ACQUISITIONS AND DIVESTITURES (Narrative) (Details) - USD ($) $ in Thousands		3 Months Ended			12 Months Ended
		Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Significant Acquisitions and Disposals [Line Items]
Consideration transferred, net of assets divested						$ 793,523
Total consideration					$ 219,863	1,080,815	$ 33,287
Cash consideration					221,419	1,109,725	32,537
Cash					215,363	1,072,978
Consideration payable amount					4,500		750
Goodwill	[1]				43,075	27,497
Deferred income taxes, net					32,871
Gain on sale of property, plant & equipment and businesses					14,944	17,827	15,431
Proceeds from sale of property, plant & equipment					22,210	15,756	23,318
Assets divested, Book Value			$ 0	$ 0	0	0	0
Aggregates USA [Member]
Significant Acquisitions and Disposals [Line Items]
Amount of assets divested			287,292			287,292
Gain on sale of property, plant & equipment and businesses			0
Virginia Plant Relocation [Member]
Significant Acquisitions and Disposals [Line Items]
Gain on sale of property, plant & equipment and businesses				4,335
Proceeds from sale of property, plant & equipment				6,000
Acquisitions 2018 [Member]
Significant Acquisitions and Disposals [Line Items]
Cash consideration					215,363
Amortizable intangible assets recognized					$ 44,163
Intangible assets amortization period, tax purposes					15 years
Goodwill					$ 42,325
Intangible assets, deductible for income tax purposes					7,385
Goodwill, deductible for income tax purposes					4,468
Deferred income taxes, net					$ 32,871
Acquisitions 2017 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized						309,112
Intangible assets amortization period, tax purposes					15 years
Goodwill					$ 28,247	28,247
Goodwill, deductible for income tax purposes					28,247
Goodwill increase					$ 750
Acquisitions 2016 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized							16,670
Immaterial Business Acquisitions [Member]
Significant Acquisitions and Disposals [Line Items]
Total consideration						48,490
Cash consideration						36,746
Consideration payable amount						1,844
Assets acquired			9,900			9,900
Arizona [Member]
Significant Acquisitions and Disposals [Line Items]
Gain on sale of property, plant & equipment and businesses			8,021
Assets divested, fair value			9,900			9,900
Assets divested, Book Value			$ 1,879			1,879
California And Virginia [Member]
Significant Acquisitions and Disposals [Line Items]
Gain on sale of property, plant & equipment and businesses				11,871
Proceeds from sale of property, plant & equipment				$ 19,185
Georgia [Member]
Significant Acquisitions and Disposals [Line Items]
Gain on sale of property, plant & equipment and businesses		$ 2,929
Contractual Rights In Place [Member] | Acquisitions 2017 [Member]
Significant Acquisitions and Disposals [Line Items]
Intangible assets amortization period, tax purposes					15 years
Contractual Rights In Place [Member] | Acquisitions 2016 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized							15,213
Intangible assets amortization period, tax purposes					15 years
Contractual Rights In Place - Straight-Line Method [Member] | Acquisitions 2018 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized					$ 43,072
Estimated weighted-average amortization period of intangible assets					19 years 10 months 24 days
Contractual Rights In Place - Straight-Line Method [Member] | Acquisitions 2017 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized						73,879
Estimated weighted-average amortization period of intangible assets					19 years 3 months 18 days
Contractual Rights In Place - Straight-Line Method [Member] | Acquisitions 2016 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized							6,798
Estimated weighted-average amortization period of intangible assets					20 years
Contractual Rights In Place - Units Of Sales [Member] | Acquisitions 2018 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized					$ 1,080
Estimated weighted-average amortization period of intangible assets					30 years
Contractual Rights In Place - Units Of Sales [Member] | Acquisitions 2017 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized						$ 235,133
Estimated weighted-average amortization period of intangible assets					54 years 8 months 12 days
Contractual Rights In Place - Units Of Sales [Member] | Acquisitions 2016 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized							8,415
Estimated weighted-average amortization period of intangible assets					20 years
Noncompetition Agreements [Member] | Acquisitions 2016 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized							$ 1,457

[1] See Note 19 for a summary of acquisitions