Property and Equipment (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Plant and equipment
Property and equipment	$ 3,203,378,000		$ 3,203,378,000		$ 2,895,094,000
Less accumulated depreciation	(1,023,641,000)		(1,023,641,000)		(929,320,000)
Property and equipment, net	2,179,737,000		2,179,737,000		1,965,774,000
Depreciation expense	53,400,000	50,900,000	105,800,000	100,400,000
Interest capitalized in connection with major construction projects	1,000,000	1,700,000	1,800,000	2,800,000
Property and equipment increase, total, due primarily to acquisition			308,300,000
Land and improvements
Plant and equipment
Property and equipment	392,725,000		392,725,000		298,482,000
Building and improvements
Plant and equipment
Property and equipment	1,705,418,000		1,705,418,000		1,534,117,000
Furniture, fixtures and equipment
Plant and equipment
Property and equipment	993,142,000		993,142,000		938,443,000
Leasehold improvements
Plant and equipment
Property and equipment	17,151,000		17,151,000		17,089,000
Construction in progress
Plant and equipment
Property and equipment	$ 94,942,000		$ 94,942,000		$ 106,963,000