Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Trade receivables, allowance for doubtful accounts	$ 2,962	$ 3,100
Trade receivables, related parties	1,140	10,882
Prepaid expenses and other current assets	5,776	5,295
Property and equipment, accumulated depreciation	196,590	193,532
Accumulated amortization of Intangible assets	75,581	74,697
Intangible assets subject to amortization, net	19,309	20,193
Accounts payable and accrued expenses	27,432	32,195
Related Parties
Prepaid expenses and other current assets	274	274
Intangible assets subject to amortization, net	15,658	16,239
Accounts payable and accrued expenses	$ 3,847	$ 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	63,500,483	58,893,970
Common stock, shares outstanding	63,500,483	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