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ACQUISITIONS AND DIVESTITURES (Narrative) (Details)	3 Months Ended			12 Months Ended
ACQUISITIONS AND DIVESTITURES (Narrative) (Details)	Dec. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2016 USD ($) item property	Dec. 31, 2015 USD ($) property	Dec. 31, 2014 USD ($) item property shares
Significant Acquisitions and Disposals [Line Items]
Cash consideration				$ 32,537,000	$ 27,198,000	$ 284,237,000
Total consideration				33,287,000	47,198,000	331,836,000
Payable to seller				750,000
Exchanges of real property and businesses					20,000,000	2,414,000
Prepaid expenses	$ 31,726,000			31,726,000	34,284,000
Gain on sale of property, plant & equipment and businesses				15,431,000	9,927,000	244,222,000
Proceeds from sale of businesses, net of transaction costs				0	0	721,359,000
Proceeds From Sale Of Property Plant And Equipment				23,318,000	8,218,000	26,028,000
Amortizable intangible assets recognized						128,286,000
Goodwill of acquired businesses				0		13,303,000
Consideration transferred, common stock				0	0	$ 45,185,000
Common stock issued in connection with business acquisitions \| shares						715,004
Virginia Plant Relocation [Member]
Significant Acquisitions and Disposals [Line Items]
Gain on sale of property, plant & equipment and businesses	4,335,000
Proceeds From Sale Of Property Plant And Equipment	6,000,000
Acquisitions 2016 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized				$ 16,670,000
Acquisitions 2015 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized					$ 17,734,000
California [Member] \| California ready-mixed concrete operations [Member]
Significant Acquisitions and Disposals [Line Items]
Number of facilities divested \| property					12
Gain on sale of property, plant & equipment and businesses		$ 5,886,000
California And Virginia [Member]
Significant Acquisitions and Disposals [Line Items]
Gain on sale of property, plant & equipment and businesses	11,871,000
Proceeds From Sale Of Property Plant And Equipment	$ 19,185,000
Aggregates [Member] \| Tennessee [Member]
Significant Acquisitions and Disposals [Line Items]
Number of facilities acquired \| property					1
Gain on sale of property, plant & equipment and businesses			$ 5,790,000
Proceeds From Sale Of Property Plant And Equipment			5,820,000
Aggregates [Member] \| Arizona and New Mexico [Member]
Significant Acquisitions and Disposals [Line Items]
Number of facilities acquired \| property					3	5
Aggregates [Member] \| California [Member] \| Southern California Acquisition [Member]
Significant Acquisitions and Disposals [Line Items]
Number of facilities acquired \| property						1
Aggregates [Member] \| California [Member] \| San Francisco Bay Area Acquisition [Member]
Significant Acquisitions and Disposals [Line Items]
Number of facilities acquired \| property						4
Aggregates [Member] \| Delaware [Member]
Significant Acquisitions and Disposals [Line Items]
Number of facilities acquired \| property						2
Aggregates [Member] \| Texas [Member]
Significant Acquisitions and Disposals [Line Items]
Number of facilities acquired \| property				1
Aggregates [Member] \| Maryland [Member]
Significant Acquisitions and Disposals [Line Items]
Gain on sale of property, plant & equipment and businesses			168,000
Proceeds From Sale Of Property Plant And Equipment			10,727,000
Concrete [Member] \| Arizona and New Mexico [Member]
Significant Acquisitions and Disposals [Line Items]
Number of facilities acquired \| property					7
Asphalt Mix [Member] \| Arizona [Member]
Significant Acquisitions and Disposals [Line Items]
Number of facilities acquired \| property					13
Asphalt Mix [Member] \| California [Member]
Significant Acquisitions and Disposals [Line Items]
Number of facilities acquired \| property						2
Asphalt Mix [Member] \| New Mexico [Member]
Significant Acquisitions and Disposals [Line Items]
Number of facilities acquired \| property				1
Cement And Concrete [Member]
Significant Acquisitions and Disposals [Line Items]
Gain on sale of property, plant & equipment and businesses			227,910,000
Proceeds from sale of businesses, net of transaction costs			$ 721,359,000
Supply agreement period			20 years
Rail-connected aggregates operation [Member] \| Texas [Member]
Significant Acquisitions and Disposals [Line Items]
Number of facilities acquired \| item						1
Distribution yards [Member] \| Texas [Member]
Significant Acquisitions and Disposals [Line Items]
Number of distribution yard acquired \| property						2
Permitted aggregates quarry [Member] \| Alabama [Member]
Significant Acquisitions and Disposals [Line Items]
Number of facilities acquired \| item						1
Distribution Business Assets [Member] \| Georgia [Member]
Significant Acquisitions and Disposals [Line Items]
Number of facilities acquired \| item				1
Contractual Rights In Place [Member] \| Acquisitions 2016 [Member]
Significant Acquisitions and Disposals [Line Items]
Intangible assets amortization period, tax purposes				15 years
Contractual Rights In Place [Member] \| Acquisitions 2015 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized					$ 17,484,000
Intangible assets amortization period, tax purposes				15 years
Contractual Rights In Place [Member] \| Acquisitions 2014 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized						$ 36,921,000
Estimated weighted-average amortization period of intangible assets				40 years
Intangible assets amortization period, tax purposes				15 years
Contractual Rights In Place - Straight-Line Method [Member] \| Acquisitions 2016 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized				$ 6,798,000
Estimated weighted-average amortization period of intangible assets				20 years
Contractual Rights In Place - Straight-Line Method [Member] \| Acquisitions 2015 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized					7,168,000
Estimated weighted-average amortization period of intangible assets				20 years
Contractual Rights In Place - Units Of Production [Member] \| Acquisitions 2016 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized				$ 8,415,000
Estimated weighted-average amortization period of intangible assets				20 years
Contractual Rights In Place - Units Of Production [Member] \| Acquisitions 2015 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized					10,317,000
Estimated weighted-average amortization period of intangible assets				34 years
Noncompetition Agreements [Member] \| Acquisitions 2015 [Member]
Significant Acquisitions and Disposals [Line Items]
Amortizable intangible assets recognized					$ 250,000