Revenue from the sale of advertising time (such as television and radio) or space (newspaper or magazine pages). May also include advertising, marketing and promotional services rendered during the reporting period.

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Principal accounting policies (Convenience Translation - Narrative) (Details) ¥ in Thousands	12 Months Ended
	Dec. 31, 2017 CNY (¥)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 CNY (¥)	Dec. 31, 2015 CNY (¥)	Jan. 01, 2018 CNY (¥)	Dec. 29, 2017
Convenience translation
Rate of translations of amounts from RMB into US$						6.5063
Impairment of long-lived assets
Impairment charges of intangible assets			¥ 3,828	¥ 57,199
Advertising Revenue	¥ 112,778		41,685	¥ 62,740
Subsequent Event [Member]
New accounting pronouncements and changes in accounting principles
New Accounting Pronouncement or Change in Accounting Principle, Reclassification From AOCI To Retained Earnings					¥ 87,802
Accounting Standards Update 2015-17 [Member]
Deferred costs, noncurrent
Deferred Tax Assets, Net, Noncurrent			¥ 107,309
Use Rights [Member]
Finite-lived intangible assets, net
Useful life of intangible assets	40 years	40 years