Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Trade receivables, related parties	$ 6,172	$ 4,251
Trade receivables, allowance for doubtful accounts	3,790	2,890
Prepaid expenses and other current assets	18,021	11,557
Property and equipment, accumulated depreciation	191,183	188,579
Accumulated amortization of Intangible assets	103,752	99,819
Intangible assets subject to amortization, net	49,412	16,772
Accounts payable and accrued expenses	126,849	53,931
Unamortized debt issuance costs	1,796	2,226
Related Parties
Prepaid expenses and other current assets	274	274
Intangible assets subject to amortization, net	5,869	7,098
Accounts payable and accrued expenses	$ 2,087	$ 2,147
Class A common stock
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	260,000,000	260,000,000
Common stock, shares issued	60,759,405	60,074,698
Common stock, shares outstanding	60,759,405	60,074,698
Class B common stock
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	14,927,613	14,927,613
Common stock, shares outstanding	14,927,613	14,927,613
Class U common stock
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	9,352,729	9,352,729
Common stock, shares outstanding	9,352,729	9,352,729