Changes in Goodwill (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2016 USD ($)
Goodwill [Line Items]
Balance at beginning of period	$ 2,068,235
Acquisitions	92,442
Disposal	(72)
Balance at end of period	2,160,605
Mid-America Group
Goodwill [Line Items]
Balance at beginning of period	281,403
Balance at end of period	281,403
Southeast Group
Goodwill [Line Items]
Balance at beginning of period	50,346
Balance at end of period	50,346
West Group
Goodwill [Line Items]
Balance at beginning of period	871,220
Acquisitions	92,442
Disposal	(72)
Balance at end of period	963,590
Cement
Goodwill [Line Items]
Balance at beginning of period	865,266
Balance at end of period	$ 865,266