ACQUISITIONS AND DIVESTITURES (Narrative) (Details) - USD ($)	3 Months Ended				6 Months Ended			12 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2017	Jun. 30, 2018		Jun. 30, 2017	Dec. 31, 2017
Significant Acquisitions and Disposals [Line Items]
Consideration transferred, net of assets divested								$ 842,013,000
Total consideration					$ 217,440,000			1,080,815,000
Cash consideration					218,996,000		$ 210,562,000	822,432,000
Consideration payable amount								9,681,000
Assets acquired			$ 9,900,000					9,900,000
Goodwill					41,633,000	[1]		27,497,000
Deferred income taxes, net	$ 36,172,000				36,172,000
Proceeds from sale of property, plant & equipment					8,523,000		8,530,000
Gain on sale of property, plant & equipment and businesses	2,106,000			$ 2,773,000	6,270,000		3,142,000
Assets held for sale	0		0	$ 0	0		$ 0	0
Aggregates USA [Member]
Significant Acquisitions and Disposals [Line Items]
Amount of assets divested			287,292,000					287,292,000
Gain on sale of property, plant & equipment and businesses			0
Acquisitions 2018 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized					$ 90,803,000
Intangible assets amortization period, tax purposes					15 years
Goodwill					$ 40,641,000
Intangible assets, deductible for income tax purposes	4,720,000				4,720,000
Goodwill, deductible for income tax purposes	$ 0				$ 0
Acquisitions 2017 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized								309,112,000
Intangible assets amortization period, tax purposes					15 years
Goodwill					$ 992,000
Arizona [Member]
Significant Acquisitions and Disposals [Line Items]
Gain on sale of property, plant & equipment and businesses			8,021,000
Assets divested, fair value			9,900,000					9,900,000
Assets held for sale			$ 1,879,000					1,879,000
Georgia [Member]
Significant Acquisitions and Disposals [Line Items]
Gain on sale of property, plant & equipment and businesses		$ 2,929,000
Contractual Rights In Place [Member] | Acquisitions 2017 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized								309,012,000
Contractual Rights In Place - Straight-Line Method [Member] | Acquisitions 2018 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized					$ 89,723,000
Estimated weighted-average amortization period of intangible assets					20 years
Contractual Rights In Place - Straight-Line Method [Member] | Acquisitions 2017 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized								73,879,000
Estimated weighted-average amortization period of intangible assets					19 years 3 months 18 days
Contractual Rights In Place - Units Of Sales [Member] | Acquisitions 2018 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized					$ 1,080,000
Estimated weighted-average amortization period of intangible assets					20 years
Contractual Rights In Place - Units Of Sales [Member] | Acquisitions 2017 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized								235,133,000
Estimated weighted-average amortization period of intangible assets					54 years 8 months 12 days
Other Intangibles [Member] | Acquisitions 2017 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized								$ 100,000

[1] See Note 16 for a summary of acquisitions.