Condensed Consolidating Financial Statements (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011
Current assets
Cash and cash equivalents	$ 32,315	$ 36,130	$ 51,169	$ 58,719
Trade receivables, net of allowance for doubtful accounts	46,361	48,030
Prepaid expenses and other current assets	4,960	4,245
Total current assets	83,636	88,405
Property and equipment, net	60,042	61,435
Intangible assets subject to amortization, net	21,714	22,349
Intangible assets not subject to amortization	220,701	220,701
Goodwill	36,647	36,647
Other assets	8,072	8,514
Total assets	430,812	438,051
Current liabilities
Current maturities of long-term debt	200	150
Advances payable, related parties	118	118
Accounts payable and accrued expenses	29,855	39,158
Total current liabilities	30,173	39,426
Long-term debt, less current maturities	340,748	340,664
Other long-term liabilities	7,180	7,359
Deferred income taxes	47,043	45,201
Total liabilities	425,144	432,650
Stockholders' equity
Member's capital
Additional paid-in capital	932,037	930,814
Accumulated deficit	(926,378)	(925,421)
Total stockholders' equity	5,668	5,401
Total liabilities and stockholders' equity	430,812	438,051
Class A Common Stock [Member]
Stockholders' equity
Common stock	6	5
Class B Common Stock [Member]
Stockholders' equity
Common stock	2	2
Class U common stock [Member]
Stockholders' equity
Common stock	1	1
Parent [Member]
Current assets
Cash and cash equivalents	31,868	35,631	50,658	58,276
Trade receivables, net of allowance for doubtful accounts	45,989	47,779
Prepaid expenses and other current assets	4,320	3,778
Total current assets	82,177	87,188
Property and equipment, net	57,454	58,900
Intangible assets subject to amortization, net	21,714	22,349
Intangible assets not subject to amortization	38,739	38,739
Goodwill	35,653	35,653
Investment in subsidiaries	162,651	164,355
Other assets	8,072	8,514
Total assets	406,460	415,698
Current liabilities
Current maturities of long-term debt	200	150
Advances payable, related parties	118	118
Accounts payable and accrued expenses	38,117	47,537
Total current liabilities	38,435	47,805
Long-term debt, less current maturities	340,748	340,664
Other long-term liabilities	7,180	7,359
Deferred income taxes	14,429	14,469
Total liabilities	400,792	410,297
Stockholders' equity
Member's capital
Additional paid-in capital	932,037	930,814
Accumulated deficit	(926,378)	(925,421)
Total stockholders' equity	5,668	5,401
Total liabilities and stockholders' equity	406,460	415,698
Parent [Member] | Class A Common Stock [Member]
Stockholders' equity
Common stock	6	5
Parent [Member] | Class B Common Stock [Member]
Stockholders' equity
Common stock	2	2
Parent [Member] | Class U common stock [Member]
Stockholders' equity
Common stock	1	1
Guarantor Subsidiaries [Member]
Current assets
Intangible assets not subject to amortization	178,262	178,262
Total assets	178,262	178,262
Current liabilities
Deferred income taxes	34,001	32,214
Total liabilities	34,001	32,214
Stockholders' equity
Member's capital	804,654	804,654
Additional paid-in capital	(660,393)
Accumulated deficit		(658,606)
Total stockholders' equity	144,261	146,048
Total liabilities and stockholders' equity	178,262	178,262
Non-Guarantor Subsidiaries [Member]
Current assets
Cash and cash equivalents	447	499	511	443
Trade receivables, net of allowance for doubtful accounts	372	251
Prepaid expenses and other current assets	640	467
Total current assets	1,459	1,217
Property and equipment, net	2,588	2,535
Intangible assets not subject to amortization	3,700	3,700
Goodwill	994	994
Other assets	10,396	10,603
Total assets	19,137	19,049
Current liabilities
Accounts payable and accrued expenses	747	742
Total current liabilities	747	742
Total liabilities	747	742
Stockholders' equity
Member's capital	12,652	12,652
Additional paid-in capital	5,738
Accumulated deficit		5,655
Total stockholders' equity	18,390	18,307
Total liabilities and stockholders' equity	19,137	19,049
Eliminations [Member]
Current assets
Investment in subsidiaries	(162,651)	(164,355)
Other assets	(10,396)	(10,603)
Total assets	(173,047)	(174,958)
Current liabilities
Accounts payable and accrued expenses	(9,009)	(9,121)
Total current liabilities	(9,009)	(9,121)
Deferred income taxes	(1,387)	(1,482)
Total liabilities	(10,396)	(10,603)
Stockholders' equity
Member's capital	(817,306)	(817,306)
Additional paid-in capital	654,655
Accumulated deficit		652,951
Total stockholders' equity	(162,651)	(164,355)
Total liabilities and stockholders' equity	$ (173,047)	$ (174,958)