Fair Value Measurements (Details 2) (Redeemable Non-Controlling Interest, Fair value measurement on a recurring basis, Significant Unobservable Inputs (Level 3))
3 Months Ended
Mar. 31, 2015
Redeemable Non-Controlling Interest | Fair value measurement on a recurring basis | Significant Unobservable Inputs (Level 3)
 
Assets and liabilities measured at fair value on a non-recurring basis  
Fair value inputs, discount rate 15.50%