Property and Equipment and Leases Property and Equipment (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Gross Book Value	$ 5,863,487,000	$ 5,479,665,000
Accumulated Depreciation	(1,206,566,000)	(976,346,000)
Net Book Value	4,656,921,000	4,503,319,000
Depreciation expense	192,900,000	172,300,000	$ 159,100,000
Land and land improvements
Property, Plant and Equipment [Line Items]
Gross Book Value	755,234,000	735,054,000
Accumulated Depreciation	0	0
Net Book Value	755,234,000	735,054,000
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Gross Book Value	257,173,000	214,980,000
Accumulated Depreciation	(59,611,000)	(43,431,000)
Net Book Value	197,562,000	171,549,000
Bridges/tunnels/culverts
Property, Plant and Equipment [Line Items]
Gross Book Value	718,001,000	692,324,000
Accumulated Depreciation	(122,380,000)	(103,521,000)
Net Book Value	595,621,000	588,803,000
Track property
Property, Plant and Equipment [Line Items]
Gross Book Value	2,758,946,000	2,639,961,000
Accumulated Depreciation	(568,954,000)	(477,366,000)
Net Book Value	2,189,992,000	2,162,595,000
Total property
Property, Plant and Equipment [Line Items]
Gross Book Value	4,489,354,000	4,282,319,000
Accumulated Depreciation	(750,945,000)	(624,318,000)
Net Book Value	3,738,409,000	3,658,001,000
Computer equipment
Property, Plant and Equipment [Line Items]
Gross Book Value	24,070,000	20,449,000
Accumulated Depreciation	(17,852,000)	(14,927,000)
Net Book Value	6,218,000	5,522,000
Locomotives and railcars
Property, Plant and Equipment [Line Items]
Gross Book Value	993,872,000	893,911,000
Accumulated Depreciation	(290,796,000)	(217,704,000)
Net Book Value	703,076,000	676,207,000
Vehicles and mobile equipment
Property, Plant and Equipment [Line Items]
Gross Book Value	77,928,000	72,388,000
Accumulated Depreciation	(48,147,000)	(41,257,000)
Net Book Value	29,781,000	31,131,000
Signals and crossing equipment
Property, Plant and Equipment [Line Items]
Gross Book Value	75,460,000	72,210,000
Accumulated Depreciation	(42,079,000)	(37,632,000)
Net Book Value	33,381,000	34,578,000
Track equipment
Property, Plant and Equipment [Line Items]
Gross Book Value	88,629,000	48,931,000
Accumulated Depreciation	(18,873,000)	(15,663,000)
Net Book Value	69,756,000	33,268,000
Other equipment
Property, Plant and Equipment [Line Items]
Gross Book Value	77,271,000	57,547,000
Accumulated Depreciation	(37,874,000)	(24,845,000)
Net Book Value	39,397,000	32,702,000
Total equipment
Property, Plant and Equipment [Line Items]
Gross Book Value	1,337,230,000	1,165,436,000
Accumulated Depreciation	(455,621,000)	(352,028,000)
Net Book Value	881,609,000	813,408,000
Construction-in-process [Member]
Property, Plant and Equipment [Line Items]
Gross Book Value	36,903,000	31,910,000
Accumulated Depreciation	0	0
Net Book Value	36,903,000	31,910,000
Australian Operations [Member]
Property, Plant and Equipment [Line Items]
Net Book Value	664,367,000	634,148,000
Asset Impairment Charges	$ (5,900,000)	$ (13,000,000)