Condensed Consolidated Balance Sheets (Parenthetical) (USD $)
Mar. 31, 2015
Dec. 31, 2014
Statement of Financial Position [Abstract]    
Preferred Stock, par value (in usd per share) $ 0.001 $ 0.001
Preferred Stock, shares authorized 5,000,000 5,000,000
Preferred Stock, shares issued 0 0
Preferred Stock, shares outstanding 0 0
Common Stock, par value (in usd per share) $ 0.001 $ 0.001
Common Stock, shares authorized 250,000,000 250,000,000
Common Stock, shares issued 130,955,000 130,627,000
Common Stock, shares outstanding 88,764,000 91,729,000
Treasury Stock, shares (42,191,000) (38,898,000)