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Changes in Operations U.K./Europe Optimization Restructuring Reserve Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring and related costs	$ 7,634	$ 283
U.K. Operations Optimization [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	5,329		$ 5,329	$ 5,076
Restructuring and related costs	5,496		20,480
Payments for Restructuring	(5,243)
Restructuring Reserve, Settled without Cash	0
Rationalization of locomotive and railcar fleet [Member] \| U.K. Operations Optimization [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	3,742		3,742	4,094
Restructuring and related costs	0		6,301
Payments for Restructuring	(352)
Restructuring Reserve, Settled without Cash	0
Management restructuring [Member] \| U.K. Operations Optimization [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	1,587		1,587	982
Restructuring and related costs	4,083		8,723
Payments for Restructuring	(3,478)
Restructuring Reserve, Settled without Cash	0
Productivity and automation investments [Member] \| U.K. Operations Optimization [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	0		0	$ 0
Restructuring and related costs	1,413		$ 5,456
Payments for Restructuring	(1,413)
Restructuring Reserve, Settled without Cash	$ 0