	$110.96
Issuance cost	'	'	12,450	'	'	'	'	'
Proceeds from issuance of the Notes	'	'	$587,850	'	'	'	'	'
Redemption period, start date	'	'	'	'	15-Sep-16	5-Sep-13	15-Sep-16	'
Redemption period, end date	'	'	'	'	15-Sep-18	15-Sep-18	15-Sep-18	'
Redemption price, percentage of principal amount redeemed	'	'	'	'	100.00%	100.00%	100.00%	'
Redemption, description	'	'	'	'	'	'	'On or after September 15, 2016 (three years after the date of issuance of the Notes), the Company may redeem any or all of the Notes in cash at the redemption price, provided that the last reported sale price of the Company's ADSs for 20 or more trading days in a period of 30 consecutive trading days ending within 10 trading days immediately prior to the date of the redemption notice exceeds 130% of the applicable conversion price in effect on each such trading day.	'

Longterm_Debt_Interest_Expense

Long-term Debt (Interest Expense of Long-term Debt ) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument [Line Items]	'	'	'
Total interest expense	$5,572	$0	$53
Convertible Senior Notes [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Interest expense at an annual rate of 2.50%	4,808	'	'
Amortization of debt issuance costs	743	'	'
Total interest expense	$5,551	'	'

Income_Taxes_Narrative_Details

Income Taxes (Narrative) (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Corporate Income Tax Rate [Line Items]	'	'	'
Aggregate undistributed earnings available for distribution to the Company	$354,996	'	'
Income tax expense increased without tax holidays	43,460	17,844	7,036
Positive impact of tax holidays on basic net income per ordinary share	$0.05	$0.01	$0.24
Hong Kong [Member] | Subsidiaries [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Unified income tax rate	16.50%	16.50%	16.50%
Singapore [Member] | Subsidiaries [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Unified income tax rate	17.00%	'	'
Japan [Member] | Subsidiaries [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Unified income tax rate	25.50%	'	'
Income tax, percentage of surcharge	2.55%	'	'
Withholding taxes rate on remittance of dividends	20.00%	'	'
Preferential withholding taxes rate on remittance of dividends	10.00%	'	'
United States of America ("USA") [Member] | Subsidiaries [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Withholding taxes rate on remittance of dividends	30.00%	'	'
United States of America ("USA") [Member] | Subsidiaries [Member] | Minimum [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Unified income tax rate	15.00%	'	'
United States of America ("USA") [Member] | Subsidiaries [Member] | Maximum [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Unified income tax rate	39.00%	'	'
Delaware [Member] | Subsidiaries [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
State income tax rate in Delaware	8.70%	'	'
PRC [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Unified income tax rate	25.00%	25.00%	25.00%
Income tax rate under deemed-profit method	2.50%	'	'
Income tax expense increased without tax holidays	43,460	17,844	7,036
PRC [Member] | Subsidiaries [Member] | Pro Forma [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Withholding taxes rate on remittance of dividends	10.00%	'	'
PRC [Member] | HNTE [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Preferential tax rate	15.00%	'	'
PRC [Member] | Qizhi Software [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Preferential tax rate	15.00%	15.00%	15.00%
PRC [Member] | Beijing Qihu [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Preferential tax rate	15.00%	15.00%	15.00%
PRC [Member] | Beijing Star World [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Preferential tax rate	15.00%	15.00%	15.00%
PRC [Member] | Software Enterprise [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Preferential tax rate	12.50%	'	'
Income tax holiday, exemption period as Software Enterprise	'2 years	'	'
Income taxes reduction percentage	50.00%	'	'
Income tax holiday, half rate period as Software Enterprise	'3 years	'	'
PRC [Member] | Tianjin Qisi [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Income tax holiday, exemption period as Software Enterprise	'2 years	'	'
Income tax holiday, half rate period as Software Enterprise	'3 years	'	'
PRC [Member] | Other VIEs and VIEs' subsidiaries [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Unified income tax rate	25.00%	'	'
PRC [Member] | The Company and its subsidiaries, VIEs and VIEs' subsidiaries registered outside the PRC [Member] | Pro Forma [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Unified income tax rate	25.00%	'	'
PRC [Member] | Subsidiaries and VIEs [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Total net operating loss carry forwards	$18,496	'	'

Income_Taxes_Components_of_Inc

Income Taxes (Components of Income Tax Expense) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Components of Income Tax Expense:	'	'	'
Current income tax expense	$22,382	$12,062	$10,724
Deferred income tax expense (benefit)	1,041	-683	150
Total income tax expense	$23,423	$11,379	$10,874

Income_Taxes_Components_of_Def

Income Taxes (Components of Deferred Tax Assets and Liabilities) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current deferred tax assets:	'	'
Accrued payroll	$2,889	$1,950
Provision of allowance for doubtful accounts	92	125
Deferred revenue-current	306	196
Less: Valuation allowance	-158	-140
Current deferred tax assets, net	3,129	2,131
Noncurrent deferred tax assets:	'	'
Deferred revenue-noncurrent	383	440
Acquired intangible assets	266	175
Fixed assets	66	0
Subsidy income	231	130
Net operating loss carry forwards	4,592	975
Less: Valuation allowance	-4,592	-975
Noncurrent deferred tax assets, net	946	745
Noncurrent deferred tax liabilities:	'	'
Acquired intangible assets	2,676	425
Subsidy income	0	365
Noncurrent deferred tax liabilities	$2,676	$790

Income_Taxes_Effective_Income_

Income Taxes (Effective Income Tax Rate Reconciliation) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Corporate Income Tax Rate [Line Items]	'	'	'
Income before income tax expense	$124,019,000	$62,695,000	$25,855,000
Income tax expense at statutory income tax rate	31,005,000	15,674,000	6,464,000
Permanent differences	1,663,000	870,000	116,000
Effect of different income tax calculation method required by tax bureau	48,000	67,000	-84,000
Effect of income tax holiday and preferential tax rates	-43,460,000	-17,844,000	-7,036,000
Changes in valuation allowance	3,758,000	420,000	829,000
Total income tax expense	23,423,000	11,379,000	10,874,000
PRC [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
PRC statutory income tax rate (in percentage)	25.00%	25.00%	25.00%
Effect of income tax holiday and preferential tax rates	-43,460,000	-17,844,000	-7,036,000
Cayman Islands [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Effect of tax exempt status	30,272,000	12,217,000	10,818,000
Hong Kong [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Effect of different income tax rate in Hong Kong	168,000	-25,000	-233,000
Other jurisdictions [Member]	'	'	'
Corporate Income Tax Rate [Line Items]	'	'	'
Effect of tax exempt status	($31,000)	$0	$0

Ordinary_shares_Details

Ordinary shares (Details) (USD $)

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Jul. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Apr. 04, 2011

Dec. 31, 2013

Dec. 31, 2012

Apr. 04, 2011

Dec. 31, 2013

Dec. 31, 2012

Sep. 30, 2013

Jun. 30, 2013

Dec. 31, 2012

Sep. 30, 2012

Mar. 31, 2012

Dec. 31, 2011

Sep. 30, 2011

Aug. 31, 2012

Jul. 31, 2012

Jan. 31, 2012

In Millions, except Share data, unless otherwise specified

Overseas internet service company [Member]

A related party of the Company [Member]

Selling shareholder two [Member]

Selling shareholder three [Member]

Common Class A [Member]

Common Class A [Member]

Common Class A [Member]

Common Class B [Member]

Common Class B [Member]

Common Class B [Member]

Ordinary shares [Member]

Ordinary shares [Member]

Ordinary shares [Member]

Ordinary shares [Member]

Ordinary shares [Member]

Ordinary shares [Member]

Ordinary shares [Member]

ADS [Member]

ADS [Member]

ADS [Member]

Schedule of Ordinary shares [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Ordinary shares, shares authorized

500,000,000

500,000,000

500,000,000

'

'

'

'

'

378,000,000

378,000,000

'

122,000,000

122,000,000

'

'

'

'

'

'

'

'

'

'

Ordinary shares, par value

$0.00

$0.00

$0.00

'

'

'

'

'

$0.00

$0.00

'

$0.00

$0.00

'

'

'

'

'

'

'

'

'

'

Ordinary shares, shares issued

'

'

'

'

'

'

'

26,063,544

'

'

'

'

'

2,498,022

2,045,880

2,403,180

2,160,951

563,715

907,086

2,152,693

'

'

'

Ordinary shares, shares issued, offered through IPO

'

'

'

'

'

'

'

20,891,130

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Ordinary shares, shares issued in connection with concurrent private placement

'

'

'

'

'

'

'

5,172,414

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Conversion of stock, shares issued

'

'

'

'

'

'

'

27,024,089

'

'

51,289,927

'

'

'

'

'

'

'

'

'

'

'

'

Stock repurchase program, authorized amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$50

Stock repurchase program, number of shares repurchased during period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

8,796

900

'

Stock repurchase program, repurchase price

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$14.31

$14.50

'

Issuance of ordinary shares in connection with business acquisitions, shares (in shares)

'

'

'

'

51,722

76,372

76,372

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of equity interest in acquisition

'

'

'

51.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Ordinary shares, shares outstanding

'

'

'

'

'

'

'

'

134,123,218

134,123,218

'

54,767,703

54,767,703

'

'

'

'

'

'

'

'

'

'

Convertible_Participating_Rede1

Convertible Participating Redeemable Preferred Shares (Details) (USD $)

12 Months Ended

1 Months Ended

5 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

In Thousands, except Share data, unless otherwise specified

Dec. 31, 2013

Apr. 30, 2010

31-May-06

31-May-06

Dec. 31, 2013

Dec. 31, 2011

Nov. 30, 2006

Dec. 31, 2013

Dec. 31, 2011

Jan. 31, 2010

Dec. 31, 2013

Dec. 31, 2011

Dec. 31, 2013

Apr. 04, 2011

Apr. 04, 2011

Dec. 31, 2013

Directors

Series A Preferred Stock [Member]

