Changes in Operations Europe - Freightliner (Details) £ in Thousands, $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($) $ / £	Mar. 31, 2015 GBP (£)	Mar. 31, 2015 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($) $ / £	Mar. 25, 2015 GBP (£) employee rail_car locomotive $ / £	Mar. 25, 2015 USD ($) employee rail_car locomotive $ / £
Foreign currency exchange rate | $ / £		1.51				1.51	1.49	1.49
Operating revenues	$ 501,002	$ 546,299			$ 1,484,993	$ 1,485,548
Operating income	91,851	117,559			236,041	289,630
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	$ 0	0			$ 0	18,686
Freightliner [Member]
Business Acquisition, Effective Date of Acquisition			Mar. 25, 2015	Mar. 25, 2015
Business Acquisition, Percentage of Voting Interests Acquired							100.00%	100.00%
Business Acquisition, Name of Acquired Entity			Freightliner Group Limited (Freightliner)	Freightliner Group Limited (Freightliner)
Percentage of economic interest retained by acquiree's management			6.00%	6.00%
Number of employees | employee							2,500	2,500
Diesel Locomotives | locomotive							250	250
Electric locomotives | locomotive							45	45
Railcars | rail_car							5,500	5,500
Cash consideration			£ 492,083	$ 733,006
Deferred consideration			24,200	36,048
Total consideration			£ 516,283	$ 769,054
Contingent liability							£ 24,200	$ 36,000
Operating revenues						363,500
Operating income						21,400
Acquisition-related costs		$ 700				$ 14,000