SEGMENT INFORMATION - Reconciliation of Total Reportable Segment Adjusted EBITDA to Income (Loss) From Continuing Operations (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($) reporting_segment	Mar. 31, 2019 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | reporting_segment	2
Revenue by Segment:
Revenue	$ 334.4	$ 333.1
Reconciliation of Total Reportable Segment Adjusted EBITDA to Net Income:
Total reportable segment Adjusted EBITDA	43.0	44.9
Operating income	3.1	7.9
Depreciation, depletion and amortization for reportable segments	(23.4)	(22.8)
Interest expense, net	(11.4)	(11.6)
Change in value of contingent consideration for reportable segments	(0.3)	(1.0)
Corporate, other products and eliminations other income (loss), net	0.6	0.4
Income (loss) before income taxes, equity in earnings of subsidiaries and non-controlling interest	(7.7)	(3.3)
Income tax benefit (expense)	4.9	0.7
Net income (loss)	(2.8)	(2.6)
Capital Expenditures:
Total capital expenditures	7.3	7.2
Ready-mixed concrete
Reconciliation of Total Reportable Segment Adjusted EBITDA to Net Income:
Total reportable segment Adjusted EBITDA	31.7	34.5
Aggregate products
Revenue by Segment:
Revenue	31.1	31.8
Reconciliation of Total Reportable Segment Adjusted EBITDA to Net Income:
Total reportable segment Adjusted EBITDA	11.3	10.4
Reportable segment
Revenue by Segment:
Revenue	335.8	333.3
Reconciliation of Total Reportable Segment Adjusted EBITDA to Net Income:
Depreciation, depletion and amortization for reportable segments	(21.8)	(20.8)
Purchase accounting adjustments for inventory	(1.6)	0.0
Capital Expenditures:
Total capital expenditures	7.3	7.2
Reportable segment | Ready-mixed concrete
Revenue by Segment:
Revenue	292.2	290.4
Capital Expenditures:
Total capital expenditures	4.4	5.8
Reportable segment | Aggregate products
Revenue by Segment:
Revenue	43.6	42.9
Capital Expenditures:
Total capital expenditures	2.8	1.2
Intersegment sales | Aggregate products
Revenue by Segment:
Revenue	12.5	11.1
Other products and eliminations
Revenue by Segment:
Revenue	(1.4)	(0.2)
Reconciliation of Total Reportable Segment Adjusted EBITDA to Net Income:
Operating income	0.1	(0.1)
Corporate, other products and eliminations other income (loss), net	(0.1)	0.4
Capital Expenditures:
Total capital expenditures	0.1	0.2
Corporate overhead
Reconciliation of Total Reportable Segment Adjusted EBITDA to Net Income:
Corporate overhead	(15.6)	(14.5)
Mixer truck fire
Reconciliation of Total Reportable Segment Adjusted EBITDA to Net Income:
Unusual or Infrequent Item, or Both, Net (Gain) Loss	$ 0.0	$ 0.6