Segment Information Segments (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) reportable_segment provinces region	Sep. 30, 2016 USD ($)	Dec. 01, 2016
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	$ 400,735	$ 349,807	$ 1,161,635	$ 1,017,003
Freight-related revenues	140,923	129,520	387,881	396,666
All other revenues	35,269	21,675	86,952	71,324
Total Operating revenues	576,927	501,002	1,636,468	1,484,993
Operating Income (Loss)	111,489	91,851	290,283	236,041
Depreciation and amortization	64,222	50,841	186,509	151,095
Interest expense, net	27,818	16,917	79,160	52,222
Provision for/(benefit from) income taxes	30,507	19,643	82,032	54,563
Expenditures for Additions to Property and Equipment Net of Grants From Outside Parties	53,239	42,240	$ 133,107	129,571
North American Operations [Member]
Segment Reporting Information [Line Items]
Number of operating regions | provinces			7
Freight revenues	242,968	232,247	$ 719,622	681,154
Freight-related revenues	60,286	62,124	186,814	184,627
All other revenues	15,673	15,823	47,641	48,766
Total Operating revenues	318,927	310,194	954,077	914,547
Operating Income (Loss)	82,111	87,153	229,267	236,154
Depreciation and amortization	40,036	37,085	117,822	110,398
Interest expense, net	9,817	9,600	29,928	29,730
Provision for/(benefit from) income taxes	28,270	22,392	78,133	59,354
Expenditures for Additions to Property and Equipment Net of Grants From Outside Parties	41,713	30,343	105,940	95,282
Australian Operations [Member]
Segment Reporting Information [Line Items]
Freight revenues	66,404	29,219	191,031	80,390
Freight-related revenues	12,880	23,523	36,089	76,142
All other revenues	1,986	1,408	4,866	4,699
Total Operating revenues	81,270	54,150	231,986	161,231
Operating Income (Loss)	22,276	4,372	59,685	2,002
Depreciation and amortization	15,753	7,129	45,915	21,018
Interest expense, net	13,678	2,170	41,500	6,963
Provision for/(benefit from) income taxes	2,013	798	4,805	521
Expenditures for Additions to Property and Equipment Net of Grants From Outside Parties	4,545	2,440	9,721	8,094
U.K./European Operations [Member]
Segment Reporting Information [Line Items]
Freight revenues	91,363	88,341	250,982	255,459
Freight-related revenues	67,757	43,873	164,978	135,897
All other revenues	17,610	4,444	34,445	17,859
Total Operating revenues	176,730	136,658	450,405	409,215
Operating Income (Loss)	7,102	326	1,331	(2,115)
Depreciation and amortization	8,433	6,627	22,772	19,679
Interest expense, net	4,323	5,147	7,732	15,529
Provision for/(benefit from) income taxes	224	(3,547)	(906)	(5,312)
Expenditures for Additions to Property and Equipment Net of Grants From Outside Parties	$ 6,981	$ 9,457	$ 17,446	$ 26,195
MIRA [Member]
Segment Reporting Information [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners					48.90%