Net income/(loss) per share (Details) ¥ / shares in Units, $ / shares in Units, ¥ in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2017 CNY (¥) ¥ / shares shares	Dec. 31, 2016 CNY (¥) ¥ / shares shares	Dec. 31, 2015 CNY (¥) ¥ / shares shares
Numerator:
Net income/(loss) from continuing operations attributable to ordinary shareholders	$ 17,957	¥ 116,819	¥ (2,000,444)	¥ (7,731,760)
Net loss from discontinued operations attributable to ordinary shareholders	(41,356)	(269,076)	(1,806,346)	(1,376,180)
Net loss attributable to ordinary shareholders	$ (23,399)	¥ (152,257)	¥ (3,806,790)	¥ (9,107,940)
Denominator:
Weighted average number of shares - basic	2,844,826,014	2,844,826,014	2,804,767,889	2,735,034,034
Adjustments for dilutive options and RSUs	66,635,803	66,635,803
Weighted average number of shares - diluted	2,911,461,817	2,911,461,817	2,804,767,889	2,735,034,034
Basic net income/(loss) per share from continuing operations attributable to ordinary shareholders \| (per share)	$ 0.01	¥ 0.04	¥ (0.71)	¥ (2.83)
Basic net loss per share from discontinued operations attributable to ordinary shareholders \| (per share)	(0.01)	(0.09)	(0.64)	(0.50)
Net loss per share - basic \| (per share)	(0.01)	(0.05)	(1.36)	(3.33)
Diluted net income/(loss) per share from continuing operations attributable to ordinary shareholders \| (per share)	0.01	0.04	(0.71)	(2.83)
Diluted net loss per share from discontinued operations attributable to ordinary shareholders \| (per share)	(0.01)	(0.09)	(0.64)	(0.50)
Net loss per share - diluted \| (per share)	$ (0.01)	¥ (0.05)	¥ (1.36)	¥ (3.33)

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) from continuing operations per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) derived from continuing operations during the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Per basic share amount, after tax, of income (loss) from the day-to-day business activities of the discontinued operation and gain (loss) from the disposal of the discontinued operation.

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Per diluted share amount, after tax, of income (loss) from the day-to-day business activities of the discontinued operation and gain (loss) from the disposal of the discontinued operation.

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Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

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Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) from continuing operations available to common shareholders.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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