Property and Equipment (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Plant and equipment
Property and equipment	$ 4,104,151,000		$ 4,104,151,000		$ 4,014,770,000
Less accumulated depreciation	(1,426,148,000)		(1,426,148,000)		(1,283,973,000)
Property and equipment, net	2,678,003,000		2,678,003,000		2,730,797,000
Depreciation expense	75,500,000	56,700,000	151,700,000	109,900,000
Interest capitalized in connection with major construction projects	300,000	3,000,000	400,000	5,900,000
Land and improvements
Plant and equipment
Property and equipment	438,648,000		438,648,000		442,882,000
Building and improvements
Plant and equipment
Property and equipment	2,312,637,000		2,312,637,000		2,283,230,000
Furniture, fixtures and equipment
Plant and equipment
Property and equipment	1,290,690,000		1,290,690,000		1,240,898,000
Leasehold improvements
Plant and equipment
Property and equipment	17,188,000		17,188,000		17,229,000
Construction in progress
Plant and equipment
Property and equipment	$ 44,988,000		$ 44,988,000		$ 30,531,000