BUSINESS COMBINATION - Additional Information (Narrative) (Details) T in Millions, $ in Millions		3 Months Ended
	Feb. 24, 2020 USD ($) a T	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)
Business Acquisition [Line Items]
Acquisitions funded by deferred consideration		$ 1.7	$ 0.0
Coram Material Corp.
Business Acquisition [Line Items]
Total consideration (fair value)	$ 142.9
Consideration satisfied in cash	140.2
Acquisitions funded by deferred consideration	1.7
Working capital payable	$ 1.6
Area of land (acres) | a	330
Area of land, mining acres (acres) | a	180
Proven aggregate reserves (tons) | T	41.9
Proven but unpermitted aggregate reserves (tons) | T	7.5
Transaction costs		$ 0.5