Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Accounts receivable, allowance for doubtful accounts (in dollars)	$ 0	$ 0
Class A Common Stock
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	106,644,576	105,007,873
Common stock, shares outstanding	106,644,576	105,007,873
Class B Common Stock
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