The portion of the carrying value of long-term convertible debt as of the balance sheet date that is scheduled to be repaid within one year or in the normal operating cycle if longer. Convertible debt is a financial instrument which can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder.

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Carrying amount of long-term convertible debt as of the balance sheet date, net of the amount due in the next twelve months or greater than the normal operating cycle, if longer. The debt is convertible into another form of financial instrument, typically the entity's common stock.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Start date of debt instrument redemption period, in CCYY-MM-DD format.

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Face (par) amount of the original debt instrument that was repurchased.

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No definition available.

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Amount of the cost of borrowed funds accounted for as interest expense.

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Convertible bonds (Narrative) (Details) ¥ in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017 CNY (¥)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 CNY (¥)	Dec. 31, 2015 CNY (¥)	Dec. 31, 2017 USD ($)	Apr. 01, 2017 USD ($)	Dec. 31, 2016 USD ($)	Mar. 18, 2014 USD ($)
Convertible bonds [Line Items]
Interest expense	¥ 32,122	$ 4,937	¥ 81,085	¥ 97,125
Convertible bonds, current
Convertible bonds, current	0		2,768,469		$ 0	$ 1,000
Convertible bonds, non-current
Debt Instrument, Repurchased Face Amount						$ 399,000
Convertible bonds, non-current	6,536		0		$ 1,005
Convertible bonds [Member]
Convertible bonds [Line Items]
Interest expense \| ¥	¥ 20,820		81,085
2.25% Convertible Senior Notes due 2019 [Member]
Convertible bonds [Line Items]
Aggregate principle amount								$ 400,000
Interest rate (as a percent)	2.25%				2.25%
Convertible bonds, current
Convertible bonds, current			¥ 2,768,469				$ 399,000
2.25% Convertible Senior Notes due 2019 [Member] \| Contingent redemption option [Member]
Convertible bonds [Line Items]
Redemption period, start date	Apr. 01, 2019	Apr. 01, 2019