Supplemental Cash Flow Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock issued for acquisition (value)	$ 14.7
Net cost of sold lease fleet railcars owned one year or less	79.9	$ 92.0	$ 295.9
Interest paid	151.2	151.0	164.3
Income tax payments made, net	$ (77.8)	$ (57.9)	$ 326.8
Lightweight Aggregates Business | Construction Products Group
Stock issued for acquisition (shares)	459,603
Stock issued for acquisition (value)	$ 14.7