Series A Preferred Stock [Member]

Series A Preferred Stock [Member]

Series A Preferred Stock [Member]

Series A Preferred Stock [Member]

Series B Preferred Stock [Member]

Series B Preferred Stock [Member]

Series B Preferred Stock [Member]

Series C Preferred Stock [Member]

Series C Preferred Stock [Member]

Series C Preferred Stock [Member]

Series A and B Preferred Stock [Member]

Common Class A [Member]

Common Class B [Member]

Ordinary shares [Member]

Observers

Observers

Observers

Directors

Directors

Directors

Temporary Equity [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Convertible participating redeemable preferred shares, shares issued

'

'

'

31,003,440

'

'

37,878,789

'

'

7,831,467

'

'

'

'

'

'

Convertible participating redeemable preferred shares, subscription price

'

'

'

$0.50

'

'

$0.66

'

'

$2.55

'

'

'

'

'

'

Proceeds from issuance of convertible preferred stock

'

'

'

$15,500

'

'

$25,000

'

'

$20,000

'

'

'

'

'

'

Warrants granted

'

'

1,600,320

'

'

'

'

'

'

'

'

'

'

'

'

'

Warrants exercisable, subscription amount

'

'

800

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares transferred between shareholders, value per share

'

$2.55

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares transferred between shareholders, shares

'

1,691,610

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares transferred to shareholders of more than one class of shares

'

156,631

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Conversion of participating redeemable preferred shares to ordinary shares, shares (in shares)

'

'

'

'

'

'

'

'

'

'

'

'

'

27,024,089

51,289,927

'

Convertible participating redeemable preferred shares, redemption terms

'

'

'

'

'

'

'

'

'

'

'At any time commencing on the fifth anniversary of the series C subscription date, if holders of at least 66 2/3% of the series C shares approve redemption, any holder of series C shares shall be entitled to require the Company, by serving a Redemption Notice on the Company, to redeem, out of legally available funds, for all, but not less than all, of the series C shares held by such holder, provided, that the Group Companies remain solvent and have sufficient cash for working capital required for at least one year by reference to the annual budget approved by the Board of Directors.

'

'At any time commencing on the earlier of (a) such time as the Company's CEO is enjoined or prevented from serving as the CEO of the Company and (b) the sixth anniversary of the Series B Subscription Date, (i) if holders of at least 66 2/3% of the Series B shares approve redemption, any holder of Series B share shall be entitled to require the Company and (ii) if holders of at least 75% of the Series A shares approve redemption, any holder of Series A shares shall be entitled to require the Company, in each case by a six-month prior notice in writing to the Company to redeem, out of legally available funds, for all, but not less than all, of the Series B shares or Series A shares held by such holder, as applicable; provided the Group remain solvent and have sufficient cash for working capital required for at least one year, by reference to the annual budget approved by the Board. This redemption right set forth herein shall terminate upon closing of a qualified initial public offering ("Qualified IPO").

'

'

'

Convertible participating redeemable preferred shares, definition of qualified IPO

'Qualified IPO means firm commitment underwritten public offering either with total offering proceeds to the Company of at least $80,000 before deduction of the underwriting commissions and expenses or with the approval of holders of 66 2/3% or more of the then issued and outstanding preferred shares of the Company.

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Convertible participating redeemable preferred shares, percentage of unpaid dividends for redemption payment

'

'

'

'

5.00%

'

'

5.00%

'

'

5.00%

'

'

'

'

'

Accretion of convertible participating redeemable preferred shares

'

'

'

'

'

$203

'

'

$313

'

'

$255

'

'

'

'

Convertible participating redeemable preferred shares, automatic conversion terms

'

'

'

'

'Immediately upon closing of a Qualified IPO or approval of the holder of at least 75% of the Series A shares, each outstanding share of Series A shares shall be automatically converted, into the number of fully paid and ordinary shares in accordance with the then effective applicable conversion price.

'

'

'Immediately upon closing of a Qualified IPO, each outstanding share of Series B shares shall be automatically converted, into the number of fully paid and ordinary shares in accordance with the then effective applicable conversion price.

'

'

'Immediately upon closing of a Qualified IPO or approval of the holder of at least 75% of the Series C preferred shares, each outstanding share of Series C shares shall be automatically converted, into the number of fully paid ordinary shares in accordance with the then effective applicable conversion price.

'

'

'

'

'

Maximum number of directors in board of directors

6

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3

Number of directors represent preferred shareholders in board of directors

'

'

'

'

2

'

'

1

'

'

'

'

'

'

'

'

Number of non-voting observers preferred shareholders entitled in board of directors

'

'

'

'

3

'

'

2

'

'

1

'

'

'

'

'

Net_Income_Per_Share_Details

Net Income Per Share (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Schedule of Computation of basic and diluted net income per share [Line Items]	'		'		'
Net income attributable to Qihoo 360 Technology Co. Ltd	$99,652		$46,746		$15,603
Weighted average shares outstanding used in computing basic net income per share	180,476,681		176,442,866		149,068,287
Weighted average shares outstanding used in computing diluted net income per share	193,036,850		183,623,235		172,992,515
Effect of dilutive securities:	'		'		'
Plus incremental weighted average ordinary shares from assumed exercise of stock options and nonvested shares using the treasury stock method	12,560,169	[1]	7,180,369	[1]	4,345,724	[1]
Plus incremental weighted average ordinary shares from assumed conversion of preferred share using treasury stock method	0		0		19,578,504
Net income per Share, basic	$0.55		$0.26		$0.10
Net income per Share, diluted	$0.52		$0.25		$0.09
Class A and Class B ordinary shares [Member]	'		'		'
Schedule of Computation of basic and diluted net income per share [Line Items]	'		'		'
Net income attributable to Qihoo 360 Technology Co. Ltd	96,477		44,697		13,708
Weighted average shares outstanding used in computing basic net income per share	174,727,288		168,709,221		137,775,752
Weighted average shares outstanding used in computing diluted net income per share	193,036,850	[2]	183,623,235	[2]	172,992,515	[2]
Effect of dilutive securities:	'		'		'
Net income per Share, basic	$0.55		$0.26		$0.10
Net income per Share, diluted	$0.52		$0.25		$0.09
Series A Preferred Stock [Member]	'		'		'
Schedule of Computation of basic and diluted net income per share [Line Items]	'		'		'
Net income attributable to Qihoo 360 Technology Co. Ltd	'		'		203
Accretion of convertible participating redeemable preferred shares	'		'		203
Weighted average shares outstanding used in computing basic net income per share	0		0		8,356,247
Effect of dilutive securities:	'		'		'
Net income per Share, basic	'		'		$0.02
Series B Preferred Stock [Member]	'		'		'
Schedule of Computation of basic and diluted net income per share [Line Items]	'		'		'
Net income attributable to Qihoo 360 Technology Co. Ltd	'		'		313
Accretion of convertible participating redeemable preferred shares	'		'		313
Weighted average shares outstanding used in computing basic net income per share	0		0		9,755,085
Effect of dilutive securities:	'		'		'
Net income per Share, basic	'		'		$0.03
Series C Preferred Stock [Member]	'		'		'
Schedule of Computation of basic and diluted net income per share [Line Items]	'		'		'
Net income attributable to Qihoo 360 Technology Co. Ltd	'		'		255
Accretion of convertible participating redeemable preferred shares	'		'		255
Weighted average shares outstanding used in computing basic net income per share	0		0		2,057,209
Effect of dilutive securities:	'		'		'
Net income per Share, basic	'		'		$0.12
Participating Unvested Shares [Member]	'		'		'
Schedule of Computation of basic and diluted net income per share [Line Items]	'		'		'
Net income attributable to Qihoo 360 Technology Co. Ltd	3,175	[2]	2,049	[2]	1,124	[2]
Undistributed earnings allocated to participating securities	$3,175	[2]	$2,049	[2]	$1,124	[2]
Weighted average shares outstanding used in computing basic net income per share	5,749,393		7,733,645		11,292,535
Effect of dilutive securities:	'		'		'
Net income per Share, basic	$0.55		$0.26		$0.10
[1]	The calculation of the weighted average number of Class A and Class B ordinary shares for the purpose of diluted net income per share has considered the effect of certain potentially dilutive securities. For the year ended December 31, 2011, the incremental weighted average number of 19,578,504 and 4,345,724 ordinary shares from the assumed conversion of Series A, B and C preferred shares, and the exercise of share options and nonvested shares using the treasure stock method, respectively, has been included in the dilutive securities. For the years ended December 31, 2012 and 2013, the incremental weighted average number of 7,180,369 and 12,560,169 ordinary shares from the assumed exercise of share options and nonvested shares using the treasury stock method, respectively, has been included in the dilutive securities.
[2]	The net income attributable to Qihoo 360 Technology Co. Ltd. was allocated among Class A and Class B ordinary shares (see Note 19), preferred shares (See Note 20) and certain nonvested shares (see Note 22) pro rata on the basis of their right to participate in dividends.

Net_Income_Per_Share_Antidilut

Net Income Per Share (Antidilutive Securities Excluded)(Details)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'		'		'
Plus incremental weighted average ordinary shares from assumed exercise of stock options and nonvested shares using the treasury stock method	12,560,169	[1]	7,180,369	[1]	4,345,724	[1]
Plus incremental weighted average ordinary shares from assumed conversion of preferred share using treasury stock method	0		0		19,578,504
Share Option [Member]	'		'		'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'		'		'
Shares were excluded as their effect was anti-dilutive	533,054		4,990,513		2,552,844
Ordinary shares [Member]	'		'		'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'		'		'
Shares were excluded as their effect was anti-dilutive	2,578,779		'		'
[1]	The calculation of the weighted average number of Class A and Class B ordinary shares for the purpose of diluted net income per share has considered the effect of certain potentially dilutive securities. For the year ended December 31, 2011, the incremental weighted average number of 19,578,504 and 4,345,724 ordinary shares from the assumed conversion of Series A, B and C preferred shares, and the exercise of share options and nonvested shares using the treasure stock method, respectively, has been included in the dilutive securities. For the years ended December 31, 2012 and 2013, the incremental weighted average number of 7,180,369 and 12,560,169 ordinary shares from the assumed exercise of share options and nonvested shares using the treasury stock method, respectively, has been included in the dilutive securities.

