Income Taxes (Movement of valuation allowance of deferred tax assets) (Details) ¥ in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2016 CNY (¥)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 CNY (¥)	Dec. 31, 2014 CNY (¥)
Income Taxes [Abstract]
Balance as of January 1	¥ 4,676	$ 673	¥ 7,101	¥ 5,569
Additions	6,838	985	2,121	3,153
Reversals	(112)	(16)	(4,546)	(1,621)
Balance as of December 31	¥ 11,402	$ 1,642	¥ 4,676	¥ 7,101

Amount of valuation allowance of deferred tax asset attributable to deductible temporary differences and carryforwards, classified as noncurrent.

Reference 1: 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=65882285&loc=d3e32537-109319

Reference 2: 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=75116654&loc=d3e31917-109318

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=75116654&loc=d3e31928-109318

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