SEGMENT REPORTING (Segment Financial Disclosure) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total revenues	[1]	$ 996,511	$ 854,474
Gross profit		191,675	159,334
Depreciation, Depletion, Accretion and Amortization (DDA&A)		89,181	81,439
Cash and cash equivalents and restricted cash		31,108	46,514	$ 44,404	$ 146,646
Total assets		10,296,852	9,453,211	$ 9,832,130
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	[1]	1,052,643	906,396
Total assets		10,132,398	9,265,699
Intersegment Sales [Member]
Segment Reporting Information [Line Items]
Total revenues	[1]	(56,132)	(51,922)
Aggregates [Member]
Segment Reporting Information [Line Items]
Total revenues	[1]	778,833	647,735
Aggregates [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	[1],[2]	834,965	699,657
Gross profit		185,716	148,221
Depreciation, Depletion, Accretion and Amortization (DDA&A)		72,521	65,953
Total assets	[3]	9,275,593	8,545,904
Aggregates [Member] | Intersegment Sales [Member]
Segment Reporting Information [Line Items]
Total revenues	[1]	(56,132)	(51,922)
Asphalt [Member]
Segment Reporting Information [Line Items]
Total revenues	[1]	132,090	103,835
Asphalt [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	[1],[4]	132,090	103,835
Gross profit		(3,272)	246
Depreciation, Depletion, Accretion and Amortization (DDA&A)		8,550	7,002
Total assets	[3]	564,103	447,961
Asphalt [Member] | Intersegment Sales [Member]
Segment Reporting Information [Line Items]
Total revenues	[1]	0	0
Concrete [Member]
Segment Reporting Information [Line Items]
Total revenues	[1]	83,637	100,962
Concrete [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	[1]	83,637	100,962
Gross profit		8,563	10,320
Depreciation, Depletion, Accretion and Amortization (DDA&A)		2,964	3,414
Total assets	[3]	288,797	267,678
Concrete [Member] | Intersegment Sales [Member]
Segment Reporting Information [Line Items]
Total revenues	[1]	0	0
Calcium [Member]
Segment Reporting Information [Line Items]
Total revenues	[1]	1,951	1,942
Calcium [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total revenues	[1]	1,951	1,942
Gross profit		668	547
Depreciation, Depletion, Accretion and Amortization (DDA&A)		60	69
Total assets	[3]	3,905	4,156
Calcium [Member] | Intersegment Sales [Member]
Segment Reporting Information [Line Items]
Total revenues	[1]	0	0
Other Segments [Member]
Segment Reporting Information [Line Items]
Depreciation, Depletion, Accretion and Amortization (DDA&A)		5,086	5,001
Corporate [Member]
Segment Reporting Information [Line Items]
Total assets		$ 133,346	$ 140,998

[1] The geographic markets are defined by states/countries as follows:East market - Arkansas, Delaware, Illinois, Kentucky, Maryland, North Carolina, Pennsylvania, Tennessee, Virginia, and Washington D.C.Gulf Coast market - Alabama, Florida, Georgia, Louisiana, Mexico, Mississippi, Oklahoma, South Carolina, Texas and the BahamasWest market - Arizona, California and New Mexico

[2] Includes product sales (crushed stone, sand and gravel, sand, and other aggregates), as well as freight & delivery costs that we pass along to our customers, and service revenues (see Note 4) related to aggregates.

[3] Certain temporarily idled assets are included within a segment's Identifiable Assets but the associated DDA&A is shown within Other in the DDA&A section above as the related DDA&A is excluded from segment gross profit.

[4] Includes product sales, as well as service revenues (see Note 4) from our asphalt construction paving business.