Sharebased_Compensation_Narrat

Share-based Compensation (Narrative of Share Options) (Details) (USD $)

12 Months Ended

0 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

In Thousands, except Share data, unless otherwise specified

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Jan. 02, 2011

Feb. 14, 2011

Mar. 03, 2011

Jul. 02, 2011

Oct. 02, 2011

Jan. 20, 2012

Feb. 10, 2012

Apr. 15, 2012

Jul. 15, 2012

Oct. 15, 2012

Jan. 15, 2013

Apr. 15, 2013

Jul. 15, 2013

Oct. 15, 2013

Jul. 02, 2011

Jan. 02, 2011

Jan. 02, 2011

Jan. 02, 2011

Mar. 03, 2011

Mar. 03, 2011

Mar. 03, 2011

Jul. 15, 2012

Oct. 15, 2012

Jan. 15, 2013

Mar. 02, 2012

Jul. 15, 2012

Jan. 16, 2013

Jan. 25, 2006

Dec. 31, 2013

Dec. 31, 2011

Apr. 02, 2011

Dec. 31, 2013

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

2006 Employee Share Option Plan [Member]

2006 Employee Share Option Plan [Member]

2006 Employee Share Option Plan [Member]

2011 Employee Share Incentive Plan [Member]

2011 Employee Share Incentive Plan [Member]

January 1, 2011 [Member]

February 14, 2011 [Member]

March 3, 2011 [Member]

July 1, 2011 [Member]

October 1, 2011 [Member]

July 1, 2011 [Member]

January 20, 2012 [Member]

February 10, 2012 [Member]

April 15, 2012 [Member]

July 15, 2012 [Member]

October 15, 2012 [Member]

January 15, 2013 [Member]

April 15, 2013 [Member]

July 15, 2013 [Member]

October 15, 2013 [Member]

March 1, 2012 [Member]

July 15, 2012 [Member]

January 16, 2013 [Member]

Employees [Member]

Employees [Member]

Employees [Member]

Employees [Member]

Employees [Member]

Employees [Member]

Employees [Member]

Employees [Member]

Employees [Member]

Employees [Member]

Employees [Member]

Employees [Member]

Employees [Member]

Employees [Member]

Directors [Member]

Nonemployees [Member]

Nonemployees [Member]

Nonemployees [Member]

Nonemployees [Member]

Nonemployees [Member]

Nonemployees [Member]

Nonemployees [Member]

Nonemployees [Member]

Nonemployees [Member]

Nonemployees [Member]

Nonemployees [Member]

Nonemployees [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

Share options [Member]

January 1, 2011 [Member]

February 14, 2011 [Member]

March 3, 2011 [Member]

July 1, 2011 [Member]

October 1, 2011 [Member]

January 20, 2012 [Member]

February 10, 2012 [Member]

April 15, 2012 [Member]

July 15, 2012 [Member]

October 15, 2012 [Member]

January 15, 2013 [Member]

April 15, 2013 [Member]

July 15, 2013 [Member]

October 15, 2013 [Member]

July 1, 2011 [Member]

January 1, 2011 [Member]

January 1, 2011 [Member]

January 1, 2011 [Member]

March 3, 2011 [Member]

March 3, 2011 [Member]

March 3, 2011 [Member]

July 15, 2012 [Member]

October 15, 2012 [Member]

January 15, 2013 [Member]

March 1, 2012 [Member]

July 15, 2012 [Member]

January 16, 2013 [Member]

Maximum [Member]

Minimum [Member]

Maximum [Member]

Minimum [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

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'

'

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'

'

'

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'

'

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'

'

'

'

'

'

'

Share Options, Validity Period (in years)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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'

'

'

'

'

'

'

'

'

'

'

'

'

'

'10 years

'

'

'10 years

'

Options granted

1,521,000

19,177,900

'

'

3,786,200

700,000

704,500

2,689,200

375,000

40,000

1,834,500

935,000

171,500

427,500

771,500

701,500

406,000

188,000

145,500

33,000

40,000

80,000

3,726,200

700,000

684,500

2,689,200

375,000

1,834,500

935,000

171,500

417,500

761,500

681,500

406,000

188,000

145,500

40,000

60,000

'

'

20,000

'

'

10,000

10,000

20,000

33,000

40,000

80,000

'

'

'

'

'

Exercise price per option

'

'

'

'

$5.20

$5.20

$6

$12.94

$10.89

$9.67

$10.67

$11.35

$14.52

$10.95

$14.67

$21.09

$20.11

$35.27

$55.38

$14.09

$10.67

$12.94

$5.20

$5.20

$6

$12.94

$10.89

$10.67

$11.35

$14.52

$10.95

$14.67

$21.09

$20.11

$35.27

$55.38

$9.67

$5.20

'

'

$6

'

'

$10.95

$14.67

$21.09

$14.09

$10.67

$12.94

'

'

'

'

'

Period of advisory services related to share options granted to nonemployees

'

'

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'

'

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'

'

'

'

'

'

'

'

'

'

'4 years

'3 years

'

'4 years

'3 years

'4 years

'4 years

'4 years

'4 years

'4 years

'4 years

'

'

'

'

'

Percentage of options granted will be vested on each anniversary from grant date

'

'

'

'

'

'

'

'

'

'

'

'

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'

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'

'

'

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'

'

'

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'

'

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'

'

'

'

'

'

'

'

'

'

25.00%

'

'

'

Percentage of aggregate options will be vested from 12 months after start of vesting period

'

'

'

'

'

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'

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'

'

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'

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'

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'

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'

'

20.00%

Percentage of aggregate options will be vested from 24 months after start of vesting period

'

'

'

'

'

'

'

'

'

'

'

'

'

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'

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'

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'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

20.00%

Percentage of aggregate options will be vested from 36 months after start of vesting period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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'

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'

'

30.00%

Percentage of aggregate options will be vested from 48 months after start of vesting period

'

'

'

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'

'

'

'

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'

'

'

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'

'

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'

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'

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'

'

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'

'

'

'

'

'

'

'

'

'

30.00%

The weighted-average grant-date fair value per option granted during period

'

$13.19

$6.77

$4.36

'

'

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'

'

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'

'

'

'

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'

'

'

'

'

'

'

'

Total intrinsic value of options exercised during period

'

$138,364

$19,486

$311

'

'

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'

'

'

'

'

'

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'

'

'

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'

'

Share options, vested in period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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'

'

'

'

'

'

'

229,988

'

'

Allocated share-based compensation expense

'

21,921

26,997

34,504

'

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'

'

'

'

'

'

21,229

'

'

Unrecognized share-based compensation expense relating to share options

'

$33,509

'

'

'

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'

'

Period for recognition of unrecognized share-based compensation expense (in years)

'

'1 year 6 months 9 days

'

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'

'

'

'

Sharebased_Compensation_Fair_V

Share-based Compensation (Fair Value of Share Options, Valuation Assumptions) (Details)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions [Abstract]	'	'
Risk-free interest rate, minimum	3.40%	2.83%
Risk-free interest rate, maximum	4.02%	3.35%
Expected life (years)	'6 years 4 months 6 days	'6 years 4 months 6 days
Volatility, minimum	46.04%	46.98%
Volatility, maximum	46.68%	74.00%
Dividend yield	0.00%	0.00%

