Income Taxes (Details 1) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Current deferred income tax assets:
Accounts receivable	$ 5,362	$ 4,996
State taxes	4,469	5,329
Other liabilities and reserves	8,112	6,528
Other assets	7,046	904
Inventory	1,321	1,262
Total current deferred income tax assets	26,310	19,019
Non-current deferred income tax (liabilities) assets:
Net operating loss carryforwards	29,362	31,377
Write-down of assets	1,222	1,216
Start-up costs	335	333
Other assets	31,306	25,826
Intangible assets	(128,947)	(113,685)
Property and equipment	(27,131)	(19,105)
Unrealized loss on investments	1,961	1,950
Share-based compensation	6,416	6,115
Valuation allowance	(15,753)	(16,158)
Total non-current deferred income tax liabilities, net	$ (101,229)	$ (82,131)