Property and Equipment and Leases (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 2,008,179	$ 1,747,458
Less: accumulated depreciation	(364,590)	(303,281)
Property and equipment, net	1,643,589	1,444,177
Construction-in-process
Property, Plant and Equipment [Line Items]
Total property and equipment	68,188	33,540
Computer equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	5,381	5,072
Locomotives and rail cars
Property, Plant and Equipment [Line Items]
Total property and equipment	265,167	225,598
Vehicles and mobile equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	31,460	28,132
Signals and crossing equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	27,813	23,090
Track equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	9,868	9,395
Other equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	20,206	13,723
Total Equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	359,895	305,010
Land and land improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	147,176	129,541
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	60,362	55,721
Bridges/tunnels/culverts
Property, Plant and Equipment [Line Items]
Total property and equipment	224,227	192,006
Track property
Property, Plant and Equipment [Line Items]
Total property and equipment	1,148,331	1,031,640
Total Property
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 1,580,096	$ 1,408,908