Sharebased_Compensation_Summar

Share-based Compensation (Summary of Information Regarding Share Options at Grant Date) (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Options granted	1,521,000
Share options [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Options granted	19,177,900
Share options [Member] | January 1, 2010 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	1-Jan-10
Options granted	110,000
Fair value per ordinary share at the grant date	1.8
Exercise price per option	2.2
Intrinsic value per option at the grant date	0
Share options [Member] | July 1, 2010 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	1-Jul-10
Options granted	5,039,000
Fair value per ordinary share at the grant date	2.58
Exercise price per option	2.8
Intrinsic value per option at the grant date	0
Share options [Member] | January 1, 2011 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	1-Jan-11
Options granted	3,786,200
Fair value per ordinary share at the grant date	5.01
Exercise price per option	5.2
Intrinsic value per option at the grant date	0
Share options [Member] | February 14, 2011 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	14-Feb-11
Options granted	700,000
Fair value per ordinary share at the grant date	6.6
Exercise price per option	5.2
Intrinsic value per option at the grant date	981
Share options [Member] | March 3, 2011 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	3-Mar-11
Options granted	704,500
Fair value per ordinary share at the grant date	7.21
Exercise price per option	6
Intrinsic value per option at the grant date	849
Share options [Member] | July 1, 2011 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	1-Jul-11
Options granted	2,689,200
Fair value per ordinary share at the grant date	14.09
Exercise price per option	12.94
Intrinsic value per option at the grant date	3,102
Share options [Member] | July 1, 2011 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	1-Jul-11
Options granted	40,000
Fair value per ordinary share at the grant date	14.09
Exercise price per option	9.67
Intrinsic value per option at the grant date	177
Share options [Member] | October 1, 2011 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	1-Oct-11
Options granted	375,000
Fair value per ordinary share at the grant date	10.89
Exercise price per option	10.89
Intrinsic value per option at the grant date	0
Share options [Member] | January 20, 2012 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	20-Jan-12
Options granted	1,834,500
Fair value per ordinary share at the grant date	11.67
Exercise price per option	10.67
Intrinsic value per option at the grant date	1,835
Share options [Member] | February 10, 2012 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	10-Feb-12
Options granted	935,000
Fair value per ordinary share at the grant date	11.17
Exercise price per option	11.35
Intrinsic value per option at the grant date	0
Share options [Member] | March 1, 2012 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	1-Mar-12
Options granted	33,000
Fair value per ordinary share at the grant date	14
Exercise price per option	14.09
Intrinsic value per option at the grant date	0
Share options [Member] | April 15, 2012 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	15-Apr-12
Options granted	171,500
Fair value per ordinary share at the grant date	14.52
Exercise price per option	14.52
Intrinsic value per option at the grant date	0
Share options [Member] | July 15, 2012 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	15-Jul-12
Options granted	427,500
Fair value per ordinary share at the grant date	10.95
Exercise price per option	10.95
Intrinsic value per option at the grant date	0
Share options [Member] | July 15, 2012 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	15-Jul-12
Options granted	40,000
Fair value per ordinary share at the grant date	10.95
Exercise price per option	10.67
Intrinsic value per option at the grant date	11
Share options [Member] | October 15, 2012 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	15-Oct-12
Options granted	771,500
Fair value per ordinary share at the grant date	14.73
Exercise price per option	14.67
Intrinsic value per option at the grant date	51
Share options [Member] | January 15, 2013 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	15-Jan-13
Options granted	701,500
Fair value per ordinary share at the grant date	20.55
Exercise price per option	21.09
Intrinsic value per option at the grant date	0
Share options [Member] | January 16, 2013 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	16-Jan-13
Options granted	80,000
Fair value per ordinary share at the grant date	20.33
Exercise price per option	12.94
Intrinsic value per option at the grant date	591
Share options [Member] | April 15, 2013 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	15-Apr-13
Options granted	406,000
Fair value per ordinary share at the grant date	19.92
Exercise price per option	20.11
Intrinsic value per option at the grant date	0
Share options [Member] | July 15, 2013 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	15-Jul-13
Options granted	188,000
Fair value per ordinary share at the grant date	36.85
Exercise price per option	35.27
Intrinsic value per option at the grant date	298
Share options [Member] | October 15, 2013 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Grant date	15-Oct-13
Options granted	145,500
Fair value per ordinary share at the grant date	57.03
Exercise price per option	55.38
Intrinsic value per option at the grant date	240

Sharebased_Compensation_Schedu

Share-based Compensation (Schedule of Share Options Roll Forward) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013
Number of options	'
Outstanding at beginning of period	15,148,014
Granted	1,521,000
Exercised	-3,982,385
Expired	-37,076
Forfeited	-1,167,040
Outstanding at end of period	11,482,513
Vested and exercisable	3,840,705
Vested and expect to vest	17,152,097
Weighted average exercise price per option	'
Outstanding at beginning of period	$7.20
Granted	$25.40
Exercised	$4.80
Expired	$11.60
Forfeited	$11.30
Outstanding at end of period	$10
Vested and exercisable	$5.50
Vested and expect to vest	$8.30

Sharebased_Compensation_Summar1

Share-based Compensation (Summary of Share Options Activities) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified			Share options [Member]	Share options [Member]	Share options [Member]	Share options [Member]	Share options [Member]	Share options [Member]	Share options [Member]	Share options [Member]	Share options [Member]	Share options [Member]	Share options [Member]	Share options [Member]	Share options [Member]	Share options [Member]	Share options [Member]	Share options [Member]	Share options [Member]	Share options [Member]	Share options [Member]	Share options [Member]	Share options [Member]
			June 30, 2009 [Member]	January 1, 2010 [Member]	July 1, 2010 [Member]	January 1, 2011 [Member]	February 14, 2011 [Member]	March 3, 2011 [Member]	July 1, 2011 [Member]	July 1, 2011 [Member]	October 1, 2011 [Member]	January 20, 2012 [Member]	February 10, 2012 [Member]	March 1, 2012 [Member]	April 15, 2012 [Member]	July 15, 2012 [Member]	July 15, 2012 [Member]	October 15, 2012 [Member]	January 15, 2013 [Member]	January 16, 2013 [Member]	April 15, 2013 [Member]	July 15, 2013 [Member]	October 15, 2013 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'	'	'	'	'	'	'	'	'	'	'	'	'	'	'	'	'	'
Grant date	'	'	30-Jun-09	1-Jan-10	1-Jul-10	1-Jan-11	14-Feb-11	3-Mar-11	1-Jul-11	1-Jul-11	1-Oct-11	20-Jan-12	10-Feb-12	1-Mar-12	15-Apr-12	15-Jul-12	15-Jul-12	15-Oct-12	15-Jan-13	16-Jan-13	15-Apr-13	15-Jul-13	15-Oct-13
Number outstanding	11,482,513	15,148,014	367,337	50,854	1,974,966	2,422,833	421,000	277,659	1,434,439	40,000	160,440	1,007,053	698,002	26,400	110,057	315,219	40,000	665,754	693,500	80,000	366,000	186,000	145,000
Weighted average remaining contractual term, options outstanding (in years)	'	'	'5 years 6 months	'6 years	'6 years 6 months	'7 years	'7 years 1 month 6 days	'7 years 2 months 12 days	'7 years 6 months	'7 years 6 months	'7 years 8 months 12 days	'8 years	'8 years 1 month 6 days	'8 years 2 months 12 days	'8 years 3 months 18 days	'8 years 6 months	'8 years 6 months	'8 years 9 months 18 days	'9 years	'9 years	'9 years 3 months 18 days	'9 years 6 months	'9 years 9 months 18 days
Exercise price per option, options outstanding	$10	$7.20	$1.50	$2.20	$2.80	$5.20	$5.20	$6	$12.94	$9.67	$10.89	$10.67	$11.35	$14.09	$14.52	$10.95	$10.67	$14.67	$21.09	$12.94	$20.11	$35.27	$55.38
Aggregate intrinsic value, options outstanding	'	'	$19,542	$2,670	$102,501	$119,930	$20,840	$13,522	$59,902	$1,801	$7,028	$44,344	$30,261	$1,072	$4,422	$13,790	$1,761	$26,652	$23,311	$3,341	$12,659	$3,615	$0
Number exercisable	3,840,705	'	371,710	33,354	1,596,466	795,683	71,000	80,409	408,556	16,000	50,440	98,653	122,003	0	14,057	49,220	8,000	125,154	0	0	0	0	0
Exercise price per option, options exercisable	$5.50	'	$1.50	$2.20	$2.80	$5.20	$5.20	$6	$12.94	$9.67	$10.89	$10.67	$11.35	$14.09	$14.52	$10.95	$10.67	$14.67	$21.09	$12.94	$20.11	$35.27	$55.38
Aggregate intrinsic value, options exercisable	'	'	$19,775	$1,751	$82,857	$39,386	$3,515	$3,916	$17,061	$721	$2,210	$4,344	$5,289	$0	$565	$2,153	$352	$5,010	$0	$0	$0	$0	$0

Sharebased_Compensation_Narrat1

Share-based Compensation (Narrative of Nonvested Shares) (Details)	1 Months Ended			12 Months Ended					23 Months Ended
In Thousands, except Share data, unless otherwise specified	Feb. 28, 2011	Feb. 28, 2011	Jan. 31, 2010	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2007	Jan. 19, 2006
	2006 Share Plan [Member]	2006 Share Plan [Member]	Nonvested shares [Member]	Nonvested shares [Member]	Nonvested shares [Member]	Nonvested shares [Member]	Nonvested shares [Member]	Nonvested shares [Member]	Nonvested shares [Member]	Nonvested shares [Member]
	Sino Honor Limited [Member]	Strengthen Goal Limited [Member]		USD ($)	USD ($)	USD ($)	Co-founders [Member]	2006 Share Plan [Member]	2006 Share Plan [Member]	2006 Share Plan [Member]
							USD ($)	CNY		Young Vision [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'	'	'	'	'
Ordinary shares allocated as equity incentive pool	'	'	'	'	'	'	'	'	'	18,086,101
Nonvested shares granted	'	'	'	5,148,971	4,845,877	3,255,976	1,000,000	'	9,951,000	'
Nonvested shares, shares, issued during period	'	'	3,517,544	'	'	'	'	'	'	'
Ordinary shares in equity pool, transferred between shareholders	11,826,000	5,550,654	'	'	'	'	'	'	'	'
Nonvested shares granted, vesting rights	'	'	'	'	'	'	'	'The nonvested shares granted under the 2006 Share Plan shall vest (i) 15 per cent of the aggregate number of shares 12 months after the start of vesting period; (ii) 20 per cent of the aggregate number of shares 24 months after the start of vesting period; (iii) 30 per cent of the aggregate number of shares so granted 36 months after the start of vesting period; and (iv) 35 per cent of the aggregate number of Shares 48 months after the start of vesting period	'	'
Aggregate repurchase price of nonvested shares under repurchase arrangement	'	'	'	'	'	'	'	1	'	'
Nonvested shares granted, repurchase arrangement	'	'	'	'	'	'	'	'(a) in all, on or before the second anniversary of the start of vesting period; (b) 50% of otherwise vested nonvested shares, after the second anniversary but before the fourth anniversary of the start of vesting period; or (c) no shares, after the fourth anniversary of the start of vesting period.	'	'
The total fair value of the nonvested shares vested during period	'	'	'	$70,980	$8,361	$7,671	'	'	'	'
Allocated share-based compensation expense	'	'	'	99,166	23,608	13,485	57,027	'	'	'
Unrecognized share-based compensation expense relating to nonvested share	'	'	'	$73,325	'	'	'	'	'	'
Period for recognition of unrecognized share-based compensation expense (in years)	'	'	'	'2 years 7 months 27 days	'	'	'	'	'	'

Sharebased_Compensation_Schedu1

Share-based Compensation (Schedule of Nonvested Shares Granted) (Details) (Nonvested shares [Member], USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Nonvested shares [Member]	'		'		'
Number of nonvested shares	'		'		'
Outstanding at beginning of period	8,772,238		8,184,251		11,133,594
Granted	5,148,971		4,845,877		3,255,976
Vested	-3,038,327		-3,136,471		-5,824,709
Forfeited	-812,088		-1,121,419		-380,610
Outstanding at end of period	10,070,794		8,772,238		8,184,251
Vested and to be transferred to grantees	18,416,568		'		'
Vested and expect to vest	27,188,805		'		'
Weighted average fair value per nonvested share at the grant date	'		'		'
Outstanding at beginning of period	$8.38	[1]	'		'
Granted	$32.02	[1]	$12.03	[1]	$7.76	[1]
Vested	$23.55	[1]	$2.32	[1]	$1.28	[1]
Forfeited	$13.92	[1]	$7.34	[1]	$1.58	[1]
Outstanding at end of period	$15.44	[1]	$8.38	[1]	'
[1]	The fair value of the underlying ordinary shares is the same as the fair value of the nonvested shares when calculating the weighted average fair value per nonvested share at the grant date.

