SHARE-BASED COMPENSATION (Narrative) (Details)
1 Months Ended 12 Months Ended 12 Months Ended 1 Months Ended 0 Months Ended 12 Months Ended 12 Months Ended 12 Months Ended 12 Months Ended
Dec. 31, 2012
CNY
Rate
Dec. 31, 2013
USD ($)
Dec. 31, 2013
CNY
Dec. 31, 2012
USD ($)
Dec. 31, 2012
CNY
Dec. 31, 2011
USD ($)
Dec. 31, 2011
CNY
Dec. 31, 2013
Cash-settled performance units [Member]
CNY
Dec. 31, 2012
Cash-settled performance units [Member]
CNY
Dec. 31, 2012
Equity-settled performance units [Member]
CNY
Sep. 30, 2013
Equity-settled performance units [Member]
Management [Member]
Sep. 30, 2013
Equity-settled performance units [Member]
Management [Member]
Annually Vesting [Member]
Sep. 30, 2013
Equity-settled performance units [Member]
Management [Member]
Vesting Depedent On Performance Targets [Member]
increments
Aug. 04, 2004
Expedia [Member]
USD ($)
Dec. 31, 2013
Expedia [Member]
Dec. 31, 2013
Minimum [Member]
Equity-settled performance units [Member]
Dec. 31, 2013
Maximum [Member]
Equity-settled performance units [Member]
Dec. 31, 2013
Ordinary shares [Member]
USD ($)
Dec. 31, 2013
ADS [Member]
USD ($)
Dec. 31, 2013
2001 Plan [Member]
Aug. 26, 2003
2001 Plan [Member]
Ordinary shares [Member]
Apr. 30, 2001
2001 Plan [Member]
Ordinary shares [Member]
Dec. 31, 2012
2004 Plan [Member]
Dec. 31, 2013
2004 Plan [Member]
Cash-settled performance units [Member]
Dec. 31, 2013
2004 Plan [Member]
Minimum [Member]
Dec. 31, 2013
2004 Plan [Member]
Maximum [Member]
Jul. 31, 2004
2004 Plan [Member]
Ordinary shares [Member]
Dec. 31, 2013
2009 Plan [Member]
Dec. 31, 2012
2009 Plan [Member]
Dec. 31, 2013
2009 Plan [Member]
Equity-settled performance units [Member]
Dec. 31, 2012
2009 Plan [Member]
Equity-settled performance units [Member]
Dec. 31, 2013
2009 Plan [Member]
Minimum [Member]
Dec. 31, 2013
2009 Plan [Member]
Maximum [Member]
Sep. 18, 2013
2009 Plan [Member]
Ordinary shares [Member]
Apr. 24, 2012
2009 Plan [Member]
Ordinary shares [Member]
Mar. 17, 2011
2009 Plan [Member]
Ordinary shares [Member]
May 31, 2009
2009 Plan [Member]
Ordinary shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                                                          
Shares available for grant                                         5,500,000 4,000,000         4,000,000             17,000,000 12,000,000 6,000,000 3,000,000
Stock option expiration period                                       10 years         5 years 10 years   5 years                  
Option to performance unit exchange ratio 0.8                                                                        
Vesting period for plan                   2 years   5 years       2 years 5 years               3 years 5 years           3 years 5 years        
Vesting increments                         3                                                
Fair value of options vested   $ 849,758 5,144,179   15,790,217   10,069,531                                                            
Options cancelled                                             302,762           1,158,984                
Price per share                                   $ 10.24 $ 20.48                                    
Intrinsic value of stock options exercised   3,000,000   1,600,000   15,300,000                                                              
Options granted                           711,429                                              
Options granted, exercise price                           $ 5.25                                              
Options exercised, forfeited or expired                             707,143                                            
Stock options outstanding                             4,286                                            
Accrued expenses and other current liabilities 198,970,866 55,817,679 337,903,480   198,970,866   127,803,167 1,574,681 892,697                                                        
Granted                   1,848,210 6,300,000                         32,004           6,566,627 1,169,406            
Incremental share-based compensation cost                   22,214,132                                                      
Fair value of performance units, vested     33,268,711   6,830,623   8,714,416                                                            
Cash paid to settle performance units     816,978   948,780   1,149,517                                                            
Unrecognized compensation cost related to non-vested stock options 70,657,237   297,229,308   70,657,237                                                                
Unrecognized compensation cost, recognition period   3 years 2 months 16 days 3 years 2 months 16 days