Consolidated Statements of Operations (unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues [Abstract]
Revenues	$ 604.8	$ 533.2
Cost of revenues:
Total cost of revenues	463.4	399.9
Selling, engineering, and administrative expenses:
Selling, engineering, and administrative expenses	59.6	73.4
Gains on dispositions of property:
Net gains on railcar lease fleet sales owned more than one year at the time of sale	7.9	2.1
Other	2.1	0.1
Total gains (losses) on disposition of property	10.0	2.2
Total operating profit	91.8	62.1
Other (income) expense:
Interest income	(1.3)	(3.9)
Interest expense	52.7	46.3
Other, net	(0.3)	1.2
Other Nonoperating Expense	51.7	41.2
Income from continuing operations before income taxes	40.1	20.9
Provision for income taxes	8.9	5.7
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	31.2	15.2
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(1.1)	26.4
Net income	30.1	41.6
Net income (loss) attributable to noncontrolling interest	(0.5)	1.4
Net income attributable to Trinity Industries, Inc.	$ 30.6	$ 40.2
Basic earnings per common share:
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.24	$ 0.09
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	(0.01)	0.18
Basic (in dollars per share)	0.23	0.27
Income (Loss) from Continuing Operations, Per Diluted Share	0.24	0.09
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	(0.01)	0.17
Diluted (in dollars per share)	$ 0.23	$ 0.26
Weighted average number of shares outstanding:
Basic (in shares)	130.4	147.4
Diluted (in shares)	132.2	153.7
Manufacturing
Revenues [Abstract]
Revenues	$ 404.6	$ 358.9
Cost of revenues:
Total cost of revenues	351.6	306.5
Selling, engineering, and administrative expenses:
Selling, engineering, and administrative expenses	23.2	23.5
Leasing
Revenues [Abstract]
Revenues	200.2	174.3
Cost of revenues:
Total cost of revenues	111.8	93.4
Selling, engineering, and administrative expenses:
Selling, engineering, and administrative expenses	12.8	12.2
Other
Selling, engineering, and administrative expenses:
Selling, engineering, and administrative expenses	$ 23.6	$ 37.7