Related_party_balances_and_tra2

Related party balances and transactions (Related parties and relationship with Group) (Details)	12 Months Ended
	Dec. 31, 2013
Related party F [Member]	'
Related Party Transaction [Line Items]	'
Relationship with the Group	'The Groups cost method investee
Related party G [Member]	'
Related Party Transaction [Line Items]	'
Relationship with the Group	'Noncontrolling interest shareholder of one of the Groups subsidiaries
Related party H [Member]	'
Related Party Transaction [Line Items]	'
Relationship with the Group	'The Groups equity method investee
Related party I [Member]	'
Related Party Transaction [Line Items]	'
Relationship with the Group	'The Groups equity method investee
Related party J [Member]	'
Related Party Transaction [Line Items]	'
Relationship with the Group	'The Groups equity method investee
Related party K [Member]	'
Related Party Transaction [Line Items]	'
Relationship with the Group	'The Groups equity method investee
Related party L [Member]	'
Related Party Transaction [Line Items]	'
Relationship with the Group	'The Groups equity method investee
Related party M [Member]	'
Related Party Transaction [Line Items]	'
Relationship with the Group	'The Groups equity method investee
Related party N [Member]	'
Related Party Transaction [Line Items]	'
Relationship with the Group	'Chairman and Chief Executive Officer of the Company
Related party O [Member]	'
Related Party Transaction [Line Items]	'
Relationship with the Group	'Noncontrolling interest shareholder of one of the Groups subsidiaries

Related_party_balances_and_tra3

Related party balances and transactions (Amount due from related parties) (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Related Party Transaction [Line Items]	'		'
Amounts due from related parties	$2,871		$0
Related party H [Member]	'		'
Related Party Transaction [Line Items]	'		'
Amounts due from related parties	1,542	[1]	0	[1]
Related party I [Member]	'		'
Related Party Transaction [Line Items]	'		'
Amounts due from related parties	496	[1]	0	[1]
Related party J [Member]	'		'
Related Party Transaction [Line Items]	'		'
Amounts due from related parties	627	[2]	0	[2]
Related party L [Member]	'		'
Related Party Transaction [Line Items]	'		'
Amounts due from related parties	$206	[3]	$0	[3]
[1]	The balances represent additional capital injection to equity method investees. As of December 31, 2013, the payments were made but the legal process has not been completed.
[2]	The balance mainly represents the receivable for the online marketing service provided to related party J.
[3]	It represents the unsecured interest-free bridge loans provided to related party L.

Related_party_balances_and_tra4

Related party balances and transactions (Amount due to related parties) (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Related Party Transaction [Line Items]	'		'
Amounts due to related parties	$517		$148
Related party G [Member]	'		'
Related Party Transaction [Line Items]	'		'
Amounts due to related parties	0	[1]	148	[1]
Related party K [Member]	'		'
Related Party Transaction [Line Items]	'		'
Amounts due to related parties	83	[2]	0	[2]
Related party J [Member]	'		'
Related Party Transaction [Line Items]	'		'
Amounts due to related parties	431	[3]	0	[3]
Related party M [Member]	'		'
Related Party Transaction [Line Items]	'		'
Amounts due to related parties	$3	[3]	$0	[3]
[1]	It represents the pre-operating expenses paid by related party G on behalf of one of the Group's subsidiary, which has been settled in February 2013. The Group deconsolidated this subsidiary in September 2013.
[2]	It represents the additional capital injection to be paid to related party K.
[3]	The balances represent the unpaid revenue sharing related to game operation.

Related_party_balances_and_tra5

Related party balances and transactions (Main transaction with related parties) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Marketing promotion received from [Member] | Related party F [Member]	'		'		'
Related Party Transaction [Line Items]	'		'		'
Amounts of transaction	$0		$0		$56
Online marketing promotion service fees received from [Member] | Related party J [Member]	'		'		'
Related Party Transaction [Line Items]	'		'		'
Amounts of transaction	387		0		0
Revenue sharing related to game operation paid to [Member] | Related party J [Member]	'		'		'
Related Party Transaction [Line Items]	'		'		'
Amounts of transaction	199		0		0
Revenue sharing related to game operation paid to [Member] | Related party M [Member]	'		'		'
Related Party Transaction [Line Items]	'		'		'
Amounts of transaction	266		0		0
Purchase of shares from [Member] | Related party N [Member]	'		'		'
Related Party Transaction [Line Items]	'		'		'
Amounts of transaction	1,989	[1]	0	[1]	0	[1]
Disposal equity interest of a subsidiary [Member] | Related party O [Member]	'		'		'
Related Party Transaction [Line Items]	'		'		'
Amounts of transaction	$0	[2]	$4,207	[2]	$0	[2]
[1]	In July 2013, the Group acquired 51% equity interest of an overseas internet service company from three selling shareholders, one of which is related party N. The Company settled the consideration of $1,989 for 28.53% equity interest from related party N by issuance of 51,722 ordinary shares, equivalent to 34,481 ADSs, based upon the closing price of the Company's ADSs at the acquisition date. Please refer to note 3 (2) for detail of the transaction.
[2]	On January 10, 2012, the Group entered into a termination agreement with related party U. Pursuant to the termination agreement, the Group agreed to dispose its 53.5% equity interest in one of its former subsidiaries to related party O.

Related_party_balances_and_tra6

Related party balances and transactions (Narrative) (Details) (USD $)	1 Months Ended					0 Months Ended
In Thousands, except Share data, unless otherwise specified	Jul. 31, 2013	Jul. 31, 2013	Jul. 31, 2013	Jul. 31, 2013	Jul. 31, 2013	Jan. 10, 2012
	Overseas internet service company [Member]	Overseas internet service company [Member]	Overseas internet service company [Member]	Overseas internet service company [Member]	Overseas internet service company [Member]	Former Subsidiary [Member]
		Ordinary shares [Member]	Related party N [Member]	Related party N [Member]	Related party N [Member]	Related party O [Member]
				Ordinary shares [Member]	ADS [Member]
Business Acquisition [Line Items]	'	'	'	'	'	'
Percentage of economic ownership	51.00%	'	'	'	'	'
Equity shares sold by a shareholder to the Group, percentage	'	'	28.53%	'	'	'
Business acquisition, number of shares issued	'	204,466	'	51,722	34,481	'
Business acquisition, value of shares issued	'	$7,864	$1,989	'	'	'
Percentage of disposed equity interest	'	'	'	'	'	53.50%

Commitments_and_Contingencies_1

Commitments and Contingencies (Capital Commitments) (Details) (Capital commitments [Member], USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013
Capital commitments [Member]	'
Long-term Purchase Commitment [Line Items]	'
Commitments contracted but not yet reflected in consolidated financial statements	$84

Commitments_and_Contingencies_2

Commitments and Contingencies (Operating Commitments) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating commitments, future minimum payments under commitments	'	'	'
2014	$8,712	'	'
2015	3,218	'	'
2016	1,591	'	'
2017	743	'	'
2018	702	'	'
Total	14,966	'	'
Rental expenses under operating leases	$5,057	$5,967	$4,261

Commitments_and_Contingencies_3

Commitments and Contingencies (Other Commitments) (Details) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Other commitments, future minimum payments under those commitments	'
2014	$15,000
2015	15,000
2016	15,000
2017	15,000
2018	10,583
Total	$70,583

Commitments_and_Contingencies_4

Commitments and Contingencies (Group as Defendant) (Details)

1 Months Ended

Sep. 30, 2011

Sep. 30, 2011

Oct. 31, 2010

Apr. 30, 2013

Apr. 30, 2013

Jun. 30, 2011

Jun. 30, 2011

Apr. 30, 2013

Oct. 31, 2012

Apr. 30, 2012

Oct. 31, 2013

Oct. 31, 2013

Unfair competitive practices claim, misled users [Member]

Unfair competitive practices claim, misled users [Member]

Unfair competitive practices claim, misled users [Member]

Unfair competitive practice claim, interferes with users' proper usage of other software [Member]

Unfair competitive practice claim, interferes with users' proper usage of other software [Member]

Unfair competitive practice claim, interferes with users' proper usage of other software [Member]

Unfair competitive practice claim, interferes with users' proper usage of other software [Member]

Unfair competitive practices and copyright infringement claim [Member]

Unfair competitive practices and copyright infringement claim [Member]

Unfair competitive practices and copyright infringement claim [Member]

Unfair competitive practices claim, change user default settings [Member]

Unfair competitive practices claim, blocking notifications of other type of software [Member]

Tencent [Member]

Tencent [Member]

Tencent [Member]

Tencent [Member]

Tencent [Member]

Tencent [Member]

Tencent [Member]

