Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data	Jun. 30, 2011	Dec. 31, 2010
Trade receivables, allowance for doubtful accounts	$ 4,181	$ 5,099
Prepaid expenses and other current assets	6,594	6,867
Intangible assets subject to amortization	25,536	26,615
Current maturities of long-term debt		1,000
Accounts payable and accrued expenses	39,925	38,550
Long-term debt, less current maturities, bond discount	4,602	4,881
Related Parties [Member]
Trade receivables, related parties	5,436	5,315
Prepaid expenses and other current assets	274	274
Intangible assets subject to amortization	24,360	25,880
Current maturities of long-term debt	0	1,000
Accounts payable and accrued expenses	$ 4,339	$ 4,683
Class A Common Stock [Member]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	260,000,000	260,000,000
Common stock, shares issued	53,514,769	52,978,304
Common stock, shares outstanding	53,514,769	52,978,304
Class B Common Stock [Member]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	22,188,161	22,188,161
Common stock, shares outstanding	22,188,161	22,188,161
Class U Common Stock [Member]
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