Condensed Financial Information of the Parent Company - Condensed Balance Sheets (Parenthetical) (Detail) - $ / shares	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2013
Class A Ordinary Shares [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Ordinary shares, par value	$ 0.01
Ordinary shares, shares authorized	99,931,211,060	99,931,211,060
Ordinary shares, shares issued	115,297,224	51,230,242
Ordinary shares, shares outstanding	115,297,224	51,230,242	36,347,496
Class B Ordinary Shares [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Ordinary shares, par value	$ 0.01
Ordinary shares, shares authorized	68,788,940	68,788,940
Ordinary shares, shares issued	0	61,824,328
Ordinary shares, shares outstanding	0	61,824,328	68,788,940
Parent Company [Member] \| Class A Ordinary Shares [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Ordinary shares, par value	$ 0.01
Ordinary shares, shares authorized	99,931,211,060	99,931,211,060
Ordinary shares, shares issued	115,297,224	51,230,242
Ordinary shares, shares outstanding	115,297,224	51,230,242
Parent Company [Member] \| Class B Ordinary Shares [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Ordinary shares, par value	$ 0.01
Ordinary shares, shares authorized	68,788,940	68,788,940
Ordinary shares, shares issued	0	61,824,328
Ordinary shares, shares outstanding	0	61,824,328

Face amount or stated value per share of common stock.

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- Definition

The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

+ References

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- Definition

Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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- Definition

Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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