EARNINGS PER SHARE - Reconciliation of Components of Basic and Diluted Earnings Per Share (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Numerator for basic and diluted earnings per share:
Income from continuing operations attributable to U.S. Concrete									$ 14.9	$ 30.0	$ 26.1
Loss from discontinued operations, net of taxes									0.0	0.0	(0.6)
Net income attributable to U.S. Concrete	$ 3.9	$ 13.0	$ 0.7	$ (2.7)	$ 2.0	$ 15.6	$ 16.3	$ (3.9)	$ 14.9	$ 30.0	$ 25.5
Denominator: (in shares)
Basic weighted average common shares outstanding (in shares)									16.4	16.5	15.9
Restricted stock and restricted stock units (in shares)									0.0	0.0	0.1
Warrants (in shares)									0.0	0.0	0.6
Denominator for diluted earnings per share (in shares)									16.4	16.5	16.6