Two affiliates of Baidu [Member]

Two affiliates of Baidu [Member]

Two affiliates of Baidu [Member]

Sogou [Member]

Sogou [Member]

USD ($)

CNY

CNY

USD ($)

CNY

USD ($)

CNY

CNY

USD ($)

USD ($)

CNY

CNY

Loss Contingencies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Seeking value in damages

'

'

4,000,000

'

'

$19,800,000

125,000,000

'

$100,000,000

$10,000,000

45,500,000

50,000,000

Awarded value as damages

$63,553

400,000

'

$800,000

5,000,000

'

'

450,000

'

'

'

'

Commitments_and_Contingencies_5

Commitments and Contingencies (Group as Plaintiff) (Details)	1 Months Ended
	Mar. 31, 2012	Mar. 31, 2012	Nov. 30, 2010	Feb. 28, 2013	Nov. 30, 2013	Sep. 30, 2013	Nov. 30, 2011	Nov. 30, 2011
	Defamation claim [Member]	Defamation claim [Member]	Defamation claim [Member]	Defamation claim [Member]	Defamation claim [Member]	Defamation claim [Member]	Abuse of dominant market position claim [Member]	Abuse of dominant market position claim [Member]
	Tencent [Member]	Tencent [Member]	Tencent [Member]	Shanghai Jingwen [Member]	Sogou [Member]	Sogou [Member]	Tencent [Member]	Tencent [Member]
	USD ($)	CNY	CNY	CNY	CNY	CNY	USD ($)	CNY
Gain Contingencies [Line Items]	'	'	'	'	'	'	'	'
Seeking value in damages	$200,000	1,000,000	1	50,000,000	10,100,000	50,000,000	$23,800,000	150,000,000

Commitments_and_Contingencies_6

Commitments and Contingencies (Narrative of Loss Contingencies) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Commitments and Contingencies [Abstract]	'	'	'
Accrual for contingency loss	$900,000	$0	$0

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (Fair Value, Measurements, Recurring [Member], USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash equivalents-term deposits	$683,994	$153,805
Trading securities	253	179
Total	684,247	153,984
Quoted prices in active markets for identical instruments (level 1) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash equivalents-term deposits	683,994	153,805
Trading securities	253	179
Total	684,247	153,984
Significant other observable inputs (level 2) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash equivalents-term deposits	0	0
Trading securities	0	0
Total	0	0
Significant unobservable inputs (level 3) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Cash equivalents-term deposits	0	0
Trading securities	0	0
Total	$0	$0

Segments_and_geographic_inform2

Segments and geographic information (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]	'	'	'
Revenues	$671,088	$329,032	$167,851
Online advertising [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	417,133	221,488	123,048
Internet value-added services [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	252,684	103,316	43,567
Other services [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	1,271	4,078	346
Sales of third party anti-virus software [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	$0	$150	$890

Mainland_China_Contribution_Pl1

Mainland China Contribution Plan and Profit Appropriation (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Contribution Plan and Profit Appropriation [Abstract]	'	'	'
Provisions for full time employees benefits related to mandated contribution plan	$31,441	$18,125	$7,017
Minimum percentage of after-tax income to reserve fund before payment of dividends, required by local government	10.00%	'	'
Appropriation amount to statutory reserve funds	$12,074	$10,408	$5,503

Restricted_Net_Assets_Details

Restricted Net Assets (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Restricted Net Assets [Line Items]	'	'
Minimum percentage of after-tax income to reserve fund before payment of dividends, required by local government	10.00%	'
Restricted net assets	$261,895,000	$156,762,000
Paid in capital and statutory reserves [Member] | VIEs and VIEs' Subsidiaries [Member]	'	'
Restricted Net Assets [Line Items]	'	'
Restricted net assets	89,243,000	68,067,000
Paid in capital and statutory reserves [Member] | PRC subsidiaries [Member]	'	'
Restricted Net Assets [Line Items]	'	'
Restricted net assets	$172,652,000	$88,695,000

Subsequent_Events_Details

Subsequent Events (Details) (Subsequent Event [Member], Game platform operating company [Member], USD $)	1 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2014
Subsequent Event [Member] | Game platform operating company [Member]	'
Subsequent Event [Line Items]	'
Percentage of economic ownership	100.00%
Cash consideration	$67,400

Additional_Information_Financi2

Additional Information - Financial Statement Schedule I Condensed Financial Information of Parent Company (Condensed Balance Sheet) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
In Thousands, unless otherwise specified
ASSETS	'	'	'	'
Cash and cash equivalents	$1,013,465	$380,664	$343,731	$60,505
Restricted cash	2,368	1,905	'	'
Trading securities	253	179	'	'
Prepaid expenses and other current assets	80,538	26,802	'	'
Amounts due from subsidiaries and VIEs	2,871	0	'	'
Deferred tax assets - current	3,129	2,131	'	'
Total current assets	1,157,717	435,272	'	'
Acquired intangible assets, net	17,248	12,310	'	'
Cost method investment	46,012	12,562	'	'
Other non-current assets	39,621	9,335	'	'
Deferred tax assets - noncurrent	946	745	'	'
Total assets	1,568,896	689,529	'	'
LIABILITIES	'	'	'	'
Accrued expenses and other current liabilities	120,418	168,546	'	'
Deferred revenue-current	46,632	21,049	'	'
Amount due to subsidiaries and VIEs	517	148	'	'
Total current liabilities	208,598	203,714	'	'
Deferred revenue-noncurrent	3,544	6,762	'	'
Long-term debt	600,000	0	'	'
Total liabilities	814,818	211,266	'	'
EQUITY	'	'	'	'
Treasury stock	-139	0	'	'
Additional paid-in capital	568,675	420,662	'	'
Accumulated other comprehensive income	20,380	9,114	'	'
Retained earnings	119,639	32,061	'	'
Total Qihoo 360 Technology Co. Ltd. shareholders' equity	736,893	478,096	'	'
TOTAL EQUITY	754,078	478,263	371,492	2,722
TOTAL LIABILITIES AND EQUITY	1,568,896	689,529	'	'
Class A ordinary shares ($0.001 par value; 378,000,000 and 378,000,000 shares authorized as of December 31, 2012 and 2013, respectively; 123,472,524 and 134,123,218 shares issued and outstanding as of December 31, 2012 and 2013, respectively) [Member]	'	'	'	'
EQUITY	'	'	'	'
Ordinary shares	134	123	'	'
Class B ordinary shares ($0.001 par value; 122,000,000 and 122,000,000 shares authorized as of December 31, 2012 and 2013, respectively; 60,684,573 and 54,767,703 shares issued and outstanding as of December 31, 2012 and 2013, respectively) [Member]	'	'	'	'
EQUITY	'	'	'	'
Ordinary shares	55	61	'	'
Parent Company [Member]	'	'	'	'
ASSETS	'	'	'	'
Cash and cash equivalents	695,515	220,236	241,842	25,947
Restricted cash	300	300	'	'
Trading securities	253	179	'	'
Prepaid expenses and other current assets	3,206	8,416	'	'
Amounts due from subsidiaries and VIEs	167,395	29,805	'	'
Deferred tax assets - current	306	195	'	'
Total current assets	866,975	259,131	'	'
Acquired intangible assets, net	2,449	3,923	'	'
Investments in subsidiaries and VIEs	449,893	219,380	'	'
Cost method investment	17,139	1,379	'	'
Other non-current assets	11,707	0	'	'
Deferred tax assets - noncurrent	383	440	'	'
Total assets	1,348,546	484,253	'	'
LIABILITIES	'	'	'	'
Accrued expenses and other current liabilities	6,760	2,470	'	'
Deferred revenue-current	1,150	730	'	'
Amount due to subsidiaries and VIEs	2,306	1,316	'	'
Total current liabilities	10,216	4,516	'	'
Deferred revenue-noncurrent	1,437	1,641	'	'
Long-term debt	600,000	0	'	'
Total liabilities	611,653	6,157	'	'
EQUITY	'	'	'	'
Treasury stock	-139	0	'	'
Additional paid-in capital	568,675	420,662	'	'
Accumulated other comprehensive income	20,380	9,114	'	'
Retained earnings	147,788	48,136	'	'
Total Qihoo 360 Technology Co. Ltd. shareholders' equity	736,893	478,096	'	'
TOTAL EQUITY	736,893	478,096	'	'
TOTAL LIABILITIES AND EQUITY	1,348,546	484,253	'	'
Parent Company [Member] | Class A ordinary shares ($0.001 par value; 378,000,000 and 378,000,000 shares authorized as of December 31, 2012 and 2013, respectively; 123,472,524 and 134,123,218 shares issued and outstanding as of December 31, 2012 and 2013, respectively) [Member]	'	'	'	'
EQUITY	'	'	'	'
Ordinary shares	134	123	'	'
Parent Company [Member] | Class B ordinary shares ($0.001 par value; 122,000,000 and 122,000,000 shares authorized as of December 31, 2012 and 2013, respectively; 60,684,573 and 54,767,703 shares issued and outstanding as of December 31, 2012 and 2013, respectively) [Member]	'	'	'	'
EQUITY	'	'	'	'
Ordinary shares	$55	$61	'	'

