CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accounts receivable, net of allowance for doubtful accounts of $2,124 and $4,495, respectively	$ 2,124	$ 4,495
Total assets of variable interest entities (in dollars)	142,300	152,400
Total liabilities of variable interest entities (in dollars)	$ 40,900	$ 35,600
Class A Common Stock
Common Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common Stock, shares authorized (in shares)	500,000,000	500,000,000
Common Stock, shares issued (in shares)	64,558,207	68,792,483
Common Stock, shares outstanding (in shares)	64,558,207	68,792,483
Class B Common Stock
Common Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common Stock, shares authorized (in shares)	140,000,000	140,000,000
Common Stock, shares issued (in shares)	25,760,684	25,928,357
Common Stock, shares outstanding (in shares)	25,760,684	25,928,357