LEASES (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating Leased Assets [Line Items]
Cash paid for operating leases	$ 13,333,000
Finance leases	0
Nonmineral operating lease expense	$ 25,285,000	$ 24,352,000
Minimum [Member] | Buildings [Member]
Operating Leased Assets [Line Items]
Noncancellable lease period	1 year
Term of contract	1 year
Minimum [Member] | Aggregate Sales Yard [Member]
Operating Leased Assets [Line Items]
Noncancellable lease period	0 years
Term of contract	2 years
Minimum [Member] | Concrete And Asphalt Site [Member]
Operating Leased Assets [Line Items]
Noncancellable lease period	0 years
Term of contract	1 year
Minimum [Member] | Rail [Member]
Operating Leased Assets [Line Items]
Noncancellable lease period	0 years
Term of contract	2 years
Minimum [Member] | Barge [Member]
Operating Leased Assets [Line Items]
Noncancellable lease period	2 years
Term of contract	10 years
Minimum [Member] | Office And Plant Equipment [Member]
Operating Leased Assets [Line Items]
Noncancellable lease period	0 years
Term of contract	0 years
Maximum [Member] | Buildings [Member]
Operating Leased Assets [Line Items]
Noncancellable lease period	30 years
Term of contract	30 years
Maximum [Member] | Aggregate Sales Yard [Member]
Operating Leased Assets [Line Items]
Noncancellable lease period	13 years
Term of contract	80 years
Maximum [Member] | Concrete And Asphalt Site [Member]
Operating Leased Assets [Line Items]
Noncancellable lease period	97 years
Term of contract	97 years
Maximum [Member] | Rail [Member]
Operating Leased Assets [Line Items]
Noncancellable lease period	7 years
Term of contract	76 years
Maximum [Member] | Barge [Member]
Operating Leased Assets [Line Items]
Noncancellable lease period	3 years
Term of contract	16 years
Maximum [Member] | Office And Plant Equipment [Member]
Operating Leased Assets [Line Items]
Noncancellable lease period	4 years
Term of contract	4 years