Fair Value Measurement (Tables)

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Assets Measured at Fair Value on Recurring Basis

Assets measured at fair value on a recurring basis are summarized below:

	Fair Value Measurement at December 31, 2016 Using
	Quoted Prices in Active Market for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Unobservable inputs (Level 3)		Fair Value at December 31, 2016
	RMB		RMB		RMB		RMB		US$
Cash equivalents
Time deposits		—		2,099,200		—		2,099,200		302,348
Money market fund		225,848		—				225,848		32,529
Restricted cash		—		9,319		—		9,319		1,342
Short-term investments										—
Term deposits		—		1,804,208		—		1,804,208		259,860
Adjustable-rate financial products		—		625,883		—		625,883		90,146
		225,848		4,538,610		—		4,764,458		686,225

	Fair Value Measurement at December 31, 2015 Using
	Quoted Prices in Active Market for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Unobservable inputs (Level 3)		Fair Value at December 31, 2015
	RMB		RMB		RMB		RMB
Cash equivalents
Time deposits		—		97,404		—		97,404
Restricted cash		—		61,091		—		61,091
Short-term investments
Term deposits		—		1,955,315		—		1,955,315
		—		2,113,810		—		2,113,810