Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0	$ 0
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.06	$ 0.06
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	145,578,023	143,076,357
Common stock, shares outstanding (in shares)	145,578,023	143,076,357