Consolidated Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2011	Dec. 31, 2010
Stockholders' Equity:
Preferred stock, par value per share	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value per share	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	85,000,000
Common stock, shares issued	42,946,570	42,440,583
Common stock, shares outstanding	42,465,727	41,999,058
Treasury stock shares held, at cost	480,843	441,525