Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Class A Common Stock [Member]	Dec. 31, 2012 Class A Common Stock [Member]	Mar. 31, 2013 Class B Common Stock [Member]	Dec. 31, 2012 Class B Common Stock [Member]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Common stock, par value			$ 0.01	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized			100,000,000	100,000,000	900,000,000	900,000,000
Common stock, shares issued			11,657,563	11,657,563	4,512,225	4,465,725
Common stock, shares outstanding			11,657,563	11,657,563	4,512,225	4,465,725