Income Taxes (Details) (USD $)				12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 State	Dec. 31, 2011 State Certain subsidiaries
Deferred tax assets:
Stock-based compensation expense	$ 37,752,000	$ 31,836,000
Accrued expenses	53,050,000	40,355,000
Deferred tax assets resulting from unrecognized tax benefits	12,231,000	10,371,000
State net operating losses	6,165,000	6,978,000	6,200,000
Accumulated other comprehensive loss	59,000	5,238,000
Gross deferred tax assets	109,257,000	94,778,000
Less valuation allowance	(3,160,000)	(3,166,000)
Net deferred tax assets	106,097,000	91,612,000
Deferred tax liabilities:
Property, plant and equipment	(123,525,000)	(105,751,000)
Intangibles	(117,842,000)	(95,227,000)
Net deferred tax liabilities	(241,367,000)	(200,978,000)
Net:	(135,270,000)	(109,366,000)
Reflected on consolidated balance sheets:
Current deferred tax assets, net	32,306,000	25,206,000
Noncurrent deferred tax liabilities, net	(167,576,000)	(134,572,000)
Net:	(135,270,000)	(109,366,000)
Operating loss carryforwards
Net operating loss carryforwards			143,900,000
Tax benefit associated with net operating loss carryforwards	6,165,000	6,978,000	6,200,000
Valuation allowance recorded to reflect the net operating losses which are not presently expected to be realized			3,200,000
Gross state net operating loss carryforwards for which no benefit has been recorded as they are attributable to uncertain tax positions				857,100,000
Unrecognized tax benefits attributable to the net operating losses				54,100,000
Increase to equity in the event of any benefit from realization of net operating losses				$ 8,900,000