Segment Information - Segment Financial Information (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Total sales	$ 1,593,617	$ 1,056,177
Income (loss) from operations	67,307	131,279
Interest expense and other, net	(52,797)	(17,698)
Income from operations before income taxes	14,510	113,581
Freight Segment
Segment Reporting Information [Line Items]
Total sales	876,434	379,554
Transit Segment
Segment Reporting Information [Line Items]
Total sales	717,183	676,623
Corporate Activities and Elimination
Segment Reporting Information [Line Items]
Total sales	(22,826)	(15,891)
Income (loss) from operations	(66,836)	(6,427)
Interest expense and other, net	(52,797)	(17,698)
Income from operations before income taxes	(119,633)	(24,125)
Corporate Activities and Elimination \| Freight Segment
Segment Reporting Information [Line Items]
Total sales	16,704	12,002
Corporate Activities and Elimination \| Transit Segment
Segment Reporting Information [Line Items]
Total sales	6,122	3,889
Operating Segments \| Freight Segment
Segment Reporting Information [Line Items]
Total sales	893,138	391,556
Income (loss) from operations	75,210	69,623
Interest expense and other, net	0	0
Income from operations before income taxes	75,210	69,623
Operating Segments \| Transit Segment
Segment Reporting Information [Line Items]
Total sales	723,305	680,512
Income (loss) from operations	58,933	68,083
Interest expense and other, net	0	0
Income from operations before income taxes	$ 58,933	$ 68,083

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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