Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Trade receivables, allowance for doubtful accounts	$ 3,040	$ 3,100
Trade receivables, related parties	5,534	10,882
Prepaid expenses and other current assets	5,705	5,295
Property and equipment, accumulated depreciation	198,282	193,532
Accumulated amortization of Intangible assets	78,234	74,697
Intangible assets subject to amortization, net	16,656	20,193
Accounts payable and accrued expenses	29,669	32,195
Related Parties
Prepaid expenses and other current assets	274	274
Intangible assets subject to amortization, net	13,918	16,239
Accounts payable and accrued expenses	$ 3,791	$ 3,695
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	64,477,171	58,893,970
Common stock, shares outstanding	64,477,171	58,893,970
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	18,930,035
Common stock, shares outstanding	14,927,613	18,930,035
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