Additional_Information_Financi3

Additional Information - Financial Statement Schedule I Condensed Financial Information of Parent Company (Condensed Balance Sheet Parenthetical) (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]	'	'	'
Ordinary shares, par value	$0.00	$0.00	$0.00
Ordinary shares, shares authorized	500,000,000	500,000,000	500,000,000
Common Class A [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Ordinary shares, par value	$0.00	$0.00	'
Ordinary shares, shares authorized	378,000,000	378,000,000	'
Ordinary shares, shares issued	123,472,524	123,472,524	'
Ordinary shares, shares outstanding	134,123,218	134,123,218	'
Common Class B [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Ordinary shares, par value	$0.00	$0.00	'
Ordinary shares, shares authorized	122,000,000	122,000,000	'
Ordinary shares, shares issued	60,684,573	60,684,573	'
Ordinary shares, shares outstanding	54,767,703	54,767,703	'
Parent Company [Member] | Common Class A [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Ordinary shares, par value	$0.00	$0.00	'
Ordinary shares, shares authorized	378,000,000	378,000,000	'
Ordinary shares, shares issued	123,472,524	123,472,524	'
Ordinary shares, shares outstanding	134,123,218	134,123,218	'
Parent Company [Member] | Common Class B [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Ordinary shares, par value	$0.00	$0.00	'
Ordinary shares, shares authorized	122,000,000	122,000,000	'
Ordinary shares, shares issued	60,684,573	60,684,573	'
Ordinary shares, shares outstanding	54,767,703	54,767,703	'

Additional_Information_Financi4

Additional Information - Financial Statement Schedule I Condensed Financial Information of Parent Company (Condensed Statements of Operations) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]	'	'	'
Cost of revenues	$87,838	$32,802	$18,918
Operating expenses:	'	'	'
Selling and marketing	110,104	58,178	46,836
General and administrative	116,200	34,295	19,054
Product development	255,248	156,269	64,962
Total operating expenses	482,500	250,090	130,939
Loss from operations	103,099	48,710	18,145
Interest income	10,398	6,715	2,594
Interest expense	-5,572	0	-53
Other income	590	1,243	-3
Exchange gain	5,105	49	6,294
Impairment loss on long-term investments	-5,004	-2,302	-902
Change in unrealized holding (loss) gain of trading securities	75	-52	-220
Realized gain from sales of trading securities	252	0	0
Dividend income from a cost method investee	413	0	0
Income tax expense	-23,423	-11,379	-10,874
Net income attributable to Qihoo 360 Technology Co. Ltd.	99,652	46,746	15,603
Net income attributable to ordinary shareholders of Qihoo 360 Technology Co. Ltd.	99,652	46,746	14,832
Series A Preferred Stock [Member]	'	'	'
Operating expenses:	'	'	'
Net income attributable to Qihoo 360 Technology Co. Ltd.	'	'	203
Accretion of convertible participating redeemable preferred shares	'	'	203
Series B Preferred Stock [Member]	'	'	'
Operating expenses:	'	'	'
Net income attributable to Qihoo 360 Technology Co. Ltd.	'	'	313
Accretion of convertible participating redeemable preferred shares	'	'	313
Series C Preferred Stock [Member]	'	'	'
Operating expenses:	'	'	'
Net income attributable to Qihoo 360 Technology Co. Ltd.	'	'	255
Accretion of convertible participating redeemable preferred shares	'	'	255
Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Cost of revenues	0	4	16
Operating expenses:	'	'	'
Selling and marketing	15,519	21,289	31,473
General and administrative	73,372	10,815	6,788
Product development	38,211	21,782	12,283
Total operating expenses	127,102	53,886	50,544
Loss from operations	-127,102	-53,890	-50,560
Interest income	6,341	4,702	1,662
Interest expense	-5,551	0	0
Other income	1,197	1,277	0
Exchange gain	5,100	412	6,514
Impairment loss on long-term investments	0	0	-666
Change in unrealized holding (loss) gain of trading securities	75	-52	-220
Realized gain from sales of trading securities	252	0	0
Dividend income from a cost method investee	413	0	0
Loss before income tax expense and earnings from subsidiary and VIEs	-119,275	-47,551	-43,270
Income in earnings of subsidiaries and VIEs	219,247	94,639	58,873
Income before income tax expense	99,972	47,088	15,603
Income tax expense	-320	-342	0
Net income attributable to Qihoo 360 Technology Co. Ltd.	99,652	46,746	15,603
Net income attributable to ordinary shareholders of Qihoo 360 Technology Co. Ltd.	99,652	46,746	14,832
Parent Company [Member] | Series A Preferred Stock [Member]	'	'	'
Operating expenses:	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	203
Parent Company [Member] | Series B Preferred Stock [Member]	'	'	'
Operating expenses:	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	313
Parent Company [Member] | Series C Preferred Stock [Member]	'	'	'
Operating expenses:	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	$255

Additional_Information_Financi5

Additional Information - Financial Statement Schedule I Condensed Financial Information of Parent Company (Condensed Statements of Comprehensive Income) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]	'	'	'
Net income	$97,849	$46,471	$14,544
Other comprehensive income, net of tax:	'	'	'
Foreign currency translation adjustments	11,104	2,849	3,278
Other comprehensive income	11,104	2,849	3,278
Comprehensive income	108,953	49,320	17,822
Add: Comprehensive loss attributable to noncontrolling interest	1,965	277	1,027
Comprehensive income attributable to Qihoo 360 Technology Co. Ltd.	110,918	49,597	18,849
Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Net income	99,652	46,746	15,603
Other comprehensive income, net of tax:	'	'	'
Foreign currency translation adjustments	11,266	2,851	3,246
Other comprehensive income	11,266	2,851	3,246
Comprehensive income	110,918	49,597	18,849
Add: Comprehensive loss attributable to noncontrolling interest	0	0	0
Comprehensive income attributable to Qihoo 360 Technology Co. Ltd.	$110,918	$49,597	$18,849

