Changes in Operations United Kingdom - Pentalver (Details) £ in Thousands, $ in Thousands			3 Months Ended		9 Months Ended
	May 03, 2017 GBP (£) a employee seaport truck $ / AUD	May 03, 2017 USD ($) a seaport	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($) $ / AUD	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($) $ / AUD	May 03, 2017 USD ($) employee truck $ / AUD	Dec. 31, 2016 USD ($)	Dec. 01, 2016 $ / AUD
Payments to Acquire Businesses, Net of Cash Acquired					$ 107,586	$ 0
Foreign currency exchange rate | $ / AUD	1.29			0.74		0.74	1.29		0.74
Operating Income			$ 111,489	$ 91,851	290,283	$ 236,041
Depreciation and amortization			64,222	$ 50,841	186,509	$ 151,095
Goodwill			$ 1,187,189		1,187,189			$ 1,125,596
Pentalver Transport Limited [Member]
Business Acquisition, Percentage of Voting Interests Acquired	100.00%						100.00%
Business Acquisition, Effective Date of Acquisition	May 03, 2017	May 03, 2017
Payments to Acquire Businesses, Gross	£ 97,800	$ 126,200
Payments to Acquire Businesses, Net of Cash Acquired	77,500	100,100
Cash Acquired from Acquisition	£ 20,200	$ 26,100
Number of Major Seaports | seaport	4	4
Number of trucks | truck	150						150
Number of employees | employee	600						600
Revenues					64,700
Operating Income					3,100
Depreciation and amortization					2,100
Acquisition and integration related costs					3,700
Cash and cash equivalents	£ 20,224						$ 26,117
Accounts receivable	16,847						21,756
Materials and supplies	13,360						17,253
Prepaid expenses and other	3,238						4,182
Property and equipment	22,403						28,931
Goodwill	9,368						12,098
Total Assets	126,440						163,284
Accounts payable and accrued expenses	21,214						27,396
Deferred income tax liabilities, net	6,876						8,880
Deferred items-grants from outside parties	601						776
Net assets	£ 97,749						$ 126,232
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	33 years	33 years
Minimum [Member] | Pentalver Transport Limited [Member]
Number of Acres Providing Storage for Loaded and Empty Containers | a	100	100
Maximum [Member] | Pentalver Transport Limited [Member]
Term of contract of operational rights, in years	50 years	50 years
Freightliner [Member]
Number of trucks | truck	200						200
Operational Network Rights [Member] | Pentalver Transport Limited [Member]
Finite-lived Intangible Assets Acquired	£ 41,000	$ 52,947
Other Expense [Member] | Pentalver Transport Limited [Member]
Acquisition and integration related costs					3,600
Labor and Benefits [Member] | Pentalver Transport Limited [Member]
Acquisition and integration related costs					$ 100