Consolidated Balance Sheets Parenthetical - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Allowance for doubtful accounts		$ 12,504	$ 5,543
Preferred stock par value (usd per share)		$ 0.001	$ 0.001
Preferred stock authorized for issuance, shares		40,000,000	40,000,000
Preferred stock, shares issued		0	0
Preferred stock, shares outstanding		0	0
Treasury stock issued, shares		14,102,453	7,670,216
Assets	[1]	$ 9,401,051	$ 9,708,863
Liabilities	[1]	$ 5,855,368	$ 5,877,141
Common Class A
Common stock par value (usd per share)		$ 0.001	$ 0.001
Common stock authorized for issuance, shares		1,000,000,000	1,000,000,000
Common stock issued, shares		100,416,516	100,015,546
Common stock outstanding, shares		86,314,063	92,345,330
Common Class B
Common stock par value (usd per share)		$ 0.001	$ 0.001
Common stock authorized for issuance, shares		1,000,000,000	1,000,000,000
Common stock issued, shares		5,605	5,605
Common stock outstanding, shares		5,605	5,605
Current | Senior Secured Credit Agreement | Term Loan Facility
Debt instrument, unamortized discount and debt issuance costs		$ 7,917	$ 7,979
Noncurrent | Senior Secured Credit Agreement | Term Loan Facility
Debt instrument, unamortized discount and debt issuance costs		38,830	48,809
Variable Interest Entity, Primary Beneficiary
Assets		97,000	108,000
Liabilities		$ 3,000	$ 3,000

[1] The Company’s consolidated total assets as of December 31, 2016 and December 31, 2015 include total assets of variable interest entities (“VIEs”) of $97 million and $108 million, respectively, which can only be used to settle the obligations of the VIEs. The Company’s consolidated total liabilities as of December 31, 2016 and December 31, 2015 include total liabilities of the VIEs of $3 million and $3 million, respectively, for which the creditors of the VIEs have no recourse to the Company (see Note 1).