Distribution of Profit - Additional Information (Detail) - CNY (¥)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Equity [Abstract]
Dividends paid on outstanding common stock	¥ 0	¥ 0	¥ 0
Distributable reserves	¥ 0	¥ 0

Amount of paid and unpaid common stock dividends declared with the form of settlement in stock.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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