Consolidated Statements of Operations (unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues [Abstract]
Revenues	$ 736.0	$ 634.0	$ 1,340.8	$ 1,167.2
Cost of revenues:
Total cost of revenues	578.5	481.9	1,041.9	881.8
Selling, engineering, and administrative expenses:
Selling, engineering, and administrative expenses	69.8	75.6	129.4	149.0
Gains on dispositions of property:
Net gains on railcar lease fleet sales owned more than one year at the time of sale	18.7	9.5	26.6	11.6
Other	0.6	2.0	2.7	2.1
Total gains (losses) on disposition of property	19.3	11.5	29.3	13.7
Total operating profit	107.0	88.0	198.8	150.1
Other (income) expense:
Interest income	(1.6)	(3.7)	(2.9)	(7.6)
Interest expense	57.0	43.8	109.7	90.1
Other, net	0.1	1.9	(0.2)	3.1
Other Nonoperating Expense	55.3	38.2	107.0	79.4
Income from continuing operations before income taxes	51.7	49.8	91.8	70.7
Provision for income taxes	14.1	12.5	23.0	18.2
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	37.6	37.3	68.8	52.5
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(0.8)	28.2	(1.9)	54.6
Net income	36.8	65.5	66.9	107.1
Net income (loss) attributable to noncontrolling interest	0.4	1.4	(0.1)	2.8
Net income attributable to Trinity Industries, Inc.	$ 36.4	$ 64.1	$ 67.0	$ 104.3
Basic earnings per common share:
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.29	$ 0.24	$ 0.53	$ 0.33
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	(0.01)	0.19	(0.02)	0.37
Basic (in dollars per share)	0.28	0.43	0.51	0.70
Income (Loss) from Continuing Operations, Per Diluted Share	0.29	0.24	0.52	0.32
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	(0.01)	0.19	(0.01)	0.36
Diluted (in dollars per share)	$ 0.28	$ 0.43	$ 0.51	$ 0.68
Weighted average number of shares outstanding:
Basic (in shares)	127.6	146.2	129.0	146.7
Diluted (in shares)	129.2	147.0	130.7	150.2
Manufacturing
Revenues [Abstract]
Revenues	$ 459.1	$ 420.8	$ 863.7	$ 779.7
Cost of revenues:
Total cost of revenues	399.6	363.4	751.2	669.9
Selling, engineering, and administrative expenses:
Selling, engineering, and administrative expenses	26.5	23.1	49.7	46.6
Leasing
Revenues [Abstract]
Revenues	276.9	213.2	477.1	387.5
Cost of revenues:
Total cost of revenues	178.9	118.5	290.7	211.9
Selling, engineering, and administrative expenses:
Selling, engineering, and administrative expenses	12.7	12.6	25.5	24.8
Other
Selling, engineering, and administrative expenses:
Selling, engineering, and administrative expenses	$ 30.6	$ 39.9	$ 54.2	$ 77.6