CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Accounts receivable, allowance for doubtful accounts	$ 4,357	$ 4,495
Total assets	147,454	152,373
Total liabilities of variable interest entities	$ 30,400	$ 35,600
Class A Common Stock
Common Stock, par value (USD per share)	$ 0.01	$ 0.01
Common Stock, shares authorized (shares)	500,000,000	500,000,000
Common Stock, shares issued (shares)	68,734,950	68,792,483
Common Stock, shares outstanding (shares)	68,734,950	68,792,483
Class B Common Stock
Common Stock, par value (USD per share)	$ 0.01	$ 0.01
Common Stock, shares authorized (shares)	140,000,000	140,000,000
Common Stock, shares issued (shares)	25,928,357	25,928,357
Common Stock, shares outstanding (shares)	25,928,357	25,928,357