ORGANIZATION AND BASIS OF PRESENTATION (Details)	May 30, 2007 $ / shares shares
Common Class A [Member]
Class of Stock [Line Items]
Shares issued from initial public offering | shares	11,787,500
Price per share of shares issued from initial public offering | $ / shares	$ 19.00
Common Class B
Class of Stock [Line Items]
Shares issued from initial public offering | shares	2,631,579
Price per share of shares issued from initial public offering | $ / shares	$ 19.00