Additional_Information_Financi6

Additional Information - Financial Statement Schedule I Condensed Financial Information of Parent Company (Condensed Statements of Changes in Equity) (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]	'	'	'
Beginning Balance, amount	$478,263	$371,492	$2,722
Issuance of ordinary shares in connection with share-based compensation arrangements, amount	1	3	3
Share repurchase, amount	-139	'	'
Share-based compensation	121,087	50,605	47,989
Issuance of ordinary shares in connection with business acquisitions, amount	7,864	'	'
Issuance of ordinary shares in connection with exercise of share options, shares (in shares)	3,982,385	'	'
Issuance of ordinary shares in connection with exercise of share options, amount	19,071	6,965	48
Issuance of ordinary shares upon initial public offering ("IPO"), net of offering costs of $2,342, amount	'	'	231,549
Conversion of participating redeemable preferred shares to ordinary shares, amount	'	'	70,971
Disposal of noncontrolling interest in subsidiaries	-544	-544	-389
Net income	97,849	46,471	14,544
Foreign currency translation adjustments	11,104	2,849	3,278
Ending Balance, amount	754,078	478,263	371,492
Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Beginning Balance, amount	478,096	'	'
Net income	99,652	46,746	15,603
Foreign currency translation adjustments	11,266	2,851	3,246
Ending Balance, amount	736,893	478,096	'
Series A Preferred Stock [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	-203
Series A Preferred Stock [Member] | Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	-203
Series B Preferred Stock [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	-313
Series B Preferred Stock [Member] | Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	-313
Series C Preferred Stock [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	-255
Series C Preferred Stock [Member] | Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	-255
Total Qihoo 360 Technology Co. Ltd. shareholders' equity [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Beginning Balance, amount	478,096	370,853	2,215
Issuance of ordinary shares in connection with share-based compensation arrangements, amount	1	3	3
Share repurchase, amount	-139	'	'
Share-based compensation	121,087	50,605	47,989
Issuance of ordinary shares in connection with business acquisitions, amount	7,864	'	'
Issuance of ordinary shares in connection with exercise of share options, amount	19,071	6,965	48
Issuance of ordinary shares upon initial public offering ("IPO"), net of offering costs of $2,342, amount	'	'	231,549
Conversion of participating redeemable preferred shares to ordinary shares, amount	'	'	70,971
Disposal of noncontrolling interest in subsidiaries	-5	73	'
Net income	99,652	46,746	15,603
Foreign currency translation adjustments	11,266	2,851	3,246
Ending Balance, amount	736,893	478,096	370,853
Total Qihoo 360 Technology Co. Ltd. shareholders' equity [Member] | Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Beginning Balance, amount	478,096	370,853	2,215
Issuance of ordinary shares in connection with share-based compensation arrangements, amount	1	3	3
Share repurchase, amount	-139	'	'
Share-based compensation	121,087	50,605	47,989
Issuance of ordinary shares in connection with business acquisitions, amount	7,864	'	'
Issuance of ordinary shares in connection with exercise of share options, amount	19,071	6,965	48
Issuance of ordinary shares upon initial public offering ("IPO"), net of offering costs of $2,342, amount	'	'	231,549
Conversion of participating redeemable preferred shares to ordinary shares, amount	'	'	70,971
Disposal of noncontrolling interest in subsidiaries	-5	73	'
Net income	99,652	46,746	15,603
Foreign currency translation adjustments	11,266	2,851	3,246
Ending Balance, amount	736,893	478,096	370,853
Total Qihoo 360 Technology Co. Ltd. shareholders' equity [Member] | Series A Preferred Stock [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	-203
Total Qihoo 360 Technology Co. Ltd. shareholders' equity [Member] | Series A Preferred Stock [Member] | Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	-203
Total Qihoo 360 Technology Co. Ltd. shareholders' equity [Member] | Series B Preferred Stock [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	-313
Total Qihoo 360 Technology Co. Ltd. shareholders' equity [Member] | Series B Preferred Stock [Member] | Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	-313
Total Qihoo 360 Technology Co. Ltd. shareholders' equity [Member] | Series C Preferred Stock [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	-255
Total Qihoo 360 Technology Co. Ltd. shareholders' equity [Member] | Series C Preferred Stock [Member] | Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	-255
Ordinary shares [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Beginning Balance, shares (in shares)	184,157,097	179,029,251	71,560,740
Beginning Balance, amount	184	179	72
Issuance of ordinary shares in connection with share-based compensation arrangements, shares (in shares)	561,517	3,512,394	3,059,779
Issuance of ordinary shares in connection with share-based compensation arrangements, amount	1	3	3
Share repurchase, shares (in shares)	-14,544	'	'
Issuance of ordinary shares in connection with business acquisitions, shares (in shares)	204,466	'	'
Issuance of ordinary shares in connection with exercise of share options, shares (in shares)	3,982,385	1,615,452	31,172
Issuance of ordinary shares in connection with exercise of share options, amount	4	2	'
Issuance of ordinary shares upon initial public offering ("IPO"), shares (in shares)	'	'	26,063,544
Issuance of ordinary shares upon initial public offering ("IPO"), net of offering costs of $2,342, amount	'	'	26
Conversion of participating redeemable preferred shares to ordinary shares, shares (in shares)	'	'	78,314,016
Conversion of participating redeemable preferred shares to ordinary shares, amount	'	'	78
Ending Balance, shares (in shares)	188,890,921	184,157,097	179,029,251
Ending Balance, amount	189	184	179
Ordinary shares [Member] | Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Beginning Balance, shares (in shares)	184,157,097	179,029,251	71,560,740
Beginning Balance, amount	184	179	72
Issuance of ordinary shares in connection with share-based compensation arrangements, shares (in shares)	561,517	3,512,394	3,059,779
Issuance of ordinary shares in connection with share-based compensation arrangements, amount	1	3	3
Share repurchase, shares (in shares)	-14,544	'	'
Issuance of ordinary shares in connection with business acquisitions, shares (in shares)	204,466	'	'
Issuance of ordinary shares in connection with exercise of share options, shares (in shares)	3,982,385	1,615,452	31,172
Issuance of ordinary shares in connection with exercise of share options, amount	4	2	'
Issuance of ordinary shares upon initial public offering ("IPO"), shares (in shares)	'	'	26,063,544
Issuance of ordinary shares upon initial public offering ("IPO"), net of offering costs of $2,342, amount	'	'	26
Conversion of participating redeemable preferred shares to ordinary shares, shares (in shares)	'	'	78,314,016
Conversion of participating redeemable preferred shares to ordinary shares, amount	'	'	78
Ending Balance, shares (in shares)	188,890,921	184,157,097	179,029,251
Ending Balance, amount	189	184	179
Treasury Stock [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Share repurchase, amount	-139	'	'
Ending Balance, amount	-139	'	'
Treasury Stock [Member] | Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Share repurchase, amount	-139	'	'
Ending Balance, amount	-139	'	'
Additional Paid-in Capital [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Beginning Balance, amount	420,662	363,021	12,568
Share-based compensation	121,087	50,605	47,989
Issuance of ordinary shares in connection with business acquisitions, amount	7,864	'	'
Issuance of ordinary shares in connection with exercise of share options, amount	19,067	6,963	48
Issuance of ordinary shares upon initial public offering ("IPO"), net of offering costs of $2,342, amount	'	'	231,523
Conversion of participating redeemable preferred shares to ordinary shares, amount	'	'	70,893
Disposal of noncontrolling interest in subsidiaries	-5	73	'
Ending Balance, amount	568,675	420,662	363,021
Additional Paid-in Capital [Member] | Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Beginning Balance, amount	420,662	363,021	12,568
Share-based compensation	121,087	50,605	47,989
Issuance of ordinary shares in connection with business acquisitions, amount	7,864	'	'
Issuance of ordinary shares in connection with exercise of share options, amount	19,067	6,963	48
Issuance of ordinary shares upon initial public offering ("IPO"), net of offering costs of $2,342, amount	'	'	231,523
Conversion of participating redeemable preferred shares to ordinary shares, amount	'	'	70,893
Disposal of noncontrolling interest in subsidiaries	-5	73	'
Ending Balance, amount	568,675	420,662	363,021
Accumulated other comprehensive income [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Beginning Balance, amount	9,114	6,263	3,017
Foreign currency translation adjustments	11,266	2,851	3,246
Ending Balance, amount	20,380	9,114	6,263
Accumulated other comprehensive income [Member] | Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Beginning Balance, amount	9,114	6,263	3,017
Foreign currency translation adjustments	11,266	2,851	3,246
Ending Balance, amount	20,380	9,114	6,263
(Accumulated deficit) retained earnings [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Beginning Balance, amount	32,061	-4,277	-13,606
Net income	99,652	46,746	15,603
Ending Balance, amount	119,639	32,061	-4,277
(Accumulated deficit) retained earnings [Member] | Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Beginning Balance, amount	48,136	1,390	-13,442
Net income	99,652	46,746	15,603
Ending Balance, amount	147,788	48,136	1,390
(Accumulated deficit) retained earnings [Member] | Series A Preferred Stock [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	-203
(Accumulated deficit) retained earnings [Member] | Series A Preferred Stock [Member] | Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	-203
(Accumulated deficit) retained earnings [Member] | Series B Preferred Stock [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	-313
(Accumulated deficit) retained earnings [Member] | Series B Preferred Stock [Member] | Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	-313
(Accumulated deficit) retained earnings [Member] | Series C Preferred Stock [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	-255
(Accumulated deficit) retained earnings [Member] | Series C Preferred Stock [Member] | Parent Company [Member]	'	'	'
Condensed Financial Statements, Captions [Line Items]	'	'	'
Accretion of convertible participating redeemable preferred shares	'	'	($255)

Additional_Information_Financi7

Additional Information - Financial Statement Schedule I Condensed Financial Information of Parent Company (Condensed Statements of Changes in Equity Parenthetical) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]	'
Offering Costs	$2,763
Parent Company [Member]	'
Condensed Financial Statements, Captions [Line Items]	'
Offering Costs	$2,342

Additional_Information_Financi8

Additional Information - Financial Statement Schedule I Condensed Financial Information of Parent Company (Condensed Statements of Cash Flow) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:	'	'	'
Net income	$97,849	$46,471	$14,544
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'
Share-based compensation	121,087	50,605	47,989
Depreciation and amortization	42,629	16,457	4,227
Unrealized holding loss (gain) on trading securities	-75	52	220
Realized gain from sales of trading securities	-252	0	0
Dividend income from a cost method investee	-413	0	0
Loss from impairment of long-term investments	5,004	2,302	902
Prepaid expenses and other current assets	-40,271	-8,404	-8,684
Deferred taxes	837	-1,204	-315
Other noncurrent assets	-3,010	392	-4,077
Accrued expenses and other current liabilities	53,605	23,274	11,554
Deferred revenue	20,466	10,354	10,744
Amount due from/to subsidiaries and VIEs	366	83	964
Net cash provided by (used in) operating activities	210,226	117,788	82,303
Cash flows from investing activities:	'	'	'
Restricted cash	-431	-1,902	0
Purchase of intangible assets	-3,068	-5,073	-1,457
Capital contribution for cost method investments	-35,617	-8,023	-7,599
Proceeds from sale of trading securities	762	0	0
Dividends received from a cost method investee	413	313	0
Net cash used in investing activities	-196,874	-83,927	-34,811
Cash flows from financing activities:	'	'	'
Proceeds from issuance of Convertible Senior Notes (net of issuance cost of $12,150)	587,850	0	0
Proceeds from exercise of share options	23,678	2,089	20
Proceeds from issuance of ordinary shares upon IPO	0	0	234,312
Payment of IPO costs	0	0	-2,611
Payment for share repurchase	0	-139	0
Net cash provided by financing activities	613,498	1,986	233,280
Net increase (decrease) in cash and cash equivalents	632,801	36,933	283,226
Cash and cash equivalents at beginning of year	380,664	343,731	60,505
Cash and cash equivalents at end of year	1,013,465	380,664	343,731
Parent Company [Member]	'	'	'
Cash flows from operating activities:	'	'	'
Net income	99,652	46,746	15,603
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'
Share-based compensation	121,087	50,605	47,989
Gain from investments in subsidiaries and VIEs	-219,247	-94,639	-58,873
Depreciation and amortization	1,476	582	243
Unrealized holding loss (gain) on trading securities	-75	52	220
Realized gain from sales of trading securities	-252	0	0
Dividend income from a cost method investee	-413	0	0
Loss from impairment of long-term investments	0	0	666
Prepaid expenses and other current assets	463	-2,307	-352
Deferred taxes	-53	-178	-457
Other noncurrent assets	743	0	0
Accrued expenses and other current liabilities	5,488	149	92
Deferred revenue	215	700	1,671
Amount due from/to subsidiaries and VIEs	-128,738	-21,816	-20
Net cash provided by (used in) operating activities	-119,654	-20,106	6,782
Cash flows from investing activities:	'	'	'
Restricted cash	0	-300	0
Purchase of intangible assets	-1,500	-1,500	0
Purchase of trading securities	-510	0	-451
Capital contribution for cost method investments	-15,760	-450	-929
Proceeds from sale of trading securities	762	0	0
Dividends received from a cost method investee	413	0	0
Investments in subsidiaries	0	-1,200	-21,500
Net cash used in investing activities	-16,595	-3,450	-22,880
Cash flows from financing activities:	'	'	'
Proceeds from issuance of Convertible Senior Notes (net of issuance cost of $12,150)	587,850	0	0
Proceeds from exercise of share options	23,678	2,089	20
Proceeds from issuance of ordinary shares upon IPO	0	0	234,312
Payment of IPO costs	0	0	-2,339
Payment for share repurchase	0	-139	0
Net cash provided by financing activities	611,528	1,950	231,993
Net increase (decrease) in cash and cash equivalents	475,279	-21,606	215,895
Cash and cash equivalents at beginning of year	220,236	241,842	25,947
Cash and cash equivalents at end of year	$695,515	$220,236	$241,842

Additional_Information_Financi9

Additional Information - Financial Statement Schedule I Condensed Financial Information of Parent Company (Condensed Statements of Cash Flow Parenthetical) (Details) (Convertible Senior Notes [Member], USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013
Convertible Senior Notes [Member]	'
Condensed Financial Statements, Captions [Line Items]	'
Debt Issuance Costs Excluding Auditing Fee	$12,150