Condensed Consolidated Balance Sheets (Parenthetical) (USD $)
Mar. 31, 2015
Dec. 31, 2014
Statement of Financial Position [Abstract]    
Common stock, par value $ 0.01 $ 0.01
Common stock, shares authorized 260,000,000 260,000,000
Common stock, shares issued 214,179,000 213,791,000
Treasury Stock, Shares 1,517,000 1,517,000