Condensed Consolidated Balance Sheets (Parenthetical) (USD $)
Mar. 31, 2014
Dec. 31, 2013
Statement of Financial Position [Abstract]    
Common stock, par value per share $ 0.01 $ 0.01
Common stock, shares issued 370,949,721 370,570,565
Common stock, shares outstanding 370,732,369 370,363,803