Segment Information Segments (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) reportable_segment provinces region	Mar. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of operating regions | region	9
Number of reportable segments | reportable_segment	3
Noncontrolling Interest, Ownership Percentage by Parent	51.10%
Freight revenues	$ 399,639	$ 377,745
Freight-related revenues	141,197	119,337
All other revenues	33,825	22,026
Total Operating revenues	574,661	519,108
Operating Income (Loss)	86,913	75,900
Depreciation and amortization	65,990	60,774
Interest expense, net	24,738	26,138
Provision for/(benefit from) income taxes	(15,890)	21,928
Expenditures for Additions to Property and Equipment Net of Grants From Outside Parties	$ 52,288	29,967
North American Operations [Member]
Segment Reporting Information [Line Items]
Number of operating regions | provinces	7
Freight revenues	$ 245,417	238,281
Freight-related revenues	63,832	65,345
All other revenues	16,381	15,850
Total Operating revenues	325,630	319,476
Operating Income (Loss)	73,160	67,663
Depreciation and amortization	40,631	38,867
Interest expense, net	8,455	10,551
Provision for/(benefit from) income taxes	(19,485)	22,074
Expenditures for Additions to Property and Equipment Net of Grants From Outside Parties	38,563	24,215
Australian Operations [Member]
Segment Reporting Information [Line Items]
Freight revenues	63,011	60,874
Freight-related revenues	10,563	11,709
All other revenues	1,260	1,324
Total Operating revenues	74,834	73,907
Operating Income (Loss)	15,976	17,159
Depreciation and amortization	16,007	15,192
Interest expense, net	13,241	13,987
Provision for/(benefit from) income taxes	821	861
Expenditures for Additions to Property and Equipment Net of Grants From Outside Parties	5,262	1,462
U.K./European Operations [Member]
Segment Reporting Information [Line Items]
Freight revenues	91,211	78,590
Freight-related revenues	66,802	42,283
All other revenues	16,184	4,852
Total Operating revenues	174,197	125,725
Operating Income (Loss)	(2,223)	(8,922)
Depreciation and amortization	9,352	6,715
Interest expense, net	3,042	1,600
Provision for/(benefit from) income taxes	2,774	(1,007)
Expenditures for Additions to Property and Equipment Net of Grants From Outside Parties	$ 8,463	$ 4,290
MIRA [Member]
Segment Reporting Information [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	48.90%