Consolidated Balance Sheets Parenthetical (USD $)	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010
Consolidated Balance Sheets Parenthetical [Abstract]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Common stock, authorized (in shares)	100,000,000	100,000,000	100,000,000
Common stock, shares issued (in shares)	48,253,576	49,381,678	49,548,424
Common stock, outstanding (in shares)	48,253,576	49,278,578	49,548,424