SEGMENT INFORMATION - Schedule of Certain Financial Information Relating to Continuing Operations by Reportable Segment (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) reporting_segment	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | reporting_segment									2
Revenue	$ 369.2	$ 408.9	$ 367.5	$ 333.1	$ 370.1	$ 404.3	$ 404.2	$ 327.8	$ 1,478.7	$ 1,506.4	$ 1,336.0
Total reportable segment Adjusted EBITDA									211.5	220.8	213.0
Other products and eliminations income from operations	$ 18.0	$ 33.3	$ 6.0	$ 7.9	$ 16.7	$ 35.0	$ 30.6	$ 7.6	65.2	89.9	79.0
Depreciation, depletion and amortization for reportable segments									(93.2)	(91.8)	(67.8)
Interest expense, net									(46.1)	(46.4)	(42.1)
Eminent domain matter									5.3	(0.7)	0.0
Change in value of contingent consideration for reportable segments									(2.8)	0.0	(7.9)
Litigation settlement costs									(0.3)	(2.1)	0.0
Acquisition-related costs, net									1.0	(1.4)	0.0
Impairment of goodwill and other assets									0.0	(1.3)	(6.2)
Quarry dredge costs for specific event for reportable segments									0.0	(1.1)	(3.4)
Corporate derivative loss									0.0	0.0	(0.8)
Corporate, other products and eliminations other loss (income), net									9.5	4.6	2.5
Income from continuing operations before income taxes									28.6	48.1	38.6
Income tax expense									12.3	16.8	12.4
Income from continuing operations									16.3	31.3	26.2
Ready-mixed concrete
Segment Reporting Information [Line Items]
Total reportable segment Adjusted EBITDA									157.7	179.2	185.8
Aggregate products
Segment Reporting Information [Line Items]
Revenue									141.7	136.5	49.8
Total reportable segment Adjusted EBITDA									53.8	41.6	27.2
Operating Segments
Segment Reporting Information [Line Items]
Revenue									1,473.8	1,489.1	1,303.7
Depreciation, depletion and amortization for reportable segments									(86.1)	(85.8)	(63.1)
Impairment of goodwill and other assets									0.0	(1.3)	(6.2)
Purchase accounting adjustments for inventory									0.0	(0.8)	(1.3)
Operating Segments | Ready-mixed concrete
Segment Reporting Information [Line Items]
Revenue									1,278.6	1,306.5	1,213.0
Operating Segments | Aggregate products
Segment Reporting Information [Line Items]
Revenue									195.2	182.6	90.7
Intersegment sales | Aggregate products
Segment Reporting Information [Line Items]
Revenue									53.5	46.1	40.9
Other products and eliminations
Segment Reporting Information [Line Items]
Revenue									4.9	17.3	32.3
Other products and eliminations income from operations									3.3	21.7	10.8
Corporate, other products and eliminations other loss (income), net									0.9	(0.7)	(1.1)
Corporate overhead
Segment Reporting Information [Line Items]
Corporate overhead									(59.5)	(54.9)	(56.3)
Hurricane-Related Losses
Segment Reporting Information [Line Items]
Gain (loss) from unusual or infrequent item									2.1	0.8	(3.0)
Fire
Segment Reporting Information [Line Items]
Gain (loss) from unusual or infrequent item									$ (0.7)	$ 0.0	$ 0.0