Income Taxes - Schedule of Movement in Valuation Allowance (Detail) ¥ in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2014 USD ($)	Dec. 31, 2014 CNY (¥)	Dec. 31, 2013 CNY (¥)
Valuation Allowance [Abstract]
At the beginning of the year	$ 3,304	¥ 20,502	¥ 21,949
Current year movement	118	728	(1,447)
At the end of the year	$ 3,422	¥ 21,230	¥ 20,502

Amount of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards expected to be realized or consumed within one year or operating cycle, if longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=37586315&loc=d3e31917-109318

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=37586315&loc=d3e31928-109318

Name:	us-gaap_DeferredTaxAssetsValuationAllowanceCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant