Consolidated Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2011	Dec. 31, 2010
Accounts receivable, allowance for doubtful accounts (in dollars)	$ 0	$ 0
Common Class A
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, Authorized shares	150,000,000	150,000,000
Common stock, shares issued	83,116,779	81,331,737
Common stock, shares outstanding	83,116,779	81,331,737
Common Class B
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, Authorized shares	13,000,000	13,000,000
Common stock, shares issued	35,556	35,556
Common stock, shares outstanding	35,556	35,556