Unaudited Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares
Mar. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Preferred stock, par value per share $ 0.01 $ 0.01  
Preferred stock, shares authorized 150,000,000 150,000,000  
Preferred stock, shares issued 0 0  
Preferred stock, shares outstanding 0 0  
Common Stock, Par or Stated Value Per Share $ 0.01 $ 0.01 $ 0.01
Common stock, shares authorized 1,500,000,000 1,500,000,000 1,500,000,000
Common stock, shares, issued 196,221,296 196,216,596 195,743,154
Common stock, shares, outstanding 196,221,296 196,216,